矿用电缆护套对电快速瞬变脉冲群感应耦合的影响

易燃、易爆危险环境中不能打开电气设备隔爆外壳进行直接测量,这就造成无法定量分析矿用电缆中电快速瞬变脉冲群的感应耦合骚扰限值。以双指数瞬态脉冲作为骚扰源,运用电路和电磁场理论建立矿用电缆的感应耦合模型,并进行数值分析。结果表明:矿用电缆金属护套可靠接地能够有效抑制电快速瞬变脉冲群的感应耦合骚扰,被金属护套完全包裹的电缆可以消除容性耦合骚扰。金属护套层越厚,感应耦合电压越小;电缆越长,感应耦合电压越高。缆皮终端接地电阻越小,感性耦合电压越低,屏蔽效果越好。电缆金属护套未接地时,会产生更高的感应耦合电压。巷道中与骚扰源同侧的电缆感应耦合电压比异侧的电缆感应耦合电压高。

Effects of Mine Cable Jacket on the Induction Coupling of Electrical Fast Transient Burst

Under the inflammable or explosive environment,the direct measurement methods by opening up the explosion-proof shell of electrical installations are not adoptable in mine.So,it’s impossible to have a quantitative analysis on the limit of the induction coupling disturbance of electrical fast transient burst(EFT/B) in such dangerous environment.Transient induction disturbance coupling model,which was EFT/B as it’s excitation source,was established based on circuit and electromagnetic theory.Furthermore,numerical analysis was performed.The results indicate that grounding cable metal jacket possessed the rejection capability for the induction coupling of EFT/B.Thicker cable metal jacket gave small voltage of induction coupling;small grounding resistance led to better screen effect.The capacitance coupling disturbance was avoided as the cable was enclosed by metal jacket completely,and inductance coupling voltage increased with the increase of cable length.The induction coupling voltage of un-grounding cable metal jacket was higher.Moreover,the cable coupling voltage on the same side of disturbance source was higher than that on the opposite side in tunnel.