Power Generation: Product Operation and Maintenance

[Sohail]

Dear All,

I have 03 nos of G3520C and since few days we faced frequent tripping due to earth protection fault on our Genset # 3. We replaced its CTs cables from Genset Engine to Terberg but still facing the same problem.

Kindly advice.

Sohail

[Ahmad87]

Waht is the setpoint of earth fault tripping? How many load is ruuning on genset?

Regards

[Piet]

Checked for an earthfault allready? And does it occur when starting up or just random?

[ngobeh]

Well in such situation you have to know the grounding system that is the tpye of soil which you are using for grounding and the type of cable for the grounding and also the output of the Genset.

thanks

Jusu Ngobeh

Electo Mechanical Engineer

Freetown

Sierra Leone

West Africa

[HSJXSC]

May be you of the three-phase load imbalance

[danteoman]

Yes, all of the above are possible causes. Or recalculate setpoint.

[KenElec]

When reading your description, it appears you have 3 generators parallelled together. What is the slot pitch of each of the generators. If they are dissimilar, you may have an issue with circulating harmonic currents in the neutral leg. This happened on our training units and the result was a breaker trip due to ground fault.

[see-deif]

What is the configuration? All grounded-Star connected? 3P4W systems? Are there isolation transformers in the circuit? ONLY #3 genset trips? If you have CT's available, connect 3 phases and Neutral (if used) in parallel (WATCH POLARITIES!!) and run them to 1 meter/relay. Maybe there is a problem in that generator? Pitch could be the problem, if they have never run in parallel before.

You guys really need to put more information in your questions:  1 line diagrams, stuff like that into your questions. I am willing to help, but you are telling me only part of the story. That is like taking your car to the mechanic and saying "it's not right."

I will close with the same recommendation as to many others: you need a Power System Study. With out that, you are only guessing.

good luck

Steve