Hello, I have an ESS system based on Cerbo GX, Multiplus 2 48/5000/70 230Vac and additional PV invertor Fronius Primo 5.0.1 (conencted to the AC OUT of the Multiplus). The batteries are 2x3.5KWh Pylontech. The excess energy is fed back to the grid. The ESS installation is located in a village, where there are no high loads around. In some periods of time , the neigbors are consumimng more energy and my ESS installation is able to feed them with the excessive energy from the PV panels. However, in other periods of time there is no enough consumption and my ESS system (when it is sunny) starts increasing gradually the grid voltage trying to “inject” the excess energy to the grid. At certain moment the maximum grid voltage is reached and the Multiplus II disconnects from the grid. At that moment the grid voltage “normizlizes” (to about 240Vac) and the Multiplus connects again to the grid after some delay. Again it starts gradually increasing the voltage until the maximum voltage level is exceeded and disconects again.
I wonded, is there a way to configure the ESS system to regulate/reduce MPPTs and PV invertor so the received PV energy not to lead to increasing the grid voltage over the limit (thus to reduce the number of disconnections to the grid)?
My PV panels are conencted to the MUltiplus II via MPPTs and the PV invertor are generating up to 9kW that should be fed up to the grid (to one of the phases of the grid - my ESS is single phase). How this power can be transfered to the grid?
The house is in a village, apparently the grid is not so low ohmic, there are several other neighbours that consume power nearby but the consumption is not constant. So in some days, I can see on the VRM portal readings that the AC IN voltage of the Multipus II starts increasing together with the power fed up to the grid. When the higher limit of the grid voltage is reached, the Multiplus disconnects and at that moment I can see AC IN drops synchronously with the disconnection.
So I pretty sure that the gradually increased voltage is coming from the Multiplus which is trying to “inject” the PV energy to the grid…
Unless you get paid for feeding in, consider not feeding in. In Aus lower daytime consumption with over PV production can be managed by grid operators who can disable the feedin of households remotely when grid voltages get too high.