الفهرس 
Power System Stability ProblemOnly 14 pages are availabe for public view
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Abstract
Voltage stability problems are now taking much more
consideration due to its importance to the electric utility
industry and due to the major consequences related to the
voltage instability. The energy function technique has been
previously applied to investigate the voltage stability of power
systems for constant power load model only.
This research deals with the effect of load
modeling( constant impedance, constant current and constant
power load models) on voltage stability studies. The proposed
formulation has been applied to both a test system and Ontario-
Hydro real power system.
For the constant power load model, the gradual load
increase is followed by a decrease in the system voltage
stability until finally reaching the collapse point.
For higher constant impedance and constant current load
percentages, and especially constant impedance, the gradual
load increase is followed by a decrease in system stability until
reaching first a critical power level (maximum power).This
maximum power occurs at a voltage level not much lower than
the system nominal value.
Any further increase of load fails to raise the system
power beyond that critical power level (max. power). On the
contrary, the system total power starts to decrease due to the
dependency of such loads on the voltage levels, which
continues dropping until reaching the collapse point at a power
level very much lower than the maximum power.
The ANN methodology is also applied to the voltage
stability problem, a suitable ANN structure has been selected
and trained. The ANN shows matching results to those obtained
by the energy function technique.