Changes made to civil aviation regulations in 2014 resulted in a requirement that Statnett install thousands of markers on existing transmission lines by October 2019. The primary method being used to install markers in Norway at the time was with a line cart. Due to the large volume of work and deadlines given, a review of installation techniques being used around the world was carried out.
The ideal solution would: reduce or eliminate the need for work at height, install 10 or more markers a day and be cost competitive. It was a requirement that any solution used be compatible with markers designed to meet demanding Norwegian climatic conditions. It was concluded that, together with other initiatives, a robotic solution should be investigated.
Design work was focused in three main areas:
- Marker clamp mechanism
- Marker – robot interface
- Robot design
Time and cost restraints were a significant factor in many design decisions. Close cooperation between a robot supplier, two marker manufacturers and Statnett was a critical factor in the success of the project.
In November 2016 a full-scale prototype robot was tested. The prototype robot was able to install a marker, but significant changes were required to make the solution practical and effective. In 2017 testing of a next generation robot was carried out and in 2018, after further improvements, the solution was taken in use by contractors.
Over 300 markers have been installed on Statnett transmission lines using robots. Work is ongoing to establish if the solution can be used on shield wires over live phase conductors. A spin-off project to develop a de-installation robot is being considered.