Siemens will conduct development activities for local and regional markets increasingly on site. This is already the case to some extent at the company’s plant in Tenjo, Colombia, although the facility still relies on German expertise for its new motors.

Siemens has been building transformers in Colombia since 1956 – everything from small systems for power distribution to large high-performance units. Over the last two years, the Tenjo plant has been specialising in the production of distribution transformers for renewable-energy facilities.

“This market is growing rapidly, particu- larly in the US and Canada,” says head of transformer marketing Andrés Villate.

Siemens is building transformers in Colombia that are cooled with vegetable oil rather than industrial oil. As reported in the latest issue of the magazine, Pictures of the Future, the ‘vegetable oil transformers’ are safer and more environment friendly than conventional units and also require fewer safety systems for preventing fires and leaks.

Transformer components are normally cooled and insulated with petroleum or silicon oil. However, vegetable oil offers the benefit of complete biodegradability and it is also less flammable than mineral oils. The transformers from Colombia have been installed at North and South American solar and wind power facilities, besides other places.

Transformers are used at substations to either raise or lower alternating current voltage to enable electricity to be transported in high-voltage networks, for example. Their ‘job’ at wind and solar power facilities is to convert electrical energy into the right voltage for feeding into the grid. The extremely high currents and voltages the transformers are exposed to cause them to become very hot, which is why thousands of litres of oil are needed to cool them. Mineral and silicone oils have traditionally been used for this purpose, as both are good at channelling off heat and insulating against electrical flash- overs. These oils can be highly inflammable and bad for the environment, however.
The new insulating oil is made from rapeseed, soy, or sunflowers, which makes it bio- degradable. It also has a much higher flashpoint than industrial oils. Moreover, because it poses absolutely no danger to groundwater or rivers, it can be used in areas subject to strict environmental protection regulation.

Complex systems for protecting against oil leaks are no longer necessary with the plant-oil transformers, which can, therefore, be built at a lower cost.

Siemens Energy is currently using its vegetable oil solution in small transformers with a voltage of up to 69 kV and a power rating of 30 MA. Siemens has built more than 30 of the transformers to date.

Environment-friendly solutions for power distribution are part of the Siemens environmental portfolio, which generated about €30-billion in sales in fiscal 2011.

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