Technique for safety design of grounding grid in MEA´s power distribution substation

The study is separated into 2 parts. Part 1 involves characteristic of uniform soil. If the upper layer of two-layer soil is greater than 16 m, it can be treated as homogeneous one. Part 2 deals with the significant factor and give some suggestions that grounding system designer should know before design. The main objective of this paper is to be used as preliminary guide for first hand designer in his or her grounding system design before study the detailed part. The purpose of grounding system is to protect properties and loss of life caused by fault. There are 3 unsafe conditions: Case 1) maximum touch voltage exceeds the safety criteria. In this case, the conductor compression ratio of the ground gird should be firstly adjusted until optimal voltage is obtained. If the voltage still exceeds the limit, soil resistivity of the ground where ground grid situates should be considered next. Case 2) maximum step voltage exceeds the safety criteria. In this case, increase the number of ground grid conductors around the boundary of the grid help solve this problem. Case 3) both of the maximum touch and step voltage exceed the safety criteria. In this case, follow the above mentioned solutions of case 1 and 2. Another useful suggestion, you can vary the depth of ground grid until maximum step and touch voltage fall into the limit of the safety criteria. Modeling and simulation done throughout the paper is by the Current Distribution Electromagnetic interference Grounding and Soil structure (CDEGS) program. The simulation results exhibit the design and analysis of power system grounding and perhaps could be set as a standard in grounding system design and modification in distribution substations.