【作者】 杜巍；

【导师】 刘教民；

【作者基本信息】 华北电力大学 ， 电机与电器， 2014， 博士

【摘要】 在特高压电网中,封闭式气体绝缘组合电器(GIS)中隔离开关操作产生的特快速暂态过电压(VFTO)会危及电气设备的绝缘安全。数值仿真是获得VFTO波形及研究其特性的重要方法,本文针对当前VFTO仿真分析中传输线残余电荷电压的处理,多次击穿全过程波形仿真和隔离开关电弧阻抗模型及参数选取等几个关键问题进行了深入地分析和研究。本文主要工作和研究成果如下：1.提出了基于时域有限元的VFTO单次击穿波形仿真计算方法。与传统的EMTP仿真方法相比,该方法不但可以有效计及残余电荷电压在传输线上的分布特性,而且还可以计算沿传输线任意点的离散电压值和电流值。采用该方法和EMTP方法对VFTO单次击穿波形进行了仿真计算,通过对两种方法下VFTO的仿真结果进行对比分析,论证了本文方法的有效性及优势。2.提出了用于VFTO多次击穿波形仿真分析的计算方法。该方法可以有效考虑隔离开关操作速度、空载母线残余电荷电压等对VFTO全过程多次击穿波形的影响。采用该方法对一种常见情况下的VFTO多次击穿波形进行了仿真计算,获得了击穿次数,击穿时刻等VFTO多次击穿波形特性。3.对现有隔离开关电弧阻抗模型进行了对比分析,提取了击穿延时、燃弧电阻、熄弧阻抗模型、熄弧时间、电弧电感和断口电容等不便测量的关键电弧参数,为研究电弧阻抗模型和参数选取对VFTO仿真结果的影响规律奠定基础。4.研究了隔离开关电弧阻抗模型及参数选取对VFTO仿真结果的影响规律。研究结果表明,击穿延时会影响VFTO的陡度,稳态燃弧电阻会影响VFTO的幅值,熄弧时间会影响VFTO的衰减速度,断口电容和燃弧电感会影响VFTO的最大幅值及波形走势。本文所做的课题获得了河北省自然科学基金(VFTO仿真用多次重燃GIS隔离开关电弧模型的研究E2012208006)的资助。更多还原

【Abstract】 Very fast transient over-voltage (VFTO) is produced when the disconnector operates in gas insulated switchgear (GIS), which may endanger the safety of the insulation of GIS equipment in ultra-high voltage(UHV) grid. The simulation technology is a important research method for obtaining VFTO waveforms and studying the characteristics of VFTO. In this dissertation, several key problems in VFTO simulation analysis such as modeling residual charge voltage on transmission lines, the simulation for repeated-breakdown VFTO waveforms and arc impedance model, are carried out to be analyzed and studied deeply. The principal content and achievements of this dissertation is listed as following:1. A novel simulation calculation method for single-breakdown VFTO waveforms based on time domain finite element method (TDFEM) is presented. Compared with the traditional electro-magnetic transient program (EMTP), this method not only can take the distribution characteristic of the residual charge voltage of the transmission line into account effectively, but also can calculate the discrete voltage and current values at any point along the transmission line. The simulation of single-breakdown VFTO waveforms is carried out by TDFEM and EMTP. The detailed comparative analysis is conducted on simulation results, demonstrating the effectiveness and superiority of TDFEM.2. A simulation calculation method for repeated-breakdown VFTO waveforms is presented. In this method, the influence of operating speed of disconnectors and residual charge voltage on repeated-breakdown VFTO waveforms is taken into consideration. The simulation of repeated-breakdown VFTO waveforms under a common situation is carried out by the proposed method. The characteristics of repeated-breakdown VFTO waveforms such as the times of breakdown, breakdown time, etc is obtained.3. The detailed comparative analysis is conducted on the arc impedance models of disconnector. The key arc parameters, which are inconvenience for measurement, such as breakdown delay, arcing resistance, arc resistance model, extinction time, the arc inductance and capacitance fracture, are obtained, laying the foundation for the research of the influence of the arc impedance model and its parameter of disconnector on VFTO. 4. The influence of the arc impedance model and its parameter of disconnector on VFTO is studied. The simulation results show that gas breakdown process has a great effect on VFTO gradient, steady state arc resistance influences VFTO amplitude and the quenching process of arc affects VFTO attenuation speed. Arc inductance and fracture capacitance can affect the maximum amplitude of VFTO and the waveforms trend.The subject of this dissertation received Natural Science Foundation of Hebei Province (Reaearch on Simulation Disconnect Switch Model for VFTO with Multi-Restrike E2012208006).更多还原