Regenerators for traction substations

Metro is one of the most important means for ensuring population mobility in large cities. However, having a number of metro advantages: high mobility, environmental friendliness, maintaining city architecture, high security, there is a negative factor — high power consumption.

With passenger transportation volume rising and constant growing of tariffs for electric power, reduction of power consumption by this kind of transport becomes especially actual.

One of the measures to reduce power consumption in metro is the use of metro train braking kinetic power by installation of additional regenerators in traction substations.

up to 30% of power saving consumed by rolling stock

short payback period

modern control and protection system

materials and components of leading world manufacturers

Advantages

Application of regenerators allows to:

improve metro energy indicators by regeneration of energy released during train braking (having regenerative braking mode in electric rolling stock);
reduce overvoltage level occurring during regenerative braking;
facilitate metro ventilation modes (studies show that application of dynamic braking dissipating the braking energy as heat in resistors leads to a marked increase of power required for metro ventilation);
save up to 30% of power consumed by rolling stock, depending on the terrain.

CONVERTER SECTION
OPERATING PRINCIPLE
CONTROL AND PROTECTION SYSTEM

Converter sections (hereinafter CS), series I-PTE, produced by Pluton together with dry-type transformers, manufactured by RESIBLOC® technology are applied as regenerators for metro traction substations.

Regenerator CS is a thyristor six-valve bridge, rated current 800 A. 12-pulse inversion circuit is traditionally used, i.e. two sections of 800 A each, switched with a shift of 30 electrical degrees. Total current of two sections is 1600 A.

Such circuit has an advantage in comparison with traditional 6-pulse inversion circuit in terms of harmonic composition of inverted current and voltage.

Regenerator capacity can be expanded by connection of two additional sections to the existing two. It will provide rated current of 3200 A.

CS series I-PTE, were developed and manufactured using the most modern technologies, materials and components from leading world manufacturers. CS are based on power pill thyristors 2760 A, class 28, produced by Dynex. CS cooling is natural or forced air, depending on CS operating conditions.

Generally, existing substations cannot provide regeneration of braking energy due to unidirectionality of their rectifier units. After regenerator installation excess of energy arising during train braking automatically returns to network.

Any time braking energy can be given via regenerator to medium voltage network, transferred over long distances and used by different consumers both auxiliaries (escalators, lighting, ventilation) and outside consumers.

Advantages of thyristor regenerators:

relative simplicity of the circuit;
good resistance to overloads and short circuits;
high efficiency;
availability of components;
relatively low price.

Control system is based on microprocessor module developed by PLUTON. This module fulfills control, diagnostic and protection functions of regenerator.