New results in the search for electrical signals during water tree growth

Polyethylene samples, printed in one region with needles to greatly accelerate water treeing, were exposed to high voltage (60 Hz AC and DC) and a water treeing solution. A very-low-noise, wide-bandwidth detection system was developed to monitor signals occurring in the sample via two probes located under the sample, one at a reference region and the other at the treeing region. Two distinct signals have been found that originate only in the active needle printed region. It has not been determined conclusively however, that the detected signals are due to water treeing, just that they originate at the water treeing site