This paper presents the mathematical steady-state modelling of Static Synchronous Compensator (STATCOM) for voltage control of a bus and hence the variable of the controller. MATLAB programs have been developed for implementation of a few models of STATCOM. In this regard, Newton-Raphson load flow algorithm has been modified for incorporating models of STATCOM in some standard test bus systems. IEEE 5-bus system and IEEE 14-bus system are considered. Load sensitivity factors, which are defined as the effect of load on power system variables, are evaluated for load buses of the above mentioned test bus systems by increasing load on each load bus to 140% of base case value. Since load change affects node voltage, hence node voltage load dependency factor (NVLDF) of all buses are evaluated for finding optimal location of STATCOM. Thus this paper aims at evaluation of variable of STATCOM and finding optimal location for the same.