F. D'hulster, K. Stockman, J. Desmet, and R. Belmans (Belgium)
power quality analysis, voltage dips,undervoltage relay, modeling.
This paper proposes a dynamic model for the behavior of
an AC undervoltage protection relay during voltage dips.
The behavior is expressed by means of standardized
voltage tolerance curves and highly depends on the point
on-wave (phase angle) of the dip initiation. Using the
model, it can be explained that AC undervoltage relays
are much more sensitive to voltage dips of e.g. 50% Urated
than to short interruptions (0% Urated), caused by the
magnetic behavior. The model takes into account the
electrical, magnetic and mechanical system equations. An
experimental set-up with a programmable power source
as dipgenerator is build to validate the model. Finally, a
complete weaving machine is represented to analyze the
influence towards voltage dip immunity by adding an
undervoltage protection relay.