Study On On-Line Monitor Based On DGA For Insulation Of Traction Transformers

Traction transformer is a critical element of a traction power supply system. Its reliable and continued performance is key to safe and profitable of electric railway power system. The traditional off-line gas chromatogram method is mainly applied to judge the running status of the running traction transformer. But it can't trail the development of the faulty, and it has many other shortcomings such as complexity of processing. So it is an urgent problem that how to development a traction transformer on-line monitor, which can find out inner faulty to Guarantee the traction transformer safe and high-efficient operating, as well as improve the operation efficiency of the electric railway.Combined with the strongpoint of the dissolved gas analysis (DGA) and the on-line monitoring method, the DGA on-line monitoring system for electric power industry is developed able to monitor the dissolved gas in the oil and analyze it without stopping the devices. After analyzing the characteristic of the traction load and the transformer faulty, the DGA on-line monitoring system for traction transformer based on DGA technology is developed to realize the online monitor to the traction transformer oil dissolved gas H₂ CO CH₄ C₂H₆, C₂H C₂H₂.According to the requirement of the "Guide to the analysis and the diagnosis of gases dissolved in transformer oil", Duval's triangle approach and fuzzy three ratio analytic approach are introduced to overcome the inherent defect of tradition three ratio approach. The diagnosis method that combines the fuzzy algorithm with neural network algorithm is further discussed and practiced.In this thesis, the design ideas and the realization of the on-line monitor are introduced in detail, including the whole structure, the principles of main modules, and the design of the hardware and software.