Evaluation of Improved Transient Behaviour of Single Wire Earth Return under 22 kW Motor Starting Conditions

Abstract

A Single Wire Earth Return (SWER) is a distribution system that supplies power to rural areas or farms. The cost-benefit of implementing this distribution system yields a third of the cost compared to the traditional three-phase distribution system. The types of loads a SWER line is designed to supply are domestic loads, which are mainly resistive loads. A 22-kW motor during starting conditions is not resistive but is predominantly inductive; furthermore, the motor creates transients on the line it supplies. An experiment was conducted to determine Single-Phase Induction Motor (SPIM) parameters. These tests were performed following the Institute of Electrical and Electronics Engineers standards under two different running conditions: a no-load (light) test and a load (locked rotor) test. MATLAB, SimPower Systems software were used to simulate the transient behavior of the SWER line under starting conditions. The study has concluded that a SPIM connected at the end of a SWER line will lead to a large voltage depression on other healthy loads. There are numerous ways in which a consumer can enjoy the benefits of the SWER system that are recommended and the cheapest method is suggested in this paper. Utilities, government departments, scholars and consumers need to be educated about this electrification method, particularly in South Africa where the SWER line is considered an inferior power supply.