A Predictive Method of LCC-HVDC Continuous Commutation Failure Based on Threshold Commutation Voltage Under Grid Fault

Ouyang, Jinxin; Zhang, Zhen; Li, Mengyang; Pang, Mingyu; Xiong, Xiaofu; Diao, Yanbo

doi:10.1109/tpwrs.2020.3001939

Cited by 56 publications

(18 citation statements)

References 23 publications

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“…To have enough post-fault commutation margin, the actual A γ should be equal to the critical A γ,cr . Hence one gets (17), where the subscript f denotes the fault layer. The phase shift of the ac voltage after the asymmetric fault, that is, φ is derived from the 2 nd order generalized integrator (SOGI), the zerocrossing detector (ZCD), and the phase locked loop (PLL), as seen in Figure 7.…”

Section: Finding the Reference To The Extinction Angle With Constant ...mentioning

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: Finding the Reference To The Extinction Angle With Constant ...mentioning

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.…”

mentioning

confidence: 99%

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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“…where N p R cr and N p R ci are the equivalent resistance of the rectifier station and the inverter station, respectively. Equation ( 18) was derived based on Equations ( 16) and (17).…”

Section: Risk Assessment Of Scfsmentioning

confidence: 99%

“…The recovery performance of a CF was improved in order to prevent the occurrence of SCFs by modifying the lower and upper limits of a Constant Extinction Angle (CEA) controller in [16]. Based on an analysis of the controller response and AC/DC interaction, an early warning system for SCFs was developed by considering the risks of controller regulation and the variations in electrical quantities in [17,18], and an emergency advanced control strategy was proposed with an adjustment of the inverter beta in [17]. In addition, the impact of the conventional Phase-Locked Loop (PLL) on SCFs during an AC fault was analyzed.…”

Section: Introductionmentioning

confidence: 99%

Mechanism Analysis of a Subsequent Commutation Failure and a DC Power Recovery Speed Control Strategy

Zheng

Wang

et al. 2022

Electronics

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A subsequent commutation failure (SCF) of the Line-Commutated Converter–High-Voltage Direct Current (LCC-HVDC) may occur during the recovery after the clearance of an AC fault, seriously threatening the safe and stable operation of the LCC-HVDC and the entire post-fault AC/DC hybrid power system. In this study, the mechanism of an SCF as affected by the transient stability was analyzed, and a DC power recovery speed control strategy is proposed as an additional form of control to prevent the occurrence of SCFs. First, the sending-end and receiving-end power systems were modeled as synchronous generators instead of ideal voltage sources, and the mechanism of an SCF as affected by the transient stability was analyzed and verified. Second, the ramp function was adopted to describe the recovery characteristic of DC power, and a model of its recovery was established. Then, the recovery speed control strategy is presented based on the mechanism analysis of SCFs, which can not only be used to avoid the occurrence of SCFs but also increase the transient stability margin of the sending-end power system. Finally, the effectiveness and robustness of the proposed control strategy were validated by using a hybrid electromechanical–electromagnetic model and the full electromagnetic model of the IEEE 39-bus asynchronous interconnection test power system. With the implementation of the proposed control strategy, the safe and stable operation of the LCC-HVDC and AC/DC hybrid power system can be guaranteed. The adaptive DC power recovery speed control strategy will be further investigated in future research work.

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“…It is impossible to pray that such a given value can be universally applicable for all transient processes. On the other hand, the extinction angle is defined as the electric angle between the current zero-crossing point and the positive zero-crossing point of the commutation voltage of each converter valve [11], [12]. Therefore, an accurate measured extinction angle is highly dependent on the zero-crossing point of voltage or current.…”

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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A Predictive Method of LCC-HVDC Continuous Commutation Failure Based on Threshold Commutation Voltage Under Grid Fault

Cited by 56 publications

References 23 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

Mechanism Analysis of a Subsequent Commutation Failure and a DC Power Recovery Speed Control Strategy

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

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