The Experts below are selected from a list of 235134 Experts worldwide ranked by ideXlab platform
Pedro Rodriguez - One of the best experts on this subject based on the ideXlab platform.
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Synchronous Frequency Support of Photovoltaic Power Plants with Inertia Emulation
2019 IEEE Energy Conversion Congress and Exposition (ECCE), 2019Co-Authors: Cristian Verdugo, Andres Tarraso, Jose Ignacio Candela, Joan Rocabert, Pedro RodriguezAbstract:Grid stability is one of the main concerns in renewable energies. The lack of inertia and their low capability to provide Frequency Support has created the need for implementing new control strategies to solve this problem. In current networks, Frequency and voltage Support are performed through synchronous generators, which provide an inherent grid Support due to the inertia presented in their mechanical rotors. Based on the same concept, renewable energies based on power converters have introduced synchronous controllers to emulate the dynamic behavior of synchronous generators and provide voltage and Frequency Support. However, most synchronous control strategies integrate their controllers as an add-on firmware embedded in each power converter, without presenting a coordinated synchronous performance when several converters operate in a PV power plant. The aggregation of several power converters operating with a coordinated synchronous response would be advantageous in these cases, since they can provide a harmonic response with an automatic power distribution when grid Support is required. This paper presents a synchronous control strategy for photovoltaic power plants, which manages several power converters as an aggregated synchronous system.
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Frequency Support Properties of the Synchronous Power Control for Grid-Connected Converters
IEEE Transactions on Industry Applications, 2019Co-Authors: Weiyi Zhang, Andres Tarraso, Joan Rocabert, Alvaro Luna, J. Ignacio Candela, Pedro RodriguezAbstract:Grid-connected power converters that integrate Frequency Support and inertia emulation functionalities have emerged in the last years. These features are promising for renewable energy-based power generation plants, as it permits such systems to contribute to enhance the power system stability. This paper discusses about three different active power control solutions that can be applied to grid-connected converters equipped with a synchronous power controller. For each solution, the detailed analytical relationship between the control parameters and the power loop dynamics is illustrated, and the local stability and dynamics are analyzed. The analysis and validation of Frequency Support functionalities are particularly addressed in this study, where the results obtained in a 10-kW experiment endorse the analysis; finally permitting to conclude that the synchronous power control offers good performance in terms of inertial response and droop characteristics.
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Frequency Support characteristics of grid interactive power converters based on the synchronous power controller
Iet Renewable Power Generation, 2017Co-Authors: Weiyi Zhang, Daniel Remon, Pedro RodriguezAbstract:Grid-interactive converters with primary Frequency control and inertia emulation have emerged and are promising for future renewable generation plants because of the contribution in power system stabilisation. This study gives a synchronous active power control solution for grid-interactive converters, as a way to emulate synchronous generators for inerita characteristics and load sharing. As design considerations, the virtual angle stability and transient response are both analysed, and the detailed implementation structure is also given without entailing any difficulty in practice. The analytical and experimental validation of Frequency Support characteristics differentiates the work from other publications on generator emulation control. The 10 kW simulation and experimental Frequency sweep tests on a regenerative source test bed present good performance of the proposed control in showing inertia and droop characteristics, as well as the controllable transient response.
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Frequency Support properties of the synchronous power control for grid-connected converters
2016 IEEE Energy Conversion Congress and Exposition (ECCE), 2016Co-Authors: Weiyi Zhang, Joan Rocabert, Alvaro Luna, J. Ignacio Candela, Daniel Remon, Pedro RodriguezAbstract:Grid-connected converters with primary Frequency control and inertia emulation have emerged and are promising for future renewable generation plants because of the contribution in power system stabilization. This paper gives a synchronous active power control solution for grid-connected converters. As design considerations, the virtual angle stability and transient response are both analyzed, and the detailed implementation structure is also given without entailing any difficulty in practice. The analysis and validation of Frequency Support characteristics are particularly addressed. The 10 kW simulation and experimental Frequency sweep tests on a regenerative source test bed present good performance of the proposed control in terms of showing inertia and droop characteristics, and the controllable transient response is also demonstrated.
Ayman Attya - One of the best experts on this subject based on the ideXlab platform.
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Provision of Frequency Support by Wind Power Plants: Assessment of Compliance with Grid Codes
2019 IEEE Milan PowerTech, 2019Co-Authors: Ayman AttyaAbstract:This paper implements and compares, from the compliance with grid code viewpoint, between the key concepts to enable wind power short-term Frequency Support using direct and indirect methods. The supplementary controllers that could be integrated into the wind turbine represent the direct methods. Meanwhile the indirect method is the integration of battery energy storage systems (BESS) to provide this crucial service. These methods are widely investigated in the literature where pitch de-loading is the main concept applied to provide direct Frequency Support, and the concept of kinetic energy (KE) extraction is also considered. The paper exploits the compliance with a certain generic Grid Code. The compliance tests are executed under different patterns of incident wind speed, including intermittent wind of high time resolution.
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Insights on the Provision of Frequency Support by Wind Power and the Impact on Energy Systems
IEEE Transactions on Sustainable Energy, 2018Co-Authors: Ayman Attya, Jose Luis Dominguez-garciaAbstract:This paper implements and compares between the key concepts to enable wind power short-term Frequency Support from electrical and mechanical loads perspectives. Pitch de-loading, kinetic energy extraction, and wind turbine (WTG) over-speeding are investigated, where each concept is integrated as a supplementary controller to the conventional controls of WTG. Different patterns of wind speed are examined, step-change and real intermittent of high resolution. The examined aggregated synchronous area has a relatively high wind penetration with Frequency Support. The overall dynamic inertia of the system is assessed to analyze the impact of the integrated Support methods and their key parameters. The coordination between synchronous areas and wind farms, which are interconnected through a multiterminal high-voltage direct-current network (MT-HVDC) is examined. A novel definition of the virtual inertia of MT-HVDC grid is proposed. Results show that pitch de-loading secures Support reserve most of the time, and kinetic energy extraction provides sustainable Support for a short interval, while accelerative de-loading could reach a compromise. The three methods are adaptable with the MT-HVDC holistic Frequency Support controller, with a slight advantage of kinetic energy extraction over the virtual inertia of the MT-HVDC. MATLAB/Simulink is the simulation environment.
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Frequency Support using doubly fed induction and reluctance wind turbine generators
International Journal of Electrical Power & Energy Systems, 2018Co-Authors: Ayman Attya, Sul Ademi, Milutin Jovanovic, Olimpo Anaya-laraAbstract:Abstract This paper presents the comparative computer simulations of a commercial doubly-fed induction generator (DFIG) and an emerging brushless doubly-fed reluctance generator (BDFRG) for grid-connected wind turbines in terms of Frequency Support based on the inertia emulation and blade pitching de-loading. The BDFRG features the low operation and maintenance cost by using a fractional inverter, and offers the high reliability of brushless structure with a simpler, more compact 2-stage gearbox design while still ensuring competitive performance to its popular slip-ring companion. The implemented benchmark is carefully designed to ascertain the relative capabilities of the two wind turbine generator technologies in providing this ancillary service. The results reveal that in spite of the fundamentally different operating principles, the DFIG and the BDFRG are highly aligned from the viewpoint of power system applications.
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A review on Frequency Support provision by wind power plants: Current and future challenges
Renewable and Sustainable Energy Reviews, 2018Co-Authors: Ayman Attya, Jose Luis Dominguez-garcia, Olimpo Anaya-laraAbstract:The continuing increase of wind energy penetration into power systems, in combination with the retirement of conventional generation, raises new challenges for the maintenance of power system stability. This paper presents a comprehensive review of wind power plant capabilities to provide Frequency Support and the corresponding methods available in the published literature are thoroughly analysed and compared. The topic is covered from different perspectives giving a comprehensive overview on the work carried out in this field. In addition, the integration of energy storage technologies and dispatching of wind farms during Frequency deviations are thoroughly discussed. Finally, technical challenges, future research lines and general recommendations are provided.
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ISGT Europe - Estimation of Frequency Support market indices using Monte Carlo simulation for wind power generation
2017 IEEE PES Innovative Smart Grid Technologies Conference Europe (ISGT-Europe), 2017Co-Authors: Ayman Attya, Jose Luis Dominguez-garcia, Olimpo Anaya-laraAbstract:The foreseen high penetration levels of renewable energy sources into modern power system will force these green power plants to provide full range of ancillary services. Consequently, the schemes and mechanisms of the markets of such services should be adapted to accommodate the intermittent and uncertain nature of renewable power generation. This paper develops a novel probabilistic method to evaluate the key indices of Frequency Support according to the present market practices. Focus will be brought to wind power generation, where three different concepts of Frequency Support are compared through the proposed estimation algorithm, which is based on Monte Carlo Simulation (MCS). This study also considers different ranges of wind speed. Results reflect the disability of current factors, which are used to calculate the incentives and rates of provided power and energy Support, to deal with wind power. It also reveals the average deviations between the applied Support methods from viewpoint of the estimated indices. Matlab/Simulink is the applied simulation environment, where supplementary controllers are integrated into the NREL 5MW benchmark to enable its provision for Frequency Support.
Olimpo Anaya-lara - One of the best experts on this subject based on the ideXlab platform.
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Frequency Support using doubly fed induction and reluctance wind turbine generators
International Journal of Electrical Power & Energy Systems, 2018Co-Authors: Ayman Attya, Sul Ademi, Milutin Jovanovic, Olimpo Anaya-laraAbstract:Abstract This paper presents the comparative computer simulations of a commercial doubly-fed induction generator (DFIG) and an emerging brushless doubly-fed reluctance generator (BDFRG) for grid-connected wind turbines in terms of Frequency Support based on the inertia emulation and blade pitching de-loading. The BDFRG features the low operation and maintenance cost by using a fractional inverter, and offers the high reliability of brushless structure with a simpler, more compact 2-stage gearbox design while still ensuring competitive performance to its popular slip-ring companion. The implemented benchmark is carefully designed to ascertain the relative capabilities of the two wind turbine generator technologies in providing this ancillary service. The results reveal that in spite of the fundamentally different operating principles, the DFIG and the BDFRG are highly aligned from the viewpoint of power system applications.
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A review on Frequency Support provision by wind power plants: Current and future challenges
Renewable and Sustainable Energy Reviews, 2018Co-Authors: Ayman Attya, Jose Luis Dominguez-garcia, Olimpo Anaya-laraAbstract:The continuing increase of wind energy penetration into power systems, in combination with the retirement of conventional generation, raises new challenges for the maintenance of power system stability. This paper presents a comprehensive review of wind power plant capabilities to provide Frequency Support and the corresponding methods available in the published literature are thoroughly analysed and compared. The topic is covered from different perspectives giving a comprehensive overview on the work carried out in this field. In addition, the integration of energy storage technologies and dispatching of wind farms during Frequency deviations are thoroughly discussed. Finally, technical challenges, future research lines and general recommendations are provided.
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ISGT Europe - Estimation of Frequency Support market indices using Monte Carlo simulation for wind power generation
2017 IEEE PES Innovative Smart Grid Technologies Conference Europe (ISGT-Europe), 2017Co-Authors: Ayman Attya, Jose Luis Dominguez-garcia, Olimpo Anaya-laraAbstract:The foreseen high penetration levels of renewable energy sources into modern power system will force these green power plants to provide full range of ancillary services. Consequently, the schemes and mechanisms of the markets of such services should be adapted to accommodate the intermittent and uncertain nature of renewable power generation. This paper develops a novel probabilistic method to evaluate the key indices of Frequency Support according to the present market practices. Focus will be brought to wind power generation, where three different concepts of Frequency Support are compared through the proposed estimation algorithm, which is based on Monte Carlo Simulation (MCS). This study also considers different ranges of wind speed. Results reflect the disability of current factors, which are used to calculate the incentives and rates of provided power and energy Support, to deal with wind power. It also reveals the average deviations between the applied Support methods from viewpoint of the estimated indices. Matlab/Simulink is the applied simulation environment, where supplementary controllers are integrated into the NREL 5MW benchmark to enable its provision for Frequency Support.
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Provision of Frequency Support by offshore wind farms connected via HVDC links
5th IET International Conference on Renewable Power Generation (RPG) 2016, 2016Co-Authors: Ayman Attya, Olimpo Anaya-laraAbstract:The high penetration levels of wind power will obligate wind farms to contribute to the mitigation of Frequency drops. Comprehensive case studies are presented to investigate the different methods of Frequency Support provision by wind power. The implemented test system is composed of an offshore wind farm connected to an external grid through a point-to-point HVDC link. Three different Frequency Support methods are compared; droop de-loading, battery storage banks and a mix between the two methods. Moreover, two different methods of sensing the Frequency drop, at the point of common coupling, by the wind farm are examined. The impact of the HVDC is highlighted, especially its role to transmit the power surge provided by the wind farm. A modified de-loading controller is developed and integrated to all the wind turbines, according to the executed case studies. Results show that the proposed Frequency Support solutions have almost similar impact on the natural Frequency response at the point of common coupling. The HVDC link does not worsen the Frequency response, and the fluctuations in voltage levels at onshore and offshore buses are very minor. DIGsILENT PowerFactory is integrated as a simulation environment.
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ISGT Europe - Novel metrics to quantify the impacts of Frequency Support provision methods by wind power
2016 IEEE PES Innovative Smart Grid Technologies Conference Europe (ISGT-Europe), 2016Co-Authors: Ayman Attya, Olimpo Anaya-lara, William LeitheadAbstract:This paper introduces two novel metrics to judge the capability and influence of wind power to provide virtual inertia response (i.e. Frequency Support). The first metric considers the generation unit (i.e. wind turbine generator (WTG)/wind farm (WF) vs. synchronous generator). This metric is applied to compare between three different methods of provision of Frequency Support. The second metric assess the improvement or hindering in Frequency response at the point of common coupling (PCC) between a WF and a synchronous area. This metric is critical especially to WFs that are connected via High Voltage Direct Current (HVDC) or Low-Frequency AC links. Both metrics are universal so that they could be applied to any Support method, and any power system. The first metric is applied to assess the virtual inertia response of an offshore WF, which is considered as a power plant along with the HVDC transmission link. Results assure the positive impact of the provision of Frequency Support by wind power. This impact is quantified could be used to tune Frequency Support controllers, and optimize system planning. It is verified that no obstacles are implied by the HVDC link to integrating Frequency Support methods, as the WF dominates the Support process.
Weiyi Zhang - One of the best experts on this subject based on the ideXlab platform.
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Frequency Support Properties of the Synchronous Power Control for Grid-Connected Converters
IEEE Transactions on Industry Applications, 2019Co-Authors: Weiyi Zhang, Andres Tarraso, Joan Rocabert, Alvaro Luna, J. Ignacio Candela, Pedro RodriguezAbstract:Grid-connected power converters that integrate Frequency Support and inertia emulation functionalities have emerged in the last years. These features are promising for renewable energy-based power generation plants, as it permits such systems to contribute to enhance the power system stability. This paper discusses about three different active power control solutions that can be applied to grid-connected converters equipped with a synchronous power controller. For each solution, the detailed analytical relationship between the control parameters and the power loop dynamics is illustrated, and the local stability and dynamics are analyzed. The analysis and validation of Frequency Support functionalities are particularly addressed in this study, where the results obtained in a 10-kW experiment endorse the analysis; finally permitting to conclude that the synchronous power control offers good performance in terms of inertial response and droop characteristics.
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Frequency Support characteristics of grid interactive power converters based on the synchronous power controller
Iet Renewable Power Generation, 2017Co-Authors: Weiyi Zhang, Daniel Remon, Pedro RodriguezAbstract:Grid-interactive converters with primary Frequency control and inertia emulation have emerged and are promising for future renewable generation plants because of the contribution in power system stabilisation. This study gives a synchronous active power control solution for grid-interactive converters, as a way to emulate synchronous generators for inerita characteristics and load sharing. As design considerations, the virtual angle stability and transient response are both analysed, and the detailed implementation structure is also given without entailing any difficulty in practice. The analytical and experimental validation of Frequency Support characteristics differentiates the work from other publications on generator emulation control. The 10 kW simulation and experimental Frequency sweep tests on a regenerative source test bed present good performance of the proposed control in showing inertia and droop characteristics, as well as the controllable transient response.
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Frequency Support properties of the synchronous power control for grid-connected converters
2016 IEEE Energy Conversion Congress and Exposition (ECCE), 2016Co-Authors: Weiyi Zhang, Joan Rocabert, Alvaro Luna, J. Ignacio Candela, Daniel Remon, Pedro RodriguezAbstract:Grid-connected converters with primary Frequency control and inertia emulation have emerged and are promising for future renewable generation plants because of the contribution in power system stabilization. This paper gives a synchronous active power control solution for grid-connected converters. As design considerations, the virtual angle stability and transient response are both analyzed, and the detailed implementation structure is also given without entailing any difficulty in practice. The analysis and validation of Frequency Support characteristics are particularly addressed. The 10 kW simulation and experimental Frequency sweep tests on a regenerative source test bed present good performance of the proposed control in terms of showing inertia and droop characteristics, and the controllable transient response is also demonstrated.
Nicolaos Antonio Cutululis - One of the best experts on this subject based on the ideXlab platform.
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Communication-Less Frequency Support from Offshore Wind Farms Connected to HVdc via Diode Rectifiers
2020Co-Authors: Oscar Saborío-romano, Ali Bidadfar, Jayachandra Naidu Sakamuri, Lorenzo Zeni, Ömer Göksu, Nicolaos Antonio CutululisAbstract:Before diode rectifier (DR) technology for connecting offshore wind farms (OWFs) to HVdc is deployed, in-depth studies are needed to assess the actual capabilities of DR-connected OWFs to contribute to the secure operation of the networks linked to them. This study assesses the capability of such an OWF to provide communication-less Frequency Support (CLFS) to an onshore ac network. It is shown that the HVdc link’s offshore terminal direct voltage can be estimated from measurements at the OWF’s point of connection with the DR platform. Two different methods are proposed for implementing CLFS in the OWF active power controls. In Method 1, the estimated offshore terminal direct voltage is used for estimating the onshore Frequency deviation. In Method 2, the actual offshore terminal direct voltage measurement is used instead. Unique features of the provision of CLFS from OWFs connected to HVdc via DRs are highlighted, and the dynamic and static performance of the CLFS control scheme is compared to that of the communication-based Frequency Support scheme. To assess the impact of parameter estimation errors on the provision of CLFS, a parametric sensitivity study is presented as well, and recommendations are given to increase accuracy.<br><br>The manuscript has been accepted for publication in IEEE Transactions on Sustainable Energy.
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Communication-Less Frequency Support from Offshore Wind Farms Connected to HVdc via Diode Rectifiers
2019Co-Authors: Oscar Saborío-romano, Ali Bidadfar, Jayachandra Naidu Sakamuri, Lorenzo Zeni, Ömer Göksu, Nicolaos Antonio CutululisAbstract:Before diode rectifier (DR) technology for connecting offshore wind farms (OWFs) to HVdc is deployed, in-depth studies are needed to assess the actual capabilities of DR-connected OWFs to contribute to the secure operation of the networks linked to them. This study assesses the capability of such an OWF to provide communication-less Frequency Support (CLFS) to an onshore ac network. It is shown that the HVdc link’s offshore terminal direct voltage can be estimated from measurements at the OWF’s point of connection with the DR platform. Two different methods are proposed for implementing CLFS in the OWF active power controls. In Method 1, the estimated offshore terminal direct voltage is used for estimating the onshore Frequency deviation. In Method 2, the actual offshore terminal direct voltage measurement is used instead. Unique features of the provision of CLFS from OWFs connected to HVdc via DRs are highlighted, and the dynamic and static performance of the CLFS control scheme is compared to that of the communication-based Frequency Support scheme. To assess the impact of parameter estimation errors on the provision of CLFS, a parametric sensitivity study is presented as well, and recommendations are given to increase accuracy.<br><br>The manuscript has been submitted to IEEE Transactions on Sustainable Energy.
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primary Frequency Support from offshore wind power plants connected to hvdc grids
IEEE PowerTech Conference, 2019Co-Authors: Ali Bidadfar, Nicolaos Antonio Cutululis, Oscar Saborioromano, Jayachandra N Sakamuri, Mufit Altin, Poul Ejnar SørensenAbstract:Contribution to the power systems’ Frequency Support is expected to be one of the essential ancillary services that wind power plants (WPPs) shall provide. The high-voltage DC (HVDC) connected offshore WPPs may provide this service with and without using fast communication links between onshore and offshore. In the case of offshore HVDC grid, implementing the communication-less Frequency Support is challenging. Although it increases the reliability of the Frequency control, among other challenges, it is not straightforward to comply with relevant grid code requirements. In this paper, this issue is mathematically described and a static model is developed to calculate the deviation of various electrical parameters of an HVDC grid in case of Frequency drop on the land ac systems. A solution for the aforementioned problem is presented and its associated concerns are addressed. The study is verified by simulations of a four terminals dc grid with two offshore WPPs and two inland ac systems.
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Frequency Support capability of variable speed wind turbine based on electromagnetic coupler
Renewable Energy, 2015Co-Authors: Rui You, Braulio Barahona, Jianyun Chai, Nicolaos Antonio CutululisAbstract:In the variable speed wind turbine based on electromagnetic coupler (WT-EMC), a synchronous generator is directly coupled with grid. So like conventional power plants WT-EMC is able to Support grid Frequency inherently. But due to the reduced inertia of synchronous generator, its Frequency Support capability has to be enhanced. In this paper, the Frequency Support capability of WT-EMC is studied at three typical wind conditions and with two control strategies—droop control and inertial control to enhance its Frequency Support capability. The synchronous generator speed, more stable than the grid Frequency which is the input signal for Type 3 and Type 4 wind turbine Frequency Support controller, is used for the calculation of WT-EMC supplementary torque command. The integrated simulation environment based on the aeroelastic code HAWC2 and software Matlab/Simulink is used to build a 2 MW WT-EMC model and study the Frequency Support capability of a wind farm consisting of WT-EMC.
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Assessment of the impact of Frequency Support on DFIG wind turbine loads
2013Co-Authors: Braulio Barahona Garzon, Rui You, Nicolaos Antonio Cutululis, Anca Daniela Hansen, Poul Ejnar SørensenAbstract:This study presents models and tools for the assessment of the impact that providing Frequency Support has on doubly-fed generator (DFIG) wind turbine structural loads and drive train. The focus is on primary Frequency Support, aiming at quantifying the impact on wind turbines acting as Frequency containment reserve and providing inertial response. The sensitivity of wind turbine load indicators—loadduration-distribution and maximum load values—to inertial response control actions and different torsional models of drive train is investigated. The analysis is done by co-simulations of an aeroelastic code and electrical models. In this simulation framework, the impact that power system conditions can have on wind turbines, and vice versa the Support that wind turbines can offer to the power system can be investigated.
