Condition Assessment Of High-speed Railway Catenary Based On Detected Parameters

The catenary system plays a very important role in railway operation.When a catenary failure occurs in a high-speed line,it will stop the operating trains and cause heavy losses of economy and property.To facilitate the operation and management department to investigate the operational condition of catenary and provide references for the condition-based maintenance of catenary,this paper studies the condition assessment methods of catenary using data such as pantograph-catenary contact force.The overall condition and local condition of catenary will be assessed.First,based on the simulation data of pantograph-catenary interaction,the extraction method for the non-catenary structure wavelength(non-CSW)is studied.Complete ensemble empirical mode decomposition(CEEMD)is used to decompose the contact force simulation data to obtain several intrinsic mode functions(IMFs)and a residual.Then,the power spectrums of all IMFs are obtained and analyzed using the autoregression(AR)model spectral estimation.Finally,the IMFs and residual whose abscissas values of the corresponding power spectrum extrema are not in the range of dropper spacing and span are reconstructed to obtain the non-CSWs.By analyzing the power spectrums of the non-CSWs of contact force under the influence of global irregularities of contact wire,it is found that the extracted non-CSWs effectively preserve and highlight the irregularity information of catenary.Second,the effectiveness of using power spectrum exponential entropy(PSEE)and power spectrum shannon entropy(PSSE)of the non-CSWs as the overall condition indicators of catenary is studied and compared with other condition indicators.The results show that the PSEE and PSSE of non-CSWs calculated from the simulation data of pantograph-catenary contact force and conductor height increase with deterioration of catenary condition,which can more clearly and accurately reflect the change of catenary condition.Third,an overall condition assessment method of catenary is proposed based on power spectrum entropy.The PSEE of non-CSWs is calculated from the measurement data of pantograph-catenary.Then,the PSEE is used as condition indicator for the overall condition assessment of catenary.By comparing and analyzing the condition assessment results and the maintenance records of catenary,it is shown that PSEE can effectively characterize and evaluate the overall catenary condition,which provides a new method for catenary condition assessment.Finally,a method for assessing the local condition of catenary based on set-pair analysis and evidence theory is proposed.Based on the local condition assessment index system of catenary,the coefficient of variation and the analytic hierarchy process are combined to determine the weight of each assessment index,and the corresponding variable weights are obtained according to their relative impairment grades.Then,the connection degrees between each assessment index and each condition grade are determined by set-pair analysis,which are used as basic probability assignments.The revised basic probability assignments are then fused by evidence theory to get assessment results.At last,the condition level of catenary is determined by the maximum membership degree law and confidence criterion.The results show that the method proposed in this thesis can effectively identify the local condition of catenary and the differences between condition levels are more distinct compared with the fuzzy comprehensive assessment method.The method provides a new way for catenary condition assessment.