Maintenance and construction in practice

ČEPS has implemented an internal technical standard known as "Preventive Maintenance Code for Electrical Installations within the Transmission System" which is a basic regulation for inspecting and maintaining the installations and equipment within the ČEPS transmission system.

The Code specifies the following maintenance periods: walking inspection including tower leaning inspection to be carried out annually, or for undermined areas twice a year; protected bands inspection focused on vegetation conditions and height to be carried out annually; aerial visual power line inspection every three years; aerial visual inspection using UV-diagnosis to be carried out not later than one year after new or renovated power line has been launched in standard operation; aerial thermo-visual inspection to be carried out one year after the construction has been completed and subsequently every six years; detailed visual above-ground inspection of tower constructions every five years or twice a year in case of towers located on undermined areas; extraordinary above-air inspection following extensive repair works or based on the outcomes of other inspections, standard inspection carried out based on inspections, earthing measurement to be carried out once in 10 years; repeated earthing measurement as scheduled.

Additional maintenance work is carried out with respect to the equipment condition, in particular protected bands maintenance focused on eliminating vegetation over 3 m of height (as required by the law), tower placement maintenance focused on field works carried out within the ground plan of shanks around concrete to ensure the transmission of steel web into the concrete base, tower construction painting to restore anti-corrosion protection of the construction and a number of other minor repairs or replacements of power line parts.

 

Construction of new power lines

The construction of new lines is governed by legal regulations concerned with the preparation and execution of line construction projects. All the relevant rules covering construction by the Company, including environmental impact assessments (EIA), are meticulously followed. This also applies to new lines built alongside existing lines. A balance between conserving the natural environment and landscape and the most feasible or most technically and economically advantageous solution for the Company and its customers is always sought when preparing a new power line project.

 

Construction execution

Towers or their individual segments are assembled on-site and then erected using either the gradual extension method, i.e. stage-by-stage assembly, or the tilting method, when a completely pre-assembled tower is erected by crane. In inaccessible areas, helicopters are used to erect towers. Insulators are installed on towers using simple but ingenious and highly reliable hoists.

Conductors (phase and ground wires) are transported to the site on reels (drums) each with an average weight of 3 tons and strung on the towers using special stringing machines (pullers and tensioners).

The time of construction of a line section, from excavation of tower foundation holes to site reclamation after construction completion, is typically no more than 3 months depending on the route section within which the power line is built and the particular region. Except for the tower construction itself, no heavy building machinery or other equipment for which special access roads have to be constructed is required. No plant depots or temporary stores for materials need be built on or near the line construction site; the construction schedule is designed to fully take into account the natural growing cycle and local farmland use.

Brochure: Construction of power lines for download

Video of formation the substation Kletné for download.