Protection IssuesinMicrogridswithMultiple Distributed Generation Units

WWW: http://www.esat.kuleuven.be/electa Abstract --Theapplication oflocal generators in distribution gridshasconsequences fortheprotection system.In thispaper,protection issuesconcerning distributed generation arediscussed, followed by a discussion oftheresults ofsimulations. Thesesimulations concerntheeffect of localinduction generators on protection selectivity inasystem withparallel distribution feeders andtheeffect onfault detection. Itisfoundthatlocal induction generator canposea selectivity problem inasystem withparallel feeders whena line-to-line fault ora doubleline-to-ground fault occurs. Regarding thefault current detected atthebeginning ofa feeder, detected current islowest whenaline-to-line fault or a line-to-ground faultoccurs. Depending on therelay settings, this canresult inadetection problem. IndexTerms--Distributed generation, powersystem protection, selectivity, induction generator, powersystem simulation, short-circuit current.