GATE 2022 EE : Power System Quiz 80

A 3 phase, 50 Hz synchronous Generator is connected to an infinite bus through a transformer and two parallel transmission lines. Grid is consuming a power of 0.8 + j0.4 P.u. Generator reactance is 0.25 P.u., transformer reactance is 0.5 P.u., and each transmission line reactance is 0.5 P.u., and each transmission line reactance is 0.5 P.u. If the infinite bus voltage is 1∠0 P.u., then what is the Generator voltage load angle and Generated emf.

A generating station has an overall efficiency of 15 % and 0.75 kg of coal is burnt per kWh by the station, The calorific value of coal in kcal/kg.

Three generators are feeding a load of 100 MW. The details of the generators are

In the event of increased load power demand, which of the following will happen?

A 3ϕ alternator with grounded neutral has a reactance of 3Ω. It is connected to bus bar through a circuit breaker. The capacitance of the circuit between circuit breaker and the alternator is 0.001 μF per phase. If a short circuit occurs on bus bar and the breaker opens with RMS value of current 6KA, then the maximum RRRV (in) is (operating frequency is 50 Hz).

A 100 MVA synchronous generator operates on full load at a frequency of 50 Hz. The load is suddenly reduced to 50 MW. Due to time lag in governor system, the steam valve begins to close after 0.4 second. The change in frequency that occurs in this time will be
[H = 5 kW-s/KVA of generator capacity]