MODELING OF ELECTROMAGNETIC FIELDS CREATED BY POWER LINES AT CUTTING THE PHASE WITH CLOSING TO THE EARTH

Abstract. High-voltage power lines  generate electromagnetic fields (EMF) in the space surrounding the wires. Analysis of EMF stresses is usually carried out at a normalized height of 1.8 m in the protected area of power lines. In symmetrical operating modes levels EMF voltages generated by power lines 110-220 kV, usually do not exceed the permissible values. However, in operating practice, there may be extreme situations in which the levels of tensions significantly increase. Such regimes are characterized, as a rule, by significant transverse and longitudinal asymmetries. Therefore, for the analysis of such modes and created at the same time EMF is advisable to use phase coordinates.

The article investigates the conditions of electromagnetic safety on the route of high-voltage power lines at phase breakage with a short circuit to the ground. Such modes are quickly eliminated by relay protection and can not have a noticeable negative impact on the staff. However, as a result of the generation of such fields, dangerous induced voltages may appear on adjacent power and communication lines. In addition, induced voltages can damage low-voltage wired equipment.

As a result of modeling in the software package Fazonord shown that the breakage of one of the phases short to ground fault leads to a substantial increase of the intensities of the electromagnetic field under wires of the transmission line normalized to a height of 1.8 m. In particular, the maximum value of the amplitude of the magnetic field increases more than 15 times.