The Experts below are selected from a list of 10338 Experts worldwide ranked by ideXlab platform

Nick Jenkins - One of the best experts on this subject based on the ideXlab platform.

  • Fault ride through of fully rated converter wind turbines with AC and DC transmission systems
    IET Renewable Power Generation, 2009
    Co-Authors: G Ramtharan, F.m. Hughes, J. B. Ekanayake, A Arulampalam, Nick Jenkins
    Abstract:

    Fault ride through of fully rated converter wind turbines in an offshore wind farm connected to onshore network via either high voltage AC (HVAC) or high voltage DC (HVDC) transmission is described. Control of the generators and the grid side converters is shown using vector control techniques. A de-loading scheme was used to protect the wind turbine DC link capacitors from over voltage. How de-loading of each generator aids the fault ride through of the wind farm connected through HVAC transmission is demonstrated. The voltage recovery of the AC network during the fault was enhanced by increasing the reactive power current of the wind turbine grid side converter. A practical fault ride through protection scheme for a wind farm connected through an HVDC link is to employ a chopper circuit on the HVDC link. Two alternatives to this approach are also discussed. The first involves de-loading the wind farm on detection of the fault, which requires Communication of the fault condition to each wind turbine of the wind farm. The second scheme avoids this complex Communication Requirement by transferring the fault condition via control of the HVDC link to the offshore converter. The fault performances of the three schemes are simulated and the results were used to assess their respective capabilities.

  • Fault ride through of fully rated converter wind turbines with AC and DC transmission
    IET Renewable Power Generation, 2009
    Co-Authors: G Ramtharan, F.m. Hughes, J. B. Ekanayake, A Arulampalam, Nick Jenkins
    Abstract:

    Fault ride through of fully rated converter wind turbines in an offshore wind farm connected to onshore network via either high voltage AC (HVAC) or high voltage DC (HVDC) transmission is described. Control of the generators and the grid side converters is shown using vector control techniques. A de-loading scheme was used to protect the wind turbine DC link capacitors from over voltage. How de-loading of each generator aids the fault ride through of the wind farm connected through HVAC transmission is demonstrated. The voltage recovery of the AC network during the fault was enhanced by increasing the reactive power current of the wind turbine grid side converter. A practical fault ride through protection scheme for a wind farm connected through an HVDC link is to employ a chopper circuit on the HVDC link. Two alternatives to this approach are also discussed. The first involves de-loading the wind farm on detection of the fault, which requires Communication of the fault condition to each wind turbine of the wind farm. The second scheme avoids this complex Communication Requirement by transferring the fault condition via control of the HVDC link to the offshore converter. The fault performances of the three schemes are simulated and the results were used to assess their respective capabilities.

Husheng Li - One of the best experts on this subject based on the ideXlab platform.

  • Communication Efficient Coreset Sampling for Distributed Learning
    2018 IEEE 19th International Workshop on Signal Processing Advances in Wireless Communications (SPAWC), 2018
    Co-Authors: Husheng Li
    Abstract:

    Distributedly learning through wireless network becomes one of the future features with the growth of computation power for devices. Communication becomes the bottleneck for such distributed framework. In this paper, distributed learning is studied using the approach of coreset. In the context of classification, an algorithm of coreset construction is proposed to reduce the redundancy of data and thus the Communication Requirement, similarly to source coding in traditional data Communications. The coreset based sampling is robust to adversary distribution, thus leading to potential applications in distributed learning systems. Both theoretical and numerical analyses are provided to demonstrate the proposed framework.

  • does feedback control always reduce entropy Communication Requirement in smart grid
    Global Communications Conference, 2017
    Co-Authors: Husheng Li
    Abstract:

    In cyber physical systems (CPSs) such as smart grids, feedback control confines the system state around the desired one. To monitor the system state, Communications are needed to convey the system observations. Entropy is used to bridge the control and Communications, since the control action results in a low entropy system. Meanwhile Communications arise from positive entropy (i.e., uncertainty), and a lower entropy information source requires less Communications for description. However, it is not clear whether the control action always reduces the entropy (thus Communications). Hence, two types of entropy reductions, namely reduction in time and reduction when compared with open loop control, are studied. Sufficient conditions for entropy reduction and increase are derived, respectively. Numerical results show that the feedback control reduces the entropy, thus the Communication Requirement, in typical setups of smart grids. However, there also exist situations in which the feedback control increases entropy, thus demanding more Communications.

  • GLOBECOM - Does Feedback Control Always Reduce Entropy/Communication Requirement in Smart Grid?
    GLOBECOM 2017 - 2017 IEEE Global Communications Conference, 2017
    Co-Authors: Husheng Li
    Abstract:

    In cyber physical systems (CPSs) such as smart grids, feedback control confines the system state around the desired one. To monitor the system state, Communications are needed to convey the system observations. Entropy is used to bridge the control and Communications, since the control action results in a low entropy system. Meanwhile Communications arise from positive entropy (i.e., uncertainty), and a lower entropy information source requires less Communications for description. However, it is not clear whether the control action always reduces the entropy (thus Communications). Hence, two types of entropy reductions, namely reduction in time and reduction when compared with open loop control, are studied. Sufficient conditions for entropy reduction and increase are derived, respectively. Numerical results show that the feedback control reduces the entropy, thus the Communication Requirement, in typical setups of smart grids. However, there also exist situations in which the feedback control increases entropy, thus demanding more Communications.

  • Does Feedback Control Always Reduce Entropy/Communication Requirement in Smart Grid?
    GLOBECOM 2017 - 2017 IEEE Global Communications Conference, 2017
    Co-Authors: Husheng Li
    Abstract:

    In cyber physical systems (CPSs) such as smart grids, feedback control confines the system state around the desired one. To monitor the system state, Communications are needed to convey the system observations. Entropy is used to bridge the control and Communications, since the control action results in a low entropy system. Meanwhile Communications arise from positive entropy (i.e., uncertainty), and a lower entropy information source requires less Communications for description. However, it is not clear whether the control action always reduces the entropy (thus Communications). Hence, two types of entropy reductions, namely reduction in time and reduction when compared with open loop control, are studied. Sufficient conditions for entropy reduction and increase are derived, respectively. Numerical results show that the feedback control reduces the entropy, thus the Communication Requirement, in typical setups of smart grids. However, there also exist situations in which the feedback control increases entropy, thus demanding more Communications.

  • Communications for distributed state estimation in CPSs with application in smart grids
    2015 IEEE International Conference on Smart Grid Communications (SmartGridComm), 2015
    Co-Authors: Husheng Li, Ju Bin Song
    Abstract:

    Topological entropy is a key quantity characterizing the complexity, or the information generation rate, of deterministic dynamical process. It provides the lower bound on the amount of Communications for reliable state estimation in cyber physical systems (CPSs). In order to study distributed state estimation in CPSs, product topological entropy, based on product covering and motivated by the theory of Communication complexity, is proposed. Three similar definitions of product topological entropy are proposed and compared, which are applied to the evaluation of the Communication Requirement in distributed system state estimation. Algorithms for numerically and approximately computing the product topological entropy are proposed and then applied in the context of smart grids.

G Ramtharan - One of the best experts on this subject based on the ideXlab platform.

  • Fault ride through of fully rated converter wind turbines with AC and DC transmission systems
    IET Renewable Power Generation, 2009
    Co-Authors: G Ramtharan, F.m. Hughes, J. B. Ekanayake, A Arulampalam, Nick Jenkins
    Abstract:

    Fault ride through of fully rated converter wind turbines in an offshore wind farm connected to onshore network via either high voltage AC (HVAC) or high voltage DC (HVDC) transmission is described. Control of the generators and the grid side converters is shown using vector control techniques. A de-loading scheme was used to protect the wind turbine DC link capacitors from over voltage. How de-loading of each generator aids the fault ride through of the wind farm connected through HVAC transmission is demonstrated. The voltage recovery of the AC network during the fault was enhanced by increasing the reactive power current of the wind turbine grid side converter. A practical fault ride through protection scheme for a wind farm connected through an HVDC link is to employ a chopper circuit on the HVDC link. Two alternatives to this approach are also discussed. The first involves de-loading the wind farm on detection of the fault, which requires Communication of the fault condition to each wind turbine of the wind farm. The second scheme avoids this complex Communication Requirement by transferring the fault condition via control of the HVDC link to the offshore converter. The fault performances of the three schemes are simulated and the results were used to assess their respective capabilities.

  • Fault ride through of fully rated converter wind turbines with AC and DC transmission
    IET Renewable Power Generation, 2009
    Co-Authors: G Ramtharan, F.m. Hughes, J. B. Ekanayake, A Arulampalam, Nick Jenkins
    Abstract:

    Fault ride through of fully rated converter wind turbines in an offshore wind farm connected to onshore network via either high voltage AC (HVAC) or high voltage DC (HVDC) transmission is described. Control of the generators and the grid side converters is shown using vector control techniques. A de-loading scheme was used to protect the wind turbine DC link capacitors from over voltage. How de-loading of each generator aids the fault ride through of the wind farm connected through HVAC transmission is demonstrated. The voltage recovery of the AC network during the fault was enhanced by increasing the reactive power current of the wind turbine grid side converter. A practical fault ride through protection scheme for a wind farm connected through an HVDC link is to employ a chopper circuit on the HVDC link. Two alternatives to this approach are also discussed. The first involves de-loading the wind farm on detection of the fault, which requires Communication of the fault condition to each wind turbine of the wind farm. The second scheme avoids this complex Communication Requirement by transferring the fault condition via control of the HVDC link to the offshore converter. The fault performances of the three schemes are simulated and the results were used to assess their respective capabilities.

F.m. Hughes - One of the best experts on this subject based on the ideXlab platform.

  • Fault ride through of fully rated converter wind turbines with AC and DC transmission systems
    IET Renewable Power Generation, 2009
    Co-Authors: G Ramtharan, F.m. Hughes, J. B. Ekanayake, A Arulampalam, Nick Jenkins
    Abstract:

    Fault ride through of fully rated converter wind turbines in an offshore wind farm connected to onshore network via either high voltage AC (HVAC) or high voltage DC (HVDC) transmission is described. Control of the generators and the grid side converters is shown using vector control techniques. A de-loading scheme was used to protect the wind turbine DC link capacitors from over voltage. How de-loading of each generator aids the fault ride through of the wind farm connected through HVAC transmission is demonstrated. The voltage recovery of the AC network during the fault was enhanced by increasing the reactive power current of the wind turbine grid side converter. A practical fault ride through protection scheme for a wind farm connected through an HVDC link is to employ a chopper circuit on the HVDC link. Two alternatives to this approach are also discussed. The first involves de-loading the wind farm on detection of the fault, which requires Communication of the fault condition to each wind turbine of the wind farm. The second scheme avoids this complex Communication Requirement by transferring the fault condition via control of the HVDC link to the offshore converter. The fault performances of the three schemes are simulated and the results were used to assess their respective capabilities.

  • Fault ride through of fully rated converter wind turbines with AC and DC transmission
    IET Renewable Power Generation, 2009
    Co-Authors: G Ramtharan, F.m. Hughes, J. B. Ekanayake, A Arulampalam, Nick Jenkins
    Abstract:

    Fault ride through of fully rated converter wind turbines in an offshore wind farm connected to onshore network via either high voltage AC (HVAC) or high voltage DC (HVDC) transmission is described. Control of the generators and the grid side converters is shown using vector control techniques. A de-loading scheme was used to protect the wind turbine DC link capacitors from over voltage. How de-loading of each generator aids the fault ride through of the wind farm connected through HVAC transmission is demonstrated. The voltage recovery of the AC network during the fault was enhanced by increasing the reactive power current of the wind turbine grid side converter. A practical fault ride through protection scheme for a wind farm connected through an HVDC link is to employ a chopper circuit on the HVDC link. Two alternatives to this approach are also discussed. The first involves de-loading the wind farm on detection of the fault, which requires Communication of the fault condition to each wind turbine of the wind farm. The second scheme avoids this complex Communication Requirement by transferring the fault condition via control of the HVDC link to the offshore converter. The fault performances of the three schemes are simulated and the results were used to assess their respective capabilities.

A Arulampalam - One of the best experts on this subject based on the ideXlab platform.

  • Fault ride through of fully rated converter wind turbines with AC and DC transmission systems
    IET Renewable Power Generation, 2009
    Co-Authors: G Ramtharan, F.m. Hughes, J. B. Ekanayake, A Arulampalam, Nick Jenkins
    Abstract:

    Fault ride through of fully rated converter wind turbines in an offshore wind farm connected to onshore network via either high voltage AC (HVAC) or high voltage DC (HVDC) transmission is described. Control of the generators and the grid side converters is shown using vector control techniques. A de-loading scheme was used to protect the wind turbine DC link capacitors from over voltage. How de-loading of each generator aids the fault ride through of the wind farm connected through HVAC transmission is demonstrated. The voltage recovery of the AC network during the fault was enhanced by increasing the reactive power current of the wind turbine grid side converter. A practical fault ride through protection scheme for a wind farm connected through an HVDC link is to employ a chopper circuit on the HVDC link. Two alternatives to this approach are also discussed. The first involves de-loading the wind farm on detection of the fault, which requires Communication of the fault condition to each wind turbine of the wind farm. The second scheme avoids this complex Communication Requirement by transferring the fault condition via control of the HVDC link to the offshore converter. The fault performances of the three schemes are simulated and the results were used to assess their respective capabilities.

  • Fault ride through of fully rated converter wind turbines with AC and DC transmission
    IET Renewable Power Generation, 2009
    Co-Authors: G Ramtharan, F.m. Hughes, J. B. Ekanayake, A Arulampalam, Nick Jenkins
    Abstract:

    Fault ride through of fully rated converter wind turbines in an offshore wind farm connected to onshore network via either high voltage AC (HVAC) or high voltage DC (HVDC) transmission is described. Control of the generators and the grid side converters is shown using vector control techniques. A de-loading scheme was used to protect the wind turbine DC link capacitors from over voltage. How de-loading of each generator aids the fault ride through of the wind farm connected through HVAC transmission is demonstrated. The voltage recovery of the AC network during the fault was enhanced by increasing the reactive power current of the wind turbine grid side converter. A practical fault ride through protection scheme for a wind farm connected through an HVDC link is to employ a chopper circuit on the HVDC link. Two alternatives to this approach are also discussed. The first involves de-loading the wind farm on detection of the fault, which requires Communication of the fault condition to each wind turbine of the wind farm. The second scheme avoids this complex Communication Requirement by transferring the fault condition via control of the HVDC link to the offshore converter. The fault performances of the three schemes are simulated and the results were used to assess their respective capabilities.