Artificial rain test of outdoor long rod insulators

Due to the decrease of industrial contamination emission nearly the whole territory of Poland belongs to the pollution class light. As a result, the insulators can have now a very short leakage distance. The long-term tests carried out at Glogow test station show that cylindrical insulators without sheds and with a small diameter can have the specific leakage distance of 0,8 cm/kV which is twice shorter than that recommended by the international standard IEC60815. This is valid not only for silicone rubber insulators but even for porcelain insulators. To understand this surprisingly good performance, the test results of porcelain cylindrical insulators and standard long rod insulators under artificial rain were presented. The influence of water conductivity, shed parameter and inclination angle from the vertical line was also shown