VFTO对电子电压互感器的传导干扰分析及其抑制措施研究

Analysis of Conducted Interference and Research of its Suppression Measures for VFTO on Electronic Voltage Transformer

以空气绝缘变电站隔离开关操作为干扰源对象,建立电容分压型互感器传感单元等效电路,分析电容分压型互感器传感单元自身参数对分压比频率特性的影响,并结合隔离开关分合容性小电流仿真电路研究特快速暂态过电压传导干扰下互感器传感单元的输出电压。通过仿真分析避雷器、阻波器及双RC滤波和瞬变抑制二极管组合防护电路的抑制作用,结果表明避雷器对空气绝缘变电站隔离开关操作产生的特快速暂态过电压抑制效果并不理想,甚至会使峰值升高;阻波器能有效抑制特快速暂态过电压中的高频分量;双RC滤波和瞬变抑制二极管组合防护电路不仅将传感单元的输出电压限制在了允许范围内,还滤除了其中的高频分量。

In this paper,the equivalent circuit of the capacitive divider transformer sensing unit is established by taking the air insulated substations(AIS)disconnector operation as the interference source object,the influence of the parameters of the capacitive divider transformer sensing unit on the frequency characteristics of the voltage division ratio is analyzed,and the output voltage of the transformer sensing unit under very fast transient overvoltage(VFTO)conduction interference is studied by combining the disconnector disintegration capacitive small current simulation circuit.Trough the simulation the suppression effect of the arrester,the wave blocker,the dual RC filter and transient voltage suppressor(TVS)tube combination protection circuit is analyzed.The results show that the suppression effect of the arrester on the VFTO generated by AIS disconnector operation is not ideal,and even the peak value will increase.The wave blocker can effectively suppress the high-frequency component in the VFTO.The dual RC filter and TVS tube combination protection circuit not only limits the output voltage of the sensing unit to the allowable range,but also filters out the high-frequency components in it.