HÖRMANN Kommunikation & Netze upgrades 110-kilovolt cables
In 2019, HÖRMANN Kommunikation & Netze carried out modernisation work on two 110-kilovolt cables in the Frankenthal area on behalf of Pfalzwerke Netz AG. The company’s work to replace pylons and conductors met with glowing feedback. As a result, it was invited in late 2019 to submit a tender for further projects in 2020, to be divided into three lots. HÖRMANN Kommunikation & Netze was given the contract for lot 2, with the range of services involved increasing considerably following initial talks.
The 110 kV cable project designated ‘SW Miesau – UW Bruchhof’ included replacing the phase conductors and upgrading them to bundles of two (that is, two conductors per phase) and replacing a fibre-optic earth wire, meaning a data cable doubling as a means of lightning protection. The route involved was around 11.3 km long and featured 47 pylons.
Work carried out:
- Disconnecting 280 cable hold points
- Installing and removing 280 stringing blocks
- Stringing 136 kilometres of conductors and setting them into their end positions
- Stringing 12 kilometres of fibre-optic cable
- Reconnecting conductors after setting
- Installing roughly 2,000 conductor spacers with maintenance cradles
Two things in particular made the project special.
Strenuous efforts had to be made during the work to protect nearby buildings, roads and railway lines against any risk of the conductors falling down. Around 230 roller hangers were used for this. An additional retaining cable with track rollers was inserted into the existing conductor and used for safe conductor replacement.
Three overhead line maintenance cradles were used to install the approximately 2,000 spacers between the two overhead conductors in the phases once the conductors had been restrung and set. A clever mechanism assisted by a hydraulic arm on each maintenance cradle made it possible to drive the cradles over the suspension insulator sets. Each maintenance cradle’s drive unit was swivelled outwards while the cradle passed over a suspension insulator set and then brought back in to allow it to continue propelling the cradle along the conductors. Each maintenance cradle weighs just 220 kg and is driven by a hydraulic system powered by a 125 cc Honda engine producing five metric horsepower. It is designed to carry one person with a total payload of up to 200 kg and has a top speed of 4 km/h.
There were 12 to 20 employees on-site throughout the duration of the work, running from May to the end of September 2019. Preparations are already under way for another stringing operation near Mutterstadt and a pylon replacement project at the Mercedes-Benz proving grounds for our customer Pfalzwerke Netz AG.
