Research Of Feeder Protection Of High-speed Railway Traction Power Supply System

As the implementation of China's "Medium and Long-term Railway Network Planning", especially under the background of global financial crisis, the government has added external 2 trillion RMB for railway construction, so that the railway construction encountering a new peak in which the high-speed railway becomes the focus of the construction. The high-speed railway cannot run safely without protection of traction power supply system. This paper has studied the feeder protection of high-speed railway traction power supply system.This paper firstly introduced the component of electrified railway traction power supply system from different sides such as the transformers' connection mode of traction substation, the supply mode of traction power supply system and the supply mode of traction network. By comparing the characteristics of all kinds of supply mode, promoted a traction power supply mode which suitable for high speed electrified railway. That means the transformers' connection mode of traction substation applied V/V connection which consist of two single-phase transformers, and the downstream and upstream lines were paralleled in the AT station and section post which formed the full parallel AT supply mode. Based on all of these, established a supply arm of the traction power supply system as the research model, and analyzed the calculation of impendence which under the full parallel AT supply mode.Integrated traction line fault in all its forms, there are short-circuit fault, the complex grounding fault with interruption and fault-phase short circuit fault. This paper made current analysis for the feeder short circuit fault, the complex grounding fault with interruption and fault-phase short circuit fault, and then figured out the protection configuration of the traction power supply system correspond with these faults. According to the operation statistics, short circuit fault is the majority, and the distance protection is the most effective protection mode to avoid it. As the relationship between impendence of full parallel AT traction network and distance is nonlinear, the feeder of traction network should not only choose the distance protection as the main protection, but also use the current quick breaking protection, the current increment protection and over current protection as the back-up protection.Because of its special advantage, the distance protection is always the main protection in China's electrified railway feeder protection. Considering some of its defects, This paper put forward the idea to apply ANN (Artificial Neural Network) into distance protection and build the distance protection model based on ANN.Finally, this paper reports the simulative result of this new model of ANN. Numerous samples firstly acquired from simulating a high-speed-railway traction power supply system with ATP, and trained the ANN model established by the Matlab neural network toolboxes. According to these samples, the reliability of ANN model is verified. The satisfactory result simulation shows that the adaptive distance protection based on ANN is promising and the research developing value of application will also make greater progress in the future. The scheme will be brought to center stage and make greater progress in the coming years.