Calculation of distribution cable steady and transient temperature field in ducts

With the increasing consumption of power cable in urban areas, its ampacity becomes a hot research spot. At present, lots of researches about ampacity and temperature field concentrate on one single-core cable. However, pluralities of cables are laid intensively in duct banks for a real power system. Compared to single cable, if several cables are running at the same time, those cables´ temperature and ampacity are affected by each other leading to low ampacity. Usually, existing ampacity standards are formulated by experience and not comprehensive enough for different regions. Therefore, it´s a huge and urgent demand to determine transient temperature field distribution of different laying theoretically. In this paper, in order to meet the huge demand, a temperature field model of cable group is worked out via the finite element method (FEM) and calculated by load current curves in real power system. Dispatcher and maintenance personnel can determine the ampacity reasonably to ensure safety for dispatching and management.