大気中正棒対平板ギャップのインパルスおよび直流フラッシオーバ

抄録

Discharge phenomena in positive rod to plane air gaps under lightning impulse and DC voltages have been investigated. Under impulse voltages, the 50% flashover voltage V₅₀ agrees with the 50% corona inception voltage for the gap shorter than d_c which depends upon the rod diameter φ. V₅₀ at d_c rises with d_c at a rate of about 14kV/cm for d_c<2.8cm(φ<1.5cm), whereas, it rises at a rate of about 5kV/cm for d_c>2.8cm(φ>2cm). Experimental results show that the flashover process in the former region (G_p process) is different from that in the latter region (L_p process). Under DC voltages, the critical gap length, for which the first corona may lead to flashover with no successing corona, corresponds to d_c. In the gap shorter than d_c flashover occures through G_p or L_p process, but in the gap longer than d_c, flashover may occur through another process which can not be seen under impulse voltages.
The present paper describes these flashover characteristics and processes with experimental results on the basis of photographic observation with an image converter camera.