Selection of the Technique of Arrangement of Equipment Service Area to Provide the Permissible Touch Voltage

Abstract

Ensuring the permissible value of the touch voltage in operating electrical installations is a necessary condition for the electrical safety of personnel and third parties. In the study, based on literature data, it is analyzed in which cases it is impossible to achieve the permissible values of the touch voltage only with the help of the design of the grounding system. It is shown that ensuring the permissible value of the touch voltage is performed by arranging in a special way both the place of operational maintenance of the equipment and the territory of the opendoor switchgear. It is study the selection a technique of arrangement of the service place to ensure the permissible value of the touch voltage on the equipment of the opendoor switchgear during a single-phase short circuit to the ground. When performing the work, statistical methods of analysis, the ammeter-voltmeter method for experimental determination of the resistance of the base according to the method of Research&Design institute "Molniya" NTU "KhPI" were used. For the first time, on the basis of statistical data, the necessity of arrangement of equipment service area to ensure an acceptable value of touch voltage at operating substations of class 110 (150) kV and 330 (220) kV was analyzed. The spread of base resistance (ground resistance of human foot) values was determined experimentally. The most common ways of arrangement of equipment service area were analyzed: technological (natural), namely: a reinforced concrete pool with a layer of crushed stone, a cable channel or tray, asphalt paths and specially created (artificial) ones, namely: a metal structure , a layer of crushed stone, reinforced concrete slabs, concrete slabs without scaffolding, paving slabs, concrete slabs (paving slabs) with gravel admixtures, polymer sand slabs. The base resistance was measured for the listed techniques at operating substations. The advantages and disadvantages of various arrangement of equipment service area are determined, and recommendations for their use are provided.