A communication-free active unit protection scheme for inverter dominated islanded microgrids

Large-scale integration of different renewable energy resources introduces significant challenges to the protection microgrids (particularly those that may operate in islanded mode), including variable and low fault levels, difficulty operation main backup with their coordination, bidirectional power flow during faults. As a solution such challenges, this paper presents novel active strategy for inverter dominated coordinates actions control strategy. The proposed scheme dictates specific from interfaced distributed generator (IIDG) controller inject harmonic components into microgrid fault. Relays throughout network detect analyse injected identify faulted section, take appropriate isolating actions, without any requirement relay-to-relay communication. achieves selectivity coordination using definite time delay settings. To verify performance scheme, realistic model incorporating has been developed MATLAB Simulink, where wide range scenarios have simulated variations location, type, resistance, line impedance, combinations IIDGs (including connection synchronous generator). Additionally, case studies real-time digital simulator (RTDS) platform also conducted validate real-time, multiple relays implemented as hardware prototypes running on OPAL-RT — thereby demonstrating system hardware-in-the-loop (HiL) configuration. It is shown highly effective detecting faults, proper discrimination, stability provision backup, under all investigated scenarios. • Islanded challenges: low/variable/bidirectional current reported unit provides an communication-free simple cost-effective - operates injections rapidly isolates faults