A Centralized Post-Transient Derivatives Based Protection Scheme for LVDC Distribution Networks

With the growing integration of renewable energy sources, Low Voltage (LV) distribution networks are experiencing increased demands to accommodate a diverse range of renewables. As a potential solution to alleviate the strain on existing distribution networks, the adoption of Low Voltage Direct Current (LVDC) distribution networks is under consideration. However, establishing reliable and selective protection techniques remains a significant challenge. Several protection algorithms focus on significant fault currents, fixed threshold settings, and high sampling frequencies for effective coordination, which often face limitations in low fault current scenarios or require costly data acquisition techniques. Therefore, this paper presents a novel centralized Post-Transient Derivatives (PTD) based protection scheme, which Leverages only the sign of Post-Transient Voltage Derivative (PTVD) and Post-Transient Current Derivative (PTCD). This approach addresses the selectivity constraints of existing voltage and current based solutions, particularly when lower sampling frequencies are applied. The proposed scheme is validated against various fault scenarios on an LVDC test network simulated in PSCAD/EMTDC and verified using an RT-Box based hardware test bed.