Analysis of existing types of protection against single-phase earth faults and their application conditions

Abstract

Currently, the problem of determining a single-phase earth fault in networks with isolated and compensated neutral mode is still relevant. According to the existing data, according to the time of elimination of these technological violations, the conclusion arises, according to which the effectiveness of existing protections is called into question. This issue is particularly acute for electric grid companies that serve urban electric networks, since the mass of lines laid next to each other and the heterogeneous nature of the load makes the network mode not suitable for the use of modern protections. Therefore, as a definition of damage, the method of sequential disconnection and the method of dividing the network into sections, which were used half a century ago, are used. Therefore, the analysis of the existing earth fault protection will help to identify the existing problem more clearly, as well as set the direction for further scientific research in this area. The methodological basis, in this article, is the analysis. The information for this method is taken from the theoretical and empirical information of previously published works. In particular, the existing types of protection against single-phase earth faults are considered. Their analysis and conditions of applicability for the electric economy of urban electric networks are made. In the course of the analysis, it was found that the existing protection against single-phase earth faults can reduce the search range of OZZ, but, so far, they can not provide absolute selectivity for the conditions of urban electrical networks made by cable lines. Since such electrical networks are typical for densely populated areas, the above problem is relevant and requires a quick solution.