IMPROVING LIGHTNING PERFORMACE OF TWO RATED VOLTAGE MULTI CIRCUIT TRANSMISSION LINES BY USE OF LINE SURGE ARRESTERS

Abstract

Multi-rated-voltage multi-circuit overhead transmission lines are increasingly used because of their reduced construction costs, and right-of-way requirement. However, using these transmission lines bring along with disadvantages in terms of lightning protection. This paper studies application of line surge arresters to reduce lightning outage rate for four-circuit transmission line with two rated voltage levels of 220 kV and 110 kV built on a single tower. The study utilizes Electro-Geometric Model (EGM) method and EMTP/ATP simulation software. Outage rate in cases of different arrangements of line surge arrester are evaluated and compared. Effect of parameters such as tower footing resistance and tower height are analyzed. Absorbed energy and current through line surge arrester are also determined as basic for selection of suitable line surge arrester.