Solar energy has great potential for development and application for it is sustainable and clean. Photovoltaic technology was developed in 1950s, with the tightening of the global energy situation it has been rapidly developed in recent years. The Photovoltaic system consists of PV array, inverter, measuring appliances, junction box and other parts. Solar modules change the light energy into DC power, DC power is converted into AC power by inverter., and then the power can be connected to the grid or used for AC load. According to different applications, photovoltaic system can be divided into Residential rooftop system; commercial rooftop system and utility system; meanwhile it can also be divided into grid-connected system, off-grid system and hybrid system according to whether it can be grid-connected.