The Experts below are selected from a list of 15303 Experts worldwide ranked by ideXlab platform
Felipe V Lopes - One of the best experts on this subject based on the ideXlab platform.
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traveling wave based transmission line Earth Fault distance protection
IEEE Transactions on Power Delivery, 2020Co-Authors: R L S Franca, Francisco C Silva, Tiago R Honorato, Joao Paulo G Ribeiro, F B Costa, Felipe V Lopes, Kai StrunzAbstract:This paper proposes a one-terminal traveling wave (TW)-based transmission line Earth Fault distance protection function. It only needs the detection of the first incident modal Earth Fault-induced TWs, so that, the challenging detection of wavefronts reflected from the Fault point is not required. Both the sampling frequency effect and inaccuracies on the wave propagation velocity are considered in order to define the distance protection zone. Simulated Fault records were played back in an actual relay, allowing the comparison between a commercially existing time-domain distance protection element and the proposed one. The proposed function is more accurate and significantly reduces transmission line
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settings free traveling wave based Earth Fault location using unsynchronized two terminal data
Power and Energy Society General Meeting, 2018Co-Authors: Felipe V LopesAbstract:This paper presents a two-terminal traveling-wave (TW)-based Earth Fault-location algorithm. It works using unsynchronized data and does not require information about the line parameters. Evaluated signals are decoupled into aerial and ground modes and, then, only the incident TWs of each mode are detected at the line ends. Earth Fault case studies are carried out to attest the proposed algorithm feasibility, comparing its performance with those of one- and two-terminal approaches reported in the literature. Obtained results reveal that the proposed algorithm is straightforward and quite reliable.
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Settings-Free Traveling-Wave-Based Earth Fault Location Using Unsynchronized Two-Terminal Data
IEEE Transactions on Power Delivery, 2016Co-Authors: Felipe V LopesAbstract:This letter presents a two-terminal traveling-wave (TW)-based Earth Fault-location algorithm. It works using unsynchronized data and does not require information about the line parameters. Evaluated signals are decoupled into aerial and ground modes and, then, only the incident TWs of each mode are detected at the line ends. Earth Fault case studies are carried out to attest the proposed algorithm feasibility, comparing its performance with those of one- and two-terminal approaches reported in the literature. Obtained results reveal that the proposed algorithm is straightforward and quite reliable.
Matti Lehtonen - One of the best experts on this subject based on the ideXlab platform.
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A novel 4-limb Earth Fault compensation reactor for distribution network
International Transactions on Electrical Energy Systems, 2017Co-Authors: Jyrki Penttonen, Matti Lehtonen, Shafiq MuhammadAbstract:Summary This paper presents a novel Earth Fault compensation solution, which presents high positive sequence impedance and magnetically controllable zero sequence impedance. A 4-limb reactor is introduced to compensate Earth Fault currents in three-phase power distribution networks without the need of neutral point in substation transformer or separate Earthing transformer. This results in considerably lower costs in implementing Earth Fault current compensation with much faster operation, making it possible to tune for 100% compensation during Fault thus improving the probability of arc suppression. The presented reactor is analyzed analytically, and its performance is validated by simulations. The presented solution can significantly improve the reliability of the supply network.
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optimal distribution network automation considering Earth Fault events
IEEE Transactions on Smart Grid, 2015Co-Authors: Osmo Siirto, Matti Lehtonen, Amir Safdarian, Mahmud FotuhifiruzabadAbstract:In the past decade, distribution network operators have been broadly engrossed toward automated distribution networks. The operators acknowledge network automation as an efficient investment toward a better service reliability. This paper aims to provide a new long-term cost/benefit analysis for an optimal level of distribution network automation. In the analysis, reduction in customer outage cost is considered as the benefit of implementing automation systems with capital investment, and annual operation and maintenance costs. In the Finnish regulation model, there is a special incentive based on customer outage cost reduction. As the main contribution of this paper, the impact of Earth Fault events and their required time-consuming Fault management process is taken into account within the calculation of the benefit of automation systems. The solution of the analysis consists of the optimal number and location of remote-controlled sectionalizing switches, which are building blocks of automation systems. The problem is formulated in a mixed-integer linear programming format that can be effectively solved by commercially available solvers. The effectiveness of the proposed algorithm is demonstrated by applying it to the Helsinki distribution network. The results show that neglecting the impact of Earth Fault events can lead to suboptimal solutions.
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Decentralized Earth Fault selectivity using transient front slopes for unEarthed MV networks
International Journal of Electrical Power & Energy Systems, 2014Co-Authors: Nagy I. Elkalashy, Matti LehtonenAbstract:In this paper, a transient-based selectivity function is introduced for identifying the Faulty section due to Earth Faults. The proposed selectivity procedure enhances the Earth Fault management in unEarthed/compensated MV networks using decentralized control. The Faulty section is discriminated by evaluating relative polarities, at each section terminals of front slopes, created by the Earth Fault occurrence. The Fault surge slopes are extracted by differentiating the residual current waveforms. A threshold value is evaluated to localize the polarity measuring. The outline of integrating the proposed selectivity function is discussed with the decentralized control.
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Neutral point treatment and Earth Fault suppression
2012 Electric Power Quality and Supply Reliability, 2012Co-Authors: Osmo Siirto, Mika Loukkalahti, Markku Hyvärinen, Pirjo Heine, Matti LehtonenAbstract:Earth Fault management in medium voltage networks involves assessing of customer interruptions, challenges in Fault clearing processes and safety issues. The major advantage by allowing sustained Earth Faults is the avoidance of customer interruptions. However, the network operation with sustained Earth Faults does not only include welfare. The paper will generally discuss the advantages and disadvantages of operating the network with sustained Earth Faults. In addition, in the paper, the Helsinki medium voltage network and the developments in neutral point treatment and network operation during Earth Faults will be outlined. The paper presents the Earth Fault analysis in the Helsinki 10 kV network and compares the results to a reference analysis. Based on the analysis, the paper presents the possibilities and limitations of a sustained operation with Earth Faults. The paper also presents the strategy steps of managing sustained Earth Faults as well in the 10 kV and 20 kV areas and the required long term development steps.
Shen Quanrong - One of the best experts on this subject based on the ideXlab platform.
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Discussion on Location Function of Detecting Generator Rotor Earth Fault
Automation of electric power systems, 2011Co-Authors: Chen Jun, Tan Tao, Wang Guang, Zhang Qixue, Yan Wei, Shen QuanrongAbstract:The principle of rotor Earth Fault location detecting method is introduced,and theoretical analysis indicates that its precision depends on the computing precision of relative Earth Fault location.Three factors affecting the precision are analyzed for the rotor Earth Fault location detecting method.Unstable Earth Fault and variable brush touching resistance can result in inaccuracy,and single phase Earth Fault at low voltage side of excitation transformer may cause misjudge.The research results demonstrate that the generator rotor Earth Fault location detecting method is only for qualitative reference of Earth Fault searching.It is needless to configure a special generator rotor Earth Fault location detection device.
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Study on Issues of Generator Rotor Earth Fault Protection
Automation of electric power systems, 2008Co-Authors: Shen QuanrongAbstract:This paper analyzes the influences of shaft voltage absorbing circuit and brush touching resistance on the performance of generator rotor Earth Fault protection. Some countermeasures and advices are presented. Prolonging period of electric switches and injected square voltage is suggested to eliminate the influence of shaft voltage. It is necessary for rotor Earth Fault protection to keep good-touching of grounding brush and rotor shaft. Rotor Earth Fault protection configuration of revolving excitation generator is investigated subsequently, and periodical detecting mode is commended.
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Generator Stator and Rotor Earth Fault Protection Scheme of Ultra-supercritical Generating Unit
Automation of electric power systems, 2008Co-Authors: Shen QuanrongAbstract:This paper analyzes the shortage of conventional generator stator and rotor Earth Fault protection applied to ultra-supercritical generating unit.A novel stator and rotor Earth Fault protection scheme is proposed subsequently,and voltage injection type stator and rotor Earth Fault protection are commended,which are immune to the operating condition of generator.
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field application and analysis of the stator Earth Fault protection with voltage injection for large sized generator
Automation of electric power systems, 2007Co-Authors: Shen QuanrongAbstract:More and more large-sized generators are installed 100% stator Earth Fault protection with low-frequency alternating-voltage injection.The field adjustment methods of the voltage injection scheme against the stator Earth Fault protection are summarized and the experimental results are given.The equipment measuring accuracy(relative error is not greater than ±5%)of the Earth Fault resistors is verified by the experimental results.Moreover,some suggestions are given by analyzing a two-point Earth Fault in potential transformers circuit,which can cause stator Earth Fault protection warning.
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study on stator Earth Fault protection of generator connected as expanding unit
Automation of electric power systems, 2007Co-Authors: Shen QuanrongAbstract:A novel selective stator Earth Fault protection based on zero-sequence direction element is proposed, which can overcome the shortage of stator Earth Fault protection applied to generator connected as expanding unit. In the proposed algorithm, the zero-sequence direction criterion is calculated with zero-sequence current of generator terminal, the secondary current of neutral Earthing transformer and zero-sequence voltage of generator, and its operating border can be set flexibly. The presented criterion can differentiate between a network Earth Fault and a generator stator Earth Fault exactly, which has been realized in digital generator protection. Experiment results show its validity and reliability.
Stanislaw Czapp - One of the best experts on this subject based on the ideXlab platform.
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Improving sensitivity of residual current transformers to high frequency Earth Fault currents
Archives of Electrical Engineering, 2017Co-Authors: Stanislaw Czapp, Krzysztof Dobrzyński, Jacek Klucznik, Zbigniew Lubosny, Robert KowalakAbstract:For protection against electric shock in low voltage systems residual current devices are commonly used. However, their proper operation can be interfered when high frequency Earth Fault current occurs. Serious hazard of electrocution exists then. In order to detect such a current, it is necessary to modify parameters of residual current devices, especially the operating point of their current transformer. The authors proposed the modification in the structure of residual current devices. This modification improves sensitivity of residual current devices when high frequency Earth Fault current occurs. The test of the modified residual current device proved that the authors’ proposition is appropriate.
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The effect of the motor filters on Earth Fault current waveform in circuits with variable speed drives
International School on Nonsinusoidal Currents and Compensation 2013 (ISNCC 2013), 2013Co-Authors: Stanislaw Czapp, Jaroslaw GuzinskiAbstract:In circuits with variable speed drives distorted Earth Fault current flows. Earth Fault current distortion influences the threshold of ventricular fibrillation. This paper presents Earth Fault current distortion in circuits with variable speed drives when motor filter is used. Two types of motor filter are analyzed. For every type of filter the effect of Earth Fault current distortion on ventricular fibrillation is evaluated.
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The effect of the motor filters on Earth Fault current waveform in circuits with variable speed drives
International School on Nonsinusoidal Currents and Compensation 2013 (ISNCC 2013), 2013Co-Authors: Stanislaw Czapp, Jaroslaw GuzinskiAbstract:In circuits with variable speed drives distorted Earth Fault current flows. Earth Fault current distortion influences the threshold of ventricular fibrillation. This paper presents Earth Fault current distortion in circuits with variable speed drives when motor filter is used. Two types of motor filter are analyzed. For every type of filter the effect of Earth Fault current distortion on ventricular fibrillation is evaluated.
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The Impact of DC Earth Fault Current Shape on Tripping of Residual Current Devices
Elektronika Ir Elektrotechnika, 2008Co-Authors: Stanislaw CzappAbstract:Nowadays the manufacturers of electrical appliances introduce electronic components to improve the performance of their products. Many industrial and domestic devices comprise different types of convertors generating DC Earth Fault current. The shape of that current influences the RCD tripping. In this paper the impact of DC Earth Fault current shape on RCD residual operating current is presented and results of laboratory tests are discussed. They prove proper tripping of many RCDs even when the DC component in Earth Fault current is significantly greater than that required in standards. Results of the DC Earth Fault current transformation by the Ferranti current transformers are also presented. Ill. 8, tabl. 2, bibl. 4 (in English; summaries in English, Russian and Lithuanian).
Minkley Warick - One of the best experts on this subject based on the ideXlab platform.
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Analysis of restricted Earth Fault relay application within a shunt capacitor bank design impacting on protection stability
Faculty of Engineering the Built Environment and Information Technology, 2013Co-Authors: Minkley WarickAbstract:This research is aimed at analyzing the performance of the restricted Earth Fault relay used on a 400kV capacitor bank scheme used on the Eskom Transmission network. After the commissioning of two Capacitor Banks using the above mentioned scheme design the plant was energized. As a result of the energization the Shunt Capacitor Bank (SCB) then experienced spurious trips. The cause of the trips was found to be the operation of the restricted Earth Fault relay. In this research project, restricted Earth Fault protection on SCBs in the Eskom Transmission environment will be the area of interest. The proposed research will analyze the current SCB protection scheme in service specifically looking at the restricted Earth Fault circuit design and relay performance. An equivalent model of the SCB from primary plant perspective based on theory will be derived. Recording and analyzing of Comtrade transient waveforms respectively, when the bank is nergized, will be done in order to provide a reference base to work from. Manual alculations of various parameters from the derived model including transient inrush currents and Fault currents will be performed to access applicable scheme parameters. Further calculations will include the voltage setting for the restricted Earth Fault relay. As a result of the analysis a recommendation will be made on a viable solution or a revised design will be put forward, based on the results, to improve the scheme’s performance. The protection scheme is used on the two 400kV 100MVAR capacitor banks 11 and 12 at Hydra Substation
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Analysis of restricted Earth Fault relay application within a shunt capacitor bank design impacting on protection stability
Nelson Mandela Metropolitan University, 2013Co-Authors: Minkley WarickAbstract:This research is aimed at analyzing the performance of the restricted Earth Fault relay used on a 400kV capacitor bank scheme used on the Eskom Transmission network. After the commissioning of two Capacitor Banks using the above mentioned scheme design the plant was energized. As a result of the energization the Shunt Capacitor Bank (SCB) then experienced spurious trips. The cause of the trips was found to be the operation of the restricted Earth Fault relay. In this research project, restricted Earth Fault protection on SCBs in the Eskom Transmission environment will be the area of interest. The proposed research will analyze the current SCB protection scheme in service specifically looking at the restricted Earth Fault circuit design and relay performance. An equivalent model of the SCB from primary plant perspective based on theory will be derived. Recording and analyzing of Comtrade transient waveforms respectively, when the bank is energized, will be done in order to provide a reference base to work from. Manual calculations of various parameters from the derived model including transient inrush currents and Fault currents will be performed to access applicable scheme parameters. Further calculations will include the voltage setting for the restricted Earth Fault relay. As a result of the analysis a recommendation will be made on a viable solution or a revised design will be put forward, based on the results, to improve the scheme’s performance. The protection scheme is used on the two 400kV 100MVAR capacitor banks 11 and 12 at Hydra Substatio
