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

A synchronous condenser (SC) can provide the transient reactive power support for the Ultra High Voltage Direct Current (UHVDC) converter station. However, the rotor temperature rise is generally the main factor which limits the transient operation ability of the SC. In this article, 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 rotor temperature rise. In order to obtain the influence of the rotor 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 model 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 transient operating ability of the SC with the rotor damping bars made of different materials is obtained under the single-phase short-circuit fault. This study can provide the theoretic basis for the improvement of the transient reactive power support capacity of the SC under the single-phase short-circuit fault.