Here is an analysis of failure reasons for photovoltaic inverter: 1) Leakage. When the leakage is too large, take out the input end of the PV array, and then check the external AC power grid. The DC and AC ends are all cut off. Let the inverter power off for 30 minutes, and continue to use it if it can be repaired. 2) Low insulation resistance. Unplug all the strings on the input side of the solar charge inverter, and then connect them one by one. Use the solar inverter to start and check the insulation resistance function, and check the problem strings. 3) No response when starting. It is very important to carefully read the inverter operation manual to ensure that the positive and negative poles are crimped again. The solar inverter is internally connected with anti-short circuit protection, which can normally start after the wiring is completely restored. 4) DC over-voltage protection. The temperature coefficient must be taken into consideration in the design to prevent the equipment from being hard-damaged due to overpressure at low temperatures.