矿用电缆工频电磁波能量辐射特性研究

Research on characteristic of power frequency electromagnetic wave energy radiation of mine-used cable

矿用电缆的工频电磁干扰是影响井下无线通信可靠性的重要因素之一。由于工频电磁波波长远大于矿井巷道尺寸,工频电磁波在矿井巷道中无法进行有效的电磁场能量转换,不能采用自由空间电磁波电磁耦合传播方程来研究矿用电缆工频电磁波能量辐射特性。针对该问题,建立了基于短偶极子的矿用电缆工频电磁波能量辐射模型,推导了短偶极子的磁场和电场表达式;采用有限元法和有限差分法,通过数值计算分析了矿井巷道不同位置的矿用电缆辐射电场强度。结果表明:与电缆在同一高度的各点电场强度随着各点与电缆间距离增大而逐渐减小;与电缆在不同高度且与巷顶平行的各点电场强度随着各点与电缆间距离增大而逐渐减小,且电场强度比与电缆在同一高度的对应位置各点电场强度小;与电缆同侧的各点电场强度随着各点与电缆间距离增大而逐渐减小;与电缆不同侧的各点电场强度小于与电缆同侧的各点电场强度,且受各点与电缆间距离的影响较小。

Power frequency electromagnetic interference of mine-used cable is an important factor which affects reliability of underground wireless communication.Wavelength of power frequency electromagnetic wave is much larger than mine roadway size,so electromagnetic field energy conversion of power frequency electromagnetic wave cannot be executed effectively in mine roadway,and electromagnetic coupling propagation equation of electromagnetic wave in free space cannot be used to study characteristic of power frequency electromagnetic wave energy radiation of mine-used cable.In view of the problem,a model of power frequency electromagnetic wave energy radiation of mine-used cable was built based on short dipole and formulas of magnetic field and electric field of the short dipole were deduced.Based on finite element method and finite difference method,electric field intensity of mine-used cable at different location of mine roadway was analyzed though numerical calculation.The results show that electric field intensity ofvarious points at the same height as cable decreases with increase of distance between each point and the cable.Electric field intensity of various points at height differing from cable and parallel to roadway roof decreases with increase of distance between each point and the cable,which is smaller than the one at the same height as cable.Electric field intensity of various points at the same side as cable decreases with increase of distance between each point and the cable.Electric field intensity of various points at side differing from cable is smaller than the one at the same side as cable,which is less affected by distance between each point and the cable.