On-site partial discharge measurement of uderground cable system

Partial discharge diagnosis technology may offer valuable information on the dielectric defect, such as type of failure, and influence of service life cycle of power equipment. The main measuring methods of on-line partial discharge instrument are detection the characteristics of electric transient signal, radio signal of electromagnetic emissions, chemical component deformation, vibration, sound, flush and thermal effect. For analyzing the location of defection and distinguishing the partial discharge signal from noise, the construct of equipments, the frequency band of sensors and signal attenuation should be provided. Here we measured the amplitude of partial discharge quantity, phase distribution, and the discharge influence by voltage variation. We estimate the life cycle of equipment according to the measured information in this paper.