A simplified method for optimizing line shielding angle to maximize lightning performance

Abstract

The lightning performance of overhead transmission lines is affected by many factors. Most of those factors are nature driven and are not predictable or controllable. Of those controllable factors affecting a line's lightning performance, the one that can be dealt with most cost-effectively is the transmission line's shielding. However, at some utilities, the design and selection of the line shielding method for transmission and sub-transmission lines operating at nominal voltages between 46 kV and 230 kV is typically relegated to a secondary level of importance because of the complexity of the calculations involved and an inherent reluctance to change. This paper presents a simplified method for optimizing the transmission line shielding angle to minimize the line's predicted lightning performance. The proposed method for optimizing the line's shielding angle relies on known formulas and procedures developed over the past four decades. The simplified method presented can be used by utilities in upgrading their current line shielding practices.