Power Systems T...

A power system network is having 300 buses out of which there are 20 generator bus, 10 reactive power support and 15 shunt capacitor buses. The load flow studies are conducted using Newton Raphson method. The size of the Jacobian matrix is

A 3-phase, 11 kV, 50 Hz, 200 kW load has a power factor of 0.8 lag. A delta connected 3-phase capacitor is used to improve the power factor to unity. The capacitance per-phase of the capacitor in micro-farads is

A 3-phase, 11 kV transmission line delivers a load of 2395 kVA at 0.8 power factor lag over a distance of 25 km. The transmission line has an impedance per phase of (3.25 + j 7.55) ohms. The sending end power factor is

A 20 MVA, 6.6 kV 3phase generator with X^’’_d = 10%, X^’_d = 20% and X_d = 100% is connected through a circuit breaker to a transformer. It is operating on load when a short circuit occurs between breaker and transformer.

An 11 kV, 25 MVA, 3-phase Y-connected alternator was subjected to three different types of fault at its terminals. The fault currents were:

5610 A for a three phase fault

6760 A for line to line fault

8630 A for single line to ground fault.

In a 230 kV system, the line to ground capacitance is .03 μF and inductance is 12 mH. If an instantaneous magnetizing current of 8A is interrupted find the output voltage appearing across the pole of a C.B.