The performance of an AC transmission line is an important factor that affects the performance of a power system because the transmission line consists of resistance, capacitance and inductance parameters that are distributed over its length. These parameters cause losses due to the reactive power component so the losses need to be reduced effectively, as a consequence, the performance can be highly increased. Therefore, in order to improve the efficiency, it is necessary to use an efficient solution that can provide reactive power compensation. The reactive power compensators form FACTS devices made of power electronic components which have been developed rapidly over the last decade. The paper studies characteristics of a generic transmission system , evaluation the power flow and hence determination the maximum power transfer possible. Also, to develop fundamental frequency model of a Static Series Synchronous Compensator (SSSC) and determine the best location and rating of the SSSC to maximise the utilisation of the grid system.