This thesis aims to investigate AGC in a conventional regulated power system and a deregulated power system with the integration of Solar PV, Battery Energy Storage System (BESS), Super magnetic Energy Storage (SMES) and Static Synchronous Compensator (STATCOM). The linear time invariant models of Solar PV, BESS, SMES and STATCOM have been implemented in a two area power system for improving transient stability of the system. The average switching models of the active and reactive power devices have been presented to highlight the output current and power dynamics of the devices. With the availability of the active and reactive power compensation devices, the study extends to the optimal location and sizing of the devices which has not been attempted so far.