Research on Lightning Overvoltage of 110 kV Line of Canceling Ground Wire and Installing Composite Arrester Combined Insulator

The 110 kV transmission line passing the mountain areas is prone to severe icing on the conductors and overhead ground wires in winter as a result of micro landform and climate. While severe icing of the overhead ground wire will increase the sagging of the ground wire, causing the discharge of the phase wire to the ground wire and probably a disconnection accident. Since there is no effective ice-melting measure for the icing of overhead ground wires now, canceling the overhead ground wires is considered feasible to reduce icing accidents. The lightning strike problems caused by the removal of the ground wire will affect the normal operation of the line, so the composite arrester combined insulator with lightning protection function can be installed in the line to avoid this. This paper is based on the electromagnetic transient simulation software ATP, a lightning strike simulation model of the line without ground wire was built. The distribution law of lightning overvoltage on the tower top, composite arrester combined insulator insulation section, lightning protection section and wires is analyzed when the line is struck by lightning. The research results show that due to the special working principle of the composite arrester combined insulator, the lightning overvoltage will be clamped at a very low level under the action of the arrester, and it is difficult to cause the trip of the grounding line.

I. Introduction

The 110 kV transmission line passing the mountain areas is prone to severe icing on the conductors and overhead ground wires in winter as a result of micro landform and climate. While severe icing of the overhead ground wire will increase the sagging of the ground wire, causing the discharge of the phase wire to the ground wire and probably a disconnection accident. In order to improve the anti-icing performance of the line and maintain the normal operation of the line, it is a feasible measure to eliminate the overhead ground wire to reduce the icing accident[1]. The cancellation of the ground wire not only avoids accidents such as the breaking of the overhead ground wire caused by icing, but also reduces the line cost in the project and facilitates the project installation to a certain extent. After the overhead ground wire is canceled, the entire line loses the protection against lightning strikes, and the reduction of the lightning resistance strength of the line leads to an increase in the lightning strike trip rate[2]. Therefore, the researchers proposed to install composite arrester combined insulators with lightning protection function on the transmission line to improve the lightning resistance performance of the line without ground wire[3].