An improved simulation algorithm for the determination of motor starting transients

The effects of starting large motors have long been of interest to power engineers. A significant amount of research has been conducted in this area, culminating in the development of a variety of computer algorithms designed to predict the effects of the motor starting transients. A review of some of the computer-based techniques is provided as background material in this paper. An improved simulation algorithm for motor starting analyses has been developed based on a combined time- and frequency-domain simulation technique. The complete differential equation-based dq0 induction motor model is used to represent the behavior of the induction machine. The complete model is chosen to allow the direct inclusion of models for typical motor starters/controllers and to avoid inaccuracies associated with reduced-order models. Frequency-domain techniques are used to formulate a multi-phase industrial power distribution system model. A least-squares estimation technique developed for digital relaying applications is used as an “interface” between the time-domain differential equation solutions and the frequency-domain network solutions. Simulation results obtained using the presented algorithm are accurate relative to the ElectroMagnetics Transients Program but can be obtained in a much shorter time period