CSA C2.1:24

Preface This is the second edition of CSA C2.1, Single-phase and three-phase liquid-filled distribution transformers. It supersedes the previous edition published in 2006 and previous editions of CSA C2, Single-Phase and Three-Phase Liquid-filled Distribution Transformers, Types ONAN and LNAN, published in 1991, 1982, 1976, 1969, 1959, 1944, 1928, and 1920. This edition includes requirements for single-phase, single-bushing, 60 Hz distribution transformers suitable for direct pole mounting and designed for operation on an effectively grounded wye system, Type ONAN, rated at 167 kVA or below, up to 34.5 kV system nominal voltage. Changes to this edition include updates to various clauses, tables, figures, and annexes to reflect minimum industry requirements. This Standard specifies the requirements for distribution transformers intended primarily for operation by electric utilities. The operation of transformers complying with this Standard by other than an electric utility could be subject to additional requirements by the electrical inspection regulatory authority having jurisdiction. CSA Group acknowledges that the development of this Standard was made possible, in part, by the financial support of Alectra Utilities, Electricity Canada (EC), EPCOR, FortisAlberta, FortisBC, Hydro One, Hydro-Québec, IFD Corp., K-Line Insulators Ltd., Maritime Electric, NB Power, Newfoundland and Labrador Hydro, Newfoundland Power, Nova Scotia Power, S&C Electric Canada Ltd., Schneider Electric Canada Inc., Toronto Hydro, and Utilities StandardDetails Forum (USF). This Standard was prepared by the Subcommittee on Overhead and Pad-Mounted Distribution Transformers, under the jurisdiction of the Technical Committee on Distribution Transformers and the Strategic Steering Committee on Power Engineering and Electromagnetic Compatibility, and has been formally approved by the Technical Committee. This Standard has been developed in compliance with StandardDetails Council of Canada requirements for National StandardDetails of Canada. It has been published as a National Standard of Canada by CSA Group. Scope 1.1 Inclusions This Standard specifies the requirements for distribution transformers except for those distribution transformers covered by CSA C2.2, CSA C227.3, and CSA C227.4. Note: The operation of transformers complying with this Standard by other than an electric utility might be subject to additional requirements by the electrical inspection authority having jurisdiction. 1.2 Ratings This Standard applies to single- and three-phase, 60 Hz, liquid-filled distribution transformers rated at 1000 kVA or below for single-phase, and at 3000 kVA or below for three-phase, up to 34.5 kV system nominal voltage. 1.3 Performance characteristics This Standard includes voltage ratings, kVA ratings, certain mechanical characteristics, and test procedures. It also includes the following performance characteristics: energy efficiency (in accordance with CSA C802.1), temperature rise, loading capabilities, sound level, and radio influence voltage (RIV). 1.4 Self-protected transformers This Standard also applies to self-protected transformers with the exception of protective equipment. 1.5 Exceptions Except as specified by other CSA StandardDetails, this Standard does not apply to auto-, testing, dry-type, welding, furnace, rectifier, network, subway, or special-purpose transformers, or to step-voltage regulators. 1.6 Units of measurement The values given in SI units are the units of record for the purposes of this Standard. The values given in parentheses are for information and comparison only. 1.7 Terminology In this Standard, "shall" is used to express a requirement, i.e., a provision that the user is obliged to satisfy in order to comply with the Standard; "should" is used to express a recommendation or that which is advised but not required; and "may" is used to express an option or that which is permissible within the limits of the Standard. Notes accompanying clauses do not include requirements or alternative requirements; the purpose of a note accompanying a clause is to separate from the text explanatory or informative material. Notes to tables and figures are considered part of the table or figure and may be written as requirements. Annexes are designated normative (mandatory) or informative (non-mandatory) to define their application.