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Find out what you need to do if you want to help us develop the high-voltage grid and replace facilities.

Commodities

Elia orders a lot of work in connection with developing the high-voltage grid and replacing facilities. We order both civil engineering and electrical work, and the assignments we place with contractors mainly relate to high-voltage substations, lines and cables.
A European qualification procedure has been launched for the following commodities:

1 Civil engineering – lines

This category covers work on the foundations of the structures supporting overhead lines, namely concrete and lattice pylons. The work may relate to existing foundations or new foundations and depends on the type of support structure, the load and the nature of the terrain:

Foundations based on footings

Deep foundations (micropiles, drilled foundation piles, tubular screw piles)

2 Electrical work – lines

This category covers electrical contracting work on overhead lines forming part of the high-voltage grid. The main activities carried out in this connection are:

Erection, assembly, upgrading and adaptation of metal and concrete pylons

Line work, which may or may not require the use of puller-tensioners – this includes pulling and replacing conductors and earth wires, beacons and OPGWs

Intrinsic safety

Audit and inspection of metal pylons

3 Civil engineering – substations

This category covers construction work on high-voltage substations and includes foundation-casting, installation of technical building systems, demolition, excavation and all other earthwork, worksite preparation and clearance, electrical wiring, connection to utilities, surface coating and clean-up.

4 Electrical work – substations

This category covers the installation and inspection of the electrical equipment and accessories found in low-, medium- and high-voltage substations. It includes work on lighting systems, controls and connectors, connection of high-voltage equipment, installation of cabinets, installation of cells, laying of low-, medium- and high-voltage cables and work on interconnections and bays. This work category is divided into a number of sub-categories, which are based on the voltage level:

MV/36 kV

70kV, 110kV, 150 kV

220kV, 380 kV

5 Cable work

This category covers the installation of underground cables between and inside substations, which requires considerable expertise in the following activities: cable-pulling (incl. HV, signalling, fibre-optic, drainage), excavation and backfilling (incl. trench-digging and demolition), joint work, restoration work, and more.
The pulling and laying of cables is governed by general and specific technical specifications, which can vary from one infrastructure project to another. Elia has a number of sub-categories for cable work, based on the following voltage levels:

MV, 36 kV, 70 kV (excluding fibre-optic cables)

70kV (including fibre-optic cables), 150 kV 2,000 mm² (including fibre-optic cables)

150 kV 2,500 mm², 220 kV

380 kV

6 Fibre optic work

This Elia work category covers the laying of fibre-optic cables and the associated installation, blowing and measurement activities, as well as the management and maintenance of the fibre-optic network and preventive and corrective actions inside substations and on the overhead and/or underground connections linking the substations.
Fibre-optic cables are laid for the transmission of electrical power through distribution and telecommunication lines that are also used to transmit data and information.

7 Painting work

Painting work accounts for a significant share of the refurbishment and maintenance activities carried out on Elia’s HV electricity infrastructure, and is divided into two sub-categories:

Painting work on electricity pylons

Painting work in substations

8 Pruning work

Pruning and felling around high-voltage lines and maintenance activities on the bases of pylons supporting high-voltage lines are contracted out to approved service providers, who do this work on Elia’s behalf.