This guide is mainly applicable to throe-phase systems up to 525 kV (phase-to-phase). For higher voltages the possible non-linear performance of insulators is still under study.
This guide is applicable to outdoor ceramic and glass insulators, used in a.c. systems, of the following types:
— long-rod and traction line insulator ;
— cap and pin insulator;
— pedestal type post and rigid pin insulator;
— substation and line post insulator;
— hollow insulator;
— bushing.
This guide cannot directly be used for special types of insulators such as insulators with conductive glaze, or covered, during the manufacturing, with any insulating material, for surge arresters and also for longitudinal insulation for open circuit-breakers. This guide does not deal with radio interference voltage, television interference voltage and audible noise, the intensity of which may be increased on some polluted insulators.