Use of a medical ultrasonic scanner for the inspection of high voltage insulation

It is shown that standard medical ultrasound scanners can provide rapid inspection of insulating materials, detecting possible areas of field-induced degradation. The position and the extent of degradation within the material can be given. This work was performed on practical insulating structures and on pieces fabricated in the laboratory. The samples contain defects that simulate conditions that can occur in production processes and during the in-service life of insulation. The results are affected by fillers and by the structure of the material. Excellent results were obtained from cast polyurethane and epoxy resins containing the usual particular fillers in the usual proportions.<>