Ceramic/Porcelain suspension disc
insulators are widely used in power systems to provide
electrical insulation and mechanically support for
high-voltage transmission lines. These insulators are
subjected to a variety of stresses, including mechanical,
electrical and environmental. These stresses act in
unison. The exact nature and magnitude of these stresses
vary significantly and depends on insulator design,
application and its location. Due to various reasons the
insulator disc can lose its electrical insulation properties
without any noticeable mechanical failure. Such a
condition while difficult to recognize, can enhance the
stress on remaining healthy insulator discs in the string
further may lead to a flashover. To understand the stress
enhancement due to faulty discs in a string, attempt has
been made to simulate the potential and electric field
profiles for various disc insulators presently used in the
country. The results of potential and electric filed stress
obtained for normal and strings with faulty insulator
discs are presented.