Major disruptions in Amprion’s network are rare. That’s in part because fitters carry out regular maintenance work on the power lines. If damage does occur, these troubleshooters are the ones who carry out the repairs – at a truly dizzy height.
A Wednesday morning in autumn and it’s raining cats and dogs. Thick fog clings to the hills of Germany’s Sauerland region. But the 55-metre-high power line pylon is clearly visible. At its base, three company vehicles belonging to Amprion pull up. Hans Brinkers, Klaus Rothlübbers, Jonas-Daniel Glane and Frank Hölscher get out and look around. “Today’s a good day for a swim,” says Hölscher. His colleagues grin.
The four men are overhead linesmen and are used to working outside in wind and weather. Their assignment today: to repair a damaged conductor close to the pylon. Each power line consists of several conductors. One of the strands of a conductor has broken. It’s sticking out and has to be repaired with what’s known as a “line guard”.
Jonas-Daniel Glane doesn’t mind climbing to great heights. While he climbs the pylon, his colleague on the ground prepares the cable trolley for the repair work.
We need to be prepared at all times
Maintaining the power grid network has top priority at Amprion. After all, the power supply of many millions of people stands or falls with the reliability of grid operation. “Our network is robust. Overall, it suffers from very few faults, but despite this, we need to be prepared at all times,” says Hans Brinkers, who is assignment manager. The native Emslander knows his way around. He has been working as an overhead linesman for 32 years. On this autumn morning, however, he and his colleague Klaus Rothlübbers remain on the ground. It’s Jonas-Daniel Glane and Frank Hölscher who will climb the pylon. That’s what they have agreed.
The men put on rain gear, helmets and gloves, then go off to set things up. They move the van and trailer, on which a motorised cable winch is mounted, into the right position. They remove around 100 metres of lifting rope and lay it down in front of the pylon along with other materials. Later, they’ll hoist most of these materials up with the winch. This includes the 200-kilogram cable trolley, a type of cradle they affectionately call “the little chair”. This specialist piece of equipment lets you travel along the overhead cables way above ground level.
“No matter how experienced we are, we can’t afford to be sloppy in this job.”
HANS BRINKERS Overhead linesman and assignment manager
Not for the faint-hearted – Jonas-Daniel Glane climbs from the pylon, via the insulators, to the conductors. This demands maximum concentration.
Is the conductor live?
Jonas-Daniel Glane and Frank Hölscher get into their climbing harnesses. A harness weighs more than ten kilograms. Secured as on a via ferrata (for the uninitiated, a fixed-rope route for adventurous hikers), they climb 55 metres up the pylon. They also carry a non-contact voltage tester in their kitbag, a rod-shaped device they use to test whether or not current is still flowing through the conductor. However, this shouldn’t be the case now, because Hans Brinkers had a few days earlier submitted a request to Amprion’s grid management for this line to be isolated (i.e. disconnected) today – and he has telephoned them early in the morning to confirm that it has been. “We still need to have the testers with us, though. They’re our life insurance,” says Glane. He’s been doing the job for seven years. After several safety checks, his colleagues below hoist up the remaining equipment. Everyone is fully focused on the job. “No matter how experienced we are, we can’t afford to be sloppy in this job,” says Brinkers.
Glane now has to get from the pylon to the conductors. He climbs carefully onto the insulator string. Below him a 50-metre-deep abyss. It’s still raining, and the porcelain insulators are slippery. From below he looks like a tightrope walker. He slowly works his way forward. To slip or stumble here would be dangerous, despite all the safety precautions. But he gets to the spot he wants to be without any problems. He mounts an attachment for the cable trolley between the conductors. The trolley itself now has to be hoisted up – working as a team, with the aid of the winch, using hand signals.
What looks spectacular to the layperson is just part of the job for overhead linesmen. They hoist the cable trolley up to conductor level with the aid of a winch. Hans Brinkers (left) has everything under control. The assignment manager has more than 30 years under his belt as an overhead linesman.
“Our job: hiking, climbing and flying”
After Glane has hooked in the cable trolley, he climbs in and starts the motor. It’s about 300 metres from the pylon to the damaged area. It was discovered in summer, during a helicopter inspection flight. Once a year, Amprion flies along the entire length of its grid and inspects the conductors for damage. In addition, a walkdown inspection of every pylon and conductor is carried out once a year. Every five years every single pylon is climbed up and closely inspected. “We hike, climb and fly – all the things other people do in their free time,” says Glane. There are almost 4,500 pylons in their district – a lot of work for these overhead linesmen. Brinkers alone drives around 35,000 kilometres (22,000 miles) a year. Every five weeks he’s on emergency standby duty for seven days. If a major fault occurs at night, he has to go to the location immediately. “But that’s rare,” he admits.
“We hike, climb and fly – all the things other people do in their free time.”
JONAS-DANIEL GLANE Overhead linesman
Every step must be perfectly executed. Jonas-Daniel Glane assembles the cable trolley, which he calls “the little chair”. He uses it to get to the damaged area 300 metres away.
Glane starts to repair the damaged conductor. While he wraps the damaged section of the conductor in patch rods (repair sleeves) made of aluminium, the other men take a break. Shortly before Glane is finished, he discovers a second damaged section of conductor a few metres further on. He deals with it after completing the initial repair. “There’s no way you could’ve seen the second strand breakage from the helicopter,” he says later. “It was too small and too close to the spacer between the conductors.” What caused these two breakages? “Good question,” says Brinkers. “We can’t say for sure.” Conductor damage can be caused by lightning strikes or defective bundle spacers – sometimes also by hunters accidentally hitting the cables with their bullets.
Repair work completed: line “free of work”
Meanwhile, Glane is on his way back to the pylon in the cable trolley. Dismantling can begin – and it’s still raining. In the afternoon, everything is stowed away again and the men make their way home. Only Hans Brinkers still has one final duty to fulfil. He phones the colleagues in grid management to tell them that the line is “free of work” and can be switched back on. A short time later, electricity flows once again through the repaired conductor.
