摘要 本文旨在研究油纸绝缘介质老化机理与弛豫响应特征量之间的内在关系,将RVM(Return Voltage Measurement)技术应用于油纸变压器绝缘状态的无损诊断.通过RVM实验测量平台,测得恒温条件下不同微水含量,不同内部结构和不同老化状态的油纸绝缘样品对应的回复电压时域极化谱线,根据实验数据分析出不同绝缘状态下油纸绝缘时域极化谱特性参数的变化规律,并结合介质极化响应理论,阐明特征参数弛豫特性变化机理.实验结果表明:时域回复电压极化谱中回复电压最大值和主时间常数的位置改变,能有效反应油纸绝缘受潮和老化情况;初始斜率在充电时间10-2~101s,峰值时间在充电时间101~104s的量值大小,构成无损诊断的信息依据;初始斜率是老化程度的直接反馈参量,以区分水分对极化谱特性的影响;主时间常数可甄别绝缘结构不同的变压器绝缘状态,其与微水含量的指数函数关系,可用于延缓变压器受潮,提高运行可靠性.
Abstract：Return voltage measurement(RVM) is being investigated for condition assessment of transformer insulation, in order to study inherent laws between the mechanism of oil-paper insulation aging and the characteristics of relaxation response. A measurement platform is established for RVM experiments at a constant temperature in the paper, and time-domain polarization spectrums of return voltage are tested with different water content, geometric conditions and aging conditions. The variation of oil-paper insulation transformer’s return voltage is analyzed by the experimental data and dielectric polarization response theory. The results of experiments show that polarization spectrums of return voltage can be used to diagnostic the water content of oil-paper insulation transformer and aging conditions; not only the initial slope of the charging time between 0.01s and 10s but also the peak time of the charging time between 10s and 10 000s are important basis for non-destructive diagnosis; the initial slope can directly reflect the aging degree, which is used to distinguish the effects of moisture on the polarization spectrums; dominant time constant which is exponential relationship with moisture content can identify the condition of different transformer, it’s significant to delay the transformer moisture and improve its operational reliability.
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