Over Voltage on Grid

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Hi Group

I was alerted to an alarm on my newly installed 4kw inverter today which it shut down for a short period of time due to over grid voltage.


255.8.pngHaving a look in AS4777.3 it mentions, if I read this correctly, that inverters are not allowed play on the grid if the grid voltage is greater then 255 volts, looking at the inverters error logs seem the grid voltage went to 255.8 volts which shut production down for a short time.

I wonder will this be an ongoing issue and why does the voltage spike like this ?



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Hi Peter3991,

                       We had an over voltage issue earlier this year which was caused by lots of solar production and low consumption in our local grid.  This artificially raised the line voltage which caused our inverter and battery system to shut down until the voltage returned to tolerance.

This happened over a mild spell of weather where there was a low usage of heating or cooling.


It was solved by SAPN (SA distribution) switching us to a different phase from the mains which had less solar feed in on it.  It did the trick.

Solar inverters feed in at a higher voltage than the mains (our is set to peak at 259v I think).  If you have a lot of feed at this higher voltage and not much consumption on the phase in your local grid the voltage is pushed up.

This is my layman understanding of this.....happy to be corrected 

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Thanks Woodun

Found this article which was interesting to the discussion