VFTO的全时段仿真与实测对比研究

Comparative study of full-time simulation and measurement of VFTO

隔离开关操作过程中,动静触头两端距离的变化会导致二者之间的介质被击穿,产生电弧放电现象。随着开关动作的持续电弧的状态在燃弧和熄弧之间反复交替,产生重燃现象,而电弧的反复重燃会在回路中产生特快速暂态过电压(Very Fast Transient Overvoltage,VFTO)。为了研究实际情况下电弧的反复重燃过程,在以往研究的单次燃弧基础上,弄清多次燃弧过程的电弧电压的变化规律。文章对VFTO的典型波形进行了理论分析,并在优化基于逻辑判断的电弧重燃仿真模型的基础上将仿真数据与实际现场测得的VFTO数据进行对比,验证了该电弧全时段仿真模型的正确性。研究发现电弧多次重燃导致VFTO的电压波形发展趋势类似“台阶”状,未考虑残余电荷影响时过电压幅值最大约为1.7 p.u.,单次燃弧持续最长时间约为8 ms,整体振荡衰减波过程的频率约为0.5 MHz,超高频频率约为25 MHz,高频频率约为6.5 MHz。

During the operation of the isolating switch,the switching gap may cause arcing due to the breakdown of the medium because of the voltage difference,and the circuit may generate a very fast transient overvoltage(VFTO)due to multiple re-ignition of the switching arc.In order to study the repeated re-ignition process of the arc under actual conditions,based on the single-arc burning of the previous study,the variation law of the arc voltage in the multiple-arcing process was clarified.In this paper,we analyzed the typical waveform of VFTO theoretically,and based on optimizing simulation model of the arc re-ignition with the logical judgment,comparing the simulation data with the VFTO data measured in the field,which validates the correctness of the full-time arc simulation model.The simulation results are consistent with the previous theoretical calculations and single arc simulation results.Finally,comparing the arc arcing data measured in the actual field to verify the correctness of the arc full-band simulation model.We found that the voltage development waveform of the re-ignition of the arc is similar to the"step"shape.The maximum overvoltage amplitude is about 1.7 p.u.,the duration of single arc is about 8ms,the frequency of the whole oscillation attenuation process is about 0.5 MHz,the ultra-high frequency is about 25 MHz,and the high frequency is about 6.5 MHz.