Efficient frequency-adaptive amplitude tracking algorithms for protection purposes

The new, fast and adaptive algorithms for measurement of signal amplitude for protection and control purposes are presented. The algorithms are intended for amplitude tracking of the distorted sinusoidal signals with varying frequency. Contradictory requirements of selective measurement of the fundamental frequency component parameters and algorithm application in off-nominal frequency conditions become reconciled due to introduction of the adaptivity idea. Wide frequency band features of the estimators are obtained by adaptive on-line changes of the orthogonal filter parameters (data window length) and coefficients in the measurement equations according to the observed actual frequency being tracked with special but simple digital procedure. The developed algorithms have been tested with MATLAB and EMTP-ATP generated signals. Practical implementation of the adaptive scheme on the TMS signal processor is also described.