Study On On-Line Monitoring System For Main Transformer Of Electric Locomotive

Main transformer of electric locomotive is an important assembly on electric locomotive, whose reliability and durative is the guarantee to the safety of locomotive's running. Main transformer always runs in a relatively bad condition. According to the main transformer running instances for many years, although its fault ratio is not high, it will bring considerable loss when its fault happens.The traditional out-line diagnosis methods and shutting down locomotive in the affairs station for detection can not find out potential fault effectively in its running condition, only providing lagging information of main transformer's fault or its accident, and hardly adaptting to the development current of locomotive state repair nowadays. This paper develops researches based on the project of locomotive running state monitoring, completes the design of the main transformer's on-line monitoring assembly, primarily realizes the state repair of locomotive's main transformer.It studies the transformer structures, causes of kinds of transformer's faults and their diagnosis methods. Also it designs the on-line monitoring assembly of the locomotive main transformer that takes gas dissolved in oil and the oil temperature as state variables. The assembly adopts macromolecule velum oil-gas segregator, applies semiconductor gas-sensitive sensor to examine state signal of diagnostic gas, uses digital temperature sensor DS18B20 to examine temperature signal. The assembly adopts the centralized-dispersed data-collection processing mode, which sends all the data to the upper machine by the CAN bus for storage and transmitting. The Intelligent fault diagnosis system on the ground achieves the function that displays and analyses the data, diagnoses the fault, and so on.It completes the rational design of the whole scheme, illuminates the selection of main equipments' type. Also it achieves the software and hardware design of signal modulation circuit, communication module circuit, etc. In order to analyze, estimate and foretell the fault of main transformer, confirm its character, type and extent, this paper applies ANN and fuzzy mathematics method to diagnose the fault of main transformer, uses expert system to achieve combination between the conclusion of ANN and fuzzy mathematics based on D-S Evidence Theory by the reasoning mechanism of information fusion technique.In the end of this paper, it uses the data of main transformer faults collected by the assembly to validate and analyze the diagnosis system. The result indicates this diagnosis system can reduce the error of fault diagnosis and enhance the reliability of fault diagnosis.