Fault Recognition and Isolation Approach in Direct Current Microgrids

Abstract

The widespread power electronics dominated microgrids and their practical implementation in intelligent environments demand reliable and dedicated protection philosophy. In addition, the fault recognition and isolation of faulty line in ring configuration direct current (DC) microgrids is a significant challenge. Exploration of parameter-based protection techniques is attractive because of limitations associated with the traditional overcurrent protection and differential approaches during high resistance faults. In this paper, the proposed protection method has adopted the computed line parameters to identify the faulty line accurately. The resistance is computed by comparing pre-fault voltage with fault voltage immediately after the fault inception. Subsequently, the sign of computed resistance at both ends of the line is employed for proper discrimination of internal and external faults. To investigate the genuineness of the proposed approach, numerous fault cases like low and high magnitude resistance faults, fault at different line locations and the impact of fault in other healthy lines were considered and simulated using the MATLAB/Simulink platform on 350V, 500kW DC microgrid. It is ensured that proposed technique recognizes the fault rapidly even during high resistance faults and protects the diodes of power electronic converter. Moreover, this scheme strengthens the dependability and security of protection devices.