The stability and security of power systems are of utmost importance to planning and operation engineers. As demand on grid resources increase, and contingency impacts on the interconnected power grids become more threatening/severe, real-time determination of power system operation and control is needed. This paper therefore develops an integrated strategy for handling the challenging problem of maintaining voltage stability for online applications in power engineering. The proposed method builds on recent advanced in the areas of real-time voltage stability monitoring and control. It is based on the use of real-time measurements via phasor measurement unit (PMU) technology. The design strategy will allow the real-time computation and controls, such as adjustments of voltage regulators or controllable series/shunt compensators, to arrest voltage instability at its onset.