Robust Fans Are In Demand

Power transformers are elementary components of electrical energy supply. They convert the AC voltage between different voltage levels and are therefore indispensable for power generation, transmission or distribution in power plants, industrial companies and substations. Power transformers are installed outdoors. Here they have to defy wind and weather as well as moisture in the rainforest, salt mist on the coast, scorching heat in desert areas or icy cold on the Arctic Circle. The fans used on the cooling systems must also play along. Robust technology that works reliably and maintenance-free for several years is in demand. Every transformer failure would have fatal consequences, since the energy supply would no longer be guaranteed.

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A lot of waste heat is generated during the operation of transformers, mostly oil is used as a coolant. It transfers the heat by convection - or supported by pump systems - to the transformer housing, which has cooling fins or radiator-like radiators on the outside. In the case of large power transformers, these are additionally cooled with fans in order to avoid damage due to overheating despite the most compact cooling surfaces possible. These fans have to meet special requirements so that they can withstand the harsh outdoor conditions.

Fans transform transformers into energy savers

So it is not enough if the fans promote the desired air output. Properties such as corrosion resistance even in high humidity, maintenance-free operation without lubrication and reliable function over the longest possible service life are just as important. It is also advantageous if the cooling capacity can be adapted to the actual demand in the event of load fluctuations. Because it often does not make sense to switch off individual fans completely when the transformer is under partial load, because in this area uncooled “hot spots” can then arise on the heat exchanger. If the fans also work as efficiently as possible, considerable amounts of energy and costs can be saved over the years, which in turn can be fed into electrical networks. This creates an economically positive benefit for the energy operator.If the transformers are in the vicinity or even within residential areas, the noise level also plays a role that should not be underestimated.

The motor and fan specialist EBM-Papst has taken on this topic and developed special transformer fans. They meet all the requirements for sophisticated large transformer cooling in accordance with DIN EN 50216-12 "Accessories for transformers and choke coils - Part 12: Fans" and are available in sizes 500 mm to 1250 mm with air flow rates of up to 13 m³ / s. Their development is based on decades of experience and intensive research work, supported by extensive simulations and tests. Special requirements with regard to long service life and resistance to salt spray (corrosion protection class C5M according to DIN EN ISO 12944) are met, so the fan is also suitable for use near the coast with high salt loads.

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Content of the article:

• Page 1: Robust fans are in demand
• Page 2: Wall ring increases fan efficiency
• Page 3: Part-load operation has several positive effects

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