大电机主绝缘长期绝缘强度和剩余寿命评估的研究

Stator insulation of large generators is subjected to electrical, thermal, mechanical,thermal-cycling and environmental stresses simultaneously in service. The multiple stresses cause.insulation gradual aging, which leads to insulation failure finally.Assessment of insulation.condition and remaining life of stator bars after a period of service is of significance for the reliable operation of generator.A key project, “Study on the long-term dielectric strength of large generator ground wall insulation and evaluation of remaining lifetime”, was funded by National Natural Science.Foundation of P. R. China. The main idea of this project is to establish a mulltistresses accelerated aging system, to investigate the aging law of stator insulation, to propose the aging characteristic parameters and assess the remaining life of stator insulation. The main contents of the project concentrate on establishing a mathematical model in accordance with practice, seeking the agingcharacteristic parameters which can describe the aging condition of stator insulation properly, and.presenting a software for assessment of remaining life of large generator ground wall insulation,which should be verified on practical stator insulation.The research group of this project set up a multistress accelerated aging system, extracted a.group of aging characteristicparameters, proposed the aging law of stator insulation, developed several diagnostic systems of insulation condition, established a mathematical model to assess the.residual dielectric strength, proposed the aging mechanism of stator insulation, and presented a.software to predict the remaining life of stator insulation. These research results make a great contribution to intelligent diagnosis of insulation condition and precise prediction of remaining life of stator insulation in large generator.

研究大型发电机主绝缘性能变化规律及老化机理，建立评估剩余寿命的理论基础，找到提高发电机寿命的绝缘材料及结构；提出改进氧化锌材料性能的途径。可为高电压和绝缘技术学科的发展开辟新的领域，并且对于实现国民经济发展战略目标要求，发展我国电力事业，提高供电可靠性，提高大容量发电设备和高电压等级氧化锌避雷器的制造技术有重大意义。