联接弱交流电网MMC-HVDC系统的直流功率传输能力提升方法  

An Improvement Method of DC Power Transmission Capability for MMC-HVDC System Integrated to Weak AC Grid

作　　者：郭春义[1] 林欣 王燕宁 杨硕 赵成勇[1] GUO Chunyi;LIN Xin;WANG Yanning;YANG Shuo;ZHAO Chengyong(School of Electrical and Electronic Engineering,North China Electric Power University,Beijing 102206,China;State Grid Shanghai Songjiang Electric Power Supply Company,Shanghai 201600,China)

机构地区：[1]华北电力大学电气与电子工程学院,北京102206 [2]国网上海市电力公司松江供电公司,上海201600

出　　处：《华北电力大学学报（自然科学版）》2023年第4期10-19,29,共11页Journal of North China Electric Power University：Natural Science Edition

基　　金：国家自然科学基金资助项目(51877077)。

摘　　要：模块化多电平换流器高压直流输电(modular multilevel converter based high voltage direct current,MMC-HVDC)由于具备自换相能力,尤其适用于向弱交流电网供电。交流系统强度降低时,会制约系统的直流功率传输能力,甚至导致系统失稳。针对联接弱交流电网时MMC-HVDC系统功率传输受限的问题,建立了状态空间与直流阻抗模型,从时域、频域两方面研究了交流系统强度对直流功率传输能力的影响,明确了弱交流电网工况下功率传输受限的原因。基于参与因子定位结果,提出了在定直流电压控制环节引入直流电流反馈的功率传输能力提升方法,从时域、频域两方面对控制策略的提升作用进行了机理分析,并定量得出了控制参数的可行域及功率传输能力的最大提升水平。该方法在避免稳态误差的前提下,有效提升了MMC-HVDC系统的直流功率传输能力。Modular multilevel converter based high voltage direct current(MMC-HVDC)is especially suitable for supplying power to weak AC grid due to its self-commutation capability.When the strength of the AC system is reduced,it will restrict the DC power transmission capacity of the system,and even lead to instability.Aiming at the problem of limited power transmission of MMC-HVDC system integrated to weak AC grid,we established a state-space and DC impedance model and studied the influence of strength of AC grid on DC power transmission capability from both time-domain and frequency-domain to reveal the reason for the limited power transmission under weak AC grid conditions.An improvement method of power transmission capability with DC current feedback introduced in the constant DC voltage control link was proposed based on the results of participation factors.We analyzed the mechanism of improving the control strategy from both time-domain and frequency-domain,respectively,and obtained the feasible range of control parameters and the maximum improvement level of power transmission capability quantitatively.This method effectively improves the DC power transmission capability of MMC-HVDC system while avoiding steady-state errors.

关 键 词：模块化多电平换流器 状态空间模型 直流阻抗模型 功率传输能力 附加阻尼控制 弱交流电网 

分 类 号：TM721.1[电气工程—电力系统及自动化]