【作者】 马力；

【导师】 杜伯学；

【作者基本信息】 天津大学 ， 电力系统及其自动化， 2004， 硕士

【摘要】 在有机绝缘材料的使用过程中,由于灰尘、雨滴及大气中的杂质附着在材料表面,将会导致其表面绝缘性能下降,引起反复放电。随着放电的进行,绝缘材料表面会出现炭化导电轨迹。炭化导电轨迹的产生,降低了有机绝缘材料表面的导电能力。在各种复杂环境下使用有机绝缘材料时,如果人们不能准确的评价其使用特性或及时诊断其老化程度,很容易发生短路、火灾等严重电力事故。目前,有机绝缘材料表面放电特征的研究已成为高电压绝缘的一个重要课题。初步的研究结果表明,有机绝缘材料表面放电过程十分复杂,具有很强的非线性特性。本文以有机绝缘材料表面为对象,在两种特殊环境下,对绝缘试样的表面进行了放电试验,并采用混沌与分形分析方法,来研究表面放电特征。首先,本文采用直流电压和交流脉冲电压对有机绝缘试样进行了表面放电试验,然后运用时间序列的混沌与分形分析方法对绝缘试验表面的放电电流数据进行了研究。结果表明,有机绝缘材料表面放电随着放电的进行,放电特征受表面树枝状炭化导电痕迹的影响,放电过程的随机性减弱,分形维数减小。然后,为了研究低气压对表面放电特征的影响,本文使用真空泵来抽空气的方法,在人工气压仓中模拟低气压条件,进行了表面放电试验。然后,对所得到的放电数据进行了混沌与分形分析。通过比较不同气压下放电电流的分形维数,吸引子相图等,可以发现低气压下,聚对苯二甲酸丁二醇脂材料表面放电的随机性减弱,放电时产生的炭化轨迹的复杂程度降低。最后,针对表面放电过程中存在的非线性特点,采用混沌判断方法对有机绝缘试样表面的混沌特性加以验证。在此基础上,运用混沌预测方法对表面放电电流时间序列数据进行了预测,为进一步研究表面放电的混沌特性提供了新的理论依据。更多还原

【Abstract】 In the course of using ploymer insulating material, the dust, raindrops and impuritiesin atmosphere will adhere to the surface. This phenomenon causes the insulatingability of surface of material to drop and discharge repeatedly. Going on withdischarging, the conductive marks of charcoal will present. The appearance of themarks can reduce the superficial conductive ability. While the materials are usedunder various kinds of complicated environments, such serious electric accidents asshorting out, fire, etc. are very apt to happen if people cannot accurately appraise theircharacteristic or diagnoses their aging degree in time. At present, the research oncharacteristic of surface discharge has become an important subject. Thepreliminary results of study show that the courses of discharges on the surface oforganic insulating material are very complicated and have very strong non-linearcharacteristics. In this paper, the surface discharge tests were carried on, and then thechaos and fractal methods were adapted to study the discharge characteristic.Firstly, the tests of surface discharge were carried on. Then, combining thephenomenon of testing, the chaos and fractal analytical methods were used to studythe variation tendency of superficial discharging characteristic. The results show that,the discharge characteristic was affected by conductive branch marks of charcoalformed on the surface. The randomness of discharge course subsides, and the fractaldimension reduces.Secondly, in order to study the characteristic of surface discharge influenced by lowpressure, a test was carried on in a glass container. A vacuum pump was used to pumpthe air to simulate a low-pressure condition. The results of fractal dimensions andphase graphs of discharge currents show that, under low-pressure conditions, therandomness of discharge course subsides, the complexity of the charcoal marksproduced in discharging progress reduced.At last, chaos judging and predicting method was adopted to investigate thenon-linear characteristic that exists in the course of surface discharge on polymerinsulating samples.更多还原