Research on mechanism of power system low frequency oscillation based on damping coefficient

In this paper, the mechanism of low frequency oscillation of power system is studied from the perspective of the damping coefficient of the generator. Based on the analytical expression of damping coefficient, the factors which affect the damping coefficient are divided into four parts, damping of motor, electric generator and connecting line reactance, electric generator head load, and the transmission power of connecting line. The specific conclusions about the influences of various factors on the damping coefficient are drawn through further analysis. Finally, the time domain expression of state quantity of power-angle deviation is worked out according to the movement equation of the generator rotor, and certain conclusions about the damping coefficient's influence on low frequency oscillation of the system is obtained.