Study for theory and method of on-line detection of power system transient harmonic

This paper describes the theory of on-line detection of power system transient harmonic. A new on-line detection method using RMS (root-mean-square) of harmonics amount as trigger is presented for the first time. The passive sensor applying electric-magnetic isolated method and the synchronous sampling circuits used for tracking the changes of power system frequency are studied and designed. The contrasting analysis of the input wave with the reverse synthetic input wave by detecting results in a laboratory verifies the correctness of this method. Finally, the results of transient harmonic detected in the substation are given.