One of the largest transformer manufacturers, with 19 factories throughout the world, is Siemens. One of those factories is in Dresden where HEROSE fittings and valves are also fitted. A report.
A transformer is one of those technical devices with a function for which the layman hardly spares a second thought. But it’s not surprising: The large versions are predominantly painted in mouse grey and hidden behind high fences – and the small ones are often not visible at first glance.
However, that which is so often inconspicuous is a highly complex piece of equipment without modern life is unthinkable. Electrical power grids, which would not work without transformers, are one example from everyday practice. Without them we wouldn’t be able to transport power at all – from the source to the consumer. What for power production is a rather low voltage (e.g. for wind farms around 1000 volts) is first transformed to a transportation voltage of 380 kilovolts (kV) – and finally reduced; to the usual main voltage of 230 volts.
A visit to Siemens in Dresden. Around 200 medium-power range transformers (from 10 000 KVA to 200 000 KVA) are produced in Dresden each year – these are exactly the devices which the power industry needs. Factory Manager Gerald Kotte, 52, gives us the tour of the site and the factory facilities. Reconstructions are underway in every corner – the sign of global demand. Kotte explains how a transformer is put together – for laymen and in brief: “A transformer, like those we produce, comprises seven large assembly groups. The core with its laminated pressed steel frame, the windings with its winding frame and insulation parts, the tank and cooling system, open air leadthrough, the switch gears and finally the control and measuring instruments.” The boss then points out that transformers only run with alternating voltage, that a transformer takes around two months to produce – and that up to 40 000 (!) litres of coolant oil are required between the coils of each transformer.
And this is where HEROSE come into the picture: Since Siemens’ takeover of transformer company Koch & Sterzel (est. 1904) after the fall of the Berlin Wall, the fittings manufacturer from Bad Oldesloe has been one of the Dresden company’s regular suppliers. “We produce various valves and cocks for this customer”, says Volker Maass, Sales manager at HEROSE. Siemens has high quality demands. Factory Manager Kotte: “The fittings which we use have to be resistant to corrosion and temperature. It is also important that they are oil-tight and easy to operate and install. Our modern transformers have a service life of up to 50 years and have to work reliably in areas with extreme climatic conditions, therefore we also demand a high level of robustness.” There is no such thing as “off-the-peg” goods in the transformer business; every transformer is a special production. Why is the demand for Siemens products so high? Kotte: “Out transformers are known for their good quality and long service life, for effective cooling, low energy losses and low noise.”
Siemens’ “Power Transmission Division” operates 19 transformer factories in Europe, Asia and America from its head office in Nuremberg, and is the world’s second largest manufacturer, after ABB. The Dresden factory employees around 250 people. 50 percent of orders come from Germany, 40 percent from the Arab world. Gerald Kotte: “We have implemented a gigantic infrastructure there.” The graduate engineer forecasts a great future for his sector: “The demand for transformers will continue to increase.” But nobody will be resting on his laurels; research continues to be in demand, especially with regard to environmental protection: “Trials for cooling systems, for example, which aim to replace mineral oil with vegetable or synthetic esters, are currently being carried out”, says Kotte. “This is also important for all the offshore plants which will be installed in the North Sea and Baltic Sea over the next few years.”