Study On The Influence Of Pantograph Arcing On Vehicle Transformer

The engineering practice indicates that the interaction between pantograph and overhead contact line has become the shackles that confine the development of the high-speed electrical railway, while the pantograph arcing is one of the key problems in overhead contact system (OCS). The pantograph arcing is the arc that generated by the breakdown of the air gap between the pantograph and the cantanary under strong electric field at the moment when the pantograph strip contact with or separate from the overhead line. It will cause overvoltage when the pantograph strip contact with or separate from overhead line and the overvoltage will be a great threat to the on-board electrical equipment’s insulation. The arc voltage and current waveform contain abundant DC component and higher harmonics. Once the DC component flow into the traction transformer, it will lead to exciting current waveform distortion and core saturation, which pose a threat to the locomotive’s safe operation. Thus, it has a great theoretic importance and application value to research the harmonic properties of the pantograph arcing and its effects on the traction transformer.In this paper, the generating mechanism of the patograph arcing was presented, based on the operating properties of the electrical railway and the gas discharge theory. The Pantograph-Catenary Arcing Experiment System (PCAES) was developed to carry out the dynamic characteristic test of the pantograph arcing. The relationship between the Pantograph-Catenary harmonic property and the locomotive’s traction current and the travelling speed as well as the influence of the load characteristics on the Pantograph-Catenary Arcing energy and the influencing factors of the contact-loss over-voltage were reasearched and analyzed.The model of the pantograph arcing and the main vehicle electrical equipment was established, and also the simplified traction power supply system model has been built to calculate the over-voltage level under different contact-loss modes which can be divided into three types according to the contact-loss duration. The transformer’s DC bias and excitation inrush current simulation model was made to analyze the influencing factors of the inrush current and the excitation inrush current under different DC component.The restrain measures aiming at the contact-loss over-voltage, DC bias and the excitation inrush were proposed, and the restraining effect was studied and verified as well.