ALGORITHM FOR LINEAR STATE ESTIMATION BASED ON CURRENT SUMMATION METHOD APPLIED TO THREE-PHASE POWER DISTRIBUTION NETWORKS
Distribution Systems. State Estimation. Current Summation Algorithm.
Electric power distribution systems have undergone several advances in the last decades, necessary to guarantee the reliability of these networks due to the increase in the number of consumers and, consequently, their physical extension. This work presents the development of a branch-current-based algorithm for the implementation of a linear formulation of the state estimation problem in three-phase distribution networks. In the developed method, the modules of the branches and nodes currents are estimated based on the method of Weighted Least Squares and a load adjustment algorithm. The meters located in the analyzed feeders provide the values of the measured quantities and an approximation of the average power factor of the loads located downstream of these measuring points, while pseudo measurements are used to make the system observable. On this method, an iterative re-estimating process was implemented, where the parameters estimated in the first estimation are used to update the loads, the branch currents and the new variances. For the validation of the method, the states of two real feeders were simulated. The obtained results show that the developed method can provide the state of the system with adequate precision for distribution systems with a reduced amount of measurement points along the feeder, besides presenting a low computational processing time and simplified modelling. There was also a proximity between the proposed estimator and the re-estimation method, proving that the load adjustment process already provides pseudo-values close to the estimated values.