Power Station
Process | Generator
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The single-shaft generator is of two-pole type, with direct radial hydrogen cooling for the rotor winding and indirect hydrogen cooling for the stator winding. The hydrogen filled generator casing is a pressure-resistant and gas-tight construction and is equipped with end shields at each end. The three-phase winding inserted in the stator core slots is a two-layer transposed-bar design. The winding is vacuum pressure impregnated together with the stator core. The generator rotor shaft is a vacuum-cast forging and has two end-shield sleeve bearings. The hydrogen is circulated in the generator interior in a closed circuit by axial-flow fans arranged on the rotor shaft journals. A gas system contains all necessary equipment for filling, removal and operation of the generator with purging gas, hydrogen or air. An excitation transformer is used to take the excitation current from the auxiliary power system. A start-up frequency converter is provided for start-up of the turbine generator unit. The generator acts as a motor in the converter mode to start the gas turbine set without additional rotating prime mover. The converter forms part of the exciter unit. |
