Abstract: For PV system,from the PV panel to inverter input,there is high voltage direct current during daytime.It is necessary to have a better arc detection and protection methods to guarantee the safe and stable operation of the photovoltaic system.This paper gives a detail description of the DC arc formation mechanism,and a detailed DC arc detection and protection design of PV system.The time domain and frequency domain analysis of frequency spectrum was adopted,and with the cyclic detection of PV system spectrum-parameter signal,the arc fault is detected,tracked and judged in real time.Moreover,the disturbance clutter and crosstalk signal of the sampling process are processed by DSP filtering to prevent the false triggering signal,and the final results of arc fault detection is systematically protected to prevent the damage of DC arc.

Key words: PV system, DC arc, arc fault, frengency spectrum analysis