CSA C802.2-12 pdf download – Minimum efficiency values for dry-type transformers.
1 Scope 1.1 This Standard specifies efficiency values for dry-type transformers. The total ownership cost (TOC) methodology is recommended as the means for achieving these efficiencies, particularly for electric utilities. This Standard also specifies an optimal method for users other than utilities, based on a modified TOC methodology that meets the conditions of energy cost. Note: See Table 1 for minimum efficiency values. 1.2 This Standard covers single-phase and three-phase self-contained units or components of larger assemblies, 60 Hz, ANN, rated 15 to 833 kVA for single phase and 15 to 7500 kVA for three phase. 1.3 This Standard describes the special features that influence efficiency and provides modifications to the efficiency values specified in Table 1 where such modifications are necessary. 1.4 This Standard specifies the test methods and procedures for determining transformer efficiencies. D 1.5 This Standard does not apply to (a) autotransformers; (b) grounding transformers; (c) rectifier transformers; (d) sealed transformers; (e) nonventilated transformers; (f) testing transformers; (g) furnace transformers; (h) welding transformers; (i) encapsulated transformers; (j) drive (isolation) transformers with two or more output windings or a rated low-voltage line current greater than 1500 A; (k) transformers operating at a nominal frequency other than 60 Hz; (l) special impedance transformers; (m) transformers with a nominal low-voltage line current of 4000 A or more; (n) on-load regulating transformers; (o) resistance grounding transformers; (p) transformer with two or more independent windings for more than one independent output voltage; and (q) transformers with a low-voltage winding BIL above 30 kV.
1.6 In CSA standards, “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. 2 Reference publications This Standard refers to the following publications, and where such reference is made, it shall be to the edition listed below, including all amendments published thereto. CSA (Canadian Standards Association) C9-02 (R2011) Dry-type transformers CEATI International (Centre for Energy Advancement through Technological Innovation) D 456 A (1993) Economic Loading of Distribution Transformers NEMA (National Electrical Manufacturers Association) TP 2- 2005 Standard Test Method for Measuring the Energy Consumption of Distribution Transformers
3 Definitions The following definitions shall apply in this Standard: ANN (air cooled, natural convection, natural circulation of outside air) — dry-type natural cooling. Authority having jurisdiction — the governmental body responsible for the enforcement of any part of this Standard or the official or agency designated by that body to exercise such a function. Autotransformer — a transformer that has (a) one physical winding that consists of a series winding part and a common winding part; (b) no isolation between its primary and secondary circuits; and (c) during step-down operation, (i) a primary voltage that is equal to the total of the series and common winding voltages; and (ii) a secondary voltage that is equal to the common winding voltage. BIL — the basic impulse insulation level, indicating the ability of the transformer to withstand high-voltage surges. Cost of load loss — the present value of load loss, or load loss multiplied by the coefficient of load loss as employed in a loss evaluation formula. Note: The coefficient may also be described as the equivalent first-cost factor of load loss.CSA C802.2-12 pdf download.
