Efficient protection scheme for low-voltage DC micro-grid

Detection of shorted DC faults and high-resistance faults on ring type low-voltage DC (LVDC) micro-grids imposes an elusive challenge. This research work proposes an efficient and reliable protection scheme for DC system in order to boost up LVDC system adoption on large scale, despite lack of proper standards and mature experience in DC system protection. In order to ameliorate these deficiencies, a wavelet transform-based fast fault protection scheme using local measurements has been proposed for eliminating threat to voltage source converters during fault. The features extracted using wavelet coefficients are utilised as key indicators to identify the fault with wide variations in operating conditions. The LVDC micro-grid system has been simulated using real-time digital simulator and the test results studied show a great potential ability in performing DC fault detection and classification task efficiently. Furthermore, the robustness of the proposed protection scheme is capable of fault line identification and setting up desired relay selectivity in the LVDC distribution system.