State Estimation Of Distribution Network Considering Distributed Generation

Recently,with the global energy shortage,environment pollution and climate change getting worse,speeding up the development and utilization of renewable energy has become the consensus of the international community,so more and more distribution generations are connected to schools,hospitals,large office buildings and some factories of standby power generation unit.Under the new situation,the structure and operation mode of power system are becoming more and more complex,and the automation level of power system dispatching center needs to be developed from low level to advanced level.Modern dispatching system requires the establishment of a reliable and complete real-time database,which can quickly,accurately and comprehensively grasp the actual operating state of the power system,so as to ensure the safety and economy of power system operation.Based on the characteristics,the problem of state estimation of distribution network with distributed generation is studied in this paper.First,state estimation algorithm of distribution system based on branch current is improved,and the three-phase imbalance and DG factor of the distribution network are considered.In order to analyze the effect of DG on three-phase state estimation of distribution networks,the characteristics of major distributed power are studied,and according to its characteristic mainly equivalent for PQ,PV,PI,P-Q(V)four node model,and gives the measurement processing method in the algorithm and corresponding jacobian matrix elements in processing method.Next,when there are multiple bad data interaction,only by using st andard residual error prone to residual contamination and the phenomenon of residual submerged,so we introduce fuzzy clustering analysis method.We use dynamic classification,and determine the best classification,which is divided into good data and bad data.We modify the node power balance equation to provide a highly reliable data source for system state estimation.Finally,We use IEEE33 node example to verify the correctness of the three-phase distribution network state estimation algorithm based on the branch current.The access to DG in the distribution network can increase the measurement redundancy of the system,so as to improve the accuracy of the state estimation of the three-phase distribution network.The standard residual method was used to identify the low probability of all bad data.Therefore,the method of combining standard residual method and fuzzy clustering method can effectively avoid residual pollution and residual inundation phenomenon,and enhance the effect of detection and identification.The results show that the algorithm has good practical value.