An Equivalent Calculation Method for Pole-to-Ground Fault Transient Characteristics of Symmetrical Monopolar MMC Based DC Grid

Yu, Jingqiu; Zhang, Zheren; Xu, Zheng; Wang, Guoteng

doi:10.1109/access.2020.3006028

Cited by 15 publications

(12 citation statements)

References 27 publications

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“…Simplified RL series representation of DC lines has been proved to have sufficient accuracy in [19][20][21] and is also -7…”

Section: Calculation For the Objectivesmentioning

confidence: 99%

“…Simplified RL series representation of DC lines has been proved to have sufficient accuracy in [19][20][21] and is also -203 adopted in this study. MMCs could be equivalent to RLC series circuits in parallel with a variable dc current source, which are suitable for transient calculation under various faults, as shown in Figure 10.…”

Section: Calculation For the Objectivesmentioning

confidence: 99%

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Hybrid HVDC circuit breakers with an energy absorption branch of a parallel arrester structure

Zhang

et al. 2021

High Voltage

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Hybrid circuit breakers (CBs) are the most promising technology to isolate DC faults in modular multilevel converter (MMC)-based DC grids. However, they consist of expensive power electronic components that are sensitive to high overvoltage and overcurrent. This study proposes a hybrid high-voltage DC circuit breaker with an energy absorption branch of a parallel arrester structure, and investigates the possibility of reducing the fault current and the switching overvoltage. First, the basic principle of an energy absorption branch with a parallel arrester structure is presented. Then, the simultaneous and sequential insertion strategies are illustrated. Second, each strategy and each structure are combined separately to analyse their respective characteristics in reducing the overvoltage, the fault current, the energy absorption and the fault clearance time. The sequential insertion strategy of the proposed energy absorption branch is proved to have the best performance. Finally, the trade-offs between these four metrics are achieved through the non-dominated sorting genetic algorithm II (NSGA-II). A general method to determine the parameters of the proposed energy absorption branch from the Pareto front based on different preferences is provided. Simulations on PSCAD show that sequential insertion of the proposed energy absorption branch with the optimal parameters is able to suppress the switching overvoltage and limit the fault current to a relatively low extent simultaneously.This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.

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“…Simplified RL series representation of DC lines has been proved to have sufficient accuracy in [19][20][21] and is also -7…”

Section: Calculation For the Objectivesmentioning

confidence: 99%

Section: Calculation For the Objectivesmentioning

confidence: 99%

Hybrid HVDC circuit breakers with an energy absorption branch of a parallel arrester structure

Zhang

et al. 2021

High Voltage

Self Cite

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“…The main reason is that renewable energy to access power systems is becoming increasingly complicated in recent years, and fault analysis has to accord with the requirements of sensitivity, fast, and accurate at the same time (Liao et al, 2018;Zhu et al, 2019;Liu et al, 2020a;Zhu et al, 2020;Wang et al, 2021). These problems have been solved based on transient analysis, showing practical application (Saleh et al, 2015;Yu et al, 2020). In addition, the demand for data is urgent with the rapid development of deep learning technology in power systems (Yang et al, 2018;Yang et al, 2021b).…”

Section: Introductionmentioning

confidence: 99%

A Fault Signal Processing Method Based on An Improved Prony Algorithm

et al. 2022

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The fault of power systems introduces a severe challenge in terms of fault recording analysis, and the traditional Prony method cannot perform satisfactorily in the process of signal recordings fitting caused by faults. Therefore, an improved adaptive Prony algorithm is proposed in this article to study the characteristics of fault recordings. Specifically, the search step size is taken as an adaptive variable, and the mean square relative fitting error (MSRFE) is set as the criterion. Then, a large step is employed to rapidly determine an approximate segmentation point in the initial stage of the searching process, and its horizon is gradually reduced to establish an accurate subsegment point. Finally, the Prony algorithm is deployed to analyze the subsegment fitting original signal. The proposed approach has been simulated on an assumed fault signal, and the results validate the accuracy and efficiency of the method.

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“…Fault analysis is the basis of protection research for VSC-based DC distribution networks. It determines the design of the protection scheme and selection of power electronic devices [6]. Bipolar shortcircuit faults are the most severe fault type for DC distribution networks.…”

Section: Introductionmentioning

confidence: 99%

Contribution Mechanism and Impact Analysis of AC System at the Diode Natural Commutation and Conduction Stage During Bipolar Short-Circuit Fault for Single-Terminal VSC-Based DC Distribution Networks

Zhang

Wang

et al. 2022

IEEE Access

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For single-terminal voltage source converter (VSC)-based DC distribution networks, the characteristics of bipolar short-circuit faults are a key factor for the design of protection schemes and the selection of power electronic devices. However, the contribution of AC systems is usually ignored at the diode natural commutation and conduction stage. There is no precise mathematical analysis model for this stage, and no influence mechanism of AC system has been demonstrated from theoretical perspective. This article presents a fault analysis model of the diode natural commutation and conduction stage, focusing on the transient feeding process of VSC converter during the bipolar short-circuit fault for single-terminal VSC-based DC distribution networks. According to equivalent circuits of different transient substages, accurate mathematical state equations are established. Expressions of each electrical fault variation during different substages are provided. A precise mathematical model is constructed, which considers the contribution mechanism of AC system at this stage. Then, based on this mathematical model, the influence of the AC system on electrical fault variations is analyzed from a theoretical perspective. The analysis results show that the influence is always small under different conditions and that ignoring the contribution of AC system can still meet actual engineering needs. A simulation model is constructed using MATLAB/Simulink software. The simulation results validate the effectiveness and superiority of the analysis model. INDEX TERMSVoltage source converter, Single-terminal, Bipolar short circuit, Diodes natural commutation and conduction stage, Contribution mechanism, Impact analysis. Nomenclature ( ) ( ) ( ) , ,

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An Equivalent Calculation Method for Pole-to-Ground Fault Transient Characteristics of Symmetrical Monopolar MMC Based DC Grid

Cited by 15 publications

References 27 publications

Hybrid HVDC circuit breakers with an energy absorption branch of a parallel arrester structure

Hybrid HVDC circuit breakers with an energy absorption branch of a parallel arrester structure

A Fault Signal Processing Method Based on An Improved Prony Algorithm

Contribution Mechanism and Impact Analysis of AC System at the Diode Natural Commutation and Conduction Stage During Bipolar Short-Circuit Fault for Single-Terminal VSC-Based DC Distribution Networks

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