A synchronous machine:

Question

Question

This question was previously asked in

MPPGCL JE Electrical 19 March 2019 Shift 2 Official Paper

Answer 1

Flow of Reactive Power in Synchronous Machine

A synchronous machine can operate either as a generator or a motor, and its reactive power behavior depends on its excitation level:

Overexcited Synchronous Machine:

When a synchronous generator is overexcited, it behaves like a capacitor and delivers lagging reactive power (i.e., it supplies reactive power to the system).
This means it delivers positive VARs (Volt-Ampere Reactive) to the grid.

Hence, option 1 is correct.

Underexcited Synchronous Machine:

When a synchronous generator is underexcited, it behaves like an inductor and draws reactive power from the system.
It absorbs lagging reactive power (i.e., takes in reactive power from the grid).

Hence, option 4 can also be correct.