November 11th to 15th 2007 - The 20TH World Energy Congress & Exhibition, Rome , Italy
Prospects of Smart Grid Technologies for a Sustainable
and Secure Power Supply
W. Breuer, D. Povh, D. Retzmann*, Ch. Urbanke, M. Weinhold
Siemens, Germany
ABSTRACT
Deregulation and privatization are posing new challenges on high voltage transmission and on
distributions systems as well. System elements are loaded up to their thermal limits, and power trading
with fast varying load patterns is contributing to an increasing congestion. In addition to this, the
dramatic global climate developments demand for changes in the way electricity is supplied.
Environmental sustainability and security of power supply are the goals for future grid developments.
Estimated global investments required in the energy sector until 2030 are $16 trillion, according to
IEA statistics. In Europe alone, some € 500 billion worth of investment will be needed to upgrade the
electricity transmission and distribution infrastructure [1]. The electricity network of the future must
be secure, cost-effective and environmentally compatible.
KEY WORDS:
Security and Environmental Sustainability of Supply; Smart Grid Technologies; Elimination of
Bottlenecks in Transmission; Blackout Prevention; Increase in Transmission Capacity; Reduction in
Transmission Losses; Enhanced Grid Access for Regenerative Energy Sources (RES)
1. INTRODUCTION
The vision and enhancement strategy for the future electricity networks is depicted in the program for
“SmartGrids”, which was developed within the European Technology Platform (ETP) of the EU in its
preparation of 7th Frame Work Program.
*dietmar.retzmann@siemens.com
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Features of a future “SmartGrid” such as this can be outlined as follows [1]:
•
Flexible: fulfilling customers’ needs whilst responding to the changes and challenges ahead
•
Accessible: granting connection access to all network users, particularly for RES and high
efficiency local generation with zero or low carbon emissions
•
Reliable: assuring and improving security and quality of supply
•
Economic: providing best value through innovation, efficient energy management and ‘level
playing field’ competition and regulation
It is worthwhile mentioning that the Smart Grid vision is in the same way applicable to the system
developments in other regions of the world. Smart Grids will help achieve a sustainable development.
Links will be strengthened across Europe and with other countries where different but complementary
renewable resources are to be found. For the interconnections, innovative solutions to avoid
congestion and to improve stability will be essential. HVDC (High Voltage Direct Current) provides
the necessary features to avoid technical problems in the power systems. It also increases the
transmission capacity and system stability very efficiently and helps prevent cascading disturbances.
HVDC can also be applied as a hybrid AC-DC solution in synchronous AC systems either as a Backto-Back for grid power flow control (elimination of congestion and loop flows) or as a long-distance
point-to-point transmission.
An increasingly liberalized market will encourage trading opportunities to be identified and developed.
Smart Grids is a necessary response to the environmental, social and political demands placed on
energy supply [1].
In what follows, the global trends in power markets and the prospects of system developments are
depicted, and the outlook for Smart Grid technologies for environmental sustainability and system
security is given.
2. GLOBAL TRENDS IN POWER MARKETS
In the nearest future we will have to face two mega-trends. One of them is the demographic change.
The population development in the world runs asymmetrically. On the one hand, a dramatic growth of
population is to be seen in developing and emerging countries. On the other hand, the population in
highly developed countries is stagnating. Despite these differences, the expectancy of life increases
everywhere.
This increase in population (the number of elderly people in particular) poses great challenges to the
worldwide infrastructure. Water, power supply, health service, mobility – these are only some of the
notions which cross one’s mind directly.
The second mega-trend to be mentioned is the urbanization with its dramatic growth worldwide. In
less than two years more people will be living in cities than in the country. Megacities keep on
growing. Already today they are the driving force of the world’s economy: Tokyo e.g. is the largest
city in the world, its population is 35 m people and it is responsible for over 40 % of the Japanese
economic performance. Another example is Los Angeles with its 16 m citizens and a share of 11 % in
the US-economy; or Paris with its 10 m citizens and 30 % of the French gross domestic product.
Both of these mega-trends make the demand for worldwide infrastructure grow. Fig. 1 depicts the
development of world population and power consumption up to 2020. The figure shows that
particularly in developing and emerging countries the increase is lopsided. Fig. 2 highlights these
phenomenal developments in China’s megacity Shanghai.
This development goes hand in hand with a continuous reduction in non-renewable energy resources.
The resources of conventional as well as non-conventional oil are gradually coming to an end. Other
energy sources are also running short, ref. to Fig. 3. So, the challenge is as follows: for the needs of a
dramatically growing world population with the simultaneous reduction in fossil power sources, a
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proper way must be found to provide reliable and clean power. This must be done in the most
economical way, for a lot of economies, in the emerging regions in particular, cannot afford expensive
environmentally compatible technologies.
7.5 Billion
World Population
27,000 TWh
Power Consumption
6.1 Billion
4.4 Billion
45%
15,400 TWh
Developing and newly
Industrialized Countries
29%
8,300 TWh
15%
71%
85%
1980
Industrialized Countries
(OECD), CIS, Eastern
Europe
55%
2020
2000
Sources: IEA, UN, Siemens PG GS4 - 2006
Fig. 1: Development of World Population and Power Consumption - 1980 to 2020
Financial District Pudong, Shanghai
1989
Today
Fig. 2: Development of Megacities – Example Shanghai, China
Lifetime assuming
static Consumption
Lifetime (proven Reserves)
Lifetime (Reserves + Resources)
Conventional Oil
45 years
70 years
Non-conventional Oil
20 y.
30-80 years
Conventional Gas
65 years
150 years
Non conventional Gas
0 years
600 years
Coal
200 years
1300 years
Uranium
100 years
>1000 years with recycling
Sources: IEA, UN, Siemens PG GS4 - 2006
Fig. 3: Decreasing Energy Resources
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Consequently, we have to deal with an area of conflicts between reliability of supply, environmental
sustainability as well as economic efficiency [10]. The combination of these three tasks can be solved
with the help of ideas, intelligent solutions as well as innovative technologies, which is the today’s and
tomorrow’s challenge for the planning engineers worldwide.
This is exactly what Siemens has been doing over the last 160 years. In the field of power supply, the
founder of the company, Werner von Siemens, launched the electrical engineering with his invention
of the dynamo-electric principle in 1866. Since that time electric power supply has established itself
on all the continents, however, with an unequal degree of distribution. Depending on the degree of
development and power consumption, different regions have very different system requirements, ref.
to Fig. 4.
Use of new Technologies
Right of Way Problems, Transmission Bottlenecks
Power Consumption
per Capita
Least-Cost
Planning
High Energy Imports
Decentralized Power Supplies
More Investments in Distribution
Lifetime Extension, Monitoring
Increased Automation
Demand for Power Quality
System Interconnections
Long - Distance
Transmission
(FACTS, HVDC)
Introduction of
higher Voltage
Levels
Isolated small
Grids
Developing Countries
High Investments in Transmission Systems
Emerging Countries
Industrialized Countries
Fig. 4: Development of Power Consumption and System Requirements
In developing countries, the main task is to provide local power supply, e.g. by means of developing
small isolated networks.
Emerging countries have a dramatic growth of power demand. Enormous amounts of power must be
transmitted to large industrial regions, partly over long distances, that is, from large hydro power
plants upcountry to coastal regions which involves high investments. The demand for power is
growing as well. Higher voltage levels are needed, as well as long-distance transmission by means of
FACTS and HVDC.
During the transition, the newly industrialized countries need energy automation, life-time extension
of the system components, such as transformers and substations. Higher investments in distribution
systems are essential as well. Decentralized power supplies, e.g. wind farms, are coming up.
Industrialized countries in their turn have to struggle against transmission bottlenecks, caused, among
other factors, by increase in power trading. At the same time, the demand for a high reliability of
power supply, high power quality and, last but not least, clean energy increase in these countries. In
spite of all the different requirements one challenge remains the same for all: sustainability of power
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supply must be provided. Our resources on the Earth are limited, as shown in Fig.3, and the global
climate is very sensitive to environmental influences. The global industrialization with its ongoing
CO2 production is causing dramatic changes in the climate developments, ref. to Fig. 5.
Carbon Dioxide Variations in the Air
400
CO2
Concentration
(ppmv)
The Industrial Revolution has
caused a dramatic Rise in CO2
350
300
A crucial Global
Issue: to achieve
CO2 Reduction
250
200
Ice Age
Würm / Weichsel
0
100
Thousands
of Years ago
Mindel / Elster
Riß / Saale
200
300
400
Sources: Wikipedia, Siemens PTD TI, 2006
Fig. 5: CO2 Increase due to Human Influence is much higher than Natural Fluctuation
There is no ready-made solution to this problem. The situation in different countries and regions is too
complex. An appropriate approach is, however, obvious: power generation, transmission, distribution
and consumption must be organized efficiently.
The approach of the EU’s “SmartGrid” vision is an important step in the direction of environmental
sustainability of power supply, and new transmission technologies can effectively help reduce losses
and CO2 emissions.
3. PROSPECTS OF POWER SYSTEM DEVELOPMENT
The development of electric power supply began more than one hundred years ago. Residential areas
and neighboring establishments were at first supplied with DC via short lines. At the end of the 19th
century, AC transmission was introduced, using higher voltages to transmit power from remote power
stations to the consumers.
In Europe, 400 kV became the highest voltage level, in Far-East countries mostly 550 kV, and in
America 550 kV and 765 kV. The 1150 kV voltage level was anticipated in some countries in the past,
and some test lines have already been built. Fig. 6 and 7 depict these developments and prospects.
Due to an increased demand for energy and the construction of new generation plants, first built close
and then at remote locations from the load centers, the size and complexity of power systems all over
the world have grown. Power systems have been extended by applying interconnections to the
neighboring systems in order to achieve technical and economical advantages. Large systems covering
parts of or even whole continents, came into existence, to gain well known advantages, e.g. the
possibility to use larger and more economical power plants, reduction of reserve capacity in the
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systems, utilization of the most efficient energy resources, as well as achieving an increase in system
reliability.
However, some Countries
1600
kV
will finally “go” ≥ 1 GV
1400
6
1200
1000
5
800
600
400
2
1
200
4
3
EHV: 800 kV as “realistic” Standard
The “Initial” Statement
0
1900
1910
1920
1
2
3
4
5
6
1930
1940
1950
1960
1970
1980
1990
2000
Year
2010
110 kV Lauchhammer – Riesa / Germany (1911)
220 kV Brauweiler – Hoheneck / Germany (1929)
287 kV Boulder Dam – Los Angeles / USA (1932)
380 kV Harspranget – Halsberg / Sweden (1952)
735 kV Montreal – Manicouagan / Canada (1965)
1200 kV Ekibastuz – Kokchetav / USSR (1985)
Fig. 6: Development of AC Transmission – Milestones and Prospects
In the future of liberalized power markets, the following advantages will become even more important:
pooling large power generation stations, sharing spinning reserve and using most economic energy
resources, and considering ecological constraints, such as the use of large nuclear and hydro power
stations at suitable locations, solar energy from desert areas and embedding big offshore wind farms.
Examples of large AC interconnections are systems in North America, Brazil, China and India, as well
as in Europe (UCTE - installed capacity 530 GW) and Russia (IPS/UPS - 315 GW), which are planned
to be interconnected in the future.
ƒ
ƒ
1000 kV Line:
SIL = 4 GW
Transmission
of 6-10 GW is
feasible
ƒ
Voltage Levels of 735 kV to 765 kV AC were
introduced in the following Countries:
Canada, Brazil, Russia (USSR), South Africa,
South Korea, U.S.A. and Venezuela
UHV Transmission Lines (1,000 kV and above)
were built in Russia and Japan
ƒ Ekibastuz – Kokchetav (500 km)
ƒ Kokchetav – Kustanay (400 km)
ƒ Minami – Niigata / Nishi – Gunma (200 km)
ƒ Kita – Tochigi / Minami – Iwaki (250 km)
However, today these UHV Transmission Lines
are operated at 500 kV
Fig. 7: Development of EHV and UHV AC Transmission
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UCTE Synchronous Interconnections:
Δ f [mHz]
15
Frequency
5
Inter-Area Oscillations with Magnitudes up to
1000 MW

Damping Measures necessary
0
Spain
-100
Poland
-5

P [MW]
Frequency & Power
-200
-15
-25
-300
-35
(border
to France)
Germany
-45
(border to France)
Active Power France-Germany
-400
(one 400-kV
system)
-55
-65
-500
-75
-600
0
3
6
9
t [s]
15
12
Signals: simulated & measured by WAMS
… the 1st Step for
System Extension
The Interconnection
CENTREL to UCPTE
a)
1st UCTE Synchronous Zone
In synchronous Operation with 1st Zone
NORDEL
2nd UCTE Synchronous Zone
In synchronous Operation with 2nd Zone
b)
Zone 1 & 2 “resynchronized” since 10-10-2004 …
… since then, the Risk of
large Inter-Area Oscillations in
UCTE has been increased *
IPS/UPS
c)
UCTE - 1
* depending on
the actual Load
Flow Situation
UCTE - 2
Options for Grid
Interconnection
Turkey
AL MAGHREB
c)
Fig. 8: UCTE – Steps a) & b) for Interconnection of Zones 1, 2 and further Options c)
It is, however, a crucial issue that with an increasing size of the interconnected systems (ref. to Fig. 8),
the advantages diminish. There are both technical and economical limitations in the interconnection if
the energy has to be transmitted over extremely long distances through the interconnected
synchronous AC systems. These limitations are related to problems with low frequency inter-area
oscillations ([6], Fig. 8a), voltage quality and load flow. This is, for example, the case in the UCTE
system, where the 400 kV voltage level is in fact too low for large cross-border and inter-area power
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exchange. Bottlenecks are already spotted (Fig. 9, NTC values) and, for an increase in power transfer,
advanced solutions must be applied.
Bottlenecks
in the UCTE
System
NTC Values
for EastWest Power
Transfer
Source: UCTE - 5 / 2003
NTC = Net Transfer Capacity
Fig. 9: European Power Systems - Bottlenecks in UCTE
In deregulated markets, the loading of existing power systems will further increase, leading to
bottlenecks and reliability problems. System enhancement will be essential to balance the load flow
and to get more power out of the existing grid. Large blackouts in America and Europe confirmed
clearly that the favorable close electrical coupling of the neighboring systems might also include the
risk of uncontrollable cascading effects in large and heavily loaded synchronous AC systems [9].
System
G
System
A
System
B
System
C
System
D
System
E
System
F
Large
LargeSystem
SystemInterconnections,
Interconnections,using
usingHVDC
HVDCand FACTS
HVDC - Long Distance DC Transmission
HVDC B2B - via AC Lines
High Voltage AC Transmission & FACTS
DC – the Stability Booster and
“Firewall” against “Blackout”
“Countermeasures”
against large
Blackouts
Fig. 10: Large Power System Interconnections - Benefits of Hybrid Solutions
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Therefore, the strategies for the development of large power systems go clearly in the direction of
hybrid transmissions, consisting of DC and AC interconnections, including FACTS. Hybrid
interconnected systems such as these offer significant advantages, in terms of technology, cost savings
and reliability [9, 11, 12, 13, 19, 20].
Fig. 10 shows schematically a hybrid system with HVDC and FACTS. Power exchange in the
neighboring areas of interconnected systems can be achieved by means of AC links, preferably with
FACTS to increase transmission capacity and stability. The transmission of large power blocks over
long distances should, however, be realized by means of HVDC links directly to the locations of
power demand [12].
4. SECURITY OF SUPPLY – LESSONS LEARNED FROM THE BLACKOUTS
In Fig. 11, a summary of the US-Canada Blackout on August 14, 2003 is shown. In Fig. 11 a) a view
on the affected area is given and the satellite photos show the situation before and after the events. The
figure indicates that the Québec’s system in Canada was not affected due to its DC interconnections to
the US, whereas Ontario (synchronous interconnection) was fully “joining” the cascade. The reasons
why Québec “survived” the Blackout are very clear:
„
Québec´s major Interconnections to the affected Areas are DCLinks
„
These DC-Links are like a Firewall against Cascading Events
„
They split the System at the right Point on the right Time,
whenever required
„
Therefore, Québec was “saved”
„
Furthermore, the DCs assisted the US-System Restoration by
means of “Power Injection”
Fig. 11b) depicts the results of a study on the related transmission systems, published in May 2002. It
can be seen that load flow in the system is not well matching the design criteria, ref. to the “hot lines”,
shown in red color. In the upper right-hand corner of the figure, one of the later Blackout events with
“giant” loop flows is attached which occurred just in the same area under investigation one year
before.
Fig. 12 shows that the probability of large Blackouts is much higher than calculated by mathematical
modeling, particularly when the related amount of power outage is very large. The reasons for this
result are indicated in the figure. This means that, when once the cascading sequence is started, it is
mostly difficult or even impossible to stop it, unless the direct causes are eliminated by means of
investments into the grid and by an enhanced training of the system operators for better handling of
the emergency situations.
For these reasons, further Blackouts occurred in the same year. The largest was the Italian Blackout,
six weeks after the US-Canada events. It was initiated by a line trip in Switzerland. Reconnection of
the line after the fault was not possible due to a very large phase angle difference (about 60 degrees,
leading to blocking of the Synchro-Check device). 20 min later a second line tripped, followed by a
fast trip-sequence of all interconnecting lines to Italy due to overload. During this sequence, the
frequency in Italy ramped down for 47.5 Hz within 2.5 min, and the whole country blacked-out.
Several reasons were reported: wrong actions of the operators in Italy (insufficient load rejection) and
a very high power import from the neighboring countries in general. Indeed, during the night from
Saturday to Sunday, the scheduled power import was 6.4 GW - this is 24 % of the total consumption at
that time (27 GW; EURELECTRIC Task Force Final Report 06-2004). The real power import was
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even higher (6.7 GW; possibly due to the country-wide celebration of what is known as “White
Night”), ref. to Fig. 13.
Blackout: a large Area is out of Supply
Québec´s HVDCs assist
in Power Supply and
System Restoration
However, some Islands still have local Supply
Before the Blackout
a)
Source: EPRI 2003
*
System Enhancement necessary !
Source: ITC 8/2003 – “Blackout”
Source: National Transmission Grid Study; U.S. DOE
5/2002 – “Preview”
b)
* PTDF
Problems only in
the synchronous
interconnected
Systems
= Power Transfer Distribution Factor
Fig. 11: Blackouts 2003 - Example United States
a) The Blackout Area - and a Satellite View
b) Congestion and Loop Flows - Forecasting Studies and Cascading Events
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Fig. 12: Reasons for high Probability of Large Blackouts
... the Risk for a Spread of Disturbance
to UCTE was high
“Scheduled” Power Transfer from the Neighbors to Italy:
6.4 GW out of 27 GW * Consumption: 24 % is too high !
From “White Night” to
“Black Night”
Europe needs
Enhancements, too
Due to Country-Wide Celebrations of
the “White Night” in Italy, an increased
Power Import of 6.7 GW was observed
during Saturday Night, 9-27-2003
*Source: EURELECTRIC Task Force Final Report 06-2004
Fig. 13: Six Weeks after the US-Canada Blackout - a very large Blackout in Italy …
In Table 1, a summary of the root causes for the Italian Blackout is given. It can be concluded, that the
existing power systems from their topology are not designed for wide-area energy trading. The grids
are close to their limits. Restructuring will be essential, and the grids must achieve “Smart” features,
as stated before.
This is also confirmed by the recent large blackout on 4.11.2006 which affected eight EU countries
(Fig. 14). It has highlighted the fact that Continental Europe is already behaving in some respects as a
single power system, but with a network not designed accordingly. Europe's power system (including
its network infrastructure) has to be planned, built and operated for the consumers it will serve.
Identifying, planning and building this infrastructure in liberalized markets is an ongoing process that
requires regular monitoring and coordination between market actors [1].
The electric power supply is essential for life of a society, like the blood in the body. Without power
supply there are devastating consequences for daily life: breakdown of public transportation systems,
traffic jams, computer outages as well as standstill in factories, shopping malls, hospitals etc.
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Lessons Learned: Power Systems have not been designed for “wide-Area”
Energy Trading with daily varying load patterns
A Key-Issue in many Power Systems today:
Source:
UCTE Interim
Report 10-27-2003
The Grids
are “close
to their
Limits”
Table 1: Summary of Root Causes for the Italian Blackout and Action Plan
UCTE Interim Report 10-27-2003
Source:
Presented at CEPSI, 6-10 November, 2006, Mumbai - India
Fig. 14: European Power System Disturbance on 4th November 2006
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In Fig. 15, a conclusion on the today’s power system limitations is given and the solutions are
outlined.
Increased Use of
Distributed and
Renewable Energy
Resources
Need for more
Energy
Capacity Increase
and Bulk Tower
Transmission over
Long Distances
Urbanization
Scarcity of
Natural
Resources
Distribution within
congested
Areas/Mega-Cities
Environmental
Awareness
Goal: reliable,
flexible, safe and
secure Grids
Open Markets
Fig. 15: Challenges in Power Transmission and Distribution
5. USE OF SMART GRID TECHNOLOGIES FOR SYSTEM ENHANCEMENT AND
GRID INTERCONNECTION
In the second half of the last century, high power HVDC transmission technology was introduced,
offering new dimensions for long distance transmission. This development started with the
transmission of power in a range of a few hundred MW and was continuously increased. Transmission
ratings of 3 GW over large distances with only one bipolar DC line are state-of-the-art in many grids
today. World’s first 800 kV DC project in China has a transmission rating of 5 GW (ref. to section 6.)
and further projects with 6 GW or even higher are at the planning stage. In general, for transmission
distances above 700 km, DC transmission is more economical than AC transmission (≥ 1000 MW).
Power transmission of up to 600 - 800 MW over distances of about 300 km has already been achieved
with submarine cables, and cable transmission lengths of up to about 1,000 km are at the planning
stage. Due to these developments, HVDC became a mature and reliable technology [3, 12, 13]. During
the development of HVDC, different kinds of applications were carried out. They are shown
schematically in Fig. 16. The first commercial applications were HVDC sea cable transmissions,
because AC cable transmission over more than 80-120 km is technically not feasible due to reactive
power limitations. Then, long distance HVDC transmissions with overhead lines were built as they are
more economical than transmissions with AC lines. To interconnect systems operating at different
frequencies, Back-to-Back (B2B) schemes were applied. B2B converters can also be connected to long
AC lines (Fig. 16a). A further application of HVDC transmission which is very important for the
future is its integration into the complex interconnected AC system (Fig. 16c). The reasons for these
hybrid solutions are basically lower transmission costs as well as the possibility of bypassing heavily
loaded AC systems [12].
Typical configurations of HVDC are depicted in Fig. 17. The major benefit of the HVDC, both B2B
and LDT, is its incorporated ability of fault-current blocking which serves as an automatic firewall for
Blackout prevention in case of cascading events, which is not possible with synchronous AC links.
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Can be
connected
to long AC
Lines
a)
b)
a) Back-to-Back Solution
b) HVDC Long Distance Transmission
c) Integration of HVDC into the AC System
Hybrid Solution
c)
Fig. 16: Types of HVDC Transmissions
HVDC - High Voltage DC Transmission: It makes P flow
z HVDC “Classic” with LT Thyristors* (Line-commutated Converter)
z HVDC “Bulk” with 800 kV – for 5,000 MW to > 7,000 MW
z HVDC PLUS (Voltage-Sourced Converter – VSC)
800 kV for minimal Line
Transmission Losses
z HVDC can be combined with FACTS
z V-Control included
HVDC LDT - Long Distance Transmission
B2B - The Short Link
Back-to-Back Station
AC
AC
Submarine Cable Transmission
AC
AC
Long Distance OHL Transmission
AC
AC
DC Line
DC Cable
* LTT = Light-Triggered Thyristor with integrated Break-over Protection
Fig. 17: HVDC Configurations and Technologies
HVDC PLUS (Fig. 18) is the preferred technology for interconnection of islanded grids to the power
system, such as off-shore wind farms. This technology provides the “Black-Start” feature by means of
self-commutated voltage-sourced converters (VSC). Voltage-sourced converters do not need a
“driving” system voltage; they can build up a 3-phase AC voltage via the DC voltage at the cable end,
supplied from the converter at the main grid. Siemens uses an innovative Modular Multilevel
Converter (MMC) technology for HVDC PLUS with low switching frequencies. Therefore only small
or even nor filters are required at the AC side of the converter transformers. Fig. 18 summarizes the
advantages in a comprehensive way. The specific features of MMC are explained in details in [21].
Since the 1960s, Flexible AC Transmission Systems have been developed to a mature technology with
high power ratings [4, 5]. The technology, proven in various applications, became mature and highly
reliable. FACTS, based on power electronics, have been developed to improve the performance of
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weak AC Systems and to make long distance AC transmission feasible [4]. FACTS can also help solve
technical problems in the interconnected power systems. FACTS are applicable in parallel connection
(SVC, Static VAR Compensator - STATCOM, Static Synchronous Compensator), in series connection
(FSC, Fixed Series Compensation - TCSC/TPSC, Thyristor Controlled/Protected Series Compensation
- S³C, Solid-State Series Compensator), or in combination of both (UPFC, Unified Power Flow
Controller - CSC, Convertible Static Compensator) to control load flow and to improve dynamic
conditions. Fig. 19 and 20 show the basic configurations of FACTS.
¾ Low Switching Frequency
¾ Reduction in Losses
¾ Less Stresses
In Comparison with 2 and
3-Level Converter
Technologies
… with Advanced VSC Technology
= = =
= = =
~ ~ ~
~ ~ ~
= = =
= = =
Clean Energy to Platforms & Islands …
Fig. 18: DC with VSC – HVDC PLUS, the Power Link Universal System
FACTS - Flexible AC Transmission Systems: Support of Power Flow
z SVC – Static Var Compensator* (The Standard of Shunt Compensation)
z SVC PLUS (= STATCOM - Static Synchr. Compensator, with VSC)
z FSC – Fixed Series Compensation
and SCCL **
z TCSC – Thyristor Controlled Series Compensation*
for Shortz TPSC – Thyristor Protected Series Compensation**
Circuit Current
z GPFC – Grid Power Flow Controller* (FACTS-B2B)
Limitation
z UPFC – Unified Power Flow Controller (with VSC)
AC
AC
* with LT Thyristors
GPFC/UPFC
/ UPFC
FSC
SVC / STATCOM
AC
AC
/ TPSC
TCSC/TPSC
Fig. 19: Transmission Solutions with FACTS
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AC
AC
** with special High
Power LT Thyristors
„
„
„
„
Voltage Control
Reactive Power Control
Power Oscillation Damping
Unbalance Control (Option)
Benefits:
o Improvement of Voltage Quality
o Increased Stability
a)
Photo: 2 SVCs Pelham – SLD: 2 SVCs Harker – NGC, UK
~
~
TCSC/TPSC
α
FSC
Photo: TCSC & FSC, Kayenta, USA
b)
Controlled Series Compensation:
Fixed Series Compensation:

Increase in Transmission
Capacity
Mostly, a Combination
of both is used



Damping of Power Oscillations
Load-Flow Control
Mitigation of SSR
Fig. 20: Main FACTS Configurations (ref. to Text)
a) SVC for Parallel Compensation
b) TCSC/TPSC and FSC for Series Compensation
16/30
GPFC is a special DC back-to-back link, which is designed for fast power and voltage control at both
terminals [14]. In this manner, GPFC is a “FACTS B2B”, which is less complex and less expensive
than the UPFC.
Rating of SVCs can go up to 800 MVAr, series FACTS devices are installed on 550 and 735 kV levels
to increase the line transmission capacity up to several GW. Recent developments are the TPSC
(Thyristor Protected Series Compensation) and the Short-Circuit Current Limiter (SCCL), both
innovative solutions using special high power thyristor technology [14]. The world’s biggest FACTS
project with Series Compensation (TCSC/FSC) is at Purnea and Gorakhpur in India with a total rating
of 1.7 GVAr. Fig. 21 depicts the Siemens high power electronic applications worldwide. In the figure
the number and the expansion in large HVDC long-distance transmission projects are also indicated.
Lamar 2005
Virginia Smith 1988
Lugo 1985
3, 2 El Dorado
2006
2 Bellaire & Crosby 2008
Inez 1998
Spring Valley 1986
2 Dominion 2003
2 Marcy 2001-2003
Devers 2006
••
Nine Mile 2005
Dayton 2006
• •
• • •
•
•
•
•••••• • • ••
•
••• •• •
• ••
•• •
•
Porter 2006
Paul Sweet 1998
2 Adelanto 1995
2 Midway 2004
3 Vincent 2000
Clapham 1995,
Refurbishment
Military Highway 2000
2 Tecali 2002
Eddy County 1992
La Pila 1999
•
Nopala 2007
Cerro Gordo 1999
3 Juile 2002
.
Imperatriz 1999
Sinop 2007
Serra de Mesa 1999
… and over 115 Industry
SVCs all over the World
Status: 06-2007
In total:
over 170
SVCs
•
• •
• • ••
•
• • •
•
•
•
•
••
•
Fortaleza 1986
Milagres 1988
•
K.I. North 2004
Campina Grande 2000
Maputo 2003
Funil 2001
P. Dutra 1997
• •••
Illovo
Athene
Impala
Muldersvlei 1997
Load Flow
2 Hechi 2003
2, 2 Tian Guang 2003
3 Puti 2005
2 Gooty 2003
2 Cuddapah 2003
•
2 Sabah 2006
• •
Kapal 1994
•
•
1994-1995
Limpio 2003
2 Yangcheng 2000
Jember 1994
Barberton 2003
••
Parallel
.
Baish 2005 •
Samitah 2006
Iringa 2006
Shinyanga 2006
Bom Jesus da Lapa 2002
Series
2006
2 Fengjie 2006
•
•
•
••
• ••
•
Buzwagi 2007
Ibiuna 2002
•
2 Lucknow 2006
Ahafo 2006
Sao Luiz 2007
2, 2 Gorakhpur
2, 2 Purnea
Kanjin (Korea) 2002
2 Zem Zem 1983
•
1997
2 x 1.7 GVAr !
••
••
•
•
Laredo 2000 2 Benejama &
Seguin 1998 Saladas 2006
Kayenta 1992
5 North-South III, Lot B 2007
Acaray 1981
.
.•
Sullivan 1995 Dürnrohr 1983
Jacinto 2000 2 Hoya Morena &
Jijona 2004
Welsh 1995
Cano Limón 1997
Atacama 1999
Moyle MSC 2003
Brushy Hill 1988 Willington 1997
3 Montagnais 1993
Châteauguay 1984
Chinú 1998
Samambaia 2002
2 Pelham, 2 Harker &
2 Central, 1991-1994
Ghusais,
Hamria,
Mankhool,
Satwa
Etzenricht 1993
Wien Südost 1993
Radsted 2006
Siems 2004
Rejsby Hede 1997
9 Powerlink 2007,
Refurbishment
Nebo 2007,
Strathmore 2007
Refurbishment 2 Kemps Creek 1989
2 Greenbank & Southpine 2008
FSC
SVC
B2B/GPFC
NGH
MSC/R
UPFC
TPSC
STATCOM
CSC
Plus 21 Projects for
HVDC Long Distance
Transmission …
TCSC
Flicker STATCOM
11 x VSC
8 alone between 2000 &
2005 in 4 Continents
Fig. 21: FACTS & HVDC worldwide – Example Siemens (ref. to Text)
Bulk Power UHV AC and DC transmission schemes over distances of more than 2000 km are
currently under planning for the connection of various large hydropower stations in China [17, 18].
Ultra high DC (up to 800 kV) and ultra high AC (1000 kV) are the preferred voltage levels for these
applications to keep the transmission losses as low as possible.
In India, there are similar prospects for UHV DC as in China due to the large extension of the grid [15,
16]. The road-map for India’s hybrid bulk power grid developments is depicted in Fig._22. India’s
energy growth is about 8-9 % per annum, with an installed generation capacity of 124 GW in 2006 (92
GW peak load demand). The installed generation capacity is expected to increase to 333 GW by 2017
[20].
Fig. 23 depicts how the ideas of hybrid bulk power interconnections are reflected in China's UHV grid
developments [19]. The focus is on interconnection of 7 large inter-provincial grids of the Northern,
Central and Southern systems via three bulk power corridors which will built up a redundant
“backbone” for the whole grid. Each corridor is planned for about 20 GW transmission capacity which
shall be implemented with both AC and DC transmission lines with ratings of 4 - 10 GW each (at +/800_kV DC and 1000 kV AC, ref. to the figure). Therefore, each corridor will have a set-up with 2 - 3
17/30
systems for redundancy reasons. With these ideas, China envisages a total amount of about 900 GW
installed generation capacity by 2020. For comparison, UCTE and IPS/UPS together sum up to 850
GW today.
HVDC SYSTEMS BY 2011-12
NR
BHIWADI
DADRI
2500 MW
60 00 M
W
1500
MW
RIHAND
AGRA
500
MW
NER
BALIA
50 0
BISHWANATH
CHARIYALI
MW
SASARAM
ER
VINDHYACHAL
WR
CHANDRAPUR BHADRAVATI
1000
MW
• Back-to-Back: 6 x
TALCHER
(Σ 4,000 MW)
1500 MW
2X500MW
GAZUWAKA
PADGHE
0M
W
20
KOLAR
Main
Grid
HVDC BIPOLE
HVDC BACK-TO-BACK
Source: “Brazil-India-China Summit Meeting on
HVDC & Hybrid Systems – Planning and
Engineering Issues”, July 2006, Rio de Janeiro,
Brazil
SH
N&
ANDAMA
R
NICOBA
SR
K
LA
WE
AD
EP
a)
• Bipole : 6 x (Σ 13,500 MW)
LEGEND
MW
1 00
00
KOLHAPUR
DC
b) DEVELOPMENT OF CHICKEN NECK AREA
50 GW Hybrid:
EN
CHICK
NECK
AREA
≈ 10 GW AC
≈ 40 GW DC
EX
IS
10
Up t o
G
TIN
C
GW A
6 -7 x
VD
800 k
C
VD
800 k
RE
DC
C
VD
800 k
F UT U
6 GW
800 k
C
V DC
Fig. 22: Grid Developments in India [8, 9]
a) System Overview – including the “Chicken Neck Area”
b) Hybrid Solutions in the Chicken Neck – including UHV DC
18/30
Transmission
Capacity of
DC: 4-6 GW
each Corridor
will be 20 GW Solutions:
800 kV DC &
nx
in 2020 …
North Corridor
1000 kV AC
AC: 6-10 GW
3 x 20 GW
… the installed
Generation
Capacity will
be 900 GW
Central Corridor
Sources:
South Corridor
Fig. 23: Perspectives of Grid Developments in China - AC & DC Bulk Power
Transmission from West to East via three main Corridors
The benefits of hybrid power system interconnections as large as these are clear:
•
•
•
•
•
Increase in transmission distance and reduction in losses - with UHV
HVDC serves as stability booster and firewall against large blackouts
Use of the most economical energy resources - far from load centers
Sharing of loads and reserve capacity
Renewable energy resources, e.g. large wind farms and solar fields can be integrated much
more easily
However, with the 1000 kV AC lines there are also some stability constraints: if for example such an
AC line of this kind with up to 10 GW transmission capacity is lost during faults, large inter-area
oscillations might occur. For this reason, additional FACTS controllers for power oscillation damping
and stability support are in discussion.
The idea of embedding huge amounts of wind energy in the German grid by using HVDC, FACTS
and GIL (Gas Insulated Lines) is depicted in Fig. 24. The goal is a significant CO2 reduction through
the replacement of conventional energy sources by renewable energies, mainly offshore wind farms
[2]. Power output of wind generation can vary fast in a wide range, depending on the weather
conditions. Therefore, a sufficiently large amount of controlling power from the network is required to
substitute the positive or negative deviation of actual wind power infeed to the scheduled wind power
amount. Fig. 25 shows a typical example of the conditions, as measured in 2003. Wind power infeed
and the regional network load during a week of maximum load in the E.ON control area are plotted.
The relation between consumption and supply in this control area is illustrated in the figure. In the
northern areas of the German grid, the transmission capacity is already at its limits, especially during
times with low load and high wind power generation [7].
An efficient alternative for the connection of offshore wind farms is the integration of HVDC long
distance transmission links into the synchronous AC system as schematically shown in Fig. 26 [13].
19/30
AC or DC
Cables
Long-term: 30 - 50 GW
platform
incl.
Baltic Sea &
On-Shore
platform
Medium-term
Planning
GIL in Tunnel
to avoid 40-50
Cables nearby
the Coasts
2020
4 x GIL, 4 x SVC, 2 x HVDC
Source: DENA Study 02-24-2005
Fig. 24: Integration of large Offshore Wind Farms by means of
GIL, FACTS and HVDC - A Smart Grid Solution
This will be a strong Issue in the German Grid Development
„ Additional Reserve Capacity is
required
Problems with Wind Power Generation:
o Wind Generation varies strongly
o It can not follow the Load Requirements
Source: E.ON - 2003
Fig. 25: Network Load and aggregated Wind Power Generation during a Week of
maximum Load in the E.ON Grid
20/30
Long-term: 30 - 50 GW
Share in installed wind energy of 12,223 MW
Share in installed Wind Energy of
E. ON Netz:
E. ON Netz:
48 %
Vattenfall
Europe
Transmission:
Vattenfall
Europe
Transmission:
37 %
RWE
Net:
14 %
RWE
Transportnetz Strom:
EnBW
Transportnetze:
1%
EnBW Transportnetze:
Vattenfall
Europe Transmission
Source: E.ON -
12,223 MW
48 %
37 %
14 %
1%
2003
Benefits of such a Solution:
o Load Sharing
o Generation Reserve Sharing
Installed Generation Capacity: 120 GW (2006)
Fig. 26: Use of HVDC Long Distance Transmission for Wind Farm Grid Access
6. PROJECTS WITH HVDC AND FACTS – FOR ENVIRONMENTAL
SUSTAINABILITY AND SECURITY OF SUPPLY
6.1. Bulk Power DC Transmission in China
The 3000 MW +/-500kV bipolar Gui-Guang HVDC system (Fig. 27) with a transmission distance of
980 km was build to increase the transmission capacity from west to east [12]. It is integrated into the
large AC interconnected system. In the same system there is also an already existing HVDC scheme in
operation. Both DC systems operate in parallel with AC transmission in this grid.
2004
View of the Thyristor-Module
Rating:
Voltage:
3000 MW
± 500 kV
Contract: Nov. 1, 2001
terminated 66 Months
Months
Project completed
ahead of Schedule by Sept. 2004
Fig. 27: Highlights of the GuiGuang HVDC Transmission
Project
Thyristor: 5" LTT with integrated
Overvoltage Protection
21/30
In addition to this, Fixed Series Compensation (FSC) and Thyristor Controlled Series Compensation
were used in the system. Due to long transmission distances, the system experiences severe power
oscillations after faults, close to the stability limits. With its ability to damp power oscillations, HVDC
plays an important role for reliable operation of the system [13].
In June 2007, Siemens received the order from China Southern Power Grid Company, Guangzhou, to
construct a high-voltage DC transmission (HVDC) system between the province of Yunnan in the
southwest of China and the province of Guangdong on the south coast of the country together with the
Chinese partners. The system will be the first in the world to transmit electricity at a DC voltage of +/800 kV. At the same time, this project with a power transmission capacity of 5000 MW will be the
long-distance HVDC link with the world’s highest power capacity which has ever been achieved. The
additional electric power from Yunnan is intended to supply the rapidly growing industrial region of
the Pearl River delta in the province of Guangdong and the megacities of Guangzhou and Shenzhen.
In the future, the electricity generated by several hydro-electric power plants will be transported from
Yunnan via 1,400 km to Guangzhou over this long-distance HVDC link. This HVDC link will save
the CO2 emissions of more than 30 million tons a year. This corresponds to the amount of harmful gas
which would be produced otherwise, for example through the construction of additional conventional
fossil power plants in the province of Guangdong to serve the regional grid.
Fig. 28 gives an overview of this world’s biggest HVDC project.
Commercial Operation:
¾ 2009 – Pole 1
1,418 Km
5,000 MW
¾ 2010 – Pole 2
+/- 800 kV DC
Yunnan-Guangdong
Reduction in CO2
versus local Power Supply with Energy-Mix
32.9 m tons p.a. - by using Hydro Energy and HVDC for Transmission
Fig. 28: World’s first 800 kV HVDC – in China Southern Power Grid
6.2. Security of Supply for the Mega-Cities: Example HVDC Project Neptune – USA
After the 2003 blackout in the United States, new projects are gradually coming up in order to enhance
the system security.
One example is the Neptune HVDC project. Siemens PTD was awarded a contract by Neptune
Regional Transmission System LLC (RTS) in Fairfield, Connecticut, to construct an HVDC
transmission link between Sayreville, New Jersey and Long Island, New York. As new overhead lines
can not be built in this densely populated area, power should be brought directly to Long Island by
HVDC cable transmission, by-passing the AC sub-transmission network. For various reasons,
environmental protection in particular, it was decided not to build a new power plant on Long Island
22/30
near the city in order to cover the power demand of Long Island with its districts Queens and Brooklyn
which is particularly high in summer. The Neptune HVDC interconnection is an environmentally
compatible, cost-effective solution which will help meet these future needs. The low-loss power
transmission provides access to various energy resources, including renewables. The interconnection
is carried out via a combination of submarine and subterranean cable directly to the network of Nassau
County which borders on the city area of New York.
Neptune RTS was established to develop and commercially operate power supply projects in the
United States. By delivering a complete package of supply, installation, service and operation from
one single source, Siemens is providing seamless coverage of the customer’s needs. The availability of
this combined expertise fulfills the prerequisites for financing these kinds of complex supply projects
through the free investment market.
Siemens and Neptune RTS were developing the project over three years to prepare it for
implementation. In addition to providing technological expertise, studies, and engineering services,
Siemens also supported its customer in the project’s approval process.
Ed Stern, President of Neptune RTS: “High-Voltage Direct-Current
Transmission will play an increasingly important Role, especially as it
becomes necessary to tap Energy Reserves whose Sources are far away from
the Point of Consumption”
Safe and reliable
Power Supply for
the Mega Cities –
“Blackout
Prevention”
Customer:
Neptune RTS
End User:
Long Island Power
Authority (LIPA)
Location:
New Jersey: Sayreville
Long Island: Duffy Avenue
Project
Development:
Supplier:
NTP-Date:
07/2005
PAC:
07/2007
Consortium
Siemens / Prysmian
Transmission:
Sea Cable
Power Rating:
600/660 MW monopolar
Transmission Dist.:
82 km DC Sea Cable
23 km Land Cable
Fig. 29: Highlights of Neptune HVDC Project - USA
In Fig. 29, highlights of this innovative project that are typical for future integration of HVDC into a
complex synchronous AC system are depicted.
During trial operation, 2 weeks ahead of schedule, Neptune HVDC proved its Blackout prevention
capability in a very impressive way. On June 27, 2007, a Blackout occurred in New York City. Over
380,000 people were without electricity in Manhattan and Bronx for up to one hour, subway came to
standstill and traffic lights were out of operation. In this situation, Neptune HVDC successfully
supported the power supply of Long Island and due to this, 700,000 households could be saved there.
6.3. Green Power with Basslink HVDC – Australia
Fig. 30 gives an overview of the Basslink project in Australia, which transmits electric power from
wind- and hydro sources very cost-efficiently from George Town in Tasmania to Loy Yang in Victoria
and the same way back.
23/30
2005
Benefits
of HVDC
Clean & Low Cost Energy
over Long Distance – suitable
for Peak-Load Demand
Improvement of Power
Quality
Improvement of local
Infrastructures
Hydro Plants for:
¾ Base Load and
¾ Energy Storage
“flexible”
Plus Wind
Power
Benefits of HVDC:
¾ Clean Energy
¾ CO2 Reduction
¾ Cost Reduction
“fuzzy”
Covering Base and Peak-Load Demands
Fig. 30: Basslink HVDC – Sustainability of a “Smart” and flexible Grid
This happens by means of HVDC via a combination of submarine cable (with 295 km the longest
submarine cable in the world up to now), subterranean cables (8 km for reasons of landscape
protection) and overhead lines over a total transmission distance of 370 km. The nominal power is
500_MW at a DC Voltage of 400 kV and a current of 1250 A. The overload capacity of the
transmission system is 600 MW during 10 hours per day.
24/30
Both Victoria and Tasmania profit from the interconnection of their networks:
During times of peak load Tasmania delivers “green energy” from its hydro power stations to Victoria,
while Tasmania can cover its base load demands out of the grid of Victoria during dry seasons when
the hydro-reservoirs are not sufficiently filled. Furthermore, the island of Tasmania receives access to
the power market of the Australian continent.
Tasmania intends to install additional wind farms to increase its share in regenerative energy
production. The figure shows that hydro power is perfectly suitable to be supplemented with the rather
“fuzzy” wind energy – in terms of base load as well as through its ability to store energy for peak load
demands. So far, the DC link can do much more to reduce CO2 through the combined use of
regenerative energies.
6.4. HVDC Transmissions East-South Interconnector and Ballia-Bhiwadi - India
The HVDC East-South interconnection (commercial operation in 2003) uses both advantages, the
avoidance of transmission of additional power through the AC system and the interconnection of
power areas which can not be operated synchronously. Fig. 31 shows the geographical location of the
DC Interconnector and its main data. A view of the HVDC northern terminal in the state of Orissa is
given in Fig. 32.
Talcher
Kolar
2003
Fig. 31: Geographic Map and Main Data of Indian East-South Interconnector
In April 2006, Siemens was awarded an order by Powergrid Corporation of India to increase the
transmission capacity of the East-South DC transmission from 2000 MW to 2500 MW. As the upgrade
is now completed, it is possible to make maximum use of the system’s overload capacity. To increase
the capacity of the link, the Siemens experts have developed a solution known as Relative Aging
Indication and Load Factor Limitation (RAI & LFL). By these means, it is possible to utilize the
overload capacity of the system more effectively without having to install additional thyristors.
Furthermore, in March 2007, Siemens and consortium partner Bharat Heavy Electricals Ltd (BHEL)
have been awarded an order by the Power Grid Corporation of India Ltd, New Delhi, to construct a
new HVDC transmission. The purpose of the new HVDC transmission system is to strengthen the
25/30
power supply to the growing region around New Delhi. The system is scheduled to go into service in
November 2009. This is the fourth long-distance HVDC transmission link in India.
2500 MW
RAI & LFL: full Use of
Overload Capacity –
without additional
Thyristors
2007
2003
2000 MW
DC Station Talcher – State of Orissa
Fig. 32: Site View of Indian East-South Interconnector – DC Station Talcher
The power transmission system is to transport electrical energy with low loss from Ballia in the east of
Uttar Pradesh province to Bhiwadi, ca. 800 km away in the province of Rajasthan near New Delhi. In
comparison with a conventional 400 kV AC transmission line, this HVDC transmission link improves
transmission efficiency so that 688.000 tons of CO2 will be saved.
As head of the consortium, Siemens has overall responsibility for the project, including the design of
the HVDC transmission system, and will deliver the bulk of the core components. The company will
also undertake the transport functions, construction work, installation and start-up. Partner BHEL is
supplying transformers for one of the two converter stations as well as switchgear components. The
new long-distance HVDC transmission link is the second system that Siemens is building in India.
6.5. Getting more Power out of the Grid: SVC Siems - Germany
In Figs. 33-34, an innovative FACTS application with SVC in combination with HVDC for
transmission enhancement in Germany is shown [8, 14].
It’s a matter of fact that this project is the first high voltage FACTS controller in the German network.
The reason for the SVC installation at Siems substation nearby the landing point of the Baltic Cable
HVDC were unforeseen right of way restrictions in the neighboring area, where an initially planned
new tie-line to the strong 400 kV network for connection of the HVDC was denied. Therefore, with
the existing reduced network voltage of 110 kV, only a limited power transfer (450 MW) with the DC
link was possible since its commissioning in 1994, in order to avoid repetitive HVDC commutation
26/30
failures and voltage problems in the grid. In an initial step towards grid access improvement, an
additional transformer for connecting the 400 kV HVDC AC bus to the 110 kV bus was installed.
HVDC and FACTS in
parallel Operation
HVDC: Power Increase – from
450 MW to 600 MW Reduction
in CO2:
634,000 tons p.a.
Source:
Fig. 33: SVC Siems, Germany - Support of HVDC Baltic Cable
SVC - Essential for
enhanced Grid
Access of the HVDC
The Solution
The Problem – no Right of Way for 400 kV
AC Grid Access of Baltic Cable HVDC
2004
Fig. 34: The Solution – the first HV SVC in the German Grid at Siems Substation
27/30
Finally, in 2004, with the new SVC, equipped with a fast coordinated control, the HVDC could fully
increase its transmission capacity up to the design rating of 600 MW. In addition to this measure, a
new cable to the 220 kV grid was installed to increase the system strength with regard to performance
improvement of the HVDC controls.
The enhanced grid access of the HVDC can save an amount of 634,000 tons of CO2 emissions p.a.
through the import of more hydro power from Nordel to Germany.
Prior to commissioning, intensive studies were carried out; first with the computer program
NETOMAC and then with the RTDS real-time simulator by using the physical SVC controls and
simplified models of the HVDC [14].
In Fig. 34, a view of the Siems SVC in Germany is depicted.
7. CONCLUSIONS
Deregulation and privatization are posing new challenges on high voltage transmission systems.
System elements are going to be loaded up to their thermal limits, and wide-area power trading with
fast varying load patterns will lead to an increasing congestion.
Power System Expansion …
… with Advanced Transmission Solutions
HVDC PLUS
Fig. 35: From Congestion, Bottlenecks and Blackout
towards a “Smart Grid”
Environmental constraints, such as energy saving, loss minimization and CO2 reduction, will play an
increasingly important role [1, 10]. The loading of existing power systems will further increase,
leading to bottlenecks and reliability problems. As a consequence of “lessons learned” from the large
blackouts in 2003, advanced transmission technologies will be essential for the system developments,
leading to Smart Grids (see Fig. 35) with better controllability of the power flows.
28/30
HVDC and FACTS provide the necessary features to avoid technical problems in the power systems;
they increase the transmission capacity and system stability very efficiently, and they assist in
prevention of cascading disturbances. They effectively support the grid access of renewable energy
resources and reduce the transmission losses by optimization of the power flows.
Bulk power UHV AC and DC transmission will be applied in emerging countries such as India and
China to serve their booming energy demands in an efficient way.
8. REFERENCES
[1] European Technology Platform SmartGrids – Vision and Strategy for Europe’s Electricity
Networks of the Future; 2006, Luxembourg, Belgium
[2] DENA Study Part 1: „Energiewirtschaftliche Planung für die Netzintegration von Windenergie
in Deutschland an Land und Offshore bis zum Jahr 2020“;
February 24, 2005, Cologne, Germany
[3] Economic Assessment of HVDC Links; CIGRE Brochure Nr.186 (Final Report of WG 14-20)
[4] N.G. Hingorani: “Flexible AC Transmission”; IEEE Spectrum, pp. 40-45, April 1993
[5] FACTS Overview; IEEE and Cigré, Catalog Nr. 95 TP 108
[6] H. Breulmann, E. Grebe, M. Lösing, W. Winter, R. Witzmann, P. Dupuis, P. Houry, T. Pargotin,
J. Zerenyi, J. Dudzik, L. Martin, J. M. Rodriguez: “Analysis and Damping of Inter-Area
Oscillations in the UCTE/CENTREL Power System”;
Report 38-113, CIGRE Session 2000, Paris
[7] M. Luther, U. Radtke: “Betrieb und Planung von Netzen mit hoher Windenergieeinspeisung”;
ETG Kongress, October 23-24, 2001, Nuremberg, Germany
[8] H. Waldhauer: “Grid Reinforcement and SVC for full Power Operation of Baltic Cable HVDC
Link”; The 38th Meeting and Colloquium of Cigré Study Committee B4 “HVDC and Power
Electronics”, Technical Colloquium, September 25, 2003, Nuremberg, Germany
[9] G. Beck, D. Povh, D. Retzmann, E. Teltsch: “Global Blackouts – Lessons Learned”;
Power-Gen Europe, June 28-30, 2005, Milan, Italy
[10] U.W. Niehage: “Future Developments in Power Industry”; Key-Note Address at
AESIEAP, 28-05 September 2005, New Delhi, India
[11] U. Armonies, M. Häusler, D. Retzmann: “Technology Issues for Bulk Power EHV and UHV
Transmission”; HVDC 2006 Congress – Meeting the Power Challenges of the Future using
HVDC Technology Solutions, July 12-14, 2006, Durban, Republic of South Africa
[12] D. Povh, D. Retzmann, E. Teltsch, U. Kerin, R. Mihalic: “Advantages of Large AC/DC System
Interconnections”; Report B4-304, CIGRE Session 2006, Paris
[13] W. Breuer, D. Povh, D. Retzmann, E. Teltsch: “Trends for future HVDC Applications”;
16th CEPSI, November 6-10, 2006, Mumbai, India
[14] G. Beck, W. Breuer, D. Povh, D. Retzmann: “Use of FACTS for System Performance
Improvement”; 16th CEPSI, November 6-10, 2006, Mumbai, India
[15] R.P. Singh: “New Projects on HVDC in India”;
Brazil-China-India Summit Meeting on HVDC and Hybrid Systems – Planning and Engineering
Issues, July 16-18, 2006, Rio de Janeiro, Brazil
[16] R.P. Sasmal: “Planning Issues on HVDC Systems in India”;
Brazil-China-India Summit Meeting on HVDC and Hybrid Systems – Planning and Engineering
Issues, July 16-18, 2006, Rio de Janeiro, Brazil
29/30
[17] W. Ma: “Main Aspects of UHVDC System Planning and Design”;
Brazil-China-India Summit Meeting on HVDC and Hybrid Systems – Planning and Engineering
Issues, July 16-18, 2006, Rio de Janeiro, Brazil
[18] Y. Zeng: “Chinese CSG Experience on HVDC Transmission”;
Brazil-China-India Summit Meeting on HVDC and Hybrid Systems – Planning and Engineering
Issues, July 16-18, 2006, Rio de Janeiro, Brazil
[19] W. Breuer, M. Lemes, D. Retzmann, “Perspectives of HVDC and FACTS for System
Interconnection and Grid Enhancement”;
Brazil-China-India Summit Meeting on HVDC and Hybrid Systems – Planning and Engineering
Issues, July 16-18, 2006, Rio de Janeiro, Brazil
[20] V. Ramaswami, D. Retzmann, K. Ücker: “Prospects of Bulk Power EHV and UHV
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