Research On Insulation Fault Of Traction Transformer And Online Monitoring Technology

With the increase of investment of the state on railway construction, china railway is facing an age of fast development. High-speed and heavy freight railway are becoming a significant strategic direction of railway. In order to ensure the smooth operation of high-speed and heavy railway, it is necessary to put forward higher requirement on the reliability and security of traction power supply system. Traction transformer as a key component of traction power supply system undertakes the major role of transforming voltage. Monitoring the working status of traction transformer to reduce the probability of traction transformer failure is one important way of improving the electric railway transportation efficiency and reducing maintenance cost.In the past, the regular preventive insulation test was always used to detect the electrical equipment insulation, which plays a certain role on reducing electrical insulation failure but exists many drawbacks at the same time. In the testing, the insulation status could not be completely reflected insulation damage that may be caused by testing resulting in the accident, and the sudden failures could not be predicted and prevented, which not only reduces the efficient detection but also raises the additional human and material cost.The insulation state parameters of electrical equipment could be got by condition monitoring technology for continuous effective monitoring to electrical equipment, without affecting the operation of them, which optimizes the running of electrical equipment. The condition monitoring technology used in the traction transformer can reduce the outage time and improve the quality of fault detection and diagnosis efficiency. Currently, the condition monitoring technology is more mature and also more widely used in power transformer, but less in traction power supply system. Meanwhile the way is relatively simple. The research should be further studied to extend traction transformer condition monitoring technology.The insulation mechanism and reason of the traction transformer are analyzed in this paper. On the base of studying the monitoring object and technology of the current transformer online monitoring system, the whole structure and mode of operation of traction transformer online monitoring system are proposed. The zero-flux current sensor is used as the hardware means to access micro-current signals through the analysis of existing technology. The system works well in the field. The researches on self-protection of the condition monitoring system, on-site signal interference and shielding protection are analyzed at the same time in this paper.