【作者】 李毅；

【导师】 杜伯学；

【作者基本信息】 天津大学 ， 电力系统及其自动化， 2006， 硕士

【摘要】 近年来,有机绝缘材料凭借其制造成型简单、成本低廉及在良好的电绝缘性能等多方面的优势,正越来越广泛的使用在高电压电气设备上。但许多外在和内在的因素,例如,湿度温度的变化,表面残留的污秽,机械应力等等因素都会加快有机绝缘材料的老化。这些因素能够降低粗糙表面的疏水性,并将导致表面的漏电痕迹劣化,从而影响高电压电气设备的安全性和可靠性。为了更好的研究有机绝缘材料表面漏电痕迹的特性,更简单方便的评价材料的绝缘性能,本论文在大量实验的基础上,采用混沌和分形的方法,对表面放电电流波形中包含的放电特性进行了深入的研究。本文以IEC60112为试验方法,比较了在不同的放电电压下,酚醛胶合板(PL)、环氧树脂(EX)、聚对苯二甲酸乙二酯(PET)这三种材料的表面放电特性。在处理漏电痕实验数据的过程中,包括重构吸引子图和计算关联维数,不但可以多次证明这种几种材料的漏电流数据是一个混沌系统,而且计算的结果——关联维数还呈现出规律性。在较高的放电电压下,漏电流数据的关联维数也较大,而在较低的电压下,漏电流波形的关联维数也较小。多次的重复实验验证这个规律,因此可以把关联维数看作一个表征材料表面放电这个混沌系统的重要指标,来评估整个放电系统所处的状态。最后本文对PL、PET、EX等三种材料进行横向比较,研究了其材料绝缘特性的一些差异。更多还原

【Abstract】 The growing interest in polymer insulation materials for high voltage applications are mainly due to the simplicity in manufacture, good in-service performance and the low cost of these materials. However, studies show that whenever polymer insulation materials are exposed to an environment that is less than ideal, tracking becomes an imminent possibility. So tracking on the surface of polymer insulation material is consider as a major cause attached importance to the safety and reliability of running electrical equipment.In order to study the characteristic of tracking on the surface and evaluate the insulation ablity of polymer materials, a lot of experiments have been taken to measure the discharge currents. According to the characteristics of statistical self-similarity and complexity of the discharge current, an approach was presented to find the fractal dimension based on the embedding space theory, state space reconstruction and G-P algorithm.This paper makes an investigation of characteristic of suface discharge based on IEC60112. In this reaserch, 3 polymer insulation materials were used, they are PET, EX and PL. The results show that the fractal dimension can be used as an available feature for evaluating the insulation degradation of polymer insulating materials. The higher voltage applied in experiment, the more the fractal dimension is. At last, a comparison was made to point out the different characteristic of the 3 materials.更多还原