Analysis of island-operated distribution networks with distributed induction generation under fault conditions

This paper presents an analysis of an island-operated distribution network with distributed induction generation under different fault conditions. In the first part, the behavior of an island-operated induction generator connected to a distribution network is presented for short-circuits at different locations in the network, with varying values of fault resistance, initial loading conditions and generator rating. The second part of the paper studies the behavior of the induction generator during earth-faults on the distribution network. Unearthed, directly and resonant earthed networks are considered. The effects of the total capacitance to earth, largely due to the presence of cables, are analyzed in the case of an unearthed network. Then, the influence of a STATCOM on the fault behavior of the generator is briefly discussed and in the last part some considerations on network protection are done, under the assumption that selectivity is not required when operating the network as an island.