| Title |
A Method for Evaluating Electric Shock Hazards Based on Human Body Current |
| Authors |
Bok-Hee Lee ; Yang-Woo Yoo ; Jong-Hyuk Choi |
| DOI |
http://dx.doi.org/10.5207/JIEIE.2011.25.6.108 |
| Keywords |
Electric Shock Hazard ; Ground Surface Potential Rise ; Human Body Current ; Touch Voltage ; Step Voltage ; Two-Layer Soil Structure |
| Abstract |
In order to mitigate the possible hazards from electric shock due to the touch and step voltages, the high resistivity material such as gravel is often spread on the earth"s surface in substations. When the grounding electrode is installed in two-layer soil structures, the surface layer soil resistivity is different with the resistivity of the soil contacted with the grounding electrodes. The design of large-sized grounding systems is fundamentally based on assuring safety from dangerous voltages within a grounding grid area. The performance of the grounding system is evaluated by tolerable touch and step voltages. Since the floor surface conditions near equipment to be grounded are changed after a grounding system has been constructed, it may be difficult to determine the tolerable touch and step voltage criteria. In this paper, to propose an accurate and convenient method for evaluating the protective performance of grounding systems, the propriety of the method for evaluating the current flowing through the human body around on a counterpoise buried in two-layer soils is presented. As a result, it is reasonable that the grounding system performance would be evaluated by measuring and analyzing the current flowing through the human body based on dangerous voltages such as the touch or step voltages and the contact resistance between the ground surface and feet. |