МОДЕЛИРОВАНИЕ ПЕРЕХОДНОГО ПРОЦЕССА В РАСПРЕДЕЛИТЕЛЬНОЙ СЕТИ 10 КВ ПРИ ОДНОФАЗНОМ ЗАМЫКАНИИ НА ЗЕМЛЮ

Abstract

Relevance At the moment, finding single-phase earth faults in networks with isolated and compensated neutral is still a problem with ambiguous solutions. Existing earth fault protection devices are relevant only in special cases. In networks with a large number of outgoing connections and an extensive circuit, these protections are not able to provide absolutely selective triggering. Therefore, this problem is especially relevant for urban electric networks, since these networks are characterized by both the mass of lines and the heterogeneous nature of the load. Also, the difficulty in detecting damage is the secrecy of the transmission lines, since in these networks they are mainly made by cables. To unambiguously determine the earth fault, in urban distribution networks, earth fault protection is most often used in conjunction with the sequential shutdown method. The use of this method greatly facilitates the determination of an earth fault, but at the same time it is destructive in relation to the power supply of consumers. Since urban distribution networks supply densely populated areas with electric energy, this disadvantage further exacerbates the existing problem. In order to limit these negative consequences, it is possible to make switches by regrouping the network into sections. Such switching will allow you to quickly identify a damaged line and eliminate short-term disconnections of consumers during the search for a ground fault. However, the application of this method is accompanied by switching in the distribution network during a single-phase earth fault. Therefore, it is necessary to study the transient process that occurs during such switching in 10 kV distribution networks in order to verify the applicability of such switching. Also, this study will set the vector for further scientific research in this area. Aim of research Simulation of the transient process that occurs when combining 10 kV networks for parallel operation during a single-phase earth fault. Research methods The methodological basis in this article is mathematical simulation modeling. Results Overvoltages arising during switching in a 10 kV network during a ground fault are considered. Their analysis and the conditions of applicability of the switches performed when determining the earth fault in distribution cable networks are carried out.