660 MW汽轮发电机失磁后稳态异步运行过程分析

某电厂660 MW汽轮发电机因失磁故障进入稳定异步运行，发电机的机端参数和阻抗轨迹呈现有规律的振荡。分析了事故中发电机失磁后进入异步运行的过程。并针对这起事故，采用Matlab建立仿真模型，研究了大型火电机组中励磁回路的结构、发电机失磁前所带的负载、发电机的转动惯量以及发电机铁芯的空载特性4个因素对发电机失磁过程的影响。仿真结果和实际案例较为一致，说明了仿真模型的正确性。仿真结果对大型发电机组的失磁保护有一定的参考意义。

Analysis of stable asynchronous running of 660 MW turbine generator for loss of excitation

A 660 MW turbine generator entered a stable asynchronous running state due to loss of excitation and the generator''s parameters and impedance trajectories showed regular oscillations. This paper analyzes the above process. According to the accident, a simulation model is built using Matlab to study the influence of the four factors on the process of loss of excitation, including the structure of the excitation circuit, the load before loss of excitation, the moment of inertia of the generator, and the no-load characteristic of the iron core in large-scale thermal power generating unit. The simulation results are in good agreement with those from actual case, and the correctness of the simulation model is illustrated. Simulation results have some reference significance for the loss of excitation protection of large generating units. This work is supported by Industrial Key Project of Shaanxi Province (No. 2017GY-030).