An improved three-phase power flow calculation method based on virtual neutral point

In order to improve the accuracy of the calculation model so as to improve distribution automation level, this paper presented a new three-phase power flow calculation method for three-phase distribution network. Based on the special network structure of distributed system and the relation between current in the three phases, virtual neutral point was brought in the model. By the virtual neutral point, it is easy to get the relation between the load in each node and the injection current it caused in the according node. And then the three-phase power flow calculation model could be built by back/forward sweep method. In order to obtain the solution of the presented model, a new kind of mixed iterative algorithm was proposed. The mixed iterative algorithm combined the back/forward sweep method with improved Newton Raphson method. In the last, the presented method was tested by a practical distribution network with six buses and IEEE 33-bus system and the power flow results was given to show the accuracy and validity of the proposed model and algorithm.