A novel transient thermal circuit model of buried power cables for emergency and dynamic load

Abstract

In order to improve the utilization rate of cable while ensuring safety and reliability, accurate and rapid evaluation of transient temperature rise of directly buried power cables is useful to improve the management level of dynamic capacity increase and emergency load conditions. Since the existing thermal circuit model is relatively complex or not very accurate, an equivalent three-branch transient thermal circuit model is presented for the complex cable structure and heat dissipation environment based on the uniqueness of the temperature field. Considering the electric circuit similarity, the transient analysis method of the centralized parameter network in the circuit is used to establish the transient adjoint model of the thermal capacity branch, provide the node conduction matrix of the transient thermal circuit model, and write the node temperature rise equation as a function of the node heat flow. By comparing the solution of the thermal circuit model with the finite element results, and the genetic algorithm is used to optimize and obtain the equivalent thermal resistance and thermal capacity parameters of the transient thermal circuit model. The comparison of finite element calculation results proves that the proposed three-branch transient thermal circuit model is more accurate than the two-branch thermal circuit model. Compared to the traditional all-part thermal circuit model, the three-branch model can be rapidly solved and easily applied in engineering.