杂散电容对交流滤波器用避雷器电气应力计算的影响分析

Influence Analysis of Stray Capacitance on Stress Calculation of AC Filter Arrester

交流滤波器是直流输电系统的重要组成部分,其各部分准确的电气应力,即过电压、电流和吸收能量仿真计算是绝缘设计及安全稳定运行的基础,为此提出杂散电容对交流滤波器用避雷器电气应力计算的影响分析方法。首先基于三维有限元仿真软件和PSCAD电磁暂态仿真程序,建立交流滤波器各设备间的杂散电容计算模型和电磁暂态仿真计算模型;然后对比分析杂散电容对滤波器投入及接地故障工况下的各小组滤波器的避雷器电压、电流及吸收能量的影响。仿真结果表明:考虑滤波器设备间的杂散电容后,避雷器电压幅值增加2.1%~9.6%,电流幅值增加5.7%~162.5%,能量增加2.4%~281.8%,但绝对值增加不明显;因此涉及避雷器精确计算的场合中可以充分考虑杂散电容的影响,但在避雷器绝缘裕度较大的设计场合,为了降低计算难度也可以忽略杂散电容。

The AC filter is an important part of HVDC system,and the accurate simulation calculation of its electrical transient stress including overvoltage,current and absorbed energy is the basis of insulation design and safe and stable operation.This paper proposes a method of analyzing the influence of stray capacitance on the electrical stress of the AC filter arrester.It firstly establishes the stray capacitance calculation model and electromagnetic transient simulation model of the AC filter equipment based on the three-dimensional finite element simulation software and PSCAD electromagnetic transient simulation program.Then,it compares and analyzes influences of the stray capacitance on the voltage,current and absorbed energy of the arrester of each filter group under the conditions of filter input and the grounding fault.The simulation results show that after considering the stray capacitance between the filter devices,the voltage amplitude of the arrester increases by 2.1%~9.6%,the current amplitude increases by 5.7%~162.5%,and the energy increases by 2.4%~281.8%,but the absolute values do not increase obviously.Therefore,the influence of stray capacitance can be fully considered in the case of accurate calculation of the arrester,but in the design of large insulation margin,the stray capacitance can be ignored in order to reduce the calculation difficulty.