Internal converter- and DC-fault handling for a single point grounded bipolar MMC-HVDC system

Wenig, Simon; Goertz, Max; Heinisch, M.; Beckler, S.; Kahl, Matthias; Suriyah, Michael; Christian, Jochen

doi:10.1016/j.epsr.2018.04.012

Cited by 6 publications

(3 citation statements)

References 15 publications

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“…This aspect changes for bipolar schemes equipped with FBs, as advanced controls enable a control‐wise current interruption during dc side contingencies. As mentioned in [3], STATCOM functionality (reactive current capability) can be maintained.…”

Section: Bipolar Mmc‐hvdcmentioning

confidence: 99%

“…This avoids blocking (converter passivation) and enables continuing in‐feed of reactive power (STATCOM) into the connected ac network. To supplement available literature mainly dealing with dc fault current interruption (FCI) and restart procedures [2, 3], this work focuses on protection scheme design and threshold determination to obtain high selectivity.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Fault discrimination and protection coordination for a bipolar full‐bridge MMC‐HVDC scheme

Wenig

Goertz

Heinisch

et al. 2018

J. eng.

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Section: Bipolar Mmc‐hvdcmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Fault discrimination and protection coordination for a bipolar full‐bridge MMC‐HVDC scheme

Wenig

Goertz

Heinisch

et al. 2018

J. eng.

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“…Another alternative approach is using modified MMC topologies with DC fault handling capability [19]. These topologies include the full bridge submodule (FBSM) [4], [20]- [21], clamp double submodule (CDSM) [22], selfblocking sub-module (SBSM) [23], and diode-clamped submodule (DCSM) [24]. FBSM can extinguish fault current in any direction by blocking all insulated-gate bipolar transistors (IGBTs).…”

Section: Introductionmentioning

confidence: 99%

A Bypass LCC-Based DC Fault Isolation Scheme for Bipolar MMC–HVDC

et al. 2019

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This paper proposes a topology that can quickly eliminate DC short-circuit faults for a bipolar modular-multilevel-converter based high-voltage direct-current (MMC-HVDC) transmission. The additional thyristors are augmented to each half-bridge submodule, which will be reconfigured to form a bypass line commutated converter (LCC). The bypass LCC can be paralleled with one pole of bipolar MMC-HVDC through a hybrid switch, and MMC can be switched to the bypass LCC during the DC fault. The bypass LCC is used to eliminate the DC fault given its ability to output an inverse voltage. The tripped sequence of the hybrid switch is designed and the corresponding equivalent circuits during different stages are analyzed. Afterward, the expressions of the DC fault current in different stages are deduced by the equivalent circuits. The firing angle of the bypass LCC and the conduction resistance of the hybrid switch MOA are then designed. The additional cost and power loss of the proposed scheme are compared with those of other DC fault isolation schemes. The simulation results of the DC fault case obtained by PSCAD/EMTDC are used to verify the effectiveness of the proposed scheme.INDEX TERMS MMC-HVDC, bypass LCC, pole-to-pole DC fault, isolation, hybrid switch.

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Analysis and Protection Scheme of Station Internal AC Grounding Faults in a Bipolar MMC-HVDC System

Xue

Liu

et al. 2020

IEEE Access

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The symmetrical bipolar configuration shows a great advantage in modular multilevel converter (MMC) based high-voltage dc-current (HVDC) transmission. In a bipolar MMC-HVDC system, station internal ac grounding faults cause sub-module (SM) capacitors to discharge violently. These faults do great harm to MMCs and require special protection schemes. In this paper, a single-phase-to-ground fault is taken as an example to investigate transient characteristics of station internal ac grounding faults in a bipolar MMC-HVDC system. A calculation theory of fault current based on the improving RLC model and second-order differential equation with variable coefficients is introduced. A novel transient zero-mode current based protection criterion with better reliability, quickness, and ability to endure fault resistances is proposed to detect internal ac grounding faults. The fault clearing strategy applicable to three types of grounding faults is also designed. The correctness of the proposed calculation theory and protection schemes is verified through simulations performed in PSCAD/EMTDC. INDEX TERMS MMC-HVDC, station internal ac grounding fault, second-order differential equation with variable coefficients, transient zero-mode current, protection scheme.

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Internal converter- and DC-fault handling for a single point grounded bipolar MMC-HVDC system

Cited by 6 publications

References 15 publications

Fault discrimination and protection coordination for a bipolar full‐bridge MMC‐HVDC scheme

Fault discrimination and protection coordination for a bipolar full‐bridge MMC‐HVDC scheme

A Bypass LCC-Based DC Fault Isolation Scheme for Bipolar MMC–HVDC

Analysis and Protection Scheme of Station Internal AC Grounding Faults in a Bipolar MMC-HVDC System

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