The Active Distribution Network Simulation Platform And Fault Characteristic Analysis

The rising of power demand, shortage of traditional energy resources and the integration of distributed generation, have created problems for the protection, operation and control of the traditional distribution network. The passive distribution network nowadays needs to be transformed into an active distribution network which has the ability of active control. To get the best performance of active distribution network, this paper has built a simulation platform of active, distribution network in the laboratory by scaling down the voltage levels. This paper also analyzed the failure characteristics of the distribution network with DGs, and researched into the protection of distribution network with high DG penetration.Firstly, the paper introduces the development of active distribution network, then summarizes the current research status of distributed power generation technology and active distribution network and its key technology at home and abroad recently, and expounds the significance of this study.Secondly, the analog element is used to replace the each link in the transformer substation and put up a substation or feeder section model. In such a model, the components of primary system are simulated with reduced physical objects, and constitute a miniaturized substation or feeder system. All kinds of fault simulation are carried out on such a system, so as to provide a reliable testing environment and conditions for the inspection and examination the protection.At the same time, various types of faults and automatic reclosing were applied in the active distribution network dynamic simulation platform. By comparing with the results of software simulation, the rationality of the simulation platform is verified.Then, this paper used DIgSILENT to establish the fault analysis model of distribution network with high DG penetration based on the topology structure of the active distribution network simulation platform. Aiming at the non-linear relationship between voltage of PCC and DG fault current with the control scheme of DG, a mutual iterative calculations method was used to resolve the problem. The the fault characteristic analysis of the active distribution network was completed, which provides the theoretical basis for the improvement of the protection scheme.Lastly, on the basis of adaptive current instantaneous trip protection, analysis of the effect of each point voltage to protection when failures occurred, and proposed an adaptive current instantaneous trip protection algorithm based on voltage acceleration. The topology of the simulation platform is used for validation of the protection’s selectivity.