الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
Low voltage direct current (LVDC) power distribution systems (or so called LVDC microgrids) are of wide interest for various power applications. This is owing to their advantages over traditional AC power microgrids with regard to power density, power distribution efficiency and ability to increase penetration of distributed renewables such as wind turbines (WTs) and photovoltaic systems (PVSs), electric vehicles, and heat pumps. Further, short-circuit faults have enormous levels of current. There is a problem in utilizing conventional circuit breakers(CBs) to break DC faults. This problem is the nonexistence of natural points cross the zero reference of DC current. Moreover, utilizing the DC breakers is not an ideal solution this is because they are very pricy and bulky. So, protection systems adopted differential or over-current protection schemes.However, they must have robust communication network and need fully-distributed schemes. Along with that, there are additional challenges, for instance locating a fault in a microgrid, and surely the lack of standards, guidelines, and experience.
In this thesis, the problems of fault protection in DC microgrids are reported and a protection scheme is proposed. The goals of the proposed scheme are to detect the fault in the bus among devices and to separate the segment that contains a fault so the system retains operating without complete shutdown. To achieve these goals for robust protection system against short-circuit faults, a loop-type dc-bus-based microgrid system is considered.In addition, differential protection scheme is proposed that includessnubber circuits and solid-state bidirectional switches.
The suggested protection scheme for LVDC microgrid is designed using differential protection concept and is simulated usingMATLAB Simulink.The obtained results are presented and discussed.