Loads connected to AC in during external anti-islanding disconnection

Q&A and troubleshooting
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1

Hi Friends, can anyone help me with this?

I am building a grid-parrallel multiplus-2 based system, it is for the UK and therefore requires G99 anti-islanding. I am providing this by using an external Ziehl based relay, which disconnects the whole installation.

The relay is remote to the inverter, with only one set of cables linking them. I expected I could simply connect the AC supply/loads to the AC in of the multiplus, but I am now worrying that the inverter will isolate the loads which are on its AC in once the G99 relay activates, despite the fact that there will be no grid code set.

Is this the case? Will the inverter cease powering loads on its AC in once AC grid is disconnected? These are almost all the loads ! Is there a way around this if so?

Thanks in advance

James

2

Gridcode set or not doesnt matter, loads on the ACin are never powered in island condition.

The proper way would be to place the MP in place of the Ziehl relay, since the MP2s are certified to work without an external anti islanding relay.

A workaround could be to use the external tranfer switch firmware.

But in any case, you will need additional cables between the point of grid disconnection and the MPs. Question is just if its cables rated for the whole load or just voltage measurment and relay coil