Introduction. The magnetic systems of high power microwave generators, such as relativistic reverse wave lamps and klystrons, are powered with a direct current of up to 1 000 A from supercapacitor storage for several seconds. When designing power supplies for these magnetic systems, there is always necessary to determine the energy characteristics of the storage device. The analytical calculation of the characteristics is difficult, because of dynamic changes in some parameters of the magnetic system and storage device during current flow.Aim of the Study. The aim of the article is to create and experimentally test a mathematical model describing the process of powering a multi-section magnetic system with direct current from a supercapacitor storage device.Materials and Methods. The simulation takes into account the dynamic changes in the magnetic system parameters when current flows. The supercapacitor storage device is represented as a simple RC-circuit, the parameters of which are the nameplate data of its capacitance and internal resistance. The description of a storage device discharge process is based on the energy balance data. This model is implemented in the National Instruments LabView 2012 software package and has a user-friendly graphical interface. The simulation results were tested on equipment consisting of a power supply based on a supercapacitor storage device and two-section magnetic system.Results. The simulation results showed a good agreement with the experimental ones. According to the experiment results, the waveform of the current and voltage of the storage device, and the maximum duration of current stabilization were close to the simulation results. At the same time, the nameplate data of the capacity and internal resistance of the storage device characterize well its real parameters, taking into account the peculiarities of working together with the current regulator and the pulsed nature of energy consumption.Discussion and Conclusion. The slight difference in the results is explained by the deviation of the actual parameters of the storage device from its passport data and by the difference in the temperature of the windings used in the experiment and simulation. The calculation of the energy characteristics of the storage device is performed on the basis of the energy balance, which allows scaling the load through adding any number of energy consumers with independent current stabilization in each.