Subjects -> ENGINEERING (Total: 2688 journals)
    - CHEMICAL ENGINEERING (229 journals)
    - CIVIL ENGINEERING (237 journals)
    - ELECTRICAL ENGINEERING (176 journals)
    - ENGINEERING (1325 journals)
    - ENGINEERING MECHANICS AND MATERIALS (452 journals)
    - HYDRAULIC ENGINEERING (56 journals)
    - INDUSTRIAL ENGINEERING (98 journals)
    - MECHANICAL ENGINEERING (115 journals)

ENGINEERING (1325 journals)                  1 2 3 4 5 6 7 | Last

Showing 1 - 200 of 1205 Journals sorted by number of followers
Composite Structures     Hybrid Journal   (Followers: 247)
Composites Part B : Engineering     Hybrid Journal   (Followers: 221)
IEEE Spectrum     Full-text available via subscription   (Followers: 219)
ACS Nano     Hybrid Journal   (Followers: 183)
Composites Part A : Applied Science and Manufacturing     Hybrid Journal   (Followers: 175)
IEEE Geoscience and Remote Sensing Letters     Hybrid Journal   (Followers: 151)
Composites Science and Technology     Hybrid Journal   (Followers: 150)
IEEE Instrumentation & Measurement Magazine     Hybrid Journal   (Followers: 148)
IEEE Communications Magazine     Full-text available via subscription   (Followers: 140)
IEEE Engineering Management Review     Full-text available via subscription   (Followers: 117)
IEEE Antennas and Propagation Magazine     Hybrid Journal   (Followers: 112)
IEEE Transactions on Control Systems Technology     Hybrid Journal   (Followers: 111)
IEEE Transactions on Instrumentation and Measurement     Hybrid Journal   (Followers: 106)
IEEE Transactions on Signal Processing     Hybrid Journal   (Followers: 92)
IEEE Antennas and Wireless Propagation Letters     Hybrid Journal   (Followers: 88)
IEEE Industry Applications Magazine     Full-text available via subscription   (Followers: 82)
IEEE Transactions on Antennas and Propagation     Full-text available via subscription   (Followers: 79)
IEEE Transactions on Engineering Management     Hybrid Journal   (Followers: 74)
Engineering Failure Analysis     Hybrid Journal   (Followers: 68)
IEEE Microwave Magazine     Full-text available via subscription   (Followers: 63)
IEEE Signal Processing Letters     Hybrid Journal   (Followers: 60)
IEEE Transactions on Reliability     Hybrid Journal   (Followers: 53)
Experimental Techniques     Hybrid Journal   (Followers: 51)
IET Radar, Sonar & Navigation     Open Access   (Followers: 50)
IEEE Transactions on Microwave Theory and Techniques     Hybrid Journal   (Followers: 49)
Control Engineering Practice     Hybrid Journal   (Followers: 46)
IEEE Journal of Selected Topics in Signal Processing     Hybrid Journal   (Followers: 43)
Biotechnology Progress     Hybrid Journal   (Followers: 42)
IEEE Potentials     Full-text available via subscription   (Followers: 42)
IEEE Journal on Selected Areas in Communications     Hybrid Journal   (Followers: 39)
Heat Transfer Engineering     Hybrid Journal   (Followers: 36)
IET Microwaves, Antennas & Propagation     Open Access   (Followers: 35)
International Journal for Numerical Methods in Engineering     Hybrid Journal   (Followers: 35)
IEEE Microwave and Wireless Components Letters     Hybrid Journal   (Followers: 35)
Digital Signal Processing     Hybrid Journal   (Followers: 34)
IEEE Transactions on Knowledge and Data Engineering     Hybrid Journal   (Followers: 32)
AIChE Journal     Hybrid Journal   (Followers: 31)
Computing in Science & Engineering     Full-text available via subscription   (Followers: 31)
Computers & Geosciences     Hybrid Journal   (Followers: 30)
Flow, Turbulence and Combustion     Hybrid Journal   (Followers: 30)
Coastal Management     Hybrid Journal   (Followers: 29)
Canadian Geotechnical Journal     Hybrid Journal   (Followers: 28)
GPS Solutions     Hybrid Journal   (Followers: 28)
Fluid Dynamics     Hybrid Journal   (Followers: 27)
Bell Labs Technical Journal     Hybrid Journal   (Followers: 27)
Géotechnique     Hybrid Journal   (Followers: 27)
IEEE Transactions on Information Theory     Hybrid Journal   (Followers: 27)
IEEE Transactions on Power Delivery     Hybrid Journal   (Followers: 26)
Applied Energy     Partially Free   (Followers: 26)
Advances in Engineering Software     Hybrid Journal   (Followers: 26)
IEEE Journal of Solid-State Circuits     Full-text available via subscription   (Followers: 24)
Corrosion Science     Hybrid Journal   (Followers: 23)
Engineering & Technology     Hybrid Journal   (Followers: 22)
IET Image Processing     Open Access   (Followers: 22)
Intermetallics     Hybrid Journal   (Followers: 21)
Combustion, Explosion, and Shock Waves     Hybrid Journal   (Followers: 21)
IEEE Transactions on Electronics Packaging Manufacturing     Hybrid Journal   (Followers: 21)
IET Signal Processing     Open Access   (Followers: 21)
IEEE Transactions on Circuits and Systems II: Express Briefs     Hybrid Journal   (Followers: 20)
Advanced Synthesis & Catalysis     Hybrid Journal   (Followers: 20)
Implementation Science     Open Access   (Followers: 20)
International Journal for Numerical Methods in Fluids     Hybrid Journal   (Followers: 19)
Engineering Optimization     Hybrid Journal   (Followers: 19)
International Communications in Heat and Mass Transfer     Hybrid Journal   (Followers: 19)
Electrophoresis     Hybrid Journal   (Followers: 18)
IET Circuits, Devices & Systems     Open Access   (Followers: 18)
IEEE/ACM Transactions on Computational Biology and Bioinformatics     Hybrid Journal   (Followers: 18)
International Journal of Adhesion and Adhesives     Hybrid Journal   (Followers: 18)
IEEE Transactions on Intelligent Transportation Systems     Hybrid Journal   (Followers: 17)
Experiments in Fluids     Hybrid Journal   (Followers: 17)
Computational Geosciences     Hybrid Journal   (Followers: 17)
Integration     Hybrid Journal   (Followers: 16)
IEEE Transactions on Energy Conversion     Hybrid Journal   (Followers: 16)
Engineering Geology     Hybrid Journal   (Followers: 16)
European Journal of Mass Spectrometry     Hybrid Journal   (Followers: 16)
Energy Conversion and Management     Hybrid Journal   (Followers: 15)
Bulletin of Engineering Geology and the Environment     Hybrid Journal   (Followers: 15)
Coastal Engineering     Hybrid Journal   (Followers: 15)
IEEE Transactions on Magnetics     Hybrid Journal   (Followers: 14)
IEEE Journal of Biomedical and Health Informatics     Hybrid Journal   (Followers: 14)
IEEE Transactions on Automation Science and Engineering     Full-text available via subscription   (Followers: 13)
IEEE Transactions on Evolutionary Computation     Hybrid Journal   (Followers: 13)
Electromagnetics     Hybrid Journal   (Followers: 13)
Computers and Geotechnics     Hybrid Journal   (Followers: 12)
IEEE Transactions on Semiconductor Manufacturing     Hybrid Journal   (Followers: 12)
IET Renewable Power Generation     Open Access   (Followers: 12)
Human Factors in Ergonomics & Manufacturing     Hybrid Journal   (Followers: 12)
IEEE Transactions on Professional Communication     Hybrid Journal   (Followers: 11)
Biomedical Engineering     Hybrid Journal   (Followers: 11)
IEEE Transactions on Education     Hybrid Journal   (Followers: 11)
CIRP Annals - Manufacturing Technology     Hybrid Journal   (Followers: 11)
Heat Transfer - Asian Research     Hybrid Journal   (Followers: 11)
IEEE Journal of Oceanic Engineering     Hybrid Journal   (Followers: 11)
International Journal of Antennas and Propagation     Open Access   (Followers: 10)
Proceedings of the Institution of Civil Engineers - Geotechnical Engineering     Hybrid Journal   (Followers: 10)
IEEE Transactions on Nuclear Science     Hybrid Journal   (Followers: 10)
IEEE Transactions on Plasma Science     Hybrid Journal   (Followers: 10)
Computers & Mathematics with Applications     Full-text available via subscription   (Followers: 9)
Fuel Cells Bulletin     Full-text available via subscription   (Followers: 9)
Computational Optimization and Applications     Hybrid Journal   (Followers: 9)
Annals of Science     Hybrid Journal   (Followers: 9)
European Journal of Engineering Education     Hybrid Journal   (Followers: 9)
Applied Catalysis B: Environmental     Hybrid Journal   (Followers: 9)
Biomedical Microdevices     Hybrid Journal   (Followers: 8)
IEEE Technology and Society Magazine     Full-text available via subscription   (Followers: 8)
Fuel Cells     Hybrid Journal   (Followers: 8)
Adaptive Behavior     Hybrid Journal   (Followers: 8)
Proceedings of the Institution of Civil Engineers - Bridge Engineering     Hybrid Journal   (Followers: 8)
Energy Engineering     Full-text available via subscription   (Followers: 8)
IEEE Transactions on Advanced Packaging     Full-text available via subscription   (Followers: 8)
Clay Minerals     Hybrid Journal   (Followers: 8)
Continuum Mechanics and Thermodynamics     Hybrid Journal   (Followers: 8)
Applied Catalysis A: General     Hybrid Journal   (Followers: 7)
International Journal of Applied Ceramic Technology     Hybrid Journal   (Followers: 7)
Basin Research     Hybrid Journal   (Followers: 7)
Discrete Optimization     Full-text available via subscription   (Followers: 7)
Designs, Codes and Cryptography     Hybrid Journal   (Followers: 7)
IEEE Journal of Selected Topics in Quantum Electronics     Hybrid Journal   (Followers: 7)
Environmental and Ecological Statistics     Hybrid Journal   (Followers: 7)
Biomicrofluidics     Open Access   (Followers: 7)
Geothermics     Hybrid Journal   (Followers: 7)
Fuel and Energy Abstracts     Full-text available via subscription   (Followers: 7)
IEEE Vehicular Technology Magazine     Full-text available via subscription   (Followers: 7)
Catalysis Communications     Hybrid Journal   (Followers: 7)
Computers and Electronics in Agriculture     Hybrid Journal   (Followers: 7)
Computer Applications in Engineering Education     Hybrid Journal   (Followers: 6)
Computing and Visualization in Science     Hybrid Journal   (Followers: 6)
Fusion Engineering and Design     Hybrid Journal   (Followers: 6)
Applied Clay Science     Hybrid Journal   (Followers: 6)
Composite Interfaces     Hybrid Journal   (Followers: 6)
Formal Methods in System Design     Hybrid Journal   (Followers: 6)
Acta Geotechnica     Hybrid Journal   (Followers: 6)
Advances in OptoElectronics     Open Access   (Followers: 6)
International Journal of Adaptive Control and Signal Processing     Hybrid Journal   (Followers: 5)
IEEE Transactions on Vehicular Technology     Hybrid Journal   (Followers: 5)
IET Science, Measurement & Technology     Open Access   (Followers: 5)
IEEE Transactions on Applied Superconductivity     Hybrid Journal   (Followers: 5)
International Journal of Architectural Computing     Full-text available via subscription   (Followers: 5)
Finite Fields and Their Applications     Full-text available via subscription   (Followers: 5)
Focus on Powder Coatings     Full-text available via subscription   (Followers: 5)
Engineering With Computers     Hybrid Journal   (Followers: 5)
Proceedings of the Institution of Civil Engineers - Engineering Sustainability     Hybrid Journal   (Followers: 5)
Archives of Computational Methods in Engineering     Hybrid Journal   (Followers: 5)
Active and Passive Electronic Components     Open Access   (Followers: 5)
Proceedings of the Institution of Civil Engineers - Ground Improvement     Hybrid Journal   (Followers: 4)
Frontiers in Energy     Hybrid Journal   (Followers: 4)
Adsorption     Hybrid Journal   (Followers: 4)
Catalysis Today     Hybrid Journal   (Followers: 4)
Applied Numerical Mathematics     Hybrid Journal   (Followers: 4)
Current Applied Physics     Full-text available via subscription   (Followers: 4)
Fluid Phase Equilibria     Hybrid Journal   (Followers: 4)
Graphs and Combinatorics     Hybrid Journal   (Followers: 4)
Filtration & Separation     Full-text available via subscription   (Followers: 4)
Annals of Pure and Applied Logic     Open Access   (Followers: 4)
Grass and Forage Science     Hybrid Journal   (Followers: 4)
Catalysis Surveys from Asia     Hybrid Journal   (Followers: 4)
Informatik-Spektrum     Hybrid Journal   (Followers: 3)
Engineering Computations     Hybrid Journal   (Followers: 3)
European Journal of Combinatorics     Full-text available via subscription   (Followers: 3)
Applicable Algebra in Engineering, Communication and Computing     Hybrid Journal   (Followers: 3)
Chaos : An Interdisciplinary Journal of Nonlinear Science     Hybrid Journal   (Followers: 3)
Concurrent Engineering     Hybrid Journal   (Followers: 3)
Focus on Pigments     Full-text available via subscription   (Followers: 3)
Annals of Combinatorics     Hybrid Journal   (Followers: 3)
Frontiers of Environmental Science & Engineering     Hybrid Journal   (Followers: 3)
Fuzzy Sets and Systems     Hybrid Journal   (Followers: 3)
Catalysis Letters     Hybrid Journal   (Followers: 3)
IET Generation, Transmission & Distribution     Open Access   (Followers: 2)
Historical Records of Australian Science     Hybrid Journal   (Followers: 2)
IET Optoelectronics     Open Access   (Followers: 2)
Assembly Automation     Hybrid Journal   (Followers: 2)
International Journal of Abrasive Technology     Hybrid Journal   (Followers: 2)
Aerobiologia     Hybrid Journal   (Followers: 2)
Cellular and Molecular Neurobiology     Hybrid Journal   (Followers: 2)
Comptes Rendus : Mécanique     Open Access   (Followers: 2)
Chinese Journal of Catalysis     Full-text available via subscription   (Followers: 2)
IEEE Latin America Transactions     Full-text available via subscription   (Followers: 2)
Communications in Numerical Methods in Engineering     Hybrid Journal   (Followers: 2)
ESAIM: Control Optimisation and Calculus of Variations     Open Access   (Followers: 2)
Focus on Surfactants     Full-text available via subscription   (Followers: 2)
Engineering Analysis with Boundary Elements     Hybrid Journal   (Followers: 2)
Chaos, Solitons & Fractals     Hybrid Journal   (Followers: 1)
Foundations of Science     Hybrid Journal   (Followers: 1)
Forschung     Hybrid Journal   (Followers: 1)
European Journal of Lipid Science and Technology     Hybrid Journal   (Followers: 1)
Antarctic Science     Hybrid Journal   (Followers: 1)
Épités - Épitészettudomány     Full-text available via subscription   (Followers: 1)
Dyes and Pigments     Hybrid Journal   (Followers: 1)
Bautechnik     Hybrid Journal   (Followers: 1)
Biointerphases     Open Access   (Followers: 1)
Designed Monomers and Polymers     Open Access   (Followers: 1)
Color Research & Application     Hybrid Journal   (Followers: 1)
Abstract and Applied Analysis     Open Access   (Followers: 1)
Focus on Catalysts     Full-text available via subscription  
ESAIM: Proceedings     Open Access  
Environmetrics     Hybrid Journal  
COMBINATORICA     Hybrid Journal  
Chinese Science Bulletin     Open Access  
Calphad     Hybrid Journal  
Boundary Value Problems     Open Access  

        1 2 3 4 5 6 7 | Last

Similar Journals
Journal Cover
IEEE Transactions on Power Delivery
Journal Prestige (SJR): 1.814
Citation Impact (citeScore): 5
Number of Followers: 26  
 
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
ISSN (Print) 0885-8977
Published by IEEE Homepage  [228 journals]
  • IEEE Power & Energy Society

    • Free pre-print version: Loading...

      Abstract: Presents a listing of the editorial board, board of governors, current staff, committee members, and/or society editors for this issue of the publication.
      PubDate: April 2022
      Issue No: Vol. 37, No. 2 (2022)
       
  • Information for Authors

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      Abstract: These instructions give guidelines for preparing papers for this publication. Presents information for authors publishing in this journal.
      PubDate: April 2022
      Issue No: Vol. 37, No. 2 (2022)
       
  • Blank page

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      Abstract: This page or pages intentionally left blank.
      PubDate: April 2022
      Issue No: Vol. 37, No. 2 (2022)
       
  • 2021 List of Outstanding Reviewers

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      Pages: 695 - 695
      Abstract: Presents a listing a reviewers who contributed to this publication in 2021.
      PubDate: April 2022
      Issue No: Vol. 37, No. 2 (2022)
       
  • Pilot Directional Protection Scheme for LCC-HVDC Transmission Lines Based
           on the Voltage difference Between Positive and Negative Poles

    • Free pre-print version: Loading...

      Authors: Jing Ma;Yuchong Wu;Chen Liu;A. G. Phadke;Peng Cheng;
      Pages: 696 - 709
      Abstract: Currently available DC line protection methods for AC/DC hybrid systems present poor immunity to fault resistance for in-zone faults and mal-operation problems for out-of-zone faults. This paper proposes a new pilot directional protection scheme based on the voltage difference between positive and negative poles (VDPN). The proposed method is not affected by the fault location, the fault resistance, or lightning interference. By analyzing the conducting states of the converter in different time intervals, the differential expressions of the injected current from AC system to DC system are derived. Calculation models of VDPN in different conducting states are built. Then, according to the consistency between the calculated value and actual value of voltage difference, the protection criterion for DC line fault is constructed. Finally, simulation tests in RT-LAB verify that the proposed scheme can correctly identify in-zone and out-of-zone faults in different fault cases. Besides, the proposed scheme has low demand on data synchronicity, thus it is simple and reliable with a good operation speed.
      PubDate: April 2022
      Issue No: Vol. 37, No. 2 (2022)
       
  • Melting Pattern of Vacuum Interrupter Contacts Subjected to High Inrush
           Currents at High Frequencies

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      Authors: Roy Alexander;Edgar Dullni;
      Pages: 710 - 715
      Abstract: One important aspect in capacitor switching concerns the high inrush current during the energizing of the capacitor. For vacuum interrupters, it is assumed that the modification of the contact surface due to high inrush currents has the highest impact on the current breaking performance. One peculiarity of capacitor switching is the high rate of switching operations easily achieving 1000 operations in a couple of years. Two vacuum breakers were therefore operated up to 1000 times in a simple test circuit simulating the making of high inrush currents. According to standards, peak and frequency of inrush currents are 20 kA and 4250 Hz for back-to-back capacitor switching, or around 5 kA and 400 Hz for single bank switching. The range of inrush currents was extended here to peak currents up to 60 kA and frequencies up to 24 kHz. Peak current and frequency have an important impact on radius and current density of the inrush current arc, and thus on the energy deposited under the arc roots. Under the conditions prevailing here, the whole surface of the contacts exhibits a uniform melting pattern with the depth of the solidified melt being less than 1 mm after 1000 operations. It is assumed that the arc moves on the contact surface driven by the radial magnetic forces generated by this kind of contact and distributes the arc energy all over the contact surface. The inrush current integral (ICI) might be a measure of the available energy for contact melting or erosion. However, since the ICI has no relation to the arc current density, it is only representative for a particular melting pattern of the contact surface if frequency and peak inrush currents are varied in a limited range.
      PubDate: April 2022
      Issue No: Vol. 37, No. 2 (2022)
       
  • Complete Provision of MPC-Based LFC By Electric Vehicles With Inertial and
           Droop Support from DFIG-Based Wind Farm

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      Authors: Musa Khan;Haishun Sun;
      Pages: 716 - 726
      Abstract: This paper taps on the participation ability of the Electric Vehicles Aggregator (EVA) in Load Frequency Control (LFC). The focus here is on EVA complete provision of LFC using Vehicle-to-Grid technology. This provision is possible however it faces two main challenges. The first one is the post-disturbance oscillations in the frequency when there is a time delay in the system. To cope with these oscillations two approaches are suggested. One is the application of constraints in the designing of model predictive control for LFC. Whereas the other is the emulated inertial and droop support from doubly-fed induction generator-based wind farm. This support along with the oscillation damping improved the overall frequency response to a disturbance. The second challenge is the variation in the sources’ especially of the EVAs’ capacity used for LFC. Acquiring the dynamic participation factor for these sources, successfully accommodated the variation in their capacities. Finally, this novel idea is tested through various case studies in Matlab/Simulink, including single and multiple LFC events, in the isolated and three-area systems. Hence establishing the EVs and DFIG-WFs’ potential of participating in grid frequency control by replacing partly or fully the fossil fuel-based sources.
      PubDate: April 2022
      Issue No: Vol. 37, No. 2 (2022)
       
  • A New Approach on Modeling of Pulsed-Power Loads

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      Authors: Amirehsan Rajabi-Nezhad;Ali Asghar Razi-Kazemi;
      Pages: 727 - 735
      Abstract: Pulsed power sources provide high-power waves with high frequency (HF) content for a wide range of applications. Conventionally, a simple resistance is employed for the most prevalent pulsed power loads. However, the load model can highly affect the efficiency of source design. This paper contributes to fill this gap by considering the HF behavior of the loads. Accordingly, a new approach has been proposed to present a general HF lumped-circuit model for pulsed power loads. The frequency response of the loads is identified using the Finite Integration Technique (FIT). Subsequently, an equivalent circuit model is established based on the vector fitting (VF) algorithm. The applicability of the approach has been verified by comparison with two experiments, i.e., Vircator and coaxial reactor as the loads. It is indicated that the HF-based model can significantly improve the simulation results to be in good agreement with experiments. The results present that while a pure-resistive load model could lead to about 30% error in the estimation of the characteristics of output voltage, it is about less than 5% in the case of the proposed HF load model.
      PubDate: April 2022
      Issue No: Vol. 37, No. 2 (2022)
       
  • Analysis of the Three-dimensional Temperature Distribution of Forced
           Cooled Power Cables

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      Authors: Heinrich Brakelmann;George J. Anders;
      Pages: 736 - 744
      Abstract: This paper introduces a new mathematical procedure for the calculation of power cable ampacities in the case of water-cooled circuits. Both, internal and external cooling installations are considered. The algorithm permits a non-iterative calculation of the water temperature and the temperature-dependent losses along the cooling length of the cables, evaluation of the heat absorbed and emitted by the cooling pipes as well as the effect of the water flow on the cable conductor temperature. Numerical examples show the effect of the direct and the indirect cooling on the ampacity of a 230 kV XLPE cable circuit.
      PubDate: April 2022
      Issue No: Vol. 37, No. 2 (2022)
       
  • Modelling on Novel Cable Traction Power Supply System and Power
           Distribution Analysis

    • Free pre-print version: Loading...

      Authors: Liyan Zhang;Shiwen Liang;Xin Li;Ying Jia;
      Pages: 745 - 754
      Abstract: Novel cable traction power supply system (NCTPSS) is a kind of long distance co-phase traction power supply system (TPSS), it can effectively solve problems caused by train's passing through electrical phase separation and improve utilization rate of regenerative energy in system, which is an ideal traction power supply mode. However, its structure is relatively complex due to cable power supply pattern, and internal power distribution mechanism still needs further study. In order to establish train-network coupling power flow calculation model, in this paper, two-port network model of each system component is established at first, then equivalent solid circuit model of the system is built by external cascade strategy and tearing nodal method. Then, power distribution, the changes of traction transformer power output and network voltage are analyzed under the condition that trains work in traction and regenerative braking condition, based on actual train operation schedule. The research shows that the proposed model can accurately calculate and detailed reflect electrical characteristics of NCTPSS, traction transformer capacity is effectively decreased compared with that needed in existing TPSS, regenerative power can feed back to entire cable traction network and be reused by traction trains with high utilization rate inside NCTPSS.
      PubDate: April 2022
      Issue No: Vol. 37, No. 2 (2022)
       
  • Adaptive Damping – An Improved Resonance Mitigation Scheme for
           Shunt Capacitors

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      Authors: Shuangting Xu;Yang Wang;Xianyong Xiao;Wilsun Xu;Yunfei Wang;
      Pages: 755 - 764
      Abstract: Adding a damping unit to a shunt capacitor is an effective way to mitigate capacitor-caused resonance. However, damping units suffer from power loss issues. This shortcoming is amplified further in cases where resonance has a low possibility of occurring. In view of this, an adaptive damping method is proposed to improve the existing scheme. The damping unit is capable of mitigating resonance and eliminating the power loss under the non-resonance condition. The core idea of the proposed approach is to add a breaker so that the damping unit can be switched on or off depending on whether resonance occurs. The design of and control mechanism for the proposed switchable damping unit are presented. The performances of the new resonance mitigation scheme in terms of harmonic mitigation, loading, switching transient and cost are verified for an actual capacitor application case.
      PubDate: April 2022
      Issue No: Vol. 37, No. 2 (2022)
       
  • Fast and Complete Mitigation of Residual Flux in Current Transformers
           Suitable for Auto-Reclosing Schemes Using Jiles-Atherton Modeling

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      Authors: Saeed Sanati;Yousef Alinejad-Beromi;
      Pages: 765 - 774
      Abstract: Accurate measurement of electrical currents cannot be done when the core of current transformers (CTs) is saturated. One of the reasons that causes saturation of a CT is the activation of the auto-reclose function for the circuit breaker. When the circuit breaker is switched off, a residual flux will remain in the CT core, and when the circuit breaker is reconnected, this residual flux may cause saturation of the CT core. It is necessary to remove the residual flux in an auto-reclosing scheme. In the auto-reclosing scheme, due to the short time interval between each reclosing shot of the circuit breaker, only methods that have a high-speed operation should be used to mitigate the residual flux to prevent CT core saturation. This paper introduces a fast and complete demagnetization method based on Jiles-Atherton magnetic modeling to mitigate the residual flux in the CT core. The advantages of this method are high-speed performance, independent of the CT characteristics, high accuracy and high reliability against the secondary open circuit. To evaluate the efficacy of the proposed method, software simulations and laboratory experiments are performed on a 63 kV, 300 A/5A CT. The results are presented and analyzed.
      PubDate: April 2022
      Issue No: Vol. 37, No. 2 (2022)
       
  • Multi-Objective Optimization of Distribution Networks via Daily
           Reconfiguration

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      Authors: Seyed-Mohammad Razavi;Hamid-Reza Momeni;Mahmoud-Reza Haghifam;Sadegh Bolouki;
      Pages: 775 - 785
      Abstract: This paper presents a comprehensive approach to improve the daily performance of an active distribution network (ADN), which includes renewable resources and responsive loads (RLs), using distribution network reconfiguration (DNR). The optimization objectives considered in this work can be described as (i) reducing active losses, (ii) improving the voltage profile, (iii) improving the network reliability, and (iv) minimizing the operation costs. The proposed approach also accounts for the probability of renewable resource failure given the information collected from their initial state at the beginning of each day. Furthermore, solar radiation variations are estimated based on past historical data, and the impact of the performance of renewable resources such as photovoltaics (PVs) is determined hourly based on a Markov model. Since the number of reconfiguration scenarios is very large, stochastic DNR (SDNR) based on the probability distance method is employed to shrink the scenarios set, before a self-adaptive modified crow search algorithm (SAMCSA) is introduced to find an optimal scenario. Finally, the IEEE 33-bus radial distribution system and the 86-bus Taiwan Power Company (TPC) system are investigated as two case studies to verify the effectiveness of the proposed method.
      PubDate: April 2022
      Issue No: Vol. 37, No. 2 (2022)
       
  • $mathcal+{H}_{infty+}$ +Control+Design+for+MMC-Based+HVDC+Links&rft.title=IEEE+Transactions+on+Power+Delivery&rft.issn=0885-8977&rft.date=2022&rft.volume=37&rft.spage=786&rft.epage=797&rft.aulast=Gomis-Bellmunt;&rft.aufirst=Saman&rft.au=Saman+Dadjo+Tavakoli;Sajjad+Fekriasl;Eduardo+Prieto-Araujo;Jef+Beerten;Oriol+Gomis-Bellmunt;">Optimal $mathcal {H}_{infty }$ Control Design for MMC-Based HVDC Links

    • Free pre-print version: Loading...

      Authors: Saman Dadjo Tavakoli;Sajjad Fekriasl;Eduardo Prieto-Araujo;Jef Beerten;Oriol Gomis-Bellmunt;
      Pages: 786 - 797
      Abstract: The modular multilevel converter (MMC) has emerged as the preferred choice for voltage source converter (VSC)-based high voltage direct current (HVDC) systems due to its low losses, low harmonic distortion, modularity, and redundancy. These advantages come at the expense of a complex control system with the strong coupling among its control variables, which complicates the design procedure of both its individual control loops and the DC link controllers. In fact, the performance improvement of a control loop could lead to degraded performance of other loops. Hence, to deal with such a complex dynamic system, this article suggests adopting multivariable $mathcal {H}_{infty }$ optimal control techniques in order to ensure stability and optimized performance of a VSC-HVDC link. First, a full-order, centralized multi-input-multi-output (MIMO) controller is derived based on $mathcal {H}_{infty }$ optimisation and used as a benchmark for the system performance level. Then, a fixed-structure, decentralized MIMO controller is synthesized to make a compromise between the optimal performance and feasibility of practical implementation. Finally, simulations are conducted to evaluate and compare the performance and robustness degradation due to the migration from a high-order, centralized controller towards a low-order, decentralized controller.
      PubDate: April 2022
      Issue No: Vol. 37, No. 2 (2022)
       
  • Stability Analysis of a Grid-Tied Interlinking Converter System With the
           Hybrid AC/DC Admittance Model and Determinant-Based GNC

    • Free pre-print version: Loading...

      Authors: Haitao Zhang;Mahmoud Mehrabankhomartash;Maryam Saeedifard;Yongqing Meng;Xiuli Wang;Xifan Wang;
      Pages: 798 - 812
      Abstract: This paper is mainly focused on the stability-related issues of a grid-tied interlinking converter system. First, hybrid AC/DC admittance characteristics of an interlinking converter operating under unity and non-unity power factors are analyzed separately. Then, by using the hybrid AC/DC admittance and determinant-based General Nyquist Criterion (GNC), the stability assessment, instability root cause identification, and instability mitigation of a grid-tied interlinking converter system are studied. In addition, decoupled mitigation of the AC- and DC-side instabilities are discussed based on the hybrid AC/DC admittance characteristics. The study results show that when an interlinking converter operates under unity power factor, the stabilities of the AC and DC sides are decoupled and can be regulated independently. To be more specific, the DC-side stability is subjected to the $d$-axis admittance, DC admittance, and their coupling admittances while the AC-side stability is dominated by the $q$-axis admittance. According to the hybrid AC/DC admittance characteristics, this paper further reveals that the DC-side stability is determined by the $d$-axis controllers. In contrast, the AC-side stability is governed by the $q$-axis controllers and the phase-locked loop (PLL). Finally, the analysis presented in this paper is verified based on frequency- and time-domain simulations in the Matlab/Simulink environment.
      PubDate: April 2022
      Issue No: Vol. 37, No. 2 (2022)
       
  • Robust Local Inhibitor of Reverse Power Tap Changer Runaway Events in
           Reconfigurable and Active Distribution Networks

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      Authors: Daniel da Conceição Pinheiro;João Paulo Abreu Vieira;Valéria Monteiro de Souza;Vanderson Carvalho de Souza;Heitor Alves Barata;Marcelo Sousa Costa;Alexandre Orpheo Rico Garcia;
      Pages: 813 - 822
      Abstract: Reverse power tap changerrunaway has become a challenging voltage issue with the increasing integration of distributed generation (DG) to reconfigurable distribution networks having step voltage regulators (SVRs). Local measurement-based runaway online inhibitor is important for correct tap changer operation when reverse power flow emerges on SVRs. However, gross errors of measurements available in SVR control can be quite significant, which further complicate the issue. This paper proposes a robust inhibitor of reverse power tap changer runaway events in reconfigurable and active distribution networks using local measurements and modes of operation available in SVR controls.1 A recursive least squares (RLS) estimation is proposed to mitigate the effect of gross SVR load-side voltage measurement errors on identifying the SVR weak side used for triggering SVR control modes in reverse power flow scenarios. A threshold range to assist in the SVR weak side identification is determined through a sensibility analysis. Simulation results on a real reconfigurable and active distribution network with cascade SVRs validate the effectiveness and robustness of the proposed algorithm.
      PubDate: April 2022
      Issue No: Vol. 37, No. 2 (2022)
       
  • Backflashover Performance Evaluation of the Partially Grounded Scheme of
           Overhead Lines With Fully Composite Pylons

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      Authors: Hanchi Zhang;Qian Wang;Filipe Faria da Silva;Claus Leth Bak;Kai Yin;Henrik Skouboe;
      Pages: 823 - 832
      Abstract: A design of a fully composite pylon has been proposed for new-generation 400 kV transmission towers to save line corridors and to reduce visual impact. Correspondingly, a method of external down-leads is proposed to bring grounding potential to the shield wires, together with a plan that not all pylons are grounded called ‘partially grounded transmission lines’ (PGTLs). This paper investigates backflashover performance of a partial grounding scheme of overhead lines (OHLs) supported by composite pylons. The transient analysis was carried out in PSCAD based on Monte Carlo method. For OHLs with every pylon grounded, reducing footing resistance and soil resistivity can improve backflashover performance effectively, but for PGTLs, these two methods do not have obvious effect and increasing insulation distance has limited effect. When lightning strikes at PGTLs, overvoltage is mainly dependent on the distance to the nearest grounded pylon and a longer distance will cause overvoltage with larger amplitude and longer wave front duration. Therefore, backflashover rate also increases along with the distance to the nearest grounded pylon until reaching a value limited by the inceptive condition of flashover. A coefficient recommended by CIGRE TB 63 to estimate backflashover rate is discussed and modified when using in PGTLs.
      PubDate: April 2022
      Issue No: Vol. 37, No. 2 (2022)
       
  • A Computer Vision System for Monitoring Disconnect Switches in
           Distribution Substations

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      Authors: Bogdan Tomoyuki Nassu;Bruno Marchesi;Rafael Wagner;Victor Barpp Gomes;Vanderlei Zarnicinski;Lourival Lippmann;
      Pages: 833 - 841
      Abstract: Knowing the state of the disconnect switches in a power distribution substation is important, since incorrect operation may lead to problems such as accidents, outages, and damaged equipment. Although human errors when reporting switch positions are rare, they can have a large impact when they occur, making automatic monitoring an attractive proposition, especially in substations without permanent staff. In this paper, we describe a non-intrusive computer vision system for monitoring the state of disconnect switches in distribution substations. The system employs regular surveillance cameras, which can also be used for other purposes, leading to lower cost and simpler installation and maintenance compared to individual per-switch sensors. Several challenges were addressed: cluttered backgrounds, occlusions, variations in lighting, weather and switch aspect, and the fact that it is often not possible to maneuver the switches during installation. We addressed these challenges by combining data provided by a human operator during installation with multiple machine learning models, relying on techniques such as SVMs for classifying SIFT or HOG features, and deep learning. By combining multiple outputs, the system achieved a 99.7365% success rate in experiments performed at a real substation over several days.
      PubDate: April 2022
      Issue No: Vol. 37, No. 2 (2022)
       
  • Estimation of Metal Oxide Surge Arresters' Useful Life Based on Time
           Series Forecasts

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      Authors: Vandilson R. N. Barbosa;George R. S. Lira;Marianna B. B. Dias;Edson G. Costa;
      Pages: 842 - 850
      Abstract: Estimating equipment useful life has been a challenge over the years. In this work, a methodology based on the application of a combined time series forecast model composed of the adaptive neuro-fuzzy inference system (ANFIS) and support vector machine for regression (SVR) is proposed to be used in the determination of metal oxide surge arresters’ (MOSAs’) useful life. For this purpose, field measurements were performed in order to build a time series database composed of values of the leakage current third harmonic component, considering that this component is one of the indicators of the MOSAs’ degradation level most used in arresters’ monitoring. Subsequently, the forecasting models (ANFIS and SVR) were implemented. Then a combined model was proposed using the obtained results of those models. The performance of each implemented models was evaluated using three types of errors: MSE, MAE, and MAPE. After of the models’ evaluation, the useful life estimation of the MOSA was carried out using the proposed model. Considering the obtained results, the forecasts using the combined model were more accurate than those provided by the models based on ANFIS and SVR. Thus, the proposed model was used to estimate the MOSA's useful life.
      PubDate: April 2022
      Issue No: Vol. 37, No. 2 (2022)
       
  • New Insights Into Calculations of AC Interference at Fundamental and
           Harmonic Frequencies Taking Account of the Phase Relationships of the
           Currents

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      Authors: David Boteler;Charalambos A. Charalambous;Kenneth Lax;
      Pages: 851 - 859
      Abstract: Electromagnetic interference to pipelines and railways from AC sources has long been a cause for concern. Methods and standards have evolved to enable calculations of the voltages produced under different conditions. These take into account the AC frequency, the soil resistivity and the pipeline characteristics. However, the approximations presented in some standards fail to take into account the phase relationship of the currents in the AC conductors and how that affects the induced currents in the earth. This paper re-examines these issues by introducing a revised complex image method for 3-phase systems that provides a simple and accurate way to include the influence of induced currents in calculations of the induced emf in nearby conductors. Normal positive sequence 3-phase currents produce fields in neighbouring conductors that tend to cancel. For the associated image currents in the earth, the cancellation is so complete that they have no influence on the induced emf. A different situation occurs with the zero sequence currents that occur during fault conditions and triplen harmonics. These currents are in phase, so there is none of the cancelling effect and the contributions from each conductor add to give a larger induced emf in a neighbouring conductor.
      PubDate: April 2022
      Issue No: Vol. 37, No. 2 (2022)
       
  • A Phasor Estimation Algorithm Robust to Decaying DC Component

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      Authors: Haotian Yu;Zongshuai Jin;Hengxu Zhang;Vladimir Terzija;
      Pages: 860 - 870
      Abstract: Phasor measurement is widely used in fault detection and localization of power systems. To improve the phasor measurement accuracy when the fault signal contains the decaying dc component (DDC), this article proposes a half-cycle DFT (HCDFT)-based phasor estimation algorithm. The error caused by DDC is estimated and removed from the phasor estimate by combining multiple HCDFT results that are computed using both the conventional basis vector and its corresponding complex conjugate. Both the numerical tests and the IEEE 39-bus system simulation tests are implemented to evaluate the performance of the proposed algorithm in comparison with four related phasor estimation algorithms. Test results show that the proposed algorithm can achieve accurate phasor estimation in the presence of DDC of a wide range of time constants under the interference of harmonics and noise. Moreover, the proposed algorithm is computationally efficient and its performance is independent of sampling rate. These merits make the proposed algorithm suitable to be applied in measurement and protection devices in real power systems.
      PubDate: April 2022
      Issue No: Vol. 37, No. 2 (2022)
       
  • Simulation Analysis of Critical Parameters for Thermal Stability of Surge
           Arresters

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      Authors: Yvonne Späck-Leigsnering;Maren Greta Ruppert;Erion Gjonaj;Herbert De Gersem;Volker Hinrichsen;
      Pages: 871 - 879
      Abstract: Ensuring thermal stability is an important aspect of an arrester design process. In this paper, the thermal stability of station class surge arresters is investigated using a coupled electrothermal numerical model. An ungraded 550-kV-station class arrester model is successfully validated against temperature measurements in power grid operation. The arrester cooling rate is introduced to determine the thermal stability threshold. Thermally stable and unstable scenarios are compared. The influence of selected arrester design parameters on the stability threshold is analyzed. It is shown that an improved heat transfer in the arrester air gap increases the thermal stability threshold significantly. Additionally, the nonlinear zinc oxide material characteristics influence the thermal stability threshold strongly. Furthermore, a thermal stability prediction approach based on few, computationally less expensive simulations is proposed. Finally, the results are confirmed for an arrester model that is equipped with a field-grading system. The paper shows that the presented field simulation approach can be reliably used to determine the stability threshold of an arrester, thus, reducing the need for costly laboratory tests.
      PubDate: April 2022
      Issue No: Vol. 37, No. 2 (2022)
       
  • Impact of Strength and Proximity of Receiving AC Systems on Cascaded
           LCC-MMC Hybrid HVDC System

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      Authors: Yongjie He;Wang Xiang;Binye Ni;Xiaojun Lu;Jinyu Wen;
      Pages: 880 - 892
      Abstract: The cascaded hybrid LCC-MMC inverter is considered as a feasible option to mitigate the commutation failure problem of conventional LCC-HVDC while maintaining bulk power transmission capability. However, the coupling between different types of converters may result in instability when the inverter integrates with weak AC systems. This paper establishes a small-signal model of the cascaded LCC-MMC inverter based hybrid HVDC system and validates the model against PSCAD/EMTDC. Through eigenvalue analysis, the impact of the strength and proximity of receiving AC systems on the small-signal stability is investigated, and the stable zone of the strength of receiving AC systems is identified. Besides, a supplementary coupling mitigation control is proposed to tackle the instability problem under weak AC systems integration. Both analytical results and time-domain simulations demonstrate the validity of the supplementary control.
      PubDate: April 2022
      Issue No: Vol. 37, No. 2 (2022)
       
  • Data-Driven Fault Detection and Classification for MTDC Systems by
           Integrating HCTSA and Softmax Regression

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      Authors: Jiapeng Li;Guobing Song;Jifei Yan;Yujun Li;Zhao Xu;
      Pages: 893 - 904
      Abstract: The requirement of fast fault isolation poses a great challenge to the safe operation of multi-terminal direct current (MTDC) systems. In order to make a better tradeoff between the speed and reliability of the protection scheme, it is imperative to mine more valuable information from fault transient signals. This paper puts forward a data-driven framework capable of digging out and synthesizing multi-dimensional features to achieve fast and reliable DC fault detection and classification in MTDC systems. Highly comparative time-series analysis (HCTSA) is first adopted to extract extensive features with clear physical interpretations from fault current waveforms, and a few features valuable to fault identification are then selected utilizing the greedy forward search. Based on the reduced features, a softmax regression classifier (SRC) is further proposed to calculate the probability of each fault category with a relatively minor on-line computational burden. Numerical simulations carried out in PSCAD/EMTDC have demonstrated the proposed approach is effective under different fault conditions, robust against noise corruptions as well as abnormal samplings, and replicable in various DC grids. In addition, comprehensive comparison studies with conventional derivative-based protection methods and some typical artificial intelligence based (AI-based) methods have been conducted. It is verified that the proposed method has the advantages of higher fault identification accuracy over conventional protections and shallow structure AI-based methods, better interpretability as well as lower on-line computing complexity over the deep architecture AI-based approaches.
      PubDate: April 2022
      Issue No: Vol. 37, No. 2 (2022)
       
  • Removal of System and CT Decaying DC Component in Fault Signal Using
           Selective Interval Integration

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      Authors: Sadegh Jamali;Hamid Zamani;
      Pages: 905 - 912
      Abstract: The fundamental current component at the secondary side of current transformer (CT) is often accompanied with decaying direct current (DC) component produced by the system and the CT. The discrete Fourier transform (DFT) is known as a powerful tool in digital protection for estimation of the fundamental component in the presence of harmonics. The decaying DC component, unlike harmonics, is not limited to a distinct frequency but include a wide range of low frequencies affecting the DFT output by undesirable oscillations. This paper proposes a method based on two selective interval integration for accurate estimation and elimination of the decaying DC component from the fundamental component of fault current. The two data intervals are separated by half a cycle minus one interval. The proposed algorithm is first tested using data derived by mathematical formulation under different conditions such as sampling frequency, noise, and characteristics of the DC component. The algorithm is also tested by simulation study using PSCAD/EMTDC for different fault conditions in a typical transmission system. In order to test the algorithm performance for practical applications, a Mho distance relay is simulated in the Matlab/Simulink environment. All the test cases verify efficiency, accuracy and speed of the proposed algorithm.
      PubDate: April 2022
      Issue No: Vol. 37, No. 2 (2022)
       
  • An FTU-Based Method for Locating Single-Phase High-Impedance Faults Using
           Transient Zero-Sequence Admittance in Resonant Grounding Systems

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      Authors: Jie Li;Yinliang Liu;Chengxin Li;Dehui Zeng;Haifeng Li;Gang Wang;
      Pages: 913 - 922
      Abstract: A novel fault location scheme using feeder terminal units (FTUs) for high-impedance grounding faults in resonant grounding systems (RGSs) is presented. The parallel resonance for a high-impedance fault (HIF) in an RGS with inverter-interfaced distributed generators (IIDGs) is analyzed. The process exhibits unique distribution features for transient zero-sequence components involving underdamped and overdamped states. We conclude that the transient zero-sequence admittances (TZSAs) from FTUs upstream of the fault point have the maximum value, while the TZSAs obtained from FTUs downstream of the fault point are small for HIFs. Therefore, the proposed location scheme uses FTUs to calculate the maximum values of the TZSA. By comparing with action criteria, the distribution automation (DA) master station utilizes the above results of each FTU to locate the faulty feeder section. The accuracy of the fault characteristics and the proposed method are validated by applying a real-time digital simulator (RTDS) and an FTU-based monitoring system. Additionally, the proposed scheme demonstrates an excellent and reliable performance, considering various faulty feeder sections, fault resistances, arcing faults, fault inception angles, imbalances and the presence of IIDGs and noise.
      PubDate: April 2022
      Issue No: Vol. 37, No. 2 (2022)
       
  • Nonlinearity Characteristic of High Impedance Fault at Resonant
           Distribution Networks: Theoretical Basis to Identify the Faulty Feeder

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      Authors: Mingjie Wei;Hengxu Zhang;Fang Shi;Weijiang Chen;Vladimir Terzija;
      Pages: 923 - 936
      Abstract: Feeder identification is indispensable for distribution networks to locate faults at a specific feeder, especially when measuring devices are insufficient to locate faults more precisely. For the high impedance fault (HIF), the feeder identification is much more challengeable and related approaches are still in the early stage. This paper thoroughly reveals the nonlinearity characteristics of different feeders when a HIF happens at a three-wire system that is with the resonant grounded neutral (RGN). Firstly, the diversity of nonlinearity existing in HIFs is explained from the perspective of energy. Then, the nonlinearity of zero-sequence current that differs between healthy and faulty feeders are deduced theoretically. Effects of the detuning index of Petersen coil, the damping ratio of system, and the length of feeder are all considered. Afterward, these theoretical conclusions are verified by the HIF cases experimented in a real 10kV system. Finally, after indicating the problems of a classic phase-relationship-based algorithm, we suggest an improved method based on the phase differences between the harmonic currents of different feeders. The effectiveness of the method has been verified.
      PubDate: April 2022
      Issue No: Vol. 37, No. 2 (2022)
       
  • Attenuation Characteristics and Time Delay of PD Electromagnetic Wave
           Propagation in GIS Systems

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      Authors: Tao Zhao;Martin D. Judd;Brian G. Stewart;
      Pages: 937 - 946
      Abstract: Modeling of electromagnetic wave propagation inside a gas-insulated switchgear structure can be helpful for understanding and improving the utilization of partial discharge detection by providing information to help determine more optimal positioning of ultra-high frequency sensors. This paper studies the effect of insulating spacers, L- and T-type structures on electromagnetic wave propagation by simulating the time dependent wave propagation behavior for these arrangements within a gas-insulated switchgear busbar geometry. The attenuation characteristics and time delays produced by spacers, L- and T-type structures for partial discharge electromagnetic wave propagation behavior are presented. Emphasis is placed on comparison of attenuation characteristics and time delay between different observation points along the busbar both before and after the 90° bends formed by L- and T-type structures. Moreover, a comparative analysis of the radial electric field at the gas-insulated switchgear tank and its rate of change with time is also conducted. The paper demonstrates that if the location of the ultra-high frequency sensor is chosen appropriately based on knowledge of the physical structures, the attenuation effects introduced by L- and T-type structures could be reduced.
      PubDate: April 2022
      Issue No: Vol. 37, No. 2 (2022)
       
  • A Robust Multi-Layer Framework for Online Condition Assessment of Power
           Transformers

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      Authors: Seyed-Alireza Ahmadi;Majid Sanaye-Pasand;
      Pages: 947 - 954
      Abstract: Online continuous monitoring of dissolved gasses in transformer oil has become an emerging trend in the recent years. This way, in addition to sending the warning signal in the case of gas concentration, a fault diagnosis procedure can be conducted using standard Dissolved Gas Analysis (DGA) methods. However, since the fault diagnosis outcome and result of these methods are sometimes different, an appropriate solution should be suggested to accurately describe the transformer internal condition. To do so, a robust multi-layer framework has been proposed in this paper. Handling the measurement uncertainties and fusing the results of independent DGA methods without losing their diagnosis resolutions are the interesting features of this framework. To improve the overall accuracy of fused diagnosis result, an artificial neural network-based approach is proposed. It intelligently assigns the weight of each independent method in the fusion procedure according to its fault type detection accuracy for the range of input gasses concentrations. To evaluate performance of the proposed framework, comprehensive test studies have been conducted and the promising obtained results prove its superior performance for use in online applications.
      PubDate: April 2022
      Issue No: Vol. 37, No. 2 (2022)
       
  • A New Model for Human Body Impedance

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      Authors: Geoffrey Pritchard;
      Pages: 955 - 959
      Abstract: The impedance of the human body is strongly voltage-dependent, and exhibits substantial variation among individuals. We introduce a new statistical model that separates body impedance into three terms (internal tissue, skin, and contact impedances in series). Advantages over simpler models include a physically plausible monotonicity with respect to voltage and the ability to simulate the impedance characteristics of individuals.
      PubDate: April 2022
      Issue No: Vol. 37, No. 2 (2022)
       
  • Resilient Protection of Medium Voltage DC Microgrids Against Cyber
           Intrusion

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      Authors: Vaibhav Nougain;Sukumar Mishra;Sushree Subhasmita Jena;
      Pages: 960 - 971
      Abstract: Differential current protection has been a reliable approach for line protection in DC systems. However, due to its dependence on communication for terminal current information, resiliency of such a protection approach is poor against external cyber intrusions (ECI) of different types, i.e., false data injection (FDI) and time synchronization attacks (TSA). As a result of which, the system is prone to collapse due to line tripping in the presence of coordinated ECIs. The scope of this paper is to propose a resilient protection approach for medium voltage DC (MVDC) microgrids differentiating between the real faults and the ECIs in a system. The approach also detects ECIs on an adjacent line occurring simultaneous to a real fault where the system deploys current limiting reactors (CLR) which have the function of limiting the peak of fault current. Modal transformation is carried out to obtain the line-mode and zero-mode voltage across these CLRs. The mode voltages across the faulty mode networks are utilised along with differential current protection to propose a resilient protection approach against ECIs, which is sensitive to high impedance faults (HIFs), working well in the presence of White Gaussian Noise (WGN) in measurement. Further, a sensitivity function is formulated which gives the variation of decisive variables i.e., line-mode voltage and zero-mode voltage with respect to change in decisive parameters i.e., fault resistance and fault location in the system.
      PubDate: April 2022
      Issue No: Vol. 37, No. 2 (2022)
       
  • Assessing the Superhydrophobic Performance of Laser Micropatterned
           Aluminium Overhead Line Conductor Material

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      Authors: Chengxing Lian;Christopher Emersic;Fatema H. Rajab;Ian Cotton;Xu Zhang;Robert Lowndes;Lin Li;
      Pages: 972 - 979
      Abstract: Overhead electric supply lines are subject to water and ice accumulation, causing noise and weight increase, and leading to faults or failures. In this research, micro-textures were laser-ablated on aluminium substrates representative of overhead line conductors to achieve superhydrophobic properties. Samples were then subjected to a range of tests to measure the resilience and durability of such surfaces to conditions experienced by overhead line conductors. Tests to examine thermal ageing, thermal cycling, UV exposure, long term ambient outdoor environment exposure, and corona exposure testing were conducted and the evolution of surface superhydrophobicity was quantified. A high degree of resilience was observed for most of the testing. The feasibility of manufacturing upscale is discussed in addition to optimising test methods.
      PubDate: April 2022
      Issue No: Vol. 37, No. 2 (2022)
       
  • Active Fault Current Limitation for Low-Voltage Ride-Through of Networked
           Microgrids

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      Authors: Xubin Liu;Xinyu Chen;Mohammad Shahidehpour;Canbing Li;Qiuwei Wu;Yuhang Wu;Jinyu Wen;
      Pages: 980 - 992
      Abstract: With the continuously increasing penetration of networked microgrids (MGs) on the local utility grid (UG), MGs face the challenge to avoid increasing system fault currents during low-voltage ride-through (LVRT). To solve this challenge, an active fault current limitation (AFCL) method is proposed with three parts: 1) a novel phase angle adjustment (PAA) strategy is conducted to relieve the impact of MGs output fault current on system fault current; 2) the current injection (CI) strategy for LVRT is formulated to fit the function of PAA; 3) a novel converter current generation (CCG) strategy is developed to achieve a better voltage support ability by considering network impedance characteristics. The proposed AFCL method is applied to the back-to-back converter, as a connection interface between MGs and UG. Extensive tests and pertinent results have verified the improvements of proposed AFCL method with better LVRT performance, while the networked MGs output fault current does not increase the amplitude of system fault current.
      PubDate: April 2022
      Issue No: Vol. 37, No. 2 (2022)
       
  • Hybrid Multiterminal HVDC System Based on Line-Commutated and Alternate
           Arm Converters

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      Authors: Pingyang Sun;Harith R. Wickramasinghe;Georgios Konstantinou;
      Pages: 993 - 1003
      Abstract: Challenges in long distance power transmission and large-scale integration of renewable energy systems drive the development of high-voltage direct current (HVDC) systems. HVDC systems can be configured as combinations of line-commutated converters (LCCs), voltage source converters (VSCs) and hybrid systems. However, each hybrid configuration poses its own challenges and requires unique control. Thus, it is necessary to explore other possible configurations, especially different configurations in more complex hybrid multiterminal DC (MTDC) systems and future dc grids. This article develops the steps for integration of alternate arm converters (AACs) in hybrid MTDCs and demonstrates the operation of AACs in a hybrid MTDC system. The detailed system structure and control hierarchy are developed. The performance of the hybrid MTDC system under multiple operating scenarios including ac and dc faults are demonstrated, verifying the feasibility of an LCC and AAC-based hybrid MTDC system.
      PubDate: April 2022
      Issue No: Vol. 37, No. 2 (2022)
       
  • High-Impedance Fault Detection Method Based on Stochastic Resonance For a
           Distribution Network With Strong Background Noise

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      Authors: Xiaowei Wang;Xiangxiang Wei;Jie Gao;Guobing Song;Mostafa Kheshti;Liang Guo;
      Pages: 1004 - 1016
      Abstract: When a high-impedance fault (HIF) occurs in a distribution network, the fault current is very weak and can be easily confused with capacitor switching (CS), load switching (LS) or inrush current (IC). This can lead to an inaccurate judgment of current protection. Furthermore, when the external noise is too strong, the above problems become more prominent. To address these problems, this paper, based on the build-up characteristics of HIF current, proposes a novel method combining stochastic resonance (SR) using noise and variational mode decomposition (VMD). First, SR is used to detect the transient zero-sequence current in strong background noise and obtain the output current. Second, VMD is adopted to decompose the output current, and low-frequency and high-frequency intrinsic mode functions (IMFs) are obtained. Then, kurtosis and skewness values are calculated to construct the starting and identification criteria, respectively. Finally, when the kurtosis value is greater than 3.0, the protection device is started, and then, when the skewness value is less than 0, that is, when negative skewness occurs, it is judged as a HIF; conversely, when the skewness value is greater than 0, that is, when positive skewness occurs, it is judged as CS, LS or IC. A large number of tests show that the method can realize accurate identification in strong background noise with an SNR = −10 dB.
      PubDate: April 2022
      Issue No: Vol. 37, No. 2 (2022)
       
  • Open-Circuit Fault Characteristics and Location Methods of Switch Elements
           For Cascaded Power Electronic Transformers

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      Authors: Jiexiang Han;Zhe Zhang;Qinghua Lai;Xianggen Yin;
      Pages: 1017 - 1026
      Abstract: Power electronic transformers (PETs) play an important role in AC/DC hybrid distribution networks. However, the fault probability of a PET is higher because of the use of many power electronic devices. The short-circuit protection of a PET is relatively mature, but studies on its open-circuit faults are limited to insulated gate bipolar transistors (IGBTs) in the cascaded H-bridge (CHB). Therefore, other types of open-circuit faults result in dead zones in the fault location process. In this article, the open-circuit fault characteristics of switch elements at different positions of a PET are analyzed, and a protection circuit is designed for the possible overvoltage caused by the open-circuit fault in the CHB. Moreover, the fault location methods of switch element open-circuit faults are proposed. The proposed methods could adapt to the diversity of control modes, power directions and load levels. The correctness and effectiveness of the methods are verified via simulation tests. This work provides a basis for the implementation of fault-tolerant control and protection of PETs.
      PubDate: April 2022
      Issue No: Vol. 37, No. 2 (2022)
       
  • A Composite Strategy for Improved Power Quality Using Micro Compensators
           in Secondary Distribution Systems

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      Authors: Jino M. Pattery;Sandeep Jayaprakasan;Elizabeth P. Cheriyan;Rijil Ramchand;
      Pages: 1027 - 1035
      Abstract: This paper introduces a micro compensator which is installed and maintained by an electric utility for improved power quality in low voltage secondary distribution systems. Envisaged as a shunt-connected current-controlled voltage source inverter at 400 V level, a micro compensator performs reactive and harmonic compensation during peak periods. Hence the power factor and the power quality at the point of common coupling are improved. During off-peak periods, a micro compensator provides dynamic reactive current support to compensate for voltage sag or voltage swell. The weighing factors which regulates the contribution of each compensation are quantitatively derived from voltage measurements at the point of common coupling. The proposed method to calculate reactive and harmonic compensation indices is validated in realistic systems. Frequency domain analysis shows that the harmonic compensation can be achieved in both static and dynamic modes. Analytical predictions based on frequency domain analysis are verified with experimental results which shows notable improvement in power quality levels.
      PubDate: April 2022
      Issue No: Vol. 37, No. 2 (2022)
       
  • Adaptive Damping Control of Subsynchronous Oscillation in DFIG-Based Wind
           Farms Connected to Series-Compensated Network

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      Authors: Jan Shair;Xiaorong Xie;Jianjun Yang;Jingyi Li;Haozhi Li;
      Pages: 1036 - 1049
      Abstract: The frequency of subsynchronous oscillation (SSO) in doubly-fed induction generator (DFIG)-based wind farms connected to series-compensated networks is determined by system-wide operating conditions, including the wind speed, number of in-service wind turbines, and degree of series-compensation. This paper proposes an adaptive mitigation scheme to damp the SSO for a full range of subsynchronous frequency variations due to different operating conditions. The proposed scheme comprises 1) a subsynchronous frequency estimator (SSFE) and 2) an adaptive subsynchronous damping controller (ASDC). The SSFE detects the SSO mode and tracks its subsynchronous frequency accurately. The ASDC utilizes voltage signals to extract the SSO at the estimated subsynchronous frequency, generates appropriate current signals, and injects them into the grid through a shunt-voltage sourced converter (SVSC). The ASDC behaves like a variable impedance, which essentially reshapes the system's impedance response by adding a positive resistance at the estimated subsynchronous frequency. The parameters of the phase-shifters are computed using Brent's root-finding method such that the desired phase-shift at the estimated subsynchronous frequency is always maintained. The control's adaptiveness and damping performance under different operating scenarios is verified through extensive EMT simulations on a real-world wind power system facing SSO using PSCAD.
      PubDate: April 2022
      Issue No: Vol. 37, No. 2 (2022)
       
  • Temporary Detuning of Cablified Transmission Grids for Mitigation of
           Resonant Overvoltages

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      Authors: Oscar Lennerhag;Jan Lundquist;Math H. J. Bollen;
      Pages: 1050 - 1057
      Abstract: Changes in the power system such as an increased use of cables in transmission systems lead to lower resonance frequencies, a possible consequence being an increased risk for resonant overvoltages. This paper presents a method for protecting the power system from resonant overvoltages caused by transformer energization or fault clearing in the vicinity of large transformers. The method utilizes disconnection of cables according to a predetermined scheme that shifts the system resonance in case the harmonic voltage exceeds a threshold. Compared to other available mitigation measures, the proposed method is inexpensive, robust, and acts only when needed, thereby minimizing any impact during normal operation. The method is exemplified using a realistic network model in PSCAD, showing that by employing the method it is possible to reduce the duration of the overvoltages, and thereby the stress on surge arresters and other equipment.
      PubDate: April 2022
      Issue No: Vol. 37, No. 2 (2022)
       
  • P Class and M Class Compliant PMU Based on Discrete-Time Frequency-Gain
           Transducer

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      Authors: Krzysztof Duda;Tomasz P. Zieliński;
      Pages: 1058 - 1067
      Abstract: Phasor Measurement Units (PMUs) are widely used in the Smart Grids (SGs). In this paper we propose the discrete-time frequency-gain transducer (DTFGT) and we apply it for PMU implementation. The DTFGT is a general-purpose, short-cycle, leakage-free, computationally feasible, frequency estimator that exploits gain slope of a Finite Impulse Response (FIR) filter frequency response. The proposed PMUs inherit the features of the DTFGT and are compliant in Protective class (P) and Measurement class (M) of the IEC/IEEE 60255-118-1 standard. Comparison with other FIR based PMUs highlights advantages of the proposed solution such as high accuracy, good noise immunity, short response time and simple implementation.
      PubDate: April 2022
      Issue No: Vol. 37, No. 2 (2022)
       
  • Vibration and Noise Characteristics of Air-Core Reactor Used in HVDC
           Converter Stations

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      Authors: Lu Gao;Shengchang Ji;Lingyu Zhu;Hang Yang;Fan Zhang;Jinyu Li;Sisi Hui;
      Pages: 1068 - 1077
      Abstract: Air-core reactors used in filters are significant equipment in HVDC converter stations. They are among the most serious noise sources under the action of multi-frequency magnetic forces. The vibration and noise characteristics of air-core reactors are investigated in this paper, which is the basis for noise control of HVDC projects. Firstly, based on the characteristics of magnetic forces, the generation process of vibration is analyzed theoretically. Then, Experimental Modal Analysis (EMA) is conducted and the results indicate that multiple natural frequencies exist and their mode shapes contain distinct peaks and troughs. Vibration shapes are also measured under different excitation frequencies with dense measuring points over the winding surface. The measured vibration shapes are consistent with the corresponding mode shapes. Furthermore, the noise distribution characteristics are analyzed by Boundary Element Method (BEM). The simulation results show that the noise radiation has obvious directional effect, which are mainly dominated by the corresponding vibrations and mode shapes. Based on the results of this paper, some suggestions for noise reduction are given in the last.
      PubDate: April 2022
      Issue No: Vol. 37, No. 2 (2022)
       
  • Fourier Enhanced Charge Simulation Method for Electrostatic Analysis of
           Overhead Transmission Lines

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      Authors: Jon T. Leman;Robert G. Olsen;
      Pages: 1078 - 1087
      Abstract: A computationally efficient charge simulation method is developed for three-dimensional electrostatic calculations involving parallel high voltage transmission conductors near a cloud of point charges. The conductors are modeled using axial line charge density segments, each with linearly varying charge density. A typical problem involves solving for the line charge densities and point charge values given the system geometry and voltage boundary conditions. The method was developed to support ongoing research into high voltage transmission line optimization using the external electric field to link transmission capacity and switching impulse flashover. The method uses superposition and applies Fourier principles to reduce computational burden by moving portions of the problem to the spatial frequency domain. Computation time can be significantly reduced relative to an all-spatial charge simulation approach. Examples involving bundled transmission conductors show measured computation time improvement and compare space potential and electric field results to those obtained from finite element analysis.
      PubDate: April 2022
      Issue No: Vol. 37, No. 2 (2022)
       
  • Fast Resilience Assessment of Distribution Systems With a
           Non-Simulation-Based Method

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      Authors: Gang Zhang;Feng Zhang;Xiaoyu Wang;Xin Zhang;
      Pages: 1088 - 1099
      Abstract: Traditional simulation-based method for resilience assessment of distribution systems is very time consuming since the network topology is characterized with a large number of scenario-specific optimization models. In this paper, we propose a methodology for fast resilience assessment of distribution systems with a non-simulation-based method, which can significantly improve the assessment accuracy and computational efficiency. First, a probabilistic metric is proposed to assess the system resilience against extreme events, which quantifies the system performance starting from the pre-event stage to the post-event stage. Then, a mixed-integer linear programming (MILP) is proposed to model the energization paths (EPs) with binary decision variables. Subsequently, the resilience metric-related probability events are built using the EPs. Last, the probabilistic resilience metric is explicitly expressed based on the total probability formula, conditional probability formula and EP-topology simplification methods. In the proposed method, the topology evolution along with the system degradation, restoration (part healed) and recovery (all healed) is characterized with a non-simulation-based method, rather than the multiple scenarios in traditional methods. The numerical tests validate the effectiveness of the proposed method and superiority over the simulation-based approach.
      PubDate: April 2022
      Issue No: Vol. 37, No. 2 (2022)
       
  • Thermal and Electrical Characteristics of Hollow Former With Fault Current
           Limiting Function for Superconducting Power Cable

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      Authors: Yojong Choi;Seunghyun Song;Junseong Kim;Yeon Suk Choi;Tae Kuk Ko;
      Pages: 1100 - 1108
      Abstract: A superconducting fault current limiting cable (SFCLC) with a hollow former is composed of various elements with different electrical and thermal properties, including liquid nitrogen inside the former. This type of cable can be used to mitigate the impact of short-circuit faults. This paper introduces a computational model that combines thermal and electrical behavior to investigate the thermal and electrical characteristics of SFCLCs according to the composition of a hollow former. To verify the computational model, a superconducting power cable with a hollow former was fabricated and a fault current test was performed. Good agreement was obtained between the calculation results obtained from the proposed computational model and the fault current test results. In addition, using the proposed computational model, the relationship between increases in temperature and limitations on current was analyzed for each configuration of the former according to the length of the cable and the duration of the fault. The characteristic analysis provides information on the hollow former composition that most effectively limits the fault current, depending on the length of the cable and the duration of the fault. The results can be used to determine the material and dimension of the hollow former for SFCLCs design.
      PubDate: April 2022
      Issue No: Vol. 37, No. 2 (2022)
       
  • An Improved DC Line Fault Detection Scheme Using Zone Partition for MTDC
           Wind Power Integration Systems

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      Authors: Saizhao Yang;Wang Xiang;Jinyu Wen;
      Pages: 1109 - 1119
      Abstract: The MMC based DC grids are an effective solution to integrate bulk wind power. Under DC faults, the wind power is continuously fed into DC grids, resulting in large fault currents. To guarantee the uninterrupted and safe operation of healthy parts, DC faults should be detected and isolated selectively. Most existing DC fault detection schemes rely on large current-limiting reactors (CLR) to guarantee high selectivity. The reliability of them will be deteriorated under weak boundary conditions. Besides, some schemes fail to identify close-in faults. Though fault detection schemes independent of CLRs are proposed, they cannot work well for remote faults. Hence, to protect the entire transmission line with smaller CLRs, an improved DC fault detection scheme using zone partition is proposed. Firstly, according to different fault distances, internal faults are partitioned into four zones along the transmission line. The fault characteristics in different zones are analyzed. Then, the polarities and arrival times of traveling-waves are used to design the criteria dedicated to different zones. The proposed method is endurable to fault resistance and noise disturbance. Simulation results show that the MTDC wind power integration systems can operate safely during DC fault isolation.
      PubDate: April 2022
      Issue No: Vol. 37, No. 2 (2022)
       
  • Permanent Fault Location for Three-Core Cable Using Multiconductor
           Coupling Model

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      Authors: Zehua Tang;Peng Zhang;Rui Liang;Nan Peng;Menghan Cheng;Yujiao Qiao;
      Pages: 1120 - 1129
      Abstract: Phase-to-ground faults in underground cables are usually correlated with the metallic sheaths. This work proposes a fault location method for the three-core cable in distribution system using voltage and current measurements at the both terminals. First, a generic model for the three-core cable with independent sheath is constructed by lumped parameter approach. Then, considering the practical measurement restrictions, a simplified yet effective equivalent circuit is proposed on the basis of the generic model. Additionally, the analysis of the earthed strap current is presented. The earthed strap current is used to determine cable fault distance by voltage and current equations. By PSCAD/EMTDC, an effectiveness evaluation of the proposed model is given, and the performance of the proposed algorithm is investigated with extensive fault simulations. The results demonstrate the method is not affected by different fault conditions. Finally, the comparison with other algorithms shows higher accuracy and feasibility of the proposed method for a three-core cable with independent sheath.
      PubDate: April 2022
      Issue No: Vol. 37, No. 2 (2022)
       
  • Grounding System Analysis of 220 kV Power Cable Lines Installed Underneath
           a Bridge

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      Authors: Xing Xu;Xiangrong Chen;Fanbo Meng;Ashish Paramane;
      Pages: 1130 - 1139
      Abstract: Power cables installed underneath the bridge have become vital in the cross-sea power transmission system. The design of grounding system is a decisive factor which determines the safety and reliability of these cables. In this paper, the nodal admittance matrix of the cable system is established considering the influence of the overhead laying condition and the coupled line model is used to improve the calculation efficiency. A matrix solution method, which can greatly reduce the dimension of the nodal equation, is proposed for the steady-state analysis of the grounding system. The grounding system designed for 220 kV cable project of Zhoudai Bridge in Zhejiang Province of China is also investigated. The results show that, compared with the induced voltage, the circulating current is the main factor affecting the ampacity of the cable system. Connecting the impedance at the cable joint can effectively reduce the power loss caused by circulating currents. A guideline for the grounding system design of the power cable lines installed underneath a bridge is proposed in this paper.
      PubDate: April 2022
      Issue No: Vol. 37, No. 2 (2022)
       
  • Under-Frequency Load Shedding in a Standalone Power System With
           Wind-Turbine Generators Using Fuzzy PSO

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      Authors: Ying-Yi Hong;Chih-Yang Hsiao;
      Pages: 1140 - 1150
      Abstract: Under-frequency load shedding maintains a power grid resilient against a severe contingency. The under-frequency relay (such as 81L) with pre-determined settings is used to prevent blackout in the power grid by detecting a decreasing system frequency. In this work, the shed load and frequency setting at each stage for the 81L relay are determined in an offshore standalone power grid with wind power turbines. Possible scenarios including “N-2-2” outages and “N-3” outages as well as Markov models of diesel and wind generators are investigated. The total shed load is minimized and the frequency nadir is maximized using Takagi-Sugeno (TS)-based particle swarm optimization (PSO). Two sets of TS fuzzy rules are developed to tune the inertia weight and learning factors in the proposed PSO to obtain the optimal settings. A 31-bus standalone power grid with two wind turbines of 2×2 MW was studied to reveal the applicability of the proposed method.
      PubDate: April 2022
      Issue No: Vol. 37, No. 2 (2022)
       
  • Mathematical Study on Traveling Waves Phenomena on Three Phase
           Transmission Lines – Part I: Fault-Launched Waves

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      Authors: Fernando Marinho de Magalhães Júnior;Felipe V. Lopes;
      Pages: 1151 - 1160
      Abstract: A mathematical study on the traveling waves (TWs) propagation phenomena on three-phase power lines under fault conditions is presented in this article. This article is divided into two parts, and this part focuses on the analytical development of expressions that describe fault-launched TWs as functions of line and fault parameters. From the obtained mathematical representation of TWs launched by faults, TW-based applications can be designed in a more reliable way, justifying the relevance of the presented study.
      PubDate: April 2022
      Issue No: Vol. 37, No. 2 (2022)
       
  • Mathematical Study on Traveling Waves Phenomena on Three Phase
           Transmission Lines – Part II: Reflection and Refraction Matrices

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      Authors: Fernando Marinho de Magalhães Júnior;Felipe V. Lopes;
      Pages: 1161 - 1170
      Abstract: In this paper, the study initiated in its first part on traveling waves (TWs) launched by faults on three-phase transmission lines is continued, with major focus on TW reflection and refraction coefficient matrices at line terminations and fault point. By doing so, mathematical expressions that represent the behavior of reflected and refracted voltage and current TWs are obtained in modal domain, for all fault types, allowing the proper estimation of wavefronts measured at the line terminals. Hence, once the amplitude and polarity of wavefronts measured at the line terminals can be estimated for specific fault features, the setup of TW detection thresholds and polarity evaluation schemes can be enhanced in practical applications. To demonstrate the validity of the obtained results, the Alternative Transients Program (ATP) is used to simulate fault-induced transients, from which several TWs are analyzed to compare the obtained analytical mathematical wavefront representation with those verified in the assessed fault records. From the obtained results, the mixing mode phenomena is proven, and the TW reflection and refraction matrices are validated, highlighting the usefulness of the presented mathematical study during the development of modern TW-based applications.
      PubDate: April 2022
      Issue No: Vol. 37, No. 2 (2022)
       
  • Investigation on the Implementation of the Single-Sheath Bonding Method
           for Power Cables

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      Authors: Xi Wang;Jing Yong;Lulu Li;
      Pages: 1171 - 1179
      Abstract: Sheath bonding is an essential requirement for transmission and distribution cables. Three bonding methods are widely used in industry at present: solid bonding, single-point bonding, and cross bonding. The latter two are for solving the ampacity reduction problem caused by solid bonding. This paper presents an in-depth investigation of a new cable sheath bonding method called single-sheath bonding. The new method uses one of the cable sheaths as the return path for the fault current and thus eliminates the need for the ground continuity conductor (GCC). In this paper, various configurations to implement the single-sheath bonding method are proposed. Their performances are comprehensively evaluated and compared with those of the existing bonding methods through simulation and sensitivity studies. The results show that single-sheath bonding can achieve a similar performance of either single-point bonding or cross bonding with a lower cost. Therefore, single-sheath bonding can be an alternative to single-point bonding and cross bonding. The potential applications of the single-sheath bonding method are also clarified in the paper.
      PubDate: April 2022
      Issue No: Vol. 37, No. 2 (2022)
       
  • Cost-Effectiveness Enhancement in Distribution Networks Protection System
           Planning

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      Authors: Wandry Rodrigues Faria;Ciniro Aparecido Leite Nametala;Benvindo Rodrigues Pereira Júnior;
      Pages: 1180 - 1192
      Abstract: The allocation of protective and controlling devices in distribution networks is a well-known optimization problem that has been addressed for over 20 years, while the coordination of these devices became a crucial issue in the last decade due to the insertion of distributed generators in the systems. Prior researches have proposed either solving the allocation considering coordination indications or the decoupled approach of these problems. However, the first is not suitable for active systems, and the latter fails to achieve high-quality solutions due to topology changes during the coordination adequation. This paper presents an optimization model that combines both allocation and coordination as a single problem, considering technical and economic aspects. We consider the system’s uncertainties and the generators’ limits of current injection during fault situations. The proposed methodology also allows planning the protection system considering only the most common fault scenarios. The sitting of devices is handled by a genetic algorithm, while the coordination is guaranteed by a linear model that runs within the metaheuristic. The tool is tested for a real 135-bus distribution system.
      PubDate: April 2022
      Issue No: Vol. 37, No. 2 (2022)
       
  • A Dynamic Synchrophasor Estimation Algorithm Considering Out-of-Band
           Interference

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      Authors: Ling Fu;Ling Yu;Siyu Xiong;Zhengyou He;Ruikun Mai;Xiaopeng Li;
      Pages: 1193 - 1202
      Abstract: The existence of out-of-band interference (OBI) signals in power systems will dramatically degrade the performance of synchrophasor estimation. In order to alleviate the influence of OBI, a hybrid phasor model is proposed, in which the OBI phasor and the dynamic fundamental phasor are expressed by Taylor series, respectively. Then, the rough fundamental frequency and OBI frequency estimation are achieved via the rough fundamental component and OBI component estimated from discrete Fourier transform (DFT). For attaining the accurate phasor, the proposed algorithm can invoke the corresponding coefficient matrices calculated off-line according to whether the power signal contains OBI or not. Finally, field data and computer-generated signals are used to assess the proposed algorithm performance. The results obtained indicate that the proposed algorithm can enhance phasor estimation performance by keeping maximum TVEs below 0.001% and 1% under frequency deviation and power modulation tests with OBI, respectively.
      PubDate: April 2022
      Issue No: Vol. 37, No. 2 (2022)
       
  • A High-Efficiency Method to Determine Parameters of High Impedance Arc
           Fault Models

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      Authors: Mingjie Wei;Fang Shi;Hengxu Zhang;Fan Yang;Weijiang Chen;
      Pages: 1203 - 1214
      Abstract: Numerical modeling of the high impedance arc fault (HIAF) is essential to supplementing the deficiency of real-world fault cases and extending the fault scenarios. Setting parameters of the model correctly is the basis to reproduce practical fault waveforms. According to the literature, the parameters of HIAF models are mostly determined manually and subjectively. The existing automatic methods of parameter determination are mostly used in the modeling of other types of arcs (such as DC arcs and circuit breaker arcs), which do not consider the connections with power networks. It will be time-consuming if directly applying these methods to the HIAF model with the connection of a power network. In this paper, after introducing the unique requirements in simulating the nonlinearity of HIAFs, a high-efficiency parameter determination method is proposed for HIAF models. The method is realized by interfacing the optimizer programmed in Python with the HIAF model and power network established in PSCAD. In this process, a combination of pulse controllers is designed and certain configurations are proposed, so that the parameter determination procedure can be significantly simplified. Case studies show that, by combining the proposed high-efficiency method with our previously proposed DIST-C HIAF model, fitting accuracy and efficiency can be guaranteed at the same time. The time for parameter determination of a HIAF model is only within minutes, decreasing hundreds of times and independent of the length of desired waveforms.
      PubDate: April 2022
      Issue No: Vol. 37, No. 2 (2022)
       
  • A Switching Times Reassignment-Based Voltage Balancing Strategy for
           Submodule Capacitors in Modular Multilevel HVDC Converters

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      Authors: Zhi Geng;Minxiao Han;Changjiang Xia;Longze Kou;
      Pages: 1215 - 1225
      Abstract: The capacitor voltage balancing algorithm (VBA) is an important issue to maintain the regular operation of modular multilevel converter (MMC). However, it requires a higher switching frequency to obtain a better balancing performance. In this paper, the VBA based on the reassignment of switching times is proposed to improve the balancing performance of capacitor voltages with a low operating frequency. The mechanism of the reduced switching frequency voltage balancing algorithm (RSFVBA) is presented. Based on that, the relationship among switching times, switching frequency, and capacitor voltage deviation is deduced. And then, the voltage deviations in the positive and negative intervals of the arm current are analyzed in detail. The RSFVBA proposed in this paper adjusts the switching times of SMs in different intervals of arm current to reduce the voltage deviation. Moreover, the proposed RSFVBA can also provide a low operating frequency because the reassignment of switching times does not change the total switching times in a line cycle. The feasibility of the proposed strategy is verified by simulation results in the professional tool Matlab/Simulink.
      PubDate: April 2022
      Issue No: Vol. 37, No. 2 (2022)
       
  • Application of the Transfer Matrix Approach to Direct Lightning Studies of
           Overhead Power Lines With Underbuilt Shield Wires—Part I: Theory

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      Authors: Erika Stracqualursi;Rodolfo Araneo;Jose Brandão Faria;Amedeo Andreotti;
      Pages: 1226 - 1233
      Abstract: This work is devoted to the analysis of voltages produced on overhead distribution lines hit by direct lightning. We will consider arbitrary terminations at both line ends and, also, arbitrary positioning of the pole being struck. We will deal with lines protected by shield wires, placed either above or below the phase conductors. The analytical tools chosen to deal with such complex system are the transfer matrix method and the theory of multiconductor transmission lines with periodic grounding. The innovation of an artificial symmetrical unit cell has been introduced to eliminate the need of two characteristic wave impedance matrices and to ease computation flow.
      PubDate: April 2022
      Issue No: Vol. 37, No. 2 (2022)
       
  • Application of the Transfer Matrix Approach to Direct Lightning Studies of
           Overhead Power Lines With Underbuilt Shield Wires—Part II: Simulation
           Results

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      Authors: Erika Stracqualursi;Rodolfo Araneo;Jose Brandão Faria;Amedeo Andreotti;
      Pages: 1234 - 1241
      Abstract: This work investigates voltages on overhead distribution lines produced by direct strokes, protected by shield wires, placed both above and below phase conductors. An improved formulation based on transfer matrix method and theory of multiconductor transmission lines with periodic grounding allows to eliminate the need of two characteristic wave impedance matrices. Based on the theoretical formulation developed in the first part of this work, as well as on the models there presented for the pole and grounding systems, we report here a wealth of simulation results concerning the line overvoltages subsequent to a pole being hit by lightning. Results are discussed considering a variety of factors, namely, position of the victim pole, type of load at both ends of the line, presence or absence of underbuilt shield wires, waveform of the lightning current, soil parameters and parameters of the frequency-dependent impedance of the pole grounding system. The good performance of the developed method is assessed by comparing our results with some EMTP-RV simulations. The transfer matrix method is then used to show the effect of shield wires in conjunction with periodic grounding: we assess the effects of terminations, frequency dependent models of the pole footing and grounding systems and frequency dependent models of lossy ground.
      PubDate: April 2022
      Issue No: Vol. 37, No. 2 (2022)
       
  • A Novel Signal Localized Convolution Neural Network for Power Transformer
           Differential Protection

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      Authors: Senthil Kumar Murugan;Sishaj P Simon;Rohit Rajan Eapen;
      Pages: 1242 - 1251
      Abstract: This paper presents a novel signal localized convolution neural network (SLCNN) for the power transformer differential protection. The distinct signal localization is performed with the convolution process sequentially on the frequency and time coefficients which are obtained from the wavelet decomposition of the differential current signal. The SLCNN is trained with a modified back-propagation algorithm according to SLCNN's architecture. Three power transformer test systems are considered for evaluation of the proposed SLCNN. The training patterns of each transformer are generated for various operating conditions. The SLCNN for each transformer is trained, validated and tested using its corresponding patterns. Then the performance of SLCNN is evaluated through confusion matrix analysis and is also compared with long short-term memory (LSTM) deep neural network, support vector machine (SVM), conventional back-propagation neural network (CBPNN) and conventional biased restraint second harmonic (CBSH) blocking method.
      PubDate: April 2022
      Issue No: Vol. 37, No. 2 (2022)
       
  • Indices of Intermittence to Improve the Forecasting of the Voltage Sags
           Measured in Real Systems

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      Authors: Michele De Santis;Leonardo Di Stasio;Christian Noce;Pietro Varilone;Paola Verde;
      Pages: 1252 - 1263
      Abstract: This paper provides a means of forecasting the future average performance a regional electric power system in terms of sags per year based on data accumulated over a four-year period. The paper also presents statistical analyses of the measured data. The sags measured in real systems consist of both rare voltage sags and grouped voltage sags (clusters); clusters are stochastic events that must be detected and removed to allow the estimation of the future performance based on a Poisson process. To detect and remove the clusters, new site indices of intermittence are proposed. These indices were measured in every site at which clusters were present, and the measurements included the frequency, time of grouping, and the large number of sags that constituted them. The performance of the forecast was evaluated by comparing the results obtained using the proposed indices with the results derived using a time filter equal for every site. The results showed that the forecast of the rare voltage using a few years' worth of field data had acceptable errors and was not prohibitive. The main aspect, which must be investigated further, is related to the choice of the best threshold on the intermittence site indices.
      PubDate: April 2022
      Issue No: Vol. 37, No. 2 (2022)
       
  • Novel Differential Protection Approach of UHV AC Transmission Lines Based
           on Tellegen's Quasi-Power Theorem

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      Authors: Shiming Liu;Bo Wang;Yongsen Zhao;L. L. Zhang;L. Jiang;
      Pages: 1264 - 1274
      Abstract: When current differential protection is applied to an AC transmission line, synchronous sampling at the two ends is required. The use of GPS synchronization increases the difficulty and cost of project implementation while the use of ‘ping-pong’ synchronization requires that the communication channel has equal transmission and reception delay. To overcome the impact of these issues, power differential protection has been proposed. However, power differential protection cannot fully identify the fault zone for solid single-line-to-ground fault. This paper proposes a novel differential protection approach based on the Tellegen's quasi-power theorem. The approach retains the advantages of current differential protection. Meanwhile, it is not affected by load condition and distributed capacitance. This paper also proposes a time synchronization method based on the Tellegen's quasi-power theorem to calculate and correct the time synchronization error. Therefore, the proposed pilot protection has a high synchronization accuracy and has no requirement on the communication delay. In this paper, different simulation models are established by using MATLAB/Simulink and PSCAD and extensive simulation studies verify the effectiveness of the proposed protection approach and time synchronization method.
      PubDate: April 2022
      Issue No: Vol. 37, No. 2 (2022)
       
  • Lightning Surge Analysis of Transmission Line Towers With a Hybrid
           FDTD-PEEC Method

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      Authors: Jinxin Cao;Yaping Du;Yuxuan Ding;Binghao Li;Ruihan Qi;Yang Zhang;Zhe Li;
      Pages: 1275 - 1284
      Abstract: This paper addresses lightning surges on the transmission systems with a new hybrid method, using a 1D FDTD model for the transmission line and a PEEC model for the tower and lightning channel. Compared with other circuit-based models, mutual coupling between the lightning channel and other parts in the system can be fully considered. This hybrid method has been validated numerically and experimentally, and good agreements are observed. This method then is applied to analyze the lightning surges on a 500 kV double-circuit transmission line system. It is found that the lightning channel has a significant impact on the surge response of the tower struck. Ignoring the coupling from the channel to the tower will weaken the hazard of lightning strikes. However, the influence of its coupling to the transmission line is not critical. The choice of interfacing points between these two models is then suggested. Furthermore, the influence of the tower footing is inves tigated. It is found that the insulator voltage is made of inductive and resistive components. The inductive component becomes dominant in the case of high soil conductivity and low grounding resistance. The voltage generally increases with decreasing soil conductivity and tends to decay slowly with time.
      PubDate: April 2022
      Issue No: Vol. 37, No. 2 (2022)
       
  • A Hybrid DC Fault Primary Protection Algorithm for Multi-Terminal HVdc
           Systems

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      Authors: Jingfan Sun;Suman Debnath;Matthieu Bloch;Maryam Saeedifard;
      Pages: 1285 - 1294
      Abstract: Protection against dc faults is one of the main technical hurdles faced when operating converter-based HVdc systems. Protection becomes even more challenging for multi-terminal dc (MTdc) systems with more than two terminals/converter stations. In this paper, a hybrid primary fault detection algorithm for MTdc systems is proposed to detect a broad range of failures. Sensor measurements, i.e., line currents and dc reactor voltages measured at local terminals, are first processed by a top-level context clustering algorithm. For each cluster, the best fault detector is selected among a detector pool according to a rule resulting from a learning algorithm. The detector pool consists of several existing detection algorithms, each performing differently across fault scenarios. The proposed hybrid primary detection algorithm: i) offers superior performance compared to an individual detector through a data-driven approach; ii) detects all major fault types including pole-to-pole (P2P), pole-to-ground (P2G), and external dc faults; iii) identifies faults with various fault locations and impedances; iv) is more robust to noisy sensor measurements compared to existing methods; v) does not require exhaustive simulation and sampling for training the model. Performance and effectiveness of the proposed algorithm are evaluated and verified based on time-domain simulations in the PSCAD/EMTDC software environment. The results confirm satisfactory operation, accuracy, and detection speed of the proposed algorithm under various fault scenarios.
      PubDate: April 2022
      Issue No: Vol. 37, No. 2 (2022)
       
  • Impact Loads on Tension Composite Multi-Strings of Insulator After a
           Single String Breaks

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      Authors: Bin Liu;Danyu Li;Caolan Liu;Jiajun Si;
      Pages: 1295 - 1303
      Abstract: The dynamic impact load after a single insulator of a tension composite multi-strings of insulator (MSI) set has failed is a key factor that should be considered in design. In this paper, an experimental method to obtain the dynamic tensile impact factor (DTIF) is established by considering a typical double-strings set, which is commonly used in practical engineering. A nonlinear numerical simulation method based on the finite element model, which is convenient for cases that are more complex than the double-strings set, is proposed to calculate the DTIF and demonstrated through the experimental results. The values of the DTIF on the unbroken insulator string obtained by the experimental models fall between 2.6 and 3.3, which should be a very valuable reference for the design of composite MSI sets. The size of connection fittings is a key factor that influences the DTIF, and the yoke height between the insulator strings and the conductors is the most sensitive parameter. The application of the proposed method to calculate the DTIF can improve the existing design approach to ensure the safety of the tension composite MSI sets, especially for high voltage transmission lines.
      PubDate: April 2022
      Issue No: Vol. 37, No. 2 (2022)
       
  • Multiscale Fusion Simulation of the Influence of Temperature on the
           Partial Discharge Signal of GIS Insulation Void Defects

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      Authors: Hui Song;Zhaoqi Zhang;Jiapeng Tian;Gehao Sheng;Xiuchen Jiang;
      Pages: 1304 - 1314
      Abstract: Gas insulated switchgear (GIS) in service may tolerate large temperature changes, which leads to uncertainty in the evaluation of the partial discharge (PD) signal. To clarify the influence of temperature on the discharge signals of GIS insulation void defects, this paper proposes a multiscale fusion simulation method and used experiments to verify it. This method combines the streamer simulation at the micro level and the circuit simulation model at the macro level, and a more accurate simulation signal of GIS insulation void PDs under the influence of temperature can be obtained. Experiments have also been carried out, and a PDs detection experiment platform that can be set in different temperature environments was built. The discharge signals at different temperatures were obtained follow IEC60270. Finally, by combining analyses of simulation and experimental data, the law of the influence of temperature on the PD signal of GIS insulation voids was summarized, and the mechanism of the influence was analyzed. The results showed that the multiscale fusion simulation method of GIS insulation void PD signals proposed in this paper is consistent with the experimental results, which can provide a reference for the digital twin model of power equipment status.
      PubDate: April 2022
      Issue No: Vol. 37, No. 2 (2022)
       
  • Multi-Objective Optimization Aiming to Minimize the Number of Power
           Quality Monitors and Multiple Fault Estimations in Unbalanced Power
           Distribution Systems

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      Authors: Paulo Estevão Teixeira Martins;Mário Oleskovicz;
      Pages: 1315 - 1323
      Abstract: Utilities are already concerned about power quality monitoring. Several papers proposed strategies to choose the best locations to install power quality monitors, minimizing the investment cost while guaranteeing observability of power quality disturbances, mostly voltage sags. Although several papers studied this problem in power transmission systems, many problems remain unsolved for power distribution systems, such as power quality monitors allocation in unbalanced distribution systems, the impact of distributed generation in allocation methods, and allocation of power quality monitor for fault location. This paper makes contributions in all these three points. It proposes a multi-objective binary integer linear programming model for unbalanced systems, which is still suitable for power transmission systems. Furthermore, we analyze the connection/disconnection of a distributed generator, and our tests showed no need to change allocation regardless of the generator connection status. Finally, the allocation method reduced the multiple estimation problem; therefore, meter-based fault location methods could improve their performance with our allocation.
      PubDate: April 2022
      Issue No: Vol. 37, No. 2 (2022)
       
  • A Health-Oriented Power Control Strategy of Direct Drive Wind Turbine

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      Authors: Yongan Chen;Longjun Wang;Shenquan Liu;Gang Wang;
      Pages: 1324 - 1335
      Abstract: Offshore wind power has great development potential, of which operation and maintenance costs account for a large proportion in the full lifecycle cost. Power output control strategy plays a key role in wind turbine generator system (WTGS). Traditional control strategies, such as maximum power point tracking and unity power factor, which only uses current local information for decision-making, are not the optimal control method when considering the component fatigue. For the reason, this paper proposes a health-oriented power control strategy, which transforms control problem into an equivalent solution to an economic revenue model. The model aimed to maximize the economic revenue of the full lifecycle, and employed physics-of-failure methodology to quantify the remaining useful life, involving detailed mission profiles. Further, a receding horizon predictive controller is designed to flatten the junction temperature fluctuation and extend converter lifespan, for engineering application. A 1.2 MW WTGS is utilized as a benchmark to verify the proposed strategy performance, and the numerical results reveal the mechanism of the optimized control strategies for alleviating the fatigue and aging of the converters.
      PubDate: April 2022
      Issue No: Vol. 37, No. 2 (2022)
       
  • Stabilizing Condition of Grid-Connected VSC as Affected by Phase Locked
           Loop (PLL)

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      Authors: Yujun Li;Zhengchun Du;
      Pages: 1336 - 1339
      Abstract: The small signal stability of the system that one single VSC is connected to an infinite source via the line is investigated in this letter. An analytical stabilizing condition for such system is derived based on the linearized model. It builds up the relationship between controller parameters, electrical distance, and system operating points for ensuring system stability. It is founded that both large and small proportional gains of PLL may lead to the system instability. Moreover, the system is unstable once the integral gain of PLL exceeds one critical value.
      PubDate: April 2022
      Issue No: Vol. 37, No. 2 (2022)
       
  • Hybrid Open Points: An Efficient Tool for Increasing Network Capacity in
           Distribution Systems

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      Authors: Matthew Deakin;Ilias Sarantakos;David M. Greenwood;Janusz Bialek;Phil C. Taylor;Wenlong Ming;Charalampos Patsios;
      Pages: 1340 - 1343
      Abstract: This letter introduces the Hybrid Open Point (HOP), a device consisting of an electromechanical switch connected in parallel with a power converter, for the purpose of providing additional network capacity in interconnected distribution systems. The HOP switch is used for bulk power transfer at low-cost, whilst the HOP converter provides targeted power transfer when the HOP switch is open. The device can replace either a Normally Open Point (Type 1 HOP) or a Normally Closed Point (Type 2 HOP). Simple interconnection and teed interconnection configurations are studied considering fault level and radiality constraints, with realistic use-cases identified for both HOP types. The HOP is shown to provide secure network capacity more cost-effectively than the classical Soft Open Point.
      PubDate: April 2022
      Issue No: Vol. 37, No. 2 (2022)
       
  • Data-Driven Optimization Framework for Voltage Regulation in Distribution
           Systems

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      Authors: Tianqi Hong;Yichen Zhang;
      Pages: 1344 - 1347
      Abstract: This letter proposes a data-driven optimization framework for voltage regulation problems to address the challenge of model inaccuracy and parameter varying. To achieve online voltage optimization, the recursive kernel regression and interior point methods are integrated. The IEEE 123-Bus system and EPRI Ckt5 feeder are selected to validate the effectiveness of the proposed data-driven optimization framework. The proposed method is also compared with a linear function based method.
      PubDate: April 2022
      Issue No: Vol. 37, No. 2 (2022)
       
  • Further Results on Newton-Raphson Method in Feasible Power-Flow for DC
           Distribution Networks

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      Authors: Zhangjie Liu;Ruisong Liu;Xin Zhang;Mei Su;Yao Sun;Hua Han;Peng Wang;
      Pages: 1348 - 1351
      Abstract: This letter analyzes the convergence of the Newton-Raphson method for the power-flow equation of a DC distribution network with constant power loads (CPLs). Specifically, this letter aims to: 1) determine the sufficient and necessary solvability condition of the power-flow equation; 2) derive the convergence condition of the Newton-Raphson (NR) method. For the first issue, the necessary and sufficient solvability condition for the power-flow equation is derived. On this basis, the convergence of the NR method is analyzed, and the convergence condition about the initial iterative value is obtained. Moreover, it is proved that the NR method under the proposed convergence condition is convergent as long as the power-flow equation is solvable. Finally, case studies verify the correctness of the presented theoretical analysis.
      PubDate: April 2022
      Issue No: Vol. 37, No. 2 (2022)
       
  • Introducing the IEEE PES Resource Center

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      Pages: 1352 - 1352
      Abstract: Presents information on the IEEE PES Resource Center.
      PubDate: April 2022
      Issue No: Vol. 37, No. 2 (2022)
       
 
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