Suppose I have two synchronous generators. One rated 10 MVA with H=4s and the other 20 MVA with H=2s.

I understand that the SIRs of the generators don’t depend on their operating point.

But if both are working at, let’s say, 5 MVA, and there’s an outage of another generator in the grid, wouldn’t the 20 MVA generator contribute instantaneously with more MVAs than the 10 MVA, even for a shorter period of time?

Can the higher MVA rating compensate for the lower inertia constant?

I’m looking forward to hearing from you.

Carlos Melim