Direct-current power distribution scheme design method for rail transit long-distance electric equipment

Abstract

The invention provides a direct-current power distribution scheme design method for rail transit long-distance electric equipment, and the power distribution scheme adopts a flexible direct-current power distribution system which mainly comprises a rectifier, a direct-current cable and an inverter. The design method comprises the following steps: determining the rated voltage Un, the rated power Pn and the power supply distance l of electric equipment, and calculating the power sum Pe of all the electric equipment in the power distribution line in the peak period of power utilization; determining a line design scheme by comprehensively considering the requirements of the load grade and the load characteristic; determining the capacity of a rectifier and the capacity of an inverter according to the power sum Pe in the power utilization peak period; preliminarily selecting a direct-current cable sectional area according to a cable current-carrying capacity and voltage drop formula; and establishing a direct-current power distribution system mathematical model, verifying line voltage loss, terminal voltage of electric equipment, line no-load voltage and starting current conditions in the normal starting and running process of the equipment, and determining the size of a cable section. The flexible direct-current power distribution system is adopted as a power distribution scheme of rail transit long-distance electric equipment, and compared with a conventional alternating-current power distribution scheme, line loss is small, voltage quality is greatly improved, power supply reliability is high, and cable manufacturing cost is saved.

Description

technical field [0001] The invention is applied to the technical field of rail transit long-distance low-voltage power distribution, and specifically relates to a DC power distribution scheme and a design method for rail transit long-distance electric equipment. Background technique [0002] With the introduction of the concept of urban agglomeration, cities rely on the developed transportation infrastructure network to connect more closely, and the development of cities gradually extends from the core area to the surrounding areas, and the distance between rail transit intervals increases accordingly. Interval water pumps, fans and other electrical equipment as primary loads have a long power supply distance, and the conventional AC power distribution scheme is difficult to meet the voltage quality requirements during operation. When the cable cross-section is constant, the impedance of the cable increases with the increase of the cable length, and the voltage drop caused b...

AI Technical Summary

Problems solved by technology

However, as the cable cross-section increases to a certain extent, the effect of reducing line impedance is less obvious, so the effect on reducing voltage loss is also very limited.

[0005] Therefore, it is difficult to meet the operating voltage requirements of long-distance and heavy-load electrical equipment by adopting the AC power distribution scheme in the prior art

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