Draft Details

Review start date:Dec 21, 2022
Review end date:Feb 19, 2023
Contact email:mary.morgan(at)csagroup.org
Draft Scope/Description:

1.1 General

This Standard specifies energy efficiencies for liquid-filled distribution transformers. The total ownership cost (TOC) methodology is recommended as the means for achieving these energy efficiencies, particularly for use by electric utilities. This Standard also specifies an optimal method for nonutility users, based on a modified TOC methodology that meets the conditions of energy cost.

1.2 Application

The transformers to which this Standard applies are single-phase and three-phase, 60 Hz, liquid-filled distribution transformers, rated at 10–833 kVA for single-phase and at 15–3000 kVA for three-phase, insulation class 34.5 kV and less, and low voltage windings of 600 volts or less.

1.3 Modification

This Standard describes special features that influence efficiency, and provides for the necessary modifications to the tabulated efficiency values.

1.4 Content

This Standard addresses the test methods and procedures for determining the transformer efficiencies.

1.5 Exclusions

This Standard does not apply to

a) Autotransformers;

b) testing transformers;

c) welding transformers;

d) furnace transformers;

e) rectifier transformers;,

f) network transformers;

g) grounding transformers;

h) a transformer with a nominal low-voltage winding line current of 4000 A or more at base kVA;

i) special impedance transformers;

j) transformers with special core/coil designs required by dimensional constraints;

k) transformers with tap ranges greater than 20%;

l) transformers with frequencies other than 60 Hz; or

m) step-voltage regulators.

1.6 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 (nonmandatory) to define their application.

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