套管故障对变压器频响曲线影响的仿真研究

发布时间：2019-02-26 09:44

【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。
[Abstract]:When the transformer winding deformation detection is carried out on-line or off-line by the frequency response method, the influence of the casing state on the frequency response curve is often ignored, not only is the judgment of the winding fault, but also the accident potential is easily caused. In this paper, a new equivalent circuit model of the transformer is established. The parameters of the model are obtained by using the method of software simulation and numerical calculation, and the resistance of the casing is studied by means of on-line and off-line method based on the frequency response analysis method (FRA). The change of the frequency response curve of the transformer at the time of capacitive, resistance/ capacitive fault. The results show that when the frequency is 1 kHz to 1 MHz, the off-line test of the transformer is insensitive to the resistance of the casing, the capacitance, the resistance/ the capacitive fault, which does not cause the change of the frequency response curve and the misjudgment of the winding, and when the on-line test, The capacitive and/ or capacitive faults of the sleeve can cause the change of the frequency response curve, and the size of the casing capacitance in the whole frequency band is positively correlated with the amplitude value of the frequency response curve, and the phenomenon is most obvious when the frequency is 10-40kHz, and the transformer winding deformation is misjudged according to the correlation coefficient; However, the resistance of the casing is not affected by the trend of the on-line test frequency response curve, and the main cause of the change of the frequency response curve of the on-line test transformer is determined as the casing capacitance factor.
【作者单位】：西安交通大学电力设备电气绝缘国家重点实验室;甘肃电力科学研究院;
【基金】：国家电网公司科技项目(522722130397)~~
【分类号】：TM407

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