Medium power transformers

Measuring and improving energy efficiency

Energy performance of medium power transformers - IEC 60076-20

by IEC Advisory Committee on Energy Efficiency (ACEE)

While power transformers are generally very efficient, further improvements can yield additional substantial energy savings, taking into account their typical service life of 30 years or even more. For this reason the promotion of high-efficiency transformers is supported by policy instruments and programmes such as:

Minimum energy performance standards (MEPS)
Voluntary or mandatory product labeling
Financial incentives, subsidies and tax breaks
Support for R&D and demonstration projects

Currently, policy makers use a multitude of performance metrics in various country-specific programmes. While some programmes refer to the IEC 60076 series for rating transformers, there are programmes that continue to make reference to different rating standards and terminology.

The following table provides an overview of some of the relevant energy efficiency programmes for medium power transformers:

Country or region	Rated freq.	Ref.	Energy performance index	MEPS obligation and remarks
Australia and New Zealand	50 Hz	IEC	Efficiency for 50% load	Mandatory MEPS
Brazil	60 Hz	IEC	Losses for 50% load	Draft MEPS for dry type
Canada	60 Hz	IEEE	Efficiency for 50% load	Mandatory MEPS for dry type, Voluntary for liquid filled
China	50 Hz	IEC	Losses for 100% load	Mandatory MEPS
European Union	50 Hz	IEC	SR3150 kVA: Losses for 100% load, SR ≥ 3150 kVA: PEI	Mandatory MEPS
India	50 Hz	IEC	Losses for 100% load and for 50% load	Mandatory MEPS and labelling scheme for certain liquid immersed
Israel	50 Hz	IEC	Losses for 100% load	Mandatory MEPS
Israel	50 Hz	IEC	Losses for 100% load	Mandatory MEPS
Japan	50-60 Hz	IEC	SR ≤ 500 kVA: Total loss for 40% load, SR > 500 kVA: Total loss for 50% load	Mandatory labelling
Korea	60 Hz	IEC	Efficiency for 50% load	Mandatory MEPS
Mexico	60 Hz	IEEE	Efficiency for 100% load	Mandatory for liquid filled
USA	60 Hz	IEEE	Efficiency for 50% load	Mandatory MEPS and labelling
Vietnam	50 Hz	IEC	Efficiency for 50% load	Mandatory MEPS

The transformer energy performance calculated by using various minimum energy performance standards (MEPS) cannot always be compared because of the differences in rating conditions. IEC 60076 part 20 developed by IEC/TC 14 contains essential definitions that can be adopted by regional MEPS.