套管故障对变压器频响曲线影响的仿真研究  

Simulation Study of Influence of Transformer Bushing Fault on Frequency Response Curves

作　　者：刘勇[1] 崔彦捷 秦睿[2] 汲胜昌[1] 梁笑尘[1] 朱生鸿[2] 

机构地区：[1]西安交通大学电力设备电气绝缘国家重点实验室,西安710049 [2]甘肃电力科学研究院,兰州730050

出　　处：《高电压技术》2014年第8期2406-2415,共10页High Voltage Engineering

基　　金：国家电网公司科技项目(522722130397)~~

摘　　要：用频响法在线或离线进行变压器绕组变形检测时,套管状态对频响曲线的影响往往被忽略,不仅不利于绕组故障的判定,且容易造成事故隐患。为此,建立了一种新型变压器等效电路模型,利用软件仿真和数值计算相结合的方法得到了该模型的各项参数,并以频率响应分析法(FRA)为理论基础,通过在线和离线的方式,仿真研究了套管出现阻性、容性、阻/容性故障时变压器频响曲线的变化情况。结果表明:在频率为1 kHz^1 MHz时,变压器离线测试对套管阻性、容性、阻/容性故障并不敏感,基本不会造成频响曲线的改变和绕组的误判;而在线测试时,套管的容性和阻/容性故障皆会造成频响曲线的改变,且在整个频段中套管电容的大小与频响曲线的幅值高低呈正相关,该现象在频率为10~40 kHz时最为明显,根据相关系数会误判为变压器绕组变形;但套管阻性故障并不影响在线测试频响曲线的走势,从而确定了造成在线测试变压器频响曲线变化的主要原因为套管电容因素。For both online and offiine detection of transformers winding deformation using the frequency response analysis （FRA） method, the influence of bushing condition on frequency response curves is generally ignored, which may mislead the fault diagnosis or even cause accidents. Thus, we developed an equivalent circuit model of transformer based on the FRA method. The distribution parameters of the model were obtained by combining simulation in ANSYS and some mathematical methods. Moreover, we researched the variation of the online and offiine frequency response curves of the transformer under capacitive, resistive, and resistance-capacitive bushing faults, respectively. The simulation results show that, within 1 kHz-1 MHz, offiine detection is not sensitive to the bushing faults, that is to say, the bushing faults barely changes frequency response curves or causes misjudgment of winding deformation. Meanwhile, for online detection, both capacitive and resistance-capacitive bushing faults change the amplitudes of online frequency response curves： the amplitude of frequency response curve is positively related to the equivalent capacitance of the bushing, and this rela- tion is more obvious in 10-40 kHz which leads to misjudgment of winding deformation detection using the correlation coefficients of transfer functions. Since the shape of online frequency response curve is not affected by resistive bushing faults, it is concluded that the capacitive factor of bushing is the main reason of the curves＇ change.

关 键 词：绕组变形 频率响应分析法 套管 等效电路模型 在线测试 离线测试 

分 类 号：TM407[电气工程—电器]