Two AC generators of the same capacity are operating in parallel. One with a zero speed droop setting and the other with a 5% speed droop. If its capacity is not exceeded, what will be the characteristic of the unit whose governor has the zero speed droop setting?

Correct Answer: Option D — it will maintain the frequency of the system

An alternator governed with zero speed droop (isochronous operation) maintains a constant system frequency regardless of load variations, assuming its capacity is not exceeded. It absorbs all load fluctuations to keep the system frequency locked, while droop-governed units share subsequent load changes.