State Estimation of the Micro-grid

For the goal of actual needs of power companies, this chapter develops a state estimation procedure of the micro-grid, using branch currents as state variables, so that the measurement functions of nodes and branches can be expressed by these state variables. Micro-powers can be processed as different node types in grid or isolated operation according to different control methods that can also provide various real-time measurements in the state estimation. In this chapter, an IEEE-33 nodes micro-grid is adopted as an example. The performance of the state estimation program is tested by contrasting the estimated values and true values given by the power flow calculation. The result proves that the estimated values are close to true values and the method is feasible.