Research of influence pattern of lightning current on impulse characteristic of ground device for pole and tower

A majority of failures in power transmission line are due to trip-out in power transmission line as a result of lightning strike on power transmission line or pole and tower, how to reduce trip-out rate in transmission line becomes focus of attention in electric power system at the present time. The paper has established model for lightning current amplitude and impulse coefficient of ground device of pole and tower. X-ray photograph platform for spark discharge in soil shall shoot the gradual change process of spark discharge in soil from light lightning current to heavy lightning current; spark discharge is process pattern from spot, sphere, streamer to arc channel, the equivalent conversion pattern of impulse characteristic parameter of ground device for high and light lightning current is obtained based on research of spark coefficient and inductance coefficient so as to achieve the method to know impulse characteristic of ground device under the action of heavy lightning current by light lightning current impulse testing, in which small portable type impulse ground impedance tester is adopted to carry out testing of impulse ground impedance of pole and tower precisely, which shall play a guidance role in lightning protection design, evaluation, construction and renovation of power transmission line.