Dynamic synchrophasor estimation with modified hybrid method

摘要

Accuracy of synchrophasor measurements is one of the key issues directing the application of synchrophasor/PMU technologies in both transmission and distribution systems. This paper introduces a dynamic phasor estimation method for PMUs/IEDs based on modified time domain hybrid method. Dynamic phasor is estimated using Taylor expansion, where frequency deviation is derived directly from fitting parameters to avoid magnification of fitting errors. Using the samples from less than 1.2 cycles, the proposed method constructs three windows and then performs recursive DFT on both signal samples and modeled signal for parameter estimation. By scrutinizing the position for time-tagging and approximation, the precision of hybrid method is further improved and the implementation is made easier. This method is essentially rendered immune to harmonics by incorporating DFT in synchrophasor estimation. Performance of the method is investigated through simulations that prove high precision under both static and dynamic signals from real power system scenarios.