Research on safe power threshold of radio wave explosion-proof in coal mine
-
摘要: 为防止煤矿井下无线设备发射的无线电波引起瓦斯爆炸,需限制煤矿井下无线电波的功率和能量。介绍了不同标准中规定的连续无线电波防爆安全功率阈值:① GB/T 3836.1—2021《爆炸性环境 第1部分:设备 通用要求》和国际标准IEC 60079-0:2017《Explosive atmospheres-Part 0:Equipment-General requirements》参考了欧洲标准CLC/TR 50427:2004《Assessment of inadvertent ignition of flammable atmospheres by radio-frequency radiation-Guide》的相关内容,省去了当爆炸性环境中不存在能作为接收天线的细长结构物体(如起重机)时,I类环境(代表性气体为甲烷)中连续无线电波防爆安全功率阈值为8 W这一条款,并不加区分地规定I类环境中连续无线电波防爆安全功率阈值为6 W;② 英国标准BS 6656:1991《Guide to prevention of inadvertent ignition of flammable atmospheres by radio-frequency radiation》规定I类环境中连续无线电波工作频率大于30 MHz时,无论是否有起重机等细长环形结构物体,连续无线电波防爆安全功率阈值均为8 W;③ 英国标准BS 6656:2002《Assessment of inadvertent ignition of flammable atmospheres by radio-frequency radiation-Guide》及欧洲标准CLC/TR 50427:2004均规定没有起重机等细长环形结构物体的I类环境中连续无线电波防爆安全功率阈值为8 W,有起重机等细长环形结构物体的I类环境中连续无线电波防爆安全功率阈值为6 W。分析了煤矿井下环境和设备特点:煤矿井下一般没有起重机;煤矿井下为受限空间,巷道较长,但巷道断面较小;沿巷道轴向敷设的电缆、水管、铁轨、钢丝绳、架空线、胶带架等轴向导体细长,但不会形成利于无线电波接收的环形天线;巷道工字钢支护等横向导体可以形成利于无线电波接收的环形天线,但工字钢导体截面大,不满足细长结构特征;综采工作面液压支架可以形成环形结构,但液压支架千斤顶将其分为多个环形结构,支架导体截面大,不满足细长结构特征。指出了煤矿井下连续无线电波防爆安全功率阈值没有执行6 W之前,漏泄、感应、透地、多基站等矿井无线通信系统已广泛应用煤矿井下,未见有引起瓦斯和煤尘爆炸事故的案例。因此,不加区分地将煤矿井下无线电波防爆安全功率阈值定为6 W,缺乏理论分析和实验验证。特别是5G,WiFi6,UWB,ZigBee等矿用移动通信系统及人员和车辆定位系统工作频率较高,因此煤矿井下连续无线电波防爆安全功率阈值应为8 W。Abstract: In order to prevent gas explosion caused by radio waves emitted by wireless equipment in the coal mine, the power and energy of radio waves in coal mines should be limited. This paper introduces the safety power threshold of continuous radio wave explosion-proof specified in different standards. ① GB/T 3836.1-2021 Explosive atmospheres-Part 1: Equipment-General requirements and the international standard IEC 60079-0:2017 Explosive atmospheres-Part 0: Equipment-General requirements refer to the European standard CLC/TR 50427:2004 Assessment of inadvertent ignition of flammable atmospheres by radio-frequency radiation-Guide. When there is no slender structure object (such as a crane) that can be used as a receiving antenna in an explosive environment, the clause that the explosion-proof safety power threshold of continuous radio wave in Class I environment (representative gas is methane) is 8 W is omitted. It is indiscriminately stipulated that the safe power threshold of continuous radio wave explosion-proof in Class I environment is 6 W. ② The British Standard BS 6656:1991 Guide to prevention of inadvertent ignition of flammable atmospheres by radio-frequency radiation specifies that for continuous radio-wave operating frequencies greater than 30 MHz in a Class I environment, the safe power threshold for continuous radio-wave explosion-proof is 8 W, Whether there is a crane or other slender annular structure object. ③ The British Standard BS 6656:2002 Assessment of inadvertent ignition of flammable atmospheres by radio-frequency radiation - Guide and the European Standard CLC/TR 50427:2004 both specify a safety power threshold of 8 W for continuous radio-wave explosion-proof in Class I environments without slender annular structures such as cranes. The safe power threshold of continuous radio wave explosion-proof in Class I environment with slender annular structures such as cranes is 6 W. The characteristic of the underground environment and equipment in the coal mine are analyzed. Generally, there is no crane underground. The underground coal mine is a confined space, with a long roadway but a small roadway section. Cable, water pipe, rail, steel wire rope, overhead line, tape rack and other axial conductors laid along the roadway axis are thin and long, but will not form a ring antenna conducive to radio wave reception. Transverse conductors such as roadway I-beam support can form a ring antenna conducive to radio wave reception. However, the section of the I-steel conductor is large, which does not meet the characteristics of slender structure. The hydraulic support in the fully mechanized working face can form an annular structure. However, the hydraulic support jack divides it into multiple annular structures. The support conductor section is large, which does not meet the characteristics of slender structure. It is pointed out that before the explosion-proof safety power threshold of continuous radio wave in coal mine is implemented to 6 W, the mine wireless communication systems such as leakage, induction, through-the-ground and multi-base stations have been widely used in the coal mine. And there is no case of gas and coal dust explosion accident. Therefore, the threshold of explosion-proof safety power of radio wave in the coal mine is set as 6 W without distinction, which lacks of theoretical analysis and experimental verification. In particular, 5G, WiFi 6, UWB, ZigBee and other mining mobile communication systems and personnel and vehicle positioning system working frequency is higher. Therefore, the coal mine continuous radio wave explosion-proof safety power threshold should be 8 W.
-
表 1 GB/T 3836.1—2021规定的连续无线电波防爆安全功率阈值
Table 1. Explosion-proof safety power threshold of continuous radio wave specified in GB/T 3836.1-2021
设备类别 连续无线电波防爆
安全功率阈值/W热起燃时间
(平均时间)/μsI 6 200 IIA 6 100 IIB 3.5 80 IIC 2 20 III 6 200 表 2 GB/T 3836.1—2021规定的脉冲式无线电波防爆安全能量阈值
Table 2. Explosion-proof safety energy threshold of pulsed radio wave specified in GB/T 3836.1-2021
设备类别 脉冲式无线电波防爆安全能量阈值/μJ I 1 500 IIA 950 IIB 250 IIC 50 III 1 500 表 3 CLC/TR 50427:2004规定的不同爆炸性气体环境类别的代表性气体
Table 3. Representative gases of different types of explosive gas environments specified in CLC/TR 50427:2004
环境类别 代表性气体 I 甲烷 IIA 丙烷 IIB 乙烯 IIC 氢气 表 4 CLC/TR 50427:2004中规定的连续无线电波防爆安全功率阈值
Table 4. Explosion-proof safety power threshold of continuous radio wave specified in CLC/TR 50427:2004
环境类别 连续无线电波防爆
安全功率阈值/W热起燃时间
(平均时间)/μsI 6(对于细长结构,例如起重机);
8(对于其他所有结构)200 IIA 6 100 IIB 3.5 80 IIC 2 20 表 5 BS 6656:1991中规定的不存在起重机时的连续无线电波防爆安全功率阈值
Table 5. Explosion-proof safety power threshold of continuous radio wave in the absence of crane as specified in BS 6656:1991
环境类别 连续无线电波防爆安全功率阈值/W I和IIA 8 IIB 4 IIC 2 注:假设源阻抗为3 000 Ω。 表 6 BS 6656:1991中规定的存在起重机时的连续无线电波防爆安全功率阈值
Table 6. Explosion-proof safety power threshold of continuous radio wave in the presence of crane as specified in BS 6656:1991
环境类别 连续无线电波防爆安全功率阈值/W I和IIA 6 IIB 3.5 IIC 2 注:假设源阻抗为7 500 Ω;连续无线电波工作频率为30 MHz以下。 -
[1] EXCELL P S, BUTCHER G H, HOWSON D P. Towards a safety standard for radiofrequency hazards to flammable mixtures—progress and problems[C]. IEEE International Symposium on Electromagnetic Compatibility, San Diego, 1979: 1-5. [2] BURSTOW D J,LOVELAND R J,TOMLINSON R,et al. Radio frequency ignition hazards[J]. Radio and Electronic Engineer,1981,51(4):151-169. doi: 10.1049/ree.1981.0021 [3] HOWSON D P,EXCELL P S,BUTCHER G H. Ignition of flammable gas/air mixtures by sparks from 2 MHz and 9 MHz sources[J]. Radio and Electronic Engineer,1981,51(4):170-174. doi: 10.1049/ree.1981.0022 [4] ROSENFELD J L J,STRACHAN D C,TROMANS P S,et al. Experiments on the incendivity of radio-frequency,breakflash discharges (1.8-21 MHz c. w. )[J]. Radio and Electronic Engineer,1981,51(4):175-186. doi: 10.1049/ree.1981.0023 [5] MADDOCKS A J,JACKSON G A. Measurements of radio frequency voltage and power induced in structures on the St Fergus gas terminals[J]. Radio and Electronic Engineer,1981,51(4):187-194. doi: 10.1049/ree.1981.0024 [6] ROBERTSON S S J,LOVELAND R J. Radio-frequency ignition hazards:a review[J]. Physical Science,Measurement and Instrumentation,Management and Education-Reviews,IEE Proceedings A,1981,128(9):607-614. [7] EXCELL P S,MADDOCKS A J. Assessment of worst-case receiving antenna characteristics of metallic industrial structures. Part 1:Electrically-small structures[J]. Journal of the Institution of Electronic and Radio Engineers,1986,56(1):27-32. doi: 10.1049/jiere.1986.0006 [8] EXCELL P S,HOWSON D P. Assessment of worst-case receiving antenna characteristics of metallic industrial structures. Part 2:Electrically-large structures[J]. Journal of the Institution of Electronic and Radio Engineers,1986,56(1):33-36. doi: 10.1049/jiere.1986.0008 [9] JAMES R A,EXCELL P S,KELLER A Z. Probabilistic factors in radio-frequency ignition and detonation hazards analyses[J]. Reliability Engineering,1987,17(2):139-153. doi: 10.1016/0143-8174(87)90012-6 [10] EXCELL P S,JAMES R A,KELLER A Z. Strategic problems in the drafting and implementation of safety guides for the prevention of radio frequency radiation hazards[J]. International Journal of Quality & Reliability Management,1988,5(5):47-61. [11] 孙继平,贾倪. 矿井电磁波能量安全性研究[J]. 中国矿业大学学报,2013,42(6):1002-1008. doi: 10.3969/j.issn.1000-1964.2013.06.018SUN Jiping,JIA Ni. Safety study of electromagnetic wave energy in coal mine[J]. Journal of China University of Mining & Technology,2013,42(6):1002-1008. doi: 10.3969/j.issn.1000-1964.2013.06.018 [12] 刘晓阳,马新彦,刘坤,等. 矿井5G电磁波辐射能量安全性研究[J]. 工矿自动化,2021,47(7):85-91. doi: 10.13272/j.issn.1671-251x.2020090050LIU Xiaoyang,MA Xinyan,LIU Kun,et al. Research on the safety of 5G electromagnetic wave radiation energy in coal mine[J]. Industry and Mine Automation,2021,47(7):85-91. doi: 10.13272/j.issn.1671-251x.2020090050 [13] MENG Jijian. Research on wireless power transmission in coal mine based on explosion-proof safety[C]. IEEE 4th Advanced Information Management, Communicates, Electronic and Automation Control Conference, Chongqing, 2021: 1700-1704. [14] 郑小磊,梁宏. 煤矿5G通信系统安全技术要求和检验方法[J]. 工矿自动化,2021,47(3):9-13,33. doi: 10.13272/j.issn.1671-251x.2021010066ZHENG Xiaolei,LIANG Hong. Safety technical requirements and inspection methods of coal mine 5G communication system[J]. Industry and Mine Automation,2021,47(3):9-13,33. doi: 10.13272/j.issn.1671-251x.2021010066 [15] 张勇. 煤矿井下无线射频近场谐振耦合防爆电磁能仿真分析[J]. 煤矿安全,2022,53(8):134-138. doi: 10.13347/j.cnki.mkaq.2022.08.021ZHANG Yong. Simulation analysis of explosion-proof electromagnetic energy coupled with radio frequency near field resonance in underground coal mine[J]. Safety in Coal Mines,2022,53(8):134-138. doi: 10.13347/j.cnki.mkaq.2022.08.021 -