Consideration of the Discreteness of the Parametric Series of 10 kV Overhead Line Wire Cross-Sections in Design Problems

Abstract

The article analyzes and justifies the necessity to take into account the discreteness of the parametric series of wire cross-sections of 10 kV overhead lines in the process of designing electrical networks. The analysis of the parameters of 10 kV overhead lines was performed for electrical networks of the Eastern part of Ukraine under the condition of the appearance of the current density on the line section as a random variable. The inexpediency of using economic current density as the main optimization parameter that characterizes and determines one or another line option during design is shown. It is proven that in order to accept the economic current density as the optimal parameter, its value must be maintained across all sections of the network, which is practically impossible due to the discreteness of the parametric series of wire cross-sections and the change in load in the electrical network. The cross-section of the wires is proposed as an optimization parameter that characterizes and determines a particular line option. For this purpose, technical and economic model of 10 kV overhead lines was improved and analyzed using the criterial method. According to the results of the analysis, it was determined that, depending on the error of the initial information, in the first approximation, the coefficient of increase of the parametric series of wire cross-sections of 10 kV overhead lines at level 2 is the most acceptable. Statistical series are constructed for the distribution of the wire cross-section as a random variable. To determine the interval of the relative cross-section of the wires of 10 kV overhead lines, it is assumed that the law of change in the density of the distribution of wire cross-sections is quite close to the normal distribution law. When testing the proposed hypothesis using the Pearson criterion and variance estimation, it was found that this hypothesis does not contradict real data, which justifies the cross-section of 10 kV overhead lines as an optimization parameter that characterizes and determines one or another line option when designing electrical networks.