Three static techniques (i.e., Power flow, Continuation Power Flow (CPF), and the Q-V curve) were used to assess the voltage stability of the power grid with a Solar Photovoltaic Generator (SPVG) and FACTS devices under nominal and heavy loading conditions. A static model is proposed for the power system that includes conventional power generation units and SPVGs with FACTS devices. Two models of SPVG were used (i.e., PV model and PQ model) to elucidate the effect of the SPVGs on the voltage stability under various operating conditions. The best location for FACTS devices was obtained under nominal and heavy load conditions using static techniques. The series and shunt FACTS devices under nominal and heavy loading conditions were compared using the abovementioned static techniques. The interaction between SPVGs and FACTS devices is detailed in this paper. The proposed approach was tested on the New England 39-bus standard test system, and the results confirmed the effectiveness of the proposed method under various operating conditions.