煤矿井下无线电波防爆安全功率阈值研究

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.

     

/

返回文章
返回