一种新的柔性直流输电系统远端启动策略

发布时间：2018-05-28 15:41

本文选题：柔性直流输电 + 模块化多电平换流器　；参考：《电力系统自动化》2015年02期

【摘要】：模块化多电平换流器(MMC)的启动是MMC柔性直流输电系统工程应用首先需要面临的问题,针对采用MMC结构的两端或者多端柔性直流输电系统,提出了一种新型的有序解锁启动方法,以减少传统充电方式下换流阀解锁瞬间的直流电压跌落和桥臂电流冲击。该方法在传统不控充电过程后,先解锁定直流电压换流站,再对其他换流站进行远端充电,期间其他换流站的桥臂按其子模块电容电压高低顺序逐步减少投入充电的子模块个数,以此不断抬高子模块电容电压,在电容电压到达一定数值后再解锁换流站。通过理论分析计算了本方法最大的电压跌落,并通过PSCAD/EMTDC仿真验证了该方法的有效性和优越性。此外,新的远端启动控制策略对多端柔性直流系统的定功率换流站启动顺序和启动时刻没有特殊要求,并针对单桥臂进行设计,可以重复应用于各桥臂,因此,其适用于实际工程中的多端柔性直流系统远端启动和交流系统故障造成无源端闭锁后的在线重启动。
[Abstract]:The start-up of modularized multilevel converter (MMC) is the first problem in the engineering application of MMC flexible DC transmission system. A new method of orderly unlocking start-up is proposed for the two ends or multi-terminal flexible HVDC transmission systems with MMC structure. In order to reduce the DC voltage drop and the current impact of the bridge arm at the unlocking moment of the converter valve under the traditional charging mode. After the traditional uncontrolled charging process, the method first unlocks the DC voltage converter station, and then carries on the remote charging to the other converter stations. During the period, the bridge arms of other converter stations gradually reduce the number of submodules put into charge according to the order of capacitor voltage of their sub-modules, thus continuously raising the capacitance voltage of submodules, and then unlocking the converter station after the capacitance voltage reaches a certain value. The maximum voltage drop of this method is calculated by theoretical analysis, and the effectiveness and superiority of the method are verified by PSCAD/EMTDC simulation. In addition, the new remote start control strategy has no special requirements for the starting sequence and starting time of the fixed power converter station of the multi-terminal flexible DC system, and is designed for the single axle arm, which can be repeatedly applied to each bridge arm. It is suitable for the remote startup of multi-terminal flexible DC system and the on-line reboot caused by the failure of the AC system due to the locking of the passive end in practical engineering.
【作者单位】：国网浙江省电力公司电力科学研究院;浙江大学电气工程学院;
【分类号】：TM721.1

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