Adaptive Protection Scheme for Overcurrent and Directional Overcurrent Relays In Distribution Networks with Distributed Generation

Smart grids (SGs) concept evolution around the world is highly encouraging the integration of distributed generators (DGs) with the distribution network to increase reliance on renewable energy sources instead of fossil fuels in electrical power generation. As result of varying DGs output, the predetermined current directions and short circuit (SC) currents values will change which introduce a formidable obstacle to the conventional protection system to maintain selectivity and sensitivity of the system among different operating modes. To tackle the above mentioned problems, this paper introduces directional overcurrent relays (DOCR) in the distribution system as well as adaptive protection scheme that combines online and offline method to update relay settings according to the prevailing network topology. The proposed scheme employs network monitoring unit and communicated relays to allow relay settings updates. MATLAB/Simulink software is used in modeling and simulation of the proposed scheme on the modified IEEE 4-bus. The proposed scheme can accurately detect direction of faults and adaptively reset relay parameters for different network configurations, fault types and locations.