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Asynchronous or induction motors are commonly employed in industrial applications. Their precise accelerating or starting time is needed for setting their overcurrent protection devices against heating and for assessing power quality of electric utility distribution power system. The accelerating time is usually determined from a tedious time-domain dynamic simulation with commercial software tools, which basically require a full knowledge of the motor's equivalent parameters. Often these parameters are not readily available to the end-users while other technical information is. Thus, this paper presents a novel analytical approach to calculate the motor accelerating time using standard technical data. The required speed-torque curve of induction motors is directly determined from the manufacturer-provided information, instead of requiring the conventional equivalent-circuit parameters. Accuracy of the proposed technique is validated by comparing the calculated accelerating times against those from time-domain dynamic simulations using a full fifth-order model of induction motor: the results mostly agree in a satisfactory manner. [ABSTRACT FROM AUTHOR]

Vast majority of already‐installed grid‐connected wind turbines is fixed‐speed wind generators (FSWGs). Their initialisations for power‐system dynamic simulations are mostly performed using conventional power‐flow approach, causing an unavoidable reactive‐power discrepancy between power‐flow result and generator dynamic model. To eliminate this problem, unified Newton–Raphson (NR) power‐flow approach together with wind‐turbine aerodynamic power coefficient is applied for accurate initialisation of the FSWG under passive‐stall regulation. However, FSWG initialisations relating to two other active‐stall and active‐pitch regulations under the same approach have not yet been addressed. Therefore, in this study, the unified power‐flow approach is straightforwardly extended to yield efficient and precise dynamic initialisations of active‐stall‐ and active‐pitch‐regulated FSWGs. In the proposed model, variables of generators and wind turbines are fully solved all together with the power coefficients. The obtained power‐flow result is compared with the published result for model verification. Efficiency of the extended algorithm is demonstrated using IEEE‐300bus and 118bus networks with large groups of wind power plants. The simulation results reveal that the extended algorithm not only gives precise steady‐state initialisation of the FSWGs but also retains NR quadratic convergence characteristics. [ABSTRACT FROM AUTHOR]