Protection of workers against the magnetic field of 330-750 kV overhead power lines when performing work without removing the voltage under load

Abstract

Problem. One of the acute problems that needs to be solved when performing repair work under voltage on power transmission lines (PTLs) is the protection of workers’ health from high-intensity electromagnetic fields. Goal. The purpose of the work is to develop the methodological foundations for the protection of workers from the magnetic field (MF) of the 330-750 kV PTL during repairing work without removing the voltage and under loading. Methodology. A methodology for calculating the maximum allowable PTL loading factor has been developed. It limits the flux density of the MF in the working area of the power transmission line to the maximum permissible level of sanitary standards for the given period of work at the potential and the minimum thickness of the protective layer between the wires and the worker’s body. Originality. Methodological principles for protecting workers from magnetic fields have been created. They are based on the joint use of the developed method of mode load minimization and the method of increasing the working distance, and the developed method of calculating the maximum allowable loading factor of PTLs. Practical value. The graphic dependence of the maximum allowable loading factor of the PTL is proposed as a function of the required working time and the thickness of the introduced additional protective layer between the wires and the body of the worker. It allows one quickly determines the maximum allowable loading factors to conform the accepted limit-allowable normative level of flux density of MF for various types of PTLs 330-750 kV. References 45, tables 1, figures 10.