基于最大调制比的LCC-MMC混合直流交流侧故障控制策略

发布时间：2019-03-02 14:31

【摘要】：对现有常规直流工程进行逆变站柔性化改造,是解决多馈入直流输电系统潜在级联换相失败问题的一个有效方案,改造后的混合直流系统整流站沿用电网换相换流器,逆变站新建模块化多电平换流器。首先对电网换相换流器和模块化多电平换流器(LCC-MMC)混合直流系统的拓扑结构、基本控制方法以及整流站交流侧故障时功率骤降问题进行了阐述。然后,针对上述问题,提出了基于最大调制比的交流侧故障控制策略,在整流站交流侧故障时,该策略能够通过调节逆变站模块化多电平换流器的调制比,维持直流电流的恒定,降低混合直流系统传输有功功率的跌落幅度,从而减小传输功率骤降对逆变站交流系统的冲击。最后,在PSCAD/EMTDC中建立了混合直流输电系统的仿真模型,验证了所提控制策略的有效性。
[Abstract]:The flexible retrofit of conventional DC inverter station is an effective scheme to solve the potential cascade commutation failure problem of multi-feed HVDC transmission system. The retrofitted rectifier station of the hybrid DC system uses the power grid commutation converter, and it is an effective scheme to solve the problem of potential cascade commutation failure of the multi-feed HVDC transmission system. A new modular multilevel converter is built at the inverter station. Firstly, the topology, the basic control method and the power sag of the hybrid DC system of commutation converter and modular multilevel converter (LCC-MMC) in the power grid are described in this paper, as well as the problem of power sag in the AC side of the rectifier station. Then, a fault control strategy for AC side based on the maximum modulation ratio is proposed, which can adjust the modulation ratio of modularized multilevel converter in inverter station when the AC side fault occurs in rectifier station. To keep the DC current constant, the drop amplitude of the transmission active power of the hybrid DC system is reduced, so as to reduce the impact of the sudden drop of the transmission power on the AC system of the inverter station. Finally, the simulation model of hybrid HVDC system is established in PSCAD/EMTDC, and the effectiveness of the proposed control strategy is verified.
【作者单位】：北京四方继保自动化股份有限公司;南方电网科学研究院有限责任公司;
【分类号】：TM721.1

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