Grounding locations assessment of practical power system

Grounding Points (GPs) are installed in electrical power system to drive protective devices and accomplish the person- nel safety. The general grounding problem is to find the optimal locations of these points so that the security and reli- ability of power system can be improved. This paper presents a practical approach to find the optimal location of GPs based on the ratios of zero sequence reactance with positive sequence reactance (X0/X1), zero sequence resistance with positive sequence reactance (R0/X1) and Ground Fault Factor (GFF). The optimal values of these indicators were deter- mined by considering several scenarios of fault disturbances such as single line to ground on a selected area of the Iraqi National Grid (132 KV) taking into account the statue of GPs for transformers in the other substations. From the pre- sented results in this paper, it is noted that GFF calculated for some substations could be used to measure the effective- ness of GPs. However, the operated time of relay can be taken as a criterion of this measurement for selecting the best location of GPs.