老化方式对交流交联聚乙烯电缆空间电荷分布的影响

Influence of Aging Mode on Space Charge Distribution of AC XLPE Cables

为了研究高压交流交联聚乙烯(XLPE)电缆老化状态与绝缘空间电荷特征的关系,通过测量高压交流交联聚乙烯(XLPE)电缆不同位置绝缘的空间电荷特性,分析了老化方式对XLPE电缆空间电荷分布规律的影响。采用电声脉冲(PEA)法测量XLPE内空间电荷分布规律,发现未老化电缆铝电极附近积累同极性电荷,而老化后电缆的铝电极附近积累异极性电荷。沿电缆径向由内向外,未老化电缆及实际运行22a电缆电荷量增高,加速老化1a电缆电荷量降低。分析认为,加速老化电缆的老化可能起始于电缆绝缘内侧,实际运行电缆老化可能起始于电缆绝缘外侧。结果表明不同老化状态下交流XLPE电缆绝缘空间电荷行为明显不同,空间电荷测量可以作为评价交流XLPE电缆老化状态的有效手段。

In order to investigate the relationship between the aging state of HV AC XLPE cable and the characteristic of space charge of XLPE,we studied the space charge distribution of HVAC XLPE cables under different aging modes.Moreover,we adopted pulsed electro-acoustic（PEA）method to measure the evolution of space charge inside the insulating materials that were got from different position of AC cables.It is found that the total charge amount of insulating materials from un-aged cables and cables under actual operation increases along the radial direction from inner to outer,while the total charge amount of insulating materials from accelerated aging cables decreases.Space charge of accelerated aging cables starts from the inside of the insulating materials,while it starts from the outside of cables aged under normal operation.It is suggested that the space charge characteristics of AC XLPE cable insulation varies with its aging state obviously,thus the space charge measurement can be used as an effective method for aging state assessment of AC XLPE cable.