New Current Protection Scheme Considering Distributed Generation Impact

In the distribution network with distributed generation(DG),the single-source radiate network based protection scheme is no longer suitable and loses its original protection coordination.Based on multi-DG distribution network structure and fault current characteristics,this paper proposes a new adaptive fault location method which can be used for current protection design.This new current protection scheme includes two steps:first,the fault search direction is obtained through current magnitude comparison;this will narrow down the possible fault region within two three-branch buses.Secondly,phasor relationship between current positive sequence component and load current at the both ends of the feeder is used to locate the fault section along the feeder.This is realized in an adaptive fault searching region lock matrix algorithm,which avoids the matrix multiply operation.This is simple and practical.The validity of the proposed protection algorithms is verified by the simulation result.