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Power Flow (power + flow)

Distribution by Scientific Domains
Engineering100%
Distribution within Engineering
Power Technology & Power Engineering83%
General & Introductory Electrical & Electronics Engineering16%

Terms modified by Power Flow

  • power flow controller
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    Selected Abstracts

    A new algorithm for reactive power management and pricing in an open access environment

    EUROPEAN TRANSACTIONS ON ELECTRICAL POWER, Issue 2 2008
    G. Reza Yousefi
    Abstract In deregulated electricity markets, reactive power is one of the ancillary services that is provided by the Independent System Operator (ISO). In this paper we propose a new algorithm to ,tune' reactive power resources with the objectives of minimizing active power losses and optimizing system voltage profile and stability. In our solution, we assume that reactive power resources are either owned by or are under long-term contracts with the ISO. The optimization problem is solved as an Extended Multi-objective Optimal Power Flow (EMOPF) problem using Lexico Graphic Method (LGM). Thereafter, using the concept of Fair Resource Allocation (FRA), the cost of reactive power is allocated to existing transactions. The application of the algorithm to a test system is also presented. Copyright © 2007 John Wiley & Sons, Ltd. [source]

    Operational and structural optimization of multi-carrier energy systems

    EUROPEAN TRANSACTIONS ON ELECTRICAL POWER, Issue 5 2006
    Martin Geidl
    Abstract This paper presents an approach for the combined optimization of energy systems including multiple energy carriers such as electricity, natural gas, and district heat. Power flow and conversion between the different energy infrastructures are described as multi-input multi-output coupling, what enables simple analysis and optimization of the flows. While previous work deals with operational optimization (multi-carrier optimal dispatch and power flow), this paper focuses on optimization of the couplings between the different networks, that is the structure of the system. Copyright © 2006 John Wiley & Sons, Ltd. [source]

    Coordinated voltage control of transformer taps with provision for hierarchical structure in power system

    ELECTRICAL ENGINEERING IN JAPAN, Issue 4 2009
    Yoshiki Nakachi
    Abstract Participation of distributed generators (DGs), such as wind turbines, cogeneration systems, etc., is a natural trend from an ecological point of view and will continue to increase. The outputs of these DGs mainly depend on weather conditions but do not correspond to the changes of electrical load demand necessarily. On the other hand, due to deregulation of the electric power market, the power flow in a power system will uncertainly vary with several power transactions. Thus, complex power flow by DGs or transactions will cause voltage deviation. It will be difficult to sustain the voltage quality by using conventional voltage/reactive power control in the near future. In this paper, in order to avoid such voltage deviation and to decrease the frequency of transformer tap operations, the coordinated voltage control scheme of transformer taps on account of hierarchical structure in the power system is proposed. In the proposed scheme, integral of voltage deviation at each layer bus is applied to decide the timing of each transformer tap operation. Numerical simulations confirm that the proposed scheme is able to respond to every condition on voltage deviation. © 2008 Wiley Periodicals, Inc. Electr Eng Jpn, 166(4): 48,55, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20531 [source]

    Optimal methodology for distribution systems reconfiguration based on OPF and solved by decomposition technique

    EUROPEAN TRANSACTIONS ON ELECTRICAL POWER, Issue 6 2010
    H. M. Khodr
    Abstract This paper presents a new and efficient methodology for distribution network reconfiguration integrated with optimal power flow (OPF) based on a Benders decomposition approach. The objective minimizes power losses, balancing load among feeders and subject to constraints: capacity limit of branches, minimum and maximum power limits of substations or distributed generators, minimum deviation of bus voltages and radial optimal operation of networks. The Generalized Benders decomposition algorithm is applied to solve the problem. The formulation can be embedded under two stages; the first one is the Master problem and is formulated as a mixed integer non-linear programming problem. This stage determines the radial topology of the distribution network. The second stage is the Slave problem and is formulated as a non-linear programming problem. This stage is used to determine the feasibility of the Master problem solution by means of an OPF and provides information to formulate the linear Benders cuts that connect both problems. The model is programmed in GAMS. The effectiveness of the proposal is demonstrated through two examples extracted from the literature. Copyright © 2009 John Wiley & Sons, Ltd. [source]

    Optimal production cost of the power producers with linear ramp model using FDR PSO algorithm

    EUROPEAN TRANSACTIONS ON ELECTRICAL POWER, Issue 2 2010
    M. Anitha
    Abstract In practice, the power producers have to be rescheduled for power generation beyond their power limits to meet vulnerable situations like credible contingency and increase in load conditions. During this process, the ramping cost is incurred if they violate their permissible elastic limits. In this paper, optimal production costs of the power producers are computed with ramping cost considering stepwise and piecewise linear ramp rate limits using fitness distance ratio particle swarm optimization (FDR PSO) algorithm. Transient stability constraints are also considered while formulating the optimal power flow (OPF) problem as additional rotor angle inequality constraints. The proposed algorithm is demonstrated on a practical 39 bus New England and 62 bus Indian Utility system with different case studies. Copyright © 2008 John Wiley & Sons, Ltd. [source]

    An efficient methodology for security assessment of power systems based on distributed optimal power flow

    EUROPEAN TRANSACTIONS ON ELECTRICAL POWER, Issue 3 2003
    D. Hur
    This paper presents an algorithm for the parallel solution of the security constrained optimal power flow (SCOPF) problem in a decentralized framework, consisting of regions, using a price-based mechanism that models each region as an economic unit. We first solve the distributed optimal power flow (OPF) problem to determine the maximum secure simultaneous transfer capability of each tie-line between adjacent regions by taking only the security constraints imposed on the tie-lines into account. In this paper, the line outage distribution factors (LODF) calculated at the current state are used to formulate the appended constraints. Once the secure transfer capability of each tie-line is determined, the intra-regional SCOPF is performed using the conventional linear programming (LP) approach. A description on the inclusion of security constraints with distributed OPF algorithm will be given, followed by the case study for Korea Electric Power System. [source]

    Steady-state power flow and voltage control by unified power-flow controllers, part 2: Applications

    EUROPEAN TRANSACTIONS ON ELECTRICAL POWER, Issue 2 2000
    Y. H. Song
    The unifiedpower-flowcontroller(UPFC) isa powerfuldeviceforthe reliejroj'transmission constraints. Part 1 of the paper proposes novel steady-state modelling and control algorithms for the study of UPFC, which use power-injection models to derive control parameters for UPFC to achieve the required line active power control and bus-voltage support. The proposed method does not change the symmetrical structures of Jacobian matrix, avoids the initialisations of control parameters and can cover a wide control range of UPFC due to the characteristics of optimal multiplier power-flow algorithms employed. This paper describes in detail the applications of the proposed theory in a 28-node system. The convergence of controlled power flow is analysed. Control performance has been evaluated. The numerical results presented clearly illustrate the effectiveness of the proposed approach. [source]

    Distributed-series compensator for controlling voltage in distribution line with clustered distributed generations

    IEEJ TRANSACTIONS ON ELECTRICAL AND ELECTRONIC ENGINEERING, Issue 3 2009
    Rejeki Simanjorang Member
    Abstract A method of controlling voltage profile in distribution line with many distributed generations (DGs) using distributed-series compensator (D-SC) is proposed. These DGs are assumed to be clustered photovoltaics (PVs) which are installed at residential area. A large power injected by PVs may result in reverse power flow from PVs to main source, which can lead to overvoltage in the distribution line. To mitigate this problem, it is proposed to install D-SCs close to pole transformer of the distribution line. A D-SC is a series compensator that can imitate characteristic of negative resistance and reactance, while reverse power flow occurs in distribution line. This is carried out by injecting active and reactive power to the distribution line through voltage injection. Providing active power for the D-SC is done by a bidirectional rectifier which is connected to the secondary side of a pole transformer. The effectiveness of the proposed method is achieved by the improvement of voltage profile with small capacity of D-SC and bidirectional rectifier. Theoretical analysis is discussed and simulation results are shown to verify the proposed method. Copyright © 2009 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. [source]

    Modelling of photonic bandgap devices by the leaky mode propagation method

    INTERNATIONAL JOURNAL OF NUMERICAL MODELLING: ELECTRONIC NETWORKS, DEVICES AND FIELDS, Issue 3 2003
    Agostino Giorgio
    Abstract Main modelling approaches used for investigating the Photonic bandgap (PBG) devices are reviewed. In particular, the model based on Leaky Mode Propagation (LMP) method is described. A complete analysis of the propagation characteristics, including the determination of modal propagation constants, electromagnetic field harmonics and total field distribution, transmission and reflection coefficients, total forward and backward power flow in the structure, guided and radiated power, and total losses, can be carried out by a computer program based on the LMP approach. The numerical results have been validated by comparisons with those obtained by using other more complex and expensive models. The new model shows some significant advantages in terms of very low computational time, absence of any a priori theoretical assumptions and approximations, capability of simulating the actual physical behaviour of the device and fast determination of the bandgap position.Copyright © 2003 John Wiley & Sons, Ltd. [source]