Research On Damage Protection For Insulation Joints Of ZPW-2000 Station Track Circuit

The insulation joint is major equipment of station track circuit,which plays an important role in isolating the track circuit information of the adjacent section.When the insulation joint is damaged,the track circuit carrier frequency information of the adjacent section will interfere with each other,the on-board equipment will receive the error code and so on,which bring uncertainty to the safe operation of the train.In order to solve the problem that the carrier frequency information of the adjacent section will interfere with each other when the insulation joint is damaged in the station of the high speed railway,according to the structure of the traditional choke transformer,this thesis puts forward a kind of protection scheme that using the protection choke transformer to eliminate the carrier interference frequency of the adjacent section.The main contents are as follows.Firstly,according to the structure of the traditional choke transformer and the related anti-interference requirements,the traditional choke transformer is improved.For example,the anti-interference level of the choke transformer was improved by increasing the iron core air gap thickness of the traditional choke transformer.And for the sake of reducing the interference energy,the 50Hz series resonant circuit is paralleled on the traditional choke transformer secondary side.At the same time,paralleling a capacitor C₂ on the traditional choke transformer secondary side is needed to assure the reliable transmittal of the frequency shift signal.Through the above improvements,an improved choke adapter transformer suitable for the ZPW-2000 station track circuit is obtained.Secondly,the different model characteristics of the choke transformer are analyzed,and the model of improved choke adaptor transformer is established by the parallel equivalent circuit model,which embodies the equivalent excitation inductance of the secondary side.According to the established model and the relevant anti-interference requirement,the relevant parameters of the improved choke adaptor transformer are obtained,and the anti-interference ability is analyzed.The results show that the improved choke adaptor transformer has better anti-interference performance.Then,analyzing the insulation joint damage condition of the ZPW-2000 station track circuit,the insulation joint damage protection circuit is paralleled on the secondary side of the improved choke adaptor transformer,and the interference frequency of the adjacent section can be eliminated by the series resonant circuit part of the insulation joint damage protection circuit.And through the parallel resonant circuit part of the insulation joint damage protection circuit to ensure the frequency shift signal can be transmitted reliably under normal conditions.According to the above protection scheme,a kind of protection choke transformer with insulation joint damage protection circuit is proposed,and its related parameters are obtained,and its anti-interference performance is analyzed.Finally,the four terminal network model of the improved choke adaptor transformer and the protection choke transformer are established,and the four terminal network parameters under different carrier frequency are simulated and calculated.It provides the basis for the establishment and the calculation of the track circuit complete model in the high speed condition,which is beneficial to analyze the transmission characteristics of the track circuit.