550 kV GIS变电站中VFTO仿真计算及抑制措施

Numerical Simulation and Suppression Measure for VFTO in 550 kV GIS Substation

在气体绝缘变电站GIS(gas insulated substation)中,隔离开关进行分合母线时引起的特快速暂态过电压VFTO(very fast transient overvoltage)威胁站内设备安全,深入认识VFTO的特点并提出适当的抑制措施对于保障GIS变电站的安全具有重要意义。选取深圳某550 kV GIS变电站为研究对象,采用电磁暂态程序EMTP/ATP(electro-magnetic transient program/alternative transient program)仿真研究了隔离开关切合母线时产生的VFTO过程及特点,分析了变压器入口电容和主变进线长度对VFTO波形、幅值和频率的影响,提出了采用阻波器和铁氧体磁环抑制VFTO的方法。结果表明:随着变压器入口电容的增大,VFTO的幅值增大;随着主变进线长度的增加,VFTO的频率降低。阻波器比铁氧体磁环具有更好的VFTO抑制效果。所得结论对GIS变电站中的VFTO防控具有参考价值。

In a gas insulated substation(GIS),the very fast transient overvoltage(VFTO)caused by opening and clos⁃ing the isolating switch of a busbar threatens the safety of the equipment in the station.Therefore,it is of significance for ensuring the safety of the GIS substation through understanding the characteristics of VFTO and further proposing ap⁃propriate suppression measures.In this paper,a 550 kV GIS substation in Shenzhen is taken as the research object,and electro-magnetic transient program/alternative transient program(EMTP/ATP)is used to simulate the VFTO gener⁃ation process and its characteristics as the isolating switch is connected to the busbar.The influences of transformer in⁃let capacitance and the length of transformer incoming line on the VFTO waveform,amplitude and frequency are ana⁃lyzed,and the methods for suppressing VFTO by means of a wave trap and ferrite magnetic ring are proposed.Results show that with the increase in transformer inlet capacitance,the amplitude of VFTO increases.When the length of the transformer incoming line increases,the frequency of VFTO decreases.Moreover,the wave trap has a better VFTO sup⁃pression effect than the ferrite magnetic ring.The conclusions drawn from this paper are helpful for the prevention and control of VFTO in GIS substations.