摘要
局部放电检测是保障电力电缆正常运行提供了最为可行的手段之一,但其对电缆附件硅橡胶绝缘中电树枝老化状况的诊断理论依据尚十分不足。为此,通过试验同步观测了高压电缆附件用硅橡胶材料电树枝老化过程中的图像和局部放电特征。研究表明:局部放电频次–相位–放电量呈现宽相位范围内的随机分布特性;放电与电树枝老化图像说明放电次数与电树枝分形维数随电树枝发展同时增长,当局部放电频次高时,硅橡胶中电树枝容易呈现树枝通道较为密集的丛状和松枝状电树枝。该研究首次将电树枝唯象特征与脉冲序列特性进行比较分析,发现大放电量脉冲对应电树枝通道的快速伸长;有明显主干通道时,正半周中较大的放电脉冲数对应主干道条数。唯象特征、脉冲序列特性、局部放电信号的综合分析为利用局部放电检测硅橡胶绝缘中的电树枝老化状态提供了理论基础。
At present, partial discharge（PD） test is one of the most available methods to detect the insulation status, but its theoretical foundation for evaluating the electrical treeing states in silicone rubber, which is used as the cable accessories＇ insulation material, is far from complete. Thus, we synchronously captured the optical images and partial discharge prop- erties of the electrical trees in silicone rubber in treeing experiment. The n-q-φ （the frequency-phase-capacity of PDs） patterns reveal that the discharges are randomly dispersed in a wide phase range. The PD properties and the characteristics of the micrographs indicate that the PD counting per cycle increases with the electrical tree fractal dimensions during the tree propagation. When the maximum PD quantities increase, the electrical trees in the silicone rubber appear to have more bush-like and pine-like patterns. For the first time, the phenomenological properties and the PD sequence patterns are put together to discuss their relationship. It is found that large discharge pulse corresponds to rapid elongation of electrical branch channel, and the number of larger discharge pulses in positive half-cycle corresponds to the number of main channels when there is an obvious arterial channel. The comprehensive analysis of phenomenological properties, impulse sequence properties and partial PD signals offers a theoretical basis for using PD tests to evaluate the electrical treeing aging status in cable accessories.
出处
《高电压技术》
EI
CAS
CSCD
北大核心
2015年第1期132-139,共8页
High Voltage Engineering
基金
国家重点基础研究发展计划(973计划)(2014CB239501)
国家自然科学基金(51377089)
国家电网公司科技项目(EPRIGYJSKF[2013]2441)~~
关键词
高压电缆附件
硅橡胶
电树枝
局部放电
树枝形态
脉冲序列
high voltage cable accessory
silicone rubber
electrical tree
partial discharge
tree morphology
impluse sequence
