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Analyzing and identifying the limits of 660V grid parameters to ensure electrical safety in underground coal mines

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Authors:


Le Xuan Thanh, orcid.org/0000-0001-5052-4484, HaNoi University of Mining and Geology, HaNoi, Socialist Republic of Vietnam, e-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.

Ho Viet Bun, orcid.org/0000-0003-2123-9179, HaNoi University of Mining and Geology, HaNoi, Socialist Republic of Vietnam, e-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.


повний текст / full article



Naukovyi Visnyk Natsionalnoho Hirnychoho Universytetu. 2021, (6): 101 - 106

https://doi.org/10.33271/nvngu/2021-6/101



Abstract:



Purpose.
To study the relation between leakage current and time, then to identify some limits of grid parameters to ensure electrical safety as well as explosion safety corresponding to all operating modes of leakage relay in Vietnam underground mines.


Methodology.
In underground coal mines of Vietnam, 660 V grids are characterized by ungrounded neutral point electric system. They require very serious and strict operation conditions including electrical safety and explosion safety. In daily operation, the earth leakage currents (earth fault currents) must be lower than the allowance limit. However, when utilizing many new power electronic devices such as variable speed drive (VSD), the quantity of connected equipment changes due to the change in capacitance current. After measuring the grid parameters, leakage currents are computed in terms of 3 compensating levels of earth fault relays. The resulting values of currents are used to build up limit curves.


Findings.
Curves of the graphs present the relation between the leakage current and the length of transmission cables associated with various connecting equipment. The curves may be used to operate the electric system safely and effectively.


Originality.
The proposed equations and simulation in Matlab may be applied to all underground mining grids with different input parameters.


Practical value.
Operating curves of the graphs are used to identify the most suitable grids parameters which could ensure electrical safety (keeping the leakage current within the allowance limits). It could help operators or technicians optimize the structure of grid and ensure its safety.



Keywords:
660 V grid, ungrounded neutral point, electrical safety, protection relay, coal mines

References.


1. VINAMCOMIN (2019). Orientation for sustainable development of coal mining. Approved by Priminister Dicision No 403/2016/Q-TTg. Retrieved from http://www.vinacomin.vn/dinh-huong-phat-trien-ben-vung-nganh-than-viet-nam-gan-voi-dam-bao-an-ninh-nang-luong/dinh-huong-phat-trien-ben-vung-nganh-than-viet-nam-gan-voi-dam-bao-an-ninh-nang-luong-201901181507032041.htm.

2. Hufnagi, E., Fickert, L., & Schmautzer, E. (2015). Efficient Calculation of earth fault currents in compensated networks. Power engineering, 1-17. Retrieved from http://ke.powerlab.um.si/Arhiv/dokument.aspx?id=178.

3. Gao, Y., Ma, F.L., Dong, G.Z., & Xing, H.L. (2014). Research on Centralized Short-circuit and Leakage Protection for High-voltage System of Underground Central Substation. Applied Mechanics and Materials, (494), 1753-1757. https://doi.org/10.4028/www.scientific.net/AMM.494-495.1753.

4. Niculescu, T., Arad, V., Marcu, M., Arad, S., & Popescu, F.G. (2020). Safety barrier of electrical equipment for environments with a potential explosion in underground coal mines. Mining of Mineral Deposits, 14(3), 78-86. https://doi.org/10.33271/mining14.03.078.

5. Qi, X., Lo, S.C., Gyure, A., Luo, Y., Shahram, M., Singhal, K., & MacMillen, D.B. (2006). Efficient subthreshold leakage current optimization-Leakage current optimization and layout migration for 90- and 65-nm ASIC libraries. IEEE Circuits and Devices Magazine, 22(5), 39-47.

6. TCVN 6780-4, 2009, Ministry of Industry National Technical safety Regulation on Underground mines (n.d.). Retrieved from https://tieuchuan.vsqi.gov.vn/tieuchuan/view?sohieu=TCVN+6780-4%3A2009.

7. Wymann, T., Pollock, M., & Rees, J. (2015). A new approach to mining earth leakage protection with medium voltage drives. Industrial-Electrix, 24-27. Retrieved from https://library.e.abb.com/public/581ec6f4334847f1a83e4ee8f693589a/MESC_ELR%20Paper_9AAK10103A3924_RevA.pdf.

8. Bottrill, G., Cheyne, D., & Vijayaraghavan, G. (2005). Practical electrical equipment and installations in hazardous areas. Elvisier press. https://doi.org/10.1016/B978-0-7506-6398-4.X5000-9.

9. Nguyen, K.T., Kim, L.N., Nguyen, S.T., & Nguyen, G.T. (2020). Research, design, manufacture leakage current protection device for 660 V/1140 V underground mine electrical networks. Journal of Mining and Earth Sciences, 61(5), 96-103. https://doi.org/10.46326/jmes.2020.61(5).11.

10. Tuan, N.G., & Tien, N.H. (2020). Research for determining insulation factors of 600V underground mining in area of Hon Gai. Journal of Automation Today. Retrieved from https://vnautomate.net/nghien-cuu-xac-dinh-cac-thong-so-cach-dien-so-voi-dat-cua-mang-ha-ap-660v-mo-than-ham-lo-vung-hon-gai.html.

11. Coal Mining Safety and Health Regulation 2017, Part 4 Electrical activities, equipment and installations (n.d.). Retrieved from https://www.legislation.qld.gov.au/view/pdf/asmade/sl-2017-0165.

12. Safety Standards for Electrical Installations and Equipment in explosives facilities, JSP 482 MOD Explosives Regulations (2016). Retrieved from https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/529168/20160526-JSP_482_Edt4_1_Chapter_8.pdf.

13. Vietnam National regulation on safety Mining, QCVN 01:2011/BCT (2011). Retrieved from http://www.kiemdinh.vn/upload/files/QCVN%2001-2011-BCT%20An%20toa%CC%80n%20trong%20khai%20tha%CC%81c%20than%20h%C3%A2%CC%80m%20lo%CC%80.pdf.

14. Velimir Lackovic, Grounding system Theory and Practice, CED-Continueing Education and Development, Inc, Course E04-027 (n.d.). Retrieved from https://www.cedengineering.com/userfiles/Grounding%20System%20Theory%20and%20Practice%20R1.pdf .

15. Qiang, C., Ning, C., & Zhen-Shuang, L. (2013). Grounding Effect on Common Mode Interference of Underground Inverter. Telkomnika Indonesian Journal of Electrical Engineering, 11(9), 5187-5194. https://doi.org/10.11591/telkomnika.v11i9.3267.

16. Remash, B. (2004). Practical power system protection. Mine underground distribution protection, 184-196. Retrieved from https://www.globalspec.com/reference/38528/203279/chapter-12-mine-underground-distribution-protection.

17. AMPCONTROL (2013). Mining earth leakage protection with variable speed drives. Retrieved from https://ampcontrolgroup.com/mining-earth-leakage-protection-with-variable-speed-drives/.

 

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ISSN (print) 2071-2227,
ISSN (online) 2223-2362.
Journal was registered by Ministry of Justice of Ukraine.
Registration number КВ No.17742-6592PR dated April 27, 2011.

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