Part 1 Operation Manual of Steam Turbine

India 2×600MW Mahan Coal Fired Thermal Power Plant Operation and Maintenance Manual Volume I: Operation Manual Part 1: Operation Manual of Steam Turbine

Harbin Power Engineering Company Limited Harbin Huitong Electric Power Engineering Co.,Ltd April, 10th, 2011 P

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Content 1 Technical specifications and characteristics of main and auxiliary equipments of turbine-generator unit .................................................................................................................... 3 1.1 1.2 1.3 1.4 1.5 1.6 2 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 3 3.1 3.2 3.3 3.4 3.5 3.6 4 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 4.9 4.10 4.11 4.12 4.13 4.14 4.15 4.16 4.17 4.18 4.19 4.20 4.21 4.22 4.23 4.24 4.25 4.26

Technical specifications of turbine proper ....................................................................... 3 Turbine characteristic ......................................................................................................... 5 Boiler and generator specification .................................................................................... 5 Auxiliary specification ........................................................................................................ 7 Regulation and protecting system .................................................................................. 26 Turbine unit protection ..................................................................................................... 30 Turbine unit start ................................................................................................................... 31 Unit start general rules ..................................................................................................... 31 Preparation before unit start ............................................................................................ 32 Test before start ................................................................................................................. 33 Turbine unit cold state start ............................................................................................. 34 Unit warm, hot, very hot start........................................................................................... 43 DEH operation mode explanation.................................................................................... 44 Unit stop ............................................................................................................................. 45 Maintaining after turbine stops ........................................................................................ 49 Unit operation and maintenance ......................................................................................... 49 Operation and maintenance ............................................................................................. 49 Motor normal operation and maintaining ....................................................................... 50 Unit operation mode ......................................................................................................... 52 Parameter supervision in normal operation................................................................... 53 Periodic work ..................................................................................................................... 60 Unit interlock protection and test .................................................................................... 62 Unit trouble shooting ............................................................................................................ 76 Principles of trouble shooting ......................................................................................... 76 Conditions and treatment of emergency stop and treatment ...................................... 77 Steam parameters are abnormal...................................................................................... 80 Unit load vibration ............................................................................................................. 81 Unit load rejection ............................................................................................................. 81 Condenser vacuum drop .................................................................................................. 82 Unit high vibration ............................................................................................................. 83 Turbine water impact......................................................................................................... 84 Turbine blades break......................................................................................................... 85 Turbine abnormal axial displacement ............................................................................. 85 Turbine lubricate oil system fault .................................................................................... 86 Turbine bearing temperature high ................................................................................... 88 EH oil system fault ............................................................................................................ 89 Sealing oil pressure low ................................................................................................... 90 Closed circulating water system fault............................................................................. 90 Auxiliary equipment fault ................................................................................................. 91 Motor fault .......................................................................................................................... 92 Auxiliary power lost .......................................................................................................... 94 Hydrogen system fault ...................................................................................................... 95 Stator cooling water interrupt .......................................................................................... 96 Fire ...................................................................................................................................... 96 DCS fault............................................................................................................................. 97 Measures avoiding water entering into turbine and bearing bend .............................. 98 Measures avoiding turbine oil leakage ......................................................................... 100 Main steam valve or governor valve blocks after turbine trips .................................. 100 Measures avoiding turbine over speed ........................................................................ 101 1

5 Start curve ............................................................................................................................. 102 5.1 Cold state curve ............................................................................................................... 102 5.2 Warm state start curve .................................................................................................... 103 5.3 Hot state start curve ........................................................................................................ 105 5.4 Extremely hot state curve ............................................................................................... 106 5.5 Recommended values of keeping turbine running speed .......................................... 107 5.6 Cold state rotor heating curve ....................................................................................... 108 5.7 Hot state start recommended value .............................................................................. 109 5.8 Main steam parameters during start ..............................................................................110 5.9 Changing load recommeded value——fixed pressure mode...................................... 111 5.10 Recommeded value of changing load............................................................................ 111 5.11 Circulating indexes under different load increase rate and decrease rate ................112 5.12 Gland sealing steam temperature recommended valves ............................................113 5.13 Typical HP cylinder cooling curve ..................................................................................114 6 6.1 6.2 6.3 6.4 6.5 6.6 6.7 6.8 6.9 6.10 6.11 6.12 6.13 6.14 6.15 6.16 6.17 6.18

Auxiliary operation regulations ..........................................................................................115 General ..............................................................................................................................115 Start & stop of circulating water system .......................................................................117 Open cooling water system start and stop....................................................................118 Closed circulating cooling water system start and stop .............................................119 Start & stop of auxiliary steam system ......................................................................... 121 Condensing water system start and stop ..................................................................... 122 Deaerator start and stop ................................................................................................. 124 Motorized feeding water pump start and stop ............................................................. 127 Steam driven feed water pump group start & stop ...................................................... 129 Heaters start and stop..................................................................................................... 134 Turbine gland sealing start and stop ............................................................................ 137 Vacuum system stop....................................................................................................... 138 Turbine lubricate oil system start and stop .................................................................. 140 Turbine oil cooler start and stop.................................................................................... 142 EH oil system start and stop .......................................................................................... 143 Generator sealing oil system start and stop ................................................................ 145 Generator hydrogen cooling system start and stop ................................................... 148 Start and stop of generator stator cooling water system ........................................... 152

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1 Technical specifications and characteristics of main and auxiliary equipments of turbine-generator unit 1.1 Technical specifications of turbine proper 1.1.1 Turbine specifications: Name

Specification

Unit Model

N600-16.7/538/538

Type

Sub-critical, once-middle reheat, single-shaft, three cylinder and four stages steam extraction, double back pressure condenser type turbine

Rated power

600 MW（TMCR working condition)

Maximum power

648.6 MW（VWO working condition）

Rated running speed

3000 r/min

Running direction

(from turbine to generator) clockwise

Working frequency

50 Hz

Steam exhaust pressure

10.13Kpa Total 40 stages

Flow stages

HP cylinder: one (1) single-row governing stage ＋ nine (9) pressure stages IP cylinder: six (6) pressure stages LP cylinder: 2×2×6 pressure stages (two double flow low pressure cylinders)

Turbine outline dimension

27.8×11.4×7.24 m

（L×W×H） Final stage blade highness

680 mm

Elevation from center line to operation layer

1070 mm

Steam distribution mode

Nozzle governing

Starting mode

HP-IP combined start-up mode

Feed water heat returning stage number

Three HP heaters＋one deaerator＋four LP heaters

Feed water temperature

276℃

Critical rotating speed of shaft

Rotor

Ⅰ stage

Ⅱ stage

HP &IP rotor

1704

4181

3

Heat rate Main steam pressure Reheat steam pressure Exhausting pressure of HP cylinder Main steam temperature Reheat steam temperature Main steam flow Reheat steam flow Average back-pressure Exhausting flow of LP cylinder Make-up water rate Final feed water temperature

1648

3859

LP rotor B

1610

3584

Generator rotor

780

2073

Turning gear running speed

3.35 r/min

Noise level

≤90 dB(A)

Manufacturer

Harbin Turbine Co., Ltd.

1.1.2

Unit output

LP rotor A

Main parameters of turbine designed working condition

Unit

TMCR condition

TMCR condition + 3% make up water 600

TMCR condition (maximum back -pressure) 600

VWO condition

VWO condition +3% make up water 644.4229

All HP heater cut off conditi on 600

75% TMCR (Sliding pressure)

60% TMCR (Sliding pressure)

40% TMCR (Sliding pressure)

MW kJ/kW .h MPa (a) MPa (a)

600

450.004

360

240.145

8149.5

8204.1

8269.1

8127.7

8182.7

8409.5

8275.7

8500.3

9089.5

16.7

16.7

16.7

16.7

16.7

16.7

13.64

11.07

7.64

3.438

3.442

3.473

3.752

3.728

3.567

2.556

2.076

1.459

MPa (a)

3.820

3.824

3.859

4.169

4.142

3.963

2.84

2.307

1.621

℃

538

538

538

538

538

538

538

538

524.9

℃

538

538

538

538

538

538

538

531.6

498.1

t/h

1875.12

1890.20

1908.71

2060

2060

1631.7

1359.21

1091.37

769

t/h

1579.60

1583.12

1597.75

1725.78

1716.49

1606.8

1168.13

949.10

678

KPa

10.13

10.13

11.87

10.13

10.13

10.13

10.13

10.13

10.13

t/h

1128.58

1116.52

1131.1

1228.07

1207.16

1210.3

866.36

722.53

521.32

%

0

3

3

0

3

0

0

0

0

℃

275.6

275.8

276.5

281.7

281.4

181.1

256.7

244.5

225.4

1.1.3

648.614

All stages extraction parameters when turbine in TMCR working condition Extraction Series

1st extraction (to no.1 HP heater) 2nd extraction (to no.2 HP heater) 3rd extraction (to no.3 HP heater) 4th extraction (to deaerator) 4th extraction (to BFP turbine) 4th extraction (to aux. steam header) 5th extraction (to no.5 LP heater) 6th extraction (to no.6 LP heater) 7th extraction (to no.7 LP heater) 8th extraction (to no.8 LP heater)

Flow kg/h 128990 122580 79790 86580 92960 ≤65000 46950 46130 56240 58400 4

Pressure MPa(a) 6.00 3.804 1.84 0.878 0.873 0.873 0.336 0.189 0.099 0.0391

Temperature ℃ 386.7 325.0 444.7 339.5 339.4 339.4 226.8 166.6 105.1 75.4

1.2 Turbine characteristic 1.2.1

This turbine is sub-critical, once-middle reheat, single-shaft, three cylinders and four stages steam extraction, condenser type turbine; it adopts reversal type impeller blade, whole forged rotor, multi-layer cylinder and digital electric hydraulic regulation. Its structure is compact and economic with high operation efficiency and safe reliability. This turbine is used for offer basic load for middle sized power grid and is also suitable for load regulation and supplying basic load for large scale power grid. Life of this unit is more than thirty (30) years. This kind of unit is fit to drought area, use air cooling system. Operation hours per year of this unit is more than 8000 hours.

1.2.2

#7 bearing in bearing system of turbine generator unit adopt Jingshiboli bearing, #1～6 bearing are four tile tilting-pad bearing. Bearing vibration measuring devices are installed on X and Y up tile of bearings and measuring devices are installed on down bearing. Thrust bearing is in bearing box and it is a equally loaded bearing with automatic and even load distribution between tiles, pile is supported on fixing inner balancing block composed of two halves. There‟re 3 absolute anchor point of the unit: first is at #2 bearing box, the other two is at center of #1 and #2 LP cylinder, two horizontal anchor keys and two axial anchor keys pre-buried in foundation limit the moving center of them, which forms absolute anchor point of the unit. HP & IP cylinder are supported by four „cylinder claws‟, which is built on bearing box. „Cylinder claw‟ can slide freely on keys through cooperation between „cylinder claw‟ and bearing box. Flange form steel joint connect rotators, thrust bearing at #1 bearing box which forms relative anchor point of the unit.

1.2.3

Two steam-driven feed water pumps with BMCR capacity of 50% and one motorized speed changing feed water pump with BMCR capacity of 50% for start/standby. Normal working steam source is from fourth stage extraction steam, steam source for low load operation and commission is from auxiliary steam system. Exhaust steam of BFPT is extracted to condenser of the turbine.

1.2.4

Three vertical condenser pumps with capacity of 50% are installed in condensing water system. Extractive treatment of condensing water adopts IP system. Condenser is single flow, double back pressure surface type; it has double shells and arranged horizontally.

1.2.5

Open circulating cooling water system and closed circulating cooling water system are adopted as cooling water system. Open circulating cooling water system is from circulating water, closed circulating cooling water system supply cooling water to auxiliary equipments in main hall.

1.2.6

Control oil system of turbine adopts HV fire resistant oil and is completely separated from lubricate oil system, which improves the speediness of speed regulation system, reliability and agility.

1.2.7

Unit is designed as HP cylinder starting mode. Bypass system adopts HP, LP bypass of two stages in series with capacity of 60% BMCR, which can protect unit operation safely.

1.3 Boiler and generator specification 1.3.1

Boiler designed specification ITEMS

UNIT

BMCR

Steam flow rate of superheater outlet

t/h

2060

1866.68

Steam pressure of superheater outlet

MPa(g)

17.5

Steam temperature of superheater outlet

℃

Steam flow rate of reheater outlet

t/h

541 1725.9

17.34 541

5

TMCR

1572.73

℃

Steam temperature of reheater outlet Steam pressure of reheater outlet

MPa. (g)

541 3.817

541 3.472

℃

335.0

335.0

MPa(g)

4.007

3.646

Temperature of feed water

℃

281.0

275

Flue gas temperature at air preheater outlet (unrevised)

℃

138

137

Flue gas temperature at air preheater outlet (revised)

℃

131

131

Boiler efficiency (based on HHV)

%

Steam temperature of reheater inlet Steam pressure of reheater inlet

1.3.2

87.1

Generator designed specification Item

Unit

Generator type

Data QFSN-660-2YHG

Rated capacity SN B

Rated power PN B

B

B

Rated power factor cosφN B

Stator rated voltage UN

MVA

705.88

MW

600 0.85(lagging)

B

kV

20

A

20377

Empty load excitation voltage

V

144.2

Empty load excitation current

A

1480

Rated excitation voltage UfN

V

465.6

A

4557

Full load frequency η

％

98.85

Rated frequency

Hz

50

Rated running speed

r／min

3000

B

Stator rated current IN B

B

B

B

Rated excitation current IfN B

B

B

phase

3

Stator winding connection mode

YY

Excitation mode

Static self and shunt excitation

6

1.4 Auxiliary specification 1.4.1

Bypass system

1.4.1.1 HP & LP bypass system Technical parameter name

Unit

Cold state start

Warm state start

Hot state start

Extreme hot state start

working condition

Inlet steam pressure

MPa

5.9

5.9

7

8

17.6

7.87

Inlet steam temperature

℃

340

420

450

485

541

520

Inlet steam flow

t/h

102.3

251.3

259.6

288.5

1236

769

Outlet steam pressure

MPa

1.1

1.1

1.1

1.1

4.17

1.5

Outlet steam temperature

℃

~200

~250

~270

~300

335.6

320

Outlet steam flow

t/h

111

283

293

326

1423

885

Pressure

MPa

~12

~12

~15

~15

23.33

~15

Temperature

℃

150

150

150

150

180.2

150

Flow

t/h

18

32

34

38

187

116

Inlet steam pressure

MPa

1.0

1.0

1.0

1.0

3.753

1.4

High pressure steam change-over valve

HP spraying governing valve

7

VWO

Auxiliary power working condition

Unit

Cold state start

Warm state start

Hot state start

Extreme hot state start

working condition

Inlet steam temperature

℃

300

400

435

470

538

501

Inlet steam flow (total flow of LP bypass)

t/h

111

283

293

326

1423

885

Outlet steam pressure

MPa

0.04

0.1

0.11

0.12

0.5884

0.34

Outlet steam temperature

℃

82

99

102

105

160

138

Outlet steam flow

t/h

2x65

2x177

2x188

2x214

2x968

2x592

Pressure

MPa

3.16

3.16

3.16

3.16

3.16

3.16

Temperature

℃

46.5

46.5

46.5

46.5

46.5

46.5

Flow

t/h

2x9

2x35

2x41

2x51

2x257

2x149

Technical parameter name LP change-over valve

LP spraying water governing valve

8

VWO

Auxiliary power working condition

1.4.1.2 Hydraulic actuator Sort Item

HP bypass HP bypass valve

Bypass constitution Type

HBSE280-350

Spraying governing valve 100DSV

LP bypass Spraying isolation valve 840

LP bypass valve NBSE60-700

Spraying governing valve 840H

Model

Angle

Angle

Through

Angle

Through

Drive mode

Hydraulic

Hydraulic

Hydraulic

Hydraulic

Hydraulic

State after losing electricity

Lock-up

Lock-up

Lock-up

Lock-up

Lock-up

17.6

22.81

23.33

3.75

2.42

C

541

180.2

180.2

538

46.5

Mpa

4.17

4.69

22.81

0.5884

1.11

C

335.6

180.2

180.2

160

46.5

Mpa

17.6

22.81

23.33

3.75

2.42

Rated value

t/h

1236

187

187

2x711.5

2x257

Maximum value

t/h

-

-

-

-

-

linear

=%

On/off

linear

=%

mm

199.7

38.1

76.2

402.9

76.2

kN

87

3r/min, make sure that turning gear on CRT really exit from running and turning gear motor stops. 3） When running speed reaches to 200r/min, check and make sure that turning gear oil spraying solenoid valves are closed automatically. 4） When the turbine rotate speed reach 600r/min, keep 600r/min, press the “emergency shut down” button，check that HP-LP main throttle valve closed, rotate speed downgrade. Check turbine clash, listen sound of the cylinder inside, check that if the running part and static part have abnormal sound, check that if the rotor eccentricity normal, when eccentricity >0.075mm must forbid unit start. 5） After checking the friction, turbine latch again, the turbine rotate speed reach 600r/min, keep 600r/min,check the unit completely: a. Up and down gas side start with the turbine. b. Check bearing vibration, axial displacement ,differential expanse, cylinder absolute expansion, bearing metal temperature, return oil temperature, up and down cylinder differential temperature and so on in normal range. check eccentric recorder automatically disengage, vibration recorder begin to record the final rotor eccentric degree at rotate speed is 400～600r/min. c. Check condenser hot well level, deaerator water level, up and down feeding water level all adjusting put into automatic control and operating normally. d. Check turbine lube oil pressure and temperature, EH oil pressure and temperature, oil level of EH oil tank, bearing current are normal. e. Check the generator hydrogen pressure, hydrogen temperature, sealing oil pressure and hydrogen-oil differential pressure are normal. f.

Confirm the LP watering door open automatically, LP exhaust temperature is less than70℃,vacuum is normal.

g. If the gauge above parameters or close to the parameters and may rise, should report 2.4.3.6

immediately, identify the reason and prohibit to increase the speed. Continue to rise speed with target of 2000r/min

1） Click „Control set value‟ button on DEH screen and set speed rise rate of 150rpm/min with target speed of 2000r/min. Click „GO‟ button, turbine continues to rise speed. 2） Unit continues to rise speed to 2000r/min and keep running speed of 2000r/min for heating up turbine. During heating up, heat up pipes with auxiliary steam. 3） During speed rise, if running speed needs to stay, click the „HOLD‟ button in „Control set value‟ on screen. It is prohibited to stay in resonance running speed range to avoid turbine resonance. (1)700～900rpm (2)1300～1700rpm (3)2100～2300rpm 39

(4)2650～2850rpm 4） Heating up time should be decided according to first stage metal temperature, when this temperature is ≤120℃, heating up time should be 150min. Heat time should not be shortened under any condition. During medium speed heating up time, main steam temperature slowly slide to 380℃,reheated steam temperature slowly slide to 335℃(during this process, inlet steam can increase to 430℃,but the temperature rise rate can not more than 55℃/hour.) 5） During heating up, main steam temperature should not exceed 430℃ and reheating steam temperature should be higher than 300℃. Temperature rise should be controlled at 0.92℃/min. 6） During heating up, auxiliary equipments and systems should be checked completely, sounds in running parts are normal with no abnormal alarm. 7） After pipe heating, check and make sure that parameters for starting turbine are qualified and start the first steam driven pump with auxiliary steam according to actual conditions to avoid water impact. 8） The finishing condition of medium speed heating up : a. Make sure that time is up and heating up is completed. b. Check and make sure that steam cylinder is evenly expanded. c. HP & LP differential expansion decreases stably and gradually. d. Indications do not exceed limitation and are stable. 2.4.3.7

Turbine running speed rise from 2000r/min to 2900r/min, transfer the valves

1） Click „Control set value‟ button on DEH screen and set speed rise rate of 150rpm/min with target speed of 2900r/min. Click „GO‟ button, turbine continues to rise speed. 2） When turbine rotate speed is 2850r/min,check that jacking oil pump stop automatically, or stop manual, put into standby. 3） Running speed continues to rise to 2900 r/min and running speed keeps at 2900 r/min; it is ready for valve transfer. Make sure that inner wall temperature in steam chamber at least equals to saturation temperature under main steam pressure. See as annex of turbine inlet steam state which shows the relationship between inlet temperature and pressure of main steam valve in cold state start. If you want to make the temperature of steam chamber meet the required value, this parameter relationship should be obeyed. 4） „TV-GV‟ transfer operation “（TV/GV CHANGE）”button, GV will close slowly, TV/GV CHANGE IN PROGRESS in the information bar will bright, when GV close to certain valve, TV will open slowly when TV completely open, switch is finished, unit increase speed to 3000rpm automatically, “TV/GV CHANGE IN PROGRESS” become dark. During the recorder valve switching process, speed fluctuation value does not exceed 30r/min. 5）Check EH oil system, regulate that hydraulic mechanism of system is not leakage and abnormal, it can continue to increase the speed. 2.4.3.8

Unit running speed increase to 3000 r/min

1） Click „Control set value‟ button on DEH screen and set speed rise rate of 150r/min with target speed of 3000r/min. Click „GO‟ button. 2） Running speed continues to rise to 3000 r/min and running speed keeps at 3000 r/min. 3） After turbine operating in normal speed, completely check unit and each system is normal. a. Check and make sure that main oil pump outlet pressure is 2.0～2.5MPa and inlet oil pressure is 0.12～0.14MPa，main oil pump work normal. 40

b. Stop AC lubricate oil pump, sealing oil standby oil pump and put them in standby. c. Regulate lubricate oil temperature to be 38～42℃ and bearing returning oil temperature