POTENTIAL DISTRIBUTION MEASUREMENT OF SURFACE DISCHARGE BY POCKELS SENSING TECHNIQUE

A new technique for measuring the transient potential distribution of electrical discharge is proposed, The measuring system consists of a B i4Ge3O12 Pockels crystal, an Ar ion laser, a beam expander, a streak c amera and a charge-coupled device camera. The potential profile of the discharge along a linear path of 50 mm in length is measured in the r ange of 0 similar to+/-36 kV. The temporal and spatial resolutions of this system are estimated to reach 2 ns and 0.1 mm, respectively. The potential distribution of a surface discharge creeping on a dielectric material is measured to clarify its developing mechanism. The tip of the propagating surface discharge has a high potential close to an app lied potential. The maximum value of electric fields of a negative sur face streamer exceeds 16 kV/cm in the direction of the streamer propag ation. (C) 1998 American Institute of Physics.