架空输电线路雷电过电压的瞬态特性研究

发布时间：2019-04-02 17:12

【摘要】：随着我国工业经济的不断发展，电力系统超高压电网也在不断提高和改进，特别是超高压输电线路的高度、传输距离等都在不断提高。我国幅员辽阔，有着复杂多样的地形地貌，高压架空输电线路在旷野中经受到各种各样的考验。雷击故障时有发生，对我国超高压电网的运行造成威胁。近年来，，随着同塔双回输电线路这种输电方式的广泛应用，其设计、制造、施工和运行已经非常成熟，但是，由雷击输电线路造成的电网事故仍然不断发生。为了制定更有效的防雷对策，减少雷击事故的发生，需要更准确的研究分析雷击输电线路的雷电过电压的瞬态特性。通过仿真模拟，探索其规律，可以对新线路的防雷设计提供有价值的参考，并且对提高现有输电线路雷电防护水平有着深远的意义和工程实用价值。本文根据输电线路雷电反击过电压和雷电绕击过电压的产生机理，利用电磁暂态仿真程序PSCAD/EMTDC对500kV超高压同塔双回输电线路的雷电过电压的瞬态特性进行了仿真分析。输电线路雷击仿真模型的建立包括雷电流模型、输电线路模型、杆塔模型、绝缘子闪络模型以及避雷器模型，基于PSCAD/EMTDC雷电仿真模型分别对雷电反击故障和雷电绕击故障产生的雷电过电压的瞬态特性进行了分析，研究了影响同塔双回输电线路反击过电压和绕击过电压的影响因素，并重点分析了加装线路避雷器、不平衡绝缘的防雷措施对提高输电线路耐雷水平的效果。最后根据某省500kV超高压输电线路的实际工况，对其近年来的雷击跳闸事故进行了统计分析，并针对特定的反击和绕击故障进行了仿真模拟，提出有效的防雷策略。本文的研究成果对500kV超高压输电线路雷电过电压的研究及同塔双回输电线路的防雷策略研究提供了有价值的参考。
[Abstract]:With the continuous development of our country's industrial economy, the ultra-high voltage power grid of power system is also continuously improved and improved, especially the height and transmission distance of ultra-high voltage transmission lines are constantly increasing. China has a vast territory and various landforms. High-voltage overhead transmission lines have been tested in the wilderness. Lightning strikes occur frequently, which threaten the operation of ultra-high voltage power grid in China. In recent years, with the wide application of double-circuit transmission line with the same tower, its design, manufacture, construction and operation have been very mature. However, the power network accidents caused by lightning strike transmission line are still occurring. In order to make more effective anti-lightning countermeasures and reduce the occurrence of lightning strike accidents, it is necessary to study and analyze the transient characteristics of lightning over-voltage of lightning-struck transmission lines more accurately. It can provide valuable reference for lightning protection design of new transmission lines through simulation and explore its regularity, and has far-reaching significance and practical value in engineering for improving lightning protection level of existing transmission lines. According to the generation mechanism of lightning over-voltage and lightning bypass overvoltage of transmission line, the transient characteristics of lightning over-voltage of 500kV ultra-high voltage and double-circuit transmission line with tower are simulated and analyzed by using electromagnetic transient simulation program PSCAD/EMTDC. The simulation model of lightning strike of transmission line includes lightning current model, transmission line model, tower model, insulator flashover model and lightning arrester model. Based on the PSCAD/EMTDC lightning simulation model, the transient characteristics of lightning overvoltage caused by lightning backlash fault and lightning bypass fault are analyzed, and the factors affecting the return back overvoltage and bypass overvoltage of the same tower double-circuit transmission line are studied. The lightning protection effect of installing line lightning arrester and unbalanced insulation to improve the lightning resistance level of transmission line is analyzed in detail. Finally, according to the actual conditions of 500kV EHV transmission lines in a province, the lightning tripping accidents in recent years are statistically analyzed, and the simulation of specific counter-attack and bypass faults is carried out, and an effective lightning protection strategy is put forward. The research results of this paper provide a valuable reference for the study of lightning overvoltage of 500 kV ultra-high voltage transmission line and the study of lightning protection strategy of double-circuit transmission line with the same tower.
【学位授予单位】：华北电力大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM863

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