CALCULATION FOR LIGHTNING PERFORMANCE IMPROVEMENT OF GROUNDING ELECTRODES OF EVN HANOI MEDIUM VOLTAGE DISTRIBUTION LINES

Abstract

Failure rate due to lightning strikes on the distribution lines of EVNHanoi is quite high during the past
years. Lightning strikes can lead to the equipment damage and interruption of power supply of
overhead distribution lines. The grounding electrode system should be calculated and designed to
improve the lightning performance of these lines. This study then proposes a method to calculate the
DC resistance and the impulse impedance in the time domain of the grounding electrode by
numerical simulation. The simulation was applied to the grounding electrode of EVN Hanoi
distribution lines. The obtained results allowed to verify and recommend suitable electrode
configurations for areas with high soil resistivity values and can be widely applied to medium voltage
distribution lines.