Partial Discharge Measurement to Predict the Lifetime of High Frequency High Voltage Transformers

High Frequency/High Voltage Pulsed (HF/HVP) transformers are often used in low power applications. The insulation system is the most critical part of the design because the limited dimensions lead to the presence of high electrical stresses, furthermore the characteristics of the high voltage winding and of the high voltage pulses, result in a not uniform voltage distribution along the winding itself. The high electrical field concentrations require high performance insulating systems including enamels, filled polymers, loaded cast resins. The aim of this work is to implement a tool to be used during the manufacturing process to evaluate the quality of the insulating system as regards the expected lifetime. This tool, based on the partial discharge measurements, should be able to discriminate among HF/HVP transformers having expected lifetimes longer or shorter than a predefined value.