Métodos de polarização para proteção direcional de sobrecorrente em linhas de transmissão

Abstract

When thinking about electrical power systems, one of the most used protection methods is overcurrent protection. However, with the increase in distributed generation in the power grid, detecting only the location of the fault becomes insufficient, mainly due to the variation in the direction of the power flow. Therefore, a directional module is needed to inform the direction of the short-circuit current. It is in this sense that the present work seeks, through a study of polarization methods of the directional overcurrent relay, to implement an algorithm capable of defining whether the fault is located forward or in the reverse direction of the protection relay. Thus, an electrical system was simulated in the ATPDraw software, to simulate different configurations and locations of electrical faults. To this end, with an algorithm developed using Matlab software, the Discrete Fourier Transform was put into practice to extract the fundamental components of voltage and current phasors. In addition, such an application was used to: perform the calculations of the symmetrical components; and determine the directionality methods that define the direction of the faults worked here. Finally, this study demonstrates the effectiveness of the proposed algorithm, with a 100% success rate in the cases studied.