Analysis And Research Of The Magnetic Field And Loss For Traction Transformer

With the rapid development of electrified railways, its operation reliability isdirectly related to the safe operation of the power supply system. As a main equipment ofthe electrified railways traction power supply system, the reliability of traction transformeris directly related to the security of the entire power supply system. Traction transformerhas high leakage reactance and multiple winding. The characteristics of the traction loadare instability, it has much short circuit and high harmonic circuit. Its running environmentis more adverse than the general power transformer. So the ability of stronger overload andshort circuit impact resistance is requiremented for traction transformer. Those are also thecharacteristics of the traction transformer difference from general power transformer.Transformer’s tank is at a high leakage magnetic field, it is easy to cause losses andoverheating local concentration.For the problem of the transformer loss local concentration, this paper studies thespecial structure traction transformer magnetic flux leakage and the distribution of eddycurrent loss. This article analyzes the different kinds of traction transformer connectionmode and their advantages and disadvantages. The basic principle of negative sequencecurrent of the traction transformer will be researched.The type of leakage magnetic field and the effect of produce will be studied in depth.The main content is the eddy current loss of traction transformer. Taking a three-phaseV/V traction transformer as an example, this paper established a finite element analysismodel and circuit model. Circuit model is established according to60degrees wiring way,using field-circuit coupling analysis method, simulatied the transformer transient responseprocess. Finally,we can obtain voltage, flux linkage and current waveform, compared withthe theoretical analysis research.On the base of this research, this paper established the three-dimensional calculatiedmodel of the tank, analyzes the transformer magnetic flux leakage loss that brought by the magnetic flux leakage. Further, we can find the location that the loss is too large. In orderto reduce the eddy current loss of tank, considering add the magnetic shield to reduce theeddy current distribution of the tank. As a result, the eddy current loss has beensignificantly reduced. In addition, the influence of different thickness of magnetic shieldand the different installation position on the tank are researched, and this paper give somereasonable improvement measures. It is has important significance to optimization designof the special structure traction transformer.