Influence of Temperature Rise in Stator End Region on Reactive Power Consumption Ability of Dual-Excited Synchronous Condenser

The direction of the excitation magnetomotive force (mmf) for a traditional synchronous condenser (TSC) cannot be adjusted, so that the ability of the reactive power consumption is restricted. While there are two sets of field windings on the rotor of dual-excited synchronous condenser (DESC) and the direction of the excitation mmf can be regulated, therefore the consumption ability of the reactive power can be improved by the reverse excitation. The temperature rise in the stator end region is a key factor to restrict the reactive power consumption ability of the DESC. In order to study the loss and temperature rise of the different end structural components under different reactive power consumptions, a 300-MVar DESC is selected as the investigation reference in this paper. Mathematical model of the three dimensional (3-D) transient electromagnetic field and loss in the end region are established. The distributions of the loss and temperature in the end structural components of the DESC are calculated and compared with that of the TSC. The end structural component that the highest temperature appears is found. The variation law of the maximum temperature in the end region along with increase of the reactive power consumption is revealed. The flux densities and the losses of the end structural components are affected by the conductivity of the metal shield. The paper provides the theoretical basis for improvement of the optimal design of the stator end region of the DESC.