trippnig of one generator operating in parallel

Hello Guest,

Nobody is presently able to tell you the answer, because you fail to supply several essential details of the installation.

Kind Regards....

ok

the GTG are 25 MW rated,11 kv,50hz

total load is 20MW

suddenly one gtg trips.

how thw frequency of the running GTG will vary with sudden load,

any relation with frquency and load ?

Hello again, Guest,

You have not yet advised the rotating mass, nor the rotor speed in RPM.

The brand of the unit would also be helpful, along with the nameplate details.

The reason for the brand/nameplate requirement should be obvious to you.

If those are advised, then your chances of a proper answer markedly increase, as I'm sure you must realize, if you are involved with such generation equipment.

Kind Regards....

There are number of different things that can happen, and things to consider. Are the two units part of a larger system, are they on full load, and how far away from the load are they and the type of load, capacitive or reactive, is there any spinning reserve and how long for it to come on line. There are two immediate problems, over load and excessive voltage generated by the capacitive effect of the transmission lines, either could lead to the lost of the other unit. So as you may now appreciate, more information is needed.

Regards JD.

PS.

Looking for the simple answer, and here we are assuming that the other unit is not subject to all the other possibilities, yes the frequency will drop. The reason being that when the other unit takes the load, the governer will act to system frequency, and part of the govenor control is the droop unit. This is different from the govenor set point, which one might think would return the system back to it's previous frequency? The droop is set at about 3 1/2 percent of operating speed, 105 rev's for a 3000 RPM system, it's this drop in rev's that causes the govenors to open. So I suggest you Google some info on that.

Regards JD.

If the generators are more than 50% loaded and one trips, the entire load will be placed on the other generator and it will be overloaded. Then it becomes a matter of a critical race between the circuit protection device and the energy source driving the generator as to what will happen. If the circuit protection device opens, the generator will suddenly be released.

What happens when your car tire hits a patch of ice?