Safety impacts of electric potential and electromagnetic fields as result of faults in electric distribution system

摘要

This article investigates the impacts of electric potential (EP) and electromagnetic fields (EMF) on human health, especially for those living or working near a distribution system, as a consequence of faults inside the distribution system supplied by an outdoor substation. A case study was carried out using a 115/22 kV substation and a 22 kV distribution system of Thailand's Provincial Electricity Authority (PEA), with simulated faults injected at the top of a pole of distribution lines located at three different locations. Two methods were proposed for EP and EMF reduction: 1) bonding the ground grid of the substation and the ground rod of the riser pole, and 2) connecting the overhead ground wires of the substation and that of the distribution system. The study results confirm that the two proposed methods offer practically effective problem-solving solutions for reducing EP, and they are therefore able to mitigate the risk of equipment damage. The spatial distribution of EMF measured in the vicinity of the distribution system was found to comply with the threshold set by the International Commission on Non-Ionizing Radiation Protection (ICNIRP) and the International Radiation Protection Association (IRPA), indicating that those living or working outside the substation were safe.