电工技术学报2024，Vol.39Issue(5)：1352-1371,20.DOI:10.19595/j.cnki.1000-6753.tces.231310
基于故障安全域的混合级联直流输电系统后续换相失败抑制策略
Subsequent Commutation Failure Suppression Strategy for Hybrid Cascaded HVDC System Based on Fault Security Region
摘要
Abstract
The hybrid cascaded high voltage direct current(HVDC)system combines the advantages of line commutated converter(LCC)and modular multilevel converter(MMC),making it a prominent area of focus in both academic research and engineering applications.When an AC fault occurs in the hybrid cascaded HVDC system,it may lead to the first commutation failure of the LCC converter on the inverter side.During the recovery period of the system after the first commutation failure,significant fluctuations in the electrical quantity on the inverter side and large reactive power demand on the LCC may lead to subsequent commutation failures at the end of the recovery period,seriously endangering the stable operation of the power system.The investigation on hybrid cascaded HVDC system is presently in its initial phases.Current research largely concentrates on investigating the impact of MMC on reactive power support and improving the voltage dependent current order limitation(VDCOL)curve in order to address commutation failures and power recovery,without proposing corresponding coordinated control strategies from the perspective of balancing reactive power interaction and rapid power recovery.There is a lack of safe operating range of the system and in-depth research on the key issue of subsequent commutation failures.Thus,this paper proposes a coordinated control method utilizing MMC and VDCOL to effectively address both the mitigation of subsequent commutation failures and the rapid and stable restoration of power in hybrid cascaded HVDC system. Firstly,the adverse effects of AC bus voltage phase advance on the inverter side during controller interaction and the reactive power demand of the LCC converter during VDOCL operation on system recovery were analyzed.Based on the consideration of the controller and MMC dynamic reactive power support,the fault security region of the hybrid cascaded HVDC system under the coupling of multiple electrical quantities on the inverter side was quantitatively established. Secondly,by comparing and analyzing the fault security region of the hybrid cascaded HVDC system and LCC-HVDC,a coordinated control strategy based on MMC and VDCOL is proposed.While fully utilizing the dynamic reactive power support capability of MMC,the VDCOL curve is adjusted in real-time based on current deviation,achieving coordination between subsequent commutation failure suppression and rapid and stable power recovery of the system. Finally,a simulation comparative analysis was conducted based on PSCAD/EMTDC under different severity AC faults,different short circuit ratios,and different fault durations to verify the effectiveness of the proposed coordinated control strategy and the variation of active power transmitted to the receiving power grid is the main influencing factor for the generation of AC bus voltage phase advance.The simulation results show that compared to the coordinated control strategy without input and the reactive power control strategy with only input,the coordinated control strategy based on MMC and VDCOL proposed in this paper can not only effectively suppress subsequent commutation failures in hybrid cascaded HVDC system,but also achieve fast and stable power recovery,reduce the fluctuation of various electrical quantities during system faults,and accelerate the recovery process of the system.The increase of active power can be up to 109.61%under severe faults,which has obvious advantages and certain engineering application values.关键词
混合级联直流输电系统/后续换相失败/故障恢复期间/故障安全域/协调控制策略Key words
Hybrid cascaded HVDC system/subsequent commutation failure/fault recovery period/fault security region/corrdinated control strategy分类
信息技术与安全科学引用本文复制引用
王鹤,郭家治,边竞,李国庆,王拓..基于故障安全域的混合级联直流输电系统后续换相失败抑制策略[J].电工技术学报,2024,39(5):1352-1371,20.基金项目
国家自然科学基金资助项目(52207077). （52207077）
