What is the effect of low insulation resistance of photovoltaic power generation systems?

Photovoltaic system after installation, the user is more concerned about power, because it is directly related to the user's return on investment. There are many influence factors in generating capacity, the quality of the components, inverter, cable, install toward the azimuth Angle and tilt Angle, dust, shadow

photovoltaic system after installation, users pay more attention to power generation, because it is directly related to the user's return on investment. There are many influence factors in power generation, such as components, inverter, cable quality, installation of azimuth and dip Angle, dust, shade, component matching with inverter system, circuit design, construction, power grid voltage is possible. The following mainly discuss the effects of low insulation resistance on the system. Inverter is the principle of testing insulation resistance: photovoltaic inverter by testing ground and pv voltage to the ground, photovoltaic (pv) + are calculated respectively and photovoltaic resistance to the ground. If either side of the resistance value is lower than the threshold, the inverter will stop working, and sound an alarm, display 'photovoltaic low insulation resistance. Low insulation resistance is a common fault of pv systems. Components, the damage of the DC cable and connectors, and insulation aging will lead to low insulation resistance. When the DC cable across the bridge, due to the edge of the metal bridge agnail, the outer insulation of the cable skin may be damaged in the process of threading, lead to leakage. The harm of low insulation resistance: low insulation resistance can lead to system leakage, if the inverter is connected to the grid, can lead to electrical equipment enclosure charged, the safe hidden trouble that bring people get an electric shock; To the ground from the fault point discharge may cause local heating or electric spark, resulting in fire and other safety hidden trouble. For the 'photovoltaic insulation impedance is too low', general can adopt the following methods: 1) On-site inspection DC cable grounding and components first, insulation impedance abnormal reason is due to the DC cable damage, including the components between the cable, cable between components and inverter, especially in the corner of cable without cable pipe, and outdoor need to carefully check whether damage. Second, bad earth photovoltaic system, including module grounding holes not connected, module briquetting and support poor contact, part of the branch cable casing submerged and lead to low insulation resistance. 2) Relying on the inverter by string to check if the inverter DC side is multiplex access, will be one by one to check the method to test the parts. The DC side of the inverter only keep a list of components. After startup, check whether the frequency converter is continue to report errors. If you don't continue to report errors, the connection of components with good insulation performance. If you continue to report errors, is likely to be the component list of insulation is not in conformity with the requirements. Or, for example, 20 kw inverter is connected to the 4 and pulled out a circuit. If fault alarm disappear, show that the series of defective. 3) Detection using a piece of string table or other professional equipment by on-site inspection, the components should be measured using a piece of string vibration table by lateral photovoltaic pv + / grounding insulation resistance. Impedance should be greater than inverter insulation impedance threshold requirements. In some projects, also can use special insulation measurement equipment. Before the components connected to the inverter, group must detect series insulation resistance to the ground, it is very necessary and indispensable steps.