针对异步联网运行后,高水电占比多直流外送云南电网面临的频率失稳风险,采用直流频率限制器(frequency limit controller,FLC)进行故障调频提高系统频率稳定性.分析了 FLC对送端电网系统频率稳定性的提升作用机理,提出了反向频差复归模型的控制逻辑和参数整定方法.为提高FLC的调制效果,通过控制变量仿真分析各环节不同参数对FLC性能的影响,得到±800 kV特高压多端混合直流FLC参数的建议值,即频率死区为0.15 Hz,输出限幅值分别为+20％和-50％,比例环节系数为30,积分环节系数为22.2.采用BPA(Bonneville Power Administration)仿真分析有无FLC功能下的系统响应情况,验证了所提FLC配置方案对提高系统频率稳定性的有效性.可为特高压多端混合直流工程相关调制功能的定值整定提供重要参考和指导.
±800 kV UHV multi-terminal hybrid DC frequency limit controller and parameter adjustment
To address the risk of frequency instability faced by Yunnan power grid with high hydropower ratio and multiple direct current(DC)outgoing transmissions after asynchronous network operation,a DC frequency limit controller(FLC)is used for fault frequency modulation to improve the frequency stability of the system.The mechanism of FLC effect on improving the frequency stability of the sending end grid system is analyzed,and the control logic and parameter adjustment method of the inverse frequency difference reversion model are proposed.In order to improve the modulation effect of FLC,the suggested values of FLC parameters for±800 kV ultra-high voltage(UHV)multi-terminal hybrid DC are obtained by analyzing the effect of different parameters of each link on FLC performance through control variable simulation.The frequency dead band is 0.15 Hz,the output limit values are+20％and-50％,respectively.The proportional link coefficient is 30,and the integral link coefficient is 22.2.The BPA(Bonneville Power Administration)simulation is used to analyze the system response with or without FLC function,and the effectiveness of the proposed FLC configuration scheme to improve the system frequency stability is verified.It can provide important reference and guidance for the calibration of the relevant modulation functions in UHV multi-terminal hybrid DC projects.
UHV multi-terminal hybrid DCDC frequency limit controllersystem frequency stabilityparameter adjustmentsending end grid
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