Relay protection

Dear Sir/Madam,

I would like to ask you about my problem in our power plant,
exactly about protection relay coordination.

Case : When any disturbance at our grid,
power plant almost always going into black out condition.

as I know, if we have disturbance at grid,
power plant should not trip or black out and we operation use house load condition.

My question :
what should I do, that if any disturbance at grid our power plant still in house load condition?