466 / 2017-05-07 10:33:35

Simulation of numerical calculation method for carrying capacity of urban underground cable group

carrying capacity;cable group;numerical calculation

The calculation of the ampacity of underground cable group can effectively determine the ampacity of power cable under the specific environmental conditions. Numerical prediction of cable carrying capacity, the need for conversion of electrical parameters, the thermal parameters of the cable layer, which gives the calculation results of cables of temperature field and flow field parameters, predict the load flow numerical calculation. The total loss of the equivalent thermal resistance and cable traditional method according to different parts of the cable thermal circuit calculation, determine a plurality of different load conditions but ignores the coexistence of cable, the calculation of relevant parameters of temperature field and flow field, the forecast precision is relatively low. According to the power cable of city power grid row pipe laying group, from heat conduction, heat convection and heat three aspects to analyze the heat transfer process of radiation, combined with a 220kV cable and 35kV cable duct laying with the actual conditions, set up a two-dimensional finite element model of temperature field and flow field. The cable was converted thin electrical parameters, thermal parameters using multi-layer cylindrical structure, carrying capacity under the condition of a certain 220kV cable was calculated, the calculation results of temperature field and flow field of cables are given, and further from the soil thermal conductivity, temperature and load of adjacent cable of three aspects of the quantitative effects of the current carrying capacity of cable factor calculation.