DIY Home Improvement Forum banner

Solar system with high voltage

1K views 11 replies 4 participants last post by  jim.grove1 
#1 ·
I have a SMA solar system with 3 inverters 18.3 kva. I have problem with high voltage at the house meter. The solar system has a separate meter but goes through the same transformer. The problem appears to be that in order for the solar inverters to push power to the grid they raise the voltage. Since they now see the raised voltage the raise it again. I am getting voltages as high as 160 volts at the house meter which is about 20 volts too high for things like heat pumps. Any suggestions.
 
#3 · (Edited)
Something is wrong. It really shouldn't be possible to raise the service voltage that much. The inverters should be able to push power to the utility grid without significantly raising the voltage. The high voltage rise implies that the utility service has high impedance - much higher than it should be. I think an electrician needs to evaluate this and determine if the problem is on the utility side of the meters or the customer side.

Is this a really small transformer, perhaps?
 
  • Like
Reactions: FrodoOne
#11 · (Edited)
Go outside and look at your transformer can. Most have a fairly large number on it. For residential service you should see either 10; 15; or 25. Are you the only residence connected to the transformer?

If you are trying to push 18kW through a 10 or 15 kVa transformer you may be seeing these problems. But more likely you have a high resistance connection somewhere or some other downstream problem.

A neighbor could be sending some high voltage tweaks down the line too. Are there many other solar systems nearby?

I would ask the POCO to install a voltage monitor for a few weeks.....that could help diagnose. They should be willing to that before messing around with the service.
 
#6 ·
I have had an electrician look at the system. They say everything is OK on the solar side.
When the solar system is not operating the line voltages are running 124 to 125 volts. I have been trying to get the utility to lower them, but so far no luck. The problem is worse during peak solar production. I was wondering if I could get the utility company to put the solar meter on a different transformer. Don't know if they would be willing to do that.
 
#12 ·
Unfortunately my transformer does not have a sticker on it. It is servicing two homes. I will request the electric company put a voltage monitor on my line. How can I test for resistance in the system? I have no voltage drop between the inverters and the solar meter. I have used in infrared thermometer to check connection and did not find any that were hot.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top