Substation earth grid measurement using the fall of potential method (FOP) for a limited test area

The neighboring rates between high voltage substation and residential buildings are amplified due to populations increase. To guarantee safety acquiescence of the new system, earthing system design is required. Earthing system offers a safe working atmosphere for employees and people transitory by during a fault or malfunction of a power system. The design process is based on few assumptions therefore it is critical to measure the designed grid resistance to ensure its compliance. Fall of potential method is frequently used to measure the earth grid resistance of the high voltage infrastructure. The locations of the current and the potential probe play an important role that leads to accurate results. The current standards include the minimum separation between the current probe, potential probe and the tested grid. The minimum separation may not be achieved under limited space area. The paper endeavors to deliver information in regards to the `Fall of Potential´ (FOP) Method. It comprises the minimum separation required between the current probe and the tested grid. Furthermore, the novel position of the potential probe when the minimum separation between the current and earth grid under test cannot be established is examined. The case study results show the advanced accuracy in the tested result when deploying the novel method as provided in this paper.