On-Line Monitoring of Early Insulating Faults in Traction Transformer

Early insulating faults are not easy to be discovered through preventive off-line tests for the insulating status of a traction transformer, but can be accurately represented by the change of the trace gases dissolved in insulating oil. In order to give a real-time report about the status of the dissolved trace gases in insulating oil, and timely diagnose the early insulating faults, on-line monitoring must be performed. There exist several key problems in taking this technical measure, such as accurately extracting the information of the trace gases dissolved in insulating oil, solvingthe interference problem in information transmission, and developing and applying the hardware and diagnostic software for information processing. In this paper, the authors use a filter sensor to collect the information to be detected, employ digital transmission and anti-interference codes to eliminate electromagnetic influences, and utilize a hardware de- vice with 8098 monolithic computer and an expert diagnostic systemwhich is based on“the in- troductory rule of analysis and judgement for dissolved gases in transformer oil (GB 7252-87)” to realize the on-line monitoring and controlling of early insulating faults in traction transform- er.