CAJ | 학술논문

为了降低电网换相高压直流输电(line-commutated- converter high voltage direct current，LCC-HVDC)的换相失败概率，提出一种LCC-HVDC改进拓扑。该拓扑从增大换流阀换相电压的角度出发，在原阀臂中串联接入新型可控子模块，以辅助换相。首先介绍该拓扑中子模块的3种工作状态，并分析子模块开关管的电压和电流。然后设计改进拓扑的控制策略，提出“最优充电初始电压”这一概念，并对其进行优化计算。PSCAD/EMTDC仿真结果表明，该拓扑能灵活切换子模块的工作状态，提高了 LCC-HVDC 防御换相失败的能力；所提出“最优充电初始电压”的优化计算方法效果良好，对该拓扑的换相失败防御能力有进一步的提升作用。
위료강저전망환상고압직류수전(line-commutated- converter high voltage direct current，LCC-HVDC)적환상실패개솔，제출일충LCC-HVDC개진탁복。해탁복종증대환류벌환상전압적각도출발，재원벌비중천련접입신형가공자모괴，이보조환상。수선개소해탁복중자모괴적3충공작상태，병분석자모괴개관관적전압화전류。연후설계개진탁복적공제책략，제출“최우충전초시전압”저일개념，병대기진행우화계산。PSCAD/EMTDC방진결과표명，해탁복능령활절환자모괴적공작상태，제고료 LCC-HVDC 방어환상실패적능력；소제출“최우충전초시전압”적우화계산방법효과량호，대해탁복적환상실패방어능력유진일보적제승작용。
An improved topology was proposed to decrease the commutation failure in Line-Commutated-Converter High Voltage Direct Current (LCC-HVDC). With novel controllable sub-modules inserted into the bridge, the topology assists in commutating from the viewpoint of increasing the commutating voltage. Firstly, the operating modes of sub-module were analyzed, and the operation voltage and current of the sub-module switches were given by theoretical derivation. Additionally, the control strategy was designed, then the concept of optimal initial charging voltage was presented and its calculation method was investigated. The simulation results in PSCAD/EMTDC show that it is flexible to change the sub-module operation modes, and commutation failure is decreased in LCC-HVDC. The proposed calculation method of optimal initial charging voltage proved to be accurate and it can further reduce the possibility of commutation failure.