交流电压频率对GIS绝缘子内部气隙局部放电特性的影响  

Effect of AC voltage frequency on partial discharge characteristicsof void in GIS insulators

作　　者：赵琳 顾刘欢 金涌涛 邵先军 郭广怀 唐志国[2] ZHAO Lin;GU Liuhuan;JIN Yongtao;SHAO Xianjun;GUO Guanghuai;TANG Zhiguo(State Grid Zhejiang Electric Power Research Institute,Hangzhou 310014,China;Beijing Key Laboratory of High Voltage&EMC,North China Electric Power University,Beijing 102206,China)

机构地区：[1]国网浙江省电力有限公司电力科学研究院,浙江杭州310014 [2]华北电力大学高电压与电磁兼容北京市重点实验室,北京102206

出　　处：《电机与控制学报》2025年第2期126-135,共10页Electric Machines and Control

基　　金：国网浙江省电力有限公司科技项目(5211DS23000B)。

摘　　要：柔性低频交流输电在中远距离海上风电送出中具有优势,但工频下广泛应用的局部放电带电检测技术面临着无法直接在低频输变电设备上应用的问题。为此,以GIS绝缘子内部气隙缺陷为研究对象,首先理论分析了频率对绝缘材料介电常数及电导特性的影响,其次在经典三电容模型基础上仿真研究了不同频率下绝缘内部气隙局部放电特征的差异,最后采用特高频法开展了20~100 Hz范围内的气隙局部放电试验研究。结果表明:随着频率的降低,环氧树脂材料的介电常数略有增加,介质损耗角正切tanδ减小,环氧树脂的电导下降,由此引起气隙缺陷部位电场略有上升和电容时间常数的增大,导致相较于工频,低频20 Hz下起始局放电压有所升高,每周期平均脉冲重复率下降20%;同一电压等级下,低频下PRPD图谱形状、幅值分布范围无明显变化,工频下的PRPD图谱经频率归一化后可作为低频下气隙放电的诊断依据。研究结果可为低频输变电设备的局放检测和诊断提供参考。Flexible low-frequency AC power transmission has advantages in medium and long distance offshore wind power transmission,but the partial discharge on-line detection technology widely used in power frequency is faced with the problem that it cannot be directly applied to low-frequency power transmission and transformation equipment.Therefore,the void defects in GIS insulators were taken as the research object.Firstly,the effects of frequency on dielectric constant and conductivity of insulation materials were considered,and the difference of void partial discharge characteristics in insulation at different frequencies was simulated based on the classical three-capacitance model.Finally,an experimental study of void partial discharge in the range of 20-100 Hz was carried out by using UHF method.The results show that with the decrease of frequency,the dielectric constant of epoxy resin slightly increases,the tangent of dielectric loss angle“tanδ”decreases,and the conductivity of epoxy resin decreases,resulting in a slight increase in the electric field at the defect site of the void and an increase of the capacitance time constant.Compared with the power frequency,the PDIV at low frequency 20 Hz increases,and the average pulse repetition rate per cycle decreases by 20%.Under the same voltage level,the shape and amplitude distribution range of the PRPD spectrum at 20 Hz do not change significantly.After frequency normalization,the PRPD spectrum at power frequency can be used as a diagnostic basis for void discharge at 20 Hz.The research results provide reference for the detection and diagnosis of low-frequency power transmission and transformation equipment.

关 键 词：低频交流输电 气隙缺陷 三电容模型 材料电气特性 统计参数 局部放电图谱 

分 类 号：TM595[电气工程—电器]