Research On Identification Method Of Series DC Fault Arc In Photovoltaic System

Solar energy has become one of the most potential energy sources in the future energy field because of its clean and benefits for environmental protection.However,with the rapid development of the photovoltaic industry,the frequency of the photovoltaic system fire continues to rise,which seriously threatens the reliability of the safe operation of the photovoltaic system.Research shows that the DC fault arc is the direct cause of the photovoltaic system fire,and the characteristics of arc fault are high temperature,high heat,short holding time and is difficult to be detected.In order to ensure and improve the stability of the safe operation of the photovoltaic system,the No.690.11 of 2011 National Electrical Code(NEC)has made the compulsory installation of the fault arc circuit breaker in the photovoltaic system.Therefore,timely and effective identification of DC arc fault in PV system has important research value to avoid fire damage.This paper analysed and summarized the research results of DC fault arc identification and detection at home and abroad.The causes of DC fault arc and the principle of fault arc detection are systematically introduced.The DC fault arc generator is designed and produced according to the UL1699 B standard of the American insurer’s laboratory.The experimental platform of DC fault arc in PV system is built,the current data of fault arc is collected by the sensor.According to the experimental data,the identification method of the DC fault in photovoltaic system is studied.The combined method of fault arc recognition for PV system which contains the variance of current,the maximum value of current shift,the proportion of high-frequency energy,the variance of high-frequency components,the EMD decomposition of imf5 component modulus maxima,and the EMD energy entropy is proposed and verified to be effective in identifying DC fault arc in photovoltaic system.The research of this paper is of great significance to prevent the fire caused by DC fault arc in the photovoltaic system.It is of reference significance for the study of the characteristics of DC fault arc in PV system,and has certain reference significance for the study of DC fault arc circuit breaker and detector.