7. Quality standards1.The measurement of insulation resistance should comply with the following regulation: The resistance of suspension insulator which is used for voltage class of 330kV and below should not be lower than 300MΩ; The resistance of suspension insulator which is used for voltage class of 500kV and above should not be lower than 500MΩ; The resistance of post insulator which is used for voltage class of 35kV and below should not be lower than 500MΩ.2.AC voltage endurance test should comply with the following regulations: The post insulators which are used for voltage class of 35kV and below should take AC voltage endurance tests, which could be conducted together after the installation of busbar was completed. The test voltage should be in line with the stipulation in appendix F of testing regulation GB-50150, the test voltage value for the AC voltage endurance test of suspension insulator should be 60kV.