IEEE Transactions on Power Systems

The authors present a new methodology for frequency and duration (F&D) assessment in composite generation and transmission reliability evaluation. The F&D indices are obtained from a nonsequential Monte Carlo simulation scheme. Computational effort is reduced by using the Lagrange multipliers associated with the adequacy assessment of each state to identify the boundary wall between failure and su... View full abstract»

A static voltampere-reactive (VAr) compensator (SVC) model based on nodal analysis, is presented. The model is integrated in the electromagnetic transients program (EMTP) with minimal interface error and by taking into account initialization. The model is basically a generic compensator using thyristor controlled reactors. The models are modular to represent adequately compensators of different de... View full abstract»

The authors outline a practical adaptive fuel allocation approach. The approach uses pseudo fuel prices as decision variables. As a result, the fuel allocation decision can be conveniently implemented in system operation by using the pseudo fuel prices to dispatch generation. A lower pseudo price usually results in higher fuel consumption and a higher pseudo price usually results in lower fuel con... View full abstract»

The authors propose an interchange brokerage system based on an optimal power flow (OPF) solution using linear programming (LP). Interchange brokering schedules power imports and exports between interconnected electric utilities to maximize profits for all participating parties and enhances the security of power systems. The data required for interchange brokerage systems are the amount of power a... View full abstract»

The authors present a knowledge- and algorithm-based approach to voltampere-reactive (VAr) planning in a transmission system. The VAr planning problem involves the determination of locations and sizes of new compensators considering contingencies and voltage collapse problems in a power system. An expert system model analyzes the operating conditions of a power system and suggests one or more of t... View full abstract»

The authors present a method for state estimation when the measurement set consists basically of node voltages and line currents. The key idea is that P- theta observability can be reached provided inequality constraints are added to the estimation process. These constraints simply state that P>or=0 for a generator bus and P View full abstract»

The authors propose a network partitioning algorithm based on the electrical distances among the buses of a system, using a sparse eigenvalue-based approach. The technique clusters interdependent buses together while weakly connected buses are placed in different clusters. The partitioning technique is independent of the system's operating condition. Small- and medium-sized power systems have been... View full abstract»

The authors address the problem of determining the maximum amount of active and reactive unserved load demand that can be connected to each bus in an electric power system without violation of its operating constraints. This maximal load demand allocation problem, which is associated with each electrical island of a power system operating in a restorative state, is formulated as a mixed nonlinear-... View full abstract»

A nonlinear control strategy to improve the steady-state stability of a weak AC/DC power system is presented. The approach is based on the extension of feedback linearization techniques to nonlinear descriptor system models. This method produces a nonlinear control strategy which is capable of enhancing system performance for various system operating conditions. The control law is determined and s... View full abstract»

An iterative dynamic programming method for solving the economic dispatch problems of a system of thermal generating units including transmission line losses is presented along with a clear explanation of modifying generator cost functions during each iteration. A zoom feature is applied during the iterative process in order to converge to the economic dispatch solution with low computer time and ... View full abstract»

The author develops a theoretically robust and computationally efficient distributed state estimator to solve the weighted least square state estimation problem by using distributed computation. This distributed state estimator is used in decentralized control and executes in a data communication network that is assumed to be topologically the same as and physically in parallel with the power netw... View full abstract»

The Chubu Electric Power Company (CEPCO) has developed the distribution automation system (DAS) by using minicomputers which monitor and control large and complex distribution networks with maximum reliability and promptness. A significant curtailment of the restoration operation time due to the occurrence of faults is expected by the introduction of the DAS. The authors introduce the DAS that was... View full abstract»

The development of a computer program far calculation of geomagnetically induced current (GIC) and a GIC power system model for the Pennsylvania-New Jersey-Maryland Interconnection (PJM) is described. Results of GIC for three different ionospheric source configurations are shown. A new method is presented for estimating GIC in unmetered parts of the system based on a few measurements and precalcul... View full abstract»

The main idea behind FACTS (flexible AC transmission system) is to use network parameters as controls to direct flow, thus eliminating problems caused by unwanted loop or parallel flows. The authors present a methodology for the representation of FACTS device such as phase shifters and series compensations in optimal power flow models. The proposed approach is based on, mathematical decomposition ... View full abstract»

The authors develop an efficient, recursive algorithm for determining the economic power dispatch of thermal generators within the unit commitment environment. The algorithm uses the equal incremental fuel cost criterion as its basis. In the algorithm, the fuel cost functions of the thermal generators are modeled by quadratic polynomials and the transmission losses are discounted. A method for inc... View full abstract»

The authors describe a model for calculating the spot price of electricity of a typical electric power system. The model combines economic dispatch calculations with loadflow and customer response functions in a Monte Carlo simulation model. The model contributes to the implementation of spot prices by providing a practical means of evaluating the spot price of a typical electric power system. It ... View full abstract»

The authors present a thermal unit commitment method for interconnected multiarea power systems. The method is a natural extension of the commitment utilization factor (CUF)-based single-area unit commitment method. CUF is extended to reflect the impact of multiarea transmission interconnection constraints on the utilization efficiency of committing a candidate unit at a given priority position. T... View full abstract»

The authors investigate the voltage stability problem based on singular perturbation theory. Possible voltage instability patterns are classified into four types (I, II-1, II-2S, and II-2D) according to the mechanism causing voltage instability. Several features of each type of instability are studied as well as their analysis methods. Voltage instability tends to begin with type I and then leads ... View full abstract»

The author presents a systematic approach to: (1) selecting the candidate lines on which an implementation of a dynamic thermal line rating (DTLR) system will have the biggest return; and (2) determining the economic value of this undertaking. To develop this approach, information about contingently overloaded lines, which have the biggest impact on the penalty for off-cost generation, and about i... View full abstract»

The authors present a fast and efficient technique for solving the power system state estimation problem using linear programming (LP). The dual formulation of the original problem is described. This formulation improves the solution time significantly. Four LP state estimators are presented and test results on the IEEE 30, 57, and 118 bus standard systems are included. Both the full and decoupled... View full abstract»

An attempt is made to define the state of the art and identify the most fertile grounds for future research in parallel processing as applied to power system computation. The analysis is confined to examining the application of parallel computers to specific power system problems. The state of the art is summarized in an attempt to capture the developing approach of matching algorithms to architec... View full abstract»

A heuristic approach to power system generation scheduling is discussed. The proposed short-term unit commitment employs a multistage neural network expert system approach to achieve real-time processing results. The operating constraints are presented as, heuristic rules in the system where a feasible solution is obtained through inference. The neural networks are used at the preprocessor and pos... View full abstract»

An adaptive scheme is proposed for determining the amount of load to be shed by underfrequency relays based on the observed initial slope of the frequency deviation. following the system separation. This initial slope contains all the information required to estimate that size of the step change in load caused by the system separation and to forecast the depth and even the approximate time of the ... View full abstract»

The authors introduced a new approach to estimate life distributions at nominal conditions from the results of accelerated life testing of electrical insulating materials. A very general family of probability distributions is introduced, and a best fit member of this family is used to represent life data at each stress level. Nonlinear optimization techniques are applied in conjunction with linear... View full abstract»

The authors present a new technique for extracting power system modes contained in a recorded time signal. The technique is based on spectral analysis and uses the Z-transform identification algorithm of Corinthios. It permits identification of the damping factor and the frequency of the modal signal components and it is computationally attractive due to efficient fast Fourier transform algorithms... View full abstract»