Improved algorithm for on-line harmonic identification in HVDC application

The application of a newly developed algorithm is presented which allows the on-line measurement and tracking of the time-varying harmonic content of distorted voltage and current waveforms arising at the point of connection between HVAC and HVDC power systems. A novel discrete Kalman filtering technique is used which is able to rapidly acquire and accurately track the values of harmonic amplitudes and phases. The effectiveness of the presented method is demonstrated by a simple test case. Amplitude and phase acquisition is compared with that of an on-line FFT-based frequency scanner. The proposed algorithm has been applied in the identification and tracking of the harmonic content of waveforms obtained at the point of HVAC/HVDC common coupling. However, the technique is suitable for more general power system and power electronic applications where the rapid and accurate acquisition of harmonic properties is required.