Inversion of soil thermal conductivity for high voltage power cable
Temperature is a predominant variable to identify the operating state of buried cables,while ampacity is a performance metric for the thermal stability limit of cables.Because power cables are laid underground,precise constitutive parameters such as soil thermal conductivity are essential and fundamental for accurate calculation of the cable temperature field.However,the thermal conductivities of cable backfill soil and mother soil are affected by cable heat dissipation,region,climate and other factors,which result in significant differences and uncertain-ties,making it relatively difficult to accurately calculate the ampacity.In order to accurately calculate the tempera-ture field and ampacity of high-voltage power cables under engineering operating conditions,this paper proposes a mathematical model and solution methodology for the real-time inversion of soil thermal conductivity for power ca-bles.First,a distributed optical fiber temperature measurement system for the outer surface temperature of cables is developed to invert the soil thermal conductivity for power cables;then,based on the real-time temperature of typi-cal sampling points on the cable skin,a mathematical model for the real-time inversion of the layered soil thermal conductivity is constructed.Finally,an improved genetic algorithm for solving the inverse problem is proposed.The numerical results show that the real-time or dynamic ampacity calculated using the proposed methodology is about 38.08％ higher than the nominal ampacity.
inverse problemimproved genetic algorithmfinite element methodthermal conductivity
万方数据
维普
