基于局部放电统计参量的脉冲电压下绝缘老化分析

主要针对匝间和对地绝缘电磁线在脉冲电压下老化后的局部放电特征进行了研究.通过不同老化时间的局部放电相位相关分析,在高频脉冲电压下老化后放电次数相位分布出现明显的"放电丛"现象,并通过工频老化后的局部放电结果对此加以证实.通过两种不同电磁线老化特征对比,匝间绝缘和对地绝缘呈现不同的放电特征,匝间主要以内部气隙放电为主,而对地绝缘电磁线则以槽放电为主.此外,测量和分析了局部放电统计参量(如偏斜度、峭度、不对称度等)随老化时间的变化,结果表明平均放电量的偏斜度和老化时间有着一定联系.为更深入地研究脉冲电压下绝缘老化机理打下了坚实的基础.

Analysis of Aging Properties for Insulation Based on Statistical Parameters of Partial Discharge Under Pulse Voltage

Properties of partial discharge (PD) of magnetic wires for interturn insulation and insulation to ground are investigated at different aging time under pulse voltage. Through phase resolved PD patter with aging time, clusters of discharge number occurred with increase of aging time. Comparing the results of phase resolved PD patter at 50Hz AC and pulse voltage, no similar phenomena are observed at 50 Hz AC voltage. Behaviors of PD for two different types of winding wires are compared, and internal void discharge played the leading role for winding wires for interturn insulation, and PD of winding wires for insulation to ground is mainly caused by slot discharge. Furthermore, statistical parameters of partial discharge (e.g., skewness, kurtosis, degree of asymmetry) in wingding wires at different aging time are also obtained in order to show relationships between partial discharge statistical parameters and aging time. After detailed analysis, we can conclude that there is a strong relation between skewness of mean discharge quantity and aging time. These conclusions could be used to further investigate properties of aging under pulse voltage.