Transmission lines

Transmission line services

Despro provides expert services and competent know-how for every stage of transmission line life cycle from planning to construction and maintenance.


Construction management



Transmission lines

Transmission line design

Our carefully implemented transmission line design process is based on expertise and provides clients with indispensable information to support investment planning. At the construction phase of transmission lines, we take care of client’s interests, ensuring that the project is carried out cost-effectively and on the schedule. Our know-how and expertise ensure high quality and safe implementation of the project at its all stages After construction of the transmission network, we provide our clients with maintenance and condition inspection thereof.

Our services are nationwide and tailored to cater for every client’s case-specific needs.

Route planning and environmental survey

In route planning, we map and consider nature conservation areas, museum sites and distances to buildings, narrowing down from all possible options the best one. If necessary, we carry out an environmental survey, mapping the natural values of the transmission line area and assessing the effects of transmission line with the help of magnetic field estimates and reports.

Negotiations with authorities and statements

On behalf of the client, we hold official negotiations and obtain statements from the necessary parties such as Centres for Economic Development, Transport, and the Environment (ELY), regional administrative agencies, Heritage Agency, Regional Council, Finavia, the Finnish Defence Forces, local authorities of municipalities and cities, and the Finnish Transportation Infrastructure Agency. We are responsible for negotiations in situations where changes are wanted to the planned route. We take responsibility for research permit applications and apply for research permits from the National Land Survey of Finland in order to be able to work in the area. We submit a project permit application to Energy Authority, grounding the reasons and importance of the construction of the transmission line.

Transmission line route mapping and investment planning

We map the cable route with GPS equipment, open the centre line of the transmission line route and mark the planned pole locations on the terrain. In the investment planning phase, we use data to design the profile of the cables – for example, the distances of the poles and the cable suspension towers are modelled in the map file.

Soil investigation

Soil investigation is carried out using vibration or pressure drilling. Based on the reported soil layer, bedrock, and groundwater levels we make recommendations for the foundation method for the poles.

Hazard and interference voltage reports

We carry out inspections and investigations of hazards and interference voltages. The calculation quantities we master include, for example, equivalent grounding impedances, reduction factors and calculated induced voltages. In our statements we map how transmission lines affect the surrounding land area, and the electricity and telecommunications network. Statements present measures, how to identify hazardous objects and implement protective measure setting thus foundation for grounding design.

Soil resistivity measurements

We perform measurements of the soil resistance in the terrain. Grounding design is based on measurement results giving our experienced measurers required expertise to make the necessary observations about objects that have to be considered in terrain planning. During the same measurement, we can, if necessary, collect and prepare maintenance or location information.

Transmission line structures

We design the transmission line pole types and determine which pole type should be used at each pole location -considering strength requirements and constructability. We also determine the fibre and conductor types to be used.

Expropriation procedure

We take care of pre-expropriation negotiations with landowners and prepare expropriation permit applications. We represent our clients during the expropriation process and participate in the expropriation process meetings in the capacity of expert. We determinate soil types and estimate forest stand for expropriation. We mark logging and property boundaries in the terrain.

Transmission lines

Transmission line construction

Work management

In the capacity of client’s constructor, we are responsible for work orders and schedules, approving invoices, site supervision, and for checking terrain plans. We participate in meetings at the transmission line site during the contract period and check the work documents prepared by the contractor regarding its work. If necessary, we also handle complaints on behalf of the client and the indispensable communication with landowners and authorities.

Work site supervision

We monitor both the quality of construction and the implementation of safety at the construction site and report thereof to the client in accordance with the agreement. We handle the duties of the statutory safety coordinator at the construction site and carry out construction site inspections. We brief and guide contractors in questions and work procedures related to the construction site and commissioning.


We take care of the clearing of trees and vegetation on main route, and of processing the border zone according to the expropriation permit. During clearing and tree–cutting we also take care of the sale of the landowner’s timber and the related communication with parties involved.

Final inspection

After the construction site is completed, we check that the transmission line has been built as agreed. If defects are found on the construction site, the contractor will be notified thereof, and an agreement will be made on scheduling the repair.


We document changes made after construction of the transmission line in the client’s system and update the documents to reflect the existing situation. We also document and update the data of the existing electrical power grid and check that the power grid described in the system corresponds to the situation on the terrain.


We carry out GPS location measurements and inspections of the power grid during the construction, after the construction and for updating the documentation of the existing network. We can also mark the pole positions before starting the construction.

Transmission lines

Transmission line maintenance

Transmission line maintenance

Maintenance services

In connection with maintenance inspections of the transmission lines, we check the compliance of the components of the power grid, the correctness of markings and the possible need for repairs. We check whether the observations about the terrain and the power grid match the data recorded in the system. We will update the information, if necessary, or provide the client with a listing, which can be implemented at client’s own discretion.

Maintenance planning

Our maintenance planning provides solutions in situations in which the need for renewal of components related to transmission lines is detected. We evaluate the need for renewal and provide our clients with an overview on the cost-effective implementation of the grid renovation: different options with cost effects and schedule estimates. Maintenance plans may also be done for individual and in more limited scope.


We take care of the clearing of trees and vegetation on the main route and processing the border zone according to the expropriation permit. During clearing and tree-cutting we also take care of the sale of the landowner’s timber and the related communication with parties involved.

Efficiency in all phases of the transmission line life cycle

In our work, we use, among other things, the following network information systems:

  • AutoCad

  • BasePower

  • Microstation

  • 3Dwin

voimajohdot janne despro

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How can I help?

Janne has long experience in responsible positions in the transmission line business. If you can’t determine your need yourself, he will find out with a few questions.

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Brief in English

Despro provides professional services for energy and telecom industries. We offer our services for network construction companies, network owners and other stakeholders