للكاتب
E. A. Eisawy
Operational Safety Dept., National Center for nuclear safety
ABSTRACT
The paper presents an important simplification by introducing the surface resistivity to
classify and estimate the deterioration breakdown process. The results show that the
breakdown voltage increases with increasing surface resistivity of the insulator.
Several test methods have been developed to examine the performance of insulators in
a reactor’s electrical system. Factors which affect or influence surface resistivity on
insulators breakdown have been analyzed. The obtained values depend on a number
of factors, including temperature, applied voltage, humidity, moisture content,
electrification time and frequencies. Comparing or interpreting data is difficult unless
the test is controlled and defined, especially when a specimen is drying out after being
subjected to moist or humid conditions. The surface temperature at the breakdown
location has been measured and a good correlation with the decomposition
temperature of the insulators has been found. For electrode separations of 1mm or
greater the breakdown voltage does not increase linearly with the length of the
insulator. The breakdown voltage over an insulator is raised when the edge of the
insulator close to either electrode is rounded. Insulation deteriorations against time
and temperature changes which are important have been introduced. The breakdown
mechanisms of insulation operating under wet and dry conditions have been
discussed.
That's really thinknig out of the box. Thanks!