The Direction Of Decrease In The Impedance Of The Surge Arrester's Lead Wire

The residual voltage between lightning arrester in transformer and the protected equipment consists of three parts: the residual voltage of high voltage lightning arrester itself, the residual voltage on the lead-in line, and the residual voltage on the grounding device. During an overvoltage event, these three voltage drops act together on the distribution transformer, with the magnitude of the lead-in line impedance directly affecting the residual voltage value. The inductive characteristics of the conductor are significant under high-frequency currents; the higher the frequency, the stronger the conductor's inductance, and the greater the resulting impedance. According to Ohm's law U=IR, to reduce the residual voltage on the lead-in line, its impedance must be reduced.

Shortening the distance between 33kv lightning arrester and the distribution transformer is an effective way to reduce the lead-in line impedance. By reducing the spacing of the 10 kv lightning arrester arrangement, the voltage drop of the lead wire can be directly reduced. This installation method is more suitable for the side closer to the distribution transformer.