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Installation and renovation
of high-voltage substations

From design to operation, Dorsalys develops a multi-technical turnkey offering covering installation and renovation of HVB substations, which are essential elements in the transmission and distribution of electricity.

Our experts adapt to meet their customers’ needs, while making their expertise and experience available in order to offer them a fully tailored response.

Substation engineering and design

More than 50 employees work at our specialist design offices, where their role is to offer expertise, analysis and consulting.

They manage the administrative processes involved with construction, and design every aspect of your project: civil engineering, electrical calculations, digital instrumentation and control, testing procedures and commissioning.

We develop custom substation monitoring based on your choice of brands and products and customise the interface.

To ensure the optimum possible use of HVB substations and to guarantee both their reliability and availability, our experts incorporate the needs of operational and maintenance teams from the beginning of the project.

Our strengths are in-house development of a digital instrumentation and control system, and monitoring.

Hugues Derycke Substation director France Europe Northern Area

A fine example of Eiffage Énergie Systèmes' synergy to offer a complete solution to our customer Boralex

Installation of HVB substations

HVB substations

Dorsalys takes care of the work, the testing and the commissioning of equipment.

Our regional locations mean we can offer you presence and responsiveness.

We conduct civil engineering works that are essential to the site: foundations (masses, slabs, etc.), pits for transformers, containment pits, roads and utilities (gravelling, drainage, retention basins) and fences. 

In our workshops, we manufacture metal frameworks (gantries, equipment supports) and instrumentation and control cabinets linked to SCADA monitoring, as well as the LV equipment that is to be connected. 

In addition, we manage the supply, installation, connection, and commissioning of HVB equipment of between 63kV and 400kV (power transformers, disconnectors and circuit breakers, etc.) and HVA equipment of between 5kV and 33kV (auxiliary service transformers, HVA distribution boards, filters, etc.).

During installation and connection work, our earth measurements ensure the protective system operates correctly. 
Such work requires qualified staff, which is why our employees hold NFC18-510 certification and the PASS Haute tension, awarded following training on the electrical risks specific to this work.

Find out more about our training

Commissioning testing

Commissioning testing

Dorsalys carries out performance tests throughout the entire life cycle of your HVB substation.

From the design stage, our experts list the procedures, guides and test files required when first powering up the substation, in conjunction with the network manager.

At the workshop stage, our technicians supervise operations and monitor the control system.

Once the mechanical work is completed, our teams then move on to functional testing of the installations at the site.

At the final stage, substation commissioning tests are carried out to ensure all elements function correctly when powering up.


HVB from 63kV to 400kV and HVA from 5kV to 33kV Equipment managed

  • Over 50
    employees in our design offices
  • More than 250
    Substation specialists in the field
  • 24/7
    Installation management operations

Substation operation

Substation operation

Dorsalys customers can delegate the role of HVB substation operating manager to the company.

This delegation takes place in strict compliance with the RTE Operating Agreement and the decree of 20 February 1992 that sets out specific health and safety rules applicable to work performed on a site by an external company.

The tasks you assign to us are set out in a prevention plan describing the risks linked to the activity, working conditions or equipment used.

During operation, our NFC18-510 (HVB)-certified technicians make sure that equipment is locked out to ensure they can carry out their work in total safety.

This equipment can be managed remotely via SCADA monitoring, or in person with our on-call teams, available 24/7.

The technical analysis and advice provided by our experts can also help you to prioritise your actions following an unexpected event.

Substation maintenance and renovation

Dorsalys can also support you in your HVB substation maintenance and renovation operations from the initial drafting of maintenance plans and task lists.

Our teams work with you to determine the make-up of spare parts, the tasks that are strictly necessary and the intervals at which they should be carried out in order to obtain the best ratio of reliability to maintenance or insurance costs.

Our multi-year contracts offer maintenance operations from levels 1 to 5 (preventative, corrective, predictive) as set out in Afnor standard FDX60-000. And our experts conduct a series of tests and measurements: ratiometer measurements on transformers, SF6 gas analysis and leak detection, etc.  

These services are carried out by HVB-specialist employees who have undergone specific training on the equipment they maintain. 

Because HVB substations must be designed with optimum use in mind, our experts incorporate the needs of operational and maintenance teams from the beginning of your project.

Patrice Hermant Director, Substations division

Find out more about our training

As with operational roles, requesting a 24/7 on-call team will allow our teams to take action immediately should an unexpected event occur.

Our overhead and underground power line offering