Neutral Earthing for 11kV system
Neutral Earthing for 11kV system
(OP)
Dear Folks,
In one of the Power plant projects, 11kV system is used with solid grounding. Now Black start diesel generator needs to be connected to the same system as stand-by. Both systems need to be operated in parallel during change-over operation. In this case, we would like to use low impedance grounding to new stand-by diesel generator neutral. Please discuss pros and cons.
Advanced Thanks..
In one of the Power plant projects, 11kV system is used with solid grounding. Now Black start diesel generator needs to be connected to the same system as stand-by. Both systems need to be operated in parallel during change-over operation. In this case, we would like to use low impedance grounding to new stand-by diesel generator neutral. Please discuss pros and cons.
Advanced Thanks..






RE: Neutral Earthing for 11kV system
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If we learn from our mistakes I'm getting a great education!
RE: Neutral Earthing for 11kV system
RE: Neutral Earthing for 11kV system
Why not, I think, you have a right solution.
"Problem" maybe, will happened if in case of chnge-over will some ground fault. What about ground fault protection selectivity in case of operation on the stand-by diesel, w/o grid.
Best Regards.
Slava
RE: Neutral Earthing for 11kV system
Planning to use different protection groups in protection relays according to source.
RE: Neutral Earthing for 11kV system
In this case, you can change solid grounding to low impedance, it's only additional of grounding resistor and forgot about change protection group of protective relay.
Protection was "problem" and you solved it.
In any case you don't have problems.
Good Luck.
Slava
RE: Neutral Earthing for 11kV system
But the existing equipment insulation levels are designed for solid-grounding system. Is it possible to operate the existing equipment with low impedance grounding system, however Line-ground faults will be cleared in a short-time.
RE: Neutral Earthing for 11kV system
Regards
Marmite
RE: Neutral Earthing for 11kV system
Good point! In this case, all existing surge arrestors to be replaced, suitable for low impedance grounding system, however the system operates with both effectively grounding system and low impedance grounding system. Right!!!