The electric energy loss in overhead ground wires of 110kV six-circuit transmission line on the same tower

In order to provide theoretical guidance for reducing the electric energy loss of 110kV six-circuit transmission line on the same tower, the factors affecting electric energy loss in overhead ground wires are deeply studied. Firstly, the model of 110kV six-circuit transmission line on the same tower is established in MATLAB. Secondly, the effect of phase sequence arrangements on electric energy loss is studied. Finally, the effects on electric energy loss of varying relative position between two overhead ground wires, horizontal distance and vertical distance among transmission lines are studied. The results show that phase sequence arrangements have a great influence on power loss in overhead ground wire. The inverse phase sequence arrangement is validated to be optimized layout. The electric energy loss is positively correlated with horizontal distance between two overhead ground wires and negatively correlated with vertical distance from overhead ground wires to the ground.

I. Introduction

MULTI-CIRCUIT transmission line on the same tower is more widely used in power system in recent years, because it can not only increase the transmission capacity to satisfy the power demand of the rapid development of national economy, but also reduce the width of corridor of transmission lines to cover smaller area. Especially for densely populated areas, compensation for demolition and resettlement and construction cost of corridor are greatly reduced by building multi-circuit transmission line [1], [2]. However, lightning protection performance of multi-circuit transmission line becomes poor, because it's corridor is wider and it has higher tower, which make triggering lightning area bigger than single-circuit transmission line. Therefore, lightning outage rate of multi-circuit transmission line increases and higher overvoltage is caused by lightning current [3], [4]. Erecting ground wires is the most basic and effective lightning protection measure for high-voltage and extra-high voltage transmission line. In order to ensure power supply reliability, overhead ground wire should be set up along with the entire length of 110kV transmission line, and two ground wires should be set up for 220kV, ultra-high voltage and extra-high voltage transmission line [5] [6] [7].