Splitting and paralleling research of the distribution system which contain distributed generation (DG) under the power system faults

With the using of the renewable sources increasingly, application of the distributed generation (DG) in the distribution system acquired more attention. After the power system faults, distribution system which contains many DGs would usually cut off the DGs from the distribution system at the joint where the DGs connected into the system term less. However, considering the enlarge scale and the capability of the DGs, also with the improving ratio of the DG to all generator, cut off the DGs from the distribution system directly without analysis of the splitting point detailed after the faults occurs in the power system, which can not improve the reliability of the distribution system and made the effect of the DG at a discount. This paper would firstly study the bevior of the DGs after the fault occurs in the power system, classify the DGs according to the parallel operation interface on power system and the control strategy, so some DGs which can not keep operation steady would be eliminated from the distribution system to simply the analysis. The installation position of the splitting point can be fixed based on the fault place and the load location in the power system, then the new splitting criterion and the logic flow are given, so the DGs and its local load can organize island to keep on operation. After the fault cut off, the system resume natural operation, based on demand of the stable operation of the DGs in various island, controlling the different DGs together in order to satisfy the condition of the paralleling in the splitting point remote to the DGs in the island, the parallel operation criterion and the logic flow are also given. The above-mentioned contents are all lie on the distribution automation system (DAS), however, the traditional DAS which research contents and functions can not satisfy the demand of the distribution system which contain DGs. So the research contents and the functions of the DAS which would be applied in the future were also mentioned in the paper.