XLPE电缆绝缘介质损耗角正切测试方法的探讨

为了提高交联聚乙烯(XLPE)绝缘电力电缆介质损耗角正切(tgδ)测量的准确性,对电缆试样制作保护环等问题进行了深入地探讨,即在一定的测量电压下,采用不同的保护环以及保护环与绝缘屏蔽之间不同的距离,对tgδ测量值的影响进行了探讨,并对测量工作提出了应注意的若干问题。结论是采用自粘铜带绕包是最好的保护环材料,保护环与绝缘屏蔽层之间的距离最佳为2~5 mm,测量的精度最高,可忽略绝缘表面泄漏电流的影响。

On the Measurement of Tangent of Dielectric Loss Angle in XLPE Cables

In order to raise the accuracy of the measurement of tangent of dielectric loss angle(tgδ) in XLPE cables,efforts were made to explore the effect of sample preparation and use of protective ring,i.e.the effect of different protective rings and different distance between the protective ring and the insulation shield on the accuracy of the tgδ measurement under a given measuring voltage.Matters needing attention for the measurement are also presented.The conclusions drawn are that the best protective ring consists of wrapping by bondable copper type and the optimized distance between the protective ring and the insulation shield which gives the highest measurement accuracy is between 2 and 5 mm.The effect of the leaking current on the insulation may be ignored.