A thermal model for calculating axial temperature distribution of overhead conductor under laboratory conditions

•Establishing model for axial conductor temperature calculation in laboratory.•Identifying non-weather related thermal parameters of different conductors.•Analysing change laws of non-weather related thermal parameters.•Measuring axial temperature of conductor by experiment platform.•Comparison of precision between thermal model and IEEE standard model. Most traditional thermal models of overhead conductor neglect the axial temperature distribution along the length of conductor. In order to provide a necessary foundation for calculating axial conductor temperature distribution in real weather conditions, a thermal model is proposed for the axial conductor temperature calculation under laboratory environment. This proposed model is established with the equivalent thermal network, and expressed as a nonlinear state-space equation. An identification method is presented to determine the conductor thermal parameters, which are non-weather related and hardly to be calculated theoretically. The interior-point algorithm is employed to optimize the objective function of parameter identification. The effectiveness of identification method and proposed thermal model are validated by experiment results. This study will provide the basic modelling principle, parameter identification method and conductor thermal parameters to develop the conductor thermal model under the real weather conditions in the future.