材料期刊网

随着电力电缆行业的持续发展,XLPE电缆绝缘检测技术受到越来越多的关注.对电缆绝缘老化状态的有效评估是当前电气设备管理一个十分重要和必不可少的过程.根据IEEE提出的有关电力电缆绝缘超低频(0.1 Hz)试验标准,提出一种对XLPE电缆绝缘分层取样,测量切片试样在0.1 Hz下的tanδ随外施电压的变化,以电压敏感度来判断绝缘老化程度的方法.通过测量不同运行年限的XLPE电缆绝缘,发现tanδ随外施电压的变化规律可以有效反映出不同运行时间绝缘老化状态的区别,绝缘内、中、外层的tanδ存在差异性.将老化电缆绝缘内层和中层的tanδ以外层tanδ测量值作为基准进行归一化,利用相对值的变化规律作为绝缘老化状态判断依据.实验结果表明,该方法对原始数据缺失的电缆绝缘老化状态评估是一种有效手段.

The detection technology of XLPE cable insulation has recieved more and more attention with the continuous development of power cable industry. It is an important and indispensable process of elec-trical equipment management at present for the effective assessment of cable insulation ageing condition. According to the IEEE test criteria about cable insulation diagnosis method at very low frequency (0.1 Hz), a new method was put forwarded to assess the ageing condition of XLPE insulation. The sam-ples were sliced from XLPE cable insulation layer, and the tanδ of the slice samples at 0.1 Hz were tested under different voltages, and then the voltage sensitivity was used to judge the ageing dgree of insulation. It is found that the change rule of tanδ with voltage can effectively reflect the difference of insulation ageing condition for the power cables after operating different years, and the tanδ of inner, middle, and outer insulation layers is different. The tanδ of inner and middel layers is normalized by set-ting the tanδ of outer layer as reference, and the relative value is used as a judgement basis of insula-tion ageing state. This method is an effective way for ageing condition assessment of XLPE cable insula-tions which are lack of original data.