Power System 1 Lab Manual
April 8, 2017 | Author: SufiSayyidZakiyah | Category: N/A
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POWER SYSTEM I ECB 3153 EXPERIMENT TITLE ________________________________ Name
:
Student ID
:
Group No
:
Lab Session
:
Date
:
Lecturer
:
GA’s
: : :
Rubric for Pre-Lab & In-Lab Course :
Power Systems
Date:
Student Name:
Student ID:
Topic (Weight)
Analysis and Preparation before experiment (2)
Knowledge & Understanding (3)
Safety & Health Issues
Unacceptable (0)
Punctuality (1) TOTAL
Examiner:
Acceptable (2)
Exceptional (3)
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❑
❑
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Demonstrated little or no ability to conduct experiments. Did not collect meaningful information.
No understanding of the topic and accurate answer to questions posed by instructor.
No understanding or appreciation of safety and health related issues
(1)
Participation in Teamwork (If applicable) (3)
Marginal (1)
Demonstrated little or no ability to function effectively as leader/team member during experimental work
>10 minutes late
Demonstrated some ability to conduct experiments. Collected some meaningful information.
Little understanding of the topic and accurate answer to questions posed by instructor.
Serious deficiencies in addressing health and safety issues leading to a unsupported and/or infeasible result
Demonstrated some ability to function effectively as leader/team member during experimental work
6-10 minutes late
Demonstrated adequate ability to conduct experiments. Collected most of the needed information.
Adequate understanding of the topic and accurate answer to questions posed by instructor.
Sound understanding of health and safety issues. Mostly effective in achieving supported results
Demonstrated adequate ability to function effectively as leader/team member during experimental work
1-5 minutes late
Demonstrated superior ability to conduct experiments. Collected all the appropriate information.
Excellent understanding of the topic and accurate answer to questions posed by instructor.
Complete understanding of health and safety issues leading to sound and supported results
Demonstrated superior ability to function effectively as leader/team member during experimental work
Punctual
Points
Rubric for Lab Report Course :
Power Systems
Date:
Student:
Student ID:
Topic (Weight) Introduction • Background • Objective • Scope
Unacceptable (0)
(3)
Results/Findings/Analysis (3)
Report Organization (2)
Acceptable (2)
Exceptional (3)
❑
❑
State the Able to state the introduction with introduction with limited minor error information
❑
Able to state the introduction clearly
❑
❑
❑
❑
❑
❑
❑
❑
❑
❑
❑
❑
Unable to state the introduction clearly
(2) Theoretical Knowledge/ Literature Review
Marginal (1)
Not explained or not related to the project
No results or plagiarized work are presented
Report is too difficult to understand with many grammatical error and not well organized
Not clearly explained or partially related to the project
Minimum results are presented and analyzed
Report is easy to understand with few grammatical error and moderately organized
Important knowledge are covered but still missing some important concept
Results are presented but with minor error and could still be improved
Report well written but occasionally some points are difficult to understand. Minor grammatical error
Points
❑
Clearly explained the knowledge and concept. Student capable of discussing the theory and simulated results
Results and analysis are clearly explained using relevant tool such as graph , table, etc.
Report very well written and easy to understand
TOTAL
Examiner:
One long report (hand written) will be assigned to each student which needs to submit one week after the respective lab is conducted. Punctuality is very important. The mark will be deducted to those are not punctual. Please follow all the lab safety and procedures. The formats of lab report are as follows: 1. Cover Page: Title of experiment, student name, matrix number and group number. 2. Report: Introduction, brief summary on how the experiment is done. 3. Conclusion: Brief conclusion and comments on the results obtained.
EXPERIMENT 1: SHUNT COMPENSATION POWER SYSTEM 1 ( ECB3153 )
PRE-LAB (2.5%) (1) What is a shunt compensation and why used in the transmission line? (2) How does shunt compensation work on the lines? (3) A shunt compensation as represented in single circuit below, determine what is the exactly capacitor size for each phase and what is the effect of reactive inductance in T.L.
(4) There are two types of compensation connections, series and shunt connections. Compare between them in terms of current, voltages, system loss, and real power. (5) Design a table for experiment data to show the characteristics of the voltage and reactive load.
1|Page
EXPERIMENT 1: SHUNT COMPENSATION POWER SYSTEM 1 ( ECB3153 )
EQUIPMENT MANUAL (2.5%) In order to do the experiment you have to follow these instructions and procedures; 1. At (C1), put the speed control and voltage control potentiometer COARSE in minimum. 2. Put the speed control and voltage control potentiometer FINE on 50 percent 3. Put the switch for START/RUN in position start (only this is possible for starting the machine). 4. Put the switch for the DC converter CBM1 in ON position. The machines will now speed up to basic speed. During the acceleration a warning bell will sound and the ammeter IA will jump up to several amp (for a couple of seconds). 5. Adjust the speed control potentiometer COARSE and FINE to a position that will give a speed close to 1500 rpm. 6. Put the CB for the DC converter CBF1 in ON position. Then witch on isolator I1 or I2. 7. Switch on circuit breaker CB1. The power is transmitted either through line A230 orB230 depending on which isolator is switched on. 8. At (C3), adjust the voltage potentiometer COARSE and FINE until the outgoing lines have approximately 240 V at no load as indicated in the meter. 9. At cubicle C3, switch on I5 or I6. Then switch on I9 and then CB3 10. Voltage, current and power readings can also be observed in the digital meter connected. 11. At (C12), take down the readings (meter) of voltage and reactive power at no load. 12. Increase the variable inductive load without compensation. i.e move the switch of the inductive load to position 1 to 6, and record the readings of voltage, load current, and reactive power.
2|Page
EXPERIMENT 1: SHUNT COMPENSATION POWER SYSTEM 1 ( ECB3153 )
13. Now move the variable capacitive switch to position 1. Shunt compensation is applied to the circuit. Repeat step 14 for different values of compensation applies the load and record the reading at each case.
SYSTEM COMPONENTS:
3|Page
EXPERIMENT 1: SHUNT COMPENSATION POWER SYSTEM 1 ( ECB3153 )
OBSERVATIONS For different values of compensation apply the load and record the readings.
TABLE (1) Receiving End Volts (V)
Amp (I)
Real Power
Load (Var)
(W)
Serial
Receiving End
TABLE (2) Compensation
In load
No.
Load current
Volts (V)
Reactive
(Var)
(Var)
0
OFF
OFF
1
OFF
1
2
OFF
2
3
OFF
3
4
OFF
4
5
OFF
5
6
OFF
6
(A)
Power (Q)
4|Page
EXPERIMENT 1: SHUNT COMPENSATION POWER SYSTEM 1 ( ECB3153 )
Serial No.
TABLE (3) Receiving End Compensation In load Volts (V)
Reactive Power (Var)
0 1 2 3 4 5 6
(Var)
(Var)
0 1 2 3 4 5 6
0 1 2 3 4 5 6
Load current (A)
Fill table (4), by connecting 3 phase induction motor as in Pre-Lab as star connection to the shunt compensation terminals, and try to increase the compensation of position 1 to position 4,
TABLE (4) Serial No.
Receiving End Volts (V)
0 1 2 3 4
Reactive Power (Var)
Compensation In load (Var)
(Var)
0 240 480 720 960
OFF OFF OFF OFF OFF
Load current (A)
5|Page
EXPERIMENT 1: SHUNT COMPENSATION POWER SYSTEM 1 ( ECB3153 )
LAB (5%) OBJECTIVE To study the effect of mid-point shunt compensation on power transfer capability in a transmission line. CIRCUIT DIAGRAM
On long transmission lines heavy loads produce a large dip in voltage. Shunt capacitors are used to improve voltage, increase power transfer and improve the system stability. Capacitors are connected either directly to a bus bar or to the tertiary winding of a main transformer and are disposed along the route to minimize the losses and voltage drops. Shunt capacitors are used for lagging power factor circuits created by heavy loads. The effect is to supply the requisite reactive power to maintain the receiving end voltage at a satisfactory level. TASK 1. Perform experiment to show that power transfer to the load increases as increasing shunt compensation. Show your results at any a table as represented in plotted graphs. 2. What is the relationship between the load current and the reactive load? 3. Draw a schematic diagram of shunt compensation experiment.
6|Page
POWER SYSTEM I ECB 3153 EXPERIMENT TITLE ________________________________ Name
:
Student ID
:
Group No
:
Lab Session
:
Date
:
Lecturer
:
GA’s
: : :
Rubric for Pre-Lab & In-Lab Course :
Power Systems
Date:
Student Name:
Student ID:
Topic (Weight)
Analysis and Preparation before experiment (2)
Knowledge & Understanding (3)
Safety & Health Issues
Unacceptable (0)
Punctuality (1) TOTAL
Examiner:
Acceptable (2)
Exceptional (3)
❑
❑
❑
❑
❑
❑
❑
❑
❑
❑
❑
❑
❑
❑
❑
❑
❑
❑
❑
❑
Demonstrated little or no ability to conduct experiments. Did not collect meaningful information.
No understanding of the topic and accurate answer to questions posed by instructor.
No understanding or appreciation of safety and health related issues
(1)
Participation in Teamwork (If applicable) (3)
Marginal (1)
Demonstrated little or no ability to function effectively as leader/team member during experimental work
>10 minutes late
Demonstrated some ability to conduct experiments. Collected some meaningful information.
Little understanding of the topic and accurate answer to questions posed by instructor.
Serious deficiencies in addressing health and safety issues leading to a unsupported and/or infeasible result
Demonstrated some ability to function effectively as leader/team member during experimental work
6-10 minutes late
Demonstrated adequate ability to conduct experiments. Collected most of the needed information.
Adequate understanding of the topic and accurate answer to questions posed by instructor.
Sound understanding of health and safety issues. Mostly effective in achieving supported results
Demonstrated adequate ability to function effectively as leader/team member during experimental work
1-5 minutes late
Demonstrated superior ability to conduct experiments. Collected all the appropriate information.
Excellent understanding of the topic and accurate answer to questions posed by instructor.
Complete understanding of health and safety issues leading to sound and supported results
Demonstrated superior ability to function effectively as leader/team member during experimental work
Punctual
Points
Rubric for Lab Report Course :
Power Systems
Date:
Student:
Student ID:
Topic (Weight) Introduction • Background • Objective • Scope
Unacceptable (0)
(3)
Results/Findings/Analysis (3)
Report Organization (2)
Acceptable (2)
Exceptional (3)
❑
❑
State the Able to state the introduction with introduction with limited minor error information
❑
Able to state the introduction clearly
❑
❑
❑
❑
❑
❑
❑
❑
❑
❑
❑
❑
Unable to state the introduction clearly
(2) Theoretical Knowledge/ Literature Review
Marginal (1)
Not explained or not related to the project
No results or plagiarized work are presented
Report is too difficult to understand with many grammatical error and not well organized
Not clearly explained or partially related to the project
Minimum results are presented and analyzed
Report is easy to understand with few grammatical error and moderately organized
Important knowledge are covered but still missing some important concept
Results are presented but with minor error and could still be improved
Report well written but occasionally some points are difficult to understand. Minor grammatical error
Points
❑
Clearly explained the knowledge and concept. Student capable of discussing the theory and simulated results
Results and analysis are clearly explained using relevant tool such as graph , table, etc.
Report very well written and easy to understand
TOTAL
Examiner:
One long report (hand written) will be assigned to each student which needs to submit one week after the respective lab is conducted. Punctuality is very important. The mark will be deducted to those are not punctual. Please follow all the lab safety and procedures. The formats of lab report are as follows: 1. Cover Page: Title of experiment, student name, matrix number and group number. 2. Report: Introduction, brief summary on how the experiment is done. 3. Conclusion: Brief conclusion and comments on the results obtained.
EXPERIMENT 2: TRANSMISSION PARAMETERS POWER SYSTEM 1 ( ECB3153 )
PRE-LAB(2.5%) ANSWER FOLLOWING 1. How transmission and inverse transmission line parameters are determined; explain the two tests required to determine these parameters
2. What is the necessity to obtain transmission parameters?
3. Explain following block diagram and describe the transmission and inverse transmission line parameters in terms of two-port network and explain the relationship for all parameters.
Figure: Two port representation of transmission line
4. Why inverse transmission parameters are determined.
5. Design a table that includes variables, those should be measured and recorded in order to achieve transmission and inverse transmission parameters.
1|Page
EXPERIMENT 2: TRANSMISSION PARAMETERS POWER SYSTEM 1 ( ECB3153 )
EQUIPMENT OPERATING MANUAL (2.5%) Transmission Parameters Open-circuit test: To determine A and C, the output side of the transmission line network is open-circuited to make I R = 0 . The input side is supplied with source voltage (equal to 400V the nominal value ) keeping the impedance of the transmission line at some value. Short-circuit test: The output port is short-circuited to make VR = 0 . The input port is supplied with low voltage and adjusted until nominal current (check the rated value of the current on the three phase transmission line board) is attained. By measuring the voltages and current the required parameters are calculated. Warning :
High voltages are present in this Laboratory! Do not make any connections with the power on. The module must be connected to a three-phase variable 0240/415 V power supply, labeled 4, 5, 6 and N.
Open-circuit test 1) To connect the three phase transmission line circuit to the power supply. The terminals (4, 5, and 6, variable voltage supply) of power supply should be connected to terminals (1,2 and 3) of the three phase transmission line. 2) Place and ammeter in between the terminals 4 (of the power supply) and 1 (of the transmission line). 3) Set the value of transmission impedance to zero. 4) Connect a voltmeter in between 4 and 5or5 and 6or4 and 6 of the power supply to measure sending end voltage VS. Since the measured voltages between any two terminals is equal. 5) Connect a voltmeter in between 4 and 5or5 and 6or4 and 6 of the three phase transmission line to measure receiving end voltage VR .(figure 2) 6) Apply the power supply and increase the connected three-phase supply variable voltage slowly from zero. All the meters should read positive. If not interchange the terminals of the respective meters .With the output port open, adjust the voltage of the source so the line to line voltage is 400 V. 7) Record the voltages and current values in the table. 8) Turn down the source voltage to zero. 2|Page
EXPERIMENT 2: TRANSMISSION PARAMETERS POWER SYSTEM 1 ( ECB3153 )
9) Set the line impedance to 200 ohms 10) Repeat the experiment for line impedances of 200, 400, and 600 ohms. Short-circuit test 1) Using the same setup as mentioned above, but short the terminals 4, 5 and 6 of the transmission line through an ammeter. (figure 3) 2) Apply the power and increase the connected three phase voltage slowly and very carefully from zero until nominal current is reached. Record the results in the table. 3) For ’0’ transmission impedances do not go to nominal voltage. Just take 0.5V at this value the current around 5A. 4) Turn the voltage to zero and shut the power supply. 5) Repeat the experiment for different line impedances. TABLE I. MEASURMENTS Impedance Ω
Open-circuit test VS IS IR VR volt
amp
amp
volt
Short-circuit test VS IS IR VR volt
amp
amp
volt
0
0
0
200
0
0
400
0
0
600
0
0
Transmission parameters A B C D Siemens (Ω )
3|Page
EXPERIMENT 2: TRANSMISSION PARAMETERS POWER SYSTEM 1 ( ECB3153 )
Inverse Transmission Parameters Open-circuit test: To determine ‘a’ and ‘c’, the input port is open-circuited to make I S = 0 . The output port is supplied with source and voltage of 220 V is applied keeping the impedance of the transmission line at some value. Short-circuit test: The input port is short-circuited to make VS = 0 . The output port is supplied with low voltage and adjusted until nominal current is attained. By measuring the voltages and current the required parameters are calculated. Open-circuit test 1) Connect the circuit to the power supply. The terminals 4,5,and 6 of power supply should be connected to 4,5 and 6 of the three phase transmission line. 2) Set the value of transmission impedance to zero. 3) Place and ammeter in between the terminals 4 (of the power supply) and 4 (of the transmission line). 4) Connect a voltmeter in between 1 and 2 or 2 and 3 or 1 and 3 of the transmission line to measure receiving end voltage VR . The input port is left open. 5) Connect a voltmeter in between 4 and 5 or 5 and 6 or 4 and 6 of the power supply to measure sending end voltage VS 6) Apply the power supply and increase the connected three-phase supply slowly from zero. All the meters should read positive. With the input port open, adjust the voltage of the source so the line to line voltage is 400 V. 7) Record the voltages and current values in the table. 8) Turn down the source voltage to zero 9) Set the line impedance to 200 ohms 10) Repeat the experiment for line impedances of 200, 400, and 600 ohms.
4|Page
EXPERIMENT 2: TRANSMISSION PARAMETERS POWER SYSTEM 1 ( ECB3153 )
Short-circuit test 1) Using the same setup as mentioned above, short the terminals 1, 2 and 3 of the transmission line through an ammeter. 2) Apply the power and increase the connected three phase voltage slowly and very carefully from zero until nominal current is reached. Record the results in the table 3) For ’0’ transmission impedances do not go to nominal voltage. Just take 0.5V at this value the current around 5A. 4) Turn the voltage to zero and shut the power supply. 5) Repeat the experiment for different line impedances. TABLE II. MEASURMENTS Impedance
Open-circuit test
0
IS amp 0
200
0
0
400
0
0
600
0
0
Ω
VS volt
IR amp
VR volt
Inverse Transmission parameters
Short-circuit test VS volt 0
IS amp
IR amp
VR volt
a
b (Ω )
b Siemens
d
5|Page
EXPERIMENT 2: TRANSMISSION PARAMETERS POWER SYSTEM 1 ( ECB3153 )
LAB(2.5%) Objective By using following equipments, conduct the experiment to determine the transmission and inverse transmission parameters. Required Equipment Model
Description
8821 8329 8426 8425 9128
Power supply unit Three-Phase Transmission Line AC Voltmeter AC Ammeter Connection Leads
Quantity 1 1 2 2
Theory TRANSMISSION PARAMETERS The transmission line for determining transmission parametersmay be represented by a two port network as shown in Figure.01
Figure.01 Transmission line representation for transmission parameters
V S = AV R + BI R I S = CV R + DI R Where VR:Receiving End voltage
IR:Receiving End currentVS:Sending End voltage
IS: Sending End voltage
The two-port parameters provide a measure of how a circuit transmits voltage and current from a source to a load. They are called transmission parameters or A, B, C, and D parameters. The transmission parameters are determined as I V I V A= S B= S C= S D= S VR I R = 0 VR I R = 0 I R VR = 0 I R VR = 0 The transmission parameters are called, specifically A = Open-circuit voltage ratio B = Negative short – circuit transfer impedance C = Open-circuit transfer admittance D = Negative short – circuit current ratio
6|Page
EXPERIMENT 2: TRANSMISSION PARAMETERS POWER SYSTEM 1 ( ECB3153 )
A and D are dimensionless, B is in ohms and C is in siemens. The parameters are obtained by open-circuit and short-circuit test INVERSE TRANSMISSION PARAMETERS The transmission line for determining inverse transmission parametersmay be represented by a two port network as shown in Figure.02
Figure.02 Transmission line representation for inverse transmission parameters
V R = aV S + bI S I R = cV S + dI S Where VR:Receiving End voltage
IR: Receiving End currentVS:Sending End voltage
IS: Sending End voltage
The parameters a, b, c and d are called the inverse transmission parameters. They are determined as follows a=
VR I V I b= R c= R d = R VS I S = 0 VS I S = 0 I S VS = 0 I R VS = 0
The transmission parameters are called, specifically a = Open-circuit voltage gain b = Negative short – circuit transfer impedance c = Open-circuit transfer admittance d = Negative short – circuit current gain
a and d are dimensionless, b is in ohms and c is in siemens. The parameters are obtained by open-circuit and short-circuit test Tasks •
Draw the schematic diagram of open-circuit and short-circuit test for transmission and inverse transmission parameters.
•
Draw the table of all the variables measured and recorded during laboratory experiment for transmission and inverse transmission parameters.
•
Calculate transmission parameters (A, B, C, and D) and inverse transmission parameters (a, b, c, and d) by open-circuit and short-circuit tests.
7|Page
POWER SYSTEM I ECB 3153 EXPERIMENT TITLE ________________________________ Name
:
Student ID
:
Group No
:
Lab Session
:
Date
:
Lecturer
:
GA’s
: : :
Rubric for Pre-Lab & In-Lab Course :
Power Systems
Date:
Student Name:
Student ID:
Topic (Weight)
Analysis and Preparation before experiment (2)
Knowledge & Understanding (3)
Safety & Health Issues
Unacceptable (0)
Punctuality (1) TOTAL
Examiner:
Acceptable (2)
Exceptional (3)
❑
❑
❑
❑
❑
❑
❑
❑
❑
❑
❑
❑
❑
❑
❑
❑
❑
❑
❑
❑
Demonstrated little or no ability to conduct experiments. Did not collect meaningful information.
No understanding of the topic and accurate answer to questions posed by instructor.
No understanding or appreciation of safety and health related issues
(1)
Participation in Teamwork (If applicable) (3)
Marginal (1)
Demonstrated little or no ability to function effectively as leader/team member during experimental work
>10 minutes late
Demonstrated some ability to conduct experiments. Collected some meaningful information.
Little understanding of the topic and accurate answer to questions posed by instructor.
Serious deficiencies in addressing health and safety issues leading to a unsupported and/or infeasible result
Demonstrated some ability to function effectively as leader/team member during experimental work
6-10 minutes late
Demonstrated adequate ability to conduct experiments. Collected most of the needed information.
Adequate understanding of the topic and accurate answer to questions posed by instructor.
Sound understanding of health and safety issues. Mostly effective in achieving supported results
Demonstrated adequate ability to function effectively as leader/team member during experimental work
1-5 minutes late
Demonstrated superior ability to conduct experiments. Collected all the appropriate information.
Excellent understanding of the topic and accurate answer to questions posed by instructor.
Complete understanding of health and safety issues leading to sound and supported results
Demonstrated superior ability to function effectively as leader/team member during experimental work
Punctual
Points
Rubric for Lab Report Course :
Power Systems
Date:
Student:
Student ID:
Topic (Weight) Introduction • Background • Objective • Scope
Unacceptable (0)
(3)
Results/Findings/Analysis (3)
Report Organization (2)
Acceptable (2)
Exceptional (3)
❑
❑
State the Able to state the introduction with introduction with limited minor error information
❑
Able to state the introduction clearly
❑
❑
❑
❑
❑
❑
❑
❑
❑
❑
❑
❑
Unable to state the introduction clearly
(2) Theoretical Knowledge/ Literature Review
Marginal (1)
Not explained or not related to the project
No results or plagiarized work are presented
Report is too difficult to understand with many grammatical error and not well organized
Not clearly explained or partially related to the project
Minimum results are presented and analyzed
Report is easy to understand with few grammatical error and moderately organized
Important knowledge are covered but still missing some important concept
Results are presented but with minor error and could still be improved
Report well written but occasionally some points are difficult to understand. Minor grammatical error
Points
❑
Clearly explained the knowledge and concept. Student capable of discussing the theory and simulated results
Results and analysis are clearly explained using relevant tool such as graph , table, etc.
Report very well written and easy to understand
TOTAL
Examiner:
One long report (hand written) will be assigned to each student which needs to submit one week after the respective lab is conducted. Punctuality is very important. The mark will be deducted to those are not punctual. Please follow all the lab safety and procedures. The formats of lab report are as follows: 1. Cover Page: Title of experiment, student name, matrix number and group number. 2. Report: Introduction, brief summary on how the experiment is done. 3. Conclusion: Brief conclusion and comments on the results obtained.
EXPERIMENT 3: ALTERNATOR SYNCHRONIZATION POWER SYSTEM 1 ( ECB3153 )
PRE-LAB (2.5%) OBJECTIVE To understand the general concept of an alternator sycrhonization with an existing power system grid. PRE-LAB QUESTIONS 1. What do you understand by alternator synchronization with power system grid? 2. Why do we need alternator synchronization in power system grid? 3. What are the necessary conditions to synchronize our alternator with an existing power system grid? 4. An alternator could be severely damaged mechanically in attempting to synchronize it with the power line. Under what two conditions could this happen? 5. An alternator generating a different value of voltage also may not be exactly in phase with the power line. But one condition must be met in order for it to deliver power. What is that condition?
1|Page
EXPERIMENT 3: ALTERNATOR SYNCHRONIZATION POWER SYSTEM 1 ( ECB3153 )
EQUIPMENT MANUAL (2.5%) OPERATING PROCEDURES In order to do the experiment you have to follow these instructions and procedures; 1. a) Connect your DC Motor/Generator and your Synchronous Motor/ Generator to their respective wiring modules and then couple them using a rubber coupler. b) Install your Electrical Tachometer on one of the two machines. 2. a) Using your Power Supply Module, your Wiring Module for DC Motor Generator, your Wiring Module for Synchronous Motor/Generator, two Field Rheostat Modules, your DC Metering Module, your AC Ammeter Module, your AC Voltmeter Module, and your Synchronizing Module, connect the circuit shown in Figure 1. b) Note that the output of the alternator is connected through the synchronizing switch to the fixed, 415 V ac. 3 phase output of the power supply (terminals 1, 2 and 3). c) Note that the rotor of the alternator is connected to the fixed 220 V dc output of the power supply (terminals 8 and N). d) Note that the dc shunt motor is connected to the variable 0-220 V dc output of the power supply (terminals 7 and N). 3. a) Set the dc motor field rheostat at its full cw position (for minimum resistance). b) Set the alternator field rheostat at its full ccw position (for maximum resistance). c) Make sure that the synchronizing breaker is in its open position. d) Open the toggle switch in the excitation circuit of the alternator. e) Make sure that the power supply control knob is at zero. 4. a) Turn on the power supply and adjust the variable dc voltage of the power supply to 220 V dc (use your power supply meter with the selector switch in position 7-N).
2|Page
EXPERIMENT 3: ALTERNATOR SYNCHRONIZATION POWER SYSTEM 1 ( ECB3153 )
b) Using your electrical tachometer adjust the dc motor field rheostat for a speed of approximately 1500 r/min. c) Measure the power supply fixed ac voltage E2. d) Close the toggle switch of the alternator excitation circuit. e) Adjust the dc excitation of the alternator until the alternator output voltage EI is equal to E2. Note: These two voltages must be kept equal for the remainder of this Laboratory Experiment. f) The three synchronizing lights should be flickering on and off.
415 Vac
Figure 1: System Components
3|Page
EXPERIMENT 3: ALTERNATOR SYNCHRONIZATION POWER SYSTEM 1 ( ECB3153 )
5. a) Carefully adjust the dc motor speed until the beat frequency becomes quite low. b) Observing all three lights become bright and then dark, at the same time. Yes
No
c) If they do not all become dark and then bright simultaneously, the phase sequence is wrong, Turn off the supply and interchange any two of the leads coming from the stator. Set the dc motor field rheostat at its full cw position and the alternator field rheostat at its full ccw position again. d) Carefully adjust the rotor speed until all three lights slowly darken and then slowly brighten. Your alternator frequency is very nearly equal to that of the power company. e) When all of the light are completely dark, the alternator and supply voltages are in phase. I) When all of the light are fully bright, the alternator and supply voltages are 180 degrees out of phase. (This is the "tooth-to-tooth" condition, and the synchronizing switch should never be closed under these conditions). g) Check to see that the two voltages EI and E2 are equal. If not, readjust the dc excitation to the alternator.
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EXPERIMENT 3: ALTERNATOR SYNCHRONIZATION POWER SYSTEM 1 ( ECB3153 )
OBSERVATIONS AND MEASUREMENTS 1. With the synchronizing conditions in case of E1 is equal to E2. a) Close the synchronizing breaker when all three lights are dark and note the behavior of I1 at the moment of closure. b) Close the synchronizing breaker when all three lights are dim and note the behavior of I1 at the moment of closure. c) Close the synchronizing breaker when all three lights are partially bright and note the behavior of I1 at the moment of closure. 2. With the synchronizing breaker open, adjust the dc excitation to the alternator until the output voltage E1 = 450 Vac. Close the synchronizing breaker when all three lights are dimmed completely and note the effect upon I1 at the moment of closure and after closure. 3. Reverse the rotation of the dc motor by interchanging the shunt field and then attempt to synchronize the alternator as before.
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EXPERIMENT 3: ALTERNATOR SYNCHRONIZATION POWER SYSTEM 1 ( ECB3153 )
LAB (5%) OBJECTIVE To learn how to synchronize an alternator to the electric power utility system. To observe the effects of improper phase conditions upon the synchronizing process. THEORY The frequency of a large electric power utility system is established by the speed of rotation of many powerful alternators all connected by various tie-lines into the total network. The collective inertia and power of these generators is so great that there is no single load or disturbance which would be large enough to change their speed of rotation. The frequency of an electric system is therefore remarkably stable. An alternator can only deliver power to an existing electric power system if it operates at the same frequency as the system. They must both operate at exactly the same frequency. This is not as difficult to realize as may first appear, because automatic forces come into play when an alternator is connected into an existing system to keep its frequency constant. Synchronization of an alternator with a large utility system. or "infinite bus" as it is called is analogous to meshing a small gear to another of enormous size and power. If the teeth of both gears are properly synchronized at the moment of contact. then the meshing will be smooth. But should tooth meet tooth at the critical instant shock will result with possible damage to the smaller gear. Smooth synchronization of an alternator means first that its frequency must be equal to that of the supply. In addition, the phase sequence (or rotation) must be the same. Returning to our example of the gears. we would not think of trying to mesh two gears going in opposite directions, even if their speeds were identical. The next thing to watch for when we push gears together is to see that the tooth of one meets the slot of the other. In electrical terms the voltage of the alternator must be in phase with the voltage of the supply.
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EXPERIMENT 3: ALTERNATOR SYNCHRONIZATION POWER SYSTEM 1 ( ECB3153 )
Finally, when meshing gears we always choose a tooth depth which is compatible with the master gear. Electrically, the voltage amplitude of the alternator should be equal to the supply voltage amplitude. With these conditions met, the alternator is perfectly synchronized with the network and the switch between the two can be closed. TASKS 1. Perform pre-synchronizing experiment to witness synchronizing lights conditions for wrong phase sequence between the alternator and power supply and discuss your findings 2. Conduct pre-synchronizing experiment to witness synchronizing lights conditions when the alternator and supply voltages are in phase and out of phase and discuss your findings 3. Conduct correct synchronizing experiment between the alternator and supply voltages and discuss your findings
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POWER SYSTEM I ECB 3153 EXPERIMENT TITLE ________________________________ Name
:
Student ID
:
Group No
:
Lab Session
:
Date
:
Lecturer
:
GA’s
: : :
Rubric for Pre-Lab & In-Lab Course :
Power Systems
Date:
Student Name:
Student ID:
Topic (Weight)
Analysis and Preparation before experiment (2)
Knowledge & Understanding (3)
Safety & Health Issues
Unacceptable (0)
Punctuality (1) TOTAL
Examiner:
Acceptable (2)
Exceptional (3)
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❑
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Demonstrated little or no ability to conduct experiments. Did not collect meaningful information.
No understanding of the topic and accurate answer to questions posed by instructor.
No understanding or appreciation of safety and health related issues
(1)
Participation in Teamwork (If applicable) (3)
Marginal (1)
Demonstrated little or no ability to function effectively as leader/team member during experimental work
>10 minutes late
Demonstrated some ability to conduct experiments. Collected some meaningful information.
Little understanding of the topic and accurate answer to questions posed by instructor.
Serious deficiencies in addressing health and safety issues leading to a unsupported and/or infeasible result
Demonstrated some ability to function effectively as leader/team member during experimental work
6-10 minutes late
Demonstrated adequate ability to conduct experiments. Collected most of the needed information.
Adequate understanding of the topic and accurate answer to questions posed by instructor.
Sound understanding of health and safety issues. Mostly effective in achieving supported results
Demonstrated adequate ability to function effectively as leader/team member during experimental work
1-5 minutes late
Demonstrated superior ability to conduct experiments. Collected all the appropriate information.
Excellent understanding of the topic and accurate answer to questions posed by instructor.
Complete understanding of health and safety issues leading to sound and supported results
Demonstrated superior ability to function effectively as leader/team member during experimental work
Punctual
Points
Rubric for Lab Report Course :
Power Systems
Date:
Student:
Student ID:
Topic (Weight) Introduction • Background • Objective • Scope
Unacceptable (0)
(3)
Results/Findings/Analysis (3)
Report Organization (2)
Acceptable (2)
Exceptional (3)
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State the Able to state the introduction with introduction with limited minor error information
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Able to state the introduction clearly
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Unable to state the introduction clearly
(2) Theoretical Knowledge/ Literature Review
Marginal (1)
Not explained or not related to the project
No results or plagiarized work are presented
Report is too difficult to understand with many grammatical error and not well organized
Not clearly explained or partially related to the project
Minimum results are presented and analyzed
Report is easy to understand with few grammatical error and moderately organized
Important knowledge are covered but still missing some important concept
Results are presented but with minor error and could still be improved
Report well written but occasionally some points are difficult to understand. Minor grammatical error
Points
❑
Clearly explained the knowledge and concept. Student capable of discussing the theory and simulated results
Results and analysis are clearly explained using relevant tool such as graph , table, etc.
Report very well written and easy to understand
TOTAL
Examiner:
One long report (hand written) will be assigned to each student which needs to submit one week after the respective lab is conducted. Punctuality is very important. The mark will be deducted to those are not punctual. Please follow all the lab safety and procedures. The formats of lab report are as follows: 1. Cover Page: Title of experiment, student name, matrix number and group number. 2. Report: Introduction, brief summary on how the experiment is done. 3. Conclusion: Brief conclusion and comments on the results obtained.
EXPERIMENT 4: REAL POWER AND REACTIVE POWER POWER SYSTEM 1 (ECB3153) .
PRE-LAB (2.5%) OBJECTIVE To understand the general concept of the power flow in a power system Grid.
PRE-LAB QUESTIONS How does can observe the flow of real and reactive power in a three-phase circuits? When the current will be lagging, leading and when will be in-phase with the voltage? Explain why the reactive power is needed? What is your expectation if the power flows in the direction of the input terminals from the output terminals? What does the real power accomplish? and what does the reactive power accomplish?
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EXPERIMENT 4: REAL POWER AND REACTIVE POWER POWER SYSTEM 1 (ECB3153) .
EQUIPMENT MANUAL (2.5%) OPERATING PROCEDURES In order to do the experiment you have to follow these instructions and procedures; 1. The experiment involve a three-phase source provides a voltage of about 415 V with terminals 4, 5, 6, one voltmeter, three Ammeters, one Three-Phase Wattmeter/Varmeter, should connect it to AC 24 V source, and a balanced three-phase star-connected load. 2. Using a load of 1200 from each of the three Resistive Loads as shown in Figure 1, measure E, I, P, Q and record your results in Table 1.
FIGURE 1 3. Replace the Resistive Load by three Inductive Loads having a reactance of 1200 Ω. Record your results in Table 1. 4. Repeat procedure step 3, using three Capacitive Loads having a reactance of 1200 Ω. Record your results in Table 1. 5. Repeat procedure step 4, but add three Resistive Loads of 1200 Ω (star- connected) in parallel with the Capacitive Loads. Record your results in Table 1. 6. Repeat procedure step 2, but place the Inductive Load of procedure step 3 in parallel with the Resistive Loads. Record your results in Table 1. 7. Repeat procedure step 2, but use an Inductive Load of 1200 Ω in parallel with a Capacitive Load of 1200 Ω, all star-connected. Record your results in Table 1. 8. Repeat procedure step 2, but use a Three-Phase Wound-Rotor Induction Motor at no load instead of the Resistive Load as shown in Figure 2. Record your results in Table 1.
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EXPERIMENT 4: REAL POWER AND REACTIVE POWER POWER SYSTEM 1 (ECB3153) .
Three-phase Wound-Rotor Induction Motor FIGURE 2 Table 1
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EXPERIMENT 4: REAL POWER AND REACTIVE POWER POWER SYSTEM 1 (ECB3153) .
OBSERVATIONS AND MEASUREMENTS 1. In procedure step 5, is the real power affected when the Capacitive Loads are switched on and off? Yes
No
2. In procedure step 5, is the reactive power affected when the Resistive Loads are switched on and off? Yes
No
3. Why the real power is slightly affected when the Inductive Loads are switched on and off, in procedure step 6?
4. In procedure step 6, is the reactive power affected when the Resistive Loads are switched on and off? Yes
No
5. In procedure step 7, do you agree that, to all intents and purposes, the Capacitive Load is supplying most of the reactive power required by the Inductive Load? Yes
No
6. From procedure step 7, would you agree that the Capacitive Load can be considered to be a source of reactive power? Yes
No
7. From procedure step 8, does the motor absorb both real and reactive power? Yes
No
8. Knowing that the apparent power (S) in volt-amperes (VA) is given by the expression S = P 2 + Q 2 , calculate the apparent power in Table 1. 4|Page
EXPERIMENT 4: REAL POWER AND REACTIVE POWER POWER SYSTEM 1 (ECB3153) .
LAB (5%) OBJECTIVE To interpret the meaning of positive, negative, real and reactive power.
To observe the flow of real and reactive power in three-phase circuits.
THEORY In direct current circuits the real power (in watts) supplied to a load is always equal to the product of the voltage and the current. In alternating current circuits, however, this product is usually greater than the real (or active) power which the load consumes. For this reason, wattmeters are used to measure the real power (in watts). In three-phase, three-wire AC circuits two wattmeters are needed to measure the real power while three-phase, four-wire circuits require three. These meters may be combined into a single wattmeter of special construction, which greatly simplifies the problem of adding the readings of two or three wattmeters to obtain the total three-phase power. A typical three-phase wattmeter (Figure 1) has three input terminals (1, 2, 3) and three output terminals (4, 5, 6).
FIGURE 1 If the wattmeter is connected into a three-phase line, as shown in Figure 1, it will show the total real power flowing in the line. if the power flows in the direction of the input terminals to the output terminals (left to right in Figure 1) the meter pointer will be deflected to the right and the reading will be positive. However, if power flow is from right to left, that is, from the output terminals to the input terminals, the meter pointer will be deflected to the left and the reading will be negative. Real power, therefore, is positive or negative according to its direction of flow. The direction of power flow can easily be found when the "input" terminals have been identified.
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EXPERIMENT 4: REAL POWER AND REACTIVE POWER POWER SYSTEM 1 (ECB3153) .
Reactive power is the power associated with the charge and discharge of condensers and the increase and decrease of the magnetic fields of inductors when they are part of an alternating current circuit. Because the energy (joules) in a coil merely builds up and decays as the magnetic field increases and decreases in response to the alternating current which it carries, it follows that there is no flow of real power in a coil. On the other hand, a current flows through the coil and a voltage appears across it, so a casual observer is apt to believe that power of some kind is involved. The product of the voltage and current in a coil is called the reactive power, and it is expressed in var or in kilovar (kvar). Reactive power is needed to produce an alternating magnetic field. In the same way, the alternating electric field in a capacitor also requires reactive power. Owing to the overwhelming prevalence of electromagnetic devices (as opposed to electrostatic devices), we consider that reactive power, whenever it appears, is the kind of power which has the ability to produce a magnetic field. Reactive power, just like real power, can be measured with appropriate meters called varmeters. In three-phase circuits, the two or three varmeters which would ordinarily be needed can be combined into a single instrument to give one reading of the total reactive power flow in the circuit. Such a meter, shown in Figure 2, possesses three input terminals (1, 2, 3) and three output terminals (4, 5, 6).
FIGURE 2 When reactive power flows from the input to the output terminals, the meter will give a positive reading. Conversely, if the flow of reactive power is from the output terminals to the input terminals, a negative reading will result. For example, if a three- phase source and a three-phase coil are connected as shown in Figure 3, the flow of reactive power is obviously from left to right, and the varmeter will give a positive reading. Just as with a wattmeter, the direction of reactive power flow can readily be found when the input terminals of the varmeter are identified.
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EXPERIMENT 4: REAL POWER AND REACTIVE POWER POWER SYSTEM 1 (ECB3153) .
FIGURE 3
Three-phase alternating circuits may involve many types of circuits and devices, but the flow of active and reactive power can always be determined by introducing wattmeters and varmeters. The example of Figure 4 will illustrate how some typical readings can be interpreted. An impedance Z forms part of a larger circuit (not shown), and wattmeters W1, W 2 and varmeters var1, var2 are connected on either side. The input terminals are assumed to be on the left-hand side of each instrument. The meters give the following readings:
FIGURE 4
W1 = +70 W W2 = -40 W
var1 = -60 var var2 = -80 var
How are we to interpret these results? First, we must recognize that real power and reactive power flow quite independently of each other. One does not affect the other. Consequently, we must never add or subtract real power and reactive power. Consider first the active power. Because W, is positive. real power is flowing to the right. Because W2 is negative. real power is flowing to the left. It follows, therefore, that the impedance Z must be absorbing 70 + 40 = 110 W. Next, let us look at the reactive power; 80 var are flowing to the left, towards the impedance Z, while 60 var are flowing to the left, away from it. It follows that Z is absorbing (80 -60) = 20 var, and this reactive power creates a magnetic field. This example shows that when wattmeters and varmeters are connected on either side of an electrical circuit or device, we can determine the real and the reactive power which it produces or absorbs. 7|Page
EXPERIMENT 4: REAL POWER AND REACTIVE POWER POWER SYSTEM 1 (ECB3153) .
TASK 1. An electrical load Z is connected to the terminals of a 240 V ac source. Show the direction of real and reactive power flow if Z is a) a resistor, b) an inductor, c) a capacitor, d) a resistor and inductor, e) a resistor and capacitor, f) a single- phase motor (See Figure 6).
FIGURE 6 2. Calculate the real and reactive power delivered by the single-phase source in the two single-phase circuits shown in Figure 7.
FIGURE 7
3. A three-phase source having a line-to-line voltage of 69 kV supplies a starconnected resistive load having an impedance of 100 Ω per phase. Calculate the real power delivered.
4. Explain what is meant by the statement than an inductor absorbs reactive power while a capacitor supplies reactive power.
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EXPERIMENT 4: REAL POWER AND REACTIVE POWER POWER SYSTEM 1 (ECB3153) . 5. A three-phase power line, shown schematically in Figure 8, delivers real and reactive power as given in Table 2. Calculate the real and reactive power absorbed by the line.
P1
Q1
P2
Q2
P LINE
Q LINE
kw
kvar
kw
kvar
kw
kvar
+100 +100 +100 -100
+10 +10 -10 +10
+95 +95 +95 -95
+5 -10 -25 +5 Table 2
6. A three-phase line operating at a line-to-line voltage E supplies power to a starconnected load whose impedance is Z ohms per phase. Show that the total apparent power S is given by the equation. S=
E2 Z
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