Quantitative Assessment for Commutation Security Based on Extinction Angle Trajectory

Qi, Tao; Xue, Yusheng

doi:10.35833/mpce.2019.000239

Cited by 7 publications

(2 citation statements)

References 17 publications

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“…Yet, the commutation failure (CF) is an adverse and frequent phenomenon at the inverter side of LCC-HVDC system under the fault conditions [4]. The subsequent CF may easily occur if the first CF is not handled timely and correctly, which will result in the power outage and greatly affect the safe and stable operation of power grids [5], [6].…”

Section: Introductionmentioning

confidence: 99%

Commutation Failure Mitigation Method Based on Imaginary Commutation Process

Zhou

Xia

Hong

et al. 2022

Journal of Modern Power Systems and Clean Energy

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The commutation failure (CF) mitigation effectiveness is normally restricted by the delay of extinction angle (EA) measurement or the errors of existing prediction methods for EA or firing angle (FA). For this purpose, this paper proposes a CF mitigation method based on the imaginary commutation process. For each sample point, an imaginary commutation process is constructed to simulate the actual commutation process. Then, the imaginary EA is calculated by comparing the imaginary supply voltage-time area and the imaginary demand voltage-time area, which can update the imaginary EA earlier than the measured EA. In addition, the proposed method considers the impacts of commutation voltage variation, DC current variation, and phase angle shift of commutation voltage on the commutation process, which can ensure a more accurate EA calculation. Moreover, the DC current prediction is proposed to improve the CF mitigation performance under the single-phase AC faults. Finally, the simulation results based on CIGRE model prove that the proposed method has a good performance in CF mitigation.

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Section: Introductionmentioning

confidence: 99%

Commutation Failure Mitigation Method Based on Imaginary Commutation Process

Zhou

Xia

Hong

et al. 2022

Journal of Modern Power Systems and Clean Energy

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“…The essential reason for CF is that the extinction angle is smaller than the critical extinction angle [8]. In conventional wisdom, the critical extinction angle is universally set to be 7°or 10° [9].…”

Section: Introductionmentioning

confidence: 99%

Improved Identification Method and Fault Current Limiting Strategy for Commutation Failure in LCC-HVDC

Liu

Lin

Zhong

et al. 2022

Journal of Modern Power Systems and Clean Energy

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Line-commutated converter based high-voltage direct-current (LCC-HVDC) transmission systems are prone to subsequent commutation failure (SCF), which consequently leads to the forced blocking of HVDC links, affecting the operation of the power system. An accurate commutation failure (CF) identification is fairly vital to the prevention of SCF. However, the existing CF identification methods cause CF misjudge or detection lag, which can limit the effect of SCF mitigation strategy. In addition, earlier approaches to suppress SCF do not clarify the key factor that determines the evolution of extinction angle during system recovery and neglect the influence. Hence, this paper firstly analyzes the normal commutation process and CF feature based on the evolution topology of converter valve conduction in detail. Secondly, the energy in the leakage inductance of converter transformer is presented to characterize the commutation state of the valves. Then a CF identification method is proposed utilizing the leakage inductance energy. Thirdly, taking the key variable which is crucial to the tendency of extinction angle during the recovery process into account, a fault current limiting strategy for SCF mitigation is put forward. Compared with the original methods, the proposed methods have a better performance in CF identification and mitigation in terms of detection accuracy and mitigation effect. Finally, case study on PSCAD/EMTDC validates the proposed methods.

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