Performance Analysis of the Dual-Setting Directional Overcurrent Relays-Based Protection Considering the Impact of Curve Types and Fault Location

Abstract

Traditionally, directional overcurrent relays (DOCRs) have been used for protecting the meshed distribution systems with DGs. Recently, dual-setting DOCRs have been advocated as competent measures for such cases. Normal inverse (NI) type characteristics-based settings are usually utilized for the forward and backward direction operation of the dual-setting DOCRs. In this article, we aim to analyze the performance of reverse direction dual setting relays by using various curve settings and different fault locations. We propose the application of typical International Electro-technical Commission (IEC) curve settings namely NI, very inverse (VI), and extremely inverse (EI), and definite time settings for the reverse direction operation of dual-setting DOCRs while keeping the forward direction relay characteristics as NI type. The proposed scheme is tested using the modified IEEE-14 bus distribution system in the presence of synchronous-based distributed generations and using the IEEE-30-bus test system. The simulation results indicate that definite time settings for the mid-point and far-end faults provide considerably faster backup tripping times than the NI, VI, and EI characteristic curves. Whereas, in the case of near-end faults all characteristics provide the same tripping time.