STATOR COOLING ANALYSIS OF LARGE TURBO GENERATORS

The present paper deals with an investigation of flow parameters and thermalcharacteristics of the stator of large air-cooled turbo-generators. As the first step to modelthe complex geometry of the stator cooling system, the flow part is analyzed by specifyinguniform nodes along the airgap of stator. Flow resistances which are due to friction andminor losses are calculated and then pressure drops and flowrates are defined. For thethermal analysis, flowrates are employed and thermal network method is applied byconsidering nodes along stator windings and core in radial direction. Thermal resistancesand electro-mechanical losses are calculated and consequently by employing iterativesolution, temperature distribution at windings and stator core is obtained. Results reportedthat the maximum temperature is at windings where losses due to electric current exist.Furthermore, the stator core temperature decreases in radial direction. Also, based on thepredicted temperature rise of stator windings, the insulation class of stator windings isspecified. This necessitates the need for further optimizing the insulation materials. Resultsare in good agreement with available experimental data.

Keywords:

Stator , Turbogenerator , thermal Cooling , Thermal Network Method