2MATOUKA M F. A wide-range digital power/energy meter for systems with nonsinusoidal waveforms[J ]. IEEE Trans,, 1982,29( 1 ): 18-31.
3BEGOVIC M M,DJURIC P M, DUNLAP S,el al. Frequency tracking in powemetworks in the presence of harmonics [J ]. IEEE Transactions on Power Delivery,1993,8 (2): 480-486.