| Title |
Measurement and Analysis of Risk Voltages by Various Current Sources in Grounding System |
| Authors |
길경석(Kil, Gyung-Suk) ; 문병두(Moon, Byoung-Doo) ; 김황국(Kim, Hwang-Kuk) ; 박대원(Park, Dae-Won) ; 길형준(Gil, Hyoung-Jun) |
| Keywords |
Grounding System ; Ground Potential Rise (GPR) ; Risk Voltage ; Touch Voltage ; Step voltage |
| Abstract |
Grounding systems set the reference voltage level of electric circuits and suppress the Ground Potential Rise (GPR) by flowing fault currents to the ground safely. There are several parameters which evaluate the performance of grounding systems as ground resistance, touch voltage and step voltage. The touch and step voltages, which is called "risk voltage", are especially important to ensure the safety of human body. This paper dealt with the influence of current sources with the different frequency components on the touch and the step voltages. Three types of current sources as commercial frequency, square wave, and surge with the fast risetime of 50 ns~500 ns were used to analyze the risk voltages in a grounding system. The risk voltages showed remarkable difference in the same current amplitude depending on the current sources, and increased linearly with the current amplitude in the same current source. From the experimental results, it was confirmed that the risk voltages can be evaluated by a small current application in large-scale grounding systems and the possible largest risk voltage can be calculated by a surge current with the risetime of 200 ns or a current source with the same frequency component as the surge current. |