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Drags System

The feeder system is responsible for the management of the opening signal of an overspeed in a substation to allow the transmission and subsequent opening of the corresponding feeder overspeed in other collateral substations, which could supply the same traction sector, and all this in the shortest possible time.

The elements that make up this system are:

  • Traction equipment
  • Communication of the traction signal
  • Management of the traction signal

Dragging equipment

Its function is to detect the opening of an extra-rapid of a substation, to transmit this information to the substation that supplies the traction line collaterally in order to allow the opening of the corresponding extra-rapid in the shortest possible time.

Signal communication

The establishment of the communications signal between collateral trawl equipment is carried out via the general single-mode fibre optic cable installed along the line or via a fibre cable laid between these substations for this purpose.

Communication between the automaton in charge of trawl management and the automaton that manages the substation control is carried out by means of three types of signals:

  • Reception of trawling
  • Transmission of dragging
  • Communication failure

This communication will be carried out through the wired inputs and outputs. There is also the possibility of having the signal Inhibition of trawling, which will inhibit the transmission/reception of trawling from the collateral substation.

Drag signal management

On receipt of trawls, the following measures are taken provided that the trawling equipment is not inhibited:

  • A trip is generated with reclosing to the feeder affected.
  • If the by-pass disconnector of said feeder is closed, the rest of the bypasses are checked and trips are generated with additional reclosing to those feeders that do not confirm that their disconnector is open.

A trigger emission is generated by the corresponding feeder when any of the following signals occur and provided that the trawl equipment is not inhibited:

  • Triggering by static or maximum intensity on feeders.
  • Maximum or minimum DDL trip on feeders.
  • Ground Detection.
  • When an attempt is made to manually parallel two feeder outputs.
  • When the emergency stop button is activated.
  • When the DC gates are opened and tripping is not inhibited.
  • When the DC earthing switch is closed.
  • Earth rail voltage trip without the trip being inhibited.

The operator, from the Control Post (Energy Remote Control), will have the possibility of inhibiting the emission and reception of drags by each of the traction sectors, being able to block them from the remote control in order to avoid incorrect orders. In the substation itself, there shall be a selector with two positions to activate/inhibit pulls, per traction sector.

Depending on the operating mode of the substation, local/distance, the information received from the remote control or from the substation itself will be taken into account.