Abstract: The problem of security and stability of new power systems is becoming increasingly prominent when regional faults occur. As an effective means to prevent the spread of faults,active splitting has gradually gained attention in the study of system stability. The active splitting is studied from two aspects of coherent unit clustering technology and splitting section search technology. Combined with time-frequency analysis,feature extraction,graph theory and other methods,the coherent unit clustering technology based on improved clustering algorithm ＆ splitting section search technology based on multi-layer graph segmentation are proposed,and the applicability is verified in IEEE-39 node standard test system.