Adaptive IEC 61850-based overcurrent protection in active distribution systems

Overcurrent relays (OCRs) with fixed setting parameters are the primary protection devices for distribution network feeders. The integration of inverter-based distributed generation (IBDG), such as photovoltaic (PV) systems, into active distribution networks (ADNs) introduces significant challenges, including blinding zones where a fault cannot be detected by the traditional OCR with fixed settings. In this paper, an adaptive protection scheme is proposed to address protection blinding by dynamically adjusting the IEC overcurrent curves, available in all relays, based on the IBDG level of generation. The operational status of the IBDG can be determined by the time of day (e.g., PV on or PV off) or through data received via the Advanced Metering Infrastructure (AMI) infrastructure. Accordingly, the adjustment can be either scenario-based or continuous. A case study and the use of real-time simulation and actual protection relay (employed as hardware-in-the-loop) utilizing the IEC 61850 standard demonstrates the method's effectiveness and practicality.