High grid voltage trip and limits

[denmancentral]

My grid voltage is fairly high - approx 245 V to 250 V overnight is common. On some sunny days my inverter trips on AC10M error, which is 10 minute average voltage too high. There is the option of increasing the trip limit in the inverter. I think it's currently set to about 255V.

Question is, what are the risks of doing this? Anything in the house that might not like that voltage? in any case, I'm not sure if having the inverter connected makes much difference to the house voltage as it doesn't drop much when the inverter trips. I think in theory it does raise it, though.

Anyone got experience of this?

 

[binky]

most inverters can be set to around 260V, but I've never liked he idea, it's pushing your appliances to the limits. In theory you should be seeing 253V max from the grid, but if you are having problems, it may suggest a problem with your grid supply. I had a case where the inverter kept cutting out at certain times of day. We requested the DNO to investigate, they installed some monitoring gear for a week at the house, and discovered the local transformer had a faulty 'variable tap' that was sticking slightly and pushing grid voltages too high in the evenings. So I would be inclined to talk to your local DNO and ask them to investigate - solar systems are good at finding grid faults!

 

[denmancentral]

thanks! I am holding off contacting them as they are still working on my meter export MPAN and don't want to mess that up. It's taken 2 months already!

 

[johnb2713]

Question is, what are the risks of doing this? Anything in the house that might not like that voltage? in any case, I'm not sure if having the inverter connected makes much difference to the house voltage as it doesn't drop much when the inverter trips. I think in theory it does raise it, though.

The inverter shouldn't really raise your house supply by much, what you may be seeing is the action of the inverter taking the load so the volts drop in your supply cable becomes zero as the inverter takes the load. The inverter does raise the supply voltage slightly until the import becomes zero.

 

[binky]

The inverter shouldn't really raise your house supply by much, what you may be seeing is the action of the inverter taking the load so the volts drop in your supply cable becomes zero as the inverter takes the load. The inverter does raise the supply voltage slightly until the import becomes zero.

I must get the multimeter out one day and see what voltage I'm getting within the house on the circuits. The inverter is basically supplying at the grid connection to shut the grid out, so there will be voltage drops along the cables, but I've never looked at how much.