Computer Modeling of Rotating Machines

Modeling and simulating rotating machines in power systems under various disturbances are important not only because some disturbances can cause severe damage to the machines, but also because responses of the machines can affect system stability, safety, and other fundamental requirements for systems to remain in normal operation. Basically, there are two types of disturbances to rotating machines from disturbance frequency point of view. One type of disturbances is in relatively low frequency, such as system short-circuit faults, and generation and load impacts; and the other type of disturbances is in high frequency, typically including voltage and current surges generated from fast speed interruption device trips, and lightning strikes induced travelling waves. Due to frequency ranges, special models are required for different types of disturbances in order to accurately study machines behavior during the transients. This chapter describes two popular computer models for rotating machine transient studies in lower frequency range and high frequency range respectively. Detailed model equations as well as solution techniques are discussed for each of the model.