A Poverty Severity Index-Based Protection Strategy for Ring-Bus Low-Voltage DC Microgrids

The lack of an effective protection system may jeopardize resilience offered by low-voltage dc (LVDC) microgrids. This paper presents a protection strategy for ring-bus LVDC microgrids, which employs intelligent electronic devices and solid-state circuit breakers (SSCBs). This scheme is developed based on monitoring the modified squared poverty gap index difference that is calculated using the normalized fault-imposed component of current. A backup protection scheme for the case of the SSCB failure and a reclosing scheme for restoring the isolated zone in the case of temporary faults are considered in the protection scheme. The proposed strategy is capable of detecting and classifying the pole-to-pole and pole-to-ground faults within microgrid lines. Moreover, it consists of protection schemes for distributed energy resource and load laterals and is effective for high-impedance fault detection. The merits of the developed protection strategy are demonstrated through several time-domain simulation case studies.