特高压变电站电磁暂态过电压机理与控制

王磊 王浩 王珏 马国明 王东举

摘 要：根据研究的总体目标及研究思路和任务，该研究总结归纳出重点需关注的科学问题：（1）VFTO机理及建模仿真；（2）VFTO作用下GIS破坏机理和绝缘特性。针对此科学问题的主要研究内容包括： 基于所研制的T型电极VFTO传感器在特高压变电站开展了特快速暂态过电压的实测研究，获得了大量宝贵实测数据。为特高压变电站隔离开关带电操作决策及变电站设计提供了支撑。研究提出并实践了从“SF6小间隙（间隙距离为mm级）-SF6大间隙（间隙距离为cm级）-GIS隔离开关”的系统技术路线，有效克服GIS隔离开关中VFTO高频振荡电弧难以观测的技术难题，得到了特高压GIS隔离开关的全过程时变弧阻模型。研究获得了大尺度GIS部件的VFTO绝缘特性，获得了与雷电绝缘特性的等价关系，给出了波形转换系数1.1，为VFTO绝缘配合难题的解决提供了重要支撑。建立两路纳秒级脉冲群VFTO模拟电源及其配套的绝缘试验腔和测试系统，测试系统包括紫外光谱测试仪、高能电子测试装置。模拟VFTO波形，开展纳秒脉冲下SF6气体的击穿和闪络特性实验，获得不同气体压力下SF6气体的击穿和闪络规律和特性；发现在一定压力条件下，极不均匀场下SF6击穿的极性效应出现反转现象；基于记忆效应提出重复纳秒脉冲下的放电机理。在252 kV GIS试验回路上，开展了铁氧体磁环串抑制VFTO的系列试验，研究了不同试验电压下VFTO波形的主要特征参数与磁环串长度的关系，证实了铁氧体磁环串对VFTO的幅值和陡度均有显著的抑制效果。

关键词：特高压 特快速瞬态过电压 绝缘特性

The Mechanism and Control of Electromagnetic Transient Overvoltage in UHV GIS Substation

Wang Lei1 Wang Hao1 Wang Jue2 Ma Guoming3 Wang Dongju4

（1.China Electric Power Research Institute；2.Institute of Electrical Engineering，Chinese Academy of Sciences；3.North China Electric Power University；4.Zhejiang University）

Abstract：According to the goals，thoughts and tasks of 973 Program，two scientific problems are summarized in this topic：（1）Mechanisms，modeling and simulations of VFTO；（2）failure mechanisms and insulation characteristics of GIS stressed by VFTO.The main content of the topic focus on the scientific problems above is：Basic research is a driving force for the progress of human civilization，a source and backbone of S&T and economic development，VFTO measurement have been carried out in UHV substations based on the developed T-type VFTO sensor， the experiment results is valuable to support the decision about the disconnector switching operation and the design of the UHV substation.A creative technical route is studied and proposed， namely ‘small-scale SF6 gap （gap distance in mm grade）- large-scale SF6 gap （gap distance of cm-level） isolating distance of the GIS disconnector， which can effectively overcome the technical problems in observing arc with interference by high-frequency oscillation of VFTO， and a variable arc resistance model during the whole operating process of UHV GIS disconnector is obtained. In addition， research are carried out to get the insulating properties oh large-scale GIS components under VFTO， the equivalence relations between VFTO and LIWV （i.e. lightning impulse withstand voltage） is achieved and the waveform conversion factor 1.1 is put forward， which provides important support for solving insulation coordination problem. The multi-VFTO analog power， test chamber and the measuring system that included ultraviolet spectral tester and high energy electronic test device had been built. The breakdown and flashover characteristics experiment under simulation of VFTO pulse in SF6 gas was carried out. The regularity and characteristics of breakdown and flashover under different gas pressure in SF6 is given. The experinmental results shows in certain pressure conditions， the breakdown regularity of the SF6 under extremely uneven was different with DC， AC and other long pulse， the positive impulse breakdown voltage is greater than the negative pulse.The repetitive pulse discharge mechanism was obtained based on the memory effect. Series tests were carried on the 252kV GIS test circuit to research the relationship between the main parameters of the VFTO waveform and the length of the magnetic ring cluster. It is confirmed that the ferrite magnetic rings have notable suppression effects to the amplitude and steepness of the VFTO.

Key Words：Ultra High Voltage；Very Fast Transient Overvoltage；Insulation characteristic

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