GIS局部放电检测机理与精确定位研究

发布时间：2018-03-08 17:15

本文选题：局部放电　切入点：传播特性　出处：《中国矿业大学》2017年博士论文　论文类型：学位论文

【摘要】：气体绝缘组合电器(Gas Insulated Switchgear,GIS)是一种封闭的新型绝缘电气装置,由于拥有结构紧凑、体积较小、技术指标优越且基本不受外界影响等优点,已经广泛地应用在国内外电力系统当中。但随着GIS的应用的快速增长以及运行时间的推移,GIS设备不同程度地出现了各种故障。当GIS内部存在绝缘缺陷时,可能会引起局部放电。而长期局部放电会使绝缘性能进一步劣化,最终导致绝缘击穿。同时,GIS的局部放电检测存在手段繁多,精度不高等问题。本文以GIS内部的典型绝缘缺陷为对象进行了仿真研究,探究GIS内部电磁波信号的传播特性。针对双端局部放电定位方法中的时间同步准确度而引起的定位不准确问题,根据GIS同轴波导的电磁波特点,以传统特高频检测法为基础,研究采用多个检测点同步进行局部放电定位的检测点布置方案,实现特高频传感器的合理布置。在此基础上,研究基于多个测量点的局部放电精确定位方法,利用实验证明了所提方法的正确性和可行性。本文对GIS局部放电的检测机理进行了研究。利用仿真软件,首先仿真带金属法兰和金属屏蔽环的盆式绝缘子附近场强分布情况。重点研究导体和筒壁上金属尖刺、自由金属微粒、绝缘子表面污秽和盆式绝缘子内部气隙等不同缺陷情况下的GIS内部电场强度分布特点,并对带有绝缘缺陷的GIS内部电场进行数值仿真计算。研究发现,内部气隙对内部场强的畸变更严重;金属微粒靠近高压导体时,金属微粒表面的电场强度最大;绝缘子表面污秽仅仅对绝缘子表面的电场产生较大的畸变效应;针尖部位对电场的畸变最为严重。电磁波的传播特性是GIS特高频定位方法的核心。通过仿真分析局部放电产生的特高频电磁波在GIS典型结构中传播特性,包括电磁波信号与局部放电源的关系特性、电磁波信号与检测点角度之间的关系特性及电磁波信号经过GIS的T型节点和L型节点后的衰减特性。研究发现,最佳的检测角度与放电位置呈0°或180°,在内部空间位置上,检测点在顶部或者底部效果最佳,电磁波信号经过GIS各不连续部件,如绝缘子、L型转角、T型转角时均会产生明显衰减。本文在局部放电定位的基本原理上,将GIS空间结构抽象成无向图,以电磁波一定以最短路径到达测量点的特征为基础,提出了电磁波传播临界点的概念。并且,以最优经济性为优化目标,最大可观性为约束条件,建立0-1规划模型,求解得到采用多个检测点同步进行局部放电定位的测量点布置方案。以电磁波的衰减特性为依据,进一步提出高测量可靠性的测量点布置优化模型,并得到布置方案。算例证明,所提方案能够满足最大可观性,且具有更高的可靠性。在最优配置下,同步获取局部放电产生的电磁波初始波头到达各传感器的时间后,利用扩展时差定位法,融合各传感器的波头信息及GIS固有拓扑结构,引用Euclidean距离得到初步测距结果,进而求得对应的局放发生时间,最后利用此局放时间进一步提高了测距精度。经仿真验证,相比于普通双端时差定位方法,该方法通过局放发生时间对测距结果的修正得到了较高的测距精度,证明了算法的有效性和准确性。
[Abstract]:Gas insulated switchgear (Gas Insulated Switchgear, GIS) is a new type of electrical insulation device is closed, because of its compact structure, small volume, excellent index and basic technology is not influenced by the outside world and other advantages, has been widely used in power system at home and abroad. But with the rapid growth of GIS applications and the running time over time, GIS equipment, different degrees of the various fault. When GIS the internal insulation defects, may cause partial discharge. And the long-term partial discharge will make further deterioration of insulation, resulting in insulation breakdown. At the same time, partial discharge detection in the presence of GIS means many, accuracy is not high. The typical GIS the internal insulation defects are simulated as the object, the propagation characteristics of GIS on internal electromagnetic wave signals. Aiming at the double partial discharge location method of time synchronization accuracy and Due to the inaccurate positioning, according to the electromagnetic characteristics of GIS coaxial waveguide, the traditional UHF detection method based on the detection point layout scheme of synchronous multiple partial discharge location detection point, realize the reasonable arrangement of UHF sensor. On this basis, the method of partial discharge of accurate positioning of a plurality of measuring points based on the correctness and feasibility of the proposed method was verified by experiment. The detection mechanism of GIS partial discharge are studied. By using the simulation software of electric field distribution near the insulator metal flange and the metal shielding ring the first simulation. Focus on the conductor and the tube wall metal spikes, free metal particles. Insulators and insulator inside the gap of different defects in the case of GIS internal electric field intensity distribution characteristics, and with insulation defects inside GIS electric field The numerical simulation calculation. The study found that the internal gas of the internal field distortion is serious; the metal particles near the high voltage conductor, the surface of metal particles and the maximum electric field intensity; insulator surfaces only on insulator surface electric field distortion effect is bigger; the needle tip of the electric field distortion is the most serious. The propagation characteristic of electromagnetic wave is the core of GIS UHF localization method. Through the simulation analysis of the propagation characteristics of UHF electromagnetic wave generated by partial discharge in GIS typical structure, including the relationship between the characteristics of electromagnetic wave signal and the PD source, the relationship between characteristics and electromagnetic wave signals between electromagnetic wave signal and the detection point of view through the attenuation characteristics of T type and L type node node GIS. After the study found that the angle and the discharge position is 0 degrees or 180 degrees to detect the best position in space on the inside, the best point in the detection of the top or bottom of the electromagnetic effect The continuous wave signal after GIS components, such as insulators, L angle, T angle will produce obvious attenuation. In this paper, the basic principle of partial discharge location on the GIS space structure is abstracted into undirected graph, the electromagnetic wave in the shortest path to reach the characteristics of measuring points as the basis, put forward the concept of electromagnetic wave propagation. The critical point and the optimal economy as the optimization objectives, the maximum observable, the establishment of 0-1 programming model is obtained by measuring point arrangement scheme for partial discharge location multiple detection points. The attenuation characteristics of electromagnetic wave as the basis, further puts forward the optimization model of the measuring point the layout of the high measurement reliability, and layout scheme. Numerical examples show that the proposed scheme can meet the maximum observability, and has higher reliability. In the optimal configuration, synchronous access to local discharge of electric magnetic wave initial wave The first time to each sensor, using the extended TDOA location method, the fusion of sensor head wave information and inherent GIS topology, reference Euclidean distance of initial ranging results, and then obtain the corresponding partial discharge time, by this time PD further improve ranging accuracy. The simulation results show that compared to ordinary double end location method, the method of using PD occurring time correction of the ranging results are high accuracy, proved the validity and accuracy of the algorithm.

【学位授予单位】：中国矿业大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TM595

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