Huawei photovoltaic inverter insulation resistance

What happens if the ground resistance of a solar inverter is too low?

If the ground resistance of a PV string connected to a solar inverter is too low, the solar inverter generates a Low Insulation Resistance alarm. A short circuit occurs between the PV array and the ground. The ambient air of the PV array is damp and the insulation between the PV array and the ground is poor.

How do I find a ground insulation fault in a solar inverter?

If two or more ground insulation faults occur in a single PV string, the following method cannot locate the fault. You need to check the PV modules one by one. The AC power supply is connected, and set the DC switch at the bottom of the solar inverter to OFF. Connect each PV string to the solar inverter and set the DC switch to ON.

How to measure the insulation resistance of a photovoltaic module?

Measure the insulation resistance (+,-) polarities of each cable and the ground for one string of module array to verify that there is no insulation failure. Note: The insulation resistance of the cable including the photovoltaic modules will be measured. Acceptable value if measurement is done by using 1000V Megger is 400KΩ or higher.

How do I check if my solar inverter is low insulation resistance?

If the Low Insulation Resistance alarm is not reported one minute after the DC is supplied, choose Device Commissioning > Maintenance > Inverter ON/OFF on the app and send a shutdown command. Set the DC switch to OFF and go to Step 2 to connect another PV string to the solar inverter for a check.

How to set insulation resistance protection in rainy and cloudy days?

If the impedance is lower than the specified protection threshold in rainy and cloudy days, set Insulation resistance protection using the mobile app, SmartLogger, or NMS. Current insulation resistance: x MΩ, possible short circuit position: x%. The short circuit position is valid for a single PV string.

How do I check if a PV string is low insulation resistance?

If the Low Insulation Resistance alarm is not reported one minute after the DC is supplied, the inspection on the PV string is complete. Choose Device Commissioning > Maintenance > Inverter ON/OFF on the app and send a shutdown command. Set the DC switch to OFF. Go to Step 2 to check other PV strings.