Solar grid tie inverter main protection function
1. Input overvoltage protection: When the DC-side input voltage is higher than the maximum allowable DC array access voltage of the grid tie inverter, the inverter is not allowed to start or stop within 0.1s (in operation) and a warning signal is released at the same time. After the DC-side voltage is restored to the allowable working range of the inverter, the inverter should be started and operated normally.
2. Input overcurrent protection: After the PV modules are connected in series and in parallel, each string is connected to the DC-side of the PV solar inverter. After the MPPT interference, when the input current is higher than the allowable DC maximum input current set by the inverter, the inverter (in operation) stops MPPT interference and sends a warning signal. After the DC-side current returns to the operating range allowed by the solar inverter, the inverter should be able to start and operate normally.
3. Output overcurrent protection: Overcurrent protection should be set on the AC output side of the grid-tied inverter. When a short circuit is detected on the grid side, the grid-tied inverter should stop supplying power to the grid within 0.1 s and send a warning signal. After eliminating the fault, the grid-tied inverter should work normally.
4. Output short-circuit protection: In case of the on grid inverter output short circuit, they must be short-circuit protective measures. The short-circuit protection action time of the inverter should not exceed 0.5s. After the short-circuit fault is removed, the equipment should work normally.
5. AC / DC surge protection: The solar on grid inverter should have lightning-prevention protection function, and the technical index of the lightning protection device should ensure to absorb the expected impact energy.