泄漏电流相角变化特征与绝缘子运行状态的相关分析  

Phase Angle Characteristics of Leakage Current and Analysis on Outdoor Insulator Performance

作　　者：刘勇[1] 杜伯学[1] 刘弘景 王荣亮[3] 

机构地区：[1]天津大学电气与自动化工程学院,天津300072 [2]国网北京电力科学研究院,北京100075 [3]天津市高压供电公司,天津300250

出　　处：《高电压技术》2012年第4期831-837,共7页High Voltage Engineering

基　　金：国家自然科学基金(50777048);天津大学自主创新基金(2704)~~

摘　　要：绝缘子运行状态直接关系着输变电线路的安全运行。由于泄漏电流贯穿绝缘子运行始终,其能直接反映绝缘子表面状态及放电特征,故可利用泄漏电流相角变化特征对典型污湿运行环境下绝缘子运行状态进行评估研究。以硅橡胶复合绝缘子为试样,在人工大气模拟实验装置内模拟典型污湿环境,盐雾电导率为1.0～5.0mS/cm,相对湿度为70%～100%,环境温度为25～40°C。当施加30kV工频交流电压后,采用数据采集卡装置采集流过绝缘子表面的泄漏电流,采样率为22.05kHz。通过快速Fourier变换(FFT)分析了绝缘子表面运行状态的泄漏电流相角变化,建立了泄漏电流与运行电压的相角差及其变化规律与相对湿度、环境温度和污秽等级的对应关系。结果表明:随着相对湿度的增大,相角差呈现减小的趋势,并在相对湿度达到100%时呈现骤减的特征;随着环境温度的升高,相角差呈现缓慢减小的特征;随着污秽等级的提高,相角差呈现减小的趋势。泄漏电流的相角变化特征可以用于绝缘子运行状态监测及污湿等级划分,从而提高户外绝缘子运行的可靠性与准确性。With wide application of outdoor insulators in the transmission lines,the operation performance becomes one of the prominent factors affecting the stability and reliability of power system.The phase angle characteristics of leakage current can be used to evaluate the performance under typical contamination-humidity environments.For monitoring the insulator performance in such conditions,we established an artificial fog chamber and employed an ultrasonic vibration salt-fog generator filled with saline solutions to simulate different contamination-humidity environments.Silicone rubber outdoor insulators were used as specimens.And the test conditions were controlled to be the relative humidity from 70% to 100%,the contamination level from 1.0 mS/cm to 5.0 mS/cm at the temperature from 25°C to 40°C.AC voltage of 30 kV at 50 Hz was employed as the test voltage and the leakage current was measured by using a high-speed A/D converter with the sampling frequency of 22.05 kHz.The phase angle characteristics of the leakage current and the applied voltage were obtained by adopting the fast Fourier transform（FFT） spectral analysis method.By analyzing the variation of phase angle in relation to the surface performance,we established the relationship among the phase angle values,the relative humidity,the environmental temperature and the contamination level.It is found that the decrease in the phase angle values can increase the relative humidity,the environmental temperature and the contamination level,in which the phase angle shows the notable decrease at the relative humidity of 100%.Accordingly,it is considered that the phase angle characterization of leakage current can be utilized to identify and monitor the insulator performance,which is helpful to enhancing the running reliability and veracity of outdoor insulator.

关 键 词：绝缘子 泄漏电流 相角特征 相对湿度 环境温度 污秽等级 状态监测 

分 类 号：TM216[一般工业技术—材料科学与工程]