The current stage of the world energy development is characterized by the creation of powerful territorial and integrated power systems. A gradual unification of the energy markets of different countries is currently going on within a free market: the configuration of networks has been changing, additional relations appear, new energy companies and unions are formed, a sector of renewable sources is rapidly developing with its characteristic distributed generation (decentralization), therefore, the most urgent matter of finding and creating new methods and algorithms for calculation and analysis of complex EPS. In particular, it concerns the issue of problem solving of large-scale power systems with a detailed accounting of basic elements of the system. All ongoing and planned changes both directly and indirectly affect the network configuration, which in its turn leads to the appearance of additional generation and load nodes and, consequently, it requires careful economic and technical computations, in particular, the static stability assessment of the power system.