Study Regarding the Level of a Hydrogenerator Partial Discharges

In order to ensure electricity requirements, it is necessary that there are no interruptions in the operation of power plants, caused by various defects. For this purpose, a permanent monitoring of the sizes and operating parameters of the aggregates is necessary. Determining the condition of the insulation is an important characteristic in the proper operation of electrical generators. In order to determine the insulation condition of the stator winding of a hydrogenerator, measurements were accomplished in order to determine the level of partial discharges when the generator is operating at idle state and loaded. From the analysis of the variation of the level of partial discharges as a function of voltage and power, it appears that the windings of the tested generator are so far adequate in terms of insulation. However, attention should be paid to the winding on phase A, where no linear variations were found. At the same time, the windings temperature and the operating regime influence the value of the partial discharges. In order to prevent the failure of the generators determined by the degradation of the windings insulation over time, it is necessary to carry out periodically specific measurements.