PD signatures of wedge type discharges in transformer insulation

G. Berg1, L.E. Lundgaard1
1SINTEF Energy Research, Norway

Tóm tắt

Discharge signatures have been studied in a combined transformer oil/impregnated paper insulation system subjected to AC high voltage. A semi-homogeneous sphere-plane electrode configuration was used to simulate wedge discharges in a power transformer. The moisture level of the impregnated paper was varied between 0.3% and 9.6%. At the highest moisture level no discharges were observed before breakdown. Below a threshold near 100 pC the discharges were almost harmless to the insulation. The variation of statistical parameters with experimental conditions was thoroughly investigated. It was found that the statistical moments skewness and kurtosis were very unstable and consequently not suitable for automatic pattern recognition.

Từ khóa

#Power transformer insulation #Partial discharges #Power transformers #Oil insulation #Petroleum #Electrodes #Moisture #Testing #Power measurement #Geometry

Tài liệu tham khảo

10.1109/ICDL.1999.798890 fruth, 1990, Partial discharge pattern recognition. A tool for diagnoses and monitoring of ageing, Cigré report 15/33–12 Paris gulski, 1991, Computer-Aided Recognition of Partial Discharges using Statistical Tools lundgaard, 0, Discharges in point-plane gap under ac and impulse stresses lundgaard, 0, Partial discharges in transformer insulation, Cigré main session paper 15–302