Turbine Maintenance Book

印尼中爪哇 2×300MW 工程

湖北华电青山热电有限公司 2005 年

目录 CHAPTER 1 SECTION 1 SECTION 2 SECTION3

MAINTENANCE DURING THE OPERATION OF TURBINE ...................................- 3 ROUTINE MAINTENANCE DURING OPERATION ........................................................................ - 3 SUPERVISION AND REGULATION OF THE SAFETY AND ECONOMY DURING OPERATION ........... - 6 INSPECTION PROJECTS FOR THE OVERHAUL AND MINI-OVERHAUL OF UNITS ........................... - 9 -

CHAPTER 2 汽轮机自控维护 ......................................................................................................................- 12 SECTION1 SECTION2 SECTION3 SECTION4

INSTRUCTION ON ELECTRIC MONITORING SYSTEM OF STEAM TURBINE ............................... - 12 MANUAL OF EMERGENCY TRIPPING DEVICE OF STEAM TURBINE ............................................ - 33 INSTRUCTION ON AUTOMATIC OPERATION DEVICE FOR TURNING GEAR .................................. - 42 DIGITAL ELECTRO-HYRAULIC (DEH) CONTROL SYSTEM SPECIFICATIONS .......................... - 53 -

CHAPTER 3 辅机维护 ................................................................................................................................ - 110 SECTION1 SPECIFICATION FOR MAIN BODY OF STEAM TURBINE AND LINE DRAINAGE SYSTEM(N300-16.7/537/537-8) .................................................................................................................. - 110 SECTION2 N-17750 CONDENSER SPECIFICATIONS ................................................................................ - 117 SECTOION3 SPECIFICATION FOR PNEUMATIC CONTROL SYSTEM OF STEAM EXTRACTION CHECK VALVE OF

STEAM TURBINE（N300-16.7/537/537-8） ............................................................................................... - 130 SECTION4 SELF-SEALING TURBINE STEAM SEAL SYSTEM SPECIFICATIONS ......................................... - 134 SECTION5 MAINTENANCE OF CONDENSATE PUMP ................................................................................. - 148 SECTION6 FEEDWATER PUMP................................................................................................................ - 151 SECTION7 LP HEATER SYSTEM SPECIFICATIONS .................................................................................. - 160 CHAPTER4 汽轮机油系统维护 .................................................................................................................- 166 SECTION1 SPECIFICATION FOR LUBRICATING SYSTEM .......................................................................... - 166 SECTION2 DESCRIPTION OF INTEGRATED OIL TANK ............................................................................... - 174 SECTION3 MANUAL OF SHAFT-JACKING DEVICE .................................................................................... - 180 SECTION4 MANUAL OF OIL INJECTOR .................................................................................................... - 185 SECTION5 MAIN OIL PUMP DESCRIPTION................................................................................................... - 188 SECTION6 INSTRUCTION FOR SPILL VALVE ............................................................................................ - 190 SECTION7 INSTRUCTION FOR TWIN-TONGUE CHECK VALVE................................................................. - 194 SECTION8 OPERATING INSTRUCTION FOR OIL SMOKE SEPARATOR ....................................................... - 197 -

CHAPTER5 INSTRUCTION OF HYDROGEN、SEAL OIL、STATOR COOLING WATER SYSTEM FOR 300MW GENERATOR .......................................................................................................................- 199 SECTION1 GENERAL ........................................................................................................................... - 199 SECTION2 HYDROGEN CONTROL SYSTEM(SEE HYDROGEN CONTROL SYSTEM DIAGRAM)....................... - 199 SECTION3 SEAL OIL CONTROL SYSTEM(SEE THE SEAL OIL CONTROL SYSTEM DIAGRAM) ...................... - 204 SECTION4 STATOR WINDING COOLING WATER SYSTEM(SEE STATOR WINDING COOLING WATER CONTROL SYSTEM DIAGRAM)....................................................................................................................................... - 208 -

CHAPTER6

DESCRIPTION OF CIRCULATING WATER SYSTEM.............................................- 212 -

SECTION1 SECTION2 SECTION3 SECTION4

GENERAL SITUATION ............................................................................................................ - 212 DESIGN DESCRIPTION OF CIRCULATING WATER SYSTEM ....................................................... - 213 THE CONSTRUCTION AND INSTALLATION DESCRIPTION OF THE CIRCULATING WATER SYSTEM - 217 OPERATING MANAGEMENT DESCRIPTION OF CIRCULATING WATER SYSTEM .......................... - 218 -

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Chapter 1

Maintenance during the Operation of Turbine

Section 1

Routine Maintenance during Operation

Operation of turbine with load is one of important section during the production of electric power. It is the duty of operation persons of turbine to perform correctly rules and to operate, check, supervise and regulate strictly during operation, and the precondition to ensure the safe and economic operation of turbine devices. Working contents of the routine maintenance during the operation of turbine are: (1) To supervise the related devices and meters via supervising panel, transcribing readings periodically, inspecting circularly, measuring vibration periodically, to do the meter analysis, and to check the safe and economic condition of operation. (2) To regulate the related operating parameters and patterns, to go through the economic distribution principle of load, to enable the devices to operate under the best condition, to reduce the ratio of heat consumption and auxiliary power, and to increase the economic efficiency of operation. (3) To enhance the supervision of failed devices, fault systems and devices under a special operation pattern, to prevent the trouble occurrences and enlargement, to increase the utilization factor and to ensure the safe operation of devices. (4) To do various protective tests periodically and the normal tests and shift operation of auxiliaries. In short, the main roles of operation of power plants are: to supply the needed electric energy to users or power network continuously & safely & economically. I. The shift persons should do the following while the turbine normally operating: (1) To supervise & operate & regulate strictly, notice at any time the variation of indication of each meter and adopt the corresponding maintenance measures, and to fill in the operation logs. (2) To read meters every one hour and analyze the data. if the reading is different from the normal value, the cause should be found out immediately and the necessary measures should be taken. (3) To inspect the unit periodically, especially notice the temperatures of babbit of each trust bearing pad and each bearing, the oil return temperature, oil flow and vibration, operation and tightness conditions of the cooling system of generator and prevention of oil leakage and fire catching. (4) To do the listening inspection for each part of turbine, especially while the operating condition changes greatly. (5) To inspect periodically or contact with maintenance persons to clean the screens installed in the steam or water or oil system in terms of the exact condition during operation. (6) To regulate in time the steam pressure of shaft sealing, to prevent leaking steam caused by too high pressure from entering the bearing box, resulting in the deterioration of oil quality; and simultaneously prevent air leakage of low-pressure casing gland caused by too low pressure resulting in the drop of the condenser vacuum. (7) To keep the turbine operate under the economic condition, and the following conditions should be met: a) To retain the main steam temperature at the rating, steam pressure conform to the prescribed value of variable pressure operation curve of the unit, and the variation does not exceed the permissible range. b) The regenerative system should run normally, the outlet water temperature of heater should confirm to the designed value or in the range prescribed by the rules.

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c) To keep the condenser operating under the best condition, check the steam extraction temperature of turbine periodically and regulate it in time if necessary. d) The degree of supercooling of the condensate should not exceed the prescribed value. (8) To do the various periodic shifts and tests. (9) To clean the devices of turbine generator periodically II. Control parameters during the normal operation In order to ensure the safe and economic operation of turbine devices, operation persons should supervise and analyze the operating condition of devices via various meters and regulate if necessary except for a visual method, to retain the various value in the permissive range. The values which should often be supervised are: the load of turbine, temperature and pressure of the main steam, vacuum of the condenser, rotary speed of turbine (frequency) and running condition of rotary devices. The parameters which should often be inspected are: steam pressure of regulating chamber, steam pressure and temperature of each extraction port, main steam flow, water temperature and level of inlet and outlet of each heater, oil level of oil tank, anti-fire oil pressure, pressure and temperature of lubrication, vibration of each bearing, thermal expansion and its difference of the unit, axial displacement of rotor, metal temperature of trust bearing and main bearing, opening of steam regulating valve and wind temperature of outlet of generator and so on. Under the normal condition, the above parameters have a certain inherent connection, such as: while the load of generator is increased, the steam flow into the turbine will increase owing to the invariable main steam parameters, the opening of regulating valve is also increased correspondingly, the steam pressure of regulating chamber and steam extraction pressure of each section is increased proportionally (for the condensate unit), the steam temperature before each section is also increased, and the thermal expansion of the unit is increased; if the relationship between these parameters is out of rear during operation, there is something wrong with the unit. if the steam pressure of regulating chamber and each extraction port is higher than the pressure corresponding to the normal condition with this power, the scaling or block exist in the flowing part. Because the unit type is different, the value prescribed by operation rules of each unit have to be carried out, these parameters can be kept in the permissive changing range via check, analysis, regulation and maintenance, to ensure the safe and economic operation of the unit. III. Inspection during operation Inspection is one of the important measures to understand devices, grasp the operation condition, find the hidden trouble and ensure the safe operation of devices. Hence, the following matters should be done carefully and strictly: 1. Inspection of the turbine proper (1) The total expansion indication of turbine, oil return temperature and quantity, vibration, servomotor travel and action of regulating valve and so on. (2) Bearing: oil return temperatures of all the bearing pads, oil quantity, vibration, the leakage of oil baffle. (3) Cylinder: shaft sealing admission, running sound of the unit, relative expansion, vibration of exhaust casing and exhaust temperature. (4) Generator and exciter: wind temperature of outlet and inlet, cooling water pressure and temperature of each cooler etc.

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(5) The devices of turning gear: the handle should be arranged at the OFF position, and the operating power source should be right. (6) The main automatic stop valve: the indication of position of the main stop valve, smooth flowing of cooling water (7) The main meter panel: the indication of pressure and vacuum of steam, water and oil systems, relative expansion difference and indication of axial displacement. 2. Inspection of the pumps (1) Motor: current, interlock "on" position, wind temperature of outlet, temperature and vibration of bearing, running sound, good grounding wiring and firm foundational bolts. (2) Pump: the outlet pressure should be right, gland packing should be of no heating or watering, the running sound should be right, the cooling water of bearing pad should be smooth, the water discharge hopper has no block, the oil level of bearing is normal and quality of oil is good, the oil ring can carry oil normally and has no leakage, coupler hood is fixed well. (3) The insulation of tubes connecting with pump should be all right, its support rack is fast and has no leakage, and opening of valve should be normal. (4) The relative meters should be complete and perfect, and its indication should be correct. 3. Inspection of feed water pump Except for the above items, the following items should be inspected because the feed water pump has its own lubrication system: (1) Indication of the pressure of balance disk should be normal.

(2) Position of the water inlet and outlet valve of cooling wind chamber of motor of motor-driven feed water pump and the condition of wind temperature. (3) Oil and water temperature condition and oil pressure of outlet and inlet of oil cooler should be normal. (4) The operating condition of hydraulic coupler. 4. Inspection of other auxiliaries (1) The level of lubrication tank, anti-fire oil tank and auxiliary oil tank should be normal, the operation of flue gas exhauster. (2) Oil cooler: the temperature of outlet and inlet should be normal; waterside has no accumulated gas or leakage of oil and water. The oil pressure should be more than the water pressure. (3) Each oil pump, oil filter and low-level oil tank, the oil level should be normal. (4) The main air ejector and shaft seal air ejector: the pressure of working steam or water, vacuum, water seal of vacuum break valve should be normal, the rotary devices using vacuum pumps should have abnormality and each component should have no overheat. (5) Condenser: the water level of condenser, the pressure and temperature of the condensate outlet and inlet, the temperature of condensate and the position of switch of each valve. (6) HP and LP heaters: the water level, the pressure of extraction steam, the position of the switch of valve, the protective water source of hydraulic check valve should be put into operation, the working condition of water level regulation, the piping and flanges should have no leakage of water and steam. (7) Shaft seal cooler: water level, the condition of siphon well, the position of watering valve, the condition of steam extraction of exhaust outlet, the sufficient water flowing quantity. (8) Drain expander: the switch of valves should be right and have no leakage of steam. (9) Deaerator: the pressure, temperature and water level should be normal, the condition of steam extraction, and the position of switch of each valve, the working condition of water level regulator. Also, the flange of tube should have no leakage of water and steam

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and the safety valve should work normally. The abnormal condition should be analyzed carefully and its causes should be found out and eliminated if it is found during inspection. The measures should be taken if the abnormity cannot be eliminated immediately, to prevent the enlargement of the trouble, and the trouble should be recorded and reported. IV.

Test during the normal operation and shifting of auxiliaries In order to ensure the safety of the main devices, their protections and auxiliaries should be safe and reliable, to avoid the damage to the main devices or shutdown caused by the fault of protections or auxiliaries, so the following should be done: (1) To operate the main stop valve periodically. The load should be changed in a large range periodically for the turbine carrying a stationary load, to prevent the lever of regulating valve from logging.

(2) Water (steam) pressure check valve on each regenerative extraction pipe, check valve and safety valve on the regulating extraction pipe should be tested and verified periodically according to the rules. If a fault occurs to one check valve or safety valve, it should be eliminated immediately or the corresponding measures should be taken. (3) The reserve emergency oil pump and its self-starting installation should be tested periodically. In addition, this test should be done while the turbine starts or before the turbine is shut down. (4) The oil level should be done the movement test every day, and the accumulating water at the bottom of oil tank should be discharged periodically. (5) Various automatic protections, including annunciator and lighting signal, should be tested periodically during operation if possible. (6) The protection of HP heater should be tested periodically. If HP heater has no high-level protection or the protection is abnormal, it is forbidden to put into operation. (7) The sealing test should be done for the vacuum system periodically, in general, once every month. (8) The shifting test should be done for the auxiliaries periodically every day including the main air ejector, vacuum pump, condensate pump, boosting pump, drain pump, service water pump etc. The insulation condition of motor of the reserve pump (devices) should be supervised to prevent damage to the motor from fault enlarging as emergency start. In conclusion, the daily work is very complex during normal operation, so the operators should be with responsibility that the quality of the bank can be kept and the network can get the safe and economic supply.

Section 2

Supervision and Regulation of the Safety and Economy during Operation

Some important parameters during normal operation of turbine, such as the main steam parameters, vacuum of the condenser, axial displacement, expansion difference and the pressure of supervised section and so on, act as the crucial function to the safe and economic operation of turbine. Hence, these parameters should be supervised carefully during operation and regulated in time to retain in a prescribed range. I. The main steam parameters During the normal operation of turbine, the steam parameters may be deflected from the rating inevitably and temporarily. If the deflection is not more than the permissive range, it cannot damage the strength of the components of turbine, otherwise, it will result in troubles of reliability and safety of operation. While the initial and steam extraction pressure is

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invariable, the change of temperature of the main steam will result in the change of temperature of the whole thermal cycling source and the change of thermal efficiency of the circulation. If the temperature of the main steam rises, the ideal enthalpy drop in the turbine increases and the ability of doing work enhances. Oppositely, while the temperature of the main steam drops, the ability of doing working decreases and so the efficiency drops. Under the condition of complete opening of regulating valve, the seam flow through the turbine decreases along with the rise of initial temperature, and regulating blades may overload. The strength of metal will rapidly drop along with the rise of temperature. In addition, the creepage may occur to the metal with high temperature. So rapid overload and super temperature are dangerous, at present the manufacturer prescribes the upper limit of temperature, in general not more 5～8℃ than the rating. While the opening of regulating valve is given, the initial temperature drops and results in the increase of flow quantity; the enthalpy drop of regulating stage decrease, the enthalpy drop of the final stage increases, and the final stage is easy to overload; also, the initial temperature drops resulting in the humidity of extraction steam increases, the impulsion damage to the final stage blades increases; and the initial temperature drop will increase the axial thrust. So the initial temperature drop not only affects the economic efficiency of the unit operation but also threaten the safety operation of the unit. In order to ensure the safety, the load should be reduced while the initial temperature is less 15～20℃ than the rating. While the opening of regulating valve is invariable, initial temperature and backpressure are invariable and the initial pressure increases, all the stages of turbine will overload, thereinto, the final stage is most serious. Simultaneously, the rise of initial pressure will threaten the piping of turbine and other bearing components. The initial pressure drop does not affect the safety of the unit, but the output of the unit will drop. Hence, the main steam pressure is required to operate under the prescribed pressure; especially the unit operation should be retained according to the variable-pressure operating curve for the sliding-pressure operation unit. II. Vacuum of condenser Vacuum of condenser is namely the pressure of steam extraction of turbine, owing to the variation of steam load, the copper pipe is scaled, the tightness of vacuum system is deteriorated and the cooling water temperature changes, their values can be changed in a large range, directly affecting the safe and economic operation of the unit. While the vacuum drops, the total enthalpy drop of turbine will decrease, and the decrease mainly happens to the final stages. At this time, the stress of these stages will decrease and the reaction degree will increase. While the vacuum drops rapidly, the variation of reaction degree will cause the variation of axial thrust and the thrust bearing may have danger. In addition, if the vacuum is deteriorated severely, the temperature of extraction steam will rise, resulting in the variation of center of the unit, accordingly resulting in the nonpermissive vibration. So the vacuum of the unit is permitted to drop in a certain range during operation, or the load must be reduced, even the emergency shutdown should be done. While the vacuum increase, the enthalpy drop of the final stage of turbine increases, and the final stage may overload. Especially while the final stage reaches the critical flow condition, the further increase of enthalpy drop will be borne only by the final stage. The variation of condenser vacuum can greatly affect the economic efficiency of operation of the turbine. it mainly shows that the variation of vacuum will cause that of ability of doing work. So, the copper pipe should be kept clean during the practical operation, and the tightness of vacuum system should be kept qualified, to improve the economic efficiency of the unit operation.

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III. Monitoring of the pressure of supervised section In the condensing turbine, the pressure of steam chamber of the regulating stage and the pressure of extraction steam of each stage is directly proportional to the flow of the main steam. According to this theory, the operation of convection part can be supervised via the supervision of the pressure of steam chamber of the regulating stage and the pressure of extraction steam during operation. Hence, this pressure is called that of supervised pressure. In a common condition, the manufacturer gives the steam flow and pressure value of and each supervised section under the rating load of each turbine and the permissive maximum steam flow and the pressure value according to the calculating result of thermal and strength. The pressure of each supervised section is not identical under the same load even the same type of turbine because each unit has its own property. Hence, each unit should be measured according to the given data by manufacturer after installation or overhauling while the convection part is under the normal condition, to acquire the relationship among the load, main steam flow and pressure of supervised section, which acts as criteria for regular operation supervision. If the pressure of supervised section rises under the same load (flow), it shows that the convection area of the convection section decreases mostly because of the scaling, sometimes because some metal components are cataclastic or mechanical foreign matter is blocked in the convection part or the blade is damaged and deformed. So while a heater is out of service, the pressure of corresponding extraction steam section will rise if admission quantity of turbine is unchanged. Not only the pressure up of supervised section but also the pressure difference between each supervised section is noticed whether to exceed the prescribed value. If the pressure difference of a section exceeds the prescribed value, the working stress of this section of diaphragm and movable blade will increase, resulting in the damage to the devices. The severe scaling should be eliminated (in general, the pressure of supervised section of intermediate-pressure and LP unit raises relatively 15%, that of HP or above unit 10%); the following four kinds of methods are commonly used: (1) The turbine is shut down and the casing is opened, with a mechanical method. (2) To rinse with heated water under the slowly turning condition. (3) To rinse with wet heated steam under a low rotary speed. (4) To rinse with wet steam with load. IV. Supervision of axial displacement and the temperature of bearing pad 1. Axial displacement The index of the axial displacement of turbine rotor is used to supervise the working condition of the thrust bearing; the axial thrust functioning on the rotor is borne by the thrust bearing, to ensure the reliable axial clearance between movable and stationary parts. Too much axial thrust or abnormality of operation of bearing will result in the burning and damage to the thrust pad, to produce the damage to devices caused by the wear of movable and stationary part. Various turbines are equipped with axial displacement indicator, which is used to supervise the working condition of the thrust pad; the turbine should be forced to shutdown immediately if the displacement exceeds the permissive limit value, to prevent the convection part from damage. Different types of units have different ZERO positions of indicators. The number of positive value indicated by the axial displacement shows the axial displacement quantity at the thrust disk during operation of turbine. So, the indicators are arranged near the thrust pad. In general, the thrust clearance of an integrated thrust pad is in a range of 0.4 to 0.6mm or so.

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The main steam pressure of the turbine is high and its temperature is low, especially the water enters cylinder, resulting in a great axial thrust. So, the axial thrust will change greatly if the vacuum is low or the convection part is scaled. If the displacement is found to increase during operation of the unit, the turbine should be examined throughout, to listening to its inner sound and measure the vibration of bearing, and simultaneously to supervise the variation of the thrust pad and oil return temperature, in general, the babbitt temperature of the thrust pad is not more than 95℃ and the oil return temperature is not more than 75℃, while the temperature exceeds the permissive value, the load should be reduced to enable it to restore to the normal even if the displacement indication is not too much, if the indication exceeds the permissive value to cause the protective action to trip, the generator should be paralleled off and shut down. At this time if the protection does not act, it should be checked carefully. 2. Temperature of bearing pad The bearing of turbine rotates in the bearing pad, causing the temperature up of lubricating oil and bearing pad. Too high temperature of bearing pad will threaten the safety of bearing. The temperature of bearing pad can be supervised via supervision of the temperature up of lubrication during operation, in general, the temperature up of lubrication should not exceed 10 to 15℃, but it acts only as auxiliary supervision because the oil temperature lags behind that of metal and cannot show immediately the variation of bearing pad temperature. In order to make the bearing pad operating normally, the temperature of oil supplying to bearing pad is prescribed definitely, in general the specified temperature is within 35 ～ 45 ℃.

Section3

Inspection projects for the overhaul and mini-overhaul of units

In order to keep the unit can operate safely and economically for long time. Perform the mini-overhaul once each time when the unit has been in operation for 4 to 8 months accumulatively. Eliminate the defects occurred during operation in time and replace the damaged components. 1

Imperative inspection items for mini-overhaul 1.1 Check each support bearing and thrust bearing, and check whether there are the phenomenon of serious wearing, picking, crack, decrustation, etc. with the babbit alloy surface so as to treat in time. 1.2 Check main oil pump and tooth coupling of main oil pump to ensure the safe operation. 1.3 Take the static test of control system, oil spray test of emergency stopper and over speed test again after the mini-overhaul so as to confirm the reliable operation of control and security system.

2

Imperative inspection items for overhaul 2.1

Overall inspection 2.1.1

Check whether there are the phenomenon of leakage and erosion at the

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steam casing split; 2.1.2 Check and record the raise degree of rotor and each journal; Check and record the longitudinal and transverse level of bearing box and steam casing split; 2.1.3

Check and record the flow clearance and gland clearance;

2.1.4 Remove the connection bolts of coupling, check and record the change of alignment of coupling. 2.2

Rotor inspection 2.2.1

Clean the impeller and impeller blade and remove the scale.

2.2.2 Check the axial run-out of each part and run-out of end face. Check the cylindricity of journal and the run-out of end face of thrust disk. 2.2.3 Check whether there are the defects of cracks, erosion and damage, etc. at each part of impeller, blade and rotating part. Perform the static frequency test to the long blades. 2.3

Bearing 2.3.1

Check the clearance and tightening force of bearing.

2.3.2 Check whether there are the defects of wearing, decrustation and cracks etc, with babbit alloy. 2.3.3 Check the platinum resistance thermometer, and replace the damaged elements. 2.4 2.5

Steam casing, holding ring and diaphragm 2.5.1 Check whether there are cracks with the HP inner casing and outer casing; 2.5.2 Check whether there are changes with the center of steam casing. 2.5.3 Check the split clearance of upper half and lower half. 2.5.4 Check whether there are cracks with the holding ring and diaphragm, and whether there are deformation with the diaphragm. 2.5.5 Check the bolts, gland gaskets and the thermocouple, and replace the damaged elements.

2.6

Valve 2.6.1 Disassemble and check whether the components of main steam valve and control valve have become loosen or damaged; 2.6.2 Check whether there are any change with the stem and the clearance of sleeve. Check whether there are crack and bend with the stems; 2.6.3 Check whether the touch between the valve disk and valve seat is tight; 2.6.4 Check whether there are any plastic deformation with the tooth gasket.

2.7

Control system 2.7.1 Check whether there are any erosion, crack with the control and safe part sets. Check whether there are any changes occurring with the fitting clearance. 2.7.2 Check whether the geometrical size and rigidity of spring of emergency

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stopper meet the requirement of drawing. Check whether there are cracks with the spring surface. 2.7.3 Perform the static test, tightness test of valve, oil spray test of emergency stopper and over speed test to the control system, 2.8

Oil system 2.8.1 Check the installation clearance of bearing of main oil pump, impeller and tooth coupling; 2.8.2 Clean the oil cooler and check whether there area damages with the copper pipe. 2.8.3 Check the filter and clean the oil box and oil filter.. 2.8.4 Check and clean the fan and smoke exhaust system. 2.8.5 Check and clean the oil pipe line.

2.9

Vacuum system 2.9.1 Check the ejector 2.9.2 Check the tightness of vacuum system.

2.10

Exhaust system

2.10.1 Check each check valve of exhaust and the control system; 2.10.2 Check the check valve of high exhaust and keep the tight closing; 2.11

Drain system:

Check each drain pipe line and keep them expedite and have no block. 2.12

Centering support system: Check each part of centering support system to see whether they meet the designing requirements; Check whether the anchor bolts have become loose; Check whether there are gapped phenomenon between the pedestal and filling iron.

2.13 Monitor system: Check the axial displacement, expansion differentia, vibration, and each element of monitor system. Indicate and adjust over again. 2.1.4 Monitor the main steam pipe and reheat steam pipe line about the change of creepage in long term.

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Chapter 2 汽轮机自控维护 Section1

Instruction on Electric Monitoring System of Steam Turbine

0-1 Overview of system The electric monitoring protection system of steam turbine (see D300N-003005U) consists of five parts, namely: shafting (D300N-003006C), oil pressure / vacuum (D300N-003008D), temperature (D300N-003009D), auxiliaries (D300N-003010U) and ETS (D300N-003011E). The instruction describes the arrangement of measuring points for shafting, the various signals in oil pressure / vacuum and temperature parts related to normal safe operation of turbine, the control logic of various electric equipment and motors, as well as the emergency tripping system (ETS) of turbine. All setting values for various signals concerned in this instruction are based on the setting values in the “Instruction on start-up and operation of steam turbine”. This instruction can be used as basis of corresponding design by the Design Institute. 0-2 Shafting 1

General The parameters of shafting for the steam turbine-generator unit to be continuous monitored are speed, zero speed, overspeed, differential expansion of HP/IP and LP turbines, axial displacement, thermal expansion of HP/IP casing, eccentricity, shaft vibration and vibration at cover of bearing pedestal. Unless specified otherwise, the following parameters shall be monitored by the MMS6000 Serial from EPRO Company. The description will be made for speed, displacement and vibration respectively hereafter.

2

Speed monitoring

2.1 Speed and zero speed The monitoring function here is realized by two transducers, one of which is for speed and the other for zero speed. Corresponding the speed measuring range of 0～5000 rpm there are 4～20mA DC signal outputs from the monitoring module here to the DCS system for display. The zero speed relay contact signal is output as one of the starting-up signals for the automatic turning gear of turbine while the speed falls down to 2 rpm. 2.2

“2 out of 3” electric overspeed protection There are 3 transducers used for electric overspeed protection. When the speed “n” of

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turbine is equal to or greater than 3300r/min and the “2 out of 3” logic requirement is met, the overspeed protection signal is sent out to the relay to trip the turbine after logic processing by the ETS. 2.3

Tachometer at head of unit A domestic made CS-1 type magnetic resistance speed transducer and a domestic made WZ-3 type intelligent transient tachometer with digital indication are adopted for the unit. The tachometer possesses such functions as two level overspeed alarm, zero speed alarm, fast speed indication, max. speed storing and reproduction, self check and calibration etc. Two level overspeed alarm and the zero speed alarm are output through relay contact. The tachometer is mounted on the cover of front bearing pedestal at head of unit.

3

Displacement monitoring

3.1 Differential expansion of HP/IP and LP turbines These two monitoring channels here are provided with a transducer for each, which output the corresponding 4～20mA DC signals to the DCS system for display. The alarm relay is actuated and the alarm signal is sent out while the differential expansion value of HP/IP turbine ≥ +6mm or ≤ -3mm and the differential expansion value of LP turbine ≥ +14mm. The emergency relay is actuated and the differential expansion over limiting signal is sent out while the differential expansion value of HP/IP turbine ≥ +7mm or ≤ -5mm,and the differential expansion value of LP turbine ≥ +15mm. 3.2

Axial displacement There are two transducers used for axial displacement monitoring. Corresponding to the axial displacement measuring range of -2mm～+2mm , the 4～20mA DC signals are output from monitor to the DCS system for display. The alarm relay is actuated and the alarm signal is sent out while the axial displacement value≥ 0.6mm or≤-1.05mm . The emergency relay is actuated and the axial displacement over limiting signal is sent out to ETS for tripping the turbine while axial displacement value of both transducers ≥ +1.2mm or ≤-1.65mm.

3.3

Eccentricity and phase-shifting The eccentricity and phase-shifting measuring is conducted by a transducer for each. Corresponding to the eccentricity measuring range of 0～100μm , these monitors output the 4～20mA DC signals to the DCS system for display. The alarm relay of monitor is

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actuated to send out the alarm signal while the eccentricity of

shaft exceeds its original

value by 30μm. 3.4

Thermal expansion of HP/IP casing There are two monitoring channels for thermal expansion of casing located at both sides of HP/IP casing of turbine respectively to monitor the casing expansion related to the foundation of unit. Two domestic made 50mm absolute expansion transducers and a completed absolute expansion monitor are used for HP/IP casing expansion. Corresponding to the HP/IP casing expansion measuring range of 0~50mm, the respective channel of monitor outputs the 4～20mA DC signal to the DCS system for display. The alarm and emergency relays of monitor are actuated to send out the corresponding alarm signal while the casing expansion exceeds the setting value I and II respectively.

4 4.1

Vibration Shaft vibration In order to monitor the radial vibration of rotor related to the bearings, the 1#～6# journal bearings of unit are provided with two monitoring channels for shaft vibration respectively, one of which is in horizontal (X) direction and the other in vertical (Y) direction. That means there are total 12 channels. Corresponding to the shaft vibration measuring range of 0～400μm, each channel of monitor will output the respective 4～20mA DC signal to the DCS system for display. The alarm relay in respective channel of the monitor is actuated to output the alarm signal while the shaft vibration in any channel ≥ 0.127mm. The emergency relay in respective channel of the monitor is actuated to output the emergency alarm signal while the shaft vibration in any channel ≥ 0.25mm.

4.2 Vibration at cover of bearing pedestal In order to monitor the absolute vibration of bearing pad related to the free space, the 1#～ 6# journal bearings of unit are provided with a monitoring channel for vertical vibration at cover of bearing pedestal respectively. That means there are total 6 channels with total 6 speed transducers. Corresponding to the bearing pad vibration measuring range of 0～100 μm, each channel of the monitor will output the respective 4～20mA DC signal to the DCS system for display. The alarm relay in respective channel of the monitor is actuated to output the alarm signal while the vibration at cover of bearing pedestal in any channel

- 14 -

≥ 50μm. The emergency relay in respective channel of the monitor is actuated to output the emergency alarm signal while the vibration at cover of bearing pedestal in any channel ≥80μm 0-3 1

Oil Pressure /Vacuum

General The oil pressure/vacuum part of electric monitoring protection system of the steam turbine contains the destination of various signals related to the oil pressure and vacuum, as well as the various control logic of valves, oil pump and turning gear related to the oil pressure signal.

2

Tripping device for condenser low vacuum and lube oil low pressure There are 4 vacuum switches mounted in the tripping device for condenser low vacuum and 7 pressure switches in the tripping device for lube oil low pressure.

2.1

Signal output from tripping device for condenser low vacuum The vacuum switch PSB1 is actuated to output the alarm signal while the condenser vacuum becomes lower (i.e. the pressure in condenser P≥14.7kPa). Three vacuum switches PSB2～PSB4 are actuated to output the signal to the ETS for simultaneous alarm while the condenser vacuum becomes too low ( i.e. the pressure in condenser P≥ 19.7kPa).

2.2

Signal output from tripping device for lube oil low pressure The pressure switch PSA1 is reset to output the alarm signal while the oil pressure in lube line P ≤0.049MPa. Meantime the pressure switch PSA2 is also reset to output the signal for automatic starting the AC lube oil pump. The Pressure switch PSA3 is reset to output the signal for automatic staring the DC emergency oil pump while the oil pressure in lube line P≤0.0392MPa. Meantime three pressure switches PSA4～PSA6 are also reset to output the signal to the ETS for simultaneous alarm. It’s unavoidable for the turbine to come into the turning status after idling during shut-down. So if the oil pressure in lube line continuously falls down to P ≤ 0.0294MPa,the pressure switch PSA7 will be reset to output the signal for turning stop and for alarm at same time.

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3

Logic control of two oil pumps for main oil reservoir The turbine oil in protection system necessary for operation of steam turbine is supplied directly by the main oil pump mounted on the same shaft with turbine. The lube oil is supplied by the main oil pump through the oil injector. There are two oil pumps on the main oil reservoir. The AC lube oil pump is used to supply the oil for latching-on of the emergency tripping device during start-up of unit, as well as to supply the lube oil to the bearings, turning gear and oil jacking device during start-up and shut-down of unit instead of the oil injector at outlet of main oil pump, or to supply the lube oil to the above mentioned areas with the oil injector at outlet of main oil pump in parallel while the oil pressure in lube line P ≤0.049MPa during operation of unit. The DC lube oil pump is used to supply lube oil to all bearings of unit with the AC lube oil pump together while the oil pressure in lube line P ≤0.0392MPa (at this moment the unit has received the shut-down signal) or supply lube oil to all bearings of unit independently while the AC lube oil pump is out of work due to trouble, thus to make the unit coming into turning status after idling.

3.1

Logic control of AC lube oil pump 3.1.1 Automatic mode There is a “Auto/Manual” selection pushbutton for AC lube oil pump in the DCS system and mounted on the block control panel in central control room. In case the pushbutton is selected in “Auto” mode, the AC lube oil pump will be put into operation automatically while the oil pressure at outlet of the main oil pump falls from the normal value down to P ≤1.8MPa, or the oil pressure in lube line falls down to P ≤0.049MPa, or the speed of turbine falls down to n ≤2850 r/min during operation of unit. Unless the electric failure happens with its motor, the AV lube oil pump will keep operation after automatic starting until change- over to the “Manual” mode. And only in this case the pump can be stopped with the “stop” pushbutton on UCP. There are an oil draining solenoid valve 25YV and a pressure switch PSA2 for simultaneous test of AC lube oil pump mounted after the orifice in sampling pipe for lube oil pressure of the lube oil low pressure tripping device. After pressing down this simultaneous test pushbutton, the solenoid valve 25YV is energized to drain the oil , then the pressure switch PSA2 is reset to start the AC lube oil pump automatically through the contact while the oil pressure falls down to P ≤0.049MPa.

- 16 -

3.1.2 Manual mode In case the pushbutton in DCS is selected in “Manual” mode it’s possible to start or stop the AC lube oil pump any time by means of the start/stop pushbutton in DCS. The requirement for regular test of this pump can be also met by this mode. 3.1.3 Signal The DCS is provided with the signal lights for “Auto” mode, start and stop of this pump. Also the alarm signal will be sent out while any electric trouble happens with the motor 301M of this pump. 3.2

Control logic of DC emergency oil pump The DC emergency oil pump is put into operation only while the failure happens with the turbine. The DCS is provided with only the pushbuttons for start, stop and simultaneous test for this pump instead of the “Auto/Manual” mode selection pushbutton. In addition, the signal light for “start” and “stop” of this pump must be provided. The emergency oil pump will start automatically while one of the following situations occurs during operation of unit: a)The AC lube oil pump fails to automatic start due to under- voltage of control power source for its motor or electric failure occurring with its motor while the oil pressure in lube line falls down to P ≤0.049MPa; b) There are an oil draining solenoid valve 26YV and a pressure switch PSA3 for simultaneous test of DC emergency oil pump mounted after the orifice in sampling pipe for lube oil pressure of the lube oil low pressure tripping device. After pressing down this simultaneous test pushbutton, the solenoid valve 26YV is energized to drain the oil , then the pressure switch PSA3 is reset to start the DC emergency oil pump automatically through the contact while the oil pressure falls down to P ≤0.0392MPa. The DC emergency oil pump is un-necessary to be provided with any protection measures, because it’s the last supplier of lube oil to the unit and to prevent the bearing pad of unit from burning out will be much valuable comparing with protecting the relative cheaper DC motor. For this reason only an alarm signal will be sent out while electric failure happens with the motor 302M of pump.

4

Control logic of oil jacking pump There are two oil pumps for the oil jacking device, one of which is for stand-by while the other one is being in work. The oil jacking pump is used to establish high pressure to force the shaft journal

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lifting-up during start-up and shut-down on unit, thus to create the necessary condition for turning the unit.

4.1

Automatic mode The DCS is provided with a selection pushbutton “Auto/Manual” for 1#～2# oil jacking pumps. In case this pushbutton is selected in “Auto” mode, both pumps are under automatic control. The “Auto” mode is used during shut-down of unit. As soon as the turbine suffers tripping, its speed falls from 3000r/min down to 1200r/min and the 1# oil jacking pump receives the start signal first and time counting begins at same moment. If the oil pressure at inlet of 1# oil jacking pump is normal(P≥0.1MPa), the pump will start automatically. If 1# oil jacking pump fails to start within 5 sec. due to electric trouble, 2# oil jacking pump will start automatically on the premise of the oil pressure at its inlet normal (P≥ 0.1MPa). In addition, if 1# oil jacking pump becomes out-of work due to electric trouble during operation or due to oil pressure at its outlet lower than setting value(P≥0.1MPa)during operation, 2# oil jacking pump will also start automatically on the premise of the oil pressure at its inlet normal and vice versa. This kind of logic can meet the requirement for both pumps serve for stand-by each other. After automatic starting, the oil jacking pumps will keep operation. They will stop automatically only when the speed of turbine becomes higher than 1200r/min, or oil pressure at outlet of pump is lower than setting value, or electric trouble happens with its motor. Alternately, they will stop by means of the “Stop” pushbutton after change-over to the “Manual” mode.

4.2

Manual mode In case the pushbutton for oil jacking pump is selected in “Manual” mode, it’s possible to start or stop the oil jacking pump ant time as required by means of the start/stop pushbuttons in DCS. One of these two oil jacking pumps is able to start while the oil pressure at its inlet is normal and the other pump is not in working status. Any of these two pumps is able to start by means of pushbutton only when the other pump being in operation is out of work. It’s not allowed to put two oil jacking pumps into operation at same time.

4.3

Signal The DCS is provided with the signal lights for “Auto” mode, start and stop of these two oil jacking pumps. The alarm signal will be sent out while electric trouble happens with the

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motors 303M, 304M of pumps. The alarm signal will be also sent out while the core of twin-shell oil filter or plate-type oil filter becomes plugging. 5

Logic control of turning gear Before normal turning the lube oil line must work normally(P≥ 0.08MPa). The transmission of turning gear is realized in following way: the motor transmits the movement to the swinging pinion after speed reducing, then the pinion is engaged with the gear rim on the rotor (engagement completed) to rotate the rotor. The procedures of tuning during start-up of the unit are as follows:

a)

Energize the solenoid valve to lead the pressurized oil in for relieving the interlock of swinging oil cylinder first, and moving the swinging cylinder with pinion in direction of the gear rim on rotor then.

b) Start the motor and keep it running while the swinging pinion is engaged with the gear rim on rotor (engagement completed). 5.1 Automatic mode The automatic turning mode is used during shut-down of unit. In case the selection pushbutton “Auto/Manual” for turning gear on the local control panel is selected in “Auto” mode, the above-mentioned two procedures a) and b) will be conducted automatically while the oil pressure in lube line and oil jacking line is normal and the speed of turbine falls from the rated value down to zero (n ≤2r/min,contact signal sent by ESI). Namely energize the solenoid valve first, start the motor for tuning after 30 sec. then. The purpose of time delay is to ensure sufficient time for swinging pinion to complete the engagement with the gear rim on rotor. The motor for turning will keep running while the turning gear completes engagement in place (the solenoid valve is de-energized at this moment). The motor for turning will stop automatically while the oil pressure in lube line is too low (P ≤0.0294MPa) or electric trouble happens with the motor. 5.2 Manual mode In case the selection pushbutton “Auto/Manual” for turning gear on the local control panel is selected in “Manual” mode, it’s possible to control start and stop of the turning gear by means of the start and stop pushbuttons on the local control. There are two kinds of manual mode, one of which is realized by the signal of pushbutton “TG start” on the local control panel instead of the zero speed signal

and the other is realized by the

- 19 -

pushbuttons for “TG in” and “Motor start” respectively. In case the latter manual mode is used, the solenoid valve is energized after pressing down the “TG in” pushbutton, then is de-energized until reaching the “engagement completed” or the “stop” pushbutton is pressed. The motor is able to re-start through pressing the “motor start” pushbutton only after 30 sec. while the oil pressure in oil jacking line is normal.

A motor emergency start pushbutton is provided specially for the possibility to make the unit coming into turning in the emergency status such as the oil pressure in oil jacking line abnormal. In addition, for convenience the local operation can be realized for such pushbuttons and lights as “TG start”, “TG in”, “TG stop”, “motor start”, “motor emergency start” and “disengagement” etc. The “TG stop” pushbutton on the local control panel is able to be effective after pressing, no matter the turning gear is being in “Auto” or “Manual” mode. It’s necessary to press the “TG stop” pushbutton first while the turning cut is required. Then press the “disengagement” pushbutton after falling down the speed of motor of turning gear to have the motor rotating backward for swinging pinion disengagement. Nothing will happen through directly pressing the “disengagement” pushbutton during turning process. The rolling-up of turbine is realized in turning status. When the speed of turbine reaches a certain value, the swinging pinion will be disengaged automatically by the action of increased centrifugal force of gear rim on rotor. The motor of turning gear will stop automatically while the swinging pinion is in the disengagement status. The local control panel is provided the corresponding interface for remote operation of the turning gear (from DCS). 5.3

Signal The local control panel is provided with such signal lights as “Auto mode”, “Turning completed”, “disengagement completed” and “turning on” etc. An alarm signal will be sent out while electric trouble happens with the motor 307M of turning gear.

6

Various pressure signals for steam turbine Various signals for steam pressure and oil pressure at turbine side are shown in the Fig. All measurement instruments for these pressures shall be supplied by the project owner itself.

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0-4 Temperature 1

General The temperature part of the electric monitoring protection system of steam turbine contains the various temperature related measures taken to ensure the normal start-up and operation of turbine proper and its corresponding auxiliaries, as sell as the various temperature measuring points supplied by the turbine manufacturer.

2

Logic control of motor-driven valve for LP exhaust water spray device There is a motor driven valve 401MV provided for LP exhaust water spray device. As required the water comes from the outlet of condensate pump and sprays out of the nozzles in the both LP exhausts at GOV. and GEN. Ends through the motor-driven valve, the duplex screen and the duplex manual throttling valve successively. The duplex screen is provided with the differential pressure transducer for plugging, one of screen is for working and the other for stand-by. Logic control of motor-driven valve of water spray device a) The DCS is provided with a “opening” pushbutton and a “closing” pushbutton for the valve. Both these buttons will become effective only when the “Auto/Manual” selection button for the valve is in the “Manual” position. b) In case the “Auto/Manual” button for the valve is selected to the “Auto” mode, the motor driven valve will fully open automatically while the temperature at any of two measuring points for exhaust steam in LP hood t≥ 80℃. And the valve will be fully closed while the temperature at both measuring points is t ≤65℃. c) There is an interlock between opening and closing of the valve, namely an interlock between rotating forward and backward of the valve driven motor. d) The stop signal for valve opening will be sent out only when the full opening limit switch of the valve is not actuated, or the full closing limit switch is not actuated but the torque limit switch at opening side is actuated, or electric trouble happens with the valve driven motor. e) The stop signal for valve closing will be sent out only when the torque limit switch at closing side is actuated, or electric trouble happens with the valve driven motor. f)

The signal will be sent out by the corresponding limit switch to the DCS system for

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display while the full opening and closing of the valve is completed. g) There is an alarm signal appearing on DCS for display while electric trouble happens with the valve driven motor. 3

Control logic of turbine proper and its auxiliary systems 3.1 Control logic of motor driven valve 402MV before heating steam inlet header for inter-space between two shells of casing a) During cold start, speeding –up and loading of steam turbine, the said valve shall be open according to the temperature difference of casing metal and the differential expansion between HP/IP casing and rotor and closed while the above mentioned temperature difference and differential expansion become stable after warming. So the UCP is provided with only an opening button, a closing button and an opening/closing stop button for the valve. The valve will be open only under such condition that the drain valve of heating steam inlet header for inter-space between two shells of casing has been open already. b) The stop signal for valve closing will be sent out only when the torque limit switch at closing side is actuated, or electric trouble happens with the valve driven motor, or the stop button is pressed. c) The signal will be sent out by the corresponding limit switch to the DCS system for display while the full opening and closing of the valve is completed. A resistance signal will be sent out by a potentiometer to reflect the valve position status while the valve is at the middle position. d) There is an alarm signal appearing on DCS for display while electric trouble happens with the valve driven motor. 3.2 Control logic of pre-warming of casing The pre-warming steam enters into the casing through two motor driven valves in series, the valve 403MV close to the casing is used as block valve and the other one 404MV as throttling valve. When the pre-warming is required, the block valve is fully open automatically by the signal from the DEH and the throttling valve is slowly open by the operator with remote button according to the HP casing metal temperature. In order to stop the pre-warming, the DEH will send out the closing signal to close the block valve and throttling valve at same time. So the UCP is provided with a “Auto/Manual” selection button —— an

- 22 -

opening button, a closing button and an opening/closing stop button for two motor driven valves respectively. The requirement for temperature raising rate during pre-warming can be met by means of adjusting the reverse warming valve and drain valves at various sections to ensure the temperature difference of casing wall and the differential expansion within the allowable range. There are two control modes for the casing pre-warming: “stop” and “manual in”. See points b), c) and d) in above item 3.1 for the corresponding signals of opening, closing and stop for these two valves. The motor driven throttling valve can be open only after the motor driven block valve is open. 3.2.1

Automatic mode

In case the “Auto/Manual” selection button for motor driven block valve and motor driven throttling valve on the UCP is in “Auto” mode, the opening and closing of the former valve and the closing of the latter valve will be controlled by the signal from the DEH. The opening of the latter valve can not be controlled automatically. 3.2.2 Manual mode In case the “Auto/Manual” selection button for motor driven block valve and motor driven throttling valve on the UCP is in “Manual” mode, the opening of both valve can be controlled to meet the requirement for temperature raising rate and differential expansion during casing pre-warming by means of the opening button, closing button and stop button on the UCP. 3.3 The emergency relieve valve BDV is of the pneumatic closing type and controlled by the air control solenoid valve TBSV. When the pre-inlet valve of 1＃or 2＃ IV is fully open, the corresponding servomotor leaves from full closing position and the valve TBSV is energized to close the valve BDV by the pneumatic force. In case the pre-inlet valve is not in full opening position, the valve TBSV is de-energized to open the valve BDV due to the compressed air source cut. The valve BDV is provided with position switches for opening and closing to send out the signal to DCS for display. 3.4 Control logic of vent valve There is a vent valve VV mounted in the HP exhaust steam pipe to keep vacuum of HP casing with condenser together for preventing the HP casing from overtemperature caused by windage effect during start with IP turbine or operation with lower load.

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The pneumatic solenoid valve VSV to operate the opening/closing of the vent valve VV is controlled by the contact signal of “open VV valve” from the DEH. The VV valve is open while the signal contact is closing and is closed while the contact is open. The following procedures have been realized by the logic of DEH: a) The VV valve is closed during pre-warming and holding period of HP casing. b) The VV valve is open during start with IP turbine and is closed until change-over between HP and IP casings. It should be emphasized that the VV valve for this unit is located downstream the exhaust of HP casing, and shall not be open with closing the GV to prevent the unit from overspeed. 4

Control logic of demisting fan of main oil reservoir

There are two demisting fans mounted on the main oil reservoir, one of which is for normal working and the other one for stand-by. The DCS is provided with start and stop buttons for the demisting fans. The 1# fan shall start and keep operation before the oil system of turbine putting into operation. The other fan is able to start manually while the fan being in operation is out of work due to trouble. The demisting fans are provided with local start and stop lamps. Also an alarm signal will be sent out to UCP and DAS while electric trouble happens with the fan driven motor. 5

Control logic of heater for main oil reservoir

The main oil reservoir is provided with 6 electric heaters which is divided into two groups composed of three heaters for each in three-phase 380V star-connected circuit. The UCP is provided with a start button, a stop button, a power-on button and a power-off button for each group of heaters. In addition, an alarm signal will be sent out to DCS while trouble happened with the heater. The “power-on” lamp turns on while any of three heaters in same group is energized. But the “power-off” lamp turns on only when all three heaters in same group are de-energized. The condition for putting heater into operation is: the oil level in main oil reservoir normal (not in lower level), the AC lube oil pump or the DC emergency oil pump being in work and the oil temperature in oil reservoir low. In order to avoid degradation of turbine oil quality due to overtemperature on surface of heater, the thermal resistance is provided for the surface of heater. The heating process

- 24 -

will be intercepted while the temperature on surface of heater is ≥140℃. In addition, the heating process will be also intercepted while the oil temperature in oil reservoir is ≥35 ℃, or electric trouble happens with heater (e.g. actuation of protection switch due to overload or short circuit). 6

Various temperature signals of steam turbine

Fig.13～17 show various temperature signals for bearing metal and drain oil from bearings of turbine in detail and illustrate the type and application of thermal element. It should be noted that the Dongfang Steam Turbine Works is responsible only to provide the primary thermal element in its supply scope. The project owner shall be responsible for the primary thermal element including the following transducer in its scope.

0-5 Auxiliaries 1

General The auxiliaries part of electric monitoring protection system for steam turbine contains the control logics for various motor-driven valves, solenoid valves and other motors in draining system, pneumatic system for extraction check valves and HP exhaust check valves and self sealing system of turbine proper.

2

Control logic of pneumatic valves in draining system for turbine proper During start-up, shut-down and operation with lower load, or under abnormal operation condition of turbine, any condensate in turbine proper and piping shall be drained through motor-driven drain valves to avoid rotor bending or components damage caused by the water entering into the casing. There are total 13 motor-driven drain pumps in draining system of turbine, 7 from which are at HP section (501PV～507PV in logic diagram),4 at IP section (508PV～511PV) and 2 at LP section (512PV, 513PV). All these drain valves are controlled by their own air control solenoid valves(501SV ～ 513SV)respectively for opening and closing. The pneumatic actuating system of these drain valves is composed of air control solenoid valve, diaphragm-type actuator, and limit switches for full opening and full closing of valve. The DCS is provided with a “Auto/Manual” selection button, a opening button and a closing button.

2.1 Automatic control mode for pneumatic valves In case the “Auto/Manual” selection button for any drain valve on the DCS is in the “Auto”

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mode, the said drain valve is under automatic control for its opening and closing. In automatic mode, the drain valve will be open while the oil switch of generator changes from closing to opening, because the tripping of oil switch leads to de-energizing of the air control solenoid valve, thus to cut the air source for pneumatic drain valves. In automatic mode, as soon as the load of generator rises to 10%, 20%, 30% of rated value, the DEH will send out signals to energize the air control solenoid valves for HP, IP and LP sections successively for closing the drain valves at these sections by the action of compressed air force. And when the load of generator falls down to 30%, 20%, 10% of rated value, the DEH will send out signals to de-energize the air control solenoid valves for HP, IP and LP sections successively for opening the drain valves at these sections due to air source cutting. 2.2 Manual control mode for pneumatic valves In case the “Auto/Manual” selection button for any drain valve on the DCS is in the “Manual” mode, the said valve is under manual control. In this case the said drain valve can be open or closed by means of the local opening button or closing button for this valve. 3

Control logic of check valves in pneumatic system of extraction and HP exhaust check valves The steam turbine is provided with check valves at all extraction ports with the purpose to avoid overspeed caused by the steam in feedwater heaters returning back into the casing through extraction piping due to pressure reducing during load rejection. And the check valves mounted at HP exhaust are used to avoid the low temperature steam in reheater of boiler returning back to HP casing during hot start and load rejection. There are total 10 check valves (514PV～521PV in logic diagram) at extraction ports and 2 check valves 522PV, 523PV in logic diagram) at HP exhaust. The “free state” of extraction check valve is defined as it can be open while the working medium flows forward and be closed while the working medium flows backward. The DCS is provided with an “Auto/Manual” selection button, a manual opening button and a manual closing button for each check valve. Also the DCS is provided with the corresponding lamps to indicate the check valves being in “Auto” mode. In addition, the DCS is also provided with signal lamps to indicate the extraction check valves being in closing status and two check valves at HP exhaust being in opening status as well as the corresponding alarm signals.

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3.1 Automatic control mode of extraction check valves In case the “Auto/Manual” selection button for extraction check valves on the DCS is in the “Auto” mode, the said check valves are under automatic control for its opening and closing. 3.1.1 Automatic control mode of extraction check valves leading to feedwater heaters There are total 8 extraction check valves leading to feedwater heaters, namely: a)

#1 extraction check valve 514PV leading to #3 HP heater JG3.

b) #2 extraction check valve 515PV leading to #3 HP heater JG2. c)

#3 extraction check valve 516PV leading to #1 HP heater JG1.

d) #4 extraction check valve 517PV, 518PV leading to deaerator (CY and house service steam). e)

#4 extraction check valve 519PV leading to the BFPT.

f)

#5 extraction check valve 520PV leading to #4 LP heater JD4.

g) #6 extraction check valve 521PV leading to #3 LP heater JD3. 3.1.1.1

Any of above mentioned extraction check valves will be open automatically while the following conditions are met at same time:

a)

The corresponding heater (deaerator) has be put into working.

b)

The water level in corresponding heater (deaerator) is normal.

c)

The oil switch of generator didn’t change from closing to opening.

d)

The main stop valve is full open.

3.1.1.2 Any of above mentioned extraction check valves will be closed automatically while one of following conditions is met: a)

The oil switch of generator trips (from closing to opening).

b)

All electric tripping signals are cut or the main stop valve is fully closed.

c)

The water level in corresponding heater (deaerator) is too high.

d)

The corresponding heater (deaerator) in cut manually.

3.1.2 Automatic control mode of extraction check valve for house service and BFPT This is the #4 extraction check valve 519PV for BFPT. 3.1.2.1

The above mentioned extraction check valve will be open automatically

while the following conditions are met at same time: a)

The oil switch of generator didn’t change from closing to opening.

b) The main stop valve is open.

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3.1.2.2

The above mentioned extraction check valve will be closed automatically

while one of following conditions is met a)

The oil switch of generator trips (from closing to opening).

b) All electric tripping signals are cut. c)

The main stop valve in fully closed.

The #4 extraction check valve 519PV for BFPT will be also closed automatically while the tripping signal is sent out by the BFPT. 3.2 Automatic control mode of two HP exhaust check valves In case the “Auto/Manual” selection button on DCS for two HP exhaust check valves is in the “Auto” mode, these two check valves will be under automatic control for opening ( in free state) and closing (forced closing). When the main stop valve is open, two HP exhaust check valves will be open automatically and come into free state. These two check valves will be closed while the mode of start with IP turbine is selected and the change-over of valves is not performed at same time, or all electric tripping signals are cut or the main stop valve is fully closed. 3.3

Manual control mode of check valves

In case the “Auto/Manual” selection button on DCS for any check valve is in the “Manual” mode, the said check valve will be under the manual control for its opening and closing. In this case the said check valve can be open or closed by means of the local opening button or closing button respectively. 4

Control logic of motor-driven block valves in self-sealing system of turbine There are total 10 motor-driven block valves in self-sealing system of turbine, namely the block valve 502MV, regulating valve 504MV and bypass block valve 503MV of auxiliary steam supply in control station for auxiliary gland steam; the block valve 505MV, regulating valve 507MV and bypass block valve 506MV of main steam supply in control station for main gland steam; the overflow regulating valve 508MV and bypass block valve 509MV in control station for gland overflow; as well as the block valve 510MV, regulating valve 511MV of cooling water supply for LP gland steam desuperheater. 4.1 Automatic control mode of motor- driven block valve The DCS is provided with the “Auto/Manual” selection button only for the auxiliary steam supply valve in control station for auxiliary gland steam. In case the selection button is in

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the “Auto” mode, the said valve will be under automatic control. Under various starting conditions of turbine, the auxiliary gland steam supply valve will be open automatically while the steam temperature before the said valve is normal (210℃ ≤t≤260℃), or the oil switch of generator changes from closing to opening and the steam temperature before auxiliary gland steam supply valve t≥260℃ at same time. The said valve will be closed automatically while the oil switch of generator changes from closing to opening and the steam temperature before auxiliary gland steam supply valve t96%)

Hydrogen pressure is 210cu.m

1~1.5h

increased to 0.3MPa carbon dioxide

Hydrogen

150cu.m

4~5h

(purity>96%)

2.2

Operating principle of the hydrogen system: Hydrogen is inputted to gas control station from the hydrogen supply

system through double bus duct and is delivered to the generator after straining out solid impurities by a filter and removing moisture though a gas dryer。 Two sets of automatic hydrogen make up device will be provided on the gas control station, one is solenoid valve, when the hydrogen pressure in the generator is reduced to the lowest limit of a set value, the contact in the pressure controller is turned on and the solenoid valve is opened, The hydrogen enters the generator through the solenoid valve. When the hydrogen pressure in the generator increases to the highest limit of a set value, the contact in the pressure controller is turned off and the solenoid valve is closed and filling hydrogen is stopped. Another is a pressure reducer, it's the output pressure value is sets the rated hydrogen pressure value of the generator. Therefore, as long as the hydrogen pressure in the generator is reduced, hydrogen will occur at the output terminal of the pressure reducer until the hydrogen pressure in the generator is resumed to the rated value. A safety valve is installed on the gas control station. When the hydrogen pressure in the generator is excessively high, hydrogen pressure can be relieved.

Parts of hydrogen in the generator enter the hydrogen dryer along the pipeline under the action of the fan. The dried hydrogen returns to the suction zone of the fan in a continuous circulation so that the hydrogen moisture in the generator is reduced. Similarly, the hydrogen flowed in the hydrogen purity analyzer is also conducted by the action of the fan. The hydrogen purity in the generator can be continuously analyzed by the analyzer, and 4～20mA signals will be given out . Four oil/water monitors are furnished in the hydrogen control system. They separately are installed on the CO2 pipeline and the bottom of the generator. When oil or water enters the generator and over setting valve, the floats in proper will be rise and turned on electric enunciator circuit and alarm signals will be given out. When the generator and the gas pipe are required to be air tightness tested with compressed air, the compressed air is inputted into the generator through a valve on the gas control station after being dried by the gas dryer. After the air tightness test is qualified, the compressed air is drained to the outside of the power house. It is prohibited to directly filling hydrogen (or air) into the generator when the generator is filled with air (or hydrogen) so as to avoid the formation of explosive air-hydrogen mixture. Therefore, gas replacement must be conducted for the generator and hydrogen pipeline system. CO2 gas or N2 gas in a standard gas bottle may be fed into the generator from the generator bottom along piping after being reduced from the maximum pressure of 15MPa to 0.2~0.5MPa through the pressure reducer. Thus the replaced air (or hydrogen ) is drained to the outside of the power house along the hydrogen piping of the generator. 2.3 About the gas displacement of the generator 2.3.1 After the pipeline installation ( or maintenance ) for the generator, and the air-tightness test is qualified, gas replacement can be conducted, the way is that inert gas, such as CO2 or N2 can be used to drive out air (or hydrogen ) in

the generator and then the inert gas is driven out from the machine with

hydrogen, so as to prevent hydrogen and air from contacting directly during

gas replacement, therefore, no explosive hydrogen-air mixture can be formed, this process of gas replacement is called the intermediate medium replacement way. Prior to hydrogen charging, CO2 gas ( or N2 gas ) is used to drive out air from the generator, after CO2 gas content in the generator is over 85% ( N2 gas content over 95% ), and then CO2 gas ( or N2 gas ) shall be driven out by hydrogen, finally, then the generator is charged with hydrogen. During hydrogen discharging, CO2 gas ( or N2 gas ) is carried to the generator to drive out hydrogen, after CO2 gas content is over 95% ( N2 gas content

over

97% ), compressed

air

can be fed into the generator to

drive out CO2 gas ( or N2 gas ), after CO2 gas (or N2 gas ) content is lower than 15%, the compressed air introduced to the generator will be stop. 2.3.2.The following points shall be noticed during intermediate medium replacement. 2.3.2.1

Hydrogen, compressed air and intermediate gas (CO2 gas is

preferable )must be introduced to the special inlet on the gas control station and they cannot make a mistake. 2.3.2.2 Gas flow speed should be properly controlled to prevent producing a heat source in variable diameter of pipe due to excessively high gas flow speed. 2.3.2.3

A given gas pressure shall be stored during all process of gas

replacement in the generator (the pressure is between 0.01~0.03MPa ). 2.3.2.4 Fire is strictly prohibited near the site or the orifice of discharged pipes. 2.3.2.5

Correct and comprehensive sampling points are required, during the

process of gas replacement frequent discharging work shall be done for gas displacing pipe and dead zones where gas can not be easily circulated such as gas dryer, seal oil tank sample shall be taken from all these points, the test results shall be in accordance with the requirement. 2.4 2.4.1

Main equipment of hydrogen control system : Gas control unit and the carbon dioxide standard manifold bar are

designed on shape of closing to wall type. 2.4.2

Two refrigerating hydrogen dryer .

2.4.3

Hydrogen analyzer .

2.4.4 2.5

Gas dryer is adsorption type dryer . Points of attention for installation :

2.5.1 All pipes are all seamless steel tube, the inner wall of tube must be cleaned. 2.5.2 Sealed material of flanged coupling must use oil proof rubber plate thicker than 3mm. 2.5.3 The hydrogen-side pipe of the gas control unit must be done gas -tight test independently. Testing pressure is the same as that of hydrogen-storing equipment, usually 1MPa. The other equipment and gas pipe better to be done gas-tight test independently, testing pressure are about 0.6MPa, so shorten time of looking for leakage. 2.5.4

Drying agent in dryer must be rightly placed before gas-tight test.

2.5.5 All the gauges and instrument of this unit must be recalibrate before installation. 2.6

Regulating and test of hydrogen system. After installing, the hydrogen system should be regulated and tested on

the working field as follows. 2.6.1 Setting of safety valve There is a safety valve on the gas control unit. Its released pressure is adjusted by spring. The released pressure of safety valve of this unit is set to 0.36MPa. Setting will be doing on the unit’s pipe. Firstly, carrying into H2 gas or compressed air from the pipe bus valve of carbon dioxide standard manifold. when the gas pressure rises to 0.36MPa, by turn adjusting nut on the safety valve, the safety can open automatically and released pressure in pipe. When the pressure falls to 0.3MPa, close the safety valve. When pressure is 0.28MPa, you can check leakage by using soap water. The Safety valve must avoid leakage condition. 2.6.2

Setting of the pressure controller

The pressure controller is a switch that opens on circuit's pressure changing. You can open and close hydrogen makes up solenoid valve by it, at the same time it can indicate low pressure in the generator.

When regulating

pressure controller, carrying into compressed air, the pressure gauge indicate

0.28MPa, then release lock of pressure controller, turn setting button, make indicating needle point at pressure valve needed, that is point of 0.28MPa, at this time, switch should be closed, if electric return circuit is energized, the solenoid valve should be energized and open. Then raise pressure to 0.3MPa, the switch should be turned off. Electric return is switch off, the solenoid valve is closed. It should be calibrated twice at least. If there is no abnormal condition, then lock out after one more recalibration, if there is no abnormal condition, you can finish regulating work. 2.6.3 Installation and regulation of hydrogen analyzer and oil/water monitor refer to manual provided by its factory. 2.7 The operation and maintenance of the hydrogen unit. 2.7.1 The drying agent in dryer should be changed at regular interval. Especially for unit with high moisture lubricant, it should be changed frequently, drying agent should be changed at first time three months after it is put into operation. Therefore changing time depends on situation, but not more than four and a half month. 2.7.2

Instrument and gauge should be calibrate at regular interval, the

pressure controller and the safety valve also should be set at regular interval. It is recommend to set every 6 months.

Section3 3.1

Seal Oil control system(See the seal oil control system diagram)

General The turbine lubricating oil for generator seal ring is named seal oil

according its purpose. Seal oil system supplies oil to seal ring of the generator, and the pressure of oil greater than the pressure of hydrogen to prevent hydrogen in the generator leak out from the gap between seal ring and rotation shaft, at the same time prevent oil pressure too high to a lots oil enters the generator. Seal oil system is decided according the type of the seal ring. The double ring type seal oil system and the single ring type seal oil system are main types. This exposition is adequate for single ring type seal oil system designed and made by DFEM.

3.2 Main technical parameters: Seal oil: same as lubricating oil Inlet oil temperature of the rings: 25℃～50℃ Outlet oil temperature of the rings:≤70℃ Differential pressure between in the rings and hydrogen in generator: 0.056±0.02Mpa seal ring oil quantity: turbine side:92l/min; excitation side:92l/min. 3.3 Operating principle: Seal oil system includes the main circuits as following: regular operation circuit、emergency operation circuit、emergency seal oil circuit (the third seal oil source). 3.3.1 Regular operation circuit: Bearing lubricating oil pipe → vacuum tank →main seal oil

pump (or

pump for stand-by )→seal oil filter→differential pressure regulating value→ seal ring of the generator→hydrogen side drain (air side drain mixed with bearing lubricating oil drain flow to air detraining section directly)→ oil drain enlargement section →float trap→air detraining section→bearing lubricating drain→turbine main oil tank 3.3.2 Emergency operation circuit: Bearing lubricating oil pipe →emergency seal oil pump (D.C pump) → differential pressure regulating valve → seal oil filter → seal ring of the generator→hydrogen side drain

(air side drain mixed with bearing lubricating

oil drain flow to air detraining section directly)→seal oil drain enlargement section →float trap—→air detraining section→bearing lubricating drain→ turbine oil tank . 3.3.3 emergency seal oil circuit: (third oil source) This circuit is operated when both main seal oil pump and D.C pump were stopped , the bearing lubricating oil can be used as seal oil for sealing the hydrogen ,at this time the hydrogen pressure must be decreased to

0.05MPa~0.02MPa. 3.4

Main equipment of seal oil control system:

3.4.1 seal oil drain enlargement section The hydrogen side drain pipe of the turbine side and the excitation side connect to drain enlargement section, in which the drain oil can be spread out and eliminated hydrogen. 3.4.2 float trap The drain oil of hydrogen side pass by enlargement section then enters float trap, which purpose is eliminate the hydrogen in oil any more. 3.4.3 Air detraining section Air side drain mixed with bearing lubricating oil drain flow to air detraining section, gas in oil is drained to outside of building through pipe, lubricating oil flow back to turbine main oil tank

.

3.4.4 seal oil supply station It consist of the following main equipments assembled on a base plate: two main AC pumps, one emergency seal oil pump, vacuum device, one differential pressure regulating valve, some instruments and valves. 3.4.4.1 Vacuum device The vacuum tank, vacuum pump and recirculating pump are the main equipments of vacuum device. they are oil purifying equipments of the seal oil system for single-ring type. 3.4.4.1.1

Vacuum tank(refer to 3.4.5)

3.4.4.1.2

Vacuum pump works continually to keep high vacuum in the

vacuum tank, the air,and moisture in oil can be drained out at the same time. 3.4.4.1.3

Recirculating pump works continually, so the oil in vacuum tank

come into a repeating local circulation through pipe, and it can be clean much more. 3.4.4.2 Oil pump There are two main seal oil pump ,one for regular and one for stand-by .They are both driven by A.C motor ,so they are named A.C oil pump. One emergency seal oil pump will start up when main oil pumps are

stopped in trouble .It is driven by D.C motor, so it is named D.C oil pump. 3.4.4.3 Differential pressure regulating valve The regulating valve regulates oil pressure which enters seal ring automatically, and it follows the change of the gas pressure in generator automatically in order that the differential pressure between oil and hydrogen should be maintained at needful range. 3.4.4.4 Seal oil filter Seal oil filter is fitted the outlet pipes of the differential regulating valve, it is used for filtering solid impurity in the seal oil. 3.4.5 Vacuum tank When A.C seal oil pump is works normally, bearing lubricating oil enters vacuum tank on and on, gas and moisture is separated from oil in vacuum tank, and drained out through vacuum pump and pipe , therefore the oil which enter seal ring can be cleaned and also air or moisture can be prevented to pollute hydrogen in the generator. There is a float valve in vacuum tank. its float ball rise or down following oil level high or low to regulate the valves open-close angle, thus it can control the speed for makeup oil

and

oil level.

Liquid level annunciator is a main adjunct too. oil level will be seen through it and it will send alarm signal when oil level high or low. 3.5

Regulating and setting of seal oil system

3.5.1 The setting of the pressure controller When the outlet oil pressure of oil pump is low to 0.54Mpa,the pressure controller(PCL-201) delay 3~5 seconds to start standby oil pump. If PCL-201 turn off in low pressure condition and A.C standby pump cannot maintain normal work pressure,then D.C pump control circuit be passed,D.C pump will start. 3.5.2 The setting of vacuum tank’s vacuum degree: PSH-202 is a pressure switch. For high purity of hydrogen, gas in seal oil must be reduced to the lowest limit. The lowest limit setting value of the vacuum degree is –88Kpa.g, when vacuum degree exceed the value, it gives out alarm. 3.5.3 Reducer (S-18) When running normally, the pressure of filter inlet pipeline maintain 0.65~0.7Mpa. S-18 should be set according the value. 3.5.4 the setting of vacuum tank liquid level annunciator’s position The middle position of the liquid level annunciator is set as the normal oil level

position. Being up or down 100mm from the normal oil level position, it will give out a signal. 3.5.5 The setting of low limit value of differential pressure regulating valve The oil-gas differential pressure standard value is 0.056Mpa, which decrease to 0.036Mpa as the low limit alarm signal. 3.6

Daily monitor item

3.6.1 the value of oil-gas differential pressure in generator; 3.6.2 the oil level in vacuum tank and float trap; 3.6.3 whether there is oil in liquid level annunciator(LS-201 ); 3.6.4 seal oil vacuum pump run condition 3.6.5 all instrumental display value 3.6.6

seal oil pump outlet pressure

section4 Stator winding cooling water system(see stator winding cooling water control system diagram) 4.1 Main technical parameters: 4.1.1 Stator winding cooling Water: Water pressure at the inlet:

0.1~0.2MPa

Water temperature at the inlet: 45±3℃ Return water temperature: ≤85℃ Total water flow: 45t/h Water quality requirements: Conductivity: 0.5~1.5μs/cm(20℃) PH value: 7-8 Hardness:

2 microgram equivalent litter

4.1.2 Whole volume of

the

system

4.1.3 Circulating water flow required:

3cu.m ~160t/h

Circulating water pressure required:

0.35MPa

4.2 Operating principle of cooling water system Stator winding cooling water system is an independent closed circulating circuit. Water from the tank is pumped and is introduced to exchanger to cool after rising pressure, solid impurity is removed through filter and cooling water flows into the stator winding of the generator. The return water flows back to

the tank by way of circulation. Some auxiliary devices are installed in the system, such as demineralizer, heat exchanger, some gauges are supplied to monitor water temperature, water pressure, conductivity and flow. By-pass pipeline and valve is installed on the stator winding inlet and outlet of the generator so as to wash stator winding in an opposite direction. 4.3 Main equipment of stator cooling water control system, all of the following equipment are assembled on a base plate : 4.3.1 Water tank, it is made from stainless steel. The tank volume is about 1.78 cubic meters. Max. filling water volume of the tank is about 1.6 cubic meters (from horizontal plane to overflow pipe), filling water device and liquid level annunciation is installed on the tank. When water level falls, the contacts

in

the annunciation turn on. Solenoid valve is opened by electric control circuit and cooling water flows into the tank. When water level is high, cooling water should be drained through overflow pipe. 4.3.2 Water pump. Two same type water pumps are furnished in the system, one operating, other for standby. When pressure of pump outlet is less than setting value, the contacts of the pressure control circuit turn on, standby pump is started by electric control circuit. 4.3.3 Water exchanger. The shell of exchanger is made from stainless steel. two heat exchangers are supplied in the system, one for operation, the other for standby. 4.3.4 Water filter. The shell of filter is made from stainless steel. Strainer is made from stainless steel screen. Two filters are installed in the system, one for operating and the other for standby. 4.3.5 Demineralizer. After the system is operated for period of time, cooling water quality will fall gradually, special demineralizer is supplied to improve water quality, it is not allowed to improve hard water directly. Mixed bed type demineralizer is adopted in the system. The cation and anion resin in demineralizer is the ratio of two to one, cooling water flow through the demineralizer is about 5t/h, and is 8% of total flow in the system. Regeneration of resin should be made by the outside of the demineralizer. According to

source of goods, resin type is determined by user. General, filling is about 160 litre. 4.3.6 Conductivity meter. Two same type conductivity meters are supplied the system, one is used to monitor conductivity of cooling water of the generator stator winding inlet. Other to monitor counter conductivity of cooling water of demineralizer outlet so as to determine if resin is need regenerated. 4.3.7 Temperature regulating valve. It is installed on the inlet circulation water pipe of water cooler, it controls circulating water flow so as to control outlet temperature of cooler. 4.4 Points of attention for installation. 4.4.1 Inner wall of pipe must be cleaned. 4.4.2 pipes and equipment of these units must be washed. It must be flanged connected with water supplying control station without impurity. 4.4.3 After system is connected with generator, It should be rinsed

reversely

first, Then has the reverse and forward rinsed alternatively. Water feeding pressures is no more than 0.25MPa. 4.4.4 Circulation water side of water cooler should have water pressure testing of 0.8MPa，30min. In testing, butterfly valve at inlet and outlet of temperature regulator should be closed. 4.4.5 Water pump's overhaul and maintenance can refer to manual provided manufacturer. 4.4.6 All instruments and gauges should be tested regulating in installation. 4.5 Regulating and setting. 4.5.1 Setting of protection value for cutting water. Flow protection return circuit. Stator winding water flow decrease to minimum value, and it cannot rise again in 30 seconds, the protection equipment of generator will be operated. Generator should unload and throw off load, normally the minimum setting value is 37~35t/h. 4.5.2 Regulation and testing of temperature regulator under the load condition according to manual, making feeding water temperature remain at 45±3℃. 4.6 Operation and maintenance of stator winding cooling water system.

4.6.1 According manual provide by manufacture under rated hydrogen pressure. hydrogen pressure in generator should be about 0.1~0.2MPa higher than feeding water pressure of stator winding cool water. When feeding water's pressure is 0.2MPa but flow is stilling sufficient, feeding water's pressure can be raised to 0.23MPa in order to increase flow, but when hydrogen pressure decreased to 0.26MPa. Hydrogen must be compensated. In a word, Hydrogen pressure in generator must be higher than 0.03MPa, darning water's temperature is not higher than 80℃. 4.6.2 When system is feed with water, pump cannot be started to open until overflow pipe start to over flow water pressure should be raised to presetting valve gradually. In this period, if water lever is too lower, operator should compensate water manually. In the meantime, you should open W-52、W-64 valve to drain gas till water flow, then close these valves. 4.6.3 When starting this unit in cold state, operator should heat cooling

water

to make its temperature higher 5℃ than hydrogen temperature by using electric heating equipment. Before operation you must first open W-50、W-51 valve, close W-57、W-56、W-58 valve, turn on electric heating so as to heater and water control station forming circuit. Operator should monitor gauge when water will be heating over H2 temperature 5℃ then cut off the heater power. Heater may installation near W-52、W-51 valve, so as to operation. 4.6.4 Sample gas from sampling valve on top of water tank is found its hydrogen higher than standard content after analyzing gas, operator should stop generator and check, putting stress on checking coil introduction water pipe. Normal operation sample valve should be closed. 4.6.5 When water cooler is supplying water circulately. Gas should be drained from water cooler's top. 4.6.6 Water feeding pressure of demineralizer should be limited under 0.35MPa. When water draining conductivity is higher than 0.5 μ s resin regeneration should be considered. 4.6.7 All of instrument and meters should be calibrated regularity.

Chapter6

DESCRIPTION OF CIRCULATING WATER SYSTEM Section1

1.1

General situation

2×300MW coal fired power plant is located in the north of Cilacap, Central

Java, Indonesia and adjacent on the INDIAN OCEAN. 1.2 meteorological condition 1.2.1 Atmospheric pressure（mbar） Average barometric pressure： 1.2.2

1008.2

Temperature（℃） Maximum monthly average ambient temperature：32.7 Minimum monthly average ambient temperature：20.9

1.2.3

Maximum extremely temperature：

34.5

Minimum extremely temperature：

17.4

Air relative humidity（％） Maximum monthly relative humidity：

93

Minimum monthly relative humidity： 1.2.4

Rainfall（mm） Maximum recorded rainfall for 12 hrs： Maximum recorded rainfall for 24 hrs：

73 77 230

Design rainfall intensity：70mm per hour for a 60-minute storm on a 15-year frequency 1.2.5

Wind speed Maximum design wind speed at 10m：120km/h Direction of prevailing wind：from SE to NW for 80% of year

1.2.6 1.3

Earthquake intensity：

0.3g

Ocean hydrologic data

1.3.1 Tide level 99% tidal water level 97% tidal water level 10% tidal water level 1% tidal water level

0.37m 0.48m 1.99m 2.46m

0.1% tidal water level

2.67m

100 years return period highest tidal water level 33 years return period lowest tidal water level

2.973m -0.077m

Wave： Deep-water wave for Cilacap Sea (50 years return period) Extreme value

Cumulative frequency

Wave height (m)

Wave period (s)

H13%=Hs

4.86

10.58

H1%=1.51Hs

7.37

13.7

H4%=1.28Hs

6.20

12.03

H5%=1.22Hs

5.93

11.75

1.3.3Water temperature design average seawater temperature: 26℃ design maximum seawater temperature: 34℃ 4) suspend sediment Year-to-year highest suspend sediment content：No information Year-to-year average suspend sediment content：No information

Section2

Design description of circulating water system

The once through cooling water system is adopted in this project and 2 sets circulating water pumps are installed for each 300MW unit. One circulating water pump house is common for 2 units. Two main circulating water pipes for two units are not connected with each other. 2.1

Main parameters of circulating water system

¾ Cooling surface of condenser：

17750 m2

¾ Cooling water pipe of condenser：

Ti, ф25×0.5

¾ C.W. Flow：

41050 m3/h

¾ C.W. inlet temp.：

26 ℃

¾ C.W. outlet temp.：

34℃

¾ Back pressure：

0.0067MPa

¾ Water velocity：

2.3m/s

¾ When C.W. inlet temp. is 34 ℃, Back pressure is 0.0118MPa ¾ Hydraulic loss and calculation of C.W. system at 100% flow 1) From water Intake to inlet chamber：

1.508 m

2) From C.W. pump to condenser inlet：

3.492 m

3) Condenser：

6.0 m

4) From condenser outlet to siphon well inlet：

3.754 m

5) Total head loss：

14.754 m

6) Static head from siphon well to mean water level: 7) Total head required:

2.879m 17.633 m

¾ circulating water flow for 2 units circulating water flow list (2X300MW) Table 2-1 circulating water flow NO. 1 2

Item of water demand Cooling water for condeser Cooling water for auxiliary heat exchanger Total

1×300MW 2×300MW 41050

82100

3300

6600

44350

88700

Remark

¾ Circulating water pump is vertical style mixed-flow type, model number is 72LKXA－17.9,the rated capacity is 6.26m3/s, total head is 0.179Mpa.The power of the match motor for circulating water pump is 1600KW and voltage is 6000V. 2.2

The structures and buildings of circulating water system The once through cooling water system is adopted in this project. The seawater

flow by gravity from water intake dock basin to C.W. pump inlet chamber through the C.W. intake open channel and be pumped to condenser and auxiliary heat exchanger through C.W. inlet FRP pipe by C.W. pump. After heat exchanged in condenser and auxiliary heat exchanger, the outlet hot seawater flow to siphon well through C.W. outlet FRP pipe and under drain, at last the hot seawater flow by gravity from siphon

well to sea through C.W. outlet open channel. 2.2.1

Structure of water intake

1) Water intake adopt bank side dock basin type according to the result of the 《WATER INTAKE REPORT》and water intake structure consist of breakwater, dock basin, intake open channel and bar screen. 2) Bar screen is installed at the end of intake open channel, the distance between the bars is 200mm.Water velocity across the bars is about 0.2m/s at design flow. 3) The detail design and arrangement of structure of water intake reference to the drawings and description provided by PT.Zhenhua Indonesia. 2.2.2 Water inlet chamber 1) Water inlet chamber is outdoor rectangular type and union with C.W. pump house. The dimension of inlet chamber is 24m×21m×12.3m. 2) The top platform elevation is +3.7m. 3) The water inlet chamber is divided into four independent parts for 4 sets circulating water pump, in each part, 1 set cleaning trash device, 1 set travelling band screen are installed. Distance between bars of cleaning trash device is 50mm and the mesh size of traveling band screen is 6mmX6mm. 4) For the purpose to cut off the water flow when cleaning trash device, travelling band screen and C.W. pump maintenance, 2 sets steel gate are installed upstream of cleaning trash device common for four independent parts of inlet chamber. 1set guiding groove for steel gate is installed in each part of inlet chamber. The start and stop of the steel gate is static water type. 5) There is 1 set cleaning trash device in each part of inlet chamber, and 1 set mobile trash rake is installed common for 4 sets cleaning trash devices. 6) 4 sets wash pumps, pipeworks and nozzles are provided for 4 sets travelling band screen back washing. the back washing pump specification is as following: EHG125-80-200 type ，Q=150m3/h H=0.46MPa N=37KW. 7) Two cooling water pumps for C.W.pump mating motor are installed at the platform of inlet chamber. The pump is deep well pump and its specification is as following: 12RJLC/4 type, Q=125~160~200m3/h H=0.39~0.345~0.285MPa N=30KW 2.2.3 Circulating water pump house

2sets C.W. pumps are installed for each 300MW unit in this project and one C.W. pump house is common for 2 units. The C.W. pump house is located at opposite side of the road which west of the turbine house. 4 sets 72LKXA-17.9 type C.W. Pump (Q=6.26m3/s, H=0.179MPa、n=425r/min, mating motor is YKSL1600-14/1730-1 type, N=1600kW, V=6000V,IP54) and 2 sets HFY65-12.5 type drainage sump pump (Q=25m3/h, H=0.125Mpa,N=3kW) are installed in C.W. pump house. The start and stop of C.W. pump can control at central control building and on site. Hydraulic

control

butterfly

valve

(D741aX-6

type,

DN1800,

PN=0.60Mpa,N=4kW,V=380V) is installed at the outlet of C.W. pump and can be closed automatically with quickly and slowly two closing stages. The closing time can be determined by the shakedown test. One electric double beam bridge crane (with cabinet) installed in C.W. pump house for equipment maintenance. The operation platform of the C.W. pump house has the control device room and maintenance area. The operation platform elevation is +3.70m. 2.2.4 Circulating water pipe The main circulating water inlet and outlet pipes nominal diameter is DN2200 and pipes are all fiberglass reinforced plastic pipe (FRP). The flow through circulating water pipe is 12.51m3/s and flow velocity is about 3.294m/s. For the purpose to enter into the pipe inside when pipe installation and maintenance, 2 manholes will be arranged at each main DN2200 pipe (near the C.W. pump house and turbine house). 2.2.5 Circulating water outlet under drain The circulating water flow out of the condenser and auxiliary heat exchanger of 2 units through the under drain enter into siphon well. The dimension of the R.C. under drain is 2X2000mmX2500mm .the flow is 25.03m3/s and flow velocity is about 2.503m/s. 2.2.6 Siphon well Siphon well is reinforced concrete construction and located at southwest of the power plant. The dimension of siphon well is 12400mmX20000mmX8500mm.The top platform elevation is +7.00m and the elevation of the top of weir in the siphon well is +3.00m. 2.2.7 Circulating water outlet open channel The circulating water flows out of the siphon well through the open channel enter into the sea by gravity. The bottom width of the open channel is 4500mm and

bottom slope is 0.002.The flow is 25.03m3/s and flow velocity is about 3.01m/s. 2.2.8 Cooling water for auxiliary heat exchanger There is 3300m3/h circulating cooling water flow from main circulating water pipe to auxiliary heat exchanger for each unit. The inlet and outlet Cooling water pipes for auxiliary heat exchanger nominal diameter is DN700 and are all FRP pipes. The water discharge from the auxiliary heat exchanger enter into circulating water outlet pipe and then flow to siphon well and enter into the sea through circulating water outlet open channel at last.

Section3

The construction and installation description of the circulating water system

3.1 The construction and installation dimensions in this project shall be according to the data which written on the drawings and forbid using the data which is measured in scale on the drawings. 3.2 The construction and installation shall be according to the requirements of the drawings. Drawings and relative descriptions shall be understood before construction and installation. If the drawing’s content isn’t clear or has other questions, please consult with site designer in time. 3.3 Embedded parts, embedded pipes and reserved holes in drawings shall be constructed simultaneously with the construction of the structure. After checking up the dimensions of arrival equipment and finding without mistake, the embedded parts will be constructed. Allowable dimensions deviation of embedded parts shall be not exceeded ±10mm except for that noted specially in drawings. Installation organization shall examine and cooperate at all hours in the process of structure construction. 3.4 The installation management plan shall be done ,the construction order of underground pipes shall be prepared at fist time, the lower pipes or foundations will be constructed at first and upper pipes later. 3.5 For the requirement of installation for circulating water pipe, please see the specification, which provided sub supplier by LIANYUNGANG LIANZHONG FRP CO.LTD. 3.6 The heavy-duty equipments shall be transported through the reinforce area of circulating water pipe after circulating water pipe backfilling, and the temporary pillow shall be beded on the pipe reinforce area to protect the circulating water pipe from crushing. 3.7 The shakedown test, installation and maintenance of all equipments in the circulating water system shall be performed according to the requirements of manufacturers. 3.8 Expansion joints for C.W. pump and hydraulic control butterfly valve are only use for adjusting the clearance between pipes when valve or pump installation and disassembly. After valve or pump installed, it must lock the lock bolt in joint to make the pipe and joint as a rigid body.

section4

Operating management description of circulating water system

4.1 C.W. pump 4.1.1 There are 4 sets C.W. pumps for 2 units in the C.W. pump house. And 2 sets C.W. pumps provide cooling water for one 300MW unit jointly at normal operation. When only one set C.W. pump provides cooling water for one unit at certain case, the other C.W. pump for the same unit is standby and interlock with the operation pump. And when the operation pump stop by accident, the interlocked pump shall start up automatically. 4.1.2 The C.W. pump and its outlet hydraulic control butterfly valve can be started up or stopped at central control room or at site by manual control. The operation position of C.W. pumps and hydraulic control butterfly valves can be displayed at C.W. pump house control device room and central control room. 4.1.3 The C.W. pump interlock with its outlet hydraulic control butterfly valve and cooling water pump for C.W. pump mating motor. The interlocked operation program is as following (for example with C.W. pump which code is 10PAC11APOO1,reference to drawing “circulating water pump house system flow diagram” and drawing NO. is 50-F209S-S0203A-01): 4.1.3.1 Normal operation The C.W. pump can be started up or stopped independently by manual control and started up or stopped interlocked with outlet valve at central control room. In addition, the C.W. pump and its outlet valve can be started up or stopped at site by manual control. （1）startup program of C.W. pump at normal operation: After push the interlocked startup button of C.W. pump, the program automatically confirm the C.W. pump outlet hydraulic control butterfly valve (10PAB11AA001) is closed and simultaneously judge the cooling water pump (00PAD11AP001 or 00PAD12AP002) for C.W. pump mating motor if startup. If the cooling water pump is already startup then open the motorized valve (10PAD11AA001), otherwise the program will start up the cooling water pump and open the motorized valve. If above process complete, program will open the C.W. pump outlet valve after 60 second (adjustable, 5 min for the fist time to operate), when the open angle reach 15 degree the program will start up the C.W. pump. Above process is interlocked at normal operation. （2）stop program of C.W. pump at normal operation: After push the interlocked stop button of C.W. pump, program will close the C.W. pump outlet valve and stop the C.W. pump motor after the valve closed angle reach 20 degree. 60 second (adjustable) later, the program will close the motorized valve of cooling water pipe for C.W. pump mating motor (only when 4 sets C.W. pump stop together, the cooling water pump shall be stopped interlocked). The outlet valve can be closed automatically

with quickly and slowly two closing stages: the fist is quickly closing stage, closing time is about 2.5~20 second (adjustable) and closing angle is about 70°±8°(adjustable); the second is slowly closing stage, closing time is about 6~60 second (adjustable) and closing angle is about 20°±8°(adjustable); Above process is interlocked at normal operation. （3）It shall be according to the order demanded at above description when above devices independently operate . Adjusting the order is not allowed. 4.1.3.2 The processing when accident (for example with C.W. pump which code is 10PAC11APOO1) （1）If operating personnel receive the alarm signal (such as motor bearing lube oil temperature, electric current value, flow alarm switch signal of cooling water inlet pipe for C.W. pump mating motor and so on) of C.W. pump and mating motor(10PAC11APOO1) or hydraulic control butterfly valve(10PAB11AA001),he shall make sure quickly what happened and stop the C.W. pump by manual control after confirmed by the administration of power plant. It’s stop program is as same as stop program at normal operation. （2）When C.W. pump (10PAC11APOO1)is stop by accident, it will send the alarm signal to central control room and interlocked close the outlet hydraulic control butterfly valve(10PAB11AA001) simultaneously. The outlet valve will close automatically with quickly and slowly two closing stages according to the adjusted closing angle and time. 60 second (adjustable) later after C.W. pump is stopped, it will interlocked close the motorized valve (10PAD11AA001) of cooling water pipe for C.W. pump mating motor. （3）When hydraulic control butterfly valve(10PAB11AA001) automatically close by accident, the alarm signal will be sent to central control room and interlocked close the C.W. pump (10PAC11APOO1)，60 second (adjustable) later after C.W. pump is stopped , it will interlocked close the motorized valve (10PAD11AA001) of cooling water pipe for C.W. pump mating motor. （4）If hydraulic control butterfly valve(10PAB11AA001) can not open completely by accident after C.W. pump start up 45 second, the alarm signal will be sent to central

control

room

and

interlocked

close

the

C.W.

pump

(10PAC11APOO1)，60 second (adjustable) later after C.W. pump is stopped , it will interlocked close the motorized valve (10PAD11AA001) of cooling water pipe for C.W. pump mating motor.

4.1.3.3 For the purpose to reduce the pump stop water hammer pressure, the hydraulic control butterfly valve (10PAB11AA001) closing time of two closing stages shall be determined by the shakedown test. The requirement of the shakedown test shall be reference to the relative specification, which provided by manufacturers of C.W. pump and hydraulic control butterfly valve. 4.1.3.4 When the circulating water pipe is empty or the prime operation, the suggestion opening extent of hydraulic control butterfly valve is about 1/3 of the totally opening and it shall fill the water into the circulating water pipe slowly. After confirmed that all pipes fully fill with the water, it can completely open the valve. 4.1.3.5 There are pressure meters at the outlet of all C.W. pumps, the design operation pressure is about 0.179MPa. 4.2 Cleaning trash device (with mobile trash rake) The control of the cleaning trash device (with mobile trash rake) is according to the water level difference between upstream and downstream of cleaning trash device. For example with cleaning trash device which code is 10PAA21ATOO1,the operation program of cleaning trash device is as following: (1) Program will inspect the water levels of upstream and downstream of cleaning trash device, when the water level difference reach to 0.3m(adjustable), the mobile trash rake will automatically start up, until the water head reduce to 0.1m(adjustable) it will stop automatically. The operation time shall be not less than 30min at each time. (2) Mobile trash rake will start up automatically at intervals of 24 hours (adjustable) for the purpose to prevent the revolving parts from being got stuck. In this process the mobile trash rake shall clean cleaning trash device one by one of each inlet chamber.

The operation time shall be not less

than 30min at each time. (3) Cleaning trash device (with mobile trash rake) can be started up and stopped by manual control at site.

4.2 Travelling band screen The control of the travelling band screen is according to the water level difference between upstream and downstream of travelling band screen. For example with travelling band screen which code is 10PAA31ATOO1,the operation program of travelling band screen is as following:

（1） Program will inspect the water levels of upstream and downstream of

travelling band screen, when the water level difference reach to 0.3m(adjustable), the travelling band screen will start up automatically, until the water head reduce to 0.1m(adjustable) it will stop automatically. The operation time shall be not less than 30min at each time.

（2） Travelling band screen will automatically start up at intervals of 24 hours (adjustable) for the purpose to prevent the revolving parts from being got stuck. The operation time shall be not less than 30min at each time. （3）avelling band screen can be started up and stopped by manual control at site.

4.3 Travelling band screen back wash pump The start up and stop of the travelling band screen back wash pump shall be interlocked with the travelling band screen. When travelling band screen start up, the program will start up the back wash pump too; when travelling band screen stop, the program will stop the back wash pump too. There are 4 sets back wash pump for 4 sets travelling band screen. One back wash pump is working for one travelling band screen. When the operation back wash pump is accident, the program will send the alarm signal to control room and display the code of the accident pump.

4.4 Y type filter on the outlet of travelling band screen back wash pump The differential pressure switch is installed between the inlet and outlet of the Y type filter. When the pressure differential reach to 0.05MPa(adjustable), the switch will send the alarm signal to C.W. pump house control device room and central control room to remind the operating personnel to wash the filter at site. The differential pressure can be displayed at control device room.

4.5 Cooling water pump for C.W. pump mating motor 4.6.1 there are 2 sets cooling water pumps for C.W. pump mating motor and interlocked with each other. When the operation pump is stop by accident, the interlocked pump shall start up automatically and at the same time the program will send the alarm signal to control room and display the code of the accident pump. 4.6.2 1 set cooling water pump provides cooling water for 4 sets C.W. pump mating

motors (the other stand by). The start up and stop of the cooling water pump is interlocked with the C.W. pump (see section 4.1). 4.6.3 Cooling water pump can be started up and stopped by manual control at site or at central control room. The operation position of cooling water pump can be displayed at C.W. pump house control device room and central control room. 4.7 Drainage sump pump 2 sets drainage sump pumps are installed at drainage sump in the valve pit of C.W. pump house. There are 2 sets drainage sump pumps interlocked with each other. 2 sets pumps are controlled by the water level of drainage sump. When the water level is 1.30m, a drainage sump pump will start up automatically and until the water level reduce to 0.70m the pump will stop automatically. When a drainage sump pump is already operating but the water level still rise to 1.80m，then the other stand by pump will start up automatically and at the same time it will send alarm signal to control room. When the operating personnel receive this signal he shall inspect and treat the problem immediately at site. When the operating pump is accident, the stand by pump will start up automatically and at the same time it will send alarm signal to control room. The operating personnel shall repair the accident pump soon. The water level signal of drainage sump and operating position signal can be displayed at site. 4.8 The water level of inlet chamber The water level of inlet chamber at downstream of travelling band screen shall be continuously displayed at site and central control room. When the water level under 7.0m(from the chamber bottom), an alarm signal will be sent to central control room for the purpose to remind the operating personnel that the water level is under the design lowest water level. The operating personnel shall take appropriate action after receive this low water level alarm signal. 4.9 The maintenance and checking of devices in circulating water system There is maintenance area in C.W. pump house. The maintenance of C.W. pump shall be performed in maintenance area. The hand oil pump is used for changing the lubricating oil of C.W. pump mating motor. The hand oil pump can be put in the maintenance area. The steel gate shall be needed to cut off the flow when the inlet chamber maintenance. The cut-off and start-up of steel gate is adopted static water type. When cutting off the flow of the inlet chamber, it shall stop all the pumps which suck water

in this inlet chamber first and then put steel gate in the chamber to cut off the flow, at last empty all water of inlet chamber by mobile discharge pump. After the chamber maintenance complete, pump water fill with this chamber from near by chamber by using mobile pump and still the water level upstream steel gate is as same as downstream steel gate, the steel gate can be lifted. The steel gate shall put in the maintenance area of inlet chamber（the robber water seal belt of steel gate shall be not pressed when putting）and mobile discharge pump can be put in the maintenance area of C.W. pump house. The mobile discharge pump shall be used to remove sand in the inlet chamber too. The devices of inlet chamber shall be lift to the maintenance area near by the inlet chamber by truck crane

to check.

Before and after plant operating, it shall clean up the settling sand in intake dock basin and intake open channel by dredger to prevent the large quantity sand from entering into circulating water system; it shall clean up the marine life that adhere to the surface of devices and inside surface of circulating water pipes in the period of the unit maintenance 4.10 Notices （1） Operating personnel shall pay attention to the water level of inlet chamber. It shall guarantee the submersed water depth of C.W. pump to prevent the air from entering into inlet of C.W. pump. （2） To avoid air accumulation at the top of cooling water pipes of condenser (or at top of condenser water chamber), it shall open the vent cock and vent valve before the condenser operating, and then fill the cooling water pipes and water chamber with water slowly. After doing this it can close the vent cock and vent valve. （3） It shall start up or stop C.W. pumps one by one with intervals more than 10min. （4）

The appropriate closing stroke and closing time of C.W. pump outlet hydraulic

control butterfly valve are very important to reduce the pressure of water hammer and avoid the C.W. pump rotating inverted. The closing time and closing stroke shall be determined by shakedown test before the circulating water system operating.