Study Of Single Transform In Co Phase AT Power Supply System

At present, our country is in the high-speed railway construction upsurge. And high-speed, overloading railway technology is the most important development direction. However, there is much problem in present power supply system, such as harmonics, reactive power, and communications disturbance not only reducing the efficiency and quality of power supply, but also being a threat to reliable operation .So, building a novel traction power supply system is the fundamental solution to ensuring its safety and reliable operation.First, the paper discusses the common problems in current traction power supply system and the general solutions to these. It also presents three modes of power supply and their characteristics.Secondly, the paper briefly discusses the principle of co phase power supply system and the ways of how to realize it including two major methods: one is reactive symmetry compensation technology, and the other is based on the balance of active filter transformer.Then, this paper proposed four types based on the YN,d11 connection transformers. Also, the structural characteristics are studied. As the single transformers has simple connections, lower investment, and easy operation or maintenance, this paper has focus on them (single transformer-55 and single transformer -27.5) which only need a transformer (double-winding) and a balance transform devices.Focused on single transformers, the paper studied their banlance transforms, power converter, alsoanalyzed for its harmonic and reactive real-time detection technology, balance transformer and active power filter control technology. At last, the paper built single transformer simulation mode by Matilab / Smulink. Compared with single transformer-55 ,the other one single transformer -27.5 is more favorable.