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Basic design and specifications for HVAC and HVDC overhead lines

DNV’s services provide a basis for decisions on technical solutions and layouts for new and renewed HV overhead lines, and for tendering / execution phases

Constructing a new high voltage overhead line is a complex process. It involves many stages: from the first feasibility studies, through specification and bid assessment to final delivery and acceptance. Often, projects require great technical insight and state-of-the-art knowledge to develop tailor made solutions.

DNV's services offer you access to this level of insight and knowledge, covering all aspects of the latest technologies – electrical, mechanical, structural and civil.

As an expert player in the field, we are involved in numerous projects every year, ranging from medium to the very highest voltages, AC and DC. Plus, we have advanced skills in power line system software tools. All this means, we can provide you with technically sound advice at every phase of your overhead line construction project.

New overhead lines
Building new high voltage power links is an unavoidable necessity for many utilities. Moreover, these links need to be socially acceptable and financially efficient, as well as technically reliable. We help you address all these issues, and we bring experience of developing innovative designs with low magnetic and electric fields and visually attractive towers.

Our methodology for high voltage lines can also be used for large industries that require a high voltage grid.

Upgrading and uprating existing overhead lines
When end users demand more power, it may be necessary to increase the transmission capacity of existing power links. In this case, we provide you with methods to uprate and upgrade high voltage overhead lines. These can include increasing the current (for instance by using HTLS conductors), moving to higher voltages and / or switching from AC to DC.


  • Feasibility studies
    • Detailed analysis of the technical and economic feasibility of a new or renewed overhead line
  • Conceptual design studies for innovative overhead line and tower designs
  • Line routing and tower spotting
  • Preparation of  designs and specifications for tendering
    • Subsequent tender evaluations, quality assessments, quality control, review of detailed design, and related services

These activities include:

  • Brainstorming and design sketches
  • Definition of the (preliminary) Terms of Reference and basic requirements
  • Preliminary design of tower families
  • Selection of a tower family
  • Design of foundations, towers, conductor & insulator configuration, clamps and fittings, vibration damping
  • Preparation of specifications
    • for supply  of all components and for construction of the line
  • Determination and assessment of magnetic and electric fields and audible noise profiles
  • Vibration analyses
  • Visual impact studies