A 1.000 kW turbogenerator with a cooling temperature of 269 °C – close to absolute zero – has been made and tested in our country. In power engineering we have been building larger and larger capacity generators because they are more economical. We have 800.000 kW generators in serial production in our country; at the Elektrosila Association they are testing a 1.200.000 kW generator, and have even begun thinking about a 2.000.000 kW generator.
But you cannot go on increasing size indefinitely, for with size you must also increase structural strength, and eventually you reach a point when you simply cannot do it. Increasing the loading is no better, for this soon leads to overheating. That's where the cryogenic generator comes in. The steel rotor of a conventional turbo generator, which can weigh upwards of 100 tons, is replaced in the cryogenic generator by a revolving vessel of 770 mm diameter, at present the largest in the world, in which a coil of niobium-titanium alloy is mounted and kept at a temperature of – 269 °C by liquid helium.
In this cosmic cold, the windings acquire the amazing property of superconductivity – they have no resistance to current and so do not heat up, while generating a very large magnetic flux.
The efficiency can thus be raised to 99,3 per cent, and a unit capacity of more than 5 million kW may well be within our reach.
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