Abstract:With the rapid development of new energy power generation, the sub-synchronous oscillation are found frequently in large scale new energy collection areas, and the oscillation phenomenon in new energy collection areas is different from the sub-synchronous oscillation caused by series compensation and DC transmission system. which has the characteristics of hyper synchronous harmonics and frequency time-varying. In order to accurately extract and identify the sub synchronous oscillation signal in the new energy collection area, a method of detecting the main sub-synchronous and super-synchronous inter-harmonics based on power spectral density extreme point tracking is presented to identify the SSO Signal quickly and correctly. This method can quickly and accurately capture the weak frequency change and amplitude of inter-harmonics from the electric measurement response, and provide scientific reference data for the study of sub-synchronous oscillation prediction, protection and control. Through comparison of the traditional FFT analysis method and this method, the proposed method in this paper can better adapt to the time-varying frequency and have the advantages of higher detection accuracy at a specific frequency, and shows that the proposed method in this paper is correct and effective.