• 02 July 2018
• Admin
• 24

Insulator Pins, Called Ceramic Spacers, Are Attachet On The Collector To Keep A Constant Interelectrode Gap.

Cap and pin insulators of porcelain or glass predominate as overhead line suspension or tension sets above 33 kV and they are also used for substation busbar high level strained connections. Almost any creepage distance may be achieved by arranging the required number of individual units in a string. Upper surface shed shapes are similar with the top surface having a smooth hard surface to prevent the accumulation of dirt and moisture and a slope greater than 5° to assist self-cleaning. The undersides have a considerable variation in shape which depends upon aerodynamic and creepage distance requirements. illustrates standard, anti-fog and aerofoil disc profiles. Suspension insulator sets are rarely used in substation designs and substation busbar tension sets avoid the use of the anti-fog profiles because the deep ribs may not be naturally cleaned by rainfall when mounted nearly horizontally with short spans. Such substation short span applications do not require high strength cap and pin units and the insulators are often specified with 80 kN minimum failing electromechanical failing test load to meet a 3×safety factor requirement. Overhead line cap and pin insulators are specified with correspondingly higher failing loads of 125 and 190 kN.