The Experts below are selected from a list of 303 Experts worldwide ranked by ideXlab platform
N V Korovkin - One of the best experts on this subject based on the ideXlab platform.
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a review of current issues in Lightning Protection of new generation wind turbine blades
IEEE Transactions on Industrial Electronics, 2008Co-Authors: Farhad Rachidi, Marcos Rubinstein, Joan Montanya, J L Bermudez, Rodriguez R Sola, Gloria Sola, N V KorovkinAbstract:The salient issues related to Lightning Protection of long wind-turbine blades are discussed in this paper. We show that the Lightning Protection of modern wind turbines presents a number of new challenges due to the geometrical, electrical, and mechanical particularities of the turbines. The risk assessment for the Lightning-Protection-System design is solely based today on downward flashes. We show in this paper that the majority of the strikes to modern turbines are expected to be upward Lightning. Neglecting upward flashes, as implicitly done by the International Electrotechnical Commission, might result in an important underestimation of the actual number of strikes to a tall wind turbine. In addition, we show that the rotation of the blades may have a considerable influence on the number of strikes to modern wind turbines as these may be triggering their own Lightning. Because wind turbines are tall structures, the Lightning currents that are injected by return strokes into the turbines will be affected by reflections at the top, bottom, and junction of the blades with the static base of the turbine. This is of capital importance when calculating the Protection of internal circuitry that may be affected by magnetically induced electromotive forces that depend directly on the characteristics of the current in the turbine. The presence of carbon-reinforced plastics (CRP) in the blades introduces a new set of problems to be dealt with in the design of the turbines' Lightning Protection System. One problem is the mechanical stress resulting from the energy dissipation in CRP laminates due to the circulation of eddy currents. We evaluate in this paper the dissipated energy and propose recommendations as to the number of down conductors and their orientation with respect to the CRP laminates so that the dissipated energy is minimized. It is also emphasized that the high static fields under thunderclouds might have an influence on the moving carbon-fiber parts. This issue needs to be addressed by Lightning Protection researchers and engineers. Representative full-scale blade tests are still complex because Lightning currents from an impulse current generator are conditioned to the electrical characteristics of the element under test and return paths. It is therefore desirable to complement laboratory tests with theoretical and computer modeling for the estimation of fields, currents, and voltages within the blades.
Farhad Rachidi - One of the best experts on this subject based on the ideXlab platform.
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a review of current issues in Lightning Protection of new generation wind turbine blades
IEEE Transactions on Industrial Electronics, 2008Co-Authors: Farhad Rachidi, Marcos Rubinstein, Joan Montanya, J L Bermudez, Rodriguez R Sola, Gloria Sola, N V KorovkinAbstract:The salient issues related to Lightning Protection of long wind-turbine blades are discussed in this paper. We show that the Lightning Protection of modern wind turbines presents a number of new challenges due to the geometrical, electrical, and mechanical particularities of the turbines. The risk assessment for the Lightning-Protection-System design is solely based today on downward flashes. We show in this paper that the majority of the strikes to modern turbines are expected to be upward Lightning. Neglecting upward flashes, as implicitly done by the International Electrotechnical Commission, might result in an important underestimation of the actual number of strikes to a tall wind turbine. In addition, we show that the rotation of the blades may have a considerable influence on the number of strikes to modern wind turbines as these may be triggering their own Lightning. Because wind turbines are tall structures, the Lightning currents that are injected by return strokes into the turbines will be affected by reflections at the top, bottom, and junction of the blades with the static base of the turbine. This is of capital importance when calculating the Protection of internal circuitry that may be affected by magnetically induced electromotive forces that depend directly on the characteristics of the current in the turbine. The presence of carbon-reinforced plastics (CRP) in the blades introduces a new set of problems to be dealt with in the design of the turbines' Lightning Protection System. One problem is the mechanical stress resulting from the energy dissipation in CRP laminates due to the circulation of eddy currents. We evaluate in this paper the dissipated energy and propose recommendations as to the number of down conductors and their orientation with respect to the CRP laminates so that the dissipated energy is minimized. It is also emphasized that the high static fields under thunderclouds might have an influence on the moving carbon-fiber parts. This issue needs to be addressed by Lightning Protection researchers and engineers. Representative full-scale blade tests are still complex because Lightning currents from an impulse current generator are conditioned to the electrical characteristics of the element under test and return paths. It is therefore desirable to complement laboratory tests with theoretical and computer modeling for the estimation of fields, currents, and voltages within the blades.
W H Siew - One of the best experts on this subject based on the ideXlab platform.
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experimental study on Lightning attachment manner to wind turbine blades with Lightning Protection System
IEEE Transactions on Plasma Science, 2019Co-Authors: Zixi Guo, Zhiyang Fang, Chu Che, W H SiewAbstract:Different types of Lightning Protection Systems (LPSs) have been developed for wind turbines to protect the blades from Lightning strikes. However, severe damages caused by Lightning strikes still happen frequently, which creates huge costs. Experiments using a 5-m blade specimen with tip receptors from 1.5-MW wind turbine blades under 3-m air gap were conducted to investigate the Lightning attachment manner to the wind turbine blade with LPS in different situations. Factors including the polarity of the Lightning strikes, the orientation of the blade, and the lateral distances (LDs) between the wind turbine blade and the Lightning downward leader were taken into account. It was found that the types of discharge paths under positive and negative Lightning strikes are quite different, and the positive discharges are much more dangerous to wind turbine blade than the negative ones. The LD between the downward leader and the wind turbine blade is a key factor that influences the interception efficiency. Three types of receptor interception failures were discovered. Multiple upward leaders may incept from the blade body as to intercept the downward leader. However, the Protection range of the tip receptor is quite limited, and the connection of the tip receptor and the blade body is the most vulnerable position hit by the Lightning strikes. The results present the useful reference to the optimal design of the wind turbine blade LPS.
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experimental study on interception failure of Lightning Protection System of wind turbine blade
International Conference on Emerging Technologies, 2017Co-Authors: Waqas Arif, Zixin Guo, Muhammad Ali Aizaz, W H SiewAbstract:Wind turbine (WT) blades are equipped with Lightning Protection System (LPS) consisting of receptors and down conductor in order to intercept Lightning strikes. However, severe damages caused by Lightning strikes still happen frequently, which costs huge losses. In this paper, experiments were conducted to study the Lightning interception failure of WT blade LPS, and the results can be useful to improve the optimal design of LPS. Experiments using 5m blade specimen with tip receptor from 1.5MW wind turbine under 3m air gap are conducted to investigate the Lightning interception failure of LPS in different orientations and lateral distances (LDs). Factors such as the polarity of Lightning strikes, the blade orientation of wind turbine and lateral distance between wind turbine and Lightning downward leader were investigated. The lateral distance between downward leader (DL) and wind turbine blade is a key factor which influences the interception efficiency. Three patterns of receptor interception failure are discovered. The Protection area shows asymmetry under different lateral distance. Multi-upward leaders (UL) from WT blade have been observed in the experiment.
John Morales - One of the best experts on this subject based on the ideXlab platform.
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Lightning Protection System design for distribution networks based on System average interruption frequency minimization
Electric Power Systems Research, 2018Co-Authors: Arturo S Bretas, Roberto J Cabral, Roberto Chouhy Leborgne, Gustavo D Ferreira, John MoralesAbstract:Abstract The effects of Lightning are the main cause of interruptions in electrical networks (distribution feeders), imposing a crucial impact on power quality and reliability. An exhaustive review of the state of the art shows that avant-garde solutions have not yet presented explicit mathematical models that relate the interdependence of these two phenomena. This paper presents a novel mixed integer linear programming (MILP) model to be utilized in the design of Lightning Protection Systems (LPS) and which aims at minimizing sustained and momentary interruptions in distribution networks while leveraging investment costs. The proposed model considers a selection of different shielding structures and grounding Systems. The constraints of the optimization model include technical and economic aspects of LPS implementation. A case study considering a real distribution feeder with 81 buses is presented. Test results highlight the generality of the proposed model and illustrate the potential for real-life application. It is worth pointing out that the proposed optimization model is currently used by a distribution utility as a reliability-oriented tool for LPS design.
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multi objective milp model for distribution Systems reliability optimization a Lightning Protection System design approach
International Journal of Electrical Power & Energy Systems, 2018Co-Authors: Arturo S Bretas, Roberto J Cabral, Roberto Chouhy Leborgne, Gustavo D Ferreira, John MoralesAbstract:Abstract Lightning phenomenon is the main cause of power Systems faults. These faults may cause momentary or permanent service interruptions, thus System reliability is inherently interdependent with Lightning phenomenon. A literature review will show that state-of-the-art solutions have yet to present mathematical explicit models for the interdependency of such two phenomena. In this context, this paper presents a multi-objective mixed integer linear programing (MILP) model for distribution Systems reliability optimization while considering Lightning phenomenon interdependency. The presented multi-objective MILP model aims the simultaneous minimization of SAIFI and MAIFIE reliability indices and associated costs. These goals are achieved by optimizing the Lightning Protection System design, which includes selection and allocation of different types of grounding Systems along distribution feeders, while considering simultaneously network characteristics. Validation is done using real-life 81 bus 23 kV distribution network data. Test results highlight the efficiency of the presented model in improving System reliability while reducing associated costs. The ease of implementation of design, formulation of parameters and encouraging test results indicate potential for real-life application. The multi-objective MILP model is currently used by a distribution utility as a reliability-oriented tool.
Roberto J Cabral - One of the best experts on this subject based on the ideXlab platform.
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Lightning Protection System design for distribution networks based on System average interruption frequency minimization
Electric Power Systems Research, 2018Co-Authors: Arturo S Bretas, Roberto J Cabral, Roberto Chouhy Leborgne, Gustavo D Ferreira, John MoralesAbstract:Abstract The effects of Lightning are the main cause of interruptions in electrical networks (distribution feeders), imposing a crucial impact on power quality and reliability. An exhaustive review of the state of the art shows that avant-garde solutions have not yet presented explicit mathematical models that relate the interdependence of these two phenomena. This paper presents a novel mixed integer linear programming (MILP) model to be utilized in the design of Lightning Protection Systems (LPS) and which aims at minimizing sustained and momentary interruptions in distribution networks while leveraging investment costs. The proposed model considers a selection of different shielding structures and grounding Systems. The constraints of the optimization model include technical and economic aspects of LPS implementation. A case study considering a real distribution feeder with 81 buses is presented. Test results highlight the generality of the proposed model and illustrate the potential for real-life application. It is worth pointing out that the proposed optimization model is currently used by a distribution utility as a reliability-oriented tool for LPS design.
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multi objective milp model for distribution Systems reliability optimization a Lightning Protection System design approach
International Journal of Electrical Power & Energy Systems, 2018Co-Authors: Arturo S Bretas, Roberto J Cabral, Roberto Chouhy Leborgne, Gustavo D Ferreira, John MoralesAbstract:Abstract Lightning phenomenon is the main cause of power Systems faults. These faults may cause momentary or permanent service interruptions, thus System reliability is inherently interdependent with Lightning phenomenon. A literature review will show that state-of-the-art solutions have yet to present mathematical explicit models for the interdependency of such two phenomena. In this context, this paper presents a multi-objective mixed integer linear programing (MILP) model for distribution Systems reliability optimization while considering Lightning phenomenon interdependency. The presented multi-objective MILP model aims the simultaneous minimization of SAIFI and MAIFIE reliability indices and associated costs. These goals are achieved by optimizing the Lightning Protection System design, which includes selection and allocation of different types of grounding Systems along distribution feeders, while considering simultaneously network characteristics. Validation is done using real-life 81 bus 23 kV distribution network data. Test results highlight the efficiency of the presented model in improving System reliability while reducing associated costs. The ease of implementation of design, formulation of parameters and encouraging test results indicate potential for real-life application. The multi-objective MILP model is currently used by a distribution utility as a reliability-oriented tool.