Research on fast calculation method of temperature field of metal structure near reactors considering the effect of multiple harmonic superposition

The arm reactor is an essential piece of equipment in the flexible DC transmission system. The current waveform is complex, and the harmonic content is high during the operation; therefore, the superposition of multiple harmonics must be considered for the accurate analysis of the temperature rise of structural components near the bridge arm reactor. In order to improve the calculation efficiency of temperature distribution, a fitting method is proposed to construct the frequency characteristic curve and calculate the eddy current loss under each harmonic based on the frequency variation characteristic of the reactor structure. The loss calculation error of the above method is within 2% as verified by finite element simulation calculations. Based on the proposed eddy current loss calculation method, this study calculates the temperature field of a reactor and its nearby structural components, compared to the traditional method of calculating the loss by summing each harmonic individually, the proposed approach achieves a temperature error of less than 3% and the calculation efficiency is increased by 73.3%. The loss calculation method proposed in this paper can provide guidance and reference for the rapid calculation of temperature field of nearby structural components of reactors.