基于频域介电谱法的变压器油纸绝缘套管受潮状况分析

Study on Moisture Assessment of Oil-Paper Insulated Bushings Based on Frequency Domain Spectrum

近年来频域介电谱法(frequency domain spectrum,FDS)作为一种无损检测方法,逐渐被尝试用来检测大型变压器、套管等油纸绝缘设备的绝缘状态。采用该方法对某500 kV变电站主变压器高中压中性点套管及低压故障套管进行了现场离线测量,然后将所测结果与实验室结果进行比对,分析其故障原因,实现了对现场实测数据的定性和定量分析,确认该批次套管存在出厂时套管芯子干燥不充分问题。研究表明,频域介电谱法不仅能够定性地反映套管内部受潮状况和受潮原因,而且还可以对其受潮程度进行定量分析,从而为该方法在实际生产中的进一步应用提供了理论和实践基础。

In recent years,the frequency domain spectrum（ FDS） as a non-destructive method has been gradually applied to the oilpaper insulation assessment of power equipment such as power transformers and bushings. In this paper,FDS method has been applied to the insulation condition assessment of neutral bushings and low-voltage bushings of an off-line transformer in a 500 kV substation,and then the result is compared with that obtained in laboratory to find the cause of fault through the qualitative and quantitative analysis of the field data. It is confirmed that the condenser bodies of the batch of investigated bushings are insufficient drying. It is considered that FDS method is not only adequate for qualitatively reflecting the wetting condition in oil-paper insulation of bushings,but also for quantitative assessment of moisture content of bushings,and provides the theoretical and practical basis for the future application of this method in practice.