云南异步电网中频率振荡的分段线性模型分析方法

Analysis Method of Piecewise Linear Model for Frequency Oscillation in Asynchronous Power Grid of Yunnan in China

云南异步联网试验中部分频率振荡现象发生在调速器死区附近,为分析此问题,文中建立了考虑调速器死区的分段线性系统模型。通过稳态和动态行为分析阐明了调速器死区对频率稳定性的影响。研究结果表明,增强型死区可能导致系统不存在平衡点,引起频率在死区附近振荡;同时分段线性化系统的稳定性由各频率区间对应的线性系统特征值决定,系统的负阻尼效应也会导致频率失稳,采用简化系统模型和云南电网实际模型均能仿真再现试验中的不同频率振荡现象。

Some frequency oscillations occurred near the governor dead band in the test of asynchronous interconnection in Yunnan in China. To analyze this issue, a piecewise linear system model considering governor dead band is established. The effect of governor dead band on frequency stability is clarified through steady-state and dynamic behavior analysis. Research results show that the system may have no equilibrium point with step-response dead band and it will cause frequency oscillations near the dead band. Meanwhile, the stability of piecewise linear system is determined by the eigenvalue of the linear system corresponding to each frequency range, and the negative damping effect can also cause system frequency instability. Different frequency oscillations in the test are simulated by both the simplified system model and the actual model of Yunnan power grid.