直流高压干式套管的多参量诊断

Multi-parameter Diagnosis of HVDC Bushing

准确诊断干式套管主绝缘的老化状态,对于电力系统的可靠运行及状态检修具有非常重要的意义。为此,分别测量了干式套管主绝缘试样的介质损耗参量、泄漏电流、局部放电参量和剩余击穿电压,采用基于统计学的方法建立了多参量诊断的数学模型,对干式套管主绝缘进行了老化状态评估。结果表明:所测参量中,偏斜度Sk+、介电损耗tanδ、局放起始电压UPDIV、吸收比Pi为最优参量组;多参量诊断会提高绝缘状态评价的准确性,但也并不是参量越多越好,合理的选取诊断参量十分重要。

It is of great significance to diagnose the aging state of HV bushing insulation for residual lifetime assessment and condition-based maintenance of power transformers.Dielectric loss parameter,leakage resistance,partial discharge（PD） parameters,and residual breakdown voltage of bushing samples of different aging states were measured.On the basis of statistical theory,a method to quantitatively determine the reliability of multi-parameter diagnosis and to optimize the algorithm of multi-parameter diagnosis is put forward.Results show that,among all the parameters,multiple parameters are chosen to be partial discharge inception voltage（UPDIV）,skewness（Sk＋）,dielectric loss parameter（tanδ）,and absorption ratio（Pi）,and the result of multi-parameter prediction model is more accurate than that of single-parameter prediction model when choosing the appropriate parameters group.To choose an appropriate amount of parameters is important for assessing insulation condition.