The third-generation interlocking system used by RFI

ASDE3 by ECM is the third-generation interlocking system used by RFI for the protection and management of high speed circuit breakers at 3000 VDC, present in the electricity distribution plants supplying the rail traction lines.

Typically, the contact line for railway traction is divided into electrically separate sections of approximately 15-20 km, powered at the ends through high speed circuit breakers, by the 3kVcc bus bars of the Electricity Substations (ESS).

At the ends and along the entire section there are protection devices that, following the detection of a fault, disconnect the power supply by opening the high speed circuit breakers pertaining to it.

In order to increase the power supplied by the ESS to the section and at the same time retain the characteristics of reliability and security of the protection, the ASDE system is used, which involves the use of interlocking equipment in correspondence to the disconnector parts that supply electricity to the sections of the contact line (hereafter CL).

ASDE3: il sistema di asservimento di terza generazione utilizzato da RFI per la protezione e la gestione degli interruttori extrarapidi a 3000 Vcc

The ASDE units are interconnected to each other by a reference circuit consisting of a telephone pair traversed by a direct current and on which any voltmetric protection devices that may be present in intermediate positions of the CL are abutted.

The intervention of only one of the connected protection devices creates the break in the reference current on the telephone line and, through the interlocking system, the consequent opening of all the high speed circuit breakers that power the section concerned.

In addition to detecting errors on the line and transmitting the circuit break, the new ASDE is able to:

  • Record the events on a non-volatile memory;
  • Perform self-diagnostics and report an alarm in case of failure;
  • Interface to a service PC for maintenance and testing functions (configuration, supervision, updating of the firmware).

ASDE3 Apparatuses

In order to guarantee the characteristics of galvanic isolation, ASDE3 was designed in two distinct apparatuses:

  • ASDE3-SE: dialogs with the ASDE3-LT and interfaces with the field through a set of discrete I/O signals, with an RTU system and, if necessary, a Digital Protection system. It is normally placed at the transformation/distribution plant.
  • ASDE3-LT: its primary function is to power the dedicated telephone pair and dialog with the SE device; it is galvanically separated from the previous one by means of an optical fiber with a capacity of up to 5 km. It lies outside the floor mesh of the processing/distribution plant (usually in the telecommunications cabinets in the railway stations), or it can also be housed in ESS, inside the ASDE-3 device, while nonetheless maintaining a portion, albeit limited, of separation in optical fiber.
ASDE3: Schema funzionamento

In the first case we speak of distributed configuration, in the second case of compact configuration.

ASDE3: Schema funzionamento

The ASDE module is installed adjacent to each high speed switch (2 or more for each ESS), outside the power supply cell in the low voltage compartment and through a dedicated line it communicates the status of the switch to the ASDE located at the other end of the section so the ASDE operates accordingly.

The ASDE3-1 and the ASDE3-5 of the ESS B are said to be "interconnected".

The ASDE3 A-5 of the ESS A and the ASDE3 of the ESS B-1 are said to be correspondent.

An alarm situation, which causes the opening of the high speed switch at one end of the section (e.g. via the ASDE3-5 of the ESS A), is transmitted both to the other extreme of section, where ASDE3-1 of the ESS B controls the opening of the high speed correspondent switch, and to the interconnected ASDE3-1 on the adjacent section, in the same ESS A.

ASDE3: Schema funzionamento

Technical Specs

Feature Reference Values
Dimensions (l*h*p) mm 383x316x166 mm (compact version)
Material PC Cabinet with anodized aluminum panel
Weight 5,8 Kg
Management Port Interface (PG) 1 IEC 60870-5-101 (RS232)
PC communication Interface 9600 Kbps, galvanically isolated
Ethernet 2 Interface IEC 61850 protocol
Current interface One master/slave 20/30mA, 120 Vdc (max= 46mA)
Discrete Inputs 24 galvanically isolated
Relay outputs 17 having a capacity of 8A. Rated voltage 132 Vdc. Breaking capacity 0.2A/132Vdc. Mechanical life 106 operations.
MS relay output One with capacity of 12A. Rated voltage 12 Vdc. Breaking capacity 1.5A/140Vdc. Load 150W L/R = 50mSec. Mechanical life 60,000 operations.
LED Indicators 17 integrated indicators on polycarbonate panel
Pushbuttons 10 + 2 (reset) integrated switches on polycarbonate panel
Selector switches One (ASDE2/ASDE3 emulation) internal
Time Stamping Capacity 1 ms
Date clock Perpetual, automatic, 2- year reserve, precision ± 5 ppm.
Depth of events archive 500 events
Oscilloperturbography Max sampling frequency = 50 Hz Non-volatile memory. Recording with time stamp of changes in selected I/O signals. Total recordable variations: 500.
Operating Temperature Min ÷ Max: -10 ÷ +55 °C
Storage Temperature Min ÷ Max: -25 ÷ +70 °C
RH Min ÷ Max: 5% ÷ 95%

Compact Mode

Power Supply voltage Rated: 132 Vdc
Field of Operation Min ÷ Max: -30% +15%
Draw Rated: 30 W

Distributed Mode

Power Supply voltage Rated: 132 Vdc (ASDE3-SE)
Rated: 230Vca, 50Hz (ASDE3-LT)
Field of Operation Min ÷ Max: -30% +15% (ASDE3-SE)
Min ÷ Max: -15% +10% (ASDE3-LT)
Absorption Rated: 15 VA (ASDE3-LT)