Safety analysis for grounding system of two neighbouring substations in MEA´s power distribution system

This paper presents construction planning procedures for a new permanent substation to replace an small (temporary) substation that is served to supply the load of the old existing substation while it has not been removed. In the meantime when the ground grids of the two substations are electrically disconnected, the auxiliary grounding system of substation can create steep ground potential rise between the ground grids of the two substations and hence introduces a risk for those who are working nearby. It is therefore important to incorporate safety criteria described in terms of step and touch voltage into electrical designs without any potential electrical hazards. The safety design planning process is illustrated by the Pathumwan (PM) substation of Metropolitan Electricity Authority (MEA). Modeling and simulation is carried out on the Current Distribution Electromagnetic interference Grounding and Soil structure (CDEGS) program. A sequential transition process from the small substation to a permanent substation is suggested to comply with the IEEE standard 80-2000.