PV Inverter - Voltage Rise on One Phase
PV Inverter - Voltage Rise on One Phase
(OP)
I'm troubleshooting a PV installation where we have 10 3Ø inverters tied into a single switchboard then running a few hundred feet to the point of interconnection at a dedicated pad mount transformer.
When the PV panel main breaker is off, all voltages are nominal L-G 277V range. When the inverters connect and begin to export, the voltage on phase B & C go up to 280 or so and voltage on Phase A keeps rising up until the inverter shuts off due to overvoltage (around 305V)
I know that voltage rise is to be expected (and conductors were upsized to account for this, the 280V values are in the anticipated range.
But what I cannot figure is the voltage rise on Phase A. My thoughts are that it has to be a cable fault, transformer issue, faulty fuse-link etc. Anything else would effect all 3 phases equally. Right?
When the PV panel main breaker is off, all voltages are nominal L-G 277V range. When the inverters connect and begin to export, the voltage on phase B & C go up to 280 or so and voltage on Phase A keeps rising up until the inverter shuts off due to overvoltage (around 305V)
I know that voltage rise is to be expected (and conductors were upsized to account for this, the 280V values are in the anticipated range.
But what I cannot figure is the voltage rise on Phase A. My thoughts are that it has to be a cable fault, transformer issue, faulty fuse-link etc. Anything else would effect all 3 phases equally. Right?






RE: PV Inverter - Voltage Rise on One Phase
Keith Cress
kcress - http://www.flaminsystems.com
RE: PV Inverter - Voltage Rise on One Phase
RE: PV Inverter - Voltage Rise on One Phase
I had a similar case a few months back where one of the medium voltage fuses was partially blown. I could measure normal voltage with all equipment off, but when I turned on an inverter B phase voltage rose rapidly. When I plugged in a shop vac, B Phase voltage dropped rapidly.
-JFPE