Download EXP2:Reactive Power Optimization

Power System Operatios and Control (EET 415)
Laboratory Module
EXPERIMENT 2
REACTIVE POWER OPTIMIZATION
1. OBJECTIVE:
To minimize a system active power loss by reactive power optimization.
2. EQUIPMENT:
MiPower software
3. INTRODUCTION
Alternating current (AC) is supplied in a 60Hz waveform. Reactive power is produced
when the current waveform is out of phase with the voltage waveform due to inductive or
capacitive loads. Current lags voltage with an inductive load, and leads voltage with a
capacitive load. Only the component of current in phase with voltage produces real or
active power that does real work. Current is in phase with voltage for a resistive load,
like an incandescent light bulb. Reactive Power is necessary for producing the electric
and magnetic fields in capacitors and inductors.
Energy losses in transmission lines and transformers are of two kinds: resistive and
reactive. The former are caused by resistive component of the load and can not be
avoided. The latter, coming from reactive component of the load, can be avoided (Fig.
1). Reactive losses come from circuit capacitance (negative), and circuit inductance
(positive). When a heavy inductive load is connected to the power grid, a large positive
reactive power component is added, thereby increasing observed power load (Fig. 1).
This increases losses due to reactive load current, increases kVA demand, increases
customer energy consumption, usually degrades voltage profiles, and reduces revenue.
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Power System Operatios and Control (EET 415)
Laboratory Module
The controllable reactive power sources include generators, shunt reactors, shunt
capacitors and On Load Tap Changers of transformers (OLTC). Generators can
generate or absorb reactive power depending on the excitation. When overexcited they
supply the reactive power, and when underexcited they absorb reactive power. The
automatic voltage regulators of generators can continually adjust the excitation [1].
Reactors, shunt capacitors and OLTC are traditionally switched on/off through circuit
breakers on command from the operator. Since the early eighties, advances in Flexible
AC Transmission Systems (FACTS) controllers in power systems have led to their
application to improve voltage profiles of power networks. The most frequently used
devices are: Reactive Power Controller(RPC) and Static Var Compensator (SVC).
4. PROCEDURES
Figure 2.1
The IEEE 6-bus system is shown in Figure 2.1. Bus 1 is the swing bus, bus 2 is a PV bus,
while Bus 3, 5 and 6 are PQ buses. The two branches with tap-setting transformer are
branch 4-3 and 6-5. The line data, Generator and transformer data and its initial state
variables for the IEEE 6-Bus system are shown in Tables 2.1, 2.2 and 2.3 respectively.
All impedance are given at 100Mva base. While the nominal voltages for all the buses are
33 kV. Find the reactive power optimization for the power system within the below
constrains.
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Power System Operatios and Control (EET 415)
Laboratory Module
Bus Voltage magnitude constrains:
0.95  V  1.05
Transformer Tap Position constrains :
0.95  T  1.05
Generator Bus Reactive Power Constrains: -20  Q  100
Bus code
Impedance
From i to j
R +jX
6-1
0.123 + j0.518
6-4
0.080 + j0.370
4-1
0.097 + j0.407
5-2
0.282 + j0.640
2-3
0.723 + j1.050
Table 2.1
Bus
No
Load
Load
MW
MVAR
1
0
0
2
0
0
3
55
25
4
0
0
5
30
20
6
50
20
Figure 2.2
Element Data
Generator 1
Generator 2
Manufacturer Ref No
1
2
No of Units Parallel
1
1
De-rated MVA
200
200
Schedule Power
100
100
Real Power Min
50
50
Real Power Max
150
200
Reactive Power Min
0
-20
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Power System Operatios and Control (EET 415)
Laboratory Module
Reactive Power Max
100
100
Specified Voltage
1.02 p.u
1.02 p.u
Table 2.3
Transformer Data
Transformer 1
Transformer 2
Reference No
1
2
MVA Rating
200
200
Tap Position
5
5
From Bus i to Bus j
4-3
6-5
Control Bus
4
6
Positive Seq Impedance
0.133
0.133
Table 2.4
1. Double click the MiPower icon on your pc screen.
2. Follow the procedure in lab manual in order to draw and input all the data
3. For transmission line, load and generation database, use the data from Table 2.1
and 2.3 respectively.
4. For Transformer database, use the data from Table 2.4.
5. After finish editing, run the load flow program. Select fast Decoupled method on
the Load Flow analysis screen.Set P and Q tolerances at 0.001. Also check the
Optimal power Flow Analysis and Q Optimization box as shown below.
6. After execute, save the report in your pc and print it out. This will be the reactive
power optimization simulation for power flow studies.
.
7. Fill in Table 1in your answer sheet. States any voltages constrain violation of the
system.
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Power System Operatios and Control (EET 415)
Laboratory Module
8. What is the total reactive power generated at Gen 2? States if any violation
occurred?
9. What is the system total active Power loss?
10. Now, install a shunt capacitor at Bus 3, 4 and 6. The details of the shunt
capacitor data are given below.
Bus No
Mvar
MVA
Rating
kV
Rating
Positive
Susceptance
3
50
100
33
0.5
4
15
100
33
0.15
5
45
100
33
0.45
11. To draw a shunt capacitor, click on
on the GUI network editor. The following
screen will popped up on the screen.
12. Click on the Shunt Capacitor Libraries data. The shunt library data will appear
as shown below.
13. Follow the same procedure to draw shunt capacitors at Bus 4 and 6.
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Power System Operatios and Control (EET 415)
Laboratory Module
14. Now, conduct lab procedure no 5 until 7 to simulate the updated data. Complete
the answer sheet as Q 8 to Q10.
15. Now, change the tap setting of OLTC of Transformer 1 and 2 to 1.05 p.u (tap9)
and 0.95 p.u (Tap1) respectively. Also change the schedule power for Gen 2
from 100 MW to 50MW.
16. Conduct lab procedure similarly as No 14
17. Plot the single line diagram with all relevant data for the experiment. Also print
out the output report for this experiment.
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Power System Operatios and Control (EET 415)
Laboratory Module
PART B.
1. Describe in your own words the meaning of Reactive Power Optimization. Elaborate
more on the importance of conducting it in terms of loss minimization and variable
constrains. Also states equipment which absorbs and generate reactive power and
its effect on the Generator performance.
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Power System Operatios and Control (EET 415)
Laboratory Module
EXP 2: Reactive Power Optimization
NAME:__________________________________ MATRIX NO __________________
EXPERIMENT NO:________________________ DATE________________________
ANSWER
9.
Parameters
Voltage Magnitude
Violation (Yes/No)
Bus 3
Bus 4
Bus 5
Bus 6
Generator 2
Reactive Power generate for 2 _____________
Total active Power Loss _______________
15.
Parameters
Voltage Magnitude
Violation (Yes/No)
Bus 3
Bus 4
Bus 5
Bus 6
Generator 2
Reactive Power generate for 2 _____________
Total active Power Loss _______________
16.
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Power System Operatios and Control (EET 415)
Parameters
Voltage Magnitude
Laboratory Module
Violation (Yes/No)
Bus 3
Bus 4
Bus 5
Bus 6
Generator 2
Reactive Power generate for 2 _____________
Total active Power Loss _______________
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Power System Operatios and Control (EET 415)
Laboratory Module
Discussion
Analyze the laboratory result. Comment on the bus voltage and total real power loss
compared with the system with and without the shunt capacitor. And a system which has
been optimized together with the use of Tap change transformer and Generator 2 MW
output.
(10 marks)
Conclusion
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( 5 marks)
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