工程科学与技术2024，Vol.56Issue(2)：80-90,11.DOI:10.15961/j.jsuese.202201392
级联型混合直流与UPFC的柔性潮流协调控制策略
Flexible Power Flow Coordination Control Strategy of Cascaded Hybrid DC and UPFC
摘要
Abstract
The cascaded hybrid DC transmission system offers advantages in restraining commutation failure and transmitting large capacity power.However,when the downside MMC inverter of the cascaded hybrid HVDC employs master-slave control,AC/DC faults or sudden load increases can lead to a current imbalance problem.This results in large-scale power reverse transmission on the AC side and a decrease in voltage support ability.To enhance the stability of the receiving end power grid,this paper introduces a flexible power flow coordination control strategy based on UPFC for cascaded hybrid DC transmission systems.The article investigates the power flow control characteristics of a cascaded hybrid DC system with UPFC connected nearby.To address issues such as inverse power transmission and voltage support stability during faults and large disturbances,the paper proposes a frequency support strategy based on UPFC and a voltage support strategy based on dynamic limiting.This strategy redirects the power disturbance caused by the sending side fault to the UPFC line of the receiving AC system,leveraging UPFC's power compensation ability for coordination.Additionally,the dynamic limiting control strategy enlarges reactive power output capacity.Sub-sequently,the paper establishes a model of the cascaded hybrid DC transmission system with the receiving AC system using PSCAD-EMTDC software.Firstly,the simulation demonstrates the decrease in LCC DC current command value,showing that the coordinated control strategy based on UPFC effectively reduces frequency fluctuations in AC systems and suppresses power backflow phenomena.Secondly,the simulation of a sudden increase in system load verifies that the dynamic limiting control strategy enhances the voltage support capability of MMC for the AC system.Finally,the paper simulates the cascading fault process,revealing that the proposed coordinated control strategy effectively supports sys-tem frequency and voltage.It suppresses power fluctuations,thereby improving the stability of the cascaded hybrid DC system and the receiving power grid.In conclusion,the results demonstrate the effectiveness and feasibility of the flexible power flow coordination control strategy pro-posed in this paper for cascaded hybrid DC and UPFC.关键词
混合直流输电系统/统一潮流控制器(UPFC)/动态限幅/协调控制策略/电压支撑Key words
hybrid DC system/UPFC/dynamic limit/coordinated control strategy/voltage support分类
信息技术与安全科学引用本文复制引用
黑玉鹏,张英敏,李保宏,江琴,张婉欣,张敏,王腾鑫..级联型混合直流与UPFC的柔性潮流协调控制策略[J].工程科学与技术,2024,56(2):80-90,11.基金项目
国家电网总部科技项目(5100-202199274A-0-0-00) （5100-202199274A-0-0-00）
