中小型发电机失磁保护研究

Research of excitation-loss protection for medium and small generators

目前,中小型发电机失磁保护方案存在2类典型的缺陷,一种是保护方案的判据过于简单,造成保护容易不正确动作;另一种是保护方案的判据不合理,保护方案不灵活,不能专门针对中小型发电机失磁保护的特点。提出了一种综合微机型失磁保护方案,该方案以现有失磁保护判据为基础,其相关保护判据可以很灵活地投入和退出,保护方案能够对不同发电机因失磁故障可能出现的不同情况灵活地调整出口方式,适合于100MW及其以下各种容量的汽轮发电机和水轮发电机。经动态模拟试验以及现场运行情况表明,该方案提高了保护装置的可靠性。

There are two typical defects in the excitation-loss protection for medium and small generators：the criterion is so simple that the protection will not act correctly;the scheme is not specially for the excitation-loss protection of medium and small generators with its criteria unreasonable and inflexible. A synthetical microprocessor-based excitation- loss protection scheme is presented. Its protection criteria,which are based on the existing criteria,can be flexibly enabled and disabled,and its output modes can be adjusted according to different conditions of excitation- loss faults. The scheme is suitable for 100 MW generators and below. The dynamic simulation and site operation show that the scheme improves protection reliability.