Radial thermal circuit model for overhead conductors based on parameter identification under natural convection condition

Ampacity, sag, creep and annealing of overhead high-voltage conductors are influenced by the radial temperature distribution. In this paper, a radial thermal circuit model in the form of state equation is established, and parameters are identified by linear regression method. Polynomial relationships between current level and model parameters are fitted based on the identification result. A radial temperature experimental platform is designed to measure the temperature rise process of ACSR400/35 conductor under natural convection condition. The comparison between calculation and experimental results reveal that the errors of radial thermal circuit model are less than 3%; study based on a 3-bus system indicates that the proposed model provides a more conservative estimate for power dispatching. Thus, it´s believed that the proposed model is more suitable for estimating radial temperature distribution of conductors under natural convection condition.