An Improved Overcurrent-Distance Coordination Strategy to Minimize Cascaded Tripping Problem in Protection of Distribution Systems: A Case Study for The Libyan Distribution System

Abstract

The mis-coordination problems between OverCurrent Relays (OCRs) and zones of Distance Relay (DR) in transmission lines are one of the causes of blackouts globally. Mixed coordination strategies between overcurrent and distance protection schemes in distribution systems can overcome such problems and, as a result, it is possible to create more efficient power systems. This study offers practical practice for the coordination of Distance and overcurrent protection scheme by enhancing the setting of overcurrent protection scheme in order to prevent cascade tripping of upward distance relays when three-phase faults happen. The unique procedure is also improved for adaptive protection schemes. In order to assist illustrate the feasibility of the scheme proposed, tests on simulation packages (NEPLAN and ETAP) for a part of the electrical network in Benghazi that includes both lines between the garden stations, Salmani and Bougrain are conducted using practical data during different fault scenarios. The outcomes of the simulation validate the effectiveness of the proposed scheme and confirm that the approach proposed works correctly in different scenarios.