An Off Grid system on a small resort with DC Coupled MPPTS @48V Nominal. Quattro 15KVA inverter. Set to 240VAC
Several times over the last month the client has noted flickering lights and can hear the inverter with a high pitch rattling unhealthy sounding noise. Lasting approx 10minutes.
On the portal it is noted the voltage is rising and unstable reaching 259VAC and 197VAC. Load is relatively normal at around 50% (4- 4.5KW) during the evenings.
Some output Circuits/Loads are then switched off and then restored again and the system settles back to normal.
Any suggestions would be appreciated on a cause.