The Choice of a Construction Arrangement for Cable Lines with a Voltage of 10 kV According to the Criterion of the Minimum Expected Cost

The article considers the issue of choosing the optimal construction arrangement of cable lines with a voltage of 10 (20, 35) kV with cross-linked polyethylene insulation. The options for using three or single-core cables laid in a triangle or in a plane are analyzed. The methodological basis of the work is the principle of minimizing the expected costs, taking into account both capital investments and annual costs, including losses of electrical energy in cables. Within the framework of the study, a nomogram of economic intervals was scheduled, which makes it possible to determine the optimal cable core sections and boundary conditions for the use of threeand single-core cables, depending on the calculated current load. It is shown that with the existing nomenclature of three-core cables with a maximum core cross-section up to 630 mm 2 , single-core cables can be economically feasible only with a core cross-section of 800 mm 2 and above. It has been discovered that the expected costs for laying single-core cables in the plane with two-way grounding of screens always turn out to be higher than when laying a triangle. This effect is due to an increase in both capital costs and power losses in cable screens. To increase the efficiency of cable lines, it is proposed to expand the range of three-core cables by including cables with the maximum possible core cross-section. This will make possible to increase the range of current loads in which the use of three-core cables will be economically justifiable. The results presented in the article can be used in the design of new cable lines, the analysis of the effectiveness of existing ones, as well as in the modernization and reconstruction of urban medium-voltage cable networks.