Mitigation StrategiesAnti-Islanding Protection Solar PV systems are typically equipped with anti-islanding protection devices that detect grid faults and disconnect the PV system from the grid to prevent backflow.
According to different system voltage levels, photovoltaic anti-backflow systems can be divided into single-phase anti-backflow systems, three-phase and energy storage system ones. In a power system, power is generally sent from the grid to the load, which is called forward current.
Deye inverter anti-backflow working principle: install an meter with CT or current sensor at the grid-connected point. When it detects that there is current flowing to the grid, it will feed back to the inverter, and the inverter will immediately change its working mode and track from the maximum power point of MPPT.
Upon detecting current flow towards the grid, the inverter will reduce its output power until the countercurrent is eliminated, thereby achieving anti-backflow. It is important to note that the CT and meter themselves do not have anti-backflow capabilities; they simply collect data to enable the inverter to adjust its output accordingly.
Why do photovoltaic power generation systems need anti-reverse flow equipment?
If there are many such power generating sources to transmit electricity to the power grid, the power quality of the power grid will be seriously degraded. Therefore, this type of photovoltaic power generation system must be equipped with anti-reverse flow equipment to prevent the occurrence of reverse power. How does backflow prevention work?
One of the main benefits of DC-coupling Solar and Storage is that you can charge the batteries during the day from generation that might have otherwise been clipped by the inverter and then discharge that energy in the evening when the PV is not producing.
To avoid back feed in such situations, you can set-up your SCADA system to shut down the SPOTs in the event this occurs by issuing a command directly to the SPOTs via the Modbus protocol.