How do you test fault ride through capability?

[ccdubs]

Hi all,

I am in the situation where we are wanting to determine the fault ride through capability of our synchronous generator. I know that these things can be modelled using the inertia of the generator, AVR charecteristics, etc. But how would you go about testing this in the field?

Do you have to simulate faults by shorting to earth through some variable impedence? Or is it sufficient to just disconnect the generator and monitor the phase alignment?

Or is there another way?

Many thanks for any help.

 

[alehman]

What type of generator is this? Turbo-generator? Small diesel?

Besides normal protective relaying commissioning, one of the key items to test is the generator unloading behavior. When a fault occurs, the generator may be relieved of a significant portion of it's load. The speed control and AVR must respond quickly and appropriately. I couldn't recommend deliberately faulting the generator.

 

[ccdubs]

The generator is a 670kVA generator designed for a diesel genset.

What is "normal protective relay commissioning"?

 

[alehman]

Protection functions on a generator this size might include overcurrent, over kW, reverse power, over/under voltage, over/under frequency, overspeed, overtemp, field overcurrent and loss of excitation.

Normal genset testing would include some or all of the above along with prime mover protection functions, steady state voltage and frequency performance at various loads, block load and unload performance, and sustained full load.

As you say, fault performance depends on the speed control, AVR, excitation system, prime mover and throttle actuator. The AVR may include field forcing to sustain output during faults.