Question

Q. An alternator is connected to infinite bus and supplying Sl=P1+jQ1. Assuming the governor and exciter are controlled manually, what actions should be taken by the operator in the following scenarios: (a) The alternator needs to supply S2=P2+jQ1 where P2>P1 (b) The alternator needs to supply S3=P2-jQ1.

Answer 1

a> As in this case real power is to be increased keeping reactive power constant.It means steam input must be increased so as to increase real power. This can be done by governor operation so that more steam can flow.

b> In this case both real power and reactive power should be changed. As real power is to be increased, it means steam input must be increased by governor operation. Also reactive power is changed, it means exciter must be controlled so that alternator can supply leading reactive power.