Lightning Risk Assessment on Outdoor HV Substations Based on IEC 62305-2: A Case Study

Abstract

The importance of having lightning risk assessment for the outdoor high voltage substations is to minimize the injury rate of the operators while working at the substations and to ensure the continuity of power supplies to the public. Many electric utilities and practitioners are reluctant to apply IEC 62305-2 due to the lack of direction to perform the lightning risk assessment for the substations. Therefore, the electric utilities and practitioners usually select their preferred methodologies based on IEEE 998 which lacks coherence while performing the lightning protection design for substations. This study will demonstrate the applicability of the lightning risk assessment for substations based on IEC 62305-2. The dimensions such as lightning collection areas for substations can be determined via computer-aided design (CAD) software. These site features will be used for the lightning risk assessment by similarly representing the substations as the building structures. It is shown that some of the ambiguous risk factors such as loss reduction factor due to physical damage depending on the risk of fire or explosion and injury loss value due to loss of internal systems which have a significant gap between ranges of risk values will dominantly influence the variation in the results. Besides that, the lack of selection criteria and the vagueness of risk values that are used to represent the actual substations case are highlighted. Therefore, this paper has shown some major risk components usually appeared in substations. However, the individual risk factor values of each component shall be revisited as some of the dominant ambiguous risk factors may contribute towards the misrepresentation of the results.