Solaredge 66.6kW 3ph inverter wont work while 300hp pump with VFD

[Devendra Rajwade]

I would like to get some help with an issue with one of the solar systems.
This is on a farm with 300HP pump-motor connected to a VFD. 3ph - 480/277V Power from the utility transformer terminates line side at 400AMp breaker in VFD cabinet going through the utility meter cabinet. Breaker has three termination lugs on each side. Wires from two load side lugs are connected to the VFD and the the 3rd load side lug is used to terminate the solar system. Solar side consists of two 66.6kW Solaredge 3Ph-480/277V inverters, whose combined output (160A) is connected to the breaker through a fused disconnect
Here is the problem, Inverters run normally when pump is off. If inverters are producing power and then the pump is turned on they continue to run normally. If pump is running and then you start the inverters they will not produce power and go into starting loop. This scenario is usually in the morning when pump is running over night and inverters wake up in the morning as the sun rises.
Solaredge support is aware of the issue but has not provided any resolution. Any guidance in identifying the cause is appreciated.

 

[petersonra]

I would be looking at what the incoming voltages are at the times it works and the times it does not. With low load it could be the incoming voltage is higher causing the invertors to stay off.

 

[Devendra Rajwade]

Thanks. The L-L voltages when inverters are running along with the pump are 465V. And L-L voltages when Inverters are running but Pump is not running is 492V

 

[hillbilly1]

I would be looking at what the incoming voltages are at the times it works and the times it does not. With low load it could be the incoming voltage is higher causing the invertors to stay off.

I think the op is saying the opposite is happening

 

[petersonra]

I think the op is saying the opposite is happening

Look at post 3

 

[petersonra]

Thanks. The L-L voltages when inverters are running along with the pump are 465V. And L-L voltages when Inverters are running but Pump is not running is 492V

Check with invertor manufacturer and see what the upper voltage cutoff is. It might be adjustable.

 

[electrofelon]

Check with invertor manufacturer and see what the upper voltage cutoff is. It might be adjustable.

But that doesn't make sense. He said the inverters are fine when the pump is off. That would be the highest voltage scenario. OP didn't say what the voltage was with pump but no inverter was, maybe it's getting too low. I would guess the standard voltage window for the inverter, unless it's been fiddled with is +/- 10%

 

[pv_n00b]

Thanks. The L-L voltages when inverters are running along with the pump are 465V. And L-L voltages when Inverters are running but Pump is not running is 492V

Voltage range for the 66.6kW is 422.5 to 529V so it's not a nominal voltage problem. Maybe the VFD is putting so much noise on the line it's causing a problem.