Estimation of power system parameters based on load variance observations - laboratory studies

The paper concerns important problem: estimation of power system equivalent parameters. Knowledge of these parameters is needed to determine disturbances propagation ability through power grid. Authors present new techniques, which may significantly improve accuracy of noninvasive power system identification. These are: voltage and current coherent resampling algorithm, which ensures that sampling frequency match actual fundamental frequency of power system, so the DFT analysis is almost leakage-free; envelope detection algorithm which allows to estimate equivalent impedance of the load and its variability for fundamental frequency; the method of load change detection ensuring that only fragments having sufficient amount of information for power system identification will be used in parameters estimation. The proposed methods were tested using laboratory power system model of known parameters. Presented results of laboratory experiments confirmed correctness of the described methods.