Commutation Failure Mitigation Method Based on Imaginary Commutation Process

Zhou, Xiaoping; Xia, Haitao; Hong, Lerong; Yin, Hong; Deng, Liya; Liu, Yifeng

doi:10.35833/mpce.2021.000611

Cited by 14 publications

(9 citation statements)

References 14 publications

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“…To illustrate the suppression effect of the proposed control on CCF in TPG and SPG faults, it is compared with the CIGRE control (Figure 2), the classical CFRPEV control in [16], and the control in [37]. Ref.…”

Section: Simulations and Discussionmentioning

confidence: 99%

“…Usually the simulation step is set as 10, 20, 30, …, and up to 100 µs, and the control step is larger than the former. For example, in [16], the simulation step is 20 µs, and the control step is 100 µs. In [20], the simulation step is 50 µs, and the control step is 70 µs.…”

Section: Study System Descriptionmentioning

confidence: 99%

“…are classified by, (1) applying the var compensators [12,13], (2) modifying the HVDC topology [14,15], and (3) improving the control strategy [16,17]. The latter, has lower cost, and is easier for application.…”

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confidence: 99%

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Suppression to concurrent commutation failure of UHVDC with hierarchical connection mode based on improved dc current prediction

2023

IET Generation Trans & Dist

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For the ultra high‐voltage dc (UHVDC) transmission with hierarchical connection mode (HCM) at the inverter side, local commutation failure (LCF) at one layer after the ac fault may cause concurrent commutation failure (CCF) at the non‐fault layer. The inter‐layer couplings at the ac and dc sides add the difficulty to suppress the CCF. The fault instant may decide the dc current variation during the commutation, which affects the suppression effect. This paper shows the mechanism of the CCF including the inter‐layer ac and dc coupling, and proposes a control method for the inverter at the fault and non‐fault layers. First, an analytical expression among the dc current, ac voltage, and extinction angle of both layers is newly derived to find the dominant factors to the CCF. Second, to improve the calculation accuracy, a three‐point sampling function using Newton interpolation is newly proposed to predict the dc current. Finally, a coordinated control strategy based on the constant extinction area, the overlap‐arc area, and the dominant factor of the CCF is proposed to adjust the firing angle and suppress the CCF. The simulation results using the PSCAD/EMTDC software are given to verify the control effect of the proposed method against the CCF.

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Section: Simulations and Discussionmentioning

confidence: 99%

Section: Study System Descriptionmentioning

confidence: 99%

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Suppression to concurrent commutation failure of UHVDC with hierarchical connection mode based on improved dc current prediction

2023

IET Generation Trans & Dist

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“…The imaginary commutation process [17] starts at t s and ends at t e , as shown in Fig. 2, where α i ( ) t s is the FA at t s ; ω is the angular frequency; γ iIm ( ) t e and A γiIm ( ) t e are the imaginary EA and imaginary deionization area at t e , respectively; and A γiN is the rated value of the imaginary deionization area.…”

Section: B Calculation Of Second DC Current Ordermentioning

confidence: 99%

DC Current Order Optimization Based Strategy for Recovery Performance Improvement of LCC-HVDC Transmission Systems

Zhou

Luo

Hong

et al. 2023

Journal of Modern Power Systems and Clean Energy

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For the safe and fast recovery of line commutated converter based high-voltage direct current (LCC-HVDC) transmission systems after faults, a DC current order optimization based strategy is proposed. Considering the constraint of electric and control quantities, the DC current order with the maximum active power transfer is calculated by Thevenin equivalent parameters (TEPs) and quasi-state equations of LCC-HVDC transmission systems. Meanwhile, to mitigate the subsequent commutation failures (SCFs) that may come with the fault recovery process, the maximum DC current order that avoids SCFs is calculated through imaginary commutation process. Finally, the minimum value of the two DC current orders is sent to the control system. Simulation results based on PSCAD/EMT-DC show that the proposed strategy mitigates SCFs effectively and exhibits good performance in recovery.

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“…L INE commutated converter based high-voltage direct current (LCC-HVDC) transmission has been widely employed for long-distance bulk-power delivery and asynchronous interconnections [1], [2]. However, due to the utilization of the thyristors, commutation failure (CF) is rooted in LCC-HVDC given the adverse factors such as voltage fluctuation on the AC side of the inverter station [3]. It is hard to completely avoid the first CF (FCF) utilizing the control optimization based methods for the reason that the interval from the fault occurrence to the FCF only sustains a few milliseconds, which consequently leads to subsequent CF (SCF).…”

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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Commutation Failure Mitigation Method Based on Imaginary Commutation Process

Cited by 14 publications

References 14 publications

Suppression to concurrent commutation failure of UHVDC with hierarchical connection mode based on improved dc current prediction

Suppression to concurrent commutation failure of UHVDC with hierarchical connection mode based on improved dc current prediction

DC Current Order Optimization Based Strategy for Recovery Performance Improvement of LCC-HVDC Transmission Systems

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

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