基于电流极化谱特征量的油纸绝缘变压器微水含量评估

Evaluation of moisture content in the oil-paper insulation transformer based on the characteristic of current polarization spectrum

微水是变压器的头号敌人,因此准确评估诊断变压器微水含量具有重要意义。针对油纸绝缘变压器,提出一种采用电流极化谱特征量进行微水含量评估的方法。首先,利用去极化电流微分解谱法分析变压器去极化过程,并提取电流极化谱特征量。然后,进一步分析特征量与油纸绝缘微水含量的关系,以此作为油纸绝缘系统微水含量评估判据,并得出结论:去极化电荷量越大,变压器微水含量越高;反之,去极化电荷量越小,变压器微水含量越低。最后,通过变压器实例验证了该判据的准确性和可行性,为变压器微水含量评估提供了一种有效的评估方法。

Moisture is one of the influencing facts in deteriorating the insulating properties of transformer.Moisture assessment can effectively judge the performance of transformer and avoid catastrophe failures.In this paper,an evaluation method of moisture content is proposed for an oil-immersed transformer based on the current polarization spectrum.Firstly,the depolarization process of transformer is analyzed by the differential spectroscopy decomposition of depolarization current to extract the characteristic parameters.Then,a relationship is established between those characteristic parameters and the moisture content in oil-paper to evaluate the moisture content in transformer insulation system.The results show that the greater depolarization charge corresponds to the higher moisture content in transformer.Finally,a real model transformer is used to test the accuracy and feasibility of the criterion.It is shown that the current polarization spectrum provides an effective evaluation method for assessing the moisture content in transformer.