Research On Protection Principle Against Wrong-phase Short Circuit Of The AC Traction Supply System

In accordance with the traction power supply and electric locomotives running for the grid operation requirements, electric locomotives must cut the power off when they pass the phase-splitter. When trains pass phase-splitter without cut their power off, an electric arc can be easily created. This electric arc will result in wrong-phases short cricuit, which is a serious close-in fault. Arc created in this processis very complicated and can be described by physical,chemical and electrical process.The arc is affected by dielectric medium,voltage and other factors so that the feeder protection can not react right. Arc is a strong power of sustained discharge phenomenon, the low voltage will maintain the stability of arc burning for a long while because A high temperature arc could break the wire, so this failure can cause terrible fault.This paper analyzes the formation of arc wrong-phase short circuit in the traction power supply system . Then gets the wrong-phase short circuit current in the traction substation and compare with protective settings. The system does not cut off power. So contact wire will be burn down by high-temperature electric arc. Our current protection settings is still not perfect, it is necessary to add new wrong-phase short circuit protection to the power supply system. As the arc is a complex factor(it will change when its environment, climate, temperature and many other factors'change). arc length is uncertainties, coupled with complex load traction power supply system, making it difficult to set accurate electrical parameters as wrong-phase short circuit occurs, the protection could act to cut off power, but also ensure normal operation of various electrical parameters although large changes in the scope of action but do not action. According to the rapid temperature rising of the electrical phase splitte contact wire in the case of wrong—phase short circuit arising. This paper puts forward a new strategy about relay protection for the wrong-phase short circuit, that is increasing the contact wire temperature protection setting . this paper proposed two different solutions, because they use different eqeipment to measure the temperature.