Results 1 to 10 of about 1,303 (282)
An Improved Commutation Prediction Algorithm to Mitigate Commutation Failure in High Voltage Direct Current [PDF]
Energies, 2017 Commutation failure is a common fault for line-commutated converters in the inverter. To reduce the possibility of commutation failure, many prediction algorithms based on alternating current (AC) voltage detection have already been implemented in high voltage direct current (HVDC) control and protection systems.
Ziping Wu, Li Yanan
exaly +5 more sources
Procedure analysis of UHVDC commutation failure
The Journal of Engineering, 2018 There may be a commutation failure during a fault or start‐up of the UHVDC inverter side. The law of commutation failure process in UHVDC converter is studied here. First, the cause of inverter commutation failures is briefly introduced. Then, the general law for the bridge arm conduction of the inverter in the process of the commutation failure is ...
Chenqing Wang +4 more
doaj +4 more sources
Commutation Failure Mitigation Method Based on Imaginary Commutation Process
Journal of Modern Power Systems and Clean Energy, 2022 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.
Renlong Zhu +2 more
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Characteristics of commutation failure based on fault recording
The Journal of Engineering, 2019 Commutation failure of the high‐voltage direct current (HVDC) transmission system is common fault in a converter station. The fault recording in one converter station when commutation failure caused by the disturbance of the AC system was collected, and the turn‐off angle of valves, zero‐crossing offset, and landing amplitude of bus voltage were ...
Han Zheng +6 more
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Commutation Failure Prediction Method Considering Commutation Voltage Distortion and DC Current Variation [PDF]
IEEE Access, 2019 Commutation failure (CF) at the inverter side is one of the most common failures in the line-commutated converter-based high voltage direct current (LCC-HVDC) system. Effective prediction of CF helps to formulate and implement protection measures timely.
Chaoming Zhang
exaly +4 more sources
A detection method for HVDC commutation failure based on the variation rate of commutation inductance energy [PDF]
IET Generation, Transmission & Distribution, 2022 Abstract Concerning the insufficient accuracy of the criterion for identifying commutation failure in HVDC transmission systems, a new detection method for commutation failure based on the variation rate of commutation inductance energy is proposed.
Jing Ma, Chen Liu, Peng Cheng
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The failure of the uncountable non-commutative Specker Phenomenon [PDF]
Journal of Group Theory, 2001 Higman proved in 1952 that every free group is non-commutatively slender, this is to say that if G is a free group and h is a homomorphism from the countable complete free product (X_omega Z) to G, then there exists a finite subset F of omega and a homomorphism h:*_{i in F} Z --> G such that h=h rho_F, where rho_F is the natural map from (X_{i in ...
Shelah, Saharon, Strüngmann, Lutz
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A Commutation Failure Prediction and Mitigation Method
Journal of Modern Power Systems and Clean Energy, 2022 The mitigation of commutation failure (CF) depends on the accuracy of CF prediction. In terms of the large error of the existing extinction angle (EA) calculation during the fault transient period, a method for CF prediction and mitigation is proposed. Variations in both DC current and overlap angle (OA) are considered in the proposed method to predict
Renlong Zhu +4 more
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Mitigating commutation failures in HVDC systems with SFCL deployment
International Journal of Electrical Power & Energy Systems, 2023 Commutation failures represent a prevalent issue encountered in line-commutated-converter high voltage direct current (LCC-HVDC) systems. As the widespread deployment of HVDC systems continues, the risk associated with commutation failures increases, posing a growing threat to power grids due to their potential to trigger severe consequences, including
Qihuan Dong +5 more
openaire +4 more sources
Effect of commutation failure on the distance protection and the countermeasures
IET Generation, Transmission & Distribution, 2015 Commutation failure (CF) may be caused by AC fault in AC/DC interconnected system, and it will affect the performance of distance protection. The transient characteristic of equivalent current of power‐frequency of the dc–ac inverter is first analysed by introducing the concept of quadrant.
Shao‐feng Huang +3 more
openaire +1 more source