Development of a method for real-time assess-ment of post-contingency nodal voltages is introduced. Linear network theory is applied in an algorithm that utilizes Thevenin equivalent representation of power systems as seen from every voltage-controlled node in a network. The method is evaluated by comparing with results from time domain simulations and power flow calculations using Newton-Raphson’s method. It is concluded that the developed method performs better than Newton-Raphson’s method in reproduc-ing results from time domain simulations. Discussion includes considerations for further development for facilitating treat-ment of composite loads.