The Detection of Partial Discharges in High Voltage Potential Transformers in Service

This paper describes a test technique which has been developed for use in the field to detect internal partial discharges which may occur in high voltage potential transformers. The first stage consists of. detecting ultrasonic signals caused by the discharges. This is done while the equipment is still energized by the system. The second stage consists of removinj from service the transformers found to be producing high ultrasonic signal levels and then subjecting those transformers to tests to measure the partial discharge level.