S. A. Y. Sabir

Bio: S. A. Y. Sabir is an academic researcher from Hydro One. The author has contributed to research in topics: AC power & Dynamic load testing. The author has an hindex of 1, co-authored 1 publications receiving 91 citations.

Dynamic Load Models Derived from Data Acquired During System Transients

Abstract: For several years power system load responses have been recorded during system transients by means of a remote data acquisition system developed by Ontario Hydro. Using these data, models for the loads are developed in the paper and parameters for the models are obtained. Conventional static load models are shown to represent adequately the characteristics of a residential/commercial feeder load. For large rotating industrial loads two models are developed. The first is a transfer function model which relates the small signal power and reactive power outputs to input changes in voltage and frequency. The second is an induction motor model with shunt static load. Recorded voltage is considered as an input to the model and the output real and reactive power are compared with the measured output. The weighted squared error between the measured output and the model output is minimized by obtaining optimum model parameters. Recorded and simulated responses of the paper mill loads are compared.

Load modeling for power flow and transient stability computer studies

Abstract: A novel method is presented for preparing load models for power flow and stability studies. The LOADSYN load model synthesis software package transforms data on load class mix, composition, and characteristics into the form required for commonly used flow and transient stability simulation programs. Typical default data have been developed for load composition and characteristics. The load-modeling techniques used in this software and results of initial testing are described. Significant improvements in simulation accuracy are demonstrated. >

Ramp-rate limits in unit commitment and economic dispatch incorporating rotor fatigue effect

Abstract: In this study, a rigorous mathematical method is proposed for dealing with the ramp-rate limits in unit commitment and the rotor fatigue effect in economic dispatch An iterative procedure is employed to coordinate the unit commitment and the power dispatch for obtaining an economical solution within a reasonable time The Lagrangian relaxation method is used to generate the unit commitment schedule with relaxed power balance constraints A network model is adopted to represent the dynamic process of operating a unit over the entire study time span, as the required unit commitment schedule can be achieved by searching for the shortest path in the network In order to find the global optimal solution for the economic dispatch problem within personal computer resources, a piecewise linear model is used for thermal units Furthermore, linear programming is used in optimizing the benefits of ramping the units, with low operating cost against the cost of shortening the service life of the turbine rotor In this regard, linear programming is used to dispatch the power generation among committed units by considering a ramping penalty for the fatigue effect in rotor shafts, while preserving the operational constraints of the system as well as the generating units >

Load modelling in studies of power system damping

Abstract: This paper considers the significance of load voltage dynamics in studies of power system damping. A generic model of dynamic loads is used to investigate the influence of active and reactive power dynamics on the damping of oscillations in a multimachine power system. The interaction between the load and the power system is explored in terms of load and system transfer functions. It is shown that the power system transfer function is composed of a static part and a dynamic part. The static part is derived from the power flow Jacobian. The investigations indicate that load voltage dynamics can significantly influence the damping of modal oscillations. Static load models can give quite misleading predictions of damping when loads actually exhibit dynamic behaviour.

On dynamic load models for voltage stability studies

Abstract: Appropriate modelling of dynamic loads is of primary importance in voltage stability studies. The paper deals with the modelling of a load consisting of a static load plus an aggregate of induction motors. The behavior of three simplified models for such a load configuration is compared. The three models are (A) a generic nonlinear dynamic model of the first order as proposed by Karlsson and Hill, (B) a static exponential load plus a dynamic first-order model for the induction motors, and (C) a static exponential load plus a dynamic third-order model for the induction motors. A power system with a longitudinal structure is chosen as the case-study. It is shown that for the same perturbation (tripping of one of two high-voltage parallel lines) the simulation results are quite different from each other and, in certain cases, only the third-order dynamic model correctly predicts the voltage collapse phenomena at the load bus. An interpretation of the different behavior of the various models is given.