In the present work, authors compare and estimate the efficiency of application of both methodologies of power systems’ nodal models reduction by means of load nodes elimination, which has been represented by arbitrary characteristics dependent from voltage and frequency. Inside the both methodologies, proposed by authors in they early works, there is an application of combination of quadratic approximation of nonlinear load and elimination of unknown by the Jordan method. Such comparison allows identifying benefits and shortcomings of each methodology, this by-turn simplifies the choice of optimal variant which is necessary for computation and analysis of the specific operation. Special attention is paid to the possible measure of inaccuracy in the both methodologies application. The estimation accuracy of behavior of reduced power systems was studied by means of different short circuits modeling in the various scheme parts. The case study is described on the part of the high voltage power system scheme with the help of power engineering software Eurostag.