Real-Time Measurement of Mean Frequency in Two-Machine System During Power Swings

This paper presents an algorithm for measuring mean frequency in two-machine system during power swings, which applies to sampled current signals in transmission lines with two sinusoidal components. The algorithm is based on rigorous mathematical deducing and recombines itself with Newton iterative technique and Taylor series expansion. The response of the algorithm is provided and the effects of key parameters, that affect the performance of the algorithm, are discussed. Computation requirements are modest and the technique has been implemented on a modern digital signal processor. The proposed technique has also been extensively tested using current signals obtained from dynamic frequency sources. Some test results are presented in the paper.