<p>The digitalization of electrical networks is declared in the concepts and regulatory documents applied by the head companies of the Russian electrical network complex. The development of the relay protection and automation system (RPA) is underway, more advanced devices are created, including for future digital distribution networks of 6 – 35 kV, microgrids with distributed generating facilities, migrating load, complex topology and modes. This is required due to the imperfection of the existing traditional current relay protection (RP) system for 6 – 35 kV networks with electromechanical and static RP devices or digital devices simulating their algorithms, which includes insufficient sensitivity, operating speed, non-selectivity of complex-configuration networks, lack of ability to obtain complete information about network damage, as well as labor intensity of adjustment, testing, and changing relay operating values. Nevertheless, electromechanical RPAdevices will remain in digital distribution networks or their individual sections where it is necessary to ensure low-cost electricity supply. In this case, the operating speed of traditional protection devices at a small number of stages is ensured by means of dependent current-time characteristics of overcurrent protection. It is known that for the new generation of digital relays coordinated with them, it is possible to abandon the set of various current- time characteristics and replace them with the piecewise linear approximation of a large number of independent stages (conditional settings). This will simplify calculations due to automation and speed up protection. The calculation of a large number of steps in digital current protection devices can be performed automatically using the method developed by the authors.</p>