Equivalence of sections of electric power systems based on operating parameters in equivalence nodes

When modeling steady-state and transient operating modes in electric power systems, it is necessary to determine a section of the electrical network to simplify the processes occurring in the area not covered by equivalenting. In this case, it is necessary to identify equivalents and relationships with respect to the speci-fied section. The purpose of the research is to determine the parameters of the equivalent sections of power systems and their relationships with respect to the given nodes. Methods of mathematical modeling of the elements of power systems, methods of the theory of electric circuits, and methods of matrix analysis are used. To verify the results, electrical circuits of existing power systems and the software package “Auto-mated Workplace of Relay Protection and Automation Service” have been applied. The implementation of the algorithm is carried out using programming in the Python environment. An algorithm to determine the parameters of equivalent circuits of positive, negative and zero sequences is developed and tested when solving the problem of equivalenting a network section with respect to given nodes. Comparison of the levels of currents in case of short circuits according to the developed algorithm and the software package “Automated Workplace of Relay Protection and Automation Service” in the equivalent nodes shows the high accuracy of the equivalent results in accordance with the developed algorithm. The algorithm considers transformer connections when equivalenting with respect to the nodes located at different voltage classes, as well as phase shifts caused by the star-delta conversion.