摘要
为研究高压交流套管的油纸绝缘热老化特性,用套管用绝缘油、绝缘纸及铝箔纸自制成样品并分别在90℃、100℃、130℃三种温度下进行加速热老化。对热老化过程中反映油纸绝缘材料样品老化状态的理化特征参数进行测试与分析。同时,对套管缩比模型在100℃进行电热联合老化实验,测试分析其在老化过程中相应的介电响应曲线,测试套管在绝缘失效并解体后的绝缘电气/理化参数。结果表明:对于套管的多层油纸屏障结构,最外层油纸绝缘是套管绝缘特性的薄弱点。油纸材料样品与套管缩比模型在老化过程中最外层绝缘纸的聚合度下降速率均最快,内层较慢,分析认为水分和油酸在各层间的分布规律是导致该现象的主要原因;相比传统的工频电容值,低频段对应的电容值对绝缘状态变化反映更为灵敏。以油纸绝缘材料样品最外层绝缘纸的聚合度随温度与时间变化数据为依据,建立了套管油纸绝缘热寿命模型,并初步验证了该模型的有效性。
To investigate the thermal aging characteristics of the oil-paper insulation in high voltage( HV)bushings,the paper and aluminum foil wrapped copper winding models combined with the insulating oil are used to perform the thermal aging experiments under 90 ℃,100 ℃,and 130 ℃,respectively. Physical / chemical parameters,which can reflect the aging condition of the oil-paper insulation, are measured and analyzed. In addition,the electro-thermal aging experiment of the scaling bushing is carried out under 100 ℃ as well in order to obtain the dielectric response,and the electrical characteristics and physical / chemical parameters after the bushing has a breakdown. Experimental results show that the outermost layer of the bushing manifests the lowest dielectric strength among multilayer oil papers. The descending speeds of the degree of polymerization( DP) for the outermost layer paper both in the paper wrapped copper winding model and the scale bushing are the fastest,whereas the inner layer papers are slower. The distribution of moisture and oleic acid is regarded as the reason for this phenomenon. It is also found that low frequency capacitance is more sensitive to the variation of insulation status of bushing compared with traditional power frequency capacitance. The oil-paper insulation thermal aging lifetime model for the bushing is then established based on the relationship of the outermost paper layer's DP changing with time. The effectiveness of the model is preliminarily verified.
出处
《电工技术学报》
EI
CSCD
北大核心
2016年第5期144-151,共8页
Transactions of China Electrotechnical Society
基金
国家创新研究群体基金资助项目(51021005)
关键词
套管
油纸绝缘
老化特性
寿命模型
Bushing
oil-paper insulation
aging property
lifetime model
