Summary of common problems displayed on the inverter screen. Are you affected?

Fault analysis: There is no DC input, the inverter LCD is powered by DC.

Possible causes:

(1) The component voltage is not enough. The inverter working voltage is 100V to 500V. When it is lower than 100V, the inverter will not work. The component voltage is related to the solar irradiance.

(2) The PV input terminals are connected in reverse. The PV terminals have positive and negative poles, which must correspond to each other and cannot be connected in reverse with other groups.

(3) The DC switch is not closed.

(4) When the components are connected in series, one of the connectors is not connected properly.

(5) One component is short-circuited, causing other strings to stop working.

Solution: Use the voltage range of the meter to measure the DC input voltage of the inverter. When the voltage is normal, the total voltage is the sum of the voltages of each component. If there is no voltage, check the DC switch, terminal blocks, cable connectors, components, etc. in turn to see if they are normal. If there are multiple components, connect them separately for testing. If the inverter has been used for a period of time and no cause is found, it is the inverter hardware circuit that is faulty. You can contact the manufacturer for after-sales service.

2. The inverter is not connected to the grid, and the screen shows that the mains is not connected.

Fault phenomenon: The inverter is not connected to the grid, and the screen shows that the mains is not connected.

Fault analysis: The inverter is not connected to the grid.

Possible causes:

(1) The AC switch is not turned on.

(2) The inverter AC output terminal is not connected.

(3) During wiring, the upper row of inverter output terminals became loose.

Solution: Use the voltage range of a multimeter to measure the inverter AC output voltage. Under normal circumstances, the output terminal should have a voltage of 220V or 380V. If not, check whether the wiring terminals are loose, whether the AC switch is closed, and whether the leakage protection switch is disconnected.

3. The screen shows that the PV voltage is high

Fault analysis: DC voltage is too high alarm

Possible cause: Too many components are connected in series, causing the voltage to exceed the inverter voltage.

Solution: Due to the temperature characteristics of the components, the lower the temperature, the higher the voltage. The input voltage range of the single-phase string inverter is 100-500V, and the recommended voltage after stringing is between 350-400V. The input voltage range of the three-phase string inverter is 250-800V, and the recommended voltage after stringing is between 600-650V. In this voltage range, the inverter is more efficient and can generate electricity when the irradiance is low in the morning and evening, but the voltage will not exceed the upper limit of the inverter voltage, causing an alarm and shutdown.

4. The screen shows that the PV insulation impedance is too low

Fault analysis: The ground insulation resistance of the photovoltaic system is less than 2 megohms

Possible causes: There is a short circuit to the ground or insulation damage in the solar panel, junction box, DC cable, inverter, AC cable, terminal block, etc. The PV terminal block and AC wiring housing are loose, causing water ingress.

Solution: Disconnect the power grid and inverter, check the resistance of each component's wire to ground in turn, find out the problem point, and replace it.

5. The screen shows that the output leakage current is too high

Fault analysis: Leakage current is too large

Solution: Remove the PV array input terminal and check the peripheral AC power grid. Disconnect both the DC and AC terminals and let the inverter power off for more than 30 minutes. If it can be restored by itself, continue to use it. If it cannot be restored, contact the after-sales technical engineer.

6. The screen shows that the mains voltage is out of range

Fault analysis: The grid voltage is too high. The grid impedance increases, and the photovoltaic power generation user side cannot digest it. When it is transmitted out, the impedance is too large, causing the inverter output side voltage to be too high, causing the inverter to shut down for protection, or derating operation.

Solution:

(1) Increase the size of the output cable, because the thicker the cable, the lower the impedance.

(2) The inverter is close to the grid connection point. The shorter the cable, the lower the impedance.