Report Compiled on New Energy Efficiency Standards for Transformers (For building and factory)

1. Outline

As Japan places more importance on the improvement of energy efficiency of products through thorough energy conservation to achieve a goal of carbon neutrality by 2050, the working group on energy efficiency standards^(*3) under ANRE held meetings from September 2022 to discuss new energy efficiency standards for transformers (for building and factory) in accordance with the Top Runner Program under the Act on Rationalizing Energy Use and Shifting to Non-fossil Energy.^(*4) As an outcome of the discussions, on June 15, 2023, the working group compiled the Report on the New Energy Efficiency Standards for transformers (for building and factory)^(*5) after it held a meeting on May 30, 2023.

The report sets the target equipment, target fiscal year, categories, target standard values and other values related to the transformers (for building and factory) that are subject to the standards, and also shows estimated improvement rates in energy efficiency in the target year, providing an estimation of the level of improvement that likely will be achieved.

2. Improvement rates of energy efficiency in the target fiscal year

The energy efficiency of transformers (for building and factory) employs “total power loss” in a power transformer as its index for measurement. In this context, the average total power loss of such transformers subject to the standards will be 444.1W per unit in FY2026, the target fiscal year. Meanwhile, the total power loss in such transformers in FY2019 was 501.1W per unit, meaning that the energy efficiency is estimated to improve by about 11.4% by FY2026.

3. Outline of the report

(1) Target transformers (for building and factory)

Transformers (for building and factory) whose rated primary voltage exceeds 600V but are not more than 7,000V and that are used in AC circuits.

(2) Target fiscal year

FY2026

(3) Categories

24 categories are set based on five factors, namely type, number of phases, rated frequency, rated capacity, and specification.

(4) Target standard values

The next target standard values for transformers (for building and factory) are shown in the following table.^(*6)

Category					Calculation formula of target standard values involving the energy efficiency standards
Type	Number of phases	Rated frequency	Rated capacity	Specification
Oil-filled	Single-phase	50Hz	Not more than 500kVA	Standard specification	Ｅ= 9.34・(kVA)0.737
Oil-filled	Single-phase	60Hz	Not more than 500kVA	Standard specification	Ｅ= 8.60・(kVA)0.744
Oil-filled	Three-phase	50Hz	Not more than 500kVA	Standard specification	Ｅ= 14.5・(kVA)0.694
Oil-filled	Three-phase	50Hz	Beyond 500kVA	Standard specification	Ｅ= 10.6・(kVA)0.797
Oil-filled	Three-phase	60Hz	Not more than 500kVA	Standard specification	Ｅ= 14.4・(kVA)0.681
Oil-filled	Three-phase	60Hz	Beyond 500kVA	Standard specification	Ｅ= 8.00・(kVA)0.825
Mold	Single-phase	50Hz	Not more than 500kVA	Standard specification	Ｅ= 14.1・(kVA)0.685
Mold	Single-phase	60Hz	Not more than 500kVA	Standard specification	Ｅ= 13.3・(kVA)0.692
Mold	Three-phase	50Hz	Not more than 500kVA	Standard specification	Ｅ= 16.9・(kVA)0.699
Mold	Three-phase	50Hz	Beyond 500kVA	Standard specification	Ｅ= 31.2・(kVA)0.659
Mold	Three-phase	60Hz	Not more than 500kVA	Standard specification	Ｅ= 16.2・(kVA)0.702
Mold	Three-phase	60Hz	Beyond 500kVA	Standard specification	Ｅ= 17.4・(kVA)0.742
Oil-filled	Single-phase	50Hz	Not more than 500kVA	Semi-standard specification	Ｅ=（9.34・(kVA)0.737)・1.10
Oil-filled	Single-phase	60Hz	Not more than 500kVA	Semi-standard specification	Ｅ=（8.60・(kVA)0.744）・1.10
Oil-filled	Three-phase	50Hz	Not more than 500kVA	Semi-standard specification	Ｅ=（14.5・(kVA)0.694）・1.10
Oil-filled	Three-phase	50Hz	Beyond 500kVA	Semi-standard specification	Ｅ=（10.6・(kVA)0.797）・1.10
Oil-filled	Three-phase	60Hz	Not more than 500kVA	Semi-standard specification	Ｅ=（14.4・(kVA)0.681）・1.10
Oil-filled	Three-phase	60Hz	Beyond 500kVA	Semi-standard specification	Ｅ=（8.00・(kVA)0.825）・1.10
Mold	Single-phase	50Hz	Not more than 500kVA	Semi-standard specification	Ｅ=（14.1・(kVA)0.685）・1.05
Mold	Single-phase	60Hz	Not more than 500kVA	Semi-standard specification	Ｅ=（13.3・(kVA)0.692）・1.05
Mold	Three-phase	50Hz	Not more than 500kVA	Semi-standard specification	Ｅ=（16.9・(kVA)0.699）・1.05
Mold	Three-phase	50Hz	Beyond 500kVA	Semi-standard specification	Ｅ=（31.2・(kVA)0.659）・1.05
Mold	Three-phase	60Hz	Not more than 500kVA	Semi-standard specification	Ｅ=（16.2・(kVA)0.702）・1.05
Mold	Three-phase	60Hz	Beyond 500kVA	Semi-standard specification	Ｅ=（17.4・(kVA)0.742）・1.05

(5) Improvement rates of energy efficiency in the target fiscal year

The new standard values in the target fiscal year (FY2026) are estimated to improve by about 11.4% from the actual values in the reference fiscal year (FY 2019) on the assumption that the composition by category and by rated capacity of FY2026 shipments will be the same as those of the FY2019 actual shipments.

*Notes:

1. The new standards are expressed not in a specific numeral target but in a mathematical formula.
2. The target equipment is limited to power transformers with the standard specification.
3. Working Group on Classification Standards for Transformers of the Energy Efficiency and Conservation Subcommittee of the Committee on Energy Efficiency and Renewable Energy under the Advisory Committee for Natural Resources and Energy
4. Act on Rationalizing Energy Use and Shifting to Non-fossil Energy
5. Report on Transformers (for building and factory) compiled by the Working Group on Classification Standards for Transformers of the Energy Efficiency and Conservation Subcommittee of the Committee on Energy Efficiency and Renewable Energy under the Advisory Committee for Natural Resources and Energy
6. E: Energy efficiency standards for transformers (unit: W)

Division in Charge

Energy Efficiency Division, Energy Efficiency and Renewable Energy Department, Agency for Natural Resources and Energy