输电线路杆塔接地系统冲击散流特性及影响因素研究

发布时间：2018-06-01 10:08

本文选题：CDEGS + 接地系统　；参考：《西南交通大学》2014年硕士论文

【摘要】：电力系统运行经验表明,接地技术对电力系统的安全稳定运行有着重要的影响。我国电网正朝着更大规模、更高功率、更加智能的方向发展,这些发展对现阶段电网可靠、安全、有效的运行提出了更高的挑战,输电线路杆塔接地极的冲击接地电阻直接影响输电线路的防雷保护效果,而输电线路杆塔的防雷性能与接地系统的冲击散流特性密切相关。本文主要研究输电线路杆塔接地系统的冲击散流特性,分析接地系统冲击散流特性的影响因素及影响规律,为实际工程中接地系统设计提供技术支持。首先本文综述了输电线路杆塔及其接地系统冲击特性的研究现状,随后介绍了几种典型的输电杆塔仿真模型,分析了现有接地系统暂态计算模型、试验方法及应用范围。计算了典型雷电波频谱,探明冲击电流下接地极的散流机理及土壤电阻率对接地极冲击散流的影响规律。其次采用电磁仿真软件CDEGS搭建输电线路杆塔接地系统雷电冲击散流模型,研究接地系统冲击散流的影响因素,发现随着雷电流波前时间变长、杆塔高度降低、横担宽度变大、土壤电阻率降低、接地极长度增长,塔顶及接地极冲击电压峰值降低,随着雷电流半波时间变长、土壤电阻率上升、输电杆塔档距减小,避雷线分流增加,被击杆塔分流减少。最后采用ATP-EMTP建立考虑火花放电的接地极分布参数电路模型,计算模型中电气参数以及接地导体间互感大小。基于该模型分析了单根水平接地极、两两平行接地极和Y型接地极的冲击暂态响应。建立冲击试验平台,对水平接地极进行了冲击放电试验,通过分析试验结果和仿真结果揭示火花放电下接地极的冲击散流特性。
[Abstract]:The operation experience of power system shows that grounding technology has an important influence on the safe and stable operation of power system. The power grid of our country is developing towards the direction of larger scale, higher power and more intelligence. These developments pose a higher challenge to the reliable, safe and effective operation of the power grid at this stage. The impact grounding resistance of the earth pole of the transmission line tower directly affects the lightning protection effect of the transmission line, while the lightning protection performance of the transmission line tower is closely related to the impact and dispersion characteristics of the grounding system. In this paper, the characteristics of shock current in grounding system of transmission line tower are studied, and the influencing factors and rules of impact current characteristics of grounding system are analyzed in order to provide technical support for the design of grounding system in practical engineering. In this paper, the current situation of research on the impact characteristics of transmission line tower and its grounding system is summarized, then several typical simulation models of transmission tower are introduced, and the existing transient calculation model, test method and application range of grounding system are analyzed. The spectrum of typical lightning wave is calculated, and the mechanism of earth pole dispersion under impulse current and the influence of soil resistivity on the impact current of the earth pole are investigated. Secondly, the electromagnetic simulation software CDEGS is used to build the lightning shock current model of the transmission line tower grounding system, and the influence factors of the impact scattering current of the grounding system are studied. It is found that with the increase of the lightning current wave front time, the height of the pole tower decreases, and the width of the cross pole becomes larger. The soil resistivity decreases, the earth pole length increases, and the peak impulse voltage of tower top and earth pole decreases. With the increase of lightning current half-wave time, the soil resistivity increases, the distance of transmission tower decreases, the distribution of lightning arrester increases, and the shunt of struck tower decreases. Finally, ATP-EMTP is used to set up the circuit model of earth pole distribution parameters considering spark discharge. The electrical parameters and the mutual inductance between grounding conductors are calculated in the model. Based on the model, the impulse transient response of single horizontal earth pole, parallel ground pole and Y type earth pole is analyzed. An impact test platform was established to test the impact discharge of the horizontal ground electrode. The characteristics of the impact dispersion of the ground electrode under spark discharge were revealed by analyzing the test results and the simulation results.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM75;TM862

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