A new method is proposed to identify strongly correlated generators in low frequency oscillation using the concept of energy supply on the port (ESP). The quantitative relationship between the quadratic form energy function and participating factors that indicate the active degree of generators in one oscillation mode is revealed. Inspired by the fact that the ESP concept evolved from the traditional energy function

this paper theoretically proves

under the condition of using the classical power system model

that the distribution of the instantaneous amplitudes of the periodical component of power supply on the port (PSP) is consistent with the distribution of participating factors. A heuristic method is finally presented to identify strongly correlated generators using the instantaneous amplitudes of the periodical component of PSP. Test results obtained from cases of general power system models have validated the effectiveness of the proposed method. This work is supported by the Foundation for Innovative Research Groups of the National Natural Science Foundation of China (No. 51321005)and National Natural Science Foundation of China (No. 51177079).