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

A dual-excited synchronous condenser (DESC) that has two sets of the field windings can absorb more reactive power through the d-axis negative excitation to suppress the transient overvoltage. However, the reactive power consumption ability of the DESC can be restricted by the temperature rise in the stator end region. In order to study the temperature distribution law in the stator end region under different reactive power consumptions, a 300-MVar DESC is selected as the investigation reference in this paper. The three-dimensional (3-D) electromagnetic-fluid-thermal coupling model in the stator end region of the DESC is established. The distributions of the flux density and temperature in the stator end region of the DESC are calculated, and the end structural component where the highest temperature appears is found. The variation laws of the highest temperature in the end structural components along with the increase of the reactive power consumption are revealed. The reactive power consumption limit of the DESC is obtained under the consideration of the maximum permission temperature for the end structural component. The paper can provide the theoretical basis for the optimization of the stator end structure and the reactive power consumption ability improvement of the DESC.