Influence of Rotor Damping Bars on Rotor Temperature Rise of Synchronous Condenser after Single-Phase Short-Circuit Fault

The main function of a synchronous condenser (SC) is to provide continuous and transient reactive power for the Ultra High Voltage Direct Current (UHVDC) converter station or the new energy power grid. However, the temperature rise of the rotor large teeth is the main factor which limits the transient operation ability of the synchronous condenser (SC). In this paper, a rotor structure of the SC with the rotor damping bars made of different materials in the rotor large teeth is proposed to reduce the temperature rise of the rotor large teeth. In order to obtain the influence of the damping bars on the temperature rise, the rotor loss and temperature distribution of a 300-MVar SC under the single-phase short-circuit fault are calculated by coupling the electromagnetic field, loss and temperature field models of the SC with the models of the power grid. For the damping bars made of the copper, aluminum and stainless steel, the rotor maximum temperature rises are calculated and compared. According to the maximum permissible temperature of the rotor core, the effect of the damping bars on the large teeth on the operating ability of the SC is obtained. This study can provide the theoretic basis for improving the operating ability of the SC under the single-phase short-circuit fault.