Active control of DC fault currents in DC solid-state transformers during ride-through operation of multi-terminal HVDC systems

Li, Rui and Xu, Lie and Yao, Liangzhong and Williams, Barry (2016) Active control of DC fault currents in DC solid-state transformers during ride-through operation of multi-terminal HVDC systems. IEEE Transactions on Energy Conversion. ISSN 0885-8969 (https://doi.org/10.1109/TEC.2016.2575139)

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Abstract

When a pole-to-pole dc fault occurs in a multi-terminal HVDC system, it is desirable that the stations and dc solid-state transformers on healthy cables continue contributing to power transfer, rather than blocking. To reduce the fault current of a modular multilevel converter based dc solid-state transformer, active fault current control is proposed, where the dc and ac components of fault arm currents are regulated independently. By dynamically regulating the dc offset of the arm voltage rather than being set at half the rated dc voltage, the dc component in the fault current is reduced significantly. Additionally, reduced ac voltage operation of the dc solid-state transformer during the fault is proposed, where the ac voltage of transformer is actively limited in the controllable range of both converters in the transformer to effectively suppress the ac component of the fault current. The fault arm current peak and the energy absorbed by the surge arrester in the dc circuit breakers are reduced by 31.8% and 4.9% respectively, thereby lowering the capacities of switching devices and circuit breakers. Alternatively, with the same fault current level, the dc-link node inductance can be halved by using the proposed control, yielding lowered cost and volume. The novel active fault current control mechanism and the necessary control strategy are presented and simulation results confirm its feasibility.

ORCID iDs

Li, Rui ORCID logoORCID: https://orcid.org/0000-0001-8990-7546, Xu, Lie ORCID logoORCID: https://orcid.org/0000-0001-5633-7866, Yao, Liangzhong and Williams, Barry;
  • Item type:Article
    ID code:56594
    Dates:
    Date
    Event
    1 June 2016
    Published
    1 June 2016
    Published Online
    30 May 2016
    Accepted
    Notes:(c) 2016 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting/ republishing this material for advertising or promotional purposes, creating new collective works for resale or redistribution to servers or lists, or reuse of any copyrighted components of this work in other works.
    Subjects:Technology > Engineering (General). Civil engineering (General)
    Department:Faculty of Engineering > Electronic and Electrical Engineering
    Depositing user: Pure Administrator
    Date deposited:03 Jun 2016 10:48
    Last modified:11 Nov 2024 11:26
    URI:https://strathprints.strath.ac.uk/id/eprint/56594
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