IEEE Transactions on Energy Conversion

In this paper, the self and mutual inductances of an exciter for a genset alternator are estimated for different rotor angular positions by the use of finite-element (FE) techniques. These inductances, which are described by complex functions, are measured using a stationary test and compared with calculated values. A real-time computer model for the exciter, the load and the diode bridge mounted on the rotor is then proposed, and a sample of performance prediction and measurement for a specific transient condition of the exciter is presented here as confirmation of the method. The model thus validated is ultimately to be included in the evolving total system model used for simulation of genset transient and steady-state performance.

In this paper, a novel evolutionary algorithm-based approach to optimal design of multimachine power-system stabilizers (PSSs) is proposed. The proposed approach employs a particle-swarm-optimization (PSO) technique to search for optimal settings of PSS parameters. Two eigenvalue-based objective functions to enhance system damping of electromechanical modes are considered. The robustness of the proposed approach to the initial guess is demonstrated. The performance of the proposed PSO-based PSS (PSOPSS) under different disturbances, loading conditions, and system configurations is tested and examined for different multimachine power systems. Eigenvalue analysis and nonlinear simulation results show the effectiveness of the proposed PSOPSSs to damp out the local and interarea modes of oscillations and work effectively over a wide range of loading conditions and system configurations. In addition, the potential and superiority of the proposed approach over the conventional approaches is demonstrated.

Full-load testing of large induction machines is constrained by the limitations in the power-supply and loading equipment of the manufacturer's facilities, resulting in costly set up time. A new synthetic loading method is proposed based on a bang-bang phase control strategy. The rated power oscillation created is routed to an auxiliary system and the source hydro has to provide only the total losses of the system, without seeing the excessive power swings observed in other synthetic loading techniques. In this technique, only induction machines are used which would enable motor manufacturers to build the test rig in-house. The control stage is very simple to implement and requires only unregulated DC supplies for the excitation windings. The method is suitable for any induction machine and does not requires any set up time. It is possible to strictly maintain constant DEFINE RMS voltage and current at rated values for the duration of the heat runs.

A substantial proportion of induction motor faults are eccentricity related. In practice, static and dynamic eccentricities happen to exist together. With this point in mind, an analytical approach to evaluate the performance of a three-phase induction motor under mixed eccentric conditions is presented in this paper. A clear and step-by-step theoretical analysis, explaining completely the presence of certain harmonics in the line-current spectrum in the presence of eccentricity, is discussed. More importantly, it is shown for the first time that a link exists between the low- and high-frequency elements of these harmonics. It is also shown that these high-frequency components are not very strong in all types of machine. These results will be useful in generating rules and laws to formulate online tools for machine condition monitoring. Finite-element results to substantiate the inductance values used in the simulation are also included. The analysis is validated by the line-current spectrum of the eccentric machine obtained through simulation using the modified winding-function approach (MWFA) and experimentation.

A common approximation used in the analysis of power systems is the neglect of the dynamic saliency in synchronous machines. In this paper, it is shown that eliminating the error associated with neglecting dynamic saliency can be accomplished with the addition of a singular perturbation(s) into the machine model. By considering the elimination of error in such a way, singular-perturbation-based model-order-reduction techniques are used to derive detailed- and reduced-order models of synchronous machines where dynamic saliency is eliminated with zero error and no added numerical cost.

Considering motional effects in the steady-state finite-element simulation of single-phase induction machines inevitably requires a transient approach. The resulting computation time seriously hampers the application of finite elements within technical designs. In this paper, time-harmonic finite-element simulation, as commonly applied to the three-phase induction machine model, is also enabled for single-phase motors by decomposing the air-gap field in two revolving fields in the opposite direction. The advantages and drawbacks of the novel approach are illustrated by a benchmark model. Issues such as ferromagnetic saturation, external circuit coupling, adaptive mesh refinement, and torque computation are addressed. The method is used to simulate a capacitor start/run motor.