A. M. Sasson

Bio: A. M. Sasson is an academic researcher from American Electric Power. The author has contributed to research in topics: Power-flow study & Electric power system. The author has an hindex of 17, co-authored 21 publications receiving 1645 citations. Previous affiliations of A. M. Sasson include Imperial College London & Monterrey Institute of Technology and Higher Education.

Investigation of the load-flow problem

Abstract: A mesh approach is developed for the formulation of the network equations in load-flow analysis. It is shown to converge at least as fast as the usual methods using the nodal-impedance matrix. A hybrid approach is then developed, using a combination of an impedance-matrix method and a nodal-admittance-matrix method. The hybrid exhibits very fast convergence, and is the most powerful method encountered by the authors. It needs no optimum acceleration, and the number of iterations appear to be independent of system size and configuration. Finally, an investigation into the choice of an optimum swing/reference bus produced the only reliable criterion known to the authors.

Stochastic load flows

Abstract: The load flow study has been at the center of studies made for designing and operating power systems for many years. It is well known that forecasted data used in load flow studies contain errors that affect the solution, as can be evidenced by running many cases perturbing the input data. This paper presents a method for calculating the effect of the propagation of data inaccuracies through the load flow calculations, thus obtaining a range of values for each output quantity that, to a high degree of probability, encloses the operating conditions of the system. The method is efficient and can be added to any existing load flow program. Results of cases run on the AEP system are included.

Nonlinear Programming Solutions for Load-Flow, Minimum-Loss, and Economic Dispatching Problems

Abstract: A unified approach to load-flow, minimum-loss, and economic dispatching problems is presented. A load-flow solution is shown to coincide with the minimum of a function of the power system equations. An unconstrained minimization method, developed by Fletcher-Powell, is used to solve the load-flow problem. The method always finds a solution or indicates the nonexistence of a solution. Its performance is highly independent of the reference- slack bus position and requires no acceleration factors. Several constrained minimization techniques that solve the minimum-loss and economic dispatching problems are investigated. These include the Fiacco-McCormick, Lootsma, and Zangwill methods. The technique finally recommended is shown to be an extension of the method used to solve the load-flow problem. The approved IEEE test systems, and other systems whose response to conventional methods was known, have been solved.

A Fast and Reliable State Estimation Algorithm for AEP's New Control Center

Abstract: This paper presents an evaluation of some previously proposed and newly developed state estimation algorithms. One new algorithm, which employs a constant, decoupled gain matrix and certain other simplifying approximations, is shown to be clearly superior to the other methods considered; accordingly this algorithm has been chosen for use in AEP's new control center. The selected algorithm is fast, reliable and can process a measurement set consisting of line flows, bus injections and voltage magnitudes. Test results are given for several real networks and some standard IEEE test systems (having as many as 460 buses and R/X ratios ranging from 0.1 to 2). The network conditions used in the tests range from light load to severe contingencies with low voltages and large phase angles. A wide variety of practical and hypothetical measurement sets are considered.

An Automatic Contingency Selection Method for On-Line Security Analysis

Abstract: An efficient and reliable method for automatic contingency selection is presented. The method is based on the prediction of the value of a system wide performance index for each transmission line outage and the subsequent ranking of the severity of the outages according to the predicted values of the performance index.

Synchronized Phasor Measurements and Their Applications

Abstract: Phasor Measurement Techniques.- Phasor Estimation of Nominal Frequency Inputs.- Phasor Estimation at Off-Nominal Frequency Inputs.- Frequency Estimation.- Phasor Measurement Units and Phasor Data Concentrators.- Transient Response of Phasor Measurement Units.- Phasor Measurement Applications.- State Estimation.- Control with Phasor Feedback.- Protection Systems with Phasor Inputs.- Electromechanical Wave Propagation.

A Practical Method for the Direct Analysis of Transient Stability

Abstract: This paper describes the development and evaluation of an analytical method for the direct determination of transient stability. The method developed is based on the analysis of transient energy and accounts for the nature of the system disturbance as well as for the effects of transfer conductances onsystenmbehavior. It has been evaluated on a 10 generator 39 bus system and on a 20 generator 118 bus system. The method predicts critical clearing times for first swing transient stability which agree very closely with the results of simulations.

A review of selected optimal power flow literature to 1993. I. Nonlinear and quadratic programming approaches

Abstract: The paper presents a review of literature on optimal power flow tracing progress in this area over from 1962-93. Part I deals with the application of nonlinear and quadratic programming.

Optimal Power Flow By Newton Approach

Abstract: The classical optimal power flow problem with a nonseparable objective function can be solved by an explicit Newton approach. Efficient, robust solutions can be obtained for problems of any practical size or kind. Solution effort is approximately proportional to network size, and is relatively independent of the number of controls or binding inequalities. The key idea is a direct simultaneous solution for all of the unknowns in the Lagrangian function on each iteration. Each iteration minimizes a quadratic approximation of the Lagrangian. For any given set of binding constraints the process converges to the Kuhn-Tucker conditions in a few iterations. The challenge in algorithm development is to efficiently identify the binding inequalities.

Electric power system state estimation

Abstract: This paper discusses the state of the art in electric power system state estimation. Within energy management systems, state estimation is a key function for building a network real-time model. A real-time model is a quasi-static mathematical representation of the current conditions in an interconnected power network. This model is extracted at intervals from snapshots of real-time measurements (both analog and status). The new modeling needs associated with the introduction of new control devices and the changes induced by emerging energy markets are making state estimation and its related functions more important than ever.