The influence of overcurrent and undervoltage protection settings on ASD sensitivity to voltage sags and short interruptions

This paper analyses sensitivity of adjustable speed drives (ASDs) to voltage sags and short interruptions. Voltage tolerance curves for three following different types of control of ASDs are compared and discussed: V-Hz control, field-oriented control and direct torque control. The obtained results are based on computer simulations with developed drive models, in which overcurrent and undervoltage drive protection systems are applied first individually and separately from each other, and then simultaneously.