Generator rotor insulation resistance
Generator rotor insulation resistance
(OP)
On a 200MW generator, the rotor insulation resistance displayed on REG316*4(with REX 010 and 011) is variable in operation,between 4 and 30kohm.
The rotor insulation resistance measured with rotor not in rotation is very good.
The rotor and the relay were checked and seem to be ok.
The problem appeared from rehabilitation of the unit, when the protection and control system was replaced with a digital one.
Does anyone encountered such a problem?
The rotor insulation resistance measured with rotor not in rotation is very good.
The rotor and the relay were checked and seem to be ok.
The problem appeared from rehabilitation of the unit, when the protection and control system was replaced with a digital one.
Does anyone encountered such a problem?






RE: Generator rotor insulation resistance
If you check the opn of the new REG using a resistance decade box (unit at standstill) do you get correct operation ?
What are the Mohm readings of the rotor at standstill?
I am not familiar with that particular relay, but would imagine it must have a filter to remove the ripple from the static exciter built in, if that is what you have.
rasevskii
RE: Generator rotor insulation resistance
Looking at your numbers I'm guessing that you are running sometimes in alarm
RE: Generator rotor insulation resistance
Please attach a wiring diagram of REG316 and REX( what type), and capacitors (2 or 4mF ?).
Do you provide commissioning according to commissioning procedure.
Please attach graph of test.
Usually problem with wiring, check connection of cpacitors, check capacitors.
Check connection of grounding wire.
Possible some real problem and you have some temprary contact between plus or minus with grounding.
RE: Generator rotor insulation resistance
Also try changing the bridge supply phases. For example if it's supplied by A and B, try A and C or B and C. Not sure why this works but it's recommended in the manual and I've had some success with it.