Sumitomo Electric Group Magazine

18

vol.
Innovative Development,
Imagination for the Dream,
Identity & Diversity

FeatureConnecting to the Future of Decarbonized Society

At the Forefront of
Direct Current Power
Transmission Cables

Connecting to the Future of Decarbonized Society

At the Forefront of Direct Current
Power Transmission Cables

Essential to the Growth of
Renewable Energy, HVDC Cable
Is the Key to Long-Distance andHigh-Capacity Transmission.
In autumn 2021, COP26 was held in Glasgow, Scotland, after a one-year postponement due
to the COVID-19 pandemic. Many national representatives who took the podium declared
their commitment to carbon neutrality by 2050 and announced interim targets to realize
their goals. Japan launched the clean energy strategy to attain its goal.
To realize a decarbonized society, it is imperative to expand the use of renewable energy.
Wind farms, which are expected to play a key role, must be built offshore or at remotelocations by taking into account the weather conditions and environmental impact. Longdistance power transmission is required to connect wind farms with major power
consumption areas. Long-distance and large-capacity power transmission is also
indispensable for inter-regional connection to ensure a stable supply of electric power toimplement measures against power outages, which are caused by recent earthquakes andextreme weather events, and meet the growing demand.
Direct current cross-linked polyethylene (DC XLPE) cables have attracted public attention
as cables capable of transmitting a large amount of electricity over a long distance. Thisissue focuses on the frontline operations of Sumitomo Electric, which directly contributes toa decarbonized society by offering DC XLPE cables, which are essential for the widespreaduse of renewable energy.
02

03

DC XLPE Cables Accelerate
the Use of Renewable Energy– “DNA” of Developers Passed on to Date –ColumnPower transmission equipment for
sending and receiving electricity
between countries or regions is called
an interconnector. The global
community, which has been moving
toward a decarbonized society, aims tocreate a future where electricity isinterchanged in a large area by using
international and interregional grids
consisting of interconnector networks.
In line with these developments in theenergy market, Sumitomo Electric has
been awarded contracts forinterconnector projects to manufacture
and install DC XLPE cables.
DC power transmission cables offer
advantages in long-distance and largecapacity power transmission. DC XLPE
cables, which use cross-linked
polyethylene as an insulating material,
have less environmental impact
compared to that of oil-impregnatedinsulation cables. As a front runner,

Sumitomo Electric became the firstcompany in the world to achieve
normal operation with the conductor
temperature at 90°C, which is 20°C
higher than that of conventional
cables, and polarity reversal of powertransmission voltage. This has achievedlarge-capacity power transmission,leading to the development of an
innovative high-voltage DC (HVDC)
cable capable of changing the voltage
direction depending on the operation
status of a DC interconnector (i.e.,changing the direction of sending
electric power by reversing the polarityof the positive and negative terminals).
Electric power companies aroundthe world awaited the development of
this power transmission cable.
However, even after the advent of the

21st century, there were no reports thatXLPE cables, which went into practicalapplication and widespread use in the
1960s for alternating current (AC),were developed for direct current (DC).
Against this backdrop, the HokkaidoHonshu HVDC Link, a submarine cableinstalled by Sumitomo Electric in 2012,
became the first HVDC powertransmission line using XLPE cables.
How did Sumitomo Electric develop
DC XLPE cables? Let’s take a look at
the history of the development to fulfill
the long-cherished dream.

Challenging spirit passed on to date
The history of Sumitomo Electric
dates back to 1897, when Sumitomo
Copper Rolling Works was founded to■ Types of cables
Types ofinsulation

Oil-impregnated insulation
OF cable
Low-viscosity oil ispressurized into insulation
paper and sealed.

Solid insulation

MI cable

XLPE cable

High-viscosity oil isimpregnated into insulation
paper and sealed.

An additive for preventing
accumulation of electric charge ismixed in the cross-linked polyethylene.

Structure

XLPE cable

04

Long
distanceLarge
capacity

△
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○

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manufacture and sell copper sheets,
rods, and wires using copper producedin the Besshi copper mine as the raw
material. In 1905, the refinery was
relocated to Shisakajima, an
uninhabited island in the Seto Inland
Sea. In 1922, the longest submarine
cable in the world at that time(spanning 21 km) was completed
between Niihama and Shisakajima toachieve stable supply of electric power.
The persevering commitment to inhouse manufacturing, no matter how
much time it takes, is considered as
the identity of Sumitomo Electric,
underpinned by the challenging spirit,
which has been passed on to datefrom Shisakajima. Sumitomo Electric
has always taken the lead in thedevelopment of various powertransmission cables.
The first DC power transmission
cable in the world went into

Basic knowledge of DC and AC

There are two types of electricity
flow: DC and AC. In DC, electricity
flows in one direction from thepositive terminal to the negative
terminal as in the case of a dry
battery. In AC, electricity flows backand forth alternatingly like waves
between the positive and negative
terminals. Electricity generated at a
power plant is delivered to homes in
AC. Thus, most electricity used athome is AC.
Why is AC used dominantly? The
reason dates back to the latter halfof the 1880s, when Thomas Edison
and Nikola Tesla, both of whom were
inventors, clashed over which should
be used for future electric powersystems: DC or AC. Edison started
DC power transmission for lightbulbs
for the first time in the world.
However, he faced problems inlong-distance power transmission
due to difficulties in voltage
conversion, which could not be
achieved by the technology at thattime, and costs incurred by ultrathick copper wires required for
power transmission. Meanwhile, Tesla
started AC power transmission. He
achieved long-distance powertransmission through the process ofhigh-voltage power transmission,
step-down, and power receiving by
taking full advantage of thecharacteristics of AC, whose voltage
was easy to change, on a scale farlarger than that of Edison’s electric
power system. In addition, AC was

DC XLPE cable wound on a turntable and waiting for shipment

Long-cherished DC XLPE cables

DC XLPE cable during shipment

commercial operation in 1954 between
Sweden and Gotland. Since then,oil-filled (OF) cables as well as massimpregnated (MI) cables, both of which
consisted of wrapped and impregnatedpaper as an insulationmaterial, were used
as DC powertransmission cables
for many years.
However, there was
growing demand forinsulation cables that
did not pose the riskof oil leakage fromthe viewpoint ofenvironmental
protection in line withthe growing
awareness about
environmental issues
around the world.
Research on DC
XLPE cables started
in Japan in the latter

Installation of a submarine cable and Shisakajima
submarine cable at that time (cross section of the cable)

more suitable than DC for
infrastructure because the equipment
was less expensive and themaintenance cost was low. Thus, AC
is used in most of the grids aroundthe world, including Japan.
Today, electronic devices which
require complicated control, such as
PCs and smartphones, are operated
by DC by using AC adapters, whichconvert AC to DC. Inverters, which
are used in air conditioners andrefrigerators, also convert AC to DC
to achieve complicated control andenergy conservation. DC is highly
compatible with charging and isconsidered to be suitable for electricvehicles and charging equipment (i.e.,suitable for renewable energy). A
new era, which Edison might haveushered in, is finally beginning. DC
may play a key role in the nextgeneration electric power system.
DC

AC

Voltage
Voltage

Voltage
Voltage
DCDC

00

AC
AC
Time
Time

The voltage and direction
are constant.

00

Time
Time

The voltage and direction
are variable.

half of the 1970s. At that time, longterm electrical tests were conducted touse AC XLPE cables, which werealready in practical application, as DC
XLPE cables without modification.
However, it was found that AC XLPE
cables could not be used for DC as is,due to the negative effect of the spacecharges (discussed later), whichaccumulated in the insulating material.
Based on the results, Sumitomo
Electric promoted the basic
development of DC XLPE insulating
material in 1984 in response to thedevelopment request from ElectricPower Development Co., Ltd.
(“J-POWER”).
Note) Sumitomo Electric established J-Power
Systems Corporation (“JPS”) in 2001 by
consolidating Hitachi Cable, Ltd. with the High
Voltage Power Cable Div. In 2014, it made JPS a
wholly owned subsidiary. In 2022, it succeeded
JPS’s business related to manufacture of electric
wires and cables.

05

electrical resistance and allowing a large
current to flow.

Obstacle posed by spacechargeIn 1979, J-POWER completed
the first-stage submarine cablefor the Hokkaido-Honshu HDVC
Link, which connected
Hokkaido with Mainland Japan,
and started operation.
However, the installed cable
was the oil-impregnatedinsulation type. Thus, thecompany hoped to use the DC
XLPE cable for expansion or
renewal from the viewpoint ofenvironmental protection.
Mitsumasa Asano of J-POWER(at that time), who worked on
the development with
Sumitomo Electric, looked backon the situation and said, “I felt
the passion of Sumitomo
Electric’s development teammembers, who showed
extraordinary perseverance toaccomplish the project
whatever it might take.”“The biggest obstacle was
how to suppress the spacecharges. Electric charges, which
are invisible, refer to theamount of electricity withwhich an object is charged. The
electric charges that
accumulate in an insulating
material when DC voltage isapplied are referred to as‘space charges.’ These prevent
an insulating material from fully
demonstrating its performance.
Electrical breakdown* may
result when a powertransmission system is hit bylightning. This was the biggest
factor that prevented
application of XLPE cables to
DC. When we conductedvarious tests to eliminate thespace charges, Sumitomo
Electric made an
unconventional proposal. ‘Even
if the electric charges arepresent, electrical breakdown

A revolutionary idea to mix anadditive

Devotion to the Developmentof DC XLPE Cables– An Inside Story on the Development of a Special Filler Material –may not occur when the electriccharges are evenly and uniformly
scattered in an insulating material.’
Thus, we decided to use a method of
adding a filler material to the crosslinked polyethylene,” said Asano.
The insight was right. After trial anderror, the space charges were finallysuppressed by adding a newly
developed special filler material. R&D
proceeded from Stage 1 (1988 to 1995),
which aimed to attain 250 kV, to Stage
2 (1993 to 2001), which aimed to attain500 kV. All the targets were achieved.
This coincided with the deteriorationof the first cable installed for the
Hokkaido-Honshu HDVC Link.
In 2012, the DC XLPE cable
was finally put to practicalapplication for the first timein the world to meet the
replacement needs.
“In the actual manufacturing
operations, it was necessary
to fabricate a long-distancecable. This posed difficulties
in maintaining uniform quality
compared to the prototype
production. It was highlymeaningful to holddiscussions between the twocompanies about the quality
control and manufacturing
process,” said Asano.
Asano also remembered

Cable installation for the Hokkaido-Honshu HDVC Link

06

Let’s meet a legendary
person who has focused on DC
XLPE cables throughout his
research career. Shoshi Katakai
is affiliated with the Electric
Wire & Cable Energy Business
Unit. He has been devoted to
R&D of DC XLPE cables sincethe 1980s, when he entered theindustry.
“I spent frustrating years.
However, many customers
waited for the practicalapplication of cables capableof large-capacity powertransmission with minimal
environmental impact, so R&D
never stopped,” said Katakai.
The development of 500 kV
AC XLPE cables was in fullswing when Katakai started towork on research. Cross-linked
polyethylene (XLPE), which is
the key insulating material,
significantly improved theproperties of polyethylene athigh temperature by crosslinking, which is a method ofchanging the molecular
structure.
“To make XLPE an insulating
material capable of coping withhigher voltages, R&D members
were expected to prevent
defects, by entering no defects,
producing no defects, andbeing able to prove no defects
existed. The ideal was todevelop the purest possible
Long-term electrical test site (Osaka Works)polyethylene without mixing
additives,” said Katakai.
This approach wasconsidered to be applicable tothe insulating material of DC
power transmission cables.
However, a new problem, which
did not arise in the AC powertransmission cables, emerged.
Conventional XLPE attained
the electrical breakdown
strength far below the
expectations for the DC
voltage due to accumulation of
the space charge, which was
discussed above. In otherwords, AC XLPE cables madefrom pure polyethylene could
not be used as they were for
DC. Thus, Katakai came up with
the idea of mixing an additive
Completed cableand decided to use a filler
material. He made steadfast
Sumitomo Electric’s workers wereefforts to carefully identify potential
reliable in terms of both skills andfiller components one by one to cope
construction management,” said
Asano.
The project was accomplishedthanks to Sumitomo Electric’s overallcapabilities: development engineers
who perseveringly pursued
outstanding specifications, in-depth
quality control at the manufacturingsite, careful construction work which
took full advantage of the quality, andpassion to attain high levels on all
aspects.

what impressed him during the
installation work.
“The offshore cable had to beconnected with the onshore cablemanually. Accidents were likely tooccur at this point in the cable
construction project. This process
required high engineering capabilities.

* When the strength of an electric field thatapplies to an insulating material exceeds athreshold, the insulating material electricallybreaks down, resulting in a rapid decrease in
Mitsumasa Asano
Director, Business Planning & Management Dept., J-POWER
Transmission Network Co., Ltd.

Shoshi Katakai, fellow of the Electric Wire &Cable Energy Business Unit

with high voltages and finallydetermined the components andblending to resolve the problem.
Efforts to achieve further
miniaturization and higher purificationand distribution led to a special filler
material. A material with superb DC
insulation characteristics wascompleted by uniformly distributing
the components in XLPE. This is the
proprietary XLPE that underpins HVDC
power transmission cables currently
manufactured by Sumitomo Electric.
The accomplishment was derived fromdoubting the conventional wisdom andseeking the truth with perseverance.
“‘Seek the Truth’ – I have only
followed the teaching in good faithfrom my teacher when I was astudent,” said Katakai with deep
emotion. In the 2000s, a consortium
was organized with a university to
publicly evaluate the results.
Preparations were made towardcommercialization. However, there wasno project to use DC XLPE cables. It
took some more time until practicalapplication. The situation changed in
the 2010s. After the Great East Japan
Earthquake in 2011, there was a
growing need for electric powerinterchange between electric powercompanies. Coincidentally, the DC
XLPE cable went into operation in the
Hokkaido-Honshu HDVC Link in 2012.
At present, Katakai focuses on
training younger engineers as a fellowof Sumitomo Electric, but he remains
highly motivated to work on thedevelopment.
“Interconnectors have been
expanded worldwide, but more ofthem are needed,” said Katakai.
The Japanese government hasannounced a plan to construct a nextgeneration grid to send electric power
derived from renewable energy
sources, such as offshore wind power,
from Hokkaido to Tohoku and Tokyo as
part of its clean energy strategy. In
Europe, where the electric power
market has been liberalized,
construction of an international gridcalled “super grid” is underway as thefirst project of its kind in the world.
The development of international
interconnectors has been spurred by
the growing need to introduce
renewable energy. Full-scale efforts
have been launched by regions andcountries to achieve carbon neutrality.
The supply of DC XLPE cables, whichwere developed by Katakai and other
Sumitomo Electric engineers, will be
accelerated for interconnector projects
in and outside Japan.

Electrical test07

Cable drawn in and placed on a rack on the ceiling

Service tunnel during cable installation
Ceremony to draw in the cable (Yoshioka construction base)■ Installation route of the New Hokkaido-Honshu HVDC Link
Hokuto C/S

Hakodate C/S

Cable connection room: Workers made efforts toimplement dustproof measures in the severe
environment.

New Hokkaido-Honshu HVDC Link
Hokkaido-Honshu HVDC Link

Overhead cable: 77 km

Hokkaido

Connecting Regions
for Stable Supply ofElectric Power– New Hokkaido-Honshu DC Seikan Tunnel Project –A major power outage that could havebeen avoided
In September 2018, the Hokkaido
Eastern Iburi earthquake caused alarge-scale power outage across theentire Hokkaido area.
At that time, the test operation of
the New Hokkaido-Honshu HVDC Link,
whose entire construction process had
been completed, was about to begin
toward commencement of its
commercial operation in March 2019.
As discussed above, the HokkaidoHonshu HDVC Link (submarine cable)
was already in place between Hokkaido
and Mainland Japan. Its operation wasstarted by J-POWER in 1979. When the
demand for electric power was high in
Hokkaido, a stable supply was ensured
through the electric power interchange
from Mainland Japan. Subsequently,
the second cable was installed in 1993,
and the first cable that had
deteriorated was replaced by the DC
XLPE cable in 2012 (total powertransmission capacity: 600 MW). The
New Hokkaido-Honshu HVDC Link was
designed to add the 300 MW capacity
to constantly stabilize the electric
power supply in Hokkaido. The New
Hokkaido-Honshu DC Seikan Tunnel
project was initiated to construct anunderground power transmission linein the Seikan Tunnel.
08

Tomoyuki Fukushima, who led the
project as Director of the Trunk
Network Work Center of Hokkaido
Electric Power Co., Inc., explained how
he felt at that time.
“Expansion of the interconnector
had been planned previously to copewith the suspension of the HokkaidoHonshu HDVC Link and large-scale
repair in the future. Planned power
outages following the Great East Japan
Earthquake expedited efforts toenhance electric power interchange
and expand interconnectors. The
investigation and design of the New
Hokkaido-Honshu HVDC Link started
two months after the earthquake. The
project aimed to start operation in five
years after commencement ofconstruction, which was short in termsof the construction period for aninterconnector. I remember how I felt
frustrated every time I was told ‘thepower outages across Hokkaido could
have been avoided if the New
Hokkaido-Honshu HVDC Link had beenin place,’” said Fukushima.

Sumitomo Electric. Fukushima was the
responsible person who formulated thebasic plan. He admitted that hesometimes felt anxious about whether
the project would be successful.
“We decided to install the cable in
the Seikan Tunnel because the space inthe tunnel was accessible to workers
to visually check the cable after
commencement of the operation. It
was easy to conduct inspection andmaintenance. It should be noted thatthe cable was to be installed in theservice tunnel, which ran parallel withthe main tunnel for the Shinkansenbullet train and was far smaller thanthe main tunnel. The installation space
was near the ceiling, but both the
installation space and work space wereTaking on a challenge to cope withthe severe tunnel environment
The cable was to be installed in the
Seikan Tunnel. This was anunprecedented challenge for both
Hokkaido Electric Power andTomoyuki Fukushima
Northern Advancement Center for Science & Technology (NOASTEC)(Executive Officer of Hokkaido Electric Power Co., Inc.)

Submarine cable: 43 km(Tsugaru Channel)

Cable in the tunnel: 24 km (Seikan Tunnel)
Overhead cable: 21 km
Imabetsu C/SAomoriKamikita C/S

Imabetsu converter station

Installation (on the Hokkaido side: Yoshioka cablehead (draw-in port))

Hokuto converter station
Tsugaru
ChannelMainland Japan

Hokkaido
Seikan Tunnel
Undergroundpart: 24 km
122 kmCross section of the New Hokkaido-Honshu HVDC Link route (courtesy of Hokkaido Electric Power Network, Inc.)(The New Hokkaido-Honshu HVDC Link connects the Hokuto converter station on the Hokkaido side with the
Imabetsu converter station on the Mainland Japan side. The New Hokkaido-Honshu DC Seikan Tunnel project
aimed to construct a 24 km underground power transmission cable in the Seikan Tunnel.)very small, so we had to makearrangements to adapt the design,
construction method, and on-sitemanagement to the environment in thetunnel,” said Fukushima.
One year was spent to investigate
the environment in the tunnel,
formulate a route plan, and determine
the equipment configuration.
Sumitomo Electric participated in the
project from the investigation phase.
The situation was identified carefully toperform the construction work safely
and reliably. Nevertheless, various
problems, both major and minor ones,
arose every day after commencementof the construction work.
“The submarine tunnel wascompletely dark, and humidity in thetunnel was always over 80%. In
addition, a cloud of dust blew up dueto the air pressure when Shinkansenbullet trains passed in the main tunnel.
Despite such a construction
environment, it was almost a miracle tocomplete the interconnector
construction project in five years asplanned, which usually takes eight to10 years. It is difficult to explain in aword, but as I look back, the success
was attributable to the efforts todiscuss issues, which emerged one
after another, with all the members andresolve them without compromise
through concerted efforts. Above all,Sumitomo Electric’s engineering
capabilities played a key role to deliverthe 24 km-DC XLPE cable in a shortperiod,” said Fukushima.

Growing demand for DC
interconnectors in JapanThe large-scale power outage in2018 stirred up discussions about theimportance of interconnectors. The
New Hokkaido-Honshu HVDC Link
became the first interconnector inJapan to use a voltage-sourced AC-DC
converter, which was just developedfor HVDC in the 1990s. “DC XLPE
cables, which can be used for any DC
conversion methods, are derived fromthe high development and engineering
capabilities of Sumitomo Electric. This
was a valuable project for Sumitomo
Electric,” said Kazutoshi Abe of thePower Cable Project Engineering Div.
with confidence.
“The DC grid is like an expressway tointerchange electricity in a large area,
while the regional grid is a generalroad to send electricity to homes andcompanies. AC is used for the generalroad, so an AC-DC converter serves as
an interchange of roads. There are two

Kazutoshi Abe
Electric Cable Project Div.

types of AC-DC converters: linecommunicated converters and voltagesourced converters. Sumitomo
Electric’s DC XLPE cables can be used
for both AC-DC conversion methods.
The New Hokkaido-Honshu HVDC Linkis the first project in Japan to apply the
DC XLPE cable to the voltage-sourced
AC-DC converter. The needs for similar
specifications will grow in the field ofinterconnectors. Sumitomo Electric
built a track record befitting the selfacknowledged top brand of DC powertransmission cables,” said Abe.

One big step forward in theinterconnector scheme
Having seen the completion of the
New Hokkaido-Honshu HVDC Link,
Fukushima is currently engaged inindustrial promotion in Hokkaido at theNorthern Advancement Center for
Science & Technology (NOASTEC), towhich he has been temporarilytransferred.
“Zero Carbon Hokkaido is part of the
Basic Policy on Economic and Fiscal
Management and Reform promoted by
the Japanese government. Hokkaido
offers the biggest potential in Japan interms of renewable energy, including
offshore wind power. It will serve as afront runner when Japan aims toachieve carbon neutrality by 2050.
Since renewable energy depends on
the weather conditions, it requires arobust grid capable of coping with
supply fluctuations. If interconnectors
further expand in the future, Hokkaido
will not just receive electric powerfrom Mainland Japan throughinterchange; the electric powerbusiness to transmit renewable energy
generated in Hokkaido to Mainland
Japan will be further accelerated,” said
Fukushima.
The New Hokkaido-Honshu HVDC
Link is considered to have been a big
step forward to achieve a scheme ofconnecting all of Japan through a large
grid and sending electricity, which is
generated at various locations and byvarious methods, to the consumption
areas. Abe, who currently promotes anoffshore wind power generation
project in Japan, talked about his
aspiration regarding the future of DC
XLPE cables.
“To promote the widespread use ofrenewable energy, whose power
generation amount is unstable, largearea interconnection must be ensured
to stabilize the supply amount. The DC
XLPE cables will increase theirpresence in interconnector projects inand outside Japan. I hope to gain
experience and knowledge overseas
and meet the growing demand inJapan,” said Abe.
In the paradigm shift in the history ofenergy, Sumitomo Electric will fulfill its
role as a supporter of electric powercompanies by offering DC XLPE
cables.

09

■ Installation route of the NEMO Link

The true value of DC XLPE cableproven in Europe
In Europe, which has been a global
leader in tackling climate change,
cross-border trade of electricity isalready commonplace, and there is aninternational power transmission line
using Sumitomo Electric high-voltage
direct current (HVDC) cable.
The UK-Belgium interconnector was
built to help reduce CO2 emissions byutilizing renewable energy generated
in both countries and to facilitate
low-cost and stable powerinterconnection. In 2015, Sumitomo
Electric signed a contract for thisproject with Nemo Link Limited, a joint
venture between National Grid plc (UK)and Elia (Belgium), and took its firststep into the European interconnector
market. Sumitomo Electric was
responsible for the manufacturing andinstallation of DC XLPE cable of a total
length of approximately 140 km,
including a submarine section of 130
km across the North Sea. Theinterconnector went into operation in
February 2019, and its transmission
voltage of 400 kV set a world record
at that time. While the first issue of thise-magazine featured a story about
receiving the order for this project, thisissue introduces a story after that tothe present.
The offshore installation started fromthe UK side in August 2017. The entire
construction process had to becompleted by the early winter of 2019
in order to start operating the facility
as scheduled. To meet the tightschedule, Sumitomo Electric sent
engineers with a wealth of experience.
One of them is Takuya Miyazaki(Submarine Construction Group,
Offshore Projects Construction
Department, Power Cable Project
Division), who directed theconstruction at the site as a memberof the construction team.
“About 50% of troubles occur in theprocess of connecting cables. However,as long as they relate to connecting,

10

Takuya Miyazaki
Senioir Assistant Genral Manager,
Submarine Construction Group, Offshore Projects
Construction Dept., Power Cable Project Div.

Cable laying on the Belgium beach side

Nemo Link interconnector cables to be installed
between UK and Belgium (before cable burial)

we know how to manage them. This is
our strength since we haveaccumulated a wealth of know-how.
However, at the late stage of theconstruction, when it seemed to beproceeding as scheduled, an
unexpected problem occurred. The
cable installation work stopped 3 km
before the cable landing point on the
Belgium side. The planned landing
point was a swimming beach. Since it
was difficult for a large submarine
cable laying ship to navigate theshallow sea, a special construction
method and work ships that suit theterrain were necessary, but apparently
the work method taken by theconstruction company in charge of thisprocess was wrong,” says Miyazaki.

“The cable cannot be landed!”—A
decision made to resolve the situation
It was a different kind of problem
from the ones that had been able to beresolved by patiently dealing withthem. While taking time to consider
countermeasures, report the situation
to Nemo Link, and discuss responsewith related departments in Japan, theswimming season came. On-site work
was not possible during the season,and the time left for the construction
team was becoming shorter andshorter. The testing of the cable had tobe completed by early December,when the testing of the converter
station was scheduled to begin. A
tense atmosphere pervaded the team.
“A construction delay crossed mymind,” reveals Miyazaki.

An Excellent Operation
Rate of 99.8% Achievedby a Multinational Team– Nemo L ink Project –“In the end, we hastily arranged
another construction company andtried landing operation several times
by changing cable-laying ships. It wasa tightrope walk, but the landing was
finally completed in October 2018,”
says Miyazaki.
However, some European membersof the construction team disagreed
with this response.
“In Europe, if a contract is not
fulfilled by a subcontractor, it seems to
be common to prioritize negotiation
over anything else, and people thinkthat it is unavoidable to suspend theconstruction during the negotiationand delay the schedule. However, weprioritized keeping the delivery
schedule promised to Nemo Link andtried to solve the problem withoutsuspending the construction. We gave
top priority to doing what we should
do for our customer. This Japanesestyle ‘customer-first principle’ may
have seemed strange to European
members,” says Miyazaki.
Miyazaki and his Japanesecolleagues sincerely explained the“Sumitomo Electric way” to European
members. Although they had different
ideas and methods from each other,
they shared professionalism and acommon desire for the success of the
project.
“The construction team consisted oftwenty-some European members,
mainly from the UK and Belgium, andthree to four Japanese members. It
may be more accurate to say thatJapanese members acted as‘coordinators’ who created an

Landing operation of the submarine cable on the Belgium side

environment in which individual teammembers could perform their jobs at ahigh level, rather than ‘instructors’ or‘leaders.’ Since we had built a
relationship of trust with our European
counterparts while keeping this inmind, they finally accepted the way wesuggested,” says Miyazaki.

Transparency that strengthened thepartnership
The landing of the submarine cableon the Belgian side was the biggest
challenge for the project, but it
resulted in increased confidence in
Sumitomo Electric, says Mr. Bert Maes,
the CEO of Nemolink Ltd.
“It was a very risky decision tochange the subcontractor at the latestage of the construction, but
Japanese
members clearly
explained why
the problem hadoccurred and how
they were dealing
with it,” says Mr.
Maes.
When Nemo
Link wasestablished as a
joint venture
between the UK
and Belgium andbegan discussing
the selection ofcontractors forthis project,
National Grid was
reluctant to
Mr. Bert Maes,
CEO, Nemolink Ltd.

Construction proceeded with multinational members

appoint a company that had not had
any track record in Europe, while Elia
was willing to use DC XLPE cable. An
opportunity to resolve thedisagreement between the twocompanies was the enthusiastic
proposal from Sumitomo Electric:“Please visit Japan to see ourmanufacturing site.”“We decided to leave the submarine
section to Sumitomo Electric because
we were convinced of its transparency
in the event of a problem, not tomention its technical excellence,” says
Mr. Maes.
He says that the final deciding factor
was that Sumitomo Electric showed
things as they were without hiding or
exaggerating.
“This attitude was consistentthroughout all processes, frommanufacture to transportationand construction. Sumitomo
Electric also showed greatcooperation with Siemens
Energy, a German company incharge of the converter
station,” says Mr. Maes.

contributor to the success of thisproject.
“The cable was not the only thingthat was connected through thisproject,” says Mr. Joergen Kroemeke,
General Manager of HVDC Project
Execution at Siemens Energy, referring
to another aspect of the project.
“The construction team was amultinational organization withmembers from five countries. Not only
Japan and Europe, but also individual
European countries have different
backgrounds. A strong partnership was
essential to achieve a common goal,
and it was a challenge to find how tobuild it. Team members actively
interacted with each other even during
non-work hours by going on weekend
trips with their families and going out
for dinner. It was an invaluable
opportunity to deepen our
understanding of each other’s culture,”says Mr. Kroemeke.
The success of this projectsignificantly strengthened therelationship between the twocompanies. Since then, as reliable
partners, they have jointly worked ontechnical development andparticipated in various interconnection
projects around the world.
In 2022, the UK-Belgium
interconnector celebrated its fourthyear of operation. With the tailwind of
the increasing development of offshore
wind farms, it is playing an importantrole in power infrastructure in the EU.
Due to the impact of the COVID-19
pandemic, the members of Sumitomo
Electric have had to abandon visiting
the site to perform regular inspectionsin 2020. However, this winter, theyreceived good news from Nemo Link:“The annual facility operation rate in
2021 was 99.8%, the highest in the past
three years!” Such a high average alsomeans Nemo Link's stable earnings
from the facility. Sumitomo Electric DC
XLPE cable is certainly demonstrating
its true value in an environmentallyadvanced region.

Great achievement of a
99.8% facility operation rate
While Sumitomo Electric
was in charge of the HVDC
cable, Siemens Energy was incharge of the converter
station that converts
transferred electricity fromDC to AC and vice versa. The
partnership between thesetwo companies was a great

Strong partnership between Siemens and Sumitomo Electric
Left: Mr. Joergen Kroemeke, General Manager of HVDC Project
Execution, Siemens Energy Global GmbH & Co. KG
Right: Teruaki Kawaguchi, Project Director, Sumitomo Electric11

■ Sumitomo Electric’s track record in winning contracts and instal ling DC XLPE cables (as of April 2022)
U.K.-Belgium interconnector (±400 kV)
Renewable energy and DC powertransmission cables
Just like two wheels of a cart toward
decarbonization

NEMO project:
Awarded a contract in 2015, completed in 2019
World’s highest voltage DC XLPE cables at
DC 400-kV in commercial operation
Entry into the European interconnector market
as the first Asian cable manufacturer

Extra-high voltage DC power transmission cablesystem in Germany (±525 kV)
A-Nord project:
Awarded in 2020, to be completed in 2028
World’s highest voltage DC XLPE cables under construction

Germany-Denmark interconnector (±400 kV)
KONTEK: Awarded in 2021, to be completed in 2023
World’s first system adopted with the combination of Line
Commutated Converters and 400-kV-class DC XLPE cables

First extra-high voltage DC XLPE
cables to be used in the Middle EastAwarded in 2009, completed in 2012
World’s highest voltage DC XLPE
cables as of 2012

New Hokkaido-Honshu HVDC Link(+250 kV)

Extra-high voltage DC power transmission
system in UAE (±400 kV)
Project Lightning: Awarded in
2022, to be completed in 2025

Hokkaido-Honshu HVDC Link(±250 kV)

Extra-high voltage DC power transmission cablesystem in India (±320 kV)
PK2000:Awarded in 2017, completed in 2021
First extra-high voltage DC powertransmission cables in India

Hokuto-Imabetsu DC Trunk Power Line:Awarded in 2015, completed in 2019
World’s longest extra-high voltage
cables installed in a subsea tunnel
across a strait

Electricity is supplied whileconstantly balancing the power
generation amount with consumption.
Supply must not be lower thandemand, but oversupply must also be
avoided. Stable supply is maintained
when a necessary and sufficientamount of electricity is generated.
These are the unique characteristics ofthis energy.
This is why renewable energy, whose
power generation amount depends on
the weather conditions, poses
difficulties. Power generation andconsumption in a region inevitably
results in unstable electric power
supply. However, if many power
generation systems are linked via aninterconnected grid in a large area tosecure a large supply amount, thesurplus electricity in a consumption
area can be delivered to a different
consumption area where electricity isin short supply. In addition, renewable
power plants, including offshore windfarms, are located in remote areas. For
these reasons, HVDC cables that canwithstand large-capacity long-distancepower transmission are definitely
required to realize a decarbonizedsociety.
In Europe, a project is underway tobuild an offshore wind power
generation facility called “energy
island” in the North Sea and the Baltic
Sea and share electric power withneighboring countries. Obviously, DCinterconnectors will be reinforced, andthe international grid will be further
expanded.
Renewable energy and DC powertransmission cables are just like twowheels of a cart to lead the world tocarbon neutrality.

neutrality, where the global community
is linked by interconnectors, is getting
closer to reality.
Yasuyuki Shibata, Managing
Executive Officer and General Managerof the Social Infrastructure Sales &Marketing Unit, who supervised various
interconnector projects in and outside
Japan, talked about the pride of amanufacturer in a growing market
toward a decarbonized society.
“Realization of a decarbonizedsociety is an imminent issue.
Manufacturers, including Sumitomo
Electric, can resolve issues by offering
technologies and products. Notably,
DC power transmission cables areindispensable to promote thewidespread use of renewable energy.
Our DC XLPE cables were derived
from about 30 years of perseveringresearch and in-house development
based on materials technology. This isan unparalleled product that embodies
our identity. It is my greatest pride tounderpin our society by harnessing thistechnology,” said Shibata.
Shibata continued to express his
commitment to carbon neutrality withenthusiasm.
“We will work on carbon neutrality
based on the belief that we will achieve
it. We will continue to further improve
the quality of products and expand
production facilities. We hope toestablish a reputation in the global
market by taking full advantage of ourexpertise and contributing directly to a
decarbonized society,” said Shibata.
As a key player in the global arena,
Sumitomo Electric has already been
taking on challenges to deliver as
many DC XLPE cables as possible andlead the world to a sustainable future.

Mission as a specialist of DC powertransmission cables

U.K.-Ireland interconnector (±320 kV)
Greenlink project:
Awarded in 2021, to be completed in 2024
Load leveling through interchange of renewableenergy between countries

Such a project is not limited toEurope. In COP26, India, which had not
mentioned any specific numericaltarget, announced that it would
increase the percentage of renewableenergy to 50% by 2030. In India, aninterconnector for which Sumitomo
Electric manufactured and installed, an
HVDC XLPE cable of ±320 kV went
into operation in 2021. Multiple projects
are underway in various parts of theworld to newly install and expand
interconnectors. The number ofinquiries that Sumitomo Electric
receives has been increasing year afteryear. The advent of the era of carbon

By Crossing Borders, HVDC XLPE Cable
Brings the Future of Electricity to People Around the World.
12

Yasuyuki Shibata
Managing Executive Officer and General Manager of
the Social Infrastructure Sales & Marketing Unit

13

Sumitomo Electric
The Professionals
Makoto Katayama
Deputy General Manager of the R&D Planning & Administrative Div. andGeneral Manager of the Planning Dept.

Featured person

1 9 9 3 : Joined Sumitomo Electric
1 9 9 3 : Electromagnetic Application System Research Dept., ElectricPower System Technology Laboratory
1 9 9 3 : Harima Laboratory
2000: Optical Communication Research Dept., Yokohama Laboratory
2005: Director of the Optical Precision Implementation Group,
Optical Components R & D Dept., Optical Communications
R & D Labs. and Photonics Analysis Group of the Analysis
Technology Research Center
2008: R & D Planning Dept.
2009: President of Innovation Core SEI, Inc. (U.S.)
2 0 1 6 : Manager of the Innovation Promotion Office, R & D Planning &Administrative Div.
2 0 1 9 : General Manager of the Planning Dept., R & D Planning &Administrative Div.
2 0 2 1 : Deputy General Manager of the R&D Planning & Administrative
Div. and General Manager of the Planning Dept.

“Favorable terrain is more important
than good timing, Harmony amongpeople is more important thanfavorable terrain” – I have been
following this teaching.
“Harmony among people” to me,
does not mean a group of playful goodfriends, but means a situation whereindividuals have motivation and belief
and continue to improve themselves
while working toward a shared vision.

Building a Shared Vision toCreate “1” from “0”“Talking with Unfamiliar People and Organizations”
This is the Way to Open Up New Businesses.
What to do to overcome fear
“Sumitomo Electric will establish anorganization to conduct research onindustrial applications of synchrotron
radiation. Would you like to join it?” If asenior researcher of my university
laboratory had not invited me, I would
have chosen a career as a scientist. To
tell the truth, while I was conducting
research on nuclear fusion in mydoctoral program, I was secretly
envious of former fellow students frommy master’s program, who had been
hired by corporations. Although they
complained about their difficulties, butthey talked about their work withexcitement. I decided to join
Sumitomo Electric because I wasstrongly motivated to contribute tosociety in a more direct way.
When I was assigned to the Harima
Laboratory, I was immediately put incharge of the process from planning todesign to completion of a beamline.*¹
This was exactly what I heard before
I joined the company: “Sumitomo
Electric has a corporate culture thatallows young employees to undertakeprojects with a sense of responsibility.”
Subsequently, I undertook a project toprepare to promote the utilization ofSPring-8.*² I learned what “goaloriented basic research” means at acompany. At the Harima Laboratory,
we worked on commercializing yet-tobe-publicized research results andcontribute to society. Namely, we were
working every day to find a way tocreate “1” from “0”. Researchers
dedicated their effort to gathering
information to come up with new
ideas. I also read many business books.
At that time, I came across the “fact,
faith, and fear” theory of future insight.
Here, “fear” means that one is not evenaware of what he or she does not
know. To start something new, it wasnecessary to overcome fear. By talking
with unfamiliar people andorganizations, I think I could overcome
the fear of what I don’t know. I wasconvinced that this was the answer tocreating something out of nothing.
However, I was not expecting I would
learn just how difficult it was, years
later.
*1: Beamline: Equipment for using synchrotron
radiation*2: SPring-8: Large synchrotron radiation facilityof the highest performance in the world capableof generating synchrotron radiation located in
Harima Science Garden City in Hyogo, Japan

Melancholic Fridays in Silicon Valley
Later, I was put in charge of thedevelopment of optical parts at the
Yokohama Laboratory. In 2008, I was
assigned to the R&D Planning Division.
In the spring of 2009,14

I received an offer to be transferred toInnovation Core SEI, Inc. (ICS) in the
U.S. The mission was to explore new
business opportunities in Silicon Valley,
the test bed of the global market. This
was the “business to promote PoC
business,” which
I proposed in a project under directsupervision of the president, to think
about the future of Sumitomo Electric
30 years later. Honestly, I had not
expected to be assigned this mission
myself.

One year after returning to Japan, I visited the ICS
office on a business trip and met Millard, one of mycolleagues, again on Casual Friday.

Immediately after I was transferred
to ICS, I worked on a project to enter
the development of Light Peak, thenext-generation communication
protocol (later renamed“Thunderbolt”), which was to be used
between digital electric home
appliances, such as PCs and TVs, under
the initiative of Intel. At first, the Intel
staff did not even remember ourcompany name and called us“Sumimoto.” Nevertheless, I made an
appointment in the afternoon every
Friday and visited them with our sales
team to discuss topics that wemanaged to come up with. We
continued this routine for months.
Sometimes, we could not see the Intel
staff when we paid a visit because
their working style was very casual on
Fridays. I was only motivated tocontinue visiting them because I had
determined to do so. I never felt somelancholic as I did on Fridays.
One day, we learned that they had aproblem with a newly developed
product. We proposed on the spot tostudy solutions. I asked for help fromthe Optical Communications R&D Lab,
with which I was once affiliated. We
were able to propose a solution in lessthan two weeks. In response, they
introduced several Intel researchers,
and we were able to build a good

relationship. Our proposal to resolve
the problem of twisted wires by using
ultra-fine coaxial wires was also wellreceived. Sumitomo Electric waschosen to be the first vendor for the
project. This was possible because of
the comprehensive capabilities of theSumitomo Electric Group, which hasvarious technology seeds and enables
prompt collaboration among relevant
departments to take action.

“Harmony among people” to achievea shared vision
I also made it a personal rule toparticipate in networking events on
Fridays. Silicon Valley was uniquely
vibrant even after Lehman Brothers
collapsed. Events were held at different
locations, and engineers who just met
exchanged information off-the-record
over drinks. This was a common
practice. I am shy around strangers, so
I felt blue until I reached the venues.
Once I drink, I become talkative, so
I enjoyed the events.
At that time, Tech Giants, which later
became known as GAFA (Google,
Apple, Facebook, and Amazon), wererapidly growing by acquiring start-ups.
They employed many engineers from
India and China. On a public road in
San Jose, I saw a company conducting
an automated driving test. This waswhat is called proof of concept (PoC)
today, which is the initial phase of a
new business. This was exactly what
we were trying to do to overcome“fear.” We practiced the solution tocreate something out of nothing in
Silicon Valley without knowing it. We
went out to see people, talked about
our vision, and seriously asked forcandid opinions. The starting point wascommunication with unfamiliar people
and organizations.
I learned an old saying from myuniversity professor: “Favorable terrain
is more important than good timing,
Harmony among people is more
important than favorable terrain.”*³ I
have been following this teaching.
“Harmony among people” to me,
does not mean a group of playful goodfriends, but means a situation whereindividuals have motivation and belief
and continue to improve themselves
while working toward a shared vision.
To achieve sustainable growth of
Sumitomo Electric, “Harmony amongpeople,” whereby highly capable
individuals work toward a sharedvision, will play a key role. Such activity
will help create new businesses.
*3: A quote from Mencius. In order of worthinessof consideration when planning an operation, fromleast to most, are timing, terrain, and Harmony
among people.

15

A Picture of Sumitomo Electric in Those Days

2010

Commencement of Sales of Aluminum Wiring Harnesses

Wiring harnesses that are arranged throughout a vehicle

Efforts to Resolve Social and Global Issues
In 2010, Sumitomo Electric launched sales of aluminum
automotive wiring harnesses. A wiring harness refers toan assembly of electric wires for power supply andsignal transmission. In line with the increasing
functionality of vehicles, the number of electronic
devices built into vehicles has been increasing. Wiring
harnesses connect these devices to supply electricity
and transmit signals throughout a vehicle.
The Sumitomo Electric Group started the development
and production of wiring harnesses immediately after
the end of WWII. In the 1960s, the Company rapidly
expanded production due to the high economic growth
period of Japan and resultant motorization.
Recently, the auto industry has been working to
reduce energy consumption and improve fuel efficiency
in order to cut CO2 emissions, which has become a socialand global issue. It was essential to reduce the weight ofthe vehicle body in line with the improvement of engine
combustion efficiency. In general, copper electric wires
are used for wiring harnesses due to their superb
conductivity. To meet the needs of reducing the weightof the vehicle body, the Sumitomo Electric Group

18

vol.

Information and videos not posted in this magazine
are found on the "id" special site

https://global-sei.com/id/

developed aluminum alloy electric wires exclusively for
automotive use by achieving high strength andconductivity. It succeeded in halving the weight while
maintaining current-carrying capacity equivalent to thatof copper electric wires. When the product was released
in 2010, the anti-vibration performance was inferior tothat of copper electric wires. The scope of application
was limited to interior wiring, such as doors, andinstrument panel wiring around the driver’s seat.
In 2015, the Sumitomo Electric Group succeeded in thedevelopment of high-strength aluminum alloy electric
wires, whose strength was superior to that of copper
electric wires, by taking full advantage of its engineering
capabilities. This made it possible to use aluminum wiring
harnesses in areas subject to severe vibration, including
the area around the engine. Aluminum wiring harnesses
contribute to weight reduction and resource
conservation because the reserves of aluminum areseveral times larger than that of copper.
. Also read id vol. 02 feature article: “Aluminum Wiring Harness: Key
Factor in Change of Automobiles and Auto Future.”https://global-sei.com/id/2017/10/pdf/sei_id002.pdf

Issue: Summer 2022
Publisher: Sumitomo Electric Industries, Ltd.
(Public Relations Department)
4-5-33, Kitahama, Chuo-ku, Osaka, Japan
Publisher in charge: Yuichiro Horiba
Editor: Universal Combo Inc.