A New Calculation Method of Breakdown Voltage-Time Characteristics of Long Air Gaps

A new calculation method of leader development which considers predischarge currents is proposed. Calculated leader delopment characteristics with this model are compared with photographs of a image converter camera and close agreement is shown. Further, breakdown voltage-time characteristics of rod-plane and rod-rod gaps with standard and non-standard lightning impulses of both positive and negative polarities are calculated and these values agree with experimental results. This new calculation method is applicable to long gaps of several meters.