In order to avoid or reduce arc fault hazard

the authors established an arc fault detecting test system with the method of power spectral analysis to study the early acoustic characteristics of fault arc

and extracted the sound signature of early fault arc by using power spectrum analysis.The results show that the signature band of sound wave is within the range from 5 kHz to 10 kHz before fault arc taking place

and variable in both width and center with different electrode shapes

space between electrodes

and discharge voltage.By monitoring the existence of weak arc in this band

early detection and warning of switchgear arc fault can be realized.