考虑绝缘老化或受潮的变压器绕组变形判据优化

Optimization of Transformer Winding Deformation Criterion Considering Insulation Aging or Dampness

频率响应分析法是检测变压器绕组变形的重要手段。研究表明,绝缘老化或受潮会对变压器绕组频率响应测试结果产生影响,进而导致绕组变形的诊断中存在误判的可能,然而这一问题目前并没有较好的解决方法。以绝缘老化或受潮情况下的绕组变形诊断判据的优化方法为中心,首先通过油纸绝缘的受潮和老化试验与频率响应仿真相结合的方法,获得了不同受潮和老化程度下的绕组频率响应曲线;其次计算了绝缘老化或受潮情况下的相关系数R,根据相应的判据进行了绕组变形的初步判断;最后提出了2种判据优化方法。研究结果表明,在利用相关系数R判据对变压器绕组变形进行诊断时,绝缘老化或受潮均可能导致误判。通过调整相关系数R判据的频率范围,可以避免特定接线方式下的绕组变形误判;通过引入基于电容变化率的辅助判据,可降低绝缘老化或受潮引起绕组变形误判的可能性。

Frequency response analysis is an important measure detecting transformer winding deformation.However,the frequency response results will be affected by transformer insulation state,such as insulation aging or dampness,thereby giving a wrong diagnosis result of transformer winding deformation.But there is no better solution to this problem at present.This paper focuses on the optimization method of winding deformation diagnosis criterion due to insulation aging or dampness.Firstly,the frequency response with different dampness or aging degrees was obtained with the damp or aging test of oil-immersed paper and frequency response simulation.Secondly,the correlation coefficient of frequency response curves with insulation aging or dampness was calculated.Finally,two criterion optimization methods were proposed.Research results indicated that the insulation aging or dampness will cause misjudgment of winding deformation diagnosis with the criterion of correlation coefficient R.By adjusting the frequency range of the correlation coefficient criterion,the misjudgment in specific wiring modes will be avoided.By introducing the auxiliary criterion based on capacitance change rate,the misjudgment possibility in both wiring modes will decrease.