基于频域介电谱分析的高压套管绝缘状态评估

Insulation Evaluation of High Voltage Bushing Based on Frequency Domain Spectroscopy Analysis

为了解决高压套管现场检测手段有限、诊断准确性差的问题，改善目前高压套管事故多发的现状，采用新型无损检测方法对高压套管绝缘老化和受潮状态进行评估，对提高高压套管的运行可靠性具有重要意义。笔者采用基于介电响应理论的频域介电谱法（FDS），对3支结构相同的油纸绝缘高压套管在不同温度、含水量以及热老化时间下FDS测试的介损频率曲线进行了对比和分析，通过0．01～1000Hz频段的FDS测试的介损频率曲线来评估套管纸绝缘的含水量。研究结果表明，FDS测量的套管介损频率曲线受温度、含水量和老化时间等因素的影响，介损频率曲线的低频部分对套管纸绝缘含水量更敏感。而通过FDS测试评估套管纸绝缘含水量也可定量分析套管内部纸绝缘的老化和受潮状态。相比传统工频介质损耗测量．频域介电谱测量能够更灵敏和较全面地反映套管内部绝缘老化和受潮状态，具有较好的工程应用价值。

accuracy, To develop new on-site insulation detection method of high voltage bushings and improve the diagnostic three oil-immersed paper insulated high voltage bushings with same structure were tested with the frequency domain spectroscopy （FDS） method in dielectric response theory. FDS test was conducted under different temperature, paper moisture content and thermal aging time to obtain the dielectric loss frequency curves. The dielectric loss frequency curves within 0.01~1 000 Hz were used to evaluate the water content of the bushings. The results show that the dielectric loss frequency curves in lower frequency range are more sensitive to moisture content of the paper insulation due to the effects of temperature, and aging time. The analysis of paper moisture content via FDS measurement can also help to evaluate aging and moisture conditions of the bushing. Compared with conventional power frequency dielectric loss measurement, the FDS measurement is more sensitive to insulation aging and moisture condition in a high voltage bushing.