Technology for Determining the Operational Settings of Remote Protection of Electric Transmission Lines Using Mathematical Models

The correct functioning of relay protection (RP) devices largely determines the reliability and stability of the operation of electric power systems (EPS). The key aspect that in turn determines the behavior of protection in various emergency modes is their setting. Existing methods and means often do not guarantee the protection settings corresponding to real operating conditions, which is confirmed by the statistics of accidents in EPS. This problem is mainly the result of the inability to reliably reproduce transient processes in the power system utilizing computer systems used in practice for calculating the RP settings. The EPS simulator developed by the authors, i.e., the hybrid real-time power system simulator of EPS (HRTSim EPS), enables the adequate reproduction of the entire range of normal and emergency processes for a power system of any dimension, topology, and configuration through the use of detailed three-phase models of all elements of the EPS. Given this possibility, the task of modeling RP devices, including primary current and voltage measurement transformers, in detail is promising. The proposed protection modeling tools in combination with the capabilities of HRTSim EPS enable the development of new methods for determining the RP settings. At the same time, in each RP device, typical blocks that determine the algorithm for the correct functioning of the RP device, i.e., measuring elements, can be identified. This article presents an analysis of the main measuring elements of modern microprocessor-based RP devices and the principles for establishing the settings of these elements. This approach enables the adaptation of the settings to real operating conditions for the use of protection in power systems while minimizing the probability of incorrect operation. © Springer Science+Business Media, LLC, part of Springer Nature 2024.