Cost-Effective Optimization Model for Transmission Line Outage Rate Control Due to Back-Flashover Phenomena

Abstract

This paper presents a cost-effective optimization model for transmission line lightning performance design. The objective is to determine the appropriate insulation level and a particular grounding scheme of each support for a given line outage rate requirement due to the back-flashover phenomena at a minimum overall cost. To ensure a minimum global investment cost, the constraints associated with the individual lightning behavior of each tower section are relaxed depending on the regional atmospheric activity and on the particular characteristics of the soil, and therefore on the costs of the required grounding and insulation systems at each tower location, enforcing the appropriate lightning behavior of the complete transmission line. The proposed model is based upon a linear-integer programing problem formulation and solutions are obtained from the application of a three-layer hierarchical design methodology. The proposal has been tested in a 230 kV transmission line, 85.4 km long, with 180 towers. Results are presented and compared with designs obtained through by a conventional grounding optimization with important reductions in investment costs, encouraging the use and further development of the methodology.