Abstract: Because the photovoltaic power generation system will continue to generate electricity in the presence of light, it can not cut off the power supply, and the use of traditional fire extinguishing agents will cause electric shock accidents. In order to analyze the electric shock risk of high voltage DC side of photovoltaic power generation system with live extinguishing agent, a test platform and test method are proposed. Through the test, it can be found that: foam, water-based fire extinguishing agent, carbon dioxide and other fire extinguishing agent in the DC side of 300~1 500 V high voltage, due to the insulation of the fire extinguishing agent, it cannot form a circuit and therefore lacks conductivity. Fire hydrant water gun and multi-functional water gun live rescue process gun head with DC voltage, the gun head voltage changes with the flow and distance, because the center of the water column of the multi-functional water gun is air, significantly reduce the conductivity of the water column, multi-functional water gun than fire hydrant water gun is more suitable for fighting the photovoltaic power generation system live fire. The calculation method of water conductivity of multi-functional water gun in the process of electricized rescue is obtained, and the safety distance of primary and secondary electricized rescue of water gun is calculated and determined. In the live rescue process, the rescue distance must be strictly greater than the first-level safety rescue distance, and corresponding protective measures must be taken to prevent electric shock within the second-level rescue distance.

Key words: photovoltaic power generation system, DC high-voltage, electric rescue, electric shock risk, conductivity