1. A 50 Hz, three-phase, 275 kV, 400 km transmission line has the following
parameters (per phase):
* Resistance: 0.035 Ω/km
* Inductance: 1 mH/km
* Capacitance: 0.01 mF/km
If the line is supplied at 275 kV, determine the MVA rating of a shunt reactor having
negligible losses that would be required to maintain 275 kV at the receiving end
when the line is delivering no load. Use the nominal-π method.
2. A 275 KV, three phase transmission line, has the following parameters:
A=0.85 < 5˚, B= 200 < 75˚,
A. Determine the power at unity factor that can be received if the voltage profile
at each end is to be maintained at 275 KV.
B. What type of rating of compensation equipment would be required if the load
is 150 MW at unity power factor with the same voltage profile as in part (A).
3. Figure 1 shows the one-line diagram of a four-bus system. Table 1 gives
the line impedances identified by the buses on which these terminate. The shunt
admittance at all the buses is assumed to be negligible.
Figure 1: Sample system for question 3
Table 1:
Line, Bus to bus
R (per unit) X (per unit)
1–2
0.05
0.15
1–3
0.10
0.30
2–3
0.15
0.45
2–4
0.10
0.30
3–4
0.05
0.15
A. Find YBus, assuming that the line shown dotted is not connected.
B. What modifications need to be carried out in YBus if the
line shown dotted is connected.