An Industry Practice Guide for Underground Cable Fault-Finding in the Low Voltage Distribution Network

Abstract

This paper aims to critically analyze the IEEE Std 1234-19 and other power cable fault-finding technical guides produced by leading industries to assess their applicability in practice to the underground low voltage distribution network (LVDN). The analysis reveals that there is no clear distinction between the fault-finding techniques and procedures of LV and MV/HV systems. Innumerable branching to residential loads in the underground LVDN makes them unsuitable to the application of most of the fault-finding techniques mentioned in the IEEE Std 1234-19 that are effective for MV/HV networks. Moreover, state-of-the-art techniques which are used as part of common industrial practice for LV fault-finding are not mentioned in the standard, nor collectively in any technical industry guide, which gives the impression that the content applicable to LV fault-finding is insufficient and lost amongst content only applicable to MV/HV fault-finding. In this paper, further contribution is provided; by means of presenting a recommended guide to fault-finding in the underground LVDN that will comprehensively fill in the knowledge gaps from the IEEE Std 1234-19 and other technical guides. The recommended guide presented in this paper is formed from practices reported in literature in addition to in-field case studies from one of UK’s largest energy providers; Scottish Power Energy Networks (SPEN) - part of Iberderola. The paper presents and discusses these literature-based and practical-based fault-finding practices, and uses them to construct the proposed guide which is presented in the form of a detailed flowchart procedure. This procedure is put forward to industry practitioners to be used in conjunction with existing technical standards and industry guides.

Keywords

• Cable faults
• fault-finding
• low voltage distribution network (LVDN)
• underground power cables