Question

A three-phase 55 Hz, 500 MVAR, 11.8-kV, 6 pole steam turbine generating unit has an H constant of 5 p.u. Determine a) synchronous mechanical and electrical angular frequencies, b) Consider the damping is ignored and the initial rotor angular position is 30 degrees. Find the electrical and mechanical rotor angular position in radians after three cycles if the mechanical power is 1 p.u. and the generator rotates at synchronous speed. C) The unit is operating at Pm=1 and the synchronous speed with initial rotor angular position of 10 degrees. A three-phase to ground fault happens at t=0, assume the operator increases the mechanical input power by 20 % after the fault, find the power angle after 5 cycles.

Answer 1