Principles of protection against single phase earth faults in networks with capacitive current compensation

Navoi State University of Mining and Technologies, Navoi, Uzbekistan

^* Corresponding author: muxammadov.bobur@mail.ru

Abstract

Protections that respond to a constant operating current applied to the network. This principle allows, in addition to the protection itself, continuous monitoring of insulation defects. But the imposition of direct current on the network is common only in networks with a voltage below 1000 V. In relation to 3-35 kV networks, the applied direct current is not used, in particular, due to the fact that the possibility of individual blind grounding of several neutrals of the primary windings of voltage measuring transformers, which can be installed at different substations of the network, is excluded. The protection with the imposition of direct current has most of the elements in galvanic connection with the generator voltage system, which, of course, reduces operational reliability. Moreover, grounding the system can lead to catastrophic consequences. The use of this method is also limited by the fact that special transformers must be installed at each connection, which in turn is very expensive.