Critical review of commissioning/routine tests with special interest in undetected defects in SF6, GIS/GITL using UHF method
Date
2009-11-04T11:45:47Z
Authors
Cebekhulu, Jabulani
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Abstract
The widespread application of pressurized SF6 gas and its mixtures as
insulating medium in many electric power applications is the result of recent
advances in technologies. The likelihood of failure for a Gas Insulated
Substation or Transmission Line (GIS/GITL) is primarily due to the presence
of defects inside the equipment. Defects can be introduced into the GIS/GITL
system for various reasons. Partial discharge (PD) is a natural phenomenon
occurring in the GIS/GITL systems, which invariably contains defects. During
commissioning or routine tests PD measurements serve to identify the type
and status of a defect. Of particular interest for this research work will be the
critical review of PD measurement for different types of free conducting
particles in the gas using the UHF method due to its superiority among
others. The work highlights the integrity of the method as a tool for both
commissioning and routine tests and its alignment with the high voltage SF6
test standards is reviewed. 80/20 N2/SF6 mixture is used to reduce the surface
roughness effect in pure SF6, as well as for the reduction of economical and
environmental risks.
Description
Keywords
GIS/GITL, Inception voltage, Lift-off field, Partial discharge, UHF PD testing