A practical approach for computation of grid current

Whe nagmundfitultoccursatasubstation,thepart of the fault current that flows between the groundihg system andthe sumuunding earth is known as grid current. This current dekmines the magnitude of the dangerous voltages within and around the station. It may vary fiom a few percent to almost 1WA of the earth fault current. It is necessary to make an accurate estimate of grid current for an economical and safe design of ground electrode. The available analytical methods for determining the grid current require complete system data, which is voluminous and often unavailable. In this paper a simple and accurate dyticai method for det- the grid current is presented. The method requires limited daw A computer program based on the proposed method has been developed and tested.