Abstract
Windage yaw flashovers under strong wind and rain conditions leave a negative impact on the safe operation of transmission lines. However, the mechanism behind this is not well known yet. Therefore, this paper proposes a systematic method, including three basic parts described as simulation of wind and rain loads, calculation of windage yaw, and flashover analysis, to analyze windage yaw flashovers of transmission lines. The YanMeng-particle swarm optimization (YanMeng-PSO) algorithm is proposed to enhance the simulation accuracy. Unlike the conventional approach, the windage yaw status of conductors and insulator strings is dynamically described with key nodes and the breakdown voltage of their clearances rather than windage yaw angle. Furthermore, in the second part, a new method named key-node method (KNM) is proposed to calculate the conductors’ windage yaw. Moreover, the rain effect is also considered in this paper. This paper then presents a case study on a 110 kV double-circuit transmission line section that suffered severe collapse when the typhoon Rammasun landed in Hainan island. Particular focus was placed on the windage yaw flashover before the structural failure of the transmission line. The results validated the significant rain effect and found that conductors/ground suffer more severe windage yaw flashover than insulator strings. Finally, constructive solutions such as interphase spacers, reasonable conductor arrangement in the design phase, and regular measurements and adjustments of conductor sag in the maintenance phase are proposed to improve the design of transmission lines to enhance their capacity against windage yaw flashovers.
Highlights
Windage yaw flashovers due to extreme wind and rain conditions under typhoon weather greatly threaten the stability of transmission lines, especially for the coastal area with an average of nine typhoons landing [1]
With the wind and rain loads applying on insulator strings and conductors, the conductor suspension points get close to the tower applying strings andmay conductors, conductor suspensionifpoints get close the tower body and on theinsulator cross-arm, which lead to the flashover phenomenon the spacing is to reduced to body and the cross-arm, which may lead to flashover phenomenon if the spacing is reduced to below below the permissible value for the certain voltage level
This paper proposes a systematic method to conduct the analysis of transmission line windage
Summary
Windage yaw flashovers due to extreme wind and rain conditions under typhoon weather greatly threaten the stability of transmission lines, especially for the coastal area with an average of nine typhoons landing [1]. About 29.42% of trippings were ascertained to be caused by towers collapses and strand fractures, while 59 trippings accounted for approximately 50.43% of the total due to unknown reasons, which were likely to be windage yaw flashovers. To reduce the losses caused by strong wind and rain conditions under typhoon and ensure the stability of transmission lines, it is of great significance to study the mechanisms of windage yaw flashovers.
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