Impact of strength and proximity of receiving AC systems on cascaded LCC-MMC hybrid HVDC system

He, Yongjie and Xiang, Wang and Ni, Binye and Lu, Xiaojun and Wen, Jinyu (2021) Impact of strength and proximity of receiving AC systems on cascaded LCC-MMC hybrid HVDC system. IEEE Transactions on Power Delivery. ISSN 0885-8977

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    Abstract

    The cascaded hybrid LCC-MMC inverter is considered as a feasible option to mitigate the commutation failure problem of conventional LCC-HVDC while maintaining bulk power transmission capability. However, the coupling between different types of converters may result in instability when the inverter integrates with weak AC systems. This paper establishes a small-signal model of the cascaded LCC-MMC inverter based hybrid HVDC system and validates the model against PSCAD/EMTDC. Through eigenvalue analysis, the impact of the strength and proximity of receiving AC systems on the small-signal stability is investigated, and the stable zone of the strength of receiving AC systems is identified. Besides, a supplementary coupling mitigation control is proposed to tackle the instability problem under weak AC systems integration. Both analytical results and time-domain simulations demonstrate the validity of the supplementary control.

    ORCID iDs

    He, Yongjie, Xiang, Wang ORCID logoORCID: https://orcid.org/0000-0002-4619-5849, Ni, Binye, Lu, Xiaojun and Wen, Jinyu;