An optimal and adaptive coordination strategy for conventional and advanced overcurrent protections

Abstract

Distributed generation challenges the conventional overcurrent protection, demanding cost-effective strategies that utilize the existing infrastructure. Solutions based on traditional protection schemes avoid additional investment, making them viable for smaller utilities. Advanced tools like optimal coordination and adaptive readjustment can enhance conventional protections. Existing optimization approaches ensure sensitivity through constraints but often allow low-sensitivity settings, limiting performance. This trade-off arises because operating in the most sensitive range can compromise reliability, making balance a key challenge. This paper proposes an optimal and adaptive coordination strategy to address a critical gap in protection sensitivity. The optimization problem constrains solutions to the most sensitive settings while considering common protection devices in distribution systems: fuses, reclosers, and relays. Additionally, a dynamic readjustment strategy maintains reliability through two methods: seasonal adjustments based on adjustment groups and monthly readjustments, ensuring feasibility in both conventional and advanced grids with online protection updates. Compared with state-of-the-art criteria, the proposed strategy improves operating times up to 6.42% through monthly adjustments and 4.04 % through group-based adjustments while preserving coordination and reliability. These results demonstrate that this method effectively enhances protection sensitivity without compromising key quality indicators.