Research On Galloping Online Monitoring And Condition Assessment For Catenary Positive Feeder Of Lanzhou-Urumqi High-speed Railway In Gale Area

Since the opening of Lanzhou-Urumqi high-speed railway,the galloping of catenary positive feeders occurred many times in the gale area,which caused the fatigue of suspension points,broken strands and power failure of traction power supply.In the traditional mode,the monitoring of catenary depends on manual inspection,and the work efficiency is too low.Therefore,the research on the online monitoring technology of catenary positive feeder galloping and the theory of conductor state condition assessment in the gale area of Lanzhou-Urumqi high-speed railway is of great significance for ensuring the operation safety of Lanzhou-Urumqi high-speed railway and other gale wind areas and improving the level of railway intelligent management.Firstly,based on the analysis of the actual situation of Lanzhou-Urumqi high-speed railway,this thesis proposes a multi-point online monitoring method of catenary forward feeder galloping based on distributed heterogeneous wireless sensor network,and analyzes the monitoring nodes,installation mode,measuring points layout,power supply and other components of the monitoring system.It is designed to improve the adaptability of the monitoring system to the railway site.The three-axis acceleration sensors are used to synchronously collect the galloping information of each monitoring point,and the Zig Bee wireless communication network is constructed to transmit the monitoring data.The communication quality and monitoring accuracy of the system are tested on the built simulation test platform of wire galloping monitoring,which verifies that the designed monitoring system meets the basic requirements of online galloping monitoring,and can accurately reflect the wire galloping condition.Secondly,to solve the problem that the integration result is seriously distorted due to the existence of trend term in the integration process of online monitoring acceleration data of galloping,a wire galloping localisation algorithm is proposed to correct the waveform of galloping signal.Based on the detailed analysis of EEMD(Ensemble Empirical Mode Decomposition)anti-mode aliasing principle,the integral signal is decomposed into 10 IMF(Intrinsic Mode Function).According to the characteristics of approximate symmetry about time axis of galloping signal,an improved method of recognizing and reconstructing trend term is proposed,which realizes the extraction and elimination of trend term in signal.Compared with the moving average method,the feasibility and effectiveness of this thesis are verified.In addition,the selection of the parameters of the galloping localisation algorithm is further discussed,and the range of values suitable for the galloping signal processing is given.Finally,to research the mechanical characteristics of the positive feeder under galloping state and evaluate its fatigue state,the tension on the conductor is calculated based on the monitoring parameters such as the amplitude,frequency and half wave number of galloping,and the change of tension with galloping time is determined.According to the structural and material characteristics of the positive feeder,the finite element 3D model of the positive feeder is constructed by the ABAQUS software.The correctness of the model is verified by the comparison between the theoretical calculation and simulation results of tension stratification,and the mechanical changes of the whole and section of steel strand and aluminum strand in the positive feeder under different tensile loads are mainly analyzed.According to the cumulative damage theory,combined with the meteorological information of railway field,a method for estimating the galloping fatigue life of conductor is introduced,and the specific assessment process and steps are given.