Maintenance
As the owner of the transmission line, Fingrid has an obligation to maintain the line in the condition prescribed by electric safety regulations. For the maintenance of the line, the company has the right to move in the transmission line area on foot and by using machinery and vehicles, to use roads and paths leading to the transmission line area and to use other areas, if necessary. The condition of the transmission line and the height of vegetation in the transmission line area are monitored with the help of regular inspections.
The inspections of transmission lines are performed either by walking in the terrain or by means of helicopter at intervals of 1 to 3 years.
The inspections are used for observing issues such as
- height of vegetation in the transmission line area, new structures, excavations
- potential inclination of tower structures, condition of steel parts, birds' nests, woodpecker holes
- condition of insulators and conductors.
Furthermore, special inspections are performed whenever necessary. These inspections are used for monitoring for instance decay of wooden towers, grounding systems, insulators and joints. In the winter time, ice load patrols can also be used.
Handling of trees
The operational safety of the transmission line is ensured by clearing the rights-of-ways mechanically at intervals of 5 to 8 years. The clearing is carried out selectively, taking into account scenic aspects, recreational uses of the right-of-way, and biodiversity. Trees in the border zones are cut down at intervals of 15 to 25 year. The border zones are kept tree-proof, in other words, we ensure that a falling tree cannot reach the phase conductors. Overlong trees in the border zones are cut down, or the tops of trees (2 to 4 metres) are sawn off by using helicopter sawing. Decay in trees whose tops have been sawn off progresses so slowly that the landowner does not need to cut down these trees immediately, but they can be cut during the next harvesting.
If trees in the border zone need to be cut, Fingrid aims to arrange joint felling of trees in the border zones so that the trees are felled by professionals. However, as the owner of the tree stand, the landowner has the right to decide how to arrange the harvesting and sales of trees in the border zones cut because of line maintenance. If the landowner wishes to cut trees growing in the border zone on his own, Fingrid should be contacted well in advance so that the landowner can obtain felling assistance free of charge.
