An Enhanced Current Differential Protection for AC Transmission Lines Connecting MMC-HVDC Stations

Liang, Yingyu; Ren, Yi; He, Weixuan

doi:10.1109/jsyst.2022.3155881

Cited by 8 publications

(7 citation statements)

References 32 publications

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“…This is attributed to the overcurrent capability of the fully controlled power electronic devices and the highly controllable characteristics of the converter station. Because of the above special fault characteristics, the traditional current differential protection algorithm may undergo performance degradation or even give incorrect operation in the presence of MMCbased converter stations [14]. In addition, some nonideal conditions during external faults, e.g., CT saturation and outliers, also negatively affect the security of the differential protection.…”

Section: Current Trajectory Image Formed By Dual Differential Currentsmentioning

confidence: 99%

“…3a. CT saturation can cause the measured differential current to (1) Frequency-Domain based scheme [7][8][9]14] The fault behaviors of MMC are considered. Thus, they can operate well in the presence of MMC-HVDC stations Inherent demerits of frequency-domain based scheme include the requirement of discrete Fourier transform, the negative effect of decaying DC component on accuracy of phasor estimation Some of them have no natural phase selection capability [7][8][9] Time-Domain based scheme [10][11][12][13]15] Discrete Fourier transform is removed.…”

Section: Analysis Of Differential Current Waveformsmentioning

confidence: 99%

“…12a. However, when an MMC-based converter station is present and operates in rectifier mode, it is possible that the phase difference of the fault currents between the two sides of the AC line is an obtuse angle [14]. In this case, operating current may be lower than restraining current, causing CDP to have high probability of being ineffective, as shown in Fig.…”

Section: Comparison Of Cdp and Proposed Protection Algorithmmentioning

confidence: 99%

“…Additionally, the schemes in [10][11][12][13] do not have good tolerance against some nonideal conditions during an external fault, e.g., CT saturation and outliers. Reference [14] proposes an enhanced current differential protection scheme that has good performance in different operational modes of the MMC. However, two additional methods are introduced to eliminate the negative effects of CT saturation and outliers, considerably increasing the complexity of the protection scheme.…”

Section: Introductionmentioning

confidence: 99%

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Current trajectory image-based protection algorithm for transmission lines connected to MMC-HVDC stations using CA-CNN

Liang

Ren

et al. 2023

Prot Control Mod Power Syst

Self Cite

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In the presence of an MMC-HVDC system, current differential protection (CDP) has the risk of failure in operation under an internal fault. In addition, CDP may also incur security issues in the presence of current transformer (CT) saturation and outliers. In this paper, a current trajectory image-based protection algorithm is proposed for AC lines connected to MMC-HVDC stations using a convolution neural network improved by a channel attention mechanism (CA-CNN). Taking the dual differential currents as two-dimensional coordinates of the moving point, the moving-point trajectories formed by differential currents have significant differences under internal and external faults. Therefore, internal faults can be identified using image recognition based on CA-CNN. This is improved by a channel attention mechanism, data augmentation, and adaptive learning rate. In comparison with other machine learning algorithms, the feature extraction ability and accuracy of CA-CNN are greatly improved. Various fault conditions like different network structures, operation modes, fault resistances, outliers, and current transformer saturation, are fully considered to verify the superiority of the proposed protection algorithm. The results confirm that the proposed current trajectory image-based protection algorithm has strong learning and generalizability, and can identify internal faults reliably.

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Section: Current Trajectory Image Formed By Dual Differential Currentsmentioning

confidence: 99%

Section: Analysis Of Differential Current Waveformsmentioning

confidence: 99%

Section: Comparison Of Cdp and Proposed Protection Algorithmmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Current trajectory image-based protection algorithm for transmission lines connected to MMC-HVDC stations using CA-CNN

Liang

Ren

et al. 2023

Prot Control Mod Power Syst

Self Cite

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show abstract

“…The non-unified and limited fault currents from CBRs can pose severe challenges to the reliable operation of existing AC protection devices. For example, as reported in [3] - [5], the connection of CBRs can lead to a range of protection system issues, such as the failed detection and/or coordination of overcurrent protection, the under/over-reach and phase selection of distance protection, and the failed operation of the differential protection during internal faults.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of travelling wave protection performance in converter-dominated networks

Liu,

Hong,

Dyśko

et al. 2024

17th International Conference on Developments in Power System Protection (DPSP 2024)

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This paper presents a comprehensive study to investigate the travelling wave protection performance in networks with high penetration of Converter-Based Resources (CBRs). Representative network models are developed in the sub-step environment of the Real-Time Digital Simulator (RTDS) and realistic Hardware-in-the-Loop (HiL) tests are conducted on a pair of travelling wave relays (TWRs) to emulate realistic system and fault scenarios. The studies have been conducted in two stages: firstly, systematic tests with a total number of 300 cases have been conducted to have a high-level assessment of TWRs' performance under different fault conditions, e.g. varied fault types, fault positions, Fault Inception Angles (FIAs), and fault resistances; and secondly, detailed investigation has been conducted on selected and representative cases to understand the impact of various factors, e.g. the line-end transformer, system fault levels, converter controls and external faults, on the protection performance. Based on the test results and analysis, it was found that the performance of the TWR is largely unaffected by the variation of system fault levels and converter control strategies, but the connection of the line-end transformer and the low FIAs present challenges for the healthy operation of TWRs in some conditions. Although the tests were conducted for a pair of specific commercially available TWRs, the results have been analysed in a generic manner, so the findings will not only facilitate understanding the benefits/limitations of travelling wave protection in the network with high amounts of CBRs, but also provide a valuable reference for system operators to select the protection solutions in the future.

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Adaptive additional current-based line differential protection in the presence of converter- interfaced sources with four quadrant operation capability

Liang¹,

Ren²,

Fan³

et al. 2023

International Journal of Electrical Power & Energy Systems

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An Enhanced Current Differential Protection for AC Transmission Lines Connecting MMC-HVDC Stations

Cited by 8 publications

References 32 publications

Current trajectory image-based protection algorithm for transmission lines connected to MMC-HVDC stations using CA-CNN

Current trajectory image-based protection algorithm for transmission lines connected to MMC-HVDC stations using CA-CNN

Evaluation of travelling wave protection performance in converter-dominated networks

Adaptive additional current-based line differential protection in the presence of converter- interfaced sources with four quadrant operation capability

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