1. Low insulation impedance: use the exclusion method. Pull out all the strings on the input side of the inverter, then connect them one by one, using the function of starting the inverter to detect the insulation impedance, detecting the problem strings, after finding the problem group, focus on checking whether the DC joint has a water-immersion short-connect bracket or a melting short-connect bracket, it is also possible to check whether the component itself has a black spot at the edge that causes the component to leak through the frame to the ground grid.

2. Low bus voltage: this is a normal problem if it occurs during the early/late hours, as the inverter is trying to limit power-generation conditions. If present in a normal day, the test is still the exclusion method, the same test as 1 item.

3. Leakage current fault: this kind of problem is the root cause of the installation quality problems, the wrong installation location and low-quality equipment caused. There are many points of failure: low-quality DC connections, low-quality components, components installation is highly unqualified, low-quality grid-connected equipment or water leakage, once a similar problem, you can solve the problem by finding the spots in the powder and doing the insulation work, if the material is the province of the problem can only replace the material.  

4. DC over-voltage protection: with the pursuit of high efficiency process improvement, the power level is constantly updated and rising, and the open circuit voltage and working voltage of the module are also rising, the temperature coefficient must be considered in the design phase, avoid low-temperature conditions lead to excessive pressure equipment hard damage.

5. Inverter start-up non-response: Please ensure that the DC input line is not connected back, the general DC connector anti-nerd effect, but the voltage terminal does not anti-nerd effect, it is important to read the inverter specification carefully to make sure that the positive and negative electrodes are followed by crimping. Inverter built-in reverse short-circuit protection, in the return to normal wiring after the normal start.

6. Grid Fault: may occur grid over-voltage, under-voltage, grid over/under-frequency, network no-voltage, network lack of phase and other faults, check grid-connected lines, lack of phase circuit.