On the system of ensuring electrical safety of maintenance works performed on 35 – 750 kV power transmission lines being under induced voltage implemented in the Republic of Belarus

The article studies the matters of physics of interaction of parallel overhead power transmission lines. Cases are presented, where the maximum induced voltage values are expected on individual sections of closely approaching de-energized and energized power transmission lines. Possible scenarios are presented of direct contact with an unearthed conductor (wire) of OPL in the normal operation mode. Substantiation is presented of review of the list of the lines, which, when de-energized or earthed at terminal sections (in the switchgear of substations and power plants) have the values of induced voltage on the earthed conductors, as reduced to the maximum permissible continuous current of the affecting OPL, exceeding 25 V . Criteria are identified to classify OPL as being affected by induced voltage. The article considers organizational and technical procedures applied to provide safe maintenance works under induced voltage on de-energized overhead power lines (OPL) located within an area affected by energized OPL.  Attention is given to the detailed description of types of earthing of OPL, line equipment, working section and workplaces used by State Production Association Belenergo. The mathematical apparatus used in the analytical calculations of the induced voltage values has been analyzed. The technical implementation of acceptable schemes of performing the repair and maintenance works on the earthing of de-energized OPL is considered. Performing geophysical ground survey by the method of vertical electrical sounding at places of mounting special low-resistance earthing electrodes is proposed and implemented. The methodology is developed and tested for measuring induced voltage values, which sets the order of induced voltage measurements on de-energized OPL running close to energized OPL with the voltage 110 kV, and higher. Comparative analysis is presented of results of analytical calculations and experimental research. Conclusions are made supporting the approach adopted and confirming the expediency of the system of ensuring electrical safety of maintenance works performed on 35–750 kV power transmission lines being under induced voltage implemented in the Republic of Belarus.

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