Characteristics of distributed generation system and related research issues caused by connecting it to power system

The characteristics of distributed generation (DG) system are presented in brief. In three aspects, i. e., the construction period and operation period of power grid containing DG and under the situation that accidents occur in the power grid containing DG, some problems caused by connecting DG to power grid and related research issues are discussed. The problems and issues are as following: when the proportion of DG in the planning scheme increases, the complexity of power grid evidently raises, and connecting DG to power grid brings the influences in the structure of distribution system, load forecasting, site selection of substations and so on; during the operation of the power grid, DG influences on intrinsic frequency, power flow, voltage oscillation and high-order harmonics of the power grid; the features of power grid containing DG find expression in island effect, system reliability and short-circuit capacity while accidents occur. Present research situation of above-mentioned issues and the direction in the research are expounded.