Study On State Estimation Algorithm Of Distribution System And Software Development

Distribution Fast Simulation and Modeling(DFSM) is the core software of advanced distribution operations in smart grid, and state estimation is the most basic function in DFSM. Automatic adjustment of transformer tap plays a crucial role in keeping voltage level, such that it must be accounted in DFSM (especially in state estimation) . In this paper, the elements of Jacobian related to the ratio of different transformer connection groups are derived at first. And then a 3 phase power distribution state estimation software is developed based on the branch current state estimation method for distribution systems and the OpenDSS platform. At the same time, a new criterion of determine weights of measurement is presented in the state estimation algorithm. Finally, the IEEE-37 system and the IEEE-123 system are taken as illustrative examples, based on that the following conclusions can be drawn:1. The presentations of the elements related to the ratio of different transformer connection groups is derived correctively, such that the accuracy of state estimation in real power distribution system can be improved..2. The new criterion of weights of measurement can improve the stability and convergence speed of state estimation, where a large number of pseudo-measurements are to be used.