Dry-type transformers

Energy Efficiency Regulations

Regulatory definition

Dry-type transformer, including one that is incorporated into any other product, in which the core and windings are in a gaseous or dry compound insulating medium and that:

• is either single phase with a nominal power of 15 to 833 kVA, or three-phase with a nominal power of 15 to 7500 kVA
• has a nominal frequency of 60 Hz, and
• has high voltage winding of 35 kV or less

but does not include:

• an auto transformer
• a drive (isolation) transformers with two or more output windings or a nominal low-voltage line current greater than 1500 A
• a grounding transformer
• a rectifier transformer
• a sealed transformer
• a non-ventilated transformer
• a testing transformer
• a furnace transformer
• a welding transformer
• a special impedance transformer*
• a transformers with a nominal low-voltage line current of 4000 A or more
• an on-load regulating transformer, or
• a resistance grounding transformer

Encapsulated transformers are considered a subset of non-ventilated transformers.

* Special impedance transformer means any dry-type transformer built to operate at impedance outside of the normal range for that transformer's nominal power in kVA as shown in the table of normal impedance ranges below:

Table of dry-type transformer normal impedance ranges

Single-phase		Three-phase
kVA	Normal impedance range (%)	kVA	Normal impedance range (%)
15	1.5 - 10.0	15	1.5 - 10.0
25	1.5 - 10.0	30	1.5 - 10.0
37.5	1.5 - 10.0	45	1.5 - 10.0
50	1.5 - 10.0	75	1.5 - 10.0
100	2.0 - 10.0	150	1.5 - 10.0
167	2.5 - 10.0	225	2.5 - 10.0
250	3.5 - 10.0	300	2.5 - 10.0
333	3.5 - 10.0	500	3.5 - 10.0
500	3.5 - 11.0	750	3.5 - 11.0
667	3.5 - 11.0	1 000	3.5 - 11.0
833	3.5 - 11.0	1 500	3.5 - 11.0
		2 000	3.5 - 12.0
		2 500	3.5 - 12.0
		3 000	4.5 - 12.0
		3 750	5.0 - 13.0
		5 000	5.0 - 13.0
		7 500	5.0 - 13.0

kVA = kilovolt-ampere

Compliance date

Manufactured on or after January 1, 2016

For models manufactured prior, refer to the Regulations

Compliant product models

Dry-type transformers as listed on NRCan’s searchable database

Testing standard

10 C.F.R. Appendix A - Appendix A to Subpart K, Part 431 of Title 10 to the United States Code of Federal Regulations, Uniform Test Method for Measuring the Energy Consumption of Distribution Transformers

Energy efficiency standard

Energy performance standard for dry-type transformers

	Percentage efficiency at 35% nominal load	Percentage efficiency at 50% nominal load
Single-phase kVA rating	1.2 kV Class	20-45 kV BIL	> 45-95 kV BIL	> 95-199 kV BIL
15	97.70	98.10	97.86	97.60
25	98.00	98.33	98.12	97.90
37.5	98.20	98.49	98.30	98.10
50	98.30	98.60	98.42	98.20
75	98.50	98.73	98.57	98.53
100	98.60	98.82	98.67	98.63
167	98.70	98.96	98.83	98.80
250	98.80	99.07	98.95	98.91
333	98.90	99.14	99.03	98.99
500	-	99.22	99.12	99.09
667	-	99.27	99.18	99.15
833	-	99.31	99.23	99.20
Three-phase kVA rating	1.2 kV Class	20-45 kV BIL	> 45-95 kV BIL	> 95-199 kV BIL
15	97.89	97.50	97.18	96.80
30	98.23	97.90	97.63	97.30
45	98.40	98.10	97.86	97.60
75	98.60	98.33	98.13	97.90
112.5	98.74	98.52	98.36	98.10
150	98.83	98.65	98.51	98.20
225	98.94	98.82	98.69	98.57
300	99.02	98.93	98.81	98.69
500	99.14	99.09	98.99	98.89
750	99.23	99.21	99.12	99.02
1 000	99.28	99.28	99.20	99.11
1 500	-	99.37	99.30	99.21
2 000	-	99.43	99.36	99.28
2 500	-	99.47	99.41	99.33
3 000	-	99.47	99.41	99.33
3 750	-	99.47	99.41	99.33
5 000	-	99.47	99.41	99.33
7 500	-	99.48	99.41	99.39

Note:

• BIL means basic impulse insulation level
• If the kilovolt-ampere (kVA) rating of the product falls between the kVA ratings set out in the table above, its minimum energy efficiency standard is an interpolation of the corresponding minimum efficiency standards specified for those ratings.
• For a three-phase transformer having multiple high-voltage windings and a voltage ratio other then 2:1, the minimum energy efficiency standard from the table or interpolated is reduced by 0.11.

Energy efficiency report requirements

• name of product
• brand name
• model number
• manufacturer
• name of the certification body or province whose verification mark will be on the product or its package
• whether a mathematical model as defined in the Regulations was used to generate any of the information provided below
• kVA rating
• single or three-phase
• low voltage winding in volts
• high voltage winding rating in volts
• whether it is 1.2 kV class
• BIL rating
• tested efficiency in per cent
• the loss, in watts, when under load (load loss)
• the loss, in watts, when not under load (no-load loss)
• whether it is three-phase with high-voltage windings and a voltage ratio that, between the highest and lowest of their nominal (rated) voltages, is other than 2:1
• percentage impedance

Download the energy efficiency reporting template.

This document does not constitute part of the Energy Efficiency Act (Act) or its associated regulations. This document is an administrative document that is intended to facilitate compliance by the regulated party with the Act and its associated regulations. This document is not intended to provide legal advice regarding the interpretation of the Act or its associated regulations. If a regulated party has questions about their legal obligations or responsibilities under the Act or its associated regulations, they should seek the advice of legal counsel.