Common Faults of PV Inverters

Know about PV inverters

PV inverter is one of the important balance of system (BOS) in the PV array system, which can be used with general AC power supply equipment. Solar inverters have special functions to cooperate with PV arrays, such as maximum power point tracking and island effect protection.

Microtek solar inverters

Six common faults of PV inverters

• Low insulation resistance. Use the elimination method. Unplug all the strings on the input side of the inverter, and then connect them one by one. Use the function of the inverter to detect insulation resistance during startup to detect the problem string. After finding the problem string, focus on checking whether the DC joint has water-soaked short-circuit support or burnt to short-circuit support. In addition, it can also check whether the component itself has black spots burnt out in the edge area, causing the component to leak electricity to the ground grid through the frame.

• Low bus voltage. If it occurs in the morning/evening, it is a normal problem because the PV inverter is trying to generate electricity under extreme conditions. If it occurs during normal daytime, the detection method is the same as item 1.
  

• Leakage current fault. If the leakage current is too high, remove the PV array input end, and then check the peripheral AC power grid. Both the DC end and the AC end are disconnected, and the inverter is powered off for 30 minutes. If it can be restored by itself, continue to use it. If unable to restore, please contact a professional engineer.
  

• Overvoltage protection of DC. With the improvement of the efficiency of the components, the power level is constantly updated and rising. At the same time, the open-circuit voltage and working voltage of the components are also rising. The temperature coefficient problem must be considered during the design phase to avoid hardware damage caused by overvoltage at low temperatures.
  

• No response when the PV inverter starts up. Please ensure that the DC input line is not reversed. Generally, the DC joint has an anti-stupid effect, but the crimping terminal does not. It is important to carefully read the inverter manual to ensure that the positive and negative poles are connected before pressing. The inverter has built-in reverse connection short circuit protection, and it will start normally after the normal connection is restored.
  

• Power grid fault. The early-stage investigation of the heavy load (large working time)/light load (small working time) of the power grid is reflected here. Pre-investigation of the health of the grid voltage and communication with the inverter manufacturer on the grid conditions can ensure that the project design is within a reasonable range, especially for rural power grids. The PV inverter has strict requirements for grid voltage, grid waveform, and grid distance. The majority of the reasons for overvoltage problems in the power grid are that the voltage of the original power grid under light load exceeds or approaches the protection value of the safety regulations. If the grid connection line is too long or the crimping is not good, causing the line impedance/reactance to be too large, the power station cannot operate stably.

  
  

Microtek is one of the top and best PV inverter manufacturers in the world.

You may also want to know about our other types of solar inverters:

Off-Grid Solar Inverter

Hybrid Solar Inverter

Single-Phase Solar Inverter

Home Solar Inverter

MPPT Solar Inverter

Recommend reading:

https://www.microtekenergy.com/microtek-solar-solutions-off-grid-energy-storage.html