A combined‐constraints‐based optimization methodology aimed at temperature balancing for radial layered encapsulation structure of bridge arm reactor

Bridge arm reactor is widely used in voltage sourced converter based HVDC transmission projects, whose temperature distribution is the critical factor determining its operating life. However, the prevailing methods cannot effectively address the pending problem of excessive hot‐spot temperature. In this paper, a radial layered structure is proposed, and each encapsulation is layered according to the ‘Huke curve’, reducing the overall temperature rise and metal consumption of the reactor significantly. Further, a combined‐constraints‐based optimization (CCBO) methodology is proposed with combined advantages of the isothermal rise method and the equal resistance voltage method. A joint solution model for the electrothermal parameters of multiple encapsulations is established. The optimal parameters combination is obtained through iterations, and the temperature rise distribution tends to be balanced. The calculation example for an 800‐kV bridge arm reactor with the radial layered structure shows that the hot spot temperature rise is 33.9% lower than that of the traditional structure, and the metal consumption decreases by 61.5%. Through the CCBO methodology, the temperature difference among encapsulations reduces by 12.5% in comparison with the isothermal rise method. From this work, encapsulations’ temperature rise distribution and their metal consumption become balanced and less, which will improve the reactors’ operation reliability.