This International Standard applies to outdoor and indoor bushings of any voltage used on DC systems@ of capacitance graded or gas insulated types for use as components of oil-filled converter transformers and smoothing reactors@ as well as air-to-air DC bushings. This standard 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) external to 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 the special terms used@ operating conditions@ ratings@ test procedures as well as general mechanical and electrical requirements for bushings for DC application.