Abstract: The development of modern expensive electrophysical installations compels to conduct preliminary researches which at this stage are expedient for carrying out on the basis of numerical simulation of the processes proceeding in the main power knots of installation. Application of numerical modeling became especially attractive in connection with emergence of a number of standard programs. Such research significantly accelerates and reduces the price of the process of development, allowing to reveal and eliminate in passing the most strained and emergency operation of work of installation. The problem becomes complicated also by the circumstance that though the development of knots of installation on the basis of commercial products makes it cheaper and accelerates it but at the same time generates a problem of compatibility of parameters of knots. The research presents the modeling of the modes of installation with a problem of coordination of its separate blocks to be executed. The source load is electrophysical installation with consumption current to 7 MA. The research demonstrates numerical modeling of processes being carried out in the most problem parts of the scheme. The model of the converter developing the alternating echeloned voltage has been worked out.