Development of a Computer Application for the Calibration and Coordination of the 50/51 Overcurrent Relay

Abstract

In the present work, it was developed a computer application for the coordination and calibration of the 50/51 over-current relays for radial systems. Through this application the graphs of the relays curves were observed modifying the input variables such as Tap Current (51) and Instantaneous Current (50), TCs, Types of Curves and their Dial for each one of them, in order to calibrate and coordinate the protections between curves by means of the time of action between the Relays in the program Coordination of Protection of electrical overcurrent (CPSElectric) developed by means of the programming tool Matlab r2019a, one of the applications incorporated in this platform, the App Designer, is being used this is one of the new programming options in Matlab r2019a that allows us to reduce the time of interface development and the ease of application design, for which we can make the program more interactive at the time of its use since it is focused to be part of the electrical protection laboratory of the Technical University of Cotopaxi improving the students' learning when discussing the 50/51 over current protection, allowing to obtain the visualization of results such as the operation times of the instantaneous currents (50) and their operation margin time between curves in a graphic way to guarantee the results was based on different standardized norms such as IEEE Std C37. 112-2018 "Standard for inverse time characteristic equations for overcurrent relays" and IEC 60255-3 "Measurement and protection equipment relays.