Grid Fault message recurring

[pozzy]

My system is 14 months old and I have recurring "grid fault" messages reported on the inverter, a Solax X1-3.6-T. Installers said it was a problem with the voltage into the house, not so, now say it is to do with electricity cycles (?) and have not supplied any further help. I feel I am not getting a full benefit as this happens so often during the sunniest days when it should be generating continuously? In one instance it recurred numerous times within an hour of watching it, going through a pattern of reporting grid fault, then through the process of re-starting and almost immediately reporting grid fault again. I am no electrician , in layman's terms am I worrying unnecessarily ? It has been like this since installation..

 

[Sharpend]

This could be a poor connection on the supply from the Consumer unit possibly. Maybe they have not got the busbar located correctly?

 

[Barx]

Are you sure it just says 'grid fault'?
According to the manual, there isn't such a fault message. You have:
Grid Lost Fault
Grid Volt Fault
Grid Freq Fault

Wouldn't be the first time I have seen inverters crap out due the grid voltage being too high. If there is a load of PV systems installed locally, they can raise the voltage of the grid, all fighting to feed back. Would make sense with it happening during good production times too.
Also, as above, could be a poor connection that is breaking / making. This too could be more prevalent during good production as the current flowing will be high and more likely to warm the joint up.

If it is a bad connection (Grid Lost). My money is on either breaker not connected to bus bar properly, or loose terminal in one of the AC Isolators.

 

[binky]

Is the cable run long? In which case it can be too high a resistance causing a higher voltage at the inverter. Grid voltages can also float high due to faulty transformers, so maybe worth contacting DNO to check the grid.

 

[pozzy]

Are you sure it just says 'grid fault'?
According to the manual, there isn't such a fault message. You have:
Grid Lost Fault
Grid Volt Fault
Grid Freq Fault

Wouldn't be the first time I have seen inverters crap out due the grid voltage being too high. If there is a load of PV systems installed locally, they can raise the voltage of the grid, all fighting to feed back. Would make sense with it happening during good production times too.
Also, as above, could be a poor connection that is breaking / making. This too could be more prevalent during good production as the current flowing will be high and more likely to warm the joint up.

If it is a bad connection (Grid Lost). My money is on either breaker not connected to bus bar properly, or loose terminal in one of the AC Isolators.

yes you are correct Grid Volt Fault is the message, not many systems near us, I have checked voltage it is 240/ 250volts normally not seen it higher.

 

[pozzy]

Is the cable run long? In which case it can be too high a resistance causing a higher voltage at the inverter. Grid voltages can also float high due to faulty transformers, so maybe worth contacting DNO to check the grid.

i think my next move is to find someone to check the connections are correct?

 

[Barx]

yes you are correct Grid Volt Fault is the message, not many systems near us, I have checked voltage it is 240/ 250volts normally not seen it higher.

just for perspective. 253v is 'too high'.


Edit: I'm just trying to remember what most inverters are set to. It's been a while since I've done any PV. Think it's something like 262.2v for the stage 1 over volt trip. Be worth looking at what the inverter reads the voltage as on a good sunny day. the inverter won't necessarily read the same as a multimeter.

 

[binky]

just for perspective. 253v is 'too high'.


Edit: I'm just trying to remember what most inverters are set to. It's been a while since I've done any PV. Think it's something like 262.2v for the stage 1 over volt trip. Be worth looking at what the inverter reads the voltage as on a good sunny day. the inverter won't necessarily read the same as a multimeter.

It's certainly around 260/263V, varies by manufacturer of course, Fronius used to get upset around 256v.

 

[pozzy]

just for perspective. 253v is 'too high'.


Edit: I'm just trying to remember what most inverters are set to. It's been a while since I've done any PV. Think it's something like 262.2v for the stage 1 over volt trip. Be worth looking at what the inverter reads the voltage as on a good sunny day. the inverter won't necessarily read the same as a multimeter.

Have discovered that our supply hits 251/2v, would a voltage optimizer be the answer ? I am looking at my multimeter, couldn't find a reading on the inverter.

 

[binky]

Have discovered that our supply hits 251/2v, would a voltage optimizer be the answer ? I am looking at my multimeter, couldn't find a reading on the inverter.

coplain to DNO, request they monitor your supply for a week of so, sounds like a duff local transformer - solar is good at finding those!

 

[Sinewaved]

To find the grid voltage,long press the up arrow to get to status long press again and the tap the arrow until you get to grid voltage. The wifi dongle is worth having as all the info is saved and can be checked from anywhere.

 

[Barx]

Have discovered that our supply hits 251/2v, would a voltage optimizer be the answer ? I am looking at my multimeter, couldn't find a reading on the inverter.

Also bear in mind that if your multimeter is not True RMS, the actual voltage could be higher still, especially given that the output from the inverter isn't likely to represent a true sine wave.
If the sine wave is a little choppy, a non True RMS meter can read lower.

 

[pozzy]

I have now had confirmation form our DNO that we are being supplied with over 253 volts at times. I am waiting for the response to this. Could anyone tell me the difference between a voltage optimizer and a (cheaper) step down transformer ? Having spent several hours checking my inverter I saw dropping out 32 times in five hours, all messaged grid volt fault.

 

[binky]

I have now had confirmation form our DNO that we are being supplied with over 253 volts at times. I am waiting for the response to this. Could anyone tell me the difference between a voltage optimizer and a (cheaper) step down transformer ? Having spent several hours checking my inverter I saw dropping out 32 times in five hours, all messaged grid volt fault.

don't waste money on VO, get DNO to drop their voltages, which they can do at the local substation / transformer.