The picture shows two employees from Stadtwerke Tübingen moving a cable drum with a heavy-duty crane.
At the depot, cable drums are moved with a heavy-duty crane.

Situation meeting at the Tübingen municipal utilities: Michael Ludolf and his technical service employees go through the work that needs to be done. A team is currently travelling to the neighboring town of Ammerbuch, where they want to connect the prototype of the VOLTAP battery draw charging station developed by the municipal utilities to the local power grid. As in recent weeks, other foremen have been working on renewing the cabling of old transformers in the Tübinger city area. “Everything is on schedule”, compliments Ludolf, who, as Head of Technical Service, together with his team of foremen and fitters is responsible for operating the power grid in the city of Tübingen.

E-mobility challenge

In normal years, the municipal utilities install around ten kilometers of medium as well as low voltage cables. For large projects, such as when a new industrial park is connected, it can be several kilometers at once. The installation teams from the public utility then dig up roads and pavements and pull the cable into rodent-proof pipes. E-mobility in particular will require an expansion of the power grids over the coming years. In Tübingen, however, they are well prepared. “We are well positioned in the medium-voltage network”, Ludolf says, “reinforcements are needed primarily in the low-voltage network”.

When the municipal utilities in Tübingen lay new cable lines or replace old cables, as it is currently the case in some old transformer stations, you can assume that most cable drums come from LAPP. The global market leader for integrated cable and connection systems supplies a large proportion of medium and low voltage cables. Once a year, Ute Jung, who is responsible for purchasing at municipal utilities in Tübingen, writes out the quantities of cables that will be needed over the next 12 months with surcharges always going to LAPP. When the construction work begins, Jung retrieves the cable provided for this. LAPP then delivers its cables to the depot on Eisenhutstraße. Just-in-time delivery directly to the construction site, as LAPP is doing for other projects such as the construction of wind power plants. is not necessary in Tübingen. “At the depot, we have more space and a heavy-duty crane, which makes handling easier for us”, said Jung.

The picture shows two employees from Stadtwerke Tübingen showing a cable with an aluminum core.
Insight into the cable with aluminum core, a cross-section of 150 square millimeters and a robust PE outer sheath.
The picture shows a cable drum hanging from a heavy-duty crane.
Stocks at municipal utilities of Tübingen are being increased in order to modernize the power grid

Supply chains under pressure

This warehouse could play an even bigger role in future. As a result of the coronavirus pandemic and the war in Ukraine, supply chains for many products are under pressure. “Delivery times have been longer”, states Ute Jung. Possible outages are to be counteracted by increasing warehouse stocks. They can rely on their suppliers. “There have never been any problems with delivery at LAPP”.

Medium-voltage cables are often needed. The cable consists of an aluminum core with a cross-section of 150 square millimeters and a robust PE outer sheath. Three of these cables are always twisted together, i.e. twisted into a bunch. This benefits electromagnetic compatibility as the electromagnetic fields of the three cables cancel each other out. LAPP supplies the cable fully stranded on drums with a diameter of 2.50 meters, from which the strands are unreeled and pulled through an empty tube underground.

Set as the supplier

LAPP and the municipal utilities in Tübingen have been working together for more than 15 years. Michael Ludolf, who has been at the company since 2012, can’t remember a pre-LAPP era. “We are very satisfied with LAPP and we use these products regularly”, confirms Ute Jung. Only where LAPP does not have a certain product on offer were other suppliers brought in – whereby they had to orient themselves by the high-quality standards offered by the global market leader.

Quality is the key to choosing suppliers. It is not uncommon for the cables to lie in the ground half a century or longer, but under the streets of Tübingen there are still many from the 1960s or 1970s. “As a company, we cannot afford to carry out experiments in terms of security of material supply. A cable can’t break after ten years”, emphasizes Michael Ludolf, “and with LAPP we know that we are getting the best quality”.

The picture shows an employee from Stadtwerke Tübingen moving a cable drum with a heavy-duty crane.
LAPP supplies a large part of the medium and low voltage cables for the municipal utilities of Tübingen