Experiences in Identification of Partial Discharge Patterns in Large Hydrogenerators

Some researchers´ experience of CVG EDELCA, in the identification of patterns of partial discharges (PD) in the large capacity hydroelectric generators of the Hydroelectric Power Stations Guri, Macagua and Caruachi of Venezuela are shown. For patterns identification of PD visual inspections, measurements of on-line and off-line partial discharges, measurements of acoustic vibrations in the core and frame of stator and register of concentration of ozone were carried out. Along with these results, some recognition of patterns in the Laboratory of Electromagnetic Rehearsals of Generation (LEMM) of the CIAP was carried out. As the slot discharges are directly related to the mechanical play of the bars of coil inside the slot, simulations in finite elements method (FEM) were performed to evaluate and determine the action of the electromagnetic forces of 120 Hz on the bars of the winding inside of the slots of the stator for different load conditions