Damping Torque Coefficient Affected by Different Rotor Damping Structures of Turbo-generator during large disturbance

Damping structures of synchronous generator such as rotor damping bars, iron core and slot wedge can provide positive damping for the dynamic process of power system, while magnetic saturation, distortion and skin effect during the large disturbance process make the three-part damping appear nonlinear. In order to quantitatively describe the strength of three component damping effect during the large disturbance process, the time-step finite element method and the polynomial approximation method are coupled to study the Damping Torque Coefficient (DTC) during the large disturbance caused by the short-circuit fault. The influence of three component damping structure on DTC is studied. The damping strength of each component is obtained by comparing the individual and combined effect of three component damping structure. The results provide theoretical basis to the enhancement of power system stability by improving rotor damping structures of synchronous generators.