Chapter 9 - DC microgrids protection: forthcoming approaches

Abstract

The designing of protection units for direct current (DC) microgrids is still a challenging task due to the quick and high-rising performance of fault current in DC systems, which have severe operation time restrictions for fault interruption schemes. A small variation in the fault current caused by high-impedance faults in DC systems might damage power electronic converters; thus, the accurate fault detection of these systems is vital. Because low-impedance cables and power electronic converters are used in DC microgrids, a precise location of the faulty part is required. The majority of existing models only take into account the power sources at one side of the line, where the fault current is produced. In the circumstance of meshed DC microgrids, fault current will be injected from both ends, and causing malfunction in the protection systems designed for radial systems. Additionally, the currently used communication-based techniques need either a quick communication network or information harmonization. This chapter introduces advanced localized fault location and detection strategies for meshed DC microgrids and clusters to overcome the aforementioned problems.