Parameter identification for current–temperature relationship of contact wire under natural convection

Abstract The current–temperature relationship of contact wire in high-speed railways is the key to the design of pantograph–catenary system and operational planning of electrified locomotives. The traditional researches on the current–temperature relationship of bare overhead conductors and model parameters mainly focus on aluminum conductor steel reinforced (ACSR), while the description of the heat balance process of contact wire is relatively lacking. In this paper, by optimizing the features of the existing models, an electro-thermal coupling (ETC) model is established to describe the current–temperature relationship under different convection conditions. For the unknown parameters in this model, a parameter identification method based on the nonlinear primal–dual interior point algorithm is applied. The effectiveness of the parameter identification method and the ETC model is verified by the current–temperature experiment of contact wire under different current levels. The experimental results show that the root mean square error of the ETC model using identified parameters is only 1.22%, which demonstrates that the parameter identification method can effectively obtain the model parameters under natural convection. On this basis, a comparison shows that the root mean square error of the ETC model is 6.81% lower than that of the IEEE model, which demonstrates that the ETC model can describe the current–temperature relationship of contact wire under natural convection more accurately after parameter identification.