Starting Transients of Saturated Induction Motors with Series Capacitors on the Supply

The paper derives the equations to Simulate the transient behavior of an induction motor for large changes in currents and speed, taking into account the airgap flux saturation. The potentially unstable behavior during the starting of a series compensated induction motor is analised using these equations and results of the transients in stator current, terminal voltage, speed and electromagnetic torque are shown. The effect of a damping resistor in reducing the refered instability and in allowing a successful starting is verified not only by simulation of the transients in the time domain, but also through the small signal stability analysis of the machine's equations linearized around an operating point in the starting slip range.