University of Manchester

Observation of electrical trees in non-filled and nano-filled polymeric high voltage insulation

Takahiro Nakamura
Project Completed

Scientific Case

Electrical treeing is one of the main reasons for the failure of polymeric high voltage insulation. Electrical trees originate from defects such as metal particles and voids, which leads to ultimate breakdown of the insulation. Mechanisms of electrical treeing have not yet been resolved due to the difficulty in obtaining the structure and composition of a tree. Recently nano-particles embedded within epoxies, known as nano-filled epoxies, have received a lot of attention due to their high voltage endurance. In previous research, trees in nano-filled samples have been found to grow more slowly than in a non-filled samples. In this experiment, the structure of trees in non-filled and nano-filled samples will be observed. The results of this study is expected to contribute towards understanding the effect of nano-fillers on the breakdown mechanism and may also shed some light on the mechanism itself.

Experiment Design

Sample size: Cylinder whose diameter is 3mm
FOV:1mm to 3mm *1mm
Pixel resolution: less than 1.5μm
Scanners and Rigs
Xradia VersaXCT
Not Required
Require 40x optics (currently on DCT Versa)

Sample & Safety

Cylindrical epoxy whose diameter is 3mm.
Needle whose diameter is 1mm is inserted to epoxy.
Height of epoxy is 13mm, and total height of sample with needle is 63mm.
Low Hazard

Scan Records

Project Report