Study On The Leakage Current Characteristics And State Detection Of Catenary Leakage

With the development of electrified railway in China, "four vertical and four horizontal" passenger line which has been put into operation. Most of electrified railway line running fault caused by defective insulations. The performance of insulator will be reduced when the surface contamination of catenary insulator is accumulated to a certain extent and in bad weather conditions (such as fog and drizzle). Insulator pollution flashover is very easy to create, which brings the serious loss for the railway operation. Insulator leakage current contains not only a wealth of feature information, but also have a close relationship with their surface contamination. Analysis the status information of catenary insulator through detection of its leakage current, establish an evaluation model that contamination condition of insulator, and judge the catenary insulator surface contamination. This reference has been provided for pollution flashover of insulator cleaning in actual operation.The test of leakage current contains a lot of noise signal because of severe cases and locomotive interference. Using the device of leakage current to test on-site experiment, and studied the interfering with catenary insulator leakage current when train passes. Identify the data when train passed is proposed in this paper. Used the "Fenestration" for preprocessing the signal, remove the interference data of catenary insulator leakage. Then, filter the leakage current signal after pretreatment based on wavelet threshold of EMD, wavelet threshold and EMD. And using the waveform characteristics, leakage current effective value the three harmonic and fundamental amplitude ratio analysis of the de-noising effect. Obtained that catenary insulator leakage current signal with wavelet threshold filtering method based on EMD de-noising effect is the best for insulator leakage current signal.Based on the data of the artificial pollution test, Analysis the time domain and frequency domain characteristics of porcelain insulator leakage current signal. On the one hand, analyzes the relationship between the leakage current effective value, maximum value and the insulator contamination degree. On the other hand, comparison of different odd harmonic and fundamental amplitude ratio between insulator contamination degree. Conclusion the three harmonic and fundamental amplitude ratio can reflect the pollution degree of porcelain insulator. And study on the relationship between the EEMD energy entropy of leakage current and the contamination degree insulator. Experiments show that the EEMD energy entropy can be used as an parameters for the model of insulator contamination condition assessment.The characteristics of leakage current (The effective value, maximum value, three harmonic and fundamental amplitude ratio, EEMD energy entropy) and humidity of the environment as the input parameters of insulator contamination condition assessment model. Established and verified the network insulator pollution status of exposure assessment model using the test data. The result shows that the model can effectively determine the surface pollution condition of catenary insulator.