The Experts below are selected from a list of 117 Experts worldwide ranked by ideXlab platform

Bharath Venkatesh - One of the best experts on this subject based on the ideXlab platform.

  • Three-Phase Unbalanced Power Flow Using a ??-Model of Controllable AC-DC Converters
    IEEE Transactions on Power Systems, 2016
    Co-Authors: C. Opathella, Bharath Venkatesh
    Abstract:

    —Microgrids are unique in that they can combine unbalanced three-phase systems with other AC and DC network sections, which may include a range of renewable energy sources, energy storage elements, and controllable AC-DC converters. Existing unbalanced power flow techniques such as the Ladder Iterative Technique and the three-phase Newton-Raphson (NR) method can analyze microgrids in sections but lack a complete system representation. Hence, there is a need for a power flow algorithm that considers the complete system model and solves it. A novel -model of a controllable AC-DC converter and a single set of power balance equations for modeling a grid com-prising multiple three-phase AC and DC sections is proposed. The -model of a controllable AC-DC converter enables its inclusion into the network bus admittance matrix (YBUS) along with three-phase AC and DC network sections. Verification of the -model is also described in the paper. The results of power flow studies with three-phase balanced and unbalanced AC and DC network sections are presented. The outcome of the -model verification Study and power flow Study show that the proposed -model is consistent and accurate. While the proposed model was developed for microgrids, it is applicable for all power system analysis applications. Index Terms—Microgrids, three-phase power flow, power distri-bution systems, -model, AC-DC power converters.

C. Opathella - One of the best experts on this subject based on the ideXlab platform.

  • Three-Phase Unbalanced Power Flow Using a ??-Model of Controllable AC-DC Converters
    IEEE Transactions on Power Systems, 2016
    Co-Authors: C. Opathella, Bharath Venkatesh
    Abstract:

    —Microgrids are unique in that they can combine unbalanced three-phase systems with other AC and DC network sections, which may include a range of renewable energy sources, energy storage elements, and controllable AC-DC converters. Existing unbalanced power flow techniques such as the Ladder Iterative Technique and the three-phase Newton-Raphson (NR) method can analyze microgrids in sections but lack a complete system representation. Hence, there is a need for a power flow algorithm that considers the complete system model and solves it. A novel -model of a controllable AC-DC converter and a single set of power balance equations for modeling a grid com-prising multiple three-phase AC and DC sections is proposed. The -model of a controllable AC-DC converter enables its inclusion into the network bus admittance matrix (YBUS) along with three-phase AC and DC network sections. Verification of the -model is also described in the paper. The results of power flow studies with three-phase balanced and unbalanced AC and DC network sections are presented. The outcome of the -model verification Study and power flow Study show that the proposed -model is consistent and accurate. While the proposed model was developed for microgrids, it is applicable for all power system analysis applications. Index Terms—Microgrids, three-phase power flow, power distri-bution systems, -model, AC-DC power converters.

  • An intelligent wind farm model for three-phase unbalanced power flow studies
    2014 4th International Conference on Engineering Technology and Technopreneuship (ICE2T), 2014
    Co-Authors: C. Opathella, D. Cheng, Bala Venkatesh
    Abstract:

    With the rapid growth of wind power penetration in power systems, researchers focus on methods to accurately model wind generators in power flow studies. There are several accurate wind generator models which capture the voltage dependence of power output per each phase of wind generators. These models have been built using individual models of all the constituent components of wind generators. Furthermore, these models comprise complex nonlinear equations and hence inevitably slow down power flow studies. When wind farms are modeled with this approach, they become very complex and cumbersome to be integrated into power flow studies. On the other hand if the power output of a wind farms is simplistically assumed as fixed injection value neglecting the voltage dependence of power output per phase, the resultant power flow solution will not be accurate due to over simplification. In this paper a new wind farm model is built using Artificial Neural Networks (ANN). The procedure of building ANN models is explained using a small wind farm with five wind generators. The ANN wind farm models estimate power output per phase using three-phase voltages and wind speeds. A power flow Study with this ANN model, a simple fixed power model and a detailed nonlinear model is reported in this paper with sufficient comparisons. The proposed ANN model is 80 times faster than a complete nonlinear wind farm model and as accurate as the nonlinear wind farm model.

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

  • Power flow control and power flow studies for systems with FACTS devices
    IEEE Transactions on Power Systems, 1998
    Co-Authors: Douglas J Gotham, G. T. Heydt
    Abstract:

    In this paper, the modeling of flexible AC transmission system (FACTS) devices for power flow studies and the role of that modeling in the Study of FACTS devices for power flow control are discussed. FACTS devices are solid-state power converters that have the capability of control of various electrical parameters in transmission circuits. A number of power flow Study programs were developed in order to model various types of FACTS devices. Three main generic types of FACTS devices are suggested and the integration of those devices into power flow studies, studies relating to wheeling and interchange power flow control are illustrated.

  • power flow control and power flowst es for syste s facts devices
    1998
    Co-Authors: Douglas J Gotham, G. T. Heydt
    Abstract:

    In this paper, the modeling of flexible AC transmission system (FACTS) devices for power flow studies and the role of that modeling in the Study of FACTS devices for power flow control are discussed. FACTS devices are solid state converters that have the capability of control of various electrical parameters in transmission circuits. A number of power flow Study programs were developed in order to model various types of FACTS devices. Three main generic types of FACTS devices are suggested and the integration of those devices into power flow studies, studies relating to wheeling, and inter- change power flow control are illustrated.

  • POWER FLOW CONTROL AND POWER FLOWST~~ES FOR SYSTE~S FACTS DEVICES
    1998
    Co-Authors: Douglas J Gotham, G. T. Heydt
    Abstract:

    In this paper, the modeling of flexible AC transmission system (FACTS) devices for power flow studies and the role of that modeling in the Study of FACTS devices for power flow control are discussed. FACTS devices are solid state converters that have the capability of control of various electrical parameters in transmission circuits. A number of power flow Study programs were developed in order to model various types of FACTS devices. Three main generic types of FACTS devices are suggested and the integration of those devices into power flow studies, studies relating to wheeling, and inter- change power flow control are illustrated.

Hsiao-dong Chiang - One of the best experts on this subject based on the ideXlab platform.

  • ISCAS - Convergence regions of Newton method in power flow studies: Numerical studies
    2013 IEEE International Symposium on Circuits and Systems (ISCAS2013), 2013
    Co-Authors: Jiao-jiao Deng, Hsiao-dong Chiang, Tian-qi Zhao, Yong Tang, Yi Wang
    Abstract:

    Power flow Study is a fundamental task of power system operation and planning. Of the several methods developed in commercial package for power flow Study, the Newton-Raphson method is the most successful one. It is however well recognized that the NR method may diverge in power flow Study. In this paper, we numerically Study the convergence regions of power flow solutions using Newton-Raphson(NR) method. This Study of convergence region is motivated by the need to determine an initial guess which converges to one of the power flow solution. It will be numerically shown that the convergence region of NR method, if exist, has a fractal boundary and is hence sensitive to initial conditions. Several fractal features will be investigated considering the convergence regions of power flow at the base case and at various loading conditions, and with different load models. An IEEE 14-bus system will be used to illustrate the fractal boundary via numerical results.

  • Fast Newton-FGMRES Solver for Large-Scale Power Flow Study
    IEEE Transactions on Power Systems, 2010
    Co-Authors: Yi-shan Zhang, Hsiao-dong Chiang
    Abstract:

    A fast Newton-FGMRES method for power flow calculations is proposed in this paper. Three accelerating schemes to speed up the Newton-FGMRES method are proposed. Numerical studies show that the proposed fast Newton-FGMRES method consistently outperforms the traditional Newton-GMRES method and Newton-LU method on two practical power systems-one with 12 000 buses, another with 21 000 buses. For the 21 000-bus system, the fast Newton-FGMRES method can be 45.7% faster than the traditional Newton-LU method.

  • Fast Newton-FGMRES solver for large-scale power flow Study
    2009 IEEE Power & Energy Society General Meeting, 2009
    Co-Authors: Yi-shan Zhang, Hsiao-dong Chiang
    Abstract:

    A fast Newton-FGMRES method for power flow calculations is presented in this paper. Three accelerating schemes to speed up Newton-FGMRES method are proposed. Numerical studies show that the proposed fast Newton-FGMRES method consistently outperforms the traditional Newton-GMRES method and Newton-LU method on two practical power systems — one with 12000 buses, another with 21000 buses — indicating that the proposed fast Newton-FGMRES method can be a good alternative to power flow calculations.

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

  • Optimal microgrid control and Power-Flow Study with different bidding policies by using powerworld simulator
    IEEE Transactions on Sustainable Energy, 2014
    Co-Authors: Dong Zhang, Peng Zeng, Shuhui Li, Chuanzhi Zang
    Abstract:

    For a microgrid (MG) to participate in a real-time and demand-side bidding market, high-level control strategies aiming at optimizing the operation of the MG are necessary. One of the difficulties for research of a competitive MG power market is the absence of efficient computational tools. Although many commercial power system simulators are available, these power system simulators are usually not directly applicable to solve the optimal power dispatch problem for an MG power market and to perform MG Power-Flow Study. This paper analyzes the typical MG market policies and investigates how these policies can be converted in such a way that one can use commercial power system software for MG power market Study. The paper also develops a mechanism suitable for the Power-Flow Study of an MG containing inverter-interfaced distributed energy sources. The extensive simulation analyses are conducted for grid-tied and islanded operations of a benchmark MG network. © 2013 IEEE.

  • Microgrid power flow Study in grid-connected and islanding modes under different converter control strategies
    2012 IEEE Power and Energy Society General Meeting, 2012
    Co-Authors: Shuhui Li, J. Proano, Dong Zhang
    Abstract:

    The organic growth and evolution of the future smart grid is expected to emerge as a well-planned plug-and-play integration of smart microgrids. A microgrid normally comprises a variety of inverter-interfaced distributed energy resources such as solar photovoltaic arrays, wind turbines, microturbines, fuel cells, energy storage devices, and controllable loads, in which a key issue is how to manage a microgrid in grid-connected and islanding modes under different converter control strategies. This paper presents a microgrid power flow Study under variable load and generation conditions. The paper considers typical properties of inverter-interfaced microsources, including PQ inverter, PV inverter, and converter rated current and linear modulation constraints in the power flow Study. A benchmark network is built by using PowerWorld simulator. But, variable load and generation data is created by using other software tools and then loaded into the PowerWorld simulator. The benchmark network is studied by considering different microgrid operation scenarios. Simulation evaluation demonstrates how the microgrid behaves under different power converter operating conditions in grid-connected and islanding modes, respectively.