The concept of building protection of electric networks 380 V signal-phase shortcircuit

The subject of study of this work is to improve electrical safety in networks 380V neutral to earth type TN-C single-phase short-circuit on the neutral conductor and the associated metal structures. According to the analysis of accident statistics overhead lines with bare wires are the least reliable element of the electric network - 62 % of the damage they are dangerous to people and animals. This article is a brief review of the literature and the urgency of the development of methods of calculation, selection and placement of fuses and circuit breakers along the protected line, which would provide 100 % of the area to protect it. Considered in the design concept of the article protect electrical grids of 380 neutral to earth is the partitioning along the overhead lines fuses and circuit breakers. The concept of construction is shown by the example of security VL-0,38 kV 500 m long and a section of 35 mm square, which is powered by a transformer rated 160 kVA with a connection scheme Y/YH and protected by fuses with different rated currents. Graphic shows the dependence such as the change in the ratio of sensitivity to length line, changing the zone of protection, depending on the current fuse links for various electrical parameters, etc. These relationships allow us to determine the place of installation of fuses or circuit breakers to ensure the absence of a failure of protection zones in response time less than 5 seconds. Research results will be used to build the security of simple trunk and branches with a widely used taps overhead line voltage of 380 V.