Pre-Breakdown Condition of Insulation Recognition by Partial Discharges Characteristics

The partial discharge method is promising for preventing accidents at intelligent power supply systems. Based on the characteristics of partial discharges, it is possible to determine the pre-breakdown situation of solid, inter-turn and liquid insulation of power transformers, high-voltage cables, motors, and other elements of stations and substations. The article presents comparative results of the analysis of partial discharge characteristics obtained in the laboratory using a telescopic antenna at constant and alternating applied voltage. It is shown how, using a specially modified telescopic antenna with improved characteristics, it is possible to recognize situations far from breakdown in the initial stage of breakdown and immediately before breakdown of the air discharge gap by the characteristics of partial discharges. Part of the work is devoted to determining the polarity of partial discharges, which is important for localizing their source and type of defects. A telescopic antenna was used for partial discharges registration.