A: In the whole photovoltaic system, the DC side voltage is usually as high as 600-1500vdc. Due to loose contact, poor contact, damp wire, insulation rupture and other reasons, it is very easy to cause DC arcing. The high temperature generated by the arc is very easy to lead to fire when the adjacent substances reach the ignition point, that is, DC arcing is a potential safety hazard. AFCI function by identifying the arc fault characteristic signal in the circuit, AFCI will disconnect the power supply before the arc fault develops into fire or circuit short circuit, which greatly increases the system safety.