A Study on the Development and Validation of a Fault Detection Algorithm Based on the RLC Equivalent Model for a Full-Bridge MMC Bipolar MVDC Distribution System

This paper proposes a non pilot fault detection algorithm for a bipolar Medium Voltage Direct Current(MVDC) distribution system based on a Full-Bridge Modular Multilevel Converter(FB-MMC). The algorithm uses local measurements of voltage, current, and rate of change of current(ROCOC), and detects faults when measured values exceed threshold for a predefined time delay. The ROCOC threshold is derived from the fault current and its derivative, modeled using the RLC equivalent circuit of the MMC. The proposed algorithm is evaluated under various fault and load variation scenarios in MATLAB/Simulink, and demonstrates reliable detection performance and stability under non fault conditions.