Determination of the Optimal Working Conditions of Cable Lines in an Underground Cable Channel

摘要

Mathematical modeling of heat transfer processes inside a cable channel taking into account natural convection and radiation between the cable surface and tube and the loss in shields was carried out. An underground cable channel consisting of eight lines with a voltage of 6 kVand six lines with a voltage of 35 kV was investigated. The conductor section is 150 mm2. Cables of APvVng-LS brand were placed in a triangle inside polyethylene tubes. The patterns of temperature fields obtained under variance of different various factors were determined, the permissible currents were calculated, and the optimal circuits of connection of cable lines depending on the selected criterion were proposed. The two-dimensional nonstationary problem of complicated heat and mass transfer and heat conductivity inside the underground cable channel was solved by the finite elements method using the AN SYS software package. The range of permissible operating currents depending on the location of cable lines and priority of their connection was determined. The effect of the temperature of the environment on the permissible current was considered. The optimal ranges of thermal permissible currents taking into account the shield loss were calculated. The optimal connection circuits of the cable lines depending on the problem being solved were obtained. An estimation of transferred power for every considered connection method is presented. Conclusions for practical application of the method of connection of the cable line were drawn. The fields of application of this mathematical model were proposed.