State evaluation technology of distribution network cable based on novel internal conductor temperature measurement

To evaluate insulation status of power cables and improve cable transmission utilization, a novel measurement and control system for intelligent cable (MCIC system) is designed and manufactured. In MCIC system, the multimode fiber is placed into cable conductor, cable connectors and terminals when power cable was manufactured in the factory. The axial temperature data of cable conductor can be measured directly in operating cable by the MCIC system platform. MCIC system has two innovative functions: dynamic calculation of power cable ampacity and regulation of electric energy in relevance region. Analysing the changing rules of environmental temperature, cable insulation temperature and corresponding current, the realtime maximum cable ampacity list can be obtained by iterative computations. According to the ampacity list, the operators can exactly acquire the real-time maximum currents every power cable line and regulate the conveying current values accurately. Furthermore, the concept of electric load balance in a region is realized in the MCIC system. Some testing data from MCIC system established in Shenzhen demonstrate that conductor temperature can quickly respond to changes in cable load, and the real-time cable carrying capacity can be online caculated.