超高压变压器油中酸类物质的生成规律和变压器热老化状况分析  

Correlation Between the Generation of Acidic Products and the Thermal Aging of Oil-paper Insulation of the UHV Transformer

作　　者：李海燕[1] 何梦[1] 黄林[2] 姜胜宝[2] 林浩[2] 倪学锋[2] 

机构地区：[1]中南民族大学化学与材料科学学院,武汉430074 [2]中国电力科学研究院,武汉430074

出　　处：《高电压技术》2015年第6期1959-1964,共6页High Voltage Engineering

基　　金：湖北省自然科学基金(2013CFB456)~~

摘　　要：为了防止变压器突发性恶性事故发生,探寻更为准确地评估超高压变压器油纸绝缘老化状态和预测变压器剩余寿命的方法意义重大。为此,在130℃下进行了变压器油纸绝缘加速热老化实验,同时跟踪测定变压器油中的酸值、糠醛含量和介质损耗因数,分析模拟老化条件下生成酸类物质的规律,并与变压器老化特征量糠醛和油介质损耗因数的变化规律进行了对比分析。实验结果表明：在变压器油纸绝缘热老化过程中,老化生成酸性物质的反应分为反应诱导阶段和反应发展阶段。在老化反应进入诱导阶段后期,油中糠醛的含量下降,此后,油中的糠醛含量便不能正确反映变压器纸绝缘的老化状况。在老化反应的发展阶段,其反应速率常数是诱导阶段的约5~11倍。老化过程中变压器油中酸值的变化和介质损耗因数的变化具有良好的相关性,生成酸类物质反应速率的快速增加,与变压器油的绝缘性快速下降相一致。结果初步表明跟踪测定变压器老化过程油中酸值的变化,可更为准确地评估变压器油纸绝缘的老化。It is of significance to develop methods for assessing the aging status of oil-paper insulation in ultra-high vol- tage transformers and determining transformer lifetime accurately to prevent severe faults of transformers. We conducted accelerated thermal aging tests using transformer＇s oil-paper insulation at 130℃. In the tests, the acid value, furfural concentration, and dielectric loss factor of the oil-paper insulation were measured. Furthermore, we analyzed the reaction mechanisms of the acidic products during the thermal aging process, which were then compared with the variation of fur- rural concentration and dielectric as the main aging characteristic parameters. According to the experiments, during the thermal aging process, the aging reaction that generates acidic products could be divided into two phases, namely, the in- duction phase and the developed phase. The furfural content of transformer oil begins to decline in the late stage of the induction phase, and since then it is not able to reflect the aging situation of insulation accurately. In the developed phase, the reaction rate is notably larger than that in the introduction phase, i.e. it increases by about 4~10 times. The variations of oil dielectric loss factor and acid value are in accordance with each other, and the sharp increase of oil acid value cor- responds to the significant decline of oil-paper insulation performance. A preliminary conclusion is drawn that tracking the variation of acid value of transformer oil-paper insulation could be quite helpful to assessing the insulation aging accurately.

关 键 词：变压器 油纸绝缘 老化 酸类物质 糠醛 介质损耗因素 

分 类 号：TM855[电气工程—高电压与绝缘技术]