Amorphous Transformer Contributing to Global Environmental Protection
250
Amorphous Transformer Contributing to Global
Environmental Protection
Katsutoshi Inagaki
Masanao Kuwabara
Kohei Sato
Kazuyuki Fukui
Shin Nakajima
Daichi Azuma
OVERVIEW: The electricity grid is essential to the infrastructure of our way of
life and, with protection of the global environment having become a matter of
urgency, there is a strong need for environmental measures based on achieving
greater efficiency in the equipment and systems used in the grid. Hitachi
was among the first companies to research and subsequently commercialize
amorphous transformers that achieve ultra-high efficiency characteristics by
significantly reducing no-load losses (the power consumed by transformers
when idle). Development has been ongoing, with objectives such as larger
capacity and higher quality, and total shipments to date have reached
about 150,000 units. In response to a worldwide demand for environmental
protection that is likely to keep growing in future, Hitachi intends to encourage
greater use of amorphous transformers in Japan and elsewhere through
ongoing strategic technical development and business expansion in which
amorphous materials will also play a role. Through these business activities,
Hitachi will play its part in bequeathing a rich global environment to the future
by reducing transformer losses in the electricity grid.
Trends in Japanese Efficiency Regulations
Japan has led the world in improving the efficiency
of distribution transformers with power companies
having taken the lead in improving the efficiency
of pole-mounted transformer since the 1980s while
Efficiency (%)
INTRODUCTION
THE electricity grid is an essential part of our social
infrastructure, and with moves to protect the global
environment gaining momentum internationally there
is a strong need for environmental measures based
on efficiency gains and other initiatives
that make effective use of the materials
99.5
and equipment that comprise the grid. The
efficiency characteristics of amorphous
transformers are dramatically better than those
of conventional transformers and Hitachi is
99.0
helping protect the global environment
by working on a comprehensive program
extending from materials development to the
technologies used in these transformers.
98.5
This article describes the background to
the development of amorphous transformers
and the benefits achieved by their use in
98.0
Japan.
10
TRENDS IN EFFICIENCY
REGULATIONS FOR DISTRIBUTION
TRANSFORMERS
Transformer efficiency is a subject of global
attention in the electricity distribution industry
and the formulation of efficiency standards is
ongoing in Japan and elsewhere.
Japan: JIS4304 50 Hz
Japan: JIS4304 60 Hz
China: S13 (SiT)
China: S15 (AMT)
USA: DOE Final Rule
EU 50464-1 Ak-Ao
1,000
100
10,000
Capacity (kVA)
SiT: silicon steel transformer AMT: amorphous transformer
DOE: US Department of Energy EU: European Union
Fig. 1—Comparison of Efficiency Standards for Distribution Transformers
(Three-phase Transformers).
While Japan led the world in the introduction of efficiency standards with
its Top Runner Program, other countries are now enacting even higher
efficiency standards.
Hitachi Review Vol. 60 (2011), No. 5
for general industrial transformers, oil-immersed
transformers were added to the Top Runner Program
in 2006 and molded transformers in 2007. Inclusion
in the Top Runner Program has seen total transformer
losses fall by about 30% producing savings of roughly
16,500 GW∙h annually. In terms of CO2 (carbon
dioxide), this corresponds to a reduction in emissions
of about 6.2 million t (based on figures published by
The Japan Electrical Manufacturers’ Association).
To achieve further environmental benefits, work
by government agencies, industry bodies, and others
on introducing the second stage of the Top Runner
Program is already underway with a target date of
2014.
Trends in Overseas Efficiency Regulations
Efficiency standards set by the U.S. Department
of Energy (DOE) came into force in January 2010.
Work is also in progress on formulating more stringent
efficiency standards with a target for implementation
in 2016 (see Fig. 1).
In Europe, the latest-introduced EN50464-1
standard stipulates lower losses than the previous
standard. Also, transformers were added to the
Directive on Eco-Design of Energy Using Products
(EuP), an eco-design framework issued in August
2005 with the aim of increasing the efficiency of
industrial products. A project reviewing this system
is currently underway with the aim of publishing a
standard in 2012 that will come into force in 2013.
In China, meanwhile, which is experiencing rapid
economic growth, the standards for distribution
transformers are being updated to require higher
251
efficiency with the aim of encouraging greater use of
higher-performance transformers so that the provision
of electricity infrastructure will take greater account
of the environment.
As these developments indicate, countries are
vying with each other to find ways of boosting the
efficiency of distribution transformers meaning
that accelerating development of technologies for
amorphous and other types of efficient transformer and
introducing a regulatory regime that encourages their
wider adoption are matters of urgency for Japan if it is
to be a world leader in environment measures.
DEVELOPMENT BACKGROUND
AND FEATURES OF AMORPHOUS
TRANSFORMERS
Hitachi, Ltd. produced a 2-kVA transformer in
1911. This makes the transformer a product with
a long history at the company, dating back to the
same era as the company’s very first product that
was an electric motor. Since then, Hitachi has been
working to make transformers smaller and reduce their
losses while also undertaking developments such as
greater capacity and higher voltage. In particular, it
is anticipated that amorphous transformers will enter
wide use because of their dramatically lower losses
compared to previous types of transformer.
Amorphous Ribbon and Amorphous
Transformers
Amorphous ribbon is produced by melting its main
elements (iron, boron, and silicon) followed by rapid
quenching. “Amorphous” means non-crystalline and
Ordinary metal
Crystalline material with orderly and periodic arrangement of atoms
Melting
furnace
Holding
furnace
Casting with ultra-rapid quenching
(cooling rate: 106°C/s approx.)
transforms molten alloy into ribbon
without recrystallizing
Amorphous
Nozzle
Casting roll
• Magnetic domains cannot move easily
during magnetization.
• Properties such as crystal orientation and
grain size can be manipulated by working
and heat treatment.
Non-crystalline with disordered random arrangement of atoms
Casting control
Ribbon coiler
• Magnetic domains can move easily during
magnetization due to lack of magnetically
anisotropic crystals.
→ Excellent soft magnetic properties and
low losses
• Induced magnetic anisotropy can be achieved
by heat treatment in a magnetic field.
Fig. 2—Features of Amorphous Ribbon and its Production Process.
A casting process with ultra-rapid quenching is used to transform molten alloy into ribbon without recrystallizing. The noncrystalline structure and ultra-thin material characteristics provide superior soft magnetic properties and low losses.
Amorphous Transformer Contributing to Global Environmental Protection
Development of the underlying technology started
in the early 1980s. Pole-mounted transformers for
power companies were released in 1991 followed by
a general industrial transformer in 1997. Since then,
Hitachi has been filling out its product range and has
been improving further performance with the result
that over 150,000 units have been shipped in 20 years
since entering the market. With the aim of making its
transformers truly environmentally conscious, Hitachi
established a recycling system of amorphous alloy
that has been adopted by some of power companies
since 2008.
Regarding Hitachi’s materials business, Hitachi
Metals, Ltd. acquired the amorphous products business
of Honeywell International Inc. (USA) in 2003 and
established a new production facility at its Yasugi
Works in Shimane Prefecture, Japan in 2007 in addition
to its US plant. Together, these provide an annual
capacity of 100,000 t to meet the growing demand for
amorphous ribbon from around the world.
Bushing
Core
Winding
Tank
Amorphous ribbon
Fig. 3—Amorphous Transformer Structure and Amorphous Ribbon.
Dramatically lower losses can be achieved by using amorphous
ribbon (approximately 25 µm thick) for the core.
alloy ribbon can be produced by rapid quenching
whereby the material solidifies with the metal atoms
in random arrangements rather than forming a periodic
crystalline structure (see Fig. 2).
Conventionally, silicon steel has been used as the
transformer core material and while steel makers have
made great advances in its properties, Hitachi was the
first to turn its attention to amorphous transformers
that use amorphous ribbon as their core material and
engage in active development of the product in order
to reduce losses further (see Fig. 3).
Features of Amorphous Transformers
Transformer losses can be broadly divided into
the no-load loss that occurs continuously regardless
of the load and the load loss that is proportional to the
square of the load current. Amorphous transformers
have very low no-load losses giving them much lower
Background to Development of Amorphous
Transformers
Fig. 4 shows the history of amorphous transformer
development and application by Hitachi.
USA
1960
1980
1985
1990
1995
Hitachi
2000
2005
Development
Growing number of
Use in power
Commercialization
Fewer installations (except
Development
of underlying
installations for new
distribution
and wider use
for some three-phase models)
of amorphous
technology
energy applications
resumes
metal
(Westinghouse Electric
Corporation) Development
Acquisition of
Development and practical
Pole-mounted
(California Institute
of technology for
amorphous
application of high magnetic
of Technology)
transformer released
mass production
business (2003)
flux density materials (2006–)
(General Electric Company)
Market trends, etc. (Japan)
252
Development
of underlying
technology
Development
of technology for
mass production
Pole-mounted
transformer
field test
General industrial transformer
released: Larger capacities,
wider product range (Super
Amorphous transformer)
April 1999
amendment to Energy
Conservation Law
Japanese production of
amorphous materials
begins (2007–)
Added to Top Runner Program
Oil-immersed: April 2006,
Molded: April 2007
UN approves CDM methodology for CO2 reductions using
energy efficiency amorphous transformers (Mar. 2008)
Hitachi’s ultra-energy-efficient
amorphous transformer
wins 10th Energy Conservation
Grand Prize (Feb. 2000)
Energy-efficient
transformers included in
investment tax incentives
for encouraging
rationalization of energy
supply and demand
(Apr. 2000)
Recycling system
established (2008–)
Hitachi’s ultra-energy-efficient
amorphous transformer
wins Governor of Tokyo’s Prize
at Electrical Construction
Equipment and Materials Fair
(June 2007).
UN: United Nations CDM: clean development mechanism CO2: carbon dioxide
Fig. 4—History of Amorphous Transformer Development and Application.
Hitachi started development at an early stage and undertook comprehensive technical and business development covering everything
from materials to the transformer itself to satisfy society’s need for environmental protection.
253
Hitachi Review Vol. 60 (2011), No. 5
99.8
Oil-filled
transformers
Molded
transformer
Amorphous Transformer
High Efficiency Series
99.6
Efficiency (%)
Amorphous Transformer
Super High Efficiency Series
200%
Amorphous Transformer
High Efficiency Series
Efficiency
relative to
Top Runner
standard
99.4
99.2
Amorphous Transformer
Compact Series
JIS C 4304 standard
(rated load factor)
98.8
98.6
0
20
40
60
80
100
Load factor (%)
Standard Silicon Steel
Transformer
100%
Top Runner standard
(40% load factor)
99.0
Amorphous Transformer
Compact Series
Standard Silicon Steel
Transformer
Amorphous Transformer High Efficiency Series
Amorphous Transformer Compact Series
Standard Silicon Steel Transformer
Mean load factor
2,000
Power consumption
CO2 emissions
1,500
Loss (W)
Fig. 5—Amorphous Transformer Product Range.
When choosing a transformer, it is important to consider the
actual load factor and choose the best possible model based on its
efficiency characteristics. Hitachi has a number of different series
of amorphous transformers to suit different customer needs.
Load loss (W)
No-load loss (W)
11.4 MW·h/year
6.2 t/year
10.6 MW·h/year
5.8 t/year
7.1 MW·h/year
3.9 t/year
1,000
694
1,008
554
500
602
0
losses than conventional transformers. They have
particularly good efficiency when used as distribution
transformers commonly at mean load factor of around
20 to 30%(1), (2). Hitachi has an extensive range of
transformers including silicon steel models so that
customers can select the transformer that best suits
their load factor (see Fig. 5 and Fig. 6).
260
200
Amorphous Transformer Amorphous Transformer
High Efficiency Series
Compact Series
(highly efficient
(highly efficient
over all loads)
in mean load range)
Standard Silicon
Steel Transformer
Note: Losses when operating with a load factor of 40%,
CO2 emissions per unit of energy is 0.555 kg/kW·h.
Fig. 6—Features of Amorphous Transformers (3 Phase, 500 kVA, 50 Hz).
Amorphous transformers have a very low no-load loss and a good
efficiency particularly in the low load range where generally
transformers are operated.
Coercive force Electric resistivity
Iron loss
Magneto-striction Sheet thickness Lamination
factor SF (%)
HC (A/m)
P13/50 (W/kg)
t (mm)
ρ (µΩ · m)
λs (ppm)
Material
Saturation flux
density BS (T)
Grain-oriented electrical steel
(Si steel) (highest grade)
2.03
45.0
0.5
0.440
−1
0.23
>95
Amorphous
material (2605SA1)
1.56
2.0
1.3
0.070
27
0.025
>84
New amorphous
material (2605HB1)
1.64
1.5
1.3
0.063
27
0.025
>84
Remarks
Higher values
allow smaller size.
Lower values
produce
lower losses.
Higher values
produce
lower losses.
Smaller
is better.
Lower values
mean quieter
operation.
2.0
Higher BS
Grain-oriented
electrical steel (Si steel)
Bs=1.56
Flux density B (T)
1.5
10
f=50 Hz
2605HB1
P13/50=0.070
Lower iron loss
2605SA1
Iron loss (W/kg)
Bs=1.64
1.0
0.5
1
Grain-oriented
electrical steel
(Si steel)
0.1
Hc=1.5
0
Hc=2.0
20
40
Magnetic field, H (A/m)
60
Higher BS
2605SA1
Lower HC
Measured by single-sheet method
0
−20
Higher values
Thicker is
allow smaller
easier to work.
size.
2605HB1
Amorphous alloy
80
0.01
0.4
0.6
0.8
1.0
1.2
1.4
P13/50=0.063
1.6
1.8
2.0
Flux density (T)
Fig. 7—Characteristics of 2605HB1 Amorphous Material with High Magnetic Flux Density.
To improve transformer performance and specifications, Hitachi is working on comprehensive developments extending from materials
to techniques for their application in transformers. The benefits of using 2605HB1 include lighter transformers with lower losses.
Amorphous Transformer Contributing to Global Environmental Protection
Single-phase power transformer 6 k/210 V 20 kVA 60 Hz
SiT
AMT(SA1)
AMT(HB1)
External diameter (mm)
Height (mm)
Weight (kg)
No-load loss (W)
Load loss (W)
Total
loss
(W)
Rated load
40% load
AMT
(2605SA1)
364
(100)
713
(100)
138
(100)
61
(100)
281
(100)
342
(100)
106
(100)
385
(104)
740
(104)
170
(128)
22
(36)
285
(102)
307
(90)
68
(64)
355
(98)
707
(99)
148
(107)
17
(27)
280
(100)
297
(87)
62
(58)
New AMT
(2605HB1)
SiT
Fig. 8—Comparison of Specifications for Transformers Using
2605HB1.
Use of 2605HB1 allows amorphous transformers to be
produced with similar dimensions and weight to existing silicon
steel transformers.
Use power supply monitoring unit to review loads.
Power supply monitoring units : 65
• Used to monitor 965 points
(power consumption: 65 points,
power factor and other parameters: 900 points)
Pulse input units
: 20
Monitoring PC • Used to monitor 108 points
(power consumption: 108 points)
Repeaters
:2
Power supply
Pulse
Insulation
monitoring unit input unit monitoring unit
Repeater
Repeater
RS-485
Trends in Technology Development for
Amorphous Transformers
Due to its lower saturation flux density than that
of silicon steel, amorphous transformer has some
disadvantages such as in size and weight. Amorphous
transformers are larger and heavier than silicon steel
transformers. To resolve this problem, Hitachi Metals,
Ltd. embarked in 2003 on development aimed at
increasing the saturation flux density based on iron
base amorphous alloy: 2605SA1. This led to the
2605HB1 high-flux-density material entering full-scale
production in 2005. Fig. 7 shows the characteristics of
this new material with its superior flux density.
Because it was anticipated that use of 2605HB1
would have many benefits including making the
amorphous transformers smaller, lighter, and quieter,
work on incorporating the new material into the
transformer was undertaken in parallel with material
development(3). It was first used by a power company
in 2006 and is increasingly being adopted in general
industrial transformers (see Fig. 8).
The product is also attracting attention overseas
where it is expected that amorphous transformers
will become more widely used in future and Hitachi
is working to further improve its performance and
reduce costs.
Consolidate number of units
and adopt AMTs.
48 transformers
(15,405 kVA)
Silicon steel transformers
33 transformers
(11,285 kVA)
Savings from reduced losses
Power losses (MW•h/month)
Item
254
70
60
50
40
30
20
10
61.1
Load loss
15.8
No-load loss
45.3
19.2
15.6
3.6
0
Before upgrade After upgrade
Economic benefit: 5,531,000 JPY/year
CO2 reduction: 900 t/year
Amorphous transformer
Note: CO2 emissions per unit of energy:
0.555 kg/kW•h
PC: personal computer
Fig. 9—Case Study of Benefits of Amorphous Transformer Installation.
Hitachi Industrial Equipment Systems succeeded in reducing power losses to one-third of their previous level at its Nakajo Division
by consolidating transformer numbers and adopting amorphous transformers, thereby achieving significant economic benefits while
reducing the burden on the environment.
Hitachi Review Vol. 60 (2011), No. 5
BENEFITS OF INSTALLING AMORPHOUS
TRANSFORMERS
As explained above, the low loss characteristics of
amorphous transformers provide significant benefits
for energy conservation and reducing the burden on
the environment.
Case Study of Installation at Hitachi Industrial
Equipment Systems’ Nakajo Division
Nakajo Division, Hitachi Industrial Equipment
Systems Co., Ltd. is fed by a 66-kV line that is
stepped-down to 6 kV for distribution around the
site. The 6-kV supply is further stepped-down at each
production facility to provide the low-voltage supply
to the various equipment. To conserve energy and
reduce unit emissions of CO2, electricity distribution
monitoring systems were installed at each production
facility in 1997 to make visible the electricity usage of
each production line. When aging transformers were
subsequently upgraded, the results from these systems
were used to determine the number and capacity of
new transformers based on the operating conditions
at each production line and a significant reduction
in electric losses was achieved by using amorphous
transformers throughout (see Fig. 9).
Estimate of Benefits from Installing Amorphous
Transformers in Japan
Amorphous transformers are making a major
contribution to reducing CO2 emissions with a total
of approximately 400,000 currently in use made up of
about 390,000 pole-mounted transformers for power
companies (including those from other suppliers)
and about 12,000 general industrial transformers
(including both oil-immersed and molded).
TABLE 1. Benefits of Installing Amorphous Transformers
(Across Entire Grid in Japan)
Although the benefit per transformer is small, the large number of
distribution transformers in use means the total benefit is large.
User
Average
Loss reduction
No. in use
capacity
(×10,000)
(kW/transformer)
(kVA)
CO2 emissions
CO2
per unit of
reduction
energy
(t/year)
(kg·CO2/kW·h)
Power
companies
39.0
20
0.04
0.453*1
61,900
General
industry
1.2
500
0.95
0.555*2
55,500
Total
40.2
–
–
–
117,400
*1: Mean actual value for power use in Japan in 2007 published by The Federation
of Electric Power Companies of Japan
*2: Default value stipulated in the directive on estimating greenhouse gas
emissions resulting from the business activities of certain emitters (Ministry of
Economy, Trade and Industry/Ministry of the Environment Directive No. 3, 2006)
255
This achieves a big reduction in the burden on the
environment, corresponding to a reduction of roughly
120,000 t/year in CO2 emissions, and it is anticipated
that use of these transformers will continue to grow
in Japan and elsewhere (see Table 1).
CONCLUSIONS
This article has described the background to the
development of amorphous transformers and the
benefits achieved by their use in Japan.
Amorphous transformers are also attracting
attention in other countries. Installation of amorphous
transformers is currently growing rapidly in Asia,
particularly in China and India where environmental
measures are being adopted in parallel with the
provision of infrastructure. It is also expected in
future in America and Europe that measures aimed at
protecting the environment lead to the prevalence of
high performance transformers(4) and it is predicted
that use of amorphous transformers will expand all
around the world.
To respond to the social requirement, Hitachi
contributes to keeping a rich global environment for
the next generation by supplying products and service
protecting with environmental measures in the power
distribution field.
REFERENCES
(1) M. Takagi et al., “An Evaluation of Amorphous Transformer
Using Load Curve Pattern Model for Pole Transformer,”
IEEJ Transactions on Power and Energy 128, pp. 885−892
(2008).
(2) “Potential for Global Energy Savings from High Efficiency
Distribution Transformers,” Leonardo Energy Transformers
(Feb. 2005).
(3) A. Sato et al., “Development of Distribution Transformer
Based on New Amorphous Metals,” CIRED2009 Session 4
Paper No. 0474 (2009).
(4) “Amorphous Metal Transformer: Next Steps,” EPRI White
Paper, Electric Power Research Institute (Jul. 2009).
Amorphous Transformer Contributing to Global Environmental Protection
256
ABOUT THE AUTHORS
Katsutoshi Inagaki
Masanao Kuwabara
Joined Hitachi, Ltd. in 1990, and now works at the
Transformer Design Department, Power Distribution
& Environmental System Division, Commercial
Division, Hitachi Industrial Equipment Systems
Co., Ltd. He is currently engaged in the design and
development of electrical distribution equipment and
materials. Mr. Inagaki is a member of The Institute of
Electrical Engineers of Japan (IEEJ).
Joined Hitachi, Ltd. in 1997, and now works at the
Transformer Design Department, Power Distribution
& Environmental System Division, Commercial
Division, Hitachi Industrial Equipment Systems
Co., Ltd. He is currently engaged in the design and
development of oil-immersed transformers.
Kohei Sato
Kazuyuki Fukui
Joined Hitachi, Ltd. in 1999, and now works at the
Transformer Design Department, Power Distribution
& Environmental System Division, Commercial
Division, Hitachi Industrial Equipment Systems
Co., Ltd. He is currently engaged in the design and
development of molded transformers. Mr. Sato is
a member of the IEEJ.
Joined Hitachi Nakajo Technology, Ltd. in 2001, and
now works at the Transformer Design Department,
Power Distribution & Environmental System Division,
Commercial Division, Hitachi Industrial Equipment
Systems Co., Ltd. He is currently engaged in the
design and development of transformers for power
companies.
Shin Nakajima
Daichi Azuma
Joined Hitachi Metals, Ltd. in 1982, and now works at
the Soft Magnetic Materials Company. He is currently
engaged in research and development of amorphous
alloys for transformers. Mr. Nakajima is a member of
the IEEJ.
Joined Hitachi Metals, Ltd. in 2001, and now works at
the Soft Magnetic Materials Company. He is currently
engaged in research and development of amorphous
alloys for transformers. Mr. Azuma is a member of
the IEEE.