Text Eva Augsten and Joscha Duhme ––– Photography
The flat plains of northern Germany. The sky is cloudy. The wind is blowing. It’s not particularly pleasant. In fact, it’s fairly grim. Not ideal conditions for a spot of climbing, right? Hauke Reimers disagrees. The head of Electrical Product Engineering at Senvion GmbH is in his element. Wind, or rather wind farms, are his thing and a way of life for him and his 4,500 colleagues at the global company based in Hamburg. That is why he is trudging down a track early in the morning, almost 30 kilometres from the nearest city and with a safety helmet on for good measure. Rotating above his head with a diameter of 114 metres is the enormous rotor of a 3.2 megawatt turbine. “That’s how it should stay,” says Reimers.
Given the remoteness of the region, it is absolutely crucial that the technology can be relied on. There is no room for error. “Quality and durability are essential in our plants,” says Reimers. Senvion uses cutting-edge communications to keep a close eye on its turbines from the Turbine Control Centre (TCC) in Osterrönfeld. “It’s not all that far away, in Schleswig Holstein, but it is by no means a regional control centre. Information from wind farms in Canada, Australia and the North Sea is routed to the TCC,” explains Reimers, as he folds open his laptop inside the tower. Technical experts from Senvion around the world are issued with jobs whenever the TCC is unable to resolve problems via direct computer access.
The horror scenario – shutdown
Out in the back of beyond, it becomes only too clear just how important every single part is to the operational reliability of a wind turbine. Even minor faults can culminate in a shutdown, and every day of a shutdown means thousands of euros in lost income. “That is why we check all components extremely thoroughly when they arrive in our production plant and then leave the factory,” says Reimers. That also applies to the enclosures from Rittal, which are in use at many Senvion plants, where they house control and monitoring equipment.
Standing at the foot of a narrow ladder, the specialist is meticulous as he runs through all the checks designed to make sure he doesn’t fall. He and his colleagues all have to undergo regular safety training. He quickly climbs the rungs up to the gondola, where five bayed enclosures house the inverter – the electronic heart of the wind turbine. “This converts the electricity generated from the wind to the correct frequency so that we can feed it into the grid,” explains Reimers. In this application, it has proven especially useful that the standard TS 8 enclosures from Rittal can be extended with the flexibility of a modular system and bayed in all directions, whether side by side or back to back. Reimers continues: “This standardisation is a huge advantage when it comes to extending the enclosure combination to suit the size of the inverter. Everything can be done with minimal outlay.” Thanks to the triple-layer surface treatment (nanoceramic primer, electrophoretic dipcoat and textured powder coating), they are also extremely resistant to corrosion and damage. This means the enclosure system can be used worldwide – whether the turbines are standing in snow, the tropics or the high sea. Even in Northern Germany, where conditions are not quite so extreme, the microcontrollers, semiconductors, fuses and contactors are all perfectly protected from humidity, dust and fluctuating temperatures, as Reimers confirms on site.
Regardless of the often inhospitable conditions in which they operate, all wind turbines have one thing in common – their gigantic rotors are constantly generating vibrations. “That makes it all the more important to protect the electrics from reverberations,” points out Reimers. To do just that, Rittal has developed a variant of the TS 8 enclosure that features a mechanically reinforced mounting plate and lock. This reinforcement stops vibrations from triggering oscillation inside the enclosure, which could, in a worst-case scenario, continuously build up.
Wind turbines are always online
These protective measures are also applied to the top box, one of the most important enclosures in a wind turbine, located towards the top of the gondola. It is responsible for monitoring the drivetrain and controlling the rotation of the gondola. “The top box and bottom box are constantly sharing data and also communicate with the TCC.” However, the wind turbines don’t just communicate with the control centre when there are problems, so that specialists like Reimers can put things right. They also transmit key operational data such as wind speed, the amount of electricity generated and the temperature of the gearbox. “That is becoming increasingly interesting from the viewpoint of preventive maintenance,” explains Reimers. It means wear parts can be replaced at precisely the right time – including the fan-and-filter units in the enclosures. These units have to be replaced several times during the 25-year service life of a wind turbine, and that is Reimers’ job for today. The more precisely the changeover date can be specified, the fewer fans will be needed over the course of the wind farm’s service life and the more effectively maintenance costs can be reduced.
Rittal offers a potential solution. Fan-and-filter units with EC technology are a sound choice for efficient operation and the option of fan monitoring. They exhibit lower power consumption and feature an integrated control interface as standard that can be used to control the fan and monitor its speed and functionality. The end result is a fast and simple means of detecting fan failure and even better operational reliability.
Senvion adopts the same approach in prototype development, as Reimers explains while he completes his inspection. The company is planning to use Blue e+ cooling units to achieve more accurate temperature control at the wind farm. That would, in turn, allow it to extend its remote monitoring and predictive maintenance. Since the Blue e+ units can be allocated an IP address, Senvion can map out measured values from the sensors in the cooling unit remotely, as and when necessary. This allows the company to evaluate system notifications, maximum ambient temperatures, minimum enclosure internal temperatures, duty cycles and capacity utilisation. Cooling units can thus become an integral part of Industry 4.0 concepts, which improves service, optimises operation and generates savings.
The technical experts at Senvion shouldn’t then have to venture out into the wilds as much as they have had to in the past. The innovative enclosure solutions with cutting-edge communication technology from Rittal will help keep the rotors of the Senvion wind turbines turning reliably for years to come, generating clean electricity. That goes for the wind farm in northern Germany, too, where the head of Electrical Product Engineering has corrected the minor component fault, sent all the parameters to the TCC and packed up his things. The wind is blowing. The rotor is turning. And that’s just the way Hauke Reimers likes it.