Supply Auto-Restoration using Automated Normally Open (N/O) point on Medium Voltage (MV) Networks for the Fault Location, Isolation and Service Restoration (FLISR) Technology

Abstract

Medium Voltage (MV) Overhead Lines (OHL) are normally designed in a radial nature which results in back-feeding challenges. MV feeders are usually long in length and that exposes them a huge deal to faults. Major attention has to be paid to these networks since they create faults which affect customers. It is therefore essential to develop self-healing Smart Grid technologies to improve the performance of these networks and to ensure minimum customer interruption during an outage. One such technology is Fault Location, Isolation and Service Restoration (FLISR). The key motivation of implementing FLISR is to advance the utility’s network reliability. This paper addresses ways to implement FLISR and it focuses on a real distribution network case study and it looks at the issues associated with closing a remotely controlled or automatically operated Normally Open (N/O) point for back-feeding purposes. The benefits of implementing an automated service restoration to Eskom are to minimize the number of customers affected by a fault by automatically isolating the faulted location and restoring service to the healthy portion of customers. This will ultimately minimize the number of customer-hours interrupted (SAIDI) to the values required by the National Energy Regulator of South Africa (NERSA).