Partial discharge weak spots localization in the stator insulation of running turbo generators

One of the best symptoms for the presence of defects in the HV insulation system is the detection of partial discharges (PD). Weak spots may be found by evaluating the PD repetition rate over the entire insulation system. If a severe degradation system is active, it will show a much higher PD repetition rate compared to the non-affected part of the insulation system. A method is introduced, which uses the propagation of the pulses through the stator core to localize partial discharges. With the knowledge of the exact spot at which each PD occurs it is possible to determine the PD repetition rate of PD occurrences in the entire stator. Weak spot localization can then be readily identified and localized by their enhanced repetition rate.