Download EXP4: Tie Line Scheduling

Power SystemOperation and Control (EET 415)
Laboratory Module
EXPERIMENT 4
TIE LINE SCHEDULING
1. OBJECTIVE:
To analyze the variation of frequency due to load and generation mismatch.
.
2. EQUIPMENT:
MiPower software
3. INTRODUCTION:
Almost all generating companies have tie-line interconnections to neighboring utilities.
Tie-line allow the sharing of generation resources in emergencies and economies of
power production under normal conditions of operation. For the purpose of controlling
the entire interconnected system, the system will be divided into control areas. which
usually conform to the boundaries of one or more companies. The net interchange of
power over the tie lines is the algebraic difference between area generation and area
load. A schedule is prearranged with neighboring areas for such tie-line flows, so as
long as a area maintains the interchange power on schedule, it is evidently fulfilling its
primary responsibility to absorb its own load changes. But since each area shares in
the benefits of interconnected operation, it is expected also to share the responsibility
to maintain system frequency.
Frequency dependant load flows is done to find the variation of frequency due to load
and generation mismatch. The types of FDLA are
a) Flat Tie-Line Control.
b) Flat Frequency Control.
In Flat Tie-Line Control, the power generation is kept constant and a slight variation of
frequency is allowed. If the load is capered more to the generation, there will be
reduction and vice versa.
In Flat Frequency control, the frequency is kept constant and variation of power is
allowed. Each generator is given a participation factor, which decides the power it
shares when there is mismatch between load and generation due to frequency being
kept constant.
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Power SystemOperation and Control (EET 415)
Laboratory Module
4. PROCEDURE
FIGURE 1
Figure 1 shows a 5-bus power system network of an Electric Utility Company. The
generation schedule, load data, and transmission line impedance are given in Table 1, 2,
3 respectively. The line impedance is given on 100 MVA base. Bus 1 is selected as
slack bus. Conduct Frequency Dependant Load Flow Analysis for
a) Flat Tie-Line Control
b) Flat Frequency Control
Note:
De-Rated MVA for all transmission line is 100MVA. Assume the base voltage for the bus
as 220kV and system frequency as 50 Hz.
PLEASE UNCHECKED THE LIBRARIES DIALOG BOX AFTER YOU HAVE
CONFIGURE THE DATABASE.
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Power SystemOperation and Control (EET 415)
Laboratory Module
GENERATION DATA
Bus
Voltage
No
Magnitude
DeRated
MVA
MW
Gen/Schedule
Mvar
Min
Max
Min
Max
Power
1
1.06
100
80
0
80
0
60
2
1.0
50
40
0
40
30
30
Table 1.0
LOAD DATA
Bus
Load
No
MW
Mvar
2
20
10
3
45
15
4
40
5
5
60
10
Table 2.0
LINE DATA
From Bus i to Bus j
R
X
B/2
1-2
0.02
0.06
0.03
1-3
0.08
0.24
0.025
2-3
0.06
0.18
0.02
2-4
0.06
0.18
0.02
2-5
0.04
0.12
0.015
3-4
0.01
0.03
0.01
4-5
0.08
0.24
0.025
Table 3.0
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Power SystemOperation and Control (EET 415)
Laboratory Module
Bus No and Area designated
Bus No
Area
Bus 1,3 and 4
1
Bus 2 and 5
2
1. Open Power System Network Editor.
2. Refer to the user manual provided to you for the procedure to draw all relevant
and necessary elements and inputting database configuration for the system.
3. After finish editing, run the load flow program. Select fast De-Coupled technique
and set P and Q tolerances at 0.01.
4.
Print out the Single line diagram with all revelant data. Also print out the output
data.
5. From the printed result, observed the MW generation for Generator 1. This will
be your Generation schedule and Pmax for the Gen 1when you conduct the
Frequency Dependant Load Flow analysis.
6. What is the frequency of the system and the MW generation for Area1 and Area
2?
Procedure to conduct Frequency Dependant Load Flow (Flat Tie-Line
Control).
7. Use the obtained MW generation at Gen 1 from the initial load flow information
as schedule power and Pmax for Gen 1.
8.
Change the load data of Bus 2 from 20 MW to 30MW
9.
Conduct load flow analysis once again, select Frequency Dependant Concept
LFA option on load flow analysis screen. Also select Flat Tie Line Control on
FDLC options. And maximum generation bus on Slack Bus option.
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Power SystemOperation and Control (EET 415)
Laboratory Module
10.
After execution, print out the data and the single line diagram.
11.
What is the system new frequency?
12.
Then Change the Load data at Bus 2 from 30MW to 15MW. Conduct load flow
analysis as per procedure 9.What is yr observations from the results obtain?
Procedure to conduct Frequency Dependant Load Flow (Flat Frequency
Control).
13.
Change Back the load at Bus 2 to 20 MW
14.
Change Real power maximum of Gen 1 to 150MW and Pmax for Gen 2 to 60MW.
15.
Also input the participation factor for Gen 1 at 25% and Gen 2 at 75%.
16.
Follow procedure no 3 to 4. On Load Flow Type option, select Frequency .
dependant Concept LFA. Also select Flat Frequency Control on FDLC option.
Select 0(max generation bus) for Slack Bus option.
17. Execute the program. What is the total MW generation for area 1 and area 2?
18. Now, increase the Load data at Bus 2 from 20 MW to 30Mw. Execute the program
again. What is total MW generation for area 1 and 2 and Total area interchange
error of MW generation for the system?
19. Now change the participation factor as per Table below. Conduct FDLF for Flat
Frequency Control again for each case.
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Power SystemOperation and Control (EET 415)
Laboratory Module
Participation Factor
Gen 1
Gen 2
Case 2
50
50
Case 3
75
25
20. For each case what is the total generation for Area 1 and 2? Also what is the area
MW interchange error for the system?
21. What is your observation from the result obtained?
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Power SystemOperation and Control (EET 415)
Laboratory Module
PART B: QUESTIONS
1. Three generating units operating in parallel at 60 Hz have ratings of 300,500, 600
MW and have speed droop characteristic of 5, 4 and 3% respectively. Due to a
change in load, an increased in system frequency of 0.3Hz is experience before
any supplementary control action occurs. Determine the amount of change in
system load and the mount o the change in generation of each unit to absorb the
load.
2. Two system areas connected by a tie line with the following characteristics
Area 1
Area 2
Speed Regulation R
0.01 pu
0.02 pu
Percent Change in Load for a
0.8 pu
1.0pu
500MVA
500MVA
change in Freq,D
Base MVA
A load change of 100MW (0.2pu) occurs in area 1. What is the new steady state
frequency and what is the change in tie flow? Nominal frequency for the system
is 50 Hz.
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Power SystemOperation and Control (EET 415)
Laboratory Module
DISCUSSION
CONCLUSION
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