Desenvolvimento de uma interface gráfica para visualização do vetor impedância da proteção de distância em linha de transmissão

Abstract

This document presents an alternative for the visualization of the impedance vector in transmission lines in the time regime, applied to the distance function of transmission line protection. The protection equipment is responsible for activating the circuit breakers in case there is any disturbance in the transmission line. These devices monitor the voltage and current signals, using these values to determine the impedance vector in real time. This work proposes the development of a graphical interface, programmed in c# language, using the free tool from Microsoft Visual Studio Community as a development environment. In this interface, the Discrete Fourier Transform (DFT) of one cycle was used to calculate the fundamental phasors, from the voltage and current signals measured at the local terminal. With these fundamental phasors, the value of the apparent impedance or measured impedance for the phase or neutral distance elements is calculated. An interface was also developed to input the adjustment values for the MHO and Quadrilateral operation characteristics, typically used in protection relays. The results obtained from this computational interface allow a better understanding of the impedance vector trajectory and its final stabilization, within the operating area for each protection zone, defined by the adjustments of the 21/21N function. The good results demonstrate the importance of the Interface developed, both in the professional and academic scope, for a more detailed analysis of the distance function of a protection relay.