Reactive Power Planning (RPP) is one of the most complex problems of power systems.RPP utilizes the existing reactive power sources judiciously while planning suitable location and size of VAR compensation to be installed in a system to meet the requirements of future load increase to keep a reasonable voltage profile under normal condition and contingency states. RPP requires the simultaneous minimization of two objective functions. The first objective deals with the minimization of operation cost by reducing real power loss and improving the voltage profile. In this Book Fast Voltage Stability Index (FVSI) has been used to identify the weak buses for Reactive Power Planning. The outcome confirmed significant decrease in system losses and enhancement of voltage magnitude with the use of FVSI. The test and justification of the proposed algorithm are conducted on IEEE 30-bus system and 72-bus Indian system. Recently RPO problem is formulated as Multi-Objective Optimization (MOO) problem.