Study On Traction Transformer Fault Diagnosis Technology Based On Dynamic Threshold

As one of the key equipment of traction power supply system, the performance of traction transformer operating state will directly affect the safety and stability of electrified railway system. However, the features of traction load make the different of gas information in oil between traction transformer and general power transformer. So the fault diagnosis technoligy which meet the operating characteristics of traction transformers should be studied specially, in order to achieve the purpose that assessment the running state of traction transformer accurately.Through simulation electric locomotives actual operation under different operating conditions, the characteristics of traction load are studied. Comparative the difference of the internal temperature and transformer insulation life loss between traction load and the equivalent load, the operating characteristics of traction transformers are researched. In addition, generation mechanism and dissolution mechanism of gas in transformer oil are analyzed, and the corresponding relationship between fault types and characteristics of the gas are introduced.Compare generation law of oil-paper insulation system under different low temperature, the actual acting impact ot traction load on the oil gas are studied. Through emulation transformer fault diagnosis process, the actual needs of traction transformer fault diagnosis are excavated, and dynamic threshold model of traction transformer oil gas are established on this basis.The basic knowledge of RBFNN are introduced and its structure are optimization designed accordingly. Furthermore, combined the dynamic threshold model of gas in oil and RBFNN a new fault diagnosis method of traction transformer is proposed. Results of the examples tests show that the diagnostic method correction by dynamic threshold can identify misjudgment fault case of the original method, it can further improve the accuracy of the original fault diagnosis method, which demonstrates the effectiveness of traction transformer oil gas dynamic threshold model and necessity, which demonstrates the effectiveness and necessity of dynamic threshold model of traction transformer gas in oil.