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EXPERIMENT 13
Transmission Line Performance
Short, Medium, and Long Lines
Objectives:
Getting familiarized with A, B, C, D constants, SIL, short, medium and long lines,
loadability of transmission lines, shunt and series compensation of lines. Using PowerWorld
and MATLAB to solve problems.
Using PowerWorld to solve line loading and compensation problems
Study the following example from the Glover/Sarma text:
Example 5.4 - This example discusses steady-state stability limit of transmission lines.
Example 5.8 - This example discusses effect of parallel lines and line sections on the
steady-state stability limit.
Example 5.10 - This example discusses series compensation of transmission lines.
Problem 1.
Do Problem 5.43 from Glover/Sarma text.
Problem 2.
Do Problem 5.44 from Glover/Sarma text.
Problem 3.
Do Problem 5.53 from Glover/Sarma text.
Problem 4.
Do Problem 5.65 from Glover/Sarma text.
Using MATLAB to solve line loading and compensation problems
Problem 5.
A three-phase, 765 kV, 60 Hz transposed line is composed of four ACSR, 1,431,000-cmil,
45/7 Bobolink conductors per phase with flat horizontal spacing of 14 m. The conductors
have a diameter of 3.625 cm and a GMR of 1.439 cm. The bundle spacing is 45 cm. The line
is 400 km long. Assume lossless line.
(a) Determine the line surge impedance, Zc, phase constant β, wavelength λ, the SIL, and the
ABCD constants.
(b) Determine the sending end voltage, current and complex power for the specified
receiving end quantities of 735∠0° kV, 1600 MW, 1200 MVar.
(c) Find the receiving end voltage when the line is terminated in an open circuit and is
energized with 765 kV at the sending end. Also determine the reactance and the MVar of
a three-phase shunt reactor to be installed at the receiving end in order to limit the no-load
receiving end voltage to 765 kV. Obtain the ‘voltage profile’ for the uncompensated and
the compensated line.
(d) For the line loading of part (b), determine the MVar and the capacitance of the shunt
capacitors to be installed at the receiving end to keep the receiving voltage at 735 kV
when the line is energized with 765 kV. Obtain the line performance of the compensated
line.
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(e) Obtain the line performance when the line is compensated by a series capacitor for
40% compensation with the load condition in part (b) at 735 kV.
Describe how you would use PowerWorld to do Problem 5(e)
Results obtained: Show your results for Problems 1 through 5 including graphs and relevant
printouts.
Discussion of Results: Write an analysis and discussion of the results you obtained. Include
answers to the following questions.
1.
What assumptions were made that affected your calculations?
2.
How did you verify your results with respect to reasonableness and accuracy?