Abstract-This Paper deals with the problem of voltage instability that leads in some cases to voltage collapse and complete blackouts. Voltage instability, being the absence of voltage stability, results in progressive voltage decrease (or increase). A power system at a given operating state and subject to a given disturbance undergoes voltage collapse if the post-disturbance equilibrium voltage is below acceptable limits. Voltage collapse may be total or partial blackout. Many major blackouts throughout the world have been directly associated to this phenomenon, e.g. in France, Italy, Japan, Great Britain, USA, etc. The analysis of this problem shows that the major causes is the system’s inability to meet the reactive power demands. The main objective of this work is to find the most favorite methods to assure the security of the system in terms of voltage stability.[2] In most case studies, using of one remedial action is not enough to solve the voltage instability problem. This paper declares that the usage of combined remedial actions, specially during the peak load hours is a must solution in most cases. Also it is declared that the usage of normal capacitors to add reactive power together with the other suggested methods helps much as being a cheap tool. It is known that the improvement of voltage levels on a power system reduces the losses. In the present case, specially at peak load, it is gained that the same energy demand could be fulfilled with less power generation. In addition to securing the voltage levels on a power system, a feasible return is achieved.