The Effect of Fault Variables in the Performance of Quadrilateral and MHO Relays
João Tiago Loureiro Sousa Campos1; Washington Luiz Araújo Neves1; Flávio Bezerra Costa2
1 Universidade Federal de Campina Grande; 2 Universidade Federal do Rio Grande Do Norte
doi:10.20906/CPS/SBSE2016-0376
Resumo
In this paper, the influence of fault variables in the quadrilateral and mho relays are evaluated. The mho and quadrilateral relays are developed to be more accurate as possible according to manufacture datasheets. Therefore, the quadrilateral and mho relays are composed by an over-current, directional, and reactance relays, in which fault type relay to distinguish ground faults from phase-phase faults is used. The influence of the fault variables such as fault type, distance, inception angle, and resistance are investigated in order to evaluate the implemented relays. Also, an explanation about relay fundamentals is exposed. The quadrilateral and mho relays were tested in a standard transmission power system protection in single and double line configurations. Several fault simulations were performed varying the location, as transmission line and buses. The results showed that the quadrilateral relay is reliable for ground faults whereas for three phase faults it has many misoperations. In addition, the usage of the mho relay in phase-to-ground faults depends of resistance coverage needed for high resistance faults and mho relay needs to be improved.
Palavras-chave: Quadrilateral; Mho; Relay; Protection; Distance