Generator Ground
Generator Ground
(OP)
Hi,
I have five 13.8 KV generators each rated 1.7 MW each. It is an emegency gen system for a mining application.
Here is my question: I have experience with 600 V emergency generator systems. Here is my policy for grounding:
"In case of emegency generator installation, If emergency generator has to operate in parallel with utility, then It needs to have a seprate ground and should be also connected to utility ground other wise it does not need to have a seprate ground. I am talking about 600 V level. "
Do I need to have a seprate Low resistance grounding for these 13.8 KV generators and also connect them to utility ground.
Actually the dilemna is that: How do I decide that this generator needs to have its own grounding or only utility ground will be fine.
I apologize, if I was not able to express my self clearly.
Thanks






RE: Generator Ground
If the generators feed a distribution system that can be generator, utility, or both in parallel, you need to look at how your ground fault detection works. Lots of issues to be considered, not nearly enough information to begin to work out the details.
RE: Generator Ground
I would advise hiring competent and experienced electrical consultants for this type of project.
RE: Generator Ground
Suppose, I have a situation where it is 600 V and 1.5 MW generator with parallel operation to utility. Then I will have to resort to an independent grounding of generator which as per new Arcing phenomena will be high resistance.
Please advise me, if it is a right proposition?
The question in regard to 13.8KV and 1.7 MW genertors is a study we are working on will be installed in Africa. The local utility is 230 KV and will be stepped down to 13.8 KV.
Now, my sr. engineer has not yet decided and the client is not sure, if he wants a parallel operation or not.
So, will my this rule with low voltage work. If the generators will operate in parallel with utility then I should go for low resistance grounding as it is a 13.8 KV system. If they will always operate during emergency operation then I can just hook to the utility neutral.
I understand this might be a lengthy question to answer. I have access to all IEEE standards online. Please advise, which standard can give me a better picture.
Thanks
RE: Generator Ground
RE: Generator Ground
As rbulsara suggested, you really need to be working directly with someone familiar with these types of systems; you'll get much better results that way than you will here.
RE: Generator Ground
I completely agree with your suggestions. One last part here, which no body mentioned.
If I have to operate a 600 V gen. in parallel with utility, Do I have to for a resistance grounding or just connect generator neutral to utility neutral.
Thanks
RE: Generator Ground
Again, the answer depends on your 600V system. If you have no line-to-neutral loads, you could resistance ground to limit ground fault current. However, 480V and 600V generators are commonly solidly-grounded.
RE: Generator Ground