Question

Question 1: Consider a 3 phase hydropower generator feeding power into the grid bus, which is held at line voltage of 26kV. The internal reactance is 0.8pu for a rated power of 30MVA. (a) Choose as base value So.3-30MVA and Vo.Lu-26k V and calculate the per-unit (b) Assume the generator initially runs overexcited with E-1.3 pu and a real power values for the power and grid voltage output of Pe 0.32pu. Compute the reactive power and the apparent power output of the generator as measured at the grid bus. For the case in (b) find the power factor Assume the steam valve is opened to generate a 5090 increase in power Pe, what are the new power angle, the reactive power, and the new power factor? What can be done to bring back the power factor to the previous value? Explain. (c) (d) (e) () Assume that from the original initial state we increase the field current such that the armature voltage amplitude is increased by 15%, what will be the resulting reactive power? What will be the resulting power factor?

Answer 1

S. atal S hasa Aicd -ㄧㄧㄧㄧ-piu- リ こ 26 2 6 gra 30 8 PU 0 Xs

by O 312 VAR 、68

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