大中型发电机转子过励限制与过负荷保护控制策略及配合研究

近年来,伴随我国用电负荷不断增长,大中型电机在电网中所占比例越来越大。目前对于大中型电机转子过励限制和过负荷保护的研究一般局限于各自过流动作值的整定,而限制与保护定值的配合往往被忽略。同时对于电机运行过程中,转子绕组载流温升特性并未深入研究,给大中型电机的安全运行带来隐患。微机励磁系统一般配置顶值电流限制器,其控制策略及其与过励限制和过负荷保护的配合目前并无文献涉及。本文探讨了转子温升特性,在此基础上,提出励磁改进型转子过励限制、励磁顶值电流限制控制策略,并进行了仿真,对指导发电厂转子励磁与保护参数整定工作具有重要意义。

Study of the Control Strategy of Rotor Over-excitation Limit and Over-current Protection Applied to Large and Medium Generator

Recently, with the increasing growth of electricity load, the proportion of large and medium generator in power system is growing in our country. The study of rotor over-excitation limit and over-current protection applied to large and medium generator is restricted to setting over-current-curve value. Yet, whether the value is reasonable or not, the rotor thermal properties in the adjusting process is seldom mentioned, bringing certain hidden risks to the large and medium generator. The excitation system is usually equipped with maximum current limit, while the control strategy and its coordination with over-excitation limit and over-current protection have not been researched. In this paper, the relationship between rotor power-loss and rotor thermal properties is discussed, and on this basis, the approved control strategy and effective cooperation of over-excitation limit, maximum current limit and over-current protection is proposed, which can be used to guiding parameter settings during actual production, improving reliability and safety of electrical systems.