The influence of Urban Substation on Neighbouring Metal Grounding System

Abstract

With the development of China’s social and economic development, there are more high voltage substations in city and urban area. In order to better study the influence of fault current of urban substations on the neighbouring buildings, the paper studies the conduction interference between the urban substation with neighbouring merchants and civil buildings. Based on importance parameter, the surface potential, the conduction interference level of the civil substation system is quantitatively analyzed with different soil structure parameters, interval distance and the size change of the neighbouring grounding system. The research results show that, when the urban substation takes fault, even if there is no direct electrical connection, the surrounding commercial buildings and grounding system will be subjected to conduction interference. If do not considering the security of these grounding systems, it is easy to cause security risks. The soil structure is different, the influence of conduction interference is also different. The higher the soil resistivity in the bottom layer, more fault current will be scattered through the top soil, the more obvious the influence of conduction interference. With the increase of the size and distance between the neighbouring grounding system, the conduction interference effect will be reduced. In the design and safety analysis of the substation grounding system in the urban area, the safety of the surrounding buildings of the civil buildings should be considered. The research results provide theoretical basis and engineering guidance for the design of the grounding system in the urban substation and the safety protection of the commercial buildings surrounding the substation.