Low-frequency traction power supply system

Abstract

The invention discloses a low-frequency traction power supply system which is composed of traction substations and traction networks. Each traction substation comprises a traction transformer and a transducer, a primary-side three phase of each traction transformer is connected with a public utility grid, a secondary-side three phase of each traction transformer is connected with the corresponding transducer, traction sides output by the transducers is single-phase, and the traction networks are powered through single-phase traction buss. The power supply frequency f of the traction networks meets the following formula: fault removal time limit TS (ms) of the traction network=relay protection action time TR (ms)+half cycle lambda (ms), namely, f=500/(TS-TR), TS)TR and within 5Hz-16Hz, the traction networks of the traction substations can be connected to implement communicated power supply, and during interruption maintenance or traction-side fault of the traction substation, the transducers are switched off and related breakers are switched on. The low-frequency traction power supply system is widely suitable for power supply of metros with one line at one place, light-rail vehicles, tramcars and trolleybuses with two electric traction lines, and convenient to implement.

Description

technical field [0001] The invention relates to the field of transportation, in particular to a low-frequency traction power supply technology. Background technique [0002] Taking advantage of the single-phase traction power supply system's advantages of simple structure, low construction cost, and convenient operation and maintenance, the main line electrified railway generally adopts a relatively high voltage (27.5kV) single-phase power frequency AC system, while urban subways, light rails and railways Public transportation such as rails and trolleybuses generally adopt a lower voltage direct current system. [0003] The electrified railway adopting the single-phase power frequency alternating current system directly draws power from the public grid, only uses low-cost and reliable transformers, does not use high-cost converters, and has the remarkable characteristics of large traction power and large transportation volume. However, there will also be negative sequence-ba...

AI Technical Summary

Problems solved by technology

At the same time, since the volume of the transformer is inversely proportional to the frequency, low-frequency power supply will increase the volume of the transformer and become extremely uneconomical. Therefore, it should be avoided to use transformers in low-frequency traction power supply systems. In other words, converters are widely used in public transportation vehicles Today, with the AC drive technology of the main circuit, the voltage of the low-frequency traction power supply system that directly supplies power to the vehicle will not be too high due to factors such as the withstand voltage level and economic performance of the converter (frequency converter), generally up to several thousand volts , but with the growth of traffic capacity demand and the development of converter technology and manufacturing technology, higher voltage may be used in the future to further increase power supply capacity

Images