Our turbine has a permanent magnet synchronous generator and full converter system (rectifier diods for rectification and IGBTs for chopping dc link voltage and as inverters) which means its generator doesnt need excitation current to start. Then why does it draw reactive power whenever turbine is in stop mode due to no wind or if it is manually stopped? What is purpose of this reactive power? I have been searching for this for over a month now but could not find any answer.
The converter system should have provisions to provide reactive volt-amperes to inductive loads supplied by the generator. If the converter remains connected to an active grid when the generator is shut down, it may continue to supply reactive VA to those loads. Capacitors in the converter would be supplying VA to inductive loads, not drawing reactive power from the grid.