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This paper presents an optimal routing algorithm (ORA) for minimizing power loss and at the same time maximizing the voltage stability in radial power systems. In the proposed ORA, a voltage stability index (VSI) for real-time assessment is introduced based on the conventional critical transmission path framework. In addition, the algorithm can automatically detect the critical transmission paths that will result in voltage collapse when additional real or reactive loads are added. To implement effective ORA, an improved branch exchange (IBE) method has been developed based on a loss calculation index and tie-branch power flows that is suited for real-time applications. The proposed algorithm has been tested in the IEEE 32- and 69-bus systems as well as in a large-scale Korea Electric Power Company 148-bus system to show its effectiveness and efficiency. Index Terms--Branch exchange, combinatorial optimization, loss minimization, optimal routing algorithm (ORA), radial power system, voltage stability index (VSI).

This paper presents a new approach to economic dispatch (ED) problems with nonsmooth cost functions using a particle swarm optimization (PSO) technique. The practical ED problems have nonsmooth cost functions with equality and inequality constraints that make the problem of finding the global optimum difficult using any mathematical approaches. In this paper, a modified PSO (MPSO) mechanism is suggested to deal with the equality and inequality constraints in the ED problems. A constraint treatment mechanism is devised in such a way that the dynamic process inherent in the conventional PSO is preserved. Moreover, a dynamic search-space reduction strategy is devised to accelerate the optimization process. To show its efficiency and effectiveness, the proposed MPSO is applied to test ED problems, one with smooth cost functions and others with nonsmooth cost functions considering valve-point effects and multi-fuel problems. The results of the MPSO are compared with the results of conventional numerical methods, Tabu search method, evolutionary programming approaches, genetic algorithm, and modified Hopfield neural network approaches. Index Terms--Constrained optimization, economic dispatch (ED), nonsmooth optimization, particle swarm optimization (PSO).

In this paper, a new approach to maintenance scheduling of generating units (MSU) in competitive electricity markets is presented. The main contribution of this study can be focused on modeling a game-theoretic framework for the MSU problem to analyze strategic behaviors of generating companies (Gencos). The MSU problem is formulated as a dynamic noncooperative game with complete information. The player corresponds to the profit maximizing individual Genco, and the payoff of each player is defined as the profit from the energy auction market. The optimal strategy profile is defined by the Nash equilibrium of the game. Numerical results for two-Genco systems are used to demonstrate the basic ideas of the proposed scheme, and large-scale IEEE reliability test systems are also considered to show the applicability of the proposed framework. The results obtained indicate that maintenance schedule can be one of the crucial strategic behaviors whereby Genco maximizes their profit in a competitive market environment. Index Terms--Competitive market, dynamic noncooperative game, maintenance scheduling of generating unit, maintenance strategy, Nash equilibrium.

This paper proposes an analytical approach for allocating transmission transaction costs among users in transmission services. The proposed method allocates the transaction costs over the participants proportional to the ratio of incremental power flow caused by each participant and the total power flows on a designated transmission line. To determine the individual participant's impact on the transmission power flows, the Line Utilization Factors (LUFs) of each participant are developed from a set of power flow equations. In the developed framework, one can directly evaluate the sensitivity of the flow on a line with respect to power generation at all buses. Although the developed allocation nile is very similar to the existing MW-mile method, especially to the Modulus Method, it does not require to perform load flow analysis whenever each wheeling transaction is exercised. The main advantage of the developed method lies in its capability to consider multiple wheeling transactions simultaneously. Keywords: Transmission Transaction Costs, Line Utilization Factors, MW-mile Method, Multiple Wheeling Transactions

This paper presents a development of an improved genetic algorithm (IGA) and its application to a least-cost generation expansion planning (GEP) problem. Least-cost GEP problem is concerned with a highly constrained nonlinear dynamic optimization problem that can only be fully solved by complete enumeration, a process which is computationally impossible in a real-world GEP problem. In this paper, an improved genetic algorithm incorporating a stochastic crossover technique and an artificial initial population scheme is developed to provide a faster search mechanism. The main advantage of the IGA approach is that the 'curse of dimensionality' and a local optimal trap inherent in mathematical programming methods can be simultaneously overcome. The IGA approach is applied to two test systems, one with 15 existing power plants, 5 types of candidate plants and a 14-year planning period, and the other, a practical long-term system with a 24-year planning period. Index Terms--Generation expansion planning, genetic algorithm, global optimization, improved genetic algorithm.

This paper presents a game theory application for analyzing power transactions in a deregulated energy marketplace such as PoolCo, where participants, especially, generating entities, maximize their net profits through optimal bidding strategies (i.e., bidding prices and bidding generations). In this paper, the electricity market for power transactions is modeled as a noncooperative game with complete information, where the solution is determined in a continuous strategy domain having recourse to the Nash equilibrium idea. In order to provide more apprehensible analysis, we suggest a new hybrid solution approach employing a 2-dimensional graphical approach as well as an analytical method. Finally, the proposed approach is demonstrated on a sample power system. Index Terms--Continuous strategy, deregulation, game theory, PoolCo model, spot market.