Mechanism and Prevention of Commutation Failure in LCC-HVDC Caused by Sending End AC Faults

Earlier works have reported that rectifier AC faults also can cause commutation failure during fault‐off recovery process. Whereas the occurrence of CF is merely ascribed to inverter AC faults in conventional wisdom. Note that the existing CF mitigation approaches are designed mostly by the evolution of inverter electrical quantities, which will fail to take action to CF caused by rectifier faults, posing threat to the operation of power system. Thus, the paper firstly presents the essential reasons for CF caused by rectifier ac faults, combined with the fault information transmission process and control response. It is found that DC current surge and improper control interaction are the main reasons. Accordingly, a novel current cooperative optimization (CCO) control strategy is proposed, which aimed at reducing the risk of CF caused by rectifier ac faults. Simulation results verify the correctness of the mechanism and the effectiveness of the proposed control strategy.

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“…Then, the mechanism was analysed further in Ref. [5], finding that the surge of DC current is also the main reason. Based on this, Ref.…”

Section: Literature Surveymentioning

confidence: 99%

Analysis and prevention of commutation failure caused by HVDC rectifier AC faults

Lin

Lei

Liu

et al. 2022

IET Generation Trans & Dist

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“…Ultra-HVDC (UHVDC) transmission technology has been extensively utilized around the world due to its well-known advantage of long-distance bulk power transmission and lower operating power losses [1]. And commutation failure (CF) is a frequent and adverse event in LCC-HVDC systems, usually occurring as the consequence of the short-circuit fault in the AC system on the inverter side [2,3]. Statistics show that a total number of 60 CFs were recorded in East China Power Grid from 2011 to 2018, and up to four HVDC lines suffered from a temporary interruption of the power transmission and misoperation of the protective relays in the severest cases [4,5].…”

Section: Introductionmentioning

confidence: 99%

Interaction Mechanism and Coordinated Control of Commutation Failure Prevention in Multi-Infeed Ultra-HVDC System

Yao

Wang

Xiong

et al. 2022

International Transactions on Electrical Energy Systems

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Commutation failure (CF) is an inherent drawback of line-commutated converter high-voltage DC (LCC-HVDC) system. And CF prevention (CFPREV) control is widely applied in UHVDC lines to mitigate the subsequent CF. However, the formation of a multi-infeed UHVDC system induces power exchange and voltage interaction between AC buses during the transient process, making the behaviors and mitigation of CFs more complex. Consequently, exploring the impact of CFPREV control on adjacent stations and optimizing the CFPREV control to adapt to the interaction characteristics in a multi-infeed system is necessary. Considering the interaction characteristics, the impact of CFPREV control on the commutation process of inverters in a multi-infeed system is analyzed through formula derivation and simulation verification. It is found that although CFPREV control can effectively mitigate the CFs of the inverter near the fault, it will further increase the risk of concurrent CF (CCF) of remote inverters due to the interaction on the AC side. To solve this problem, a coordinated control scheme of CFPREV controls in a multi-infeed UHVDC system is proposed. The output of the CFPREV control of the inverter near the fault can be adjusted adaptively according to the commutation margins of remote inverters. And the probability of CCF caused by CFPREV control is consequently decreased. Case studies are conducted based on Henan provincial multi-infeed UHVDC system in China to verify the analysis result and the effectiveness of the coordinated control scheme of CFPREV controls.

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“…Commutation failure (CF) is the abnormal behavior of a semi-controlled DC converter valve composed of thyristors. CFs at the DC inverter side threaten the stable operation of the power system (Wang et al, 2019;Hong et al, 2021). If the fault is not cleared in time, it may cause a power outage of the AC system on the inverter side (Xue et al, 2018).…”

Section: Introductionmentioning

confidence: 99%

Transient Stability Analysis of the Two-Area With AC/DC Paralleled Interconnected Power System in Different Operation

et al. 2021

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In order to deeply explore the transient stability mechanism of the AC/DC hybrid system, this paper analyzes the rotor angle stability of the two-area AC/DC hybrid system. The system is analyzed after subjecting it to large disturbances in the AC system and for different operating conditions, qualitatively and quantitatively. The influence of factors, such as the AC operating point of the system and the proportion of DC transmission power, have been considered for improving the rotor motion equation. Subsequently, the transient characteristics of the hybrid system are analyzed after being subjected to disturbances. The power angle stability margin index is obtained, based on which the transient characteristics after DC blocking are analyzed, and the coordinated control strategy with the least control cost is proposed. The results are verified using the two-area AC/DC parallel transmission system network model. The study provides the reference for ensuring the security and stability of the hybrid AC/DC power grid.

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Mechanism and Prevention of Commutation Failure in LCC-HVDC Caused by Sending End AC Faults

Cited by 38 publications

References 6 publications

Analysis and prevention of commutation failure caused by HVDC rectifier AC faults

Analysis and prevention of commutation failure caused by HVDC rectifier AC faults

Interaction Mechanism and Coordinated Control of Commutation Failure Prevention in Multi-Infeed Ultra-HVDC System

Transient Stability Analysis of the Two-Area With AC/DC Paralleled Interconnected Power System in Different Operation

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