Development and Validation of Estimation of Breakdown Voltage of Stator Windings of Generator From Partial Discharge Magnitude

For the insulation diagnosis of stator windings of generators, sampling surveys are conducted on the coils to estimate the dielectric strength of the stator winding. Previous research has relied on inferring the breakdown voltage of the stator winding from the value 3σ away from the mean value of the breakdown voltage of the coil. However, this conventional method exhibits a significant estimation error when the sample size is small. Therefore, we propose a method for estimating the breakdown voltage of the stator winding based on the maximum value of the partial discharge magnitude and the minimum value of the breakdown voltage of the sample coil. We verify this method by Monte Carlo simulation assuming a sampling survey of coils.