Effect of waveform and impulse resistance on lightning performance in distribution system

This paper presents the effect of lightning waveform to the voltage at the pole top and back flashover rate (BFOR). The result found that short front time of lightning current waveform or high slope will cause high voltage and back flashover rate at the top pole. However the tail time of lightning current waveform will not effect to the top pole voltage and backflash over rate because the impulse resistance will only affect to the long front time of lightning current waveform. In case of short front time, impulse resistance will not affect to voltage at the pole top and backflash over rate. Moreover BFOR will vary with the event of thunder storms per year. ATP-EMTP is used to simulate cases in this paper to receive pole top voltage, critical current and backflash over rate. The 69 kV subtransmission line system of Metropolitan Electricity Authority (MEA) is demonstrated as the case study to improve its grounding standard of subtransmission and distribution line system in MEA´s power system .