IEEE - ANSI C57.12.55
Transformers Used in Unit Installations, Including Unit SubstationsConformance Standard
|Publication Date:||1 January 1987|
(This Foreword is not part of Amencan National Standard C57.12.55-1987.)
The High Voltage Apparatus Coordinating Committee (HVACC) was established July 24, 1972 by the Electrical and Electronic Technical Advisory Board (now superseded by the Electrical and Electronic Standards Management Board) of the American National Standards Institute. The responsibility assigned to HVACC was to review and evaluate existing American National Standards and other related standards for the purpose of developing a "Draft Standard" for unit substations and to develop recommendations for (1) correlating requirements of these standards and (2) adding requirements to these standards appropriate for product evaluation.
This standard results from the evaluation of existing American National Standards and the need to add requirements to these standards for the evaluation and conformance certification of dry-type transformers. This document refers to the proposed revision of American National Standard for Dry-Type Transformers, ANSI/IEEE C57.12.01-1979 (now in preparation).
This document includes Appendixes A and B, outlining procedures recommended for qualifying insulation systems; related material is covered in American National Standard Test for Thermal Evaluation of Insulation Systems for Ventilated Dry-Type Power and Distribution Transformers, ANSI/IEEE C57.12.56-1984.
This standard is not intended to cover application, installation, or operation of dry-type transformers.
Transformers certified under this standard may contain accessories necessary for installation. For the conformance requirements for such accessories, reference should be made to the American National Standard for each specific accessory involved. Typical accessories of a pad-mounted installation are fuses, lightning arresters, circuit breakers, motor starter controls, and the like.
Suggestions for improvement of this standard will be welcome. They should be sent to the National Electrical Manufacturers Association, 2101 L Street, NW, Suite 300, Washington, DC 20037.
This standard describes certain electrical, mechanical, and safety requirements and conformance tests for dry-type distribution and power transformers and for autotransformers. These transformers may be either single-phase or polyphase, with ventilated, nonventilated, or scaled enclosures.
Such transformers may be remotely or integrally associated with primary or secondary switchgear or substations, or both. The range of transformers is 601 volts through 34 500 volts (either primary or secondary) in sizes of 1 kVA through 2 500 kVA. Such transformers are intended to be installed in accordance with the AmericanNational Standard National Electrical Code (ANSI/NFPA 70-1987). All manufacturers seeking certification under this standard should demonstrate that performance requirements have been met by perfoming the tests herein, by submitting data from earlier tests, by exhibiting proof of satisfactory field service, or by an appropriate combination of these methods. Families of insulation systems may be certified on the basis of tests performed on one representative model.