The Influence Of Railway Strong Electromagnetic Interference On The Signal System

With the rapid development of electrified railway, more and more electronic products are used in modern electrical railway signal system. The coexistence of electronic products and railway electric equipment makes the electromagnetic environment become more complex. Signal system is a weak current system and in a subordinate position in electrical railway system. And the signal system are sensitive to electromagnetic interference (EMI) and fragile to over voltage, which will affect the security and reliability of the devices. So, making research on the electromagnetic interference on railway signal system has an important theoretical significance to railway signaling protection.This thesis makes research on two important kinds of rail way signal system EMIs and analyses the railway traction power supply system and the electromagnetic interference of arc in the pantograph-catenary systems of electromagnetic radiation on the signal system..It mainly contains electromagnetic interference of traction power supply system、interference of ground potential rise and interference of arc in the pantograph-catenary systems.Electromagnetic interference of the traction power supply system mainly is traction return impact on signal cable. First, concrete analysis of electromagnetic effect from run-through ground wire and cable sheath to signal cable core was made:calculation formula of mutual induction coefficient was derived out, the longitudinal induced electromotive force of2km length and15km length signal cable was calculated. Second, the comparing calculation was made to analyze the difference between double-grounding mode and single-grounding mode and presented some advices. Then, the ground potential rise caused by run-through ground wire was analyzed.The main source of electromagnetic interference noise in the electric railway is the high frequency oscillation pulse caused by electric arcs when the detachments happened between the pantograph-catenary systems. This thesis researched the electromagnetic interference characteristics based on high frequency electromagnetic simulation software FEKO. This thesis draws a conclusion about a series of distribution of the electromagnetic radiation characteristics of arc through the simulation results. In simulation results and previous relative reference and the experiment test comparison the conclusion are proved to be correct in the simulation models.