PROJECT TITLE: Smart Protection of Microgrids
Collaborator: Rob Cuzner from University of Wisconsin-Milwaukee.
Funding: Scholarship from the Dept. of Energy Technology.
In future, distributed energy resources (DERs) will be utilized at consumption points. As a consequence, power flow and fault current would be bidirectional and topology-dependent; and hence the conventional protection strategies would be inefficient. Other challenges for AC microgrids (MGs) protection include compliance with the recent grid codes, considerable reduction in current fault during the MG transition from grid-connected mode to islanded mode, and coordination of protective devices (PDs) through high-speed communication links.
DC MGs are attractive for residential applications, electric vehicle charging stations, photovoltaic systems, telecom stations, commercial buildings and spacecraft. The recent growing interest in DC MGs is because of the advantages such as higher efficiency due to less power conversion losses, no needs to control voltage, frequency, reactive power and power quality; and no concern about synchronization. Although DC MGs offer the mentioned advantages, tendency for implementation of DC MGs encounters a tough obstacle, which is protection of dc MGs. In AC system, mechanical circuit breakers disconnect circuit when currents cross zero at every half-period; however, there are no zero crossings in dc MGs. Thus, currents have to be forced to be zero by additional means. Furthermore, low dc impedances make dc fault levels very high.
In this Ph.D. project, the main focus will be on new smart protection schemes for AC and DC MGs considering international standards (e.g. IEC 61850) and recently developed technologies. In this regard, novel reconfiguration strategies and well-designed control approaches will be proposed to realize a smart efficient protection system.
Publications in journals and conference papers may be found at VBN.