Impulse voltage breakdown properties of electrodes with thick dielectric coatings in SF6
Document type:
Konferenzbeitrag
Contribution type:
Textbeitrag / Aufsatz
Author(s):
Marold, J.; Kindersberger, J.
Chapter contribution:
T9-75
Abstract:
For improving the electrical strength of gas
insulated switchgears (GIS) dielectric coatings can be
used. While thin coatings (< 1 mm) are covering the
rough surface by a smooth dielectric layer, coatings
with a thickness of several millimetres may change the
macroscopic electric field distribution significantly. For
electrode arrangements with inhomogeneous field
distribution the maximal electric field in the gas gap can
be reduced by applying thick dielectric coatings. Thus
streamer inception occurs at higher applied voltages and
the breakdown voltage increases.
The performance of thick dielectric coatings is
investigated theoretically and experimentally. The
theoretically possible improvement was calculated
depending on electrode geometry (field utilization factor
0.25 to 0.53), the relative permittivity εr (2 to 5) and the
thickness of the coating (3 to 20 mm). The experimental
setup consists of a rod-plane electrode arrangement with
different rod diameters (4 and 30 mm), coating
materials (Al2O3-filled epoxy resin and polyethylene)
and coating thicknesses (3and 8 mm). As insulation gas
SF6 at 0.4 MPa was used.
Book / Congress title:
XV. International Symposium on High Voltage Engineering
Congress (additional information):
Ljubljana, Slovenia, August 27-31, 2007
Organization:
University of Ljubljana, Elektroinštitut Milan Vidmar