Investigation of Interface Between Various Overhead Distribution Insulator Types and 11kV Overhead Conductors

Student: Mark Stuart Appleton

Supervisor: Dr. Tapan Saha

Category: Electrical Engineering Thesis Project

This thesis details the testing of different insulator configurations for use with 11kV Covered Conductor Thick distribution lines. An energy distribution company in South East Queensland called Energex are interested in implementing covered conductors as a means to reducing the number of vegetation and wildlife related outages. The insulators investigated were the Pin Post, Clamp Top and the Tie Top. This work also attempted to determine the impact and usefulness of stripping the conductor near the attachment of the insulators. As partial discharges are proportional to the surrounding electric field, the field was modeled by finite element analysis and measured in the laboratory. The leakage current of each configuration was measured, as this can be detrimental to the insulating covering.

It was found that the Covered Conductor Thick passed the Australian Standards for partial discharges and even performed better than the stripped conductor in most cases. The partial discharges detected within the conductor were of the same magnitude as the background noise and were thus so small that it seems superfluous to strip at 11kV, though at increased operating voltages the discharges may be larger and it may then become necessary. When the conductor and insulators were modeled the stripped conductor always had a smaller electric field present than the covered conductor did. This was supported by the laboratory measurements that also showed that the pin post insulator had the greatest electric field for all samples of conductor.

Poster Presentation (PDF)

Thesis Document (PDF)