A new approach for mitigating voltage unbalance in a three-phase two-wire rural distribution network

Abstract

The three-phase two-wire distribution system is an unconventional proposal for the repowering of single wire earth return electrical networks, intended for use in remote rural areas as it allows cost reduction by using only two overhead conductors and the ground as the third phase. An intrinsic characteristic of this system is the voltage unbalance observed near the loads, resulting from impedance mismatches between overhead conductors and the ground. The main objective of this work is to explore methodologies for minimizing voltage unbalance by strategically introducing impedance elements in targeted sections of the distribution network. A novel simplified equation for line-to-line compensation based on network parameters, along with a precise computational methodology to determine optimal compensation values, are proposed as contributions to the state of the art. The simulations in MatLab/Simulink demonstrate that the arrangement in which the compensation elements are added to the system directly impacts the voltage unbalance. Moreover, the study demonstrates the efficacy of the developed computational methodology in effectively reducing unbalance within extensive distribution networks.