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John W Simpsonporco - One of the best experts on this subject based on the ideXlab platform.

  • a theory of solvability for lossless Power Flow equations part i fixed point Power Flow
    IEEE Transactions on Control of Network Systems, 2018
    Co-Authors: John W Simpsonporco
    Abstract:

    This two-part paper details a theory of solvability for the Power Flow equations in lossless Power networks. In Part I, we derive a new formulation of the lossless Power Flow equations, which we call the fixed-point Power Flow. The model is stated for both meshed and radial networks and is parameterized by several graph-theoretic matrices—the Power network stiffness matrices—which quantify the internal coupling strength of the network. The model leads immediately to an explicit approximation of the high-voltage Power Flow Solution. For standard test cases, we find that iterates of the fixed-point Power Flow converge rapidly to the high-voltage Power Flow Solution, with the approximate Solution yielding accurate predictions near base-case loading. In Part II, we leverage the fixed-point Power Flow to study Power Flow solvability. For radial networks, we derive conditions guaranteeing the existence and uniqueness of a high-voltage Power Flow Solution. These conditions properly generalize the textbook two-bus system results, and imply exponential convergence of the fixed-point Power Flow iteration.

  • a theory of solvability for lossless Power Flow equations part ii conditions for radial networks
    IEEE Transactions on Control of Network Systems, 2018
    Co-Authors: John W Simpsonporco
    Abstract:

    This two-part paper details a theory of solvability for the Power Flow equations in lossless Power networks. In Part I, we derived a new formulation of the lossless Power Flow equations, which we call the fixed-point Power Flow. The model is parameterized by several graph-theoretic matrices—the Power network stiffness matrices—which quantify the internal coupling strength of the network. In Part II, we leverage the fixed-point Power Flow to study Power Flow solvability. For radial networks, we derive parametric conditions which guarantee the existence and uniqueness of a high-voltage Power Flow Solution, and construct examples for which the conditions are also necessary. The conditions imply convergence of the fixed-point Power Flow iteration, and unify recent results on the solvability of decoupled Power Flow. These results directly generalize the textbook two-bus system results, and provide new insights into how the structure and parameters of the grid influence Power Flow solvability.

  • high voltage Solution in radial Power networks existence properties and equivalent algorithms
    IEEE Control Systems Letters, 2017
    Co-Authors: Krishnamurthy Dvijotham, Enrique Mallada, John W Simpsonporco
    Abstract:

    The ac Power Flow equations describe the steady-state behavior of the Power grid. While many algorithms have been developed to compute Solutions to the Power Flow equations, few theoretical results are available characterizing when such Solutions exist, or when these algorithms can be guaranteed to converge. In this letter, we derive necessary and sufficient conditions for the existence and uniqueness of a Power Flow Solution in balanced radial distribution networks with homogeneous (uniform R/X ratio) transmission lines. We study three distinct Solution methods: 1) fixed point iterations; 2) convex relaxations; and 3) energy functions—we show that the three algorithms successfully find a Solution if and only if a Solution exists. Moreover, all three algorithms always find the unique high-voltage Solution to the Power Flow equations, the existence of which we formally establish. At this Solution, we prove that: 1) voltage magnitudes are increasing functions of the reactive Power injections; 2) the Solution is a continuous function of the injections; and 3) the Solution is the last one to vanish as the system is loaded past the feasibility boundary.

  • a theory of solvability for lossless Power Flow equations part ii conditions for radial networks
    arXiv: Optimization and Control, 2017
    Co-Authors: John W Simpsonporco
    Abstract:

    This two-part paper details a theory of solvability for the Power Flow equations in lossless Power networks. In Part I, we derived a new formulation of the lossless Power Flow equations, which we term the fixed-point Power Flow. The model is parameterized by several graph-theoretic matrices -- the Power network stiffness matrices -- which quantify the internal coupling strength of the network. In Part II, we leverage the fixed-point Power Flow to study Power Flow solvability. For radial networks, we derive parametric conditions which guarantee the existence and uniqueness of a high-voltage Power Flow Solution, and construct examples for which the conditions are also necessary. Our conditions (i) imply convergence of the fixed-point Power Flow iteration, (ii) unify and extend recent results on solvability of decoupled Power Flow, (iii) directly generalize the textbook two-bus system results, and (iv) provide new insights into how the structure and parameters of the grid influence Power Flow solvability.

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

  • security constrained optimal Power Flow Solution of wind thermal generation system using modified bacteria foraging algorithm
    Energy, 2015
    Co-Authors: Ambarish Panda, M Tripathy
    Abstract:

    Abstract In this work the variability of WP (wind Power) has been suitably modelled and incorporated with the thermal generating units. The goal is to operate the wind-thermal generation system in a cost effective manner while maintaining a voltage secure operation with reduction in system loss. These objectives have been formulated in an OPF (optimal Power Flow) framework. As the wind generation cost model is subjected to intermittent WP, the voltage security aspect is considered during both UE (under estimation) and OE (over estimation) of available WP. This is achieved by suitably incorporating shunt facts devices (STATCOM) to provide reactive Power ( Q ) support during UE scenario and maintaining a spinning reserve of thermal generators during OE scenario. To further utilize the Q -support, the DFIG (doubly fed induction generators) are used in the wind turbine. The combinations of optimum operational paradigms are obtained by optimizing the objective function with ACO (ant colony optimization) and MBFA (modified bacteria foraging algorithm). Finally, after performing several tests the superiority of MBFA optimized scenario over ACO is revealed so that the IEEE30-bus system operates in a voltage secured manner when subjected to N-1 contingencies.

  • optimal Power Flow Solution of wind integrated Power system using modified bacteria foraging algorithm
    International Journal of Electrical Power & Energy Systems, 2014
    Co-Authors: Ambarish Panda, M Tripathy
    Abstract:

    Owing to the intermittent nature of wind Flow, optimal Power Flow in a Power system with considerable wind energy penetration is a challenging issue. In this paper an OPF Solution is proposed for IEEE 30 bus Power system modified by replacing three conventional generators with equivalent wind energy conversion systems (WECS).The uncertain nature of wind Power has the risk of over or under estimating the capacity of available wind Power. This uncertainty has been suitably modeled and included in the OPF framework. Moreover, to justify the limitation of reactive Power generation capability of doubly fed induction generator based WECS during under estimation, additional cost component corresponding to external reactive Power (Q) generating sources has been added in the objective function. The scheduling problem of WECS integrated Power system is solved by formulating it as an optimization problem. Genetic algorithm and a modified bacteria foraging algorithm are employed separately to determine the optimal schedule. The optimal Solution obtained with a modified version of BFA has been found to give better results compared to GA. The results depict the impact of wind and thermal scheduling on total system cost and reiterate the need of additional support of reactive Power resources to maintain stable voltage profiles of the wind–thermal system.

Hugo Ambrizperez - One of the best experts on this subject based on the ideXlab platform.

  • a thyristor controlled series compensator model for the Power Flow Solution of practical Power networks
    IEEE Transactions on Power Systems, 2000
    Co-Authors: C R Fuerteesquivel, E Acha, Hugo Ambrizperez
    Abstract:

    A new and comprehensive load Flow model for the thyristor controlled series compensator (TCSC) is presented in this paper. In this model the state variable is the TCSC's firing angle, which is combined with the nodal voltage magnitudes and angles of the entire network in a single frame-of-reference for a unified iterative Solution through a Newton-Raphson method. Unlike TCSC models available in the open literature, this model takes account of the loop current that exists in the TCSC under both partial and full conduction operating modes. Also, the model takes proper care of the resonant points exhibited by the TCSC fundamental frequency impedance. The Newton-Raphson algorithm exhibits quadratic or near-quadratic convergence characteristics, regardless of the size of the network and the number of TCSC devices.

  • a comprehensive newton raphson upfc model for the quadratic Power Flow Solution of practical Power networks
    IEEE Transactions on Power Systems, 2000
    Co-Authors: C R Fuerteesquivel, E Acha, Hugo Ambrizperez
    Abstract:

    A new and comprehensive load Flow model for the unified Power Flow controller (UPFC) is presented in this paper. The model is incorporated into an existing Newton-Raphson load Flow algorithm. Unlike existing UPFC models available in open literature, it can be set to control active and reactive Powers and voltage magnitude in any combination or to control none of them. A set of analytical equations has been derived to provide good UPFC initial conditions. Hence, the algorithm exhibits quadratic or near-quadratic convergence characteristics. Suitable guidelines are suggested for an effective control coordination of two or more UPFCs operating in series or parallel arrangements. Test results are presented which demonstrate the effectiveness of the new model.

Thanatchai Kulworawanichpong - One of the best experts on this subject based on the ideXlab platform.

  • optimal Power Flow Solution using improved harmony search method
    Soft Computing, 2013
    Co-Authors: Nampetch Sinsuphan, Uthen Leeton, Thanatchai Kulworawanichpong
    Abstract:

    This paper describes the improved harmony search method (IHS) to solve optimal Power Flow (OPF) problems. The harmony search is one of meta-heuristic search methods inspired by the improvisation of musicians developed by Geem (2001) [23]. The proposed algorithm was tested with five standard IEEE test systems (6-bus, 14-bus, 30-bus, 57-bus and 118-bus test systems). The tests were divided into smooth and non-smooth fuel-cost cases. The comparisons among Solutions obtained by sequential quadratic programming (SQP), genetic algorithms (GA) and IHS were conducted. As revealed from the simulated results, the effectiveness of the IHS for solving OPF problems was confirmed.

  • Multi-Agent Based Optimal Power Flow Solution
    2012 Asia-Pacific Power and Energy Engineering Conference, 2012
    Co-Authors: Uthen Leeton, Thanatchai Kulworawanichpong
    Abstract:

    This paper describes multi-agent based optimal Power Flow Solution in which total production cost is used as the problem objective to be minimized. In this work, simulation of peer-to-peer device coordination has been developed using Java Agent Development (JADE) software package. JADE provides a FIPA-compliant agent platform and a package to develop multi-agent systems used in this paper. Six agent types are established. They are i) load agent ii) Power generating plants agent, iii) transformer tap-setting agent iv) reactive Power agent v) optimal load-Flow agent and vi) management agent. In this paper each agent has been modeled as an intelligent agent, which joins to a container to form the multi agent system for solving optimal Power Flow problems. In this paper, the standard IEEE 6-bus test Power system was employed. The results of this proposed system showed that the use of multi-agent systems enables possibility of applying optimal Power Flow in real-world applications.

  • simplified newton raphson Power Flow Solution method
    International Journal of Electrical Power & Energy Systems, 2010
    Co-Authors: Thanatchai Kulworawanichpong
    Abstract:

    Abstract This paper presents a simplified version of the well-known Newton–Raphson Power-Flow Solution method, which is based on the current balance principle to formulate a set of nonlinear equations. Although there exist several Powerful Power Flow solvers based on the standard Newton–Raphson (NR) method, their corresponding problem formulation is not simple due to the need for calculation of derivatives in their Jacobian matrix. The proposed method employs nonlinear current mismatch equations instead of the commonly-used Power mismatches to simplify overall equation complexity. Derivation of Jacobian matrix’s updating formulae is illustrated in comparison with those of the standard Newton–Raphson method. To demonstrate its use, a simple 3-bus Power system was selected as a numerical example. The effectiveness of the proposed method was examined by computer simulations through five test systems: (1) 5-bus test system, (2) 6-bus test system, (3) 24-bus IEEE test system, (4) 30-bus IEEE test system and (5) 57-bus IEEE test system. Its convergence and calculation time were observed carefully and compared with Solutions obtained by the standard NR Power Flow method. The results show that the proposed NR method spends less execution time than the standard method does with similar convergence characteristics.

Sydulu Maheswarapu - One of the best experts on this subject based on the ideXlab platform.

  • enhanced genetic algorithm based computation technique for multi objective optimal Power Flow Solution
    International Journal of Electrical Power & Energy Systems, 2010
    Co-Authors: Sailaja M Kumari, Sydulu Maheswarapu
    Abstract:

    Abstract Optimal Power Flow (OPF) is used for developing corrective strategies and to perform least cost dispatches. In order to guide the decision making of Power system operators a more robust and faster OPF algorithm is needed. OPF can be solved for minimum generation cost, that satisfies the Power balance equations and system constraints. But, cost based OPF Solutions usually result in unattractive system losses and voltage profiles. In the present paper the OPF problem is formulated as a multi-objective optimization problem, where optimal control settings for simultaneous minimization of fuel cost and loss, loss and voltage stability index, fuel cost and voltage stability index and finally fuel cost, loss and voltage stability index are obtained. The present paper combines a new Decoupled Quadratic Load Flow (DQLF) Solution with Enhanced Genetic Algorithm (EGA) to solve the OPF problem. A Strength Pareto Evolutionary Algorithm (SPEA) based approach with strongly dominated set of Solutions is used to form the pareto-optimal set. A hierarchical clustering technique is employed to limit the set of trade-off Solutions. Finally a fuzzy based approach is used to obtain the optimal Solution from the tradeoff curve. The proposed multi-objective evolutionary algorithm with EGA–DQLF model for OPF Solution determines diverse pareto optimal front in just 50 generations. IEEE 30 bus system is used to demonstrate the behavior of the proposed approach. The obtained final optimal Solution is compared with that obtained using Particle Swarm Optimization (PSO) and Fuzzy satisfaction maximization approach. The results using EGA–DQLF with SPEA approach show their superiority over PSO–Fuzzy approach.