摘要
基于构网型新能源的电网换相换流器(LCC)高压直流输电是实现无常规电源支撑的大型新能源基地经济高效送出的一种可能方案。然而,构网型新能源和LCC的功能定位,以及系统的惯量和强度支撑能力是实现这一方案的关键。为此,提出了基于LCC高压直流输电虚拟调速控制的虚拟同步系统方案。利用LCC的触发角控制自由度实现送端孤岛的有功功率控制与交流电压幅值解耦,使风电机组变流器能够运行于基于P/f特性的虚拟同步机(VSG)模式。提出了基于负向功率流等价的虚拟同步系统构建方法,将风力发电机等价为VSG的负向功率虚拟负荷,并将LCC功能等价为负向功率虚拟原动机。基于此设计了LCC虚拟调速控制,实现了送端孤岛的有功平衡和频率控制。从虚拟调速器反馈控制的角度,揭示了系统稳定运行对VSG虚拟惯量的要求和系统关键参数的影响,并给出了设计方法。最后,利用时域仿真验证了所设计系统方案的稳定运行和暂态故障穿越能力。
Line commutated converter(LCC)-high voltage direct current(HVDC)transmission based on grid-forming renewable energy offers a potential scheme to realize the economical and efficient transmission of large-scale renewable energy bases without the support from the conventional power supply.However,the keys to realize the scheme are the functional positioning of gridforming renewable energy and LCC,as well as the inertia and strength support capability of the system.Therefore,a virtual synchronous system(VSS)scheme based on virtual governor control of LCC-HVDC transmission is proposed.The firing angle control freedom of the LCC is utilized to decouple the active power control and AC voltage amplitude at the sending end of islanded grid,enabling converters of wind turbines to operate in a virtual synchronous generator(VSG)mode based on the P/f characteristics.A modeling method for VSS based on negative power flow equivalence is proposed.This method considers the wind turbine as a negative power virtual load for the VSG,while LCC is considered as a negative power virtual prime mover.On this basis,LCC virtual governor control is designed to realize the active power balance and the frequency regulation at the sending end of islanded grid.From the perspective of feedback control of the virtual governor,the requirements of VSG virtual inertia for stable operation of systems and the impacts of the key system parameters are revealed,and the design methodologies are given.Finally,time-domain simulations validate the stable operation and transient fault ride-through ability of the designed system scheme.
作者
王凯伦
宋强
赵彪
刘文华
余占清
曾嵘
WANG Kailun;SONG Qiang;ZHAO Biao;LIU Wenhua;YU Zhanqing;ZENG Rong(Department of Electrical Engineering,Tsinghua University,Beijing 100084,China)
出处
《电力系统自动化》
北大核心
2025年第8期54-65,共12页
Automation of Electric Power Systems
基金
国家重点研发计划资助项目(2023YFB2405900)。
关键词
风电场
电网换相换流器
构网型控制
虚拟调速控制
虚拟同步机
惯量
频率控制
稳定性
wind farm
line commutated converter(LCC)
grid-forming control
virtual governor control
virtual synchronous generator(VSG)
inertia
frequency control
stability
