Broadband oscillation signal extraction method and device

The invention relates to the technical field of broadband oscillation, and discloses a broadband oscillation signal extraction method and device. An electric signal in an original three-phase static coordinate system is converted into an electric signal in a dq0 coordinate system, and due to the fact that sub-super-synchronous current in the system can be changed into fluctuation components in the dq0 coordinate system, the frequency of the sub-super-synchronous current is reduced; therefore, power frequency active and reactive components under a dq0 coordinate system can be extracted only through a low-pass filter, and then a three-phase current signal without sub/super-synchronous signals can be obtained through dq inverse transformation. And finally, subtracting the current from the three-phase current in the original line to obtain a sub/super synchronous signal in the line. The signal required to be extracted is obtained by subtracting the power frequency current signal in the system from the original cu