Series Capacitor Compensated AC Filterless Flexible LCC HVDC With Enhanced Power Transfer Under Unbalanced Faults

Xue, Ying; Zhang, Xiaoping; Yang, Conghuan

doi:10.1109/tpwrs.2019.2899065

Cited by 36 publications

(15 citation statements)

References 17 publications

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“…Thus, the cost of the proposed converter is substantially reduced compared to the conventional MMC, considering high efficiency of the DR. In addition, the capitalized cost associated with losses is typically in the range of 3000~5000 €/kW [29,30,33,34] and, considering the average value of 4000 €/kW and 26.6% loss reduction of the proposed topology, the cost is further reduced by 10 M€ if the conventional MMC rated at 1200 MW is replaced by the proposed DFB-MMC. Compared to conventional line-commutated converters (LCCs), the size of filters required by the DR in the proposed topology is reduced, leading to lower volume and cost [12,35,36].…”

Section: Comparison Between the Proposed Dfb-mmc And Other Alternamentioning

confidence: 99%

A Unidirectional Hybrid HVDC Transmission System Based on Diode Rectifier and Full-Bridge MMC

2021

IEEE J. Emerg. Sel. Topics Power Electron.

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To reduce the cost of bulk power transmission using voltage source converter HVDC technology, a unidirectional hybrid converter is proposed, where a diode rectifier and a modular multilevel converter (MMC) based on full-bridge (FB) submodules are connected in series on DC side. The FB-MMC controls its DC voltage to regulate the transmitted power. The majority of the power transmission is via the diode rectifier considering its cost and efficiency superiority and only low power rating FB-MMC is required. A thyristor valve is equipped at the DC side of the FB-MMC to prevent potential overcharge of the FB submodules during DC faults. Compared to conventional MMCs, losses can potentially be reduced by around 20%. An active power controller is proposed to regulate the DC voltage of the FB-MMC so as to control the transmitted power. With the inverter station controlling its DC terminal voltage constant, the FB-MMC increases the output DC voltage to increase the transmitted power and, vice versa. To alleviate overvoltage of the HVDC link during AC grid faults of the inverter station, a dynamic DC voltage limiter is designed to actively reduce the DC output voltage of the FB-MMC. Simulation results confirm the proposed converter operation and control. Index Terms-active power control, diode rectifier HVDC (DR-HVDC), fault ride-through, HVDC transmission, full-bridge (FB) based modular multilevel converter (MMC).

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Section: Comparison Between the Proposed Dfb-mmc And Other Alternamentioning

confidence: 99%

A Unidirectional Hybrid HVDC Transmission System Based on Diode Rectifier and Full-Bridge MMC

2021

IEEE J. Emerg. Sel. Topics Power Electron.

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“…13. After the fourth iteration, the updated [ -τ τ]=[0.1480.149] s will cause |τ --τ |/τ 4 cr to be less than ε 1 , then the search process is over. In order to verify the impact of different fault locations on the robustness of the proposed strategy, 30 sets of examples are randomly selected for the above 3 typical parameters (10 sets respectively) in the modified IEEE 39-bus system.…”

Section: ) Fault Clearing Timementioning

confidence: 99%

Quantitative Assessment for Commutation Security Based on Extinction Angle Trajectory

Xue

2021

Journal of Modern Power Systems and Clean Energy

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In order to reduce the risk of commutation failure (CF) in the AC/DC hybrid power system, the quantitative analysis on CF is required for on-line assessment and optimal control. This paper presents an accurate and reliable method to quantify the commutation security based on the trajectory due to the complexity of the high-voltage direct current (HVDC) model. Firstly, the characteristics of the extinction angle trajectory are analyzed under both commutation success and failure conditions. The commutation security margin index (CSMI) is then proposed for the HVDC systems. Moreover, a search strategy for parameter limits is put forward based on the sensitivity analysis of CSMI to accelerate the search speed with a guaranteed accuracy level. A modified IEEE 39-bus power system and an actual large-scale power system with 46 generators and 821 buses are utilized to verify the validity and robustness of the proposed index and strategy.

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“…Line-Commutated Converter based HVDC (LCC-HVDC) technology has been extensively utilized around the world for long-distance bulk-power transmission due to its merits such as the thyristor's superior power handling capability and lower operating power losses [1], [2]. Nevertheless, the development of LCC-HVDC systems suffers from some wellknown challenges such as poor voltage regulation ability and vulnerability to commutation failures during inverter ac fault incidents, which can lead to a temporary cessation of transmitted power, overheating of the valves, and misoperation of the protective relays [3].…”

Section: Introductionmentioning

confidence: 99%

A Controllable Thyristor-Based Commutation Failure Inhibitor for LCC-HVDC Transmission Systems

Mirsaeidi

Tzelepis

et al. 2021

IEEE Trans. Power Electron.

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Commutation failure is a serious malfunction in linecommutated High Voltage Direct Current (HVDC) converters which is mainly caused by the inverter ac faults, and results in a temporary interruption of transmitted power and damage to the converter equipment. In this paper, a Controllable Commutation Failure Inhibitor (CCFI) is developed which obviates the main drawbacks of the existing power-electronic-based and faultcurrent-limiting-based strategies. Under normal circumstances, the developed CCFI improves the steady-state stability and the power transfer capability of the inverter ac lines, while it does not cause excessive voltage stress on the converter valves. In addition, it would reduce the risk of commutation failure occurrence, since it does not lead to any voltage drop in the commutation circuit. When a fault occurs at one of the inverter ac systems, its corresponding CCFI limits the fault current depending on the reduced extinction angle. This would not only inhibit the successive commutation failures on the HVDC converter, but also extend the lifetime of components in the inverter ac systems. The practical feasibility of the developed CCFI is assessed through laboratory testing, using real-time Opal-RT hardware prototyping platform. The obtained results indicate that the developed CCFI can reliably inhibit the commutation failures during various types of faults.

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Series Capacitor Compensated AC Filterless Flexible LCC HVDC With Enhanced Power Transfer Under Unbalanced Faults

Cited by 36 publications

References 17 publications

A Unidirectional Hybrid HVDC Transmission System Based on Diode Rectifier and Full-Bridge MMC

A Unidirectional Hybrid HVDC Transmission System Based on Diode Rectifier and Full-Bridge MMC

Quantitative Assessment for Commutation Security Based on Extinction Angle Trajectory

A Controllable Thyristor-Based Commutation Failure Inhibitor for LCC-HVDC Transmission Systems

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