Application of Kalman filtering for continuous real-time tracking of power system harmonics

The paper describes a unit based on an 8-bit microprocessor which enables continuous real-time tracking of the harmonics in the voltage or current waveforms of a power system. The unit is part of a distributed system for monitoring and controlling a power system which applies a 12-state Kalman filter to the voltage or current samples to obtain in real time the instantaneous values for a maximum of six harmonics as well as the existing harmonic distortion. The unit maintains a buffer in memory with the magnitudes of the harmonics detected in the last second and generates an alarm signal when the distortion level of an individual harmonic, or that of the group as a whole, exceeds the threshold established by the international standard.