The Experts below are selected from a list of 243 Experts worldwide ranked by ideXlab platform

J M Baptista - One of the best experts on this subject based on the ideXlab platform.

  • optimal Cable Design of wind farms the infrastructure and losses cost minimization case
    IEEE Transactions on Power Systems, 2016
    Co-Authors: Adelaide Cerveira, Amaro De Sousa, E Solteiro J Pires, J M Baptista
    Abstract:

    Wind power is the source of electrical energy that has grown more over the last years, with annual rate in installed capacity around 20%. Therefore, it is important to optimize the production efficiency of wind farms. In a wind farm, the electrical energy is collected at a central substation from different wind turbines placed nearby. This paper addresses the optimal Design of the Cable network interconnecting the turbines to the substation aiming to minimize not only the infrastructure cost but also the cost of the energy losses in the Cables. Although this problem is nonlinear, different integer linear programming models are proposed considering the wind farm technical constraints. The models are applied to three real cases Portuguese wind farms. The computational results show that the proposed models are able to compute the optimal solutions for all cases.

Adelaide Cerveira - One of the best experts on this subject based on the ideXlab platform.

  • optimal Cable Design of wind farms the infrastructure and losses cost minimization case
    IEEE Transactions on Power Systems, 2016
    Co-Authors: Adelaide Cerveira, Amaro De Sousa, E Solteiro J Pires, J M Baptista
    Abstract:

    Wind power is the source of electrical energy that has grown more over the last years, with annual rate in installed capacity around 20%. Therefore, it is important to optimize the production efficiency of wind farms. In a wind farm, the electrical energy is collected at a central substation from different wind turbines placed nearby. This paper addresses the optimal Design of the Cable network interconnecting the turbines to the substation aiming to minimize not only the infrastructure cost but also the cost of the energy losses in the Cables. Although this problem is nonlinear, different integer linear programming models are proposed considering the wind farm technical constraints. The models are applied to three real cases Portuguese wind farms. The computational results show that the proposed models are able to compute the optimal solutions for all cases.

Zhang Kai - One of the best experts on this subject based on the ideXlab platform.

  • Guy Cable Design of Vertical Axis Wind Turbine
    Journal of Chongqing Institute of Technology, 2007
    Co-Authors: Zhang Kai
    Abstract:

    The aim of guy Cable Design of vertical axis wind turbine is to supply sufficient stiffness on the top of the rotor of vertical axis wind turbine and enough strength for guy Cable.The stiffness on the top of rotor of wind turbine and the vibration characteristics of the guy Cable are affected synthetically by the section dimension,the sag、the mass and the pre-tension of the guy Cable. To determine the key parameters of the guy Cable Design of wind turbine,a cycling method combining with finite element method is used and its feasibility is demonstrated with an example.

P H F Morshuis - One of the best experts on this subject based on the ideXlab platform.

  • feature article polymeric hvdc Cable Design and space charge accumulation part 2 insulation interfaces
    IEEE Electrical Insulation Magazine, 2008
    Co-Authors: S Deipino, D Fabiani, G C Montanari, Christian Laurent, G Teyssedre, P H F Morshuis, R Bodega, L A Dissado
    Abstract:

    The electric field distribution of Cable insulation systems under HVDC can be affected significantly at interfaces due to space charge build-up. In this article, the second part of a three-article series, face and space charge accumulation are analyzed first in terms of macroscopic physics, then through approximate mathematical models that will be used to fit experimental data obtained for model Cables having two insulation layers and constituting cylindrical interfaces.

  • polymeric hvdc Cable Design and space charge accumulation part 2 insulation interfaces
    2008
    Co-Authors: S Delpino, D Fabiani, G C Montanari, Christian Laurent, G Teyssedre, P H F Morshuis
    Abstract:

    Introduction onhomogeneous electrical insulating materials and interfaces between different materials are frequently encountered in electric insulation systems. On one hand there are composite insulating materials obtained by a host material containing micro and/or nano fillers, which have been widely investigated with the aim of improving the properties of the base material. The presence of micro/nano scale interfaces may affect the physical and electrical properties of the composite material, improving or worsening them with respect to the base material. This depends on the nature and dispersion of micro/nano filler inside the matrix. On the other hand, interfaces can be found on a macro-scale in several HV insulation systems, e.g., in Cables. In particular, interfaces between Cable insulation and semiconductive layers and/or between different insulating materials in Cable accessories (e.g., XLPE and EPR used for Cable joints and/or terminations) are very common in transmission and distribution networks. It must be remembered that interfaces are often claimed to be critical within the complete insulation system, affecting electrical, mechanical, and thermal properties. Indeed, the effects of electro-thermal and mechanical stresses can be enhanced in the presence of interfaces that may, thus, become the weakest points of the insulation system, both in AC and DC [1]. Interfaces can act as a trigger for partial discharges (PD) when the contact between surfaces is not well made, and such activity should be strictly avoided for Cable and accessories because organic insulation (e.g., XLPE and EPR) might not be able to withstand PD activity, even for short times [2], [3]. It is likely that PD activity will be a second-order problem under DC due to the smaller repetition rate with respect to AC. However, under a DC field, space charge may accumulate in the insulation bulk, especially if interfaces are present [4]–[8]. The latter, in fact, can behave as favored sites for charge build up, particularly for low-mobility materials (e.g., polymeric insulation). Space charge can modify the electric field in such a way that the actual field in the insulation can differ significantly from the geometric field, thus causing accelerated S. Delpino, D. Fabiani, and G. C Montanari University of Bologna, Italy C. Laurent and G. Teyssedre Universite Paul Sabatier, Toulouse, France P. H. F. Morshuis TU Delft, The Netherlands R. Bodega Prysmian Cables & Systems, The Netherlands L. A. Dissado University of Leicester, UK

  • polymeric hvdc Cable Design and space charge accumulation part 1 insulation semicon interface
    IEEE Electrical Insulation Magazine, 2007
    Co-Authors: D Fabiani, G C Montanari, Christian Laurent, G Teyssedre, P H F Morshuis, R Bodega, L A Dissado, Alfred Campus, Ulf Nilsson
    Abstract:

    From theory and experiments, it can be deduced that materials for DC applications should not accumulate a large amount of space charge if accelerated degradation of the insulation system is to be avoided. Therefore, the characterization of DC insulation must take into account the evaluation of space charge accumulation. This cannot be done exhaustively without taking a system approach considering both the semiconductive material and the insulation, in particular, the properties of the semicon/insulation interface. The latter interface, in fact, plays a major role in space charge injection/accumulation in the insulation bulk. Having analyzed different semiconductive and insulating materials candidate for HVDC Cable applications, the best solution to be exploited for HVDC Cable Design would be the combination showing a high threshold for space charge accumulation, a small rate of charge accumulation as a function of electric field and a small activation energy, i.e., a space charge amount less dependent on temperature. Therefore, space charge measurements will provide important information to Cable material manufacturers with the aim of tailoring insulation and semicon specifically for HVDC application and, thus, improving the reliability of polymeric Cables.

  • Polymeric HVDC Cable Design and Space Charge Accumulation. Part 1: Insulation/Semicon Interface
    IEEE Electrical Insulation Magazine, 2007
    Co-Authors: D Fabiani, G C Montanari, Christian Laurent, G Teyssedre, P H F Morshuis, R Bodega, L A Dissado, Alfred Campus, Ulf Nilsson
    Abstract:

    From theory and experiments, it can be deduced that materials for DC applications should not accumulate a large amount of space charge if accelerated degradation of the insulation system is to be avoided. Therefore, the characterization of DC insulation must take into account the evaluation of space charge accumulation. This cannot be done exhaustively without taking a system approach considering both the semiconductive material and the insulation, in particular, the properties of the semicon/insulation interface. The latter interface, in fact, plays a major role in space charge injection/accumulation in the insulation bulk. Having analyzed different semiconductive and insulating materials candidate for HVDC Cable applications, the best solution to be exploited for HVDC Cable Design would be the combination showing a high threshold for space charge accumulation, a small rate of charge accumulation as a function of electric field and a small activation energy, i.e., a space charge amount less dependent on temperature. Therefore, space charge measurements will provide important information to Cable material manufacturers with the aim of tailoring insulation and semicon specifically for HVDC application and, thus, improving the reliability of polymeric Cables.

D Fabiani - One of the best experts on this subject based on the ideXlab platform.

  • feature article polymeric hvdc Cable Design and space charge accumulation part 2 insulation interfaces
    IEEE Electrical Insulation Magazine, 2008
    Co-Authors: S Deipino, D Fabiani, G C Montanari, Christian Laurent, G Teyssedre, P H F Morshuis, R Bodega, L A Dissado
    Abstract:

    The electric field distribution of Cable insulation systems under HVDC can be affected significantly at interfaces due to space charge build-up. In this article, the second part of a three-article series, face and space charge accumulation are analyzed first in terms of macroscopic physics, then through approximate mathematical models that will be used to fit experimental data obtained for model Cables having two insulation layers and constituting cylindrical interfaces.

  • polymeric hvdc Cable Design and space charge accumulation part 2 insulation interfaces
    2008
    Co-Authors: S Delpino, D Fabiani, G C Montanari, Christian Laurent, G Teyssedre, P H F Morshuis
    Abstract:

    Introduction onhomogeneous electrical insulating materials and interfaces between different materials are frequently encountered in electric insulation systems. On one hand there are composite insulating materials obtained by a host material containing micro and/or nano fillers, which have been widely investigated with the aim of improving the properties of the base material. The presence of micro/nano scale interfaces may affect the physical and electrical properties of the composite material, improving or worsening them with respect to the base material. This depends on the nature and dispersion of micro/nano filler inside the matrix. On the other hand, interfaces can be found on a macro-scale in several HV insulation systems, e.g., in Cables. In particular, interfaces between Cable insulation and semiconductive layers and/or between different insulating materials in Cable accessories (e.g., XLPE and EPR used for Cable joints and/or terminations) are very common in transmission and distribution networks. It must be remembered that interfaces are often claimed to be critical within the complete insulation system, affecting electrical, mechanical, and thermal properties. Indeed, the effects of electro-thermal and mechanical stresses can be enhanced in the presence of interfaces that may, thus, become the weakest points of the insulation system, both in AC and DC [1]. Interfaces can act as a trigger for partial discharges (PD) when the contact between surfaces is not well made, and such activity should be strictly avoided for Cable and accessories because organic insulation (e.g., XLPE and EPR) might not be able to withstand PD activity, even for short times [2], [3]. It is likely that PD activity will be a second-order problem under DC due to the smaller repetition rate with respect to AC. However, under a DC field, space charge may accumulate in the insulation bulk, especially if interfaces are present [4]–[8]. The latter, in fact, can behave as favored sites for charge build up, particularly for low-mobility materials (e.g., polymeric insulation). Space charge can modify the electric field in such a way that the actual field in the insulation can differ significantly from the geometric field, thus causing accelerated S. Delpino, D. Fabiani, and G. C Montanari University of Bologna, Italy C. Laurent and G. Teyssedre Universite Paul Sabatier, Toulouse, France P. H. F. Morshuis TU Delft, The Netherlands R. Bodega Prysmian Cables & Systems, The Netherlands L. A. Dissado University of Leicester, UK

  • polymeric hvdc Cable Design and space charge accumulation part 1 insulation semicon interface
    IEEE Electrical Insulation Magazine, 2007
    Co-Authors: D Fabiani, G C Montanari, Christian Laurent, G Teyssedre, P H F Morshuis, R Bodega, L A Dissado, Alfred Campus, Ulf Nilsson
    Abstract:

    From theory and experiments, it can be deduced that materials for DC applications should not accumulate a large amount of space charge if accelerated degradation of the insulation system is to be avoided. Therefore, the characterization of DC insulation must take into account the evaluation of space charge accumulation. This cannot be done exhaustively without taking a system approach considering both the semiconductive material and the insulation, in particular, the properties of the semicon/insulation interface. The latter interface, in fact, plays a major role in space charge injection/accumulation in the insulation bulk. Having analyzed different semiconductive and insulating materials candidate for HVDC Cable applications, the best solution to be exploited for HVDC Cable Design would be the combination showing a high threshold for space charge accumulation, a small rate of charge accumulation as a function of electric field and a small activation energy, i.e., a space charge amount less dependent on temperature. Therefore, space charge measurements will provide important information to Cable material manufacturers with the aim of tailoring insulation and semicon specifically for HVDC application and, thus, improving the reliability of polymeric Cables.

  • Polymeric HVDC Cable Design and Space Charge Accumulation. Part 1: Insulation/Semicon Interface
    IEEE Electrical Insulation Magazine, 2007
    Co-Authors: D Fabiani, G C Montanari, Christian Laurent, G Teyssedre, P H F Morshuis, R Bodega, L A Dissado, Alfred Campus, Ulf Nilsson
    Abstract:

    From theory and experiments, it can be deduced that materials for DC applications should not accumulate a large amount of space charge if accelerated degradation of the insulation system is to be avoided. Therefore, the characterization of DC insulation must take into account the evaluation of space charge accumulation. This cannot be done exhaustively without taking a system approach considering both the semiconductive material and the insulation, in particular, the properties of the semicon/insulation interface. The latter interface, in fact, plays a major role in space charge injection/accumulation in the insulation bulk. Having analyzed different semiconductive and insulating materials candidate for HVDC Cable applications, the best solution to be exploited for HVDC Cable Design would be the combination showing a high threshold for space charge accumulation, a small rate of charge accumulation as a function of electric field and a small activation energy, i.e., a space charge amount less dependent on temperature. Therefore, space charge measurements will provide important information to Cable material manufacturers with the aim of tailoring insulation and semicon specifically for HVDC application and, thus, improving the reliability of polymeric Cables.