INVESTIGATIONS ON SINGLE PHASE EARTH RETURN SYSTEMS FOR RURAL DISTRIBUTION

Abstract

and scattered not justifying 3-phase supply on economic grounds. The use of less costly single phase earth return system. is advocated herein, for such areas where the immediate and future load demands are very small. The problems involved in .the use of earth as return conductor are analysed in detail. . The model tests are conducted to study the interference with neighbouring communication lines, the gradient problem and .to explore the _means_ of reducing surface poten-tials near the earth electrode. Field tests help to check the results obtained by analytical and model methods. A simple protective scheme is devised to provide protection against high resistance earth faults on such lines. A simple static over voltage relay is developed to prevent build up of hazardous potentials near the earth electrodes. The need to make available single phase motors required in the rural areas at reasonable cost% and the use of existing 3 phase motors on single phase supply in con1uction with a capacitor or through phase converter is strongly advocated. The cost of the 3 phase transmission system ,and the single phase earth return system is worked out to show the saving in capital investment by use of the single phase earth return system