调速器死区对水电高占比电力系统频率稳定的影响分析

Analysis of Influence of Governor Deadband on Frequency Stability of Power System with High Proportion of Hydropower

云南电网在交流联络线断线后发生了死区附近的频率振荡现象。为此,文中对此现象进行了研究。首先,在单机系统的传递函数中加入调速器死区环节并对死区进行分段建模;然后,对不同扰动下的频率进行解析求解,从数学上解释了含普通型死区的系统相轨迹曲线连续、而含增强型死区的系统相轨迹曲线不连续的原因;接着,通过频率解的特征和稳定点证明了含增强型死区的正阻尼系统在特定扰动下会出现频率振荡的结论,并给出了振荡发生的条件。最后,通过多机系统的数值仿真验证了理论分析的正确性。

The frequency oscillation phenomenon near the deadband occurred in Yunnan power grid of China after the AC tie line was disconnected.To this end,this phenomenon is studied in this paper.Firstly,the governor deadband link is added to the transfer function of the single-machine system,and the deadband is modeled in sections.Secondly,the frequency with different disturbances is calculated analytically,which mathematically explains the reason why the phase trajectory curves of the system with common deadband is continuous,while the phase trajectory curves of the system with enhanced deadband is discontinuous.Thirdly,through the characteristics and stable points of the frequency solution,it is proven that the positive damping system with enhanced dead band will have frequency oscillations with specific disturbance,and the conditions for oscillation are also given.Finally,the correctness of the theoretical analysis is verified by the numerical simulations of a multi-machine system.