Ananlsis And Research On Power Supply Capacity Of High-speed Railway Traction Transformer

With the rapid development of the railway, the reguirements of the power supply ability is higher and higher. The traction transformer, is the core part of the traction power supply system, whose main function is to buck, split phase and supply power for the traction load, so the load capacity of traction transformer is the key index of the traction power supply ability, even relates to the whole railway transportation capacity. The electricity of traction network is provided by traction substation. The power supply arm of the adjacent substation is insulated from each other. Once the external power loses the voltage, or when the traction substation equipment has faults and causes power outages, the adjacent substation supplies power to the traction substation that has a power failure, which is called the area of power supply. The area of power supply causes the extended power distance of the traction substation, increases the train operation density of power supply arm and affects the power supply capacity of traction transformer. In order to ensure the safe operation of the failure of the traction power supply system, when designing the traction transformer, its capacity usually was left a large margin. But for the lines that the train density is small and the load rate is low, it will lead to larger traction electricity expenses and serious resource waste. Therefore, it is necessary to carry on economic and technical analysis and research for traction power supply ability, provide evidence for making full use of the utilization of traction transformer power supply.This paper adopts the research method of combining numerical simulation, theoretical analysis, and sence measured data. The simulation model of the traction network, traction transformer and electric locomotive were built. This paper uses the theory of Carson to simplify the order reduction traction of multi conductor transmission line, builds equivalent circuit based on lumped parameter model, analysizes the distribution of electric current of the whole parallel AT power supply mode and obtains the formula for calculating current. For our country’s commonly used pure single-phase, YND11, Scott, VV and VX traction transformer connection types, this paper has carried on the theoretical analysis and simulation, verified the applicability of the simulation model and built the CRH3 type electric locomotive simulation model. Caculating the supply capacity of traction power supply system for the normal power supply and the area of power supply, it is concluded that the biggest number of the train under the condition of the traction transformer capacity. And this paper built shared coupling equivalent model in the EMTP-ATP simulation platform. This paper calculates temperature rise and life loss of the traction transformer and analysis traction load effects on traction transformer under the condition of the normal power supply and the area of power supply. On this basis, this paper carries out the economic analysis of the traction power supply system and puts forward a kind of load analysis algorithm based on threshold theory. Under the current two-part electricity pricing mode, this paper chooses the suitable way of calculating electricity price according to the traction transformer load rate afte traction load analysis and calculation and provide a basis for the realization of the traction transformer economical operation. The analysis and contrast with a large amount of measured data show that, the research match with spot data and have certain directive meaning to production.