异步联网下控制器死区对电网频率影响分析

Analysis of Influence of Controller Dead Zone on Grid Frequency Under Asynchronous Networking

针对云南电网异步联网后超低频振荡问题严重的问题,首先通过特征分析法推出水轮机调速器中水流时间常数与调差系数对系统阻尼比的影响,采用Nyquist方法分析在发电机外部加入FLC环节后增加了系统的稳定裕度,并基于描述函数法研究控制器中死区对系统稳定性的影响;其次,采用4机2区域模型,验证调节控制器参数对抑制系统频率波动的有效性;最后,基于云南电网实际数据,仿真验证了一次调频与FLC协调控制过程,结果显示改变水轮机调速器死区大于FLC死区时,有利于抑制频率的波动。

After the asynchronous interconnection of Yunnan power grid,the problem of ultra-low frequency oscillation is serious.Firstly,the influence of water flow time constant and regulation coefficient on the damping ratio of the hydraulic turbine governor is introduced by the feature analysis method.The Nyquist method is used to analyze the increase of the system stability margin after adding the Frequency Limit Control(FLC)outside the generator.Based on the description function method,the influence of dead zone on the stability of the system is studied.Secondly,the 4-machine 2-area model is used to verify the effectiveness of the adjustment controller parameters to suppress the system frequency fluctuation.Finally,the primary frequency modulation and FLC coordinated control process is verified by simulation based on the actual data of Yunnan power grid.The results show that when changing the dead zone of the hydraulic turbine governor to be larger than the FLC dead zone,it is beneficial to suppress the fluctuation of the frequency.