Researches On The Electromagnetic Effect From High-speed Railway's Traction Power System To Signal Cable

This paper researched on the electromagnetic effect from traction power system to signal cable on high-speed railway. Series useful disciplines and conclusions were founded, and some necessary protection measures were pointed out. The main works were listed as the follows:First, the new characteristics of electromagnetic effect from high-speed railway's traction power system to signal cable were analyzed. Although AT power supply and earthing through system were used on high-speed railway,which could effectively induced electromagnetic interference to signal cable,but other factors could increase the electromagnetic interference to signal cable, such as high current of traction power system, close distance between signal cable and run-through ground wire, viaduct, unballasted track and whole track bed. So it's important to make research on this project.Then, the MTL model of high-speed railway's traction power system was founded according to MTL (multi-transmission line) theory. The two line's lumped parameter model was derived and extended to the case of multi-conductor transmission line. The MTL equation was found by"F"lumped parameter form and node voltage method. The equivalent modeling of series-connection component and parallel-connection component was made, based on the MTL's equivalent chain network theory. Plenty care on equipment's data and related parameters were taken, and complicated node connection relation was surveyed, in order to adapt to the actual situation of high-speed railway.Next, the interference from traction power system to signal cable was calculated under both normal and fault conductions:First, a typical section of traction power system was modeling and the current and voltage of run-through ground wire were calculated, according to which the longitudinal induced electromotive force of signal cable's core line were calculated.Second, concrete analysis of electromagnetic effect from run-through ground wire to signal cable was made: distributary's theory was created and calculation formula of mutual induction coefficient was derived out, the longitudinal induced electromotive force of 2km length and 15km length signal cable was calculated and compared. At the same time, field test was done, the result was close to calculated value.Third, in terms of engineering application, the comparing calculation was made to analyse the difference of double-grounding mode and single-grounding mode. Result turned out that the double mode was inferior to single mode from the point of reducing the longitudinal induced electromotive force of signal cable's core line.The measurement dada validated the correctness of the calculated result.In order to get more discipline of electromagnetic protrction on high-speed railway, variation of related peremeters was analysed: the train's position, the leaking impedance of AT, the diatance between nabourhood AT, the leaking impedance of rail.At last.At last ,the technical mearsures that could induce the traction power system's electromagnetic effect on signal cable were proposed.The main creative issues of this paper were:The run-through ground wire was added into the MTL model of traction power system.The potencial and current of run-through ground wire along the railway was calculated, by the measurement data, calculated curve simulated the real circumstance effectively.In terms of reducing the longitudinal induced electromotive force on signal cable's core line, the comparing calculation was made to analyse the difference of double-grounding mode and single-grounding mode.