Research to Improve the Fault Indicator Malfunction using Current Direction in Distribution Automation System

SUMMARY In this paper, an improved method for generation of fault indicator in FRTUs is proposed for the Distribution Automation System. It is found that the upper side fault current direction is different from the down side fault current direction. Therefore, in order to prevent the generation of wrong fault indication information for FRTU at the down side of the fault, an improved fault indication generation method is developed. It not only the basic conditions, but also the directions from the angle difference between zero and positive sequence currents is considered to generate the fault indication information. In case study, the proposed method has shown the reliability in generating the correct fault indication information for many kinds of faults according to conditions.