大规模风电接入的特高压混合级联直流系统送端频率控制策略  

Frequency Control Strategy for Sending-End of Hybrid Cascaded UHVDC System Interconnceted with Large-Scale Wind Power

作　　者：李昊 赵成勇 熊小玲 LI Hao;ZHAO Chengyong;XIONG Xiaoing(State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources,North China Electric Power University,Beijing 102206,China)

机构地区：[1]新能源电力系统国家重点实验室(华北电力大学),北京102206

出　　处：《南方电网技术》2023年第11期10-21,共12页Southern Power System Technology

基　　金：国家自然科学基金面上项目(52277176)。

摘　　要：针对特高压混合直流系统的送端电网由于高比例风电接入带来的频率易越限的问题,提出了风电与混合直流系统协调参与的送端电网频率控制策略。首先,介绍了混合直流系统的拓扑,其中送、受端均采用电网换相换流器串联模块化多电平换流器的结构;其次,分别在风机和传统直流换流站中引入考虑一次调频特性与惯性特性的附加频率控制策略,在柔性直流换流站中引入虚拟惯性控制策略;设计了风电与混合直流系统各站协调参与送端电网调频的时序动作规则与各换流站之间的电压协调策略;同时,基于风电与直流并网系统的频率响应模型,定性分析了风电与混合直流系统参与调频的机理,提出了相关控制参数的设计方法;最后,通过PSCAD/EMTDC中建立模型进行仿真验证。仿真结果表明所提频率协调控制策略可以提高送端系统的惯量与一次调频能力,有效改善交流系统在不同运行工况下的频率稳定问题。Aiming at the frequency out-of-limit problem caused by the high proportion of wind power in the power grid at the sending-end of hybrid ultra-high voltage direct current(UHVDC)system,the coordinated frequency control strategy of power grid at the sending-end by wind power and hybrid DC system is proposed.Firstly,the topology of hybrid DC system is introduced,in which the structure of the line commuted converter in series with modular multilevel converter is adopted at the sending and receiving ends;Secondly,the additional frequency control strategy considering primary frequency and inertia characteristics is introduced in the wind turbines and the line commuted converter station respectively,and the virtual inertia control strategy is introduced in the voltage source converter(VSC)station;The timing action rules of wind power and hybrid DC system coordinating and participating in power grid frequency control and the voltage coordination strategy between converter stations are designed;At the same time,the mechanism of wind power and hybrid DC system in frequency control is qualitatively analyzed based on the frequency response model of wind power and DC integrated system,and design method of related control parameters is put forward.Finally,a model is built in PSCAD/EMTDC for simulation verification.The simulation results show that the proposed frequency coordinated control strategy can improve the inertia and primary frequency capability of the sending-end system and effectively improve the frequency stability problem of the AC system under different operating conditions.

关 键 词：新能源 混合特高压直流系统 频率控制策略 惯量 一次调频 

分 类 号：TM721.1[电气工程—电力系统及自动化]