The diagnosis method of discharge characteristics in UV illumination gap using fiber sensor is presented.Compared with the conventional electromagnetic sensors

the fiber sensor has more advantages under certain conditions.Illumination experiments indicate that the fiber sensor can give the discharge characteristics in UV illumination gap qualitatively

and the fiber sensor is more suitable for detecting the starting time of discharge in UV gap;The light spectrum of UV illumination consists of ultraviolet

infrared

and visible light

and the first discharge peak in UV gap contains higher ultraviolet radiation than others.The breakdown experiment of the switch shows that the breakdown delay is about tens of nanoseconds

and the jitter of switch closely depends on the jitter of UV gap.