Assessment of the stator-winding insulation state based on partial-discharge measurements

The paper proposes solving the issue of partial discharges occurring in the stator-winding insulation and possibilities for determination of the stator-winding state based on on-line partial-discharge measurements. The main advantage of the presented approach is, in contrast to the traditional methods, the possibility to locate the insulation damages based on the measurement results obtained during the machine on-duty state. Also, the results are more accurate, as the partialdischarge rate very much depends on the machine status (e.g. temperature, vibrations, load, etc.). A paper presents a measurement case carried on generator no. 3 of the Solkan hydropower plant.