同步发电机失磁过程分析与保护方法研究  

Analysis on Loss-of-excitation Process and Research on Protection Method of Synchronous Generators

作　　者：林莉[1] 张向伍[1] 郭文宇[2] 何月[1] 

机构地区：[1]重庆大学输配电装备及系统安全与新技术国家重点实验室,重庆400030 [2]北京市电力公司密云供电公司,北京101500

出　　处：《高电压技术》2014年第11期3544-3553,共10页High Voltage Engineering

基　　金：国家重点基础研究发展计划(973计划)(2009CB724503);中央高校基本科研业务费(CDJZR12110024)~~

摘　　要：为寻求动作可靠的大容量同步发电机的失磁保护方法,对同步发电机失磁后的动态过程进行了数值仿真计算,提出了基于直测功角来判断发电机的一摆和多摆稳定性的失磁保护新方法,进而提出了该保护的设计原则、配置方案、整定条件和计算方法,同时,通过动模实验对新的保护判据进行了分析验证。由数值仿真计算和动模实验可得,转子励磁电流的衰减和异步功率分量的出现使失磁后的发电机的动态功角特性与静态功角特性有很大的差别,功角的上升也可使测量阻抗进入异步边界阻抗圆,且失磁后发电机的功率角与转差率变化趋势明显。结果说明电网发生扰动引起功角上升的因素均可导致阻抗保护误动,而新的保护较现行保护能更可靠、更快速地反应励磁故障,减少保护的误动率和拒动率。同时证明了对失磁发电机实施减载控制使之再同步的可行性。To further study the loss-of-excitation process of synchronous generator and to seek a reliable method of excitation fault protection, the simulative calculation is conducted, and the new excitation fault protection method is put forward based on directly measuring power angle to judge the first pendulum or more stability of synchronous generators, then, the design principles, configuration scheme, setting conditions, and calculation method of the protection by power angle are proposed. The proposed excitation fault protection is verified by means of dynamic simulation experiment. Results of simulative calculation and experiment indicate that it is different between the dynamic and the static power-angle characteristic of synchronous generator after loss-of-excitation because of the attenuation of excitation current and the appearance of asynchronous power, and the measuring impedance can enter the asynchronous boundary impedance circle by increasing of power angle, in addition, the variation of power-angle and slip is evident after loss-of-excitation. Thus, it is proved that the factors of the increase of power angle caused by system disturbances should lead to impedance protection malfunction. And the new excitation fault protection is reliable and rapid, and the loss of synchronism generator would be synchronous again by load shedding.

关 键 词：同步发电机 失磁保护 功角保护 功角特性 静态稳定性 动态稳定性 

分 类 号：TM31[电气工程—电机]