Power network system reliability and methods of calculation

Power supply reliability is one of the main criteria in estimation of power system networks. The decisions on radical changes in branch of electric power control and trade are still caused by essential monopolization, then reasoned with politicians, public, economic and technical factors and not less with international influence followed by ascendance to international alliances and wherewith connection of electric national network to the international grid. In order to prevent similar problems in a future it is necessary to elaborate new methods of power supply reliability assessment, which will use power network modernization and development. One of these methods is developed and examined in this paper. This reliability problems, which is devote modern, scientific and economic power system planning criteria and this calculation methods, review and assessment, is very actual.