Problem:
A 500 kV, 150 MVA three-phase transmission line will use ACSR conductors. The line is 75 miles long, and the conductors are arranged in an equilateral triangle formation with sides of 9 ft. Nominal operating temperature is 50 °C.
Write a script that can determine the following parameters:
a. Per phase, find the AC resistance per 1000 ft and the total resistance of the line.
b. Per phase, find the inductive reactance per 1000 ft and the total inductive reactance of the line.
c. Per phase, find the capacitive admittance per 1000 ft and the total capacitive admittance.
d. Calculate the ABCD matrix coefficients using both the medium and long transmission line models
Demonstrate your script by showing voltage regulation and efficiency under rated load for three ACRS conductors appropriate for this particular transmission line. Compare the results from the medium and long models.
Consider the Power World model.
- Relieve the overload conditions within the transmission line and transformers by providing reactive compensation.
- Determine how much capacity can be opened up on the transmission line by providing this compensation.
- Turn in a new one-line showing the flow of both real and reactive power. Comment on the new reactive power flows.
Problem:
Expand your power system simulation from Homework #2 by replacing the 13.2kV transmission line with a 138kV line. Correspondingly, transformers are now required at the load and generator'. System specifications:
- 13.2kV load bus
o Load 1: 530kVA, PF = 0.91 lagging
o Load 2: 420kVA, PF = 0.80 lagging
- Transmission line:
o 0.80/vIVA capacity
o R = 0.02Q/mile, X = 0.252/mile
o d = 80 miles
o 138kV
- 24.2kV generator bus; set as 'system slack bus'
o Generator: 0.9MW, OMVAR (these will change when the simulation runs)
- Transformers
o 24.2kV-138kV step-up (generator)
o 138kV-13.2kV step-down (load)
o 800kVA rating
o Series resistance, 0.01pu3
o Series reactance, 0.03pu
o Shunt Charging, -0.001pu (13 = 1/jX. from Chapman, in per-unit form)
o Shunt Conductance, 0.0005pu (G = 1/Ik from Chapman, in per-unit form)
Run a "Single-Solution Full Newton" simulation. Turn in a printout of your simulated power system circuit.
Determine the percentage of the transmission line and transformer MVA rating used by the system.
Calculate the generator-to-load real power transmission efficiency. Are system components, transmission line and transformers, properly sized?