This standard applies to indoor and outdoor AC high-voltage equipment and control equipment operating in power systems with a voltage of 3.0kV and above and a frequency of 50Hz. Unless otherwise specified in the product of high-voltage switchgear and control equipment, this standard applies to all high-voltage switchgear and control equipment. Anything beyond the requirements of this standard may be separately specified in the corresponding product standards.
GB 311.1-1997 Insulation co-ordination for high voltage transmission and distribution equipment
GB 772-1987 Technical specification of porcelain element for high voltage insulators
GB/T 311.2-2002 Insulation co-ordination Part 2: Application guide for insulation co-ordination for high voltage transmission and distribution equipment