Background. The development of digital current and voltage transformers (DCVTs) is associated with the organization of a power supply system for the electronic components incorporated in the DCVTs. When implementing DCVTs of 35 kV and higher voltage classes, it is necessary to provide power to the electronic components on the primary side, i.e. on the high-potential side. The power supply for the electronic modules is designed according to a redundant scheme. There are various approaches to solving this problem, including organizing the power supply by converting electrical energy from the power facility's auxiliary circuits; for example, there are solutions to transmit energy using light through optical fiber. Another promising approach is to extract energy from the power line to which the digital transformer is connected by converting both the line voltage and current. The most promising approach is an integrated solution that simultaneously extracts energy from both voltage and current, thereby implementing a redundant power supply system. The difficulty of organizing power supply from primary current is that the current is constantly fluctuating and depends on the operation mode of the line, unlike voltage, which is virtually constant. Selecting the parameters of the current transformer and overload protection system for various modes, including emergency conditions with short-circuit currents is a complex but challenging task.
Materials and methods. The research methods chosen are a combined approach based on physical modeling of a power transformer operating with a rectifier and capacitor energy storage devices, and simulation using Matlab, Simulink, and Multisim software. This approach enables reliable verification of models designed in software packages with physical models.
Results. This article presents the development of a power source from the primary current passing through the DCVT. Mathematical models of current supply transformers with nonlinear loads have been developed. An approach to organize the power supply of electronic components over a wide range of primary currents has been formulated. A circuit implementation to limit energy supply during short-circuit currents has been proposed.
Conclusions. The proposed approach to modeling current transformers supplying electronic loads using mathematical models with parameter enumeration allows obtaining the required characteristics of supply current transformers in a wide range of initial parameters. The proposed methods to compensate high currents make it possible to eliminate overvoltage during short-circuit currents.