A new approach in PD risk assessment based on AC and Lightning Breakdown Voltage prediction

Abstract:
Since many years, Partial Discharge (PD) measurements are a standard method to determine insulation integrity. For new equipment, the partial discharge level should be below a certain standardized level to be commissioned successfully. If a monitoring system detects partial discharges during operation of an electrical equipment, a risk assessment is necessary. Unfortunately, the discharge magnitude is not directly proportional to the remaining lifetime or the breakdown risk or breakdown voltage. Expert system or experienced professionals can identify the PD defect root cause with a good certainty. This helps to determine the given risk. Nevertheless, a clear risk quantification is missing. In this paper, a new approach is presented to predict the AC and lightning breakdown voltage of an equipment based on patterns from PD measurements. The method is validated with PD test data of several tip – plate configurations in air. A Neuronal Network is trained with these measurements. For control measurements with a different tip, it can be shown that the breakdown voltage can be predicted with an average failure of 5.3% for AC and 9.1% for lightning.