热老化对变压器油纸绝缘介电响应特征参量影响的研究

Influence of Aging and Temperature on the Characteristic Parameters Extraction Method of Transformer Oil-paper Insulation

基于介电响应理论的回复电压法、极化去极化电流法和频域谱法,作为无损的诊断技术正逐渐被应用于变压器油纸绝缘的状态评估。但是研究结果表明其测量结果会受测量过程中诸多因素的影响。在一个复杂的油纸绝缘系统中,水分在油纸之间的分布,迁移和平衡过程取决实际运行温度和老化程度。只有充分理解绝缘系统在温度和老化影响下的物理变化过程,才能更加准确的分析测量结果。本文引入了一种描述变压器油纸绝缘系统介电特性的电路模型,研究了该模型中各参数值的确定方法,最后设计了130℃下加速热老化试验和变温试验,分别在不同老化程度和不同温度下对试品进行了介电响应测量,根据测量结果分别研究了热老化和温度对介电谱法测量的影响;并基于介电响应测量曲线提取了介电响应特征参量,深入研究了热老化和温度对介电响应特征参量的影响规律。

Return voltage measurement（RVM）, polarization and depolarization current measurement（PDC）, and frequency domain spectroscopy（FDS）, which are based on the dielectric response, are currently widely used for condition assessment of transformer insulation as non-destructive testing methods.However, it has been reported that results of these tests are highly influenced by Many factors during measurements. The distribution, migration and equilibrium of moisture between oil and paper in a complicated insulation system is highly temperature and aging dependent. It requires adequate experience and proper understanding to interpret the dielectric response results in the presence of temperature or aging variations and thermal instability. Proper analysis of the dielectric test result is only possible with an understanding of the physical behavior of the insulation system in response to temperature.Finally an accelerated aging experiment at 130℃ and a temperature variation experiment are done.Dielectric response measurement is measured under different aging degrees and different temperatures.Based on the testing results,research the variation rule of dielectric response measurements under different oil-paper insulation aging status and different temperatures.On the other hand,the author extracted the time and frequency domain characteristic parameters from the dielectric response measurements curve,and a deep reaching is done about the aging and temperature effects on the Dielectric Response characteristic parameters of Transformer OilPaper Insulation System.