PROTECTION COORDINATION FOR RELIABLE SUPPLYING MOTORS IN AUXILIARY POWER CIRCUITS OF THERMAL POWER PLANTS

Abstract

This article presents the research results on calculation of setting parameters and relay
protection coordination in the power supply diagram for electric motors at thermal power
plants. A typical power supply diagram for auxiliary electric motors is selected and the main
parameters of the elements including transformer, motor and conductors are collected.
Electrical Transient Analyzer Program (ETAP) supports the analysis of the starting characteristics
of the motor and the selection of different types of overcurrent characteristics of the relay
protection according to standards. Simulating typical scenarios shows that the coordination
scheme can effectively protect the motor and meet the relay protection requirements for electric
motors in the auxiliary power supply scheme of thermal power plants.