2. Partial Discharges: Physics and Classification

Partial discharges (PDs) are electric discharges that occur in electrical insulation systems, indicating potential insulation failure. This chapter delves into the physics of PDs, explaining how ionization of insulator materials leads to these discharges. It classifies PDs into surface and internal discharges, and discusses various types of PDs, such as corona, slot discharges, and surface tracking. The chapter highlights the importance of detecting PDs early to prevent insulation degradation and equipment failure. It also covers different measurement techniques, including capacitive coupling and phase-resolved partial discharge (PRPD) analysis. Additionally, it explores the characteristics of PDs, such as frequency, amplitude, and phase, and their significance in assessing insulation condition. The chapter emphasizes the need for accurate detection and monitoring of PDs to ensure the safety and reliability of electrical systems.