模拟实际运行工况的变压器油流带电特性

摘要

Electrostatic charging is widely found in forced oil-circulation cooling transformers.And it is an increasing risk in discharge to threaten transformers' operating life with the aging of transformer oil.In this study, artificial accelerated thermal aging oil samples (with 5 kinds of aging hours)and operating aged oil samples (with 5 kinds of running hours)are chosen for comparison.Firstly, the effects of oil flow velocities on the electrostatic charging tendency (ECT)is investigated for the artificial aging samples.Secondly, a relationship between these two types of aging methods is established based on the ECT, dielectric loss and volume resistivity of oil samples at different aging degrees.It is found that the artificial accelerated thermal aging method can stimulate the aging process of transformers under operating condition, which provides the necessary theory and experimental basis for the practical operation of transformer aging evaluation technology.%变压器油纸绝缘系统内普遍存在着油流带电现象.随着变压器油老化程度加剧, 不断上升的油流带电度容易引发变压器油放电甚至击穿现象, 极大地威胁着变压器绝缘系统运行寿命.该研究以人工加速热老化油样 (5种老化时间)与实际运行变压器老化油样 (5种运行时间)为对象, 首先研究人工加速老化油流带电度随油流速的变化规律, 然后对比研究不同老化程度下2种变压器油样的油流带电度、介质损耗、体电阻率等理化参数, 建立2种老化方法之间关系.研究发现:利用人工加速热老化方法可以模拟实现变压器运行工况, 为实际运行变压器老化评估技术提供了必要的理论与实验基础.