Capacitor Bank

Well maybe you should first use less undefined acronyms, DILLIGAF. Second do you remember that when current leads voltage you're providing power to the grid instead of drawing power from the grid, of course you don't. So where ever your instrumentation and protection circuitry resides, I seriously doubt that there is no over voltage condition ever happening. For when the motors get released from the grid by this relay opening I can guarantee that some very high voltages exist from the motor/generator momentarily after the relay opens.

(Good grief, I must be feeling really snarky today. Good thing I'm venting here. )