发电机励磁调节器低励限制协调控制分析

Analysis on Coordinated Control of Under-Excitation Limiter of Generator Excitation Regulator

从原理上分析了低励限制器(under excitation limiter,UEL)参数整定不当导致系统阻尼弱化的原因,指出了UEL提供的电磁转矩在Δω方向的分量滞后Δω180°,以及UEL的作用频段与PSS配合不当是产生机组阻尼弱化现象的主要原因,并在PSS/E和Matlab仿真软件中建立了单机-无穷大系统的励磁控制系统自定义模型,通过仿真验证了理论分析结论。仿真结果进一步表明UEL提供负阻尼转矩时,低励稳定曲线斜率越低,UEL的作用频段越低,系统时域动态响应特性越好。

The reason of weakening system damping due to inappropriate setting of under excitation limiter （UEL） was analyzed, and it was pointed out that the component of electromagnetic torque provided by UEL, which was lagged behind Ao~ by 180~ in the direction of A 6o, and the improper matching of the acting frequency band of UEL with power system stabilizer （PSS） were the main reason leading to the weakening of unit damping; and using simulation software PSS/E and Matlab a user defined model of excitation control system for single-machine infinite-bus system was built and the results of theoretical analysis were verified by simulation results. It was further proved by simulation results that when negative damping torque was provided by UEL, the smaller the slope of stability curve of under-excitation and the lower the acting frequency band of UEL, the better the time-domain dynamic response of the excitation system would be.