The AC27.5 KV Traction Power Supply System Design Scheme Of The Engine Vehicle

Since the electrified railway power supply system in China is unified as a single-phase 27.5 kV voltage,all domestic trains operating on the main line are powered by 27.5 kV current.Therefore,this kind of special voltage system exists in locomotive and rolling stock manufacturing enterprises.However,different from the main line of railway operation,there is no so-called uplink-downlink relationship in the locomotive and rolling stock factory.Therefore,there is only one-phase power supply in the factory,so there will be unbalanced three-phase phenomenon on the primary side of the transformer.The existing locomotive and rolling stock plant is increasingly demanding the single-phase 27.5kV traction power supply,and it is necessary and worthwhile to continue to solve the AC27.5kV imbalance problem.The main contradiction of the AC27.5kV voltage in the locomotive and rolling stock plant is that the plant wants to make the traction load large enough,but it does not want to affect the stability of the 1OkV power grid on the incoming side because the traction load is too large.Therefore,how to solve this problem has become the focus of our traction power supply system design for locomotives and vehicles.In order to better provide owners with high-quality AC27.5kV traction power supply design plans in future design work,in-depth studies are conducted here.This paper will focus on four major parts,namely:the negative sequence characteristics of different types of transformers and the impact on the power grid,the design of the main transformer in the form of phase-shifted impedance matching balanced transformers,the design of the AC27.5kV traction power supply system,and AC27.5kV traction power supply Integrated automation protection settings.Through these parts,we will explain in detail why main transformers in the form of phase-shifted impedance matching balance transformers are widely used in locomotive and rolling stock plants,and how each system is designed.Among them,the traction transformer and the compensation device are mainly described.Since the different traction transformers and compensation devices can directly lead to the three-phase unbalance degree of the entire system and the power quality,it is a particularly important link.This paper compares and analyzes four commonly used domestic transformer balance compensation methods,and analyzes the characteristics of each method to determine which method is more reasonable in different situations.At the end of the article,we must pay attention to the aspects and final conclusions of today's locomotive and rolling stock plant in the future construction of AV27.5kV system.Through the analysis and comparison of experimental data,the effects of various system configurations and various compensation methods on the traction substation system in the railway factory were studied in the design scheme of AC27.5kV traction power supply system.