检测变压器绕组变形的扫频阻抗法原理及应用

Principle and Application of Sweep Frequency Impedance Method for Detecting Transformer Winding Deformation

为了有效减少变压器绕组变形诊断的误判率,提出了一种新型变压器绕组变形检测方法——扫频阻抗法,以该法为理论基础建立了一套变压器绕组变形测试系统,并对一台三相变压器进行了测试。结果表明:扫频阻抗曲线50 Hz处的阻抗值与短路阻抗法的测试值呈现较高的一致性;在频率为500 Hz～1 MHz时,扫频阻抗法具有频率响应分析法的测试特点,能够有效描述绕组等效电路模型极值点的变化;在整个频段中,扫频阻抗法都表现出很高的测试灵敏度和重复性,因此该方法是一种可行且有效的变压器绕组变形检测方法。

To decrease the misjudge rate of diagnosing the transformer winding deformation, a novel method to detect transformer winding deformation was proposed, which is defined as sweep frequency impedance（SFI） method. A measurement system was set up to test a three-phase transformer based on SFI method. The results show that the impedance value when the frequency is 50Hz in SFI curve is approximately equal to the test value of short circuit impedance（SCI） method. When the frequency is 500 Hz～1 MHz,the SFI method has the characteristics of frequency response analysis method, which can describe the changes of extreme point of transformer equivalent circuit model and show super sensitivity and repeatability. Therefore, SFI method is a feasible and effective method to detect the winding deformation of transformer.