Standards for 400 kV power line poles

Eltel Networks‘ task was to develop a detailed documentation for a series of standard 400 kV power line poles in the wind load zone W2 and the icing load zone S2, as well as in the wind load zone W1 and the icing load zone S2. The ordering party commissioned us to design poles for double-circuit and single-circuit lines.

The design work was preceded by the development of a design solutions concept, as a result of which the final number of designed poles included in the W2S2 and W1S2 series, as well as the range of designed poles and the basic assumptions for their design were determined. The ordering party reserved the right to make ongoing arrangements with us regarding the assumptions of the designed poles specified in the concept. The number of pole types for which detailed documentation had to be developed was 37 in total (including single-circuit poles), and at least 5 height versions were planned for each pole type. One of the designed models of the double-circuit pole of the 400 kV line turned out to be a real record holder in terms of height and weight of the structure – it is almost 140 m high and weighs 211 tons of steel. Additionally, as part of the order, #EltelNetworksTeam:

• developed complete documentation of designed poles for the needs of line construction projects to be based on designed poles, including: technical description, assumptions used for calculations, main load systems, pole profile, calculation results, maximum strength of bars, values of maximum reactions on foundations
• carried out load tests on two poles (S2W2 series), i.e. 1 through pole and 1 strong pole for double-circuit 400 kV overhead power lines, including their construction and control assembly, transport to the research station, assembly supervision and the tests at the station, along with the reports preparation on poles load tests.

It should be emphasized that the poles load tests were performed in accordance with the test specifications developed by the Contractor and the load test programs that were developed by representatives of the research station at the Contractor request. All designed structures comply with the standards of PN-EN 50341-1:2013-03, PN-EN 50341-2-22:2016-04, PN-EN 50341-2-22:2022-06 and customer specification standards.

The entire scope of the contract was a serious challenge even for the leading design office in Poland, which is Eltel Networks Engineering SA. The work was carried out for a key client, i.e. Polskie Sieci Elektroenergetyczne. Despite complications related to the Covid-19 pandemic and organizational difficulties, we completed the agreed scope of work fully professionally and successfully.
All tasks were performed in accordance with the requirements, contract and applicable standards. The investor has accepted the ordered scope of work, and the designed poles will be used to expand the National Power System.

The end result of our work was the performance of an investment task enabling the transfer of power energy from offshore wind farms to the National Power System. PSE plans to use the executive designs developed by Eltel Networks in the implementation of the following investment tasks:

1. Construction of a new 400 kV substation near the 400/110 kV Żarnowiec substation with the introduction of the 400 kV Słupsk – Żarnowiec power line.
2. Construction of a 400 kV power line from a new 400 kV substation near the 400/110 kV Żarnowiec substation to the intersection of the 400 kV Gdańsk Błonia – Grudziądz Węgrowo power line.
3. Construction of a 400 kV power line from a new 400 kV substation near the 400/110 kV Żarnowiec to Gdańsk Przyjaźń substation.
4. Reconstruction of the 400 kV power line from a new 400 kV substation near the 400/110 kV Żarnowiec substation to Żarnowiec into a double-circuit 400 kV line.
5. Construction of a 400 kV power line Dunowo – Żydowo Kierzkowo – Piła Krzewina.

The pictures below show:

• an unusual lattice model using multi-branch elements, necessary due to the magnitude of the transferred forces
• spatial model of the curb connection node in a multi-branch system checked in BIM software
• node stress map for strength analysis of the lattice tower.