Generally, as long as the inverter is in the grid-connected state, the power curve displayed by the monitor is a normal “mountain” line, which proves that the power station is running stably. If there is an abnormality, you can check the health status of the supporting equipment of the power station through the information fed back by the inverter. The basic information and processing methods are listed below:
1. Low insulation resistance: Use the method of elimination. 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 when starting up the inverter to detect problem strings. After finding the problem strings, focus on checking whether the DC connector has a water-immersed short-circuit bracket. Or burn the short-circuit bracket. In addition, you can also check whether there are black spots on the edge of the component itself, which causes the component to leak electricity to the ground grid through the frame.
2. Low bus voltage: If it occurs in the early/late hours, it is a normal problem because the inverter is trying to limit the generating conditions. If it occurs during normal daytime, the detection method is still the exclusion method, and the detection method is the same as item 1.
3. Leakage current fault: The root cause of this type of problem is the installation quality problem, which is caused by choosing the wrong installation location and low-quality equipment. There are many fault points: low-quality DC connectors, low-quality components, unqualified installation height of components, low-quality grid-connected equipment or water leakage. Good insulation work solves the problem, if it is a material problem, you can only replace the material.
4. DC overvoltage protection: With the pursuit of high-efficiency process improvement of components, the power level is constantly updated and rising, and the open circuit voltage and operating voltage of components are also rising. The temperature coefficient must be considered in the design stage to avoid overvoltage in low temperature conditions and cause equipment hard damage.