An investigation of distance protection function applied for shunt reactors

This article investigates the use of the distance function to protect shunt reactors. For this purpose, mho phase comparator is assessed. To carry out a comparative evaluation, the distance function performance was further compared with the differential function performance. Moreover, the Alternative Transit Program (ATP) was applied to model an electrical system, in which the reactor is subjected to different faults, including phase-to-phase, phase-to-ground, turn-to-ground and turn-to-turn faults. The performance of the evaluated distance function was also investigated against the number of turns involved and the leakage factor. From the results obtained, it is suggested the joint use of the distance function with the differential protection, because if the differential function does not operate, distance function would guarantee the operation for internal faults, including turn-to-ground and turn-to-turn faults, increasing reliability of protection scheme for shunt reactors. Also, the present study may serve as a guide for further studies, for example, that evaluate the use of distance function to protect iron-core reactors.