Oscillation Characteristics and Extraction Method of AC Signal During the Small Disturbance Dynamic Process of Power Systems

Abstract

Nowadays, the oscillation form of alternating electrical quantities such as voltage and current in power system oscillation is becoming more and more complex. In order to correctly obtain the characteristics of signal oscillation for system oscillation analysis, it's necessary to understand the formation and evolution mechanism of AC signals. In the dynamic process of oscillation after the system is disturbed, the unbalanced power drive equipment changes the amplitude/frequency of the internal-voltage in the port to generate alternating voltage/current in the network. Each alternating electrical variables of the system evolves in the form of its amplitude/frequency modulated. Based on this, this paper first defines the oscillation characteristics of the AC signal at the initial stage of the small disturbance dynamic process of power system based on the above AC signal formation and evolution mechanism; Then the corresponding signal characteristics extraction idea and a corresponding demodulator structure are proposed; Finally, simulation verifies the effectiveness of the demodulator.