Understand common inverter alarm issues

As the "heart" of photovoltaic power generation, the health of the inverter is closely related to the smooth operation of the photovoltaic power generation system. Understand common inverter alarms, accurately determine the cause of inverter alarms, and be the "family doctor" of your own inverter to ensure smooth operation of the inverter.

1. Inverter alarms caused by non-internal devices

If the screen or APP displays "Warning 103 or Warning 105", it means that reading and writing EEPROM failed. Generally, restarting the inverter can fix it. If "Warning 100 or Warning 400" is displayed on the screen or APP, it indicates a fan alarm. First check whether the fan is stuck by foreign objects, then manually stir the fan in the power-off state, and restart the inverter. It is recommended that the inverter fan should be cleaned regularly every six months.

2. Common inverter alarms caused by external environment
3. LCD displays “No AC Connection”.

This type of alarm indicates "no mains connection" and generally appears in single-phase inverters, indicating that there is no mains connection or the AC circuit breaker is disconnected. If this kind of alarm occurs, you need to check whether the AC side line connection is good and whether the AC switch is closed.

2. The LCD displays “Overtemperature”.

This type of alarm indicates "inverter overtemperature." Usually, the place where the inverter is installed has insufficient ventilation, the inverter is exposed to the sun, and the inverter fan is abnormal, which are all causes of the inverter overtemperature. To solve this problem, you first need to ensure ventilation where the inverter is installed to prevent the inverter from being exposed to the sun. For abnormal fan problems, you need to check whether the NTC line and NTC temperature sampling circuit are well connected.

3. The LCD displays “PV Isolation Low”.This type of alarm indicates "insulation resistance is too low." The cause of this problem may be due to the influence of panel insulation, cable insulation, component bracket grounding reliability, installation site temperature and humidity, etc.

To check this abnormality, first disconnect the AC and DC circuit breaker, use a special MC4 disassembly wrench to remove the positive and negative poles of the DC measurement string, then use a multimeter in the megohm range, connect the red test lead to the positive pole of the string, and the black test lead to ground, and read Measure the impedance reading of each positive pole to ground, then connect the red test lead to the negative pole of the string, and read the impedance reading of each negative pole to ground one by one. If it is greater than 50kΩ, the inverter determines that the string insulation is reliable, and it is less than or equal to 50kΩ. Then the inverter determines that there is a problem with the string insulation, and the inverter will automatically protect and stop working and report "insulation resistance too low".

4. The inverter screen does not display.The inverter does not display because the LCD has no DC input or the auxiliary power supply is abnormal. At this time, you need to use the voltage range of a multimeter to measure the DC input voltage of the inverter. The total voltage is the sum of the voltages of each component, which eliminates voltage problems. After eliminating the voltage problem, check whether the DC switch, wiring terminals, cable joints, components, etc. are normal.

The above is an analysis of the causes of common inverter alarms and general treatment methods. When the above methods cannot repair the inverter alarm, please contact the relevant staff in time and do not force the repair by yourself.