A Study on How to Lower the Grounding Impedance by Needles-typed Grounding Rods

doi:10.15683/kosdi.2022.3.31.019

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2022 Vol.18, Issue 1 Preview Page Next Page

Original Article

A Study on How to Lower the Grounding Impedance by Needles-typed Grounding Rods 접지침봉에 의한 접지임피던스를 낮추는 방안 연구: 박성렬*
Sung-Yeol Park*; Doctor’s Course, Department of Industrial Engineering, Sunmoon University, Asan, Republic of Korea

31 March 2022. pp. 19-28

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Abstract

Purpose: One of the methods for preventing disasters such as fire, explosion, and electric shock caused by electricity is to perform grounding. In case of the grounding current includes a frequency component having a high, it is preferable to measure grounding impedance rather than grounding resistance. This study proposes countermeasures to reduce grounding impedance to suppress an ground potential rise due to a grounding current having a frequency component of several kHz or more. Method: General grounding rods and needles-typed grounding rods were buried in the ground, and grounding resistance and grounding impedance were measured, respectively. The characteristics of grounding impedance according to frequency were identified. Result: There was little difference in the measurement results of the grounding resistance between general grounding rods and needles-typed grounding rods. In a frequency range lower than 62.5kHz, there was little difference in the measurement results of the grounding resistance between general grounding rods and needles-typed grounding rods. In a frequency range higher than 62.5kHz, the grounding impedance of needles-typed grounding rods was reduced by about 15% than the grounding impedance of general grounding rods. Conclusion: In the commercial frequency domain, it is effective to connect several grounding rods (common grounding) to lower the grounding resistance value. In the frequency domain of several kHz or more, it is expected that needles-typed grounding rods can effectively reduce the ground potential rise due to the grounding current.

Keywords

Disaster

Grounding Resistance

Grounding Impedance

Ground Potential Rise

General Grounding Rods

Needles-typed Grounding Rods

연구목적: 전기로 인한 화재·폭발·감전 등의 재해를 예방하기 위한 방법 중의 하나가 접지를 시행하는 것이다. 접지전류가 높은 주파수 성분을 포함하는 경우에는 접지저항보다는 접지임피던스를 측정하는 것이 바람직하다. 본 연구에서는 수 kHz 이상의 주파수 성분을 가지는 접지전류에 의한 대지전위상승을 억제하기 위한 접지임피던스를 줄이는 방안을 제시하고자 한다. 연구방법: 대지에 접지동봉과 접지침봉을 매설하여 각각 접지저항과 접지임피던스를 측정하였고, 주파수에 따른 접지임피던스의 특성을 파악하였다. 연구결과: 접지동봉과 접지침봉의 접지저항 측정 결과는 거의 차이가 없었다. 62.5kHz 보다 낮은 주파수 영역에서는 접지동봉이나 접지침봉의 접지임피던스 측정 결과는 거의 차이가 없었으며, 62.5kHz 보다 높은 주파수 영역에서는 접지침봉의 접지임피던스가 접지동봉의 접지임피던스보다 약 15% 정도의 저감효과가 있었다. 결론: 상용주파수 영역에서 접지저항 값을 낮추기 위하여 다수의 접지극을 공통으로 접지하는 것이 효과적이고, 접지임피던스가 낮은 접지침봉을 설치하는 경우 수 kHz 이상의 주파수 성분을 가지는 접지전류에 의한 대지전위상승을 효과적으로 억제할 수 있을 것으로 보인다.

키워드

재난

접지저항

접지임피던스

대지전위상승

접지동봉

접지침봉

References

Choi, H.K., Song, Y.J., Oh, J.S., Choi, B.S. (2018). Design of Grounding Facilities. Seongandang Press, Paju, Korea. 10.15444/GMC2018.09.04.04
Framework Act on the Management of Disasters and Safety (2020). Ministry of the Interior and Safety.
Gil, H.J., Shong, K.M., Kim, Y.S., Kim, C.M., Kim, Y.J. (2016). "Design and fabrication of high frequency ground impedance measuring system for assessment of grounding system for lightning protection." Journal of the Korean Society of Safety, Vol. 31, No. 3, pp. 47-52. 10.14346/JKOSOS.2016.31.3.47
Kim, D.S., Lee, B.H. (2019). "Potential rises on grounding grid combined with carbon ground electrodes depending on the injection point of impulse currents." Journal of KIIEE, Vol. 33, No. 1, pp. 54-60. 10.5207/JIEIE.2019.33.1.054
Kim, H.Y., Jang, U.B. (2017). "A study on the safety grounding for prevention of electric shock hazard in construction of industrial plant in maritime landfill area." Journal of the Korea Society of Disaster Information, Vol. 13, No. 1, pp. 21-27.
Kim, H.J., Kim, H.G., Lee, B.H. (2017). "Ionization characteristics of soil due to impulse voltage." Journal of KIIEE, Vol. 31, No. 6, pp. 54-62. 10.5207/JIEIE.2017.31.6.054
Kim, H.Y., Yoon, S.H. (2018). "A Study on the Safety Characterization Grounding Design of the Inner Photovoltaic System." Journal of the Korea Society of Disaster Information, Vol. 14, No. 1, pp. 1-11.
Lee, B.H., Eom, J.H. (2004). "Analysis of the frequency dependent characteristics og ground impulse of a ground rod." The Korean Institute of Electrical Engineers, Vol. 53C, No. 8, pp. 426-432.
Lee, B.H., Lee, S.C. (1999). The Major Foundational Technics for Grounding Systems. Uije Press, Seoul, Korea.
Park, C.W., Kim, H.G., Lee, B.H. (2017). "Comparison of soil needles discharge Characteristics of ground rod and ground electrode with under impulse voltage." Proceedings of KIIEE Annual Conference, Seoul, p. 69.
Seo, J.S., Park, H.C., Kil, G.S., Oh, J.G. (2013). "Comparative Analysis on Ground Impedance for a Carbon Block and a Copper Rod." J. KIEEME, Vol. 26, No. 6, pp. 472-477. 10.4313/JKEM.2013.26.6.472
Yoo, Y.W., Cho, S.C., Lee, B.H. (2014). "Effects of soil discharges on the impulsive ground impedance of ground rod with needles." Journal of KIIEE, Vol. 28, No. 5, pp. 98-105. 10.5207/JIEIE.2014.28.5.098

Information

Publisher :The Korean Society of Disaster Information
Publisher(Ko) :한국재난정보학회
Journal Title :Journal of the Society of Disaster Information
Journal Title(Ko) :한국재난정보학회논문집
Volume : 18
No :1
Pages :19-28
DOI :https://doi.org/10.15683/kosdi.2022.3.31.019

[1] Choi, H.K., Song, Y.J., Oh, J.S., Choi, B.S. (2018). Design of Grounding Facilities. Seongandang Press, Paju, Korea. 10.15444/GMC2018.09.04.04

[2] Framework Act on the Management of Disasters and Safety (2020). Ministry of the Interior and Safety.

[3] Gil, H.J., Shong, K.M., Kim, Y.S., Kim, C.M., Kim, Y.J. (2016). "Design and fabrication of high frequency ground impedance measuring system for assessment of grounding system for lightning protection." Journal of the Korean Society of Safety, Vol. 31, No. 3, pp. 47-52. 10.14346/JKOSOS.2016.31.3.47

[4] Kim, D.S., Lee, B.H. (2019). "Potential rises on grounding grid combined with carbon ground electrodes depending on the injection point of impulse currents." Journal of KIIEE, Vol. 33, No. 1, pp. 54-60. 10.5207/JIEIE.2019.33.1.054

[5] Kim, H.Y., Jang, U.B. (2017). "A study on the safety grounding for prevention of electric shock hazard in construction of industrial plant in maritime landfill area." Journal of the Korea Society of Disaster Information, Vol. 13, No. 1, pp. 21-27.

[6] Kim, H.J., Kim, H.G., Lee, B.H. (2017). "Ionization characteristics of soil due to impulse voltage." Journal of KIIEE, Vol. 31, No. 6, pp. 54-62. 10.5207/JIEIE.2017.31.6.054

[7] Kim, H.Y., Yoon, S.H. (2018). "A Study on the Safety Characterization Grounding Design of the Inner Photovoltaic System." Journal of the Korea Society of Disaster Information, Vol. 14, No. 1, pp. 1-11.

[8] Lee, B.H., Eom, J.H. (2004). "Analysis of the frequency dependent characteristics og ground impulse of a ground rod." The Korean Institute of Electrical Engineers, Vol. 53C, No. 8, pp. 426-432.

[9] Lee, B.H., Lee, S.C. (1999). The Major Foundational Technics for Grounding Systems. Uije Press, Seoul, Korea.

[10] Park, C.W., Kim, H.G., Lee, B.H. (2017). "Comparison of soil needles discharge Characteristics of ground rod and ground electrode with under impulse voltage." Proceedings of KIIEE Annual Conference, Seoul, p. 69.

[11] Seo, J.S., Park, H.C., Kil, G.S., Oh, J.G. (2013). "Comparative Analysis on Ground Impedance for a Carbon Block and a Copper Rod." J. KIEEME, Vol. 26, No. 6, pp. 472-477. 10.4313/JKEM.2013.26.6.472

[12] Yoo, Y.W., Cho, S.C., Lee, B.H. (2014). "Effects of soil discharges on the impulsive ground impedance of ground rod with needles." Journal of KIIEE, Vol. 28, No. 5, pp. 98-105. 10.5207/JIEIE.2014.28.5.098

Journal of the Society of Disaster Information ISSN:1976-2208(Print) 2671-5287(Online) 한국재난정보학회논문집

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