This International Standard applies to outdoor and indoor bushings of any voltage used on DCsystems, of capacitance graded or gas insulated types for use as components of oil-filledconverter transformers and smoothing reactors, as well as air-to-air DC bushings. Thisstandard does not apply to the following:• cable terminations (potheads);• bushings for instrument transformers;• bushings for test power supplies;• bushings applied with gaseous insulation (other than air at atmospheric pressure) externalto the bushing;• bushings for industrial application;• bushings for traction application;• bushings for distribution class transformers.This standard makes reference to IEC 60137 for general terms and conditions and defines thespecial terms used, operating conditions, ratings, test procedures as well as generalmechanical and electrical requirements for bushings for DC application.