FAULT DURATION FOR VOLTAGE INSTABILITY AND VOLTAGE COLLAPSE INITIATION AS INFLUENCED BY DURATION OF COLD INRUSH CURRENT MAGNITUDES

The occurrence of voltage instabilities or voltage collapses depend on the duration of the

persistence of the fault and on the type of fault, some faults lead to voltage instabilities, others

lead to voltage collapse. Evaluation of fault durations causing occurrence of voltage instabilities

or collapse is the main goal of this paper. This paper searches for the effect of peak inrush current

and its duration periods initiation of voltage instability, with lagging and leading load power

factors at certain loads buses. Also, this paper searches about the fault duration required for

voltage collapse. The influence of the cold inrush current on this fault duration is studied. .Form

several tedious trials, it is noticed that, the phenomena of voltage collapse can be occurred with

some line opening in the studied system.