This International Standard is applicable to polymeric insulators for a.c. systems with a nominal voltage greater than 1 000 V (frequency less than 100 Hz) and d.c. systems with a nominal voltage greater than 1 500 V whose insulating body consists of one or various organic materials.
Polymeric insulators covered by this standard are intended for use both on HV overhead lines and in substations, in both indoor and outdoor applications. They include composite insulators with solid and hollow core and resin insulators. Hybrid insulators with ceramic core and polymeric housing are also included, while coated insulators (e.g. with RTV silicone rubber coatings) are not included in this standard. Electrical tests described in this standard are done under a.c. voltage and are in general applicable to insulators to be used in d.c. systems too.
Tests under d.c. voltage should reflect up-to-date knowledge and experience..
The object of this standard is
- to define the common terms used for polymeric insulators;
- to prescribe common test methods for design tests on polymeric insulators;
- to prescribe acceptance or failure criteria, if applicable;
These tests, criteria and recommendations are intended to ensure a satisfactory lifetime under normal operating and environmental conditions (see Clause 5). The standard includes design tests intended to reject materials or designs which are inadequate under normal operating and environmental conditions. This standard shall only be applied in conjunction with the relevant product standard.