Research On Transmission Line Shielding Failure Trip-Out Rate Influenced By Terrain Parameters And Lightning Activity Characteristics

Currently, Lightning shielding failure is the main reason that endangers the safety and reliability of EHV/UHV transmission line.However, transmission line corridor through the wilderness, hills, mountains and other complex terrain, The lighting shielding failure performance are influenced by the terrain.at the same time,lightning location system has been running for many years and accumulated vast amounts of data, so it is necessary to research lightning parameter features and terrain parameters affecting on shielding failure performance.The lighting shielding failure performance are influenced by the terrain,and changing of ground wires and conductor. In this paper, the method of getting the micro-topography and the relative position between the wire, ground wire and ground is proposed, and then combined with electrical geometry model to cauclate shielding failure trip out rate. First of all, the transmission line coordinate were divide into many similar segment, using Google Earth software to obtain the altitude of every point and obtain the ground elevation; secondly, according the characteristics of lead and the altitude of every point to obtain the relative position between ground wire,conductor wire and the ground; Lastly,based on electrical geometry model, calculating the shielding failure trip out rate of each segment and tower. Take a 500kV transmission line as an example, analysis of topographic effects on maximum shielding failure lighting current. And the changing of the shielding failure trip out rate along the span.The lighting shielding failure performance is influenced by the lighting parameter characteristics. The method of dividing statistical regional of transmission line corridor is proposed. Statistical area is a span length on the direction of transmission corridor, and for a certain distance to the vertical direction of transmission corridor and the tower of the span end (the distance is more than equal to the lightning location system accuracy). Based on the lightning location system data from 1999 to 2008,using geographic information system software to statistic the lightning parameters of Huizhou region and NengBo transmission line. And then take the NengBo transmission line as an example, analysis of lighting parameter effects on shielding performance.Taking the NengBo transmission line as an example, calculating the lightning shielding failure trip rate on the actual topography and lighting parameters. It can find the towers which easy to be suffered lightning stroke in the entire transmission line. Compared the operation data that the actual lightning strikes occurred in the easy stroke interzone, this proposed method has a better agreement.