Superconductivity and marine propulsion motors. Applications of high-temperature superconductors in energy
For at least another half century, ships will not noticeably change their appearance. But already now scientists and designers are dreaming of completely different, superconducting ships, in comparison with which the current ones, powered by coal and oil, with conventional propellers, will seem completely outdated.
The movement of a new type of ship - like the one shown above - will be based on the phenomenon of superconductivity, when some metals at extremely low temperatures cease to resist electric current. If an electric current is once passed through a superconducting substance, it can flow through the superconductor almost indefinitely. Therefore, devices using superconductivity must be extremely efficient. Currently, physicists are faced with the task of finding substances that will transform into a superconducting state at or near room temperature. However, even before such substances are created, liquid nitrogen may well find application as a coolant for superconducting devices.
The figure shown above shows a cross-section of one of the proposed superconducting propulsors. In it, superconducting magnets must eject water from the nozzles at enormous speed, thus creating thrust for the movement of the vessel. Devices of this type should consume very little electricity in operation.
Above is a picture of a fictitious ship gliding through the water at over 60 miles per hour. Instead of the usual fuel, such a high-speed vehicle will use economical superconducting electromagnets for movement. A new type of vessel, which is currently being developed, may appear and begin operating at the beginning of the 21st century.
Some developers believe that superconducting propulsion will eventually replace conventional devices for the propulsion of marine transport. In the new device, seawater flows into a central pipe. Inside it there is a number of channels. Inside each there are two electrodes, between which an electric current flows. A superconducting coil is installed outside the channel, creating a magnetic field. The interaction between the electric and magnetic fields inside the coil produces a force that pushes the water out of the channel.
On the image:
1 - intake pipe for sea water
2 - Propulsion mechanism
3 - Channel for the passage of sea water
4 - Electrode
5 - Coil made of superconducting material
6 - Magnetic flux
7 - Outlet pipe for sea water
For double propulsors, electromagnet assemblies I can be located under the ship's hull. In each such device, six electromagnets create a magnetic field. Each such electromagnet consists of a superconducting coil and two electrodes.
On the image:
1. - Vacuum cavity
2. - Vacuum chamber
3. - Liquid helium
4. - Electrode
5. - Thermal insulation pad
6. Water channel.
This finger rule shows the direction in which the force acting in such a coil occurs when the electric and magnetic fields interact. We point the left index finger along the magnetic field, the middle finger in the direction of the electric current, and then the open thumb will show the direction in which the force will act.
HTSC motors from MAI (L.K. Kovalev)
New types of electric motors based on bulk high-temperature superconductors
A series of hysteresis HTSC motors.
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Cryopump with HTSC engine |
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Main technical characteristics of hysteresis HTSC electric motors
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Areas of possible application of hysteresis HTSC engines: drive of cryopumps, drive of compressors, liquefiers and refrigerators, drive of high-speed centrifuges, textile industry, aerospace engineering, new cryogenic medical equipment.
Hysteresis HTSC motors. The principle of the HTSC engine is based on the use of the hysteresis phenomenon in bulk high-temperature superconductors. HTS motor rotor elements made of yttrium ceramic (YBa 2 Cu 3 O x) can be made in the form of plates, cylinders or rods. The rotating torque of the engine is determined by the area of the hysteresis loop of bulk HTSC materials and does not depend on the rotor speed. It has been shown theoretically and experimentally that when liquid nitrogen temperatures(77K) specific parameters of hysteresis HTSC machines are 3-4 times better than for non-superconducting hysteresis motors. The created hysteresis HTSC motors with a power of 100-4000 W operate reliably at 77K, which is so far unattainable for analogues based on HTSC composite wires.
Series of HTSC jet engines
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HTSC motor |
HTSC motor |
HTSC engine components |
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Main technical characteristics of reactive HTSC electric motors
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Areas of possible application of HTSC jet engines: drive of powerful cryopumps, high-speed ground transport, aerospace engineering, industrial drive in cryoenergetics.
Advantages of HTSC jet engines. It is known that the power and power factor of jet engines are determined by the degree of anisotropy of the magnetic properties of the machine rotor. In non-superconducting jet engines, this is achieved by using both magnetic and non-magnetic materials in the composite rotor. In HTSC jet engines, non-magnetic materials are replaced by HTSC materials. The rotors of HTSC jet engines consist of alternating HTSC (YBa 2 Cu 3 O x) plates and ferromagnetic plates, and have extremely high anisotropic properties (ferromagnetic properties in one direction and diamagnetic in the perpendicular). This makes it possible to obtain significantly better weight and dimensional parameters of the machines. Cryogenic HTSC jet engines operating in a liquid nitrogen environment have weight, size and energy parameters that are 2-3 times higher compared to traditional (non-superconducting) jet and asynchronous engines, and in the output power range of 5-20 kW they have a power factor cosj ~0 .7- 0.8.
Public acceptance. Work on the creation of new types of HTSC engines was awarded with Prizes of the RAS Council on HTSC problems in 1994 and 1995. and Diplomas of the International Conference on Superconductivity (Hawaii, USA in 1995 and 1997), Gold Medal and Diploma of the 49th International Exhibition of Innovations, Inventions and New Technologies in Brussels in 2000.
Cooperation and performers. For further development of work on HTSC engines, in particular, to increase power to 100-500 kW with the support and direct participation of corresponding member. RAS N.A. Chernoplekova has created an international cooperation, which includes the following organizations: MAI- lead developer, VNIINM named after Bochvar, VEI, ISTT RAS(Chernogolovka), Institute of High Technologies in Physics (IPHT, (Jena, Germany), electrical engineering company "Oswald"(Miltenberg, Germany), Electrotechnical Institute(Stuttgart, Germany), Dresden University(Germany), Oxford University(England).
Prof., Doctor of Technical Sciences Kovalev Lev Kuzmich
Address: Moscow, A-80, GSP-3, 125993. Moscow State Aviation Institute (Technical University), Volokolamskoe highway, building 4, department 310.
Foundation for Advanced Research / Photo: novomoskov.ru
The Foundation for Advanced Research and the SuperOx company held a seminar dedicated to the development of a new electric motor based on high-temperature superconductors with high power density.
The event was attended by experts and representatives of the Federal State Budgetary Institution “National Research Center “Kurchatov Institute”, JSC “Research Institute of Electrophysical Equipment named after. Efremov”, JSC “High-Tech Research Institute named after. Bochvar", Rosatom State Corporation, Russian Superconductor JSC, Moscow Aviation Institute, PJSC United Aircraft Corporation, United Shipbuilding Corporation JSC, the Russian Ministry of Defense, as well as the Military-Industrial Commission of the Russian Federation. As part of the seminar, a presentation of the technological line for the production of second-generation HTSC wires took place, demonstrating the latest Russian technologies for creating high-temperature superconductors.
The creation of a demonstrator engine is planned for 2018. Thanks to the new technology, the engine will be free of the traditional disadvantages of electric motor systems, and will become the starting point for the creation of a wide range of drive equipment operating on the principles of superconductivity. The creation of a compact electric motor of this type will be the next step in the development of superconductor technologies in Russia.
Technological line for the production of HTSC wires / Photo: fpi.gov.ru
The unique properties of superconductors - zero resistance and ultra-high current density - make them a key element for the implementation of breakthrough electrical solutions, opening up new opportunities for the electric power industry, transport systems, medicine, and space. Engines with high power density and efficiency are in demand in aviation and shipbuilding.
The basis of the technology is HTSC wires, which, like other superconducting materials, have no electrical resistance. The use of such a wire makes it possible to achieve a very high current density while using cables of a relatively small cross-section.
Currently, the Advanced Research Foundation is holding an open competition for the best innovative scientific and technical idea or an advanced design and technological solution for the development of advanced electrical systems and devices based on the principles of high-temperature superconductivity, the Advanced Research Foundation reports.
reference Information
Foundation for Advanced Study- a state fund whose purpose is to promote scientific research and development in the interests of Russian defense and state security, associated with a high degree of risk of achieving qualitatively new results in the military-technical, technological and socio-economic spheres, including in the interests of modernization of the Armed Forces Russian Federation, development and creation of innovative technologies and production of high-tech military, special and dual-use products.
Photo: fbcdn-sphotos-d-a.akamaihd.ne
History of creation
The history of the Foundation began on September 22, 2010, when at the Presidential Commission on Modernization and Technological Development of the Russian Economy, the Ministry of Defense was tasked with presenting proposals for the creation of a separate structure in the field of ordering and supporting breakthrough, high-risk research and development in the interests of defense and state security, modernization of the Armed Forces of the Russian Federation, as well as the creation of technologies and dual-use products, including taking into account foreign experience. In the same year, on the initiative of Deputy Minister of Defense Dmitry Chushkin, a division was created at Voentelecom OJSC for the collection and examination of proposals in the interests of the Armed Forces of the Russian Federation - the Research Center "Bureau of Defense Solutions".
The initiative to create a separate organization was again initiated by the Government at the end of 2011, when Dmitry Rogozin was appointed to the post of Deputy Prime Minister. The processing of the proposals collected by that time for the project of the National Security and Development Foundation, which he initiated, culminated in the preparation of the Federal Law “On the Foundation for Advanced Research,” which was submitted to the State Duma (a bill and accompanying documents, justifications and reviews of the Federal Law).
In fact, the Foundation began its activities in early 2013, when the budget, staff and management of the Foundation were approved. The Foundation's research directions were approved later - on August 7, 2013, when the first 8 supported projects were approved at a meeting of the Board of Trustees.
The structure of the Fund consists of three areas:
- Information Research
- Physical and technical research
- Chemical, biological and medical research
Directions
Photo: Sergey Shilovs / “Rare Earths”
The phenomenon of superconductivity opens up unique prospects in the field of electrical engineering, energy, and transport. Already today, what was previously considered science fiction is becoming possible: almost lossless energy transfer over vast distances, contactless high-speed ground transport, generation of ultra-high magnetic fields.
Superconductivity promises to bring revolutionary changes in a variety of areas, making interplanetary space travel possible using electric rocket engines, opening new paths to the creation of vertical take-off aircraft, helping to create devices for the effective diagnosis and treatment of complex diseases, and much more. The property of some electrically conductive materials to go into a state of superconductivity at ultra-low temperatures was discovered quite a long time ago, but the practical application of this effect became real only after the discovery of high-temperature superconductors (HTSC) in 1986, which was awarded the 1987 Nobel Prize in Physics. The second generation of wires based on HTSC allows them to be operated at a temperature of 77 K (the boiling point of liquid nitrogen). We talk about the development of the project on the practical use of HTSC materials and plans for the future with the founder of SuperOx CJSC Andrey Vavilov and general director Sergei Samoilenkov.
Vavilov Andrey Petrovich
Chairman of the Board of Directors of SuperOx CJSC, Doctor of Economics
Andrey Vavilov: When the project was launched in 2006, the main goal was to develop a technological approach and establish the production of second-generation high-temperature superconducting wire. Today the complete production chain, all equipment is localized here, in Moscow.
There are only five manufacturers of such wire in the world. We are the only manufacturers of HTSC wire in Europe and supply tape to such iconic consumers as CERN, MIT, Siemens, and the University of Cambridge.
In addition to the production of HTSC wire, we are constantly working on breakthrough HTSC devices, which not only contribute to the development of the industry, but also create a market for the consumption of HTSC wire. One of the already completed developments is superconducting current-limiting devices (CLDs). This device, which is extremely important for existing electrical networks, greatly increases the reliability of the energy system, reduces the cost of reconstruction of substations, and simplifies the operation of energy networks. The operating principle of these devices is based on the ability of a material to transition from a highly conductive state to a resistive state when exposed to a current above a threshold value. In 2017, SuperOx signed an agreement for the installation of the first 220 kV HTSC current-limiting device on the territory of the Mnevniki substation of United Energy Company JSC in Moscow. These works were supported by the Industrial Development Fund. Another direction is the creation of a superconducting electric motor for various applications. We received a grant from the Foundation for Advanced Research to create a 500 kW electric motor. As a result of this work, HTSC electric motors can be adapted for a wide variety of applications: aviation, shipbuilding, and rocketry. The key advantage of these engines is that, with the same size and weight, they produce significantly more power, many times more than traditional counterparts. Their efficiency is equally high at different powers. This provides enormous opportunities for optimizing the efficiency of operation in peak conditions (for example, during takeoff of an aircraft), reduces fuel consumption, and improves weight and size parameters. Airbus and NASA, which are also working in this direction, have calculated that a promising electric aircraft will use 4 times less fuel than it does now. And these electrical systems cannot do without superconductivity.
RZ: How is the company’s activity developing in this direction?
AB: The design of a future electric or hybrid aircraft will use HTSC cable, the first prototype of which is currently being created at SuperOx. The development of an electric aircraft involves the use of a distributed propulsion system; for this, electric engines without the use of superconductivity are not sufficiently efficient. Improvements in the weight and size parameters and power of HTSC electric motors have made it possible to begin the development of vertical take-off aircraft, for example, the tiltrotor type. Another increasingly common name is “air taxi”. Now the entire Silicon Valley is struggling to create such aircraft, and we are already working on a specific sample. Another project is the creation of an electric rocket engine (ERE) using HTSC materials. An electric rocket engine differs from chemical engines, which use burned fuel and an oxidizer, by its extremely low consumption of working fluid. Low-power electric thrusters have long been used in satellites to correct their position or orbit. Using our superconductors, we want to make such engines one or two orders of magnitude more powerful. If now these engines can only be used for orbit correction, with our HTSP electric propulsion it will be possible to create a space tug that can move cargo between orbits, for example, from a reference orbit to a geostationary one. This technology will allow flights between the Earth and the Moon, and further, all the way to deep space. Transporting cargo between orbits is a future that everyone dreams of, but no one has been able to get close to it yet. New materials have a great chance of making a dream a reality tomorrow.
RZ: At what stage is the development of an electric rocket engine now?
AB: We have completed the first design stage. In the coming months, it is planned to test individual components of the electric propulsion system with subsequent adaptation for use in space. We hope that in 3-4 years the first device with our electric rocket engine based on HTSC magnets will fly into space.
Samoilenkov Sergey Vladimirovich
General Director of SuperOx CJSC, Candidate of Chemical Sciences
RZ: In what other areas are high-temperature superconductors in general and your company’s products in particular used?
Sergey Samoilenkov: Although HTS were discovered 30 years ago, easy-to-use materials in the form of wires appeared on the market only ten years ago, at the same time as our company was founded. They can be used wherever high currents are transmitted or high magnetic fields are created, where there are restrictions on the weight or dimensions of equipment, where it is necessary to reduce losses, and so on. First of all, HTSC wires have found their application in the electric power industry. Superconductivity is the only way to create particle accelerators and colliders. All large accelerators that exist today are made of low-temperature superconductors. Second-generation HTSC materials will make it possible to increase the efficiency of existing equipment, increase the magnetic field and pave the way for new discoveries, the discovery of new particles and physical phenomena. Therefore, in particular, CERN is interested in our products.
RZ: Tell us how you collaborate with CERN?
SS: We are suppliers of superconductor and unique components based on HTSC, competing with four foreign companies. We win in competitive competition not due to low prices - our prices are often higher than those of our competitors, but due to the high quality and level of product customization. We supply CERN with special cables made from numerous, compactly folded flat strips. Now magnetic inserts are made from such a cable, which are planned to be installed inside the Large Collider in order to increase the magnetic field there. In the future, this will make it possible to make accelerators smaller in size. HTSC wires are the only materials capable of operating in ultra-high fields. Record high-temperature superconductor magnets are approaching the 40 Tesla limit. These are fantastic values for the magnetic field, which have become available to humanity not in a pulsed, but in a constant mode, only now, over the past two years.
HTS current limiting device
PLD equipment for obtaining a HTSC layer using pulsed laser deposition
RZ: How can your electric rocket engines be used in space technology?
SS: Important note: this does not mean the first stage for launching into orbit, not overcoming gravity, everything here is still standard. We are talking about engines with the help of which it will be possible to give objects a significant impulse for their movement in space. One of the most important problems now, which has not yet been solved and which our engine will help solve: how, using a small amount of fuel, that is, kilograms instead of tons, you can move in outer space at an acceptable speed. For example, the Hubble telescope now requires repair and maintenance. Humanity had the only way to reach it (and it is located in an orbit of about 570 km) - the space shuttle. After the closure of this program, no one, neither Roscosmos, nor China, nor NASA, nor SpaceX, nor Japan can fly there. This is impossible. We are creating an engine that could enable the creation of a tug spacecraft capable of handling such a task. The electric propulsion engine being created is capable of being switched on and off a large number of times, operate for more than 10 years and have sufficient power to move heavy satellites weighing 5–6 tons.
AB: If we consider the idea of deep space flights, this could become a reality thanks to this technology. All the films we watch, all the science-fiction ships that are out there, they all fly on this principle, and no one flies on a chemical engine.
RZ: Could you tell us about some special applications of superconducting materials?
SS: The most spectacular thing is magnetic levitation, created by the effect of superconductivity, when a superconductor can levitate and fly above a magnetic sheet. At SuperOx we even have a platform that can support up to two hundred kilograms of weight. A levitation train on a magnetic levitation, reaching speeds of up to 600 km/h, is already being tested in Japan. Launching airplanes and fighters - they can be accelerated using an electromagnetic catapult. All electrical and magnetic components of military equipment can be improved many times over. The weight of the power cable system on a ship can be reduced by 10 times! The Americans are now actively working on this, making special magnetic loops from HTSC that encircle the warship in all directions in order to make it invisible to magnetic detection systems and invulnerable to magnetic mines. The ship is often demagnetized on stationary stands, but when it moves over significant distances and, for example, crosses the equator, it again becomes easily observable and vulnerable. Therefore, it is important to create active demagnetization systems integrated into the ship, which are capable of adjusting as the ship moves.
One of six IBAD chambers - an installation for the production of buffer layers using texturing technology in an assisted ion beam
RZ: Why are ultra-high magnetic fields needed?
SS: Firstly, they are used in research and analytical instruments for studying substances and conducting fine chemical analysis, for example, using nuclear magnetic resonance. Secondly, accelerator technology, which we discussed above. There are also applied tasks, partly of defense significance, for example, hypersonic weapons, radio communications with re-entry spacecraft, with guided missiles moving in a plasma cloud. In all these cases, the higher the field, the better the quality of the created solution and technical characteristics, and often this relationship is nonlinear. For scale: permanent magnets can create a field of up to 1.5 Tesla, the most powerful magnets based on low-temperature superconductors, which are used in accelerators, colliders and tomographs, have a field of about 20 Tesla, and modern HTSC technologies can achieve a field of up to 40 Tesla, and this is not the limit.
RZ: What are your ambitions for the next few years?
AB: We want that, with the help of HTSC technologies, space tugs with an electric rocket engine will open a new page in the exploration of outer space, vertical take-off aircraft will become a new type of accessible and comfortable air transport throughout the world, and the architecture of the electric power complex will become simple, modern and reliable. We will strive to occupy, if not the main, then one of the central positions in this. The one who walks will master the road - we proceed from this. The SuperOx company has already come a long way from the development of a unique product to its integration into new breakthrough projects, and we plan to continue this.
TEXT: “Rare Earths” PHOTO: Sergey Shilovs
Reference
The SuperOx company was founded in 2006 by Andrei Vavilov. Today the company is the only manufacturer of second-generation high-temperature superconducting (HTSC) wire in Russia and Europe. Superconductors are unique materials that have zero electrical resistance and are capable of conducting currents at extremely high densities. Devices using oxide HTSC materials can change the face of the electric power industry and transport, opening the way to the creation of more efficient equipment for scientific research and special applications. The company's intellectual capital is based on more than 350 years of combined experience in the field of technologies for producing thin coatings from complex oxides and studying the properties of new superconducting materials. Today, the company's HTSC products are supplied to 15 countries around the world. In 2011, a subsidiary was opened in Japan - SuperOx Japan LLC. The effective collaboration of the two companies was the key to the rapid success of the project.
Read the full version of the material about the SuperOx company in the next issue of the Rare Earths magazine.
Until recently, practical use was very limited due to their low operating temperatures - less than 20K. Discovery in 1986 of high-temperature superconductors, which have critical temperatures
changed
situation,
simplifying the whole range of cooling issues (the operating temperature of the windings has “increased”, they have become less sensitive to thermal disturbances). Now there are opportunities
creation
generations
electrical equipment,
use
low temperature
superconductors
it turned out
would be extremely
expensive,
unprofitable.
The second half of the 90s of the last century is the beginning of a wide
offensive
high temperature
superconductivity for the electric power industry. High temperature
superconductors
use
manufacturing
transformers,
electrical
inductive
drives
unlimited
storage), current limiters, etc. Compared to installed
are characterized
reduced
losses
and dimensions and provide increased efficiency in the production, transmission and distribution of electricity. Thus, superconducting transformers will have
losses,
than transformers of the same power having conventional windings. In addition, superconducting transformers
able
limit
overload,
do not require mineral oil, which means they are environmentally friendly and not at risk of fire. Superconducting limiters
temporary
characteristics, that is, less inertial; The inclusion of superconducting generators and energy storage devices in the electrical network will improve its stability. Current carrying capacity
underground
superconducting
can be 2-5 times higher than ordinary ones. Superconducting cables are much more compact, which means their installation in dense urban/suburban infrastructure is significantly easier.
Indicative
technical and economic
South Korean calculations
energy workers,
carried out
long-term
planning
electrical
networks of the Seoul region. Their results indicate that laying at 154 kV, 1 GW superconducting
cables
it will cost
than usual.
turn on
design and installation of cables and conduits (taking into account the reduction in the number of required threads and, accordingly, the reduction in the total number of cables per km and the reduction in the internal diameter of conduits). European specialists, when studying similar issues, pay attention to the fact that with regard to superconducting
much
voltage.
Consequently, electromagnetic pollution of the environment will be reduced
densely populated
abandon ultra-high voltage lines, the laying of which
meets
serious
resistance from the public, especially from the Greens. The assessment made in the USA is also encouraging: implementation
superconducting
equipment
on generators, transformers and motors) and cables to the national energy sector will save up to 3% of all electricity. At the same time, widespread
latest
It was emphasized that the main efforts of developers need to be focused on: 1) increasing the efficiency of cryosystems; 2) increasing current-carrying capacity
superconducting
wires
dynamic losses and increase the share of superconductor over the wire cross-section); 3) reducing the cost of superconducting wires (in particular, due to increased productivity);
4) reducing costs for cryogenic equipment. Note that the highest “engineering” critical current density achieved to date (critical current divided by the total cross-sectional area) of a two-hundred-meter piece of Bi-2223-based tape is 14-16 kA/cm 2 at a temperature of 77 K. Planned commercialization is underway in developed countries
technologies
high temperature superconductors. The American program “Superconductivity for the Electric Power Industry 1996-2000” is indicative from this point of view. According to this program,
inclusion
superconducting
component
electrical equipment will provide global strategic
advantage
industry
XXI century At the same time, it should be borne in mind that, according to World Bank estimates, over the coming 20-year period (that is, by 2020), a 100-fold increase in sales of superconducting materials is expected.
equipment
electric power
devices
will increase
$32 billion (total
superconductors,
including
applications such as transportation, medicine, electronics and science will reach $122 billion).
Note that Russia, along with the USA and Japan, retained leadership
development
superconducting
technologies until the early 90s of the twentieth century. On the other hand, interests
industrial and technical
Russia's security undoubtedly requires their vigorous use both in the electric power industry and in other industries. The progress of superconducting technology and its “promotion” on the global electricity market is strongly
results
demonstrations
successful work of full-size prototypes for all types of products. What are
achievements
world
communities
in this direction? In Japan, under the patronage of the Ministry of Economy, Trade and Industry, long-term
program
development areas
HTSC equipment,
First of all, power cables.
The project is divided into two phases: phase 1 (2001-2004) and phase 2 (2005-2009).
Coordinators
are
Organization
Development of New Technologies in Energy and Industry (NEDO) and the Research Association for Superconducting Equipment and Materials (Super-GM). IN
involved
KEPCO, Furukawa, Sumitomo, Fujikura, Hitachi, etc. (HTS cables); KEPCO, Sumitomo, Toshiba, etc. (HTSC current limiters); TEPCO, KEPCO, Fuji Electric, etc. (HTSC magnets). In the field of cables, work will focus on the development
HTSC conductor
dynamic losses
cooling
capable
long term
support
temperature
cable (about 77K) 500 m long. According to the program, phase 1 ends with the production of a ten-meter cable at 66-77 kV (3 kA), having dynamic losses of no more than 1 W/m, and phase 2 ends with the production of a five-hundred-meter cable at 66-77 kV (5 kA) with the same losses. Works
the design has been worked out
manufactured
tested
the first sections, the cooling system was created and tested.
Parallel,
Furukawa, Sumitomo are pursuing another project to develop electric
Tokyo
superconducting. This project analyzed the feasibility of underground installation of a 66 kV (three phase) HTS cable having a diameter of 130 mm (which can be installed in existing 150 mm diameter conduits) in place of the conventional 275 kV single phase cable. It turned out that even in the case of construction of new
conduits,
the superconducting line will be 20% lower (based on the price of a superconducting wire of $40 per 1 kA m). The stages of the project are being carried out sequentially: by 1997, a thirty-meter
(single-phase)
prototype
with closed cooling cycle. It was tested under a load of 40 kV/1 kA for 100 hours. By the spring of 2000, 100 meters of 66 kV (1 kA)/114 MVA cable were manufactured - a full-size prototype with a diameter of 130 mm (design with a “cold” dielectric). The United States is demonstrating a large-scale approach to this problem. In 1989, at the initiative of EPRI, a detailed study of the use of high-temperature superconductors began, and already the following year Pirelli
Superconductor Corp. developed a technology for producing superconducting
"powder
tube").
Subsequently, American Superconductor constantly increased
production
power,
having achieved the figure of 100 km of tape per year, and in the near future, with the commissioning of a new plant in Divens (Minnesota), this figure will reach 10,000 km per year. The projected price of the tape will be $50 per 1 kA m (the company currently offers the tape at $200 per 1 kA m). Next
the most important
appearance
the so-called Superconductivity Partnership Initiative (SPI)
accelerated
development
implementation
energy-saving electrical systems. Vertically integrated
SPI commands
including
partners from
industry,
national
laboratories
and operational
companies,
carried out
two serious projects. One of them is a full-size prototype - a superconducting three-phase line (Pirelli Cavi e Sistemi,
tied
low voltage
124 kV/24 kV transformer (power 100 MVA) with 24 kV busbars of two distribution substations located at a distance of 120 m (Frisbee station of Detroit Edison, Detroit).
The line has been successfully tested
electricity reached consumers by “passing” through superconducting cables based on Bi-Sr-Ca-Cu-O. Three of these
(design
"warm"
dielectric, and each conductor was made of the same length
replaced
with the same
current-carrying
capabilities
the cable is designed for 2400 A (loss 1 W/m per phase) and is laid in existing hundred-millimeter underground channels. At the same time, the laying trajectory has turns of 90°: the cable allows bending with a radius of 0.94 m. We emphasize that this is the first experience in laying superconducting
current
distribution network, in the energy sector of a large city. Second
thirty meters
superconducting
at 12.4 kV/1.25 kA (60 Hz) which was put into operation on January 5, 2000 (operating temperature 70-80K, cooling
pressure).
A line representing three three-phase superconducting
provides
electricity three
industrial
installations
Southwire Company headquarters in Carolton, Georgia. Transmission losses are about 0.5% compared to 5-8%, and the transmitted power is 3-5 times higher than using traditional cables of the same diameter.
festive
atmosphere, the anniversary of the successful operation of the line with 100% load for 5000 hours was celebrated. Three more projects started in 2003, work on them is underway
primary
interesting
includes
installation of a 600 MW/138 kV underground superconducting line with a length of about 1 km, which will be included in the existing
load and will travel along existing conduits in East Garden City
Long Island.
Necessary
the cable will
manufactured
specialists from Nexans (Germany), based on a superconductor produced at the already mentioned plant in Divense, and cryogenic equipment
will deliver
In this case, the US Department of Energy finances this work in half, investing about $30 million; the rest is provided by partners. This line is planned to be commissioned by the end of 2005.
whom
manufactured
three-phase superconducting cable rated at 36 kV/2 kA (design
"warm"
dielectric,
cooling with liquid nitrogen under pressure; the critical reaches 2.7 kA per phase (T=79K)). At the same time, special attention
was given
development
conductor
km of tape based on Bi-2223), end devices, as well as its
connection.
was laid,
substation on the island of Amager (southern part of Copenhagen), which supplies electricity to 50 thousand consumers, including
lighting
network (output transformer power 100 MVA). The thirty-meter superconducting line began to operate on May 28, 2001: first, the superconducting cable was turned on in parallel with the usual one, and later it worked “alone”, and the nominal was 2 kA, losses were less than 1 W/m (the operating temperature was within 74- 84K). The cable transmits 50% of the total energy of the substation and replaces copper cables with a total core cross-section of 2000 mm 2. By May 2002, the cable had been in operation for 1 year while in a frozen state; During this time, he “supplied” 101 MWh of electricity to 25 thousand Danes - owners of private houses. No changes in cable characteristics were noted; all cryogenic systems operate stably. In addition to the Danish one, the pan-European project is interesting
to create an intersystem connection - a special three-phase superconducting line 200 m long, which is designed for 20 kV/28 kA.
To implement it, organized
consortium,
Nexans (Germany),
(France),
(Belgium),
specialists
Göttingen
Tampere (Tampere University of Technology). Among European manufacturers of superconducting cables, Pirelli Cavi e Sistemi stands out. Its production
power
allow
release
km of superconductor per year. Significant event - production
twenty meters
coaxial superconducting
(design
“cold” dielectric), designed for 225 kV. Pirelli, together with American specialists (Edison and CESI), is participating
creation
thirty-meter prototype cable at 132 kV/3 kA (1999-2003). Moving from cables to large electrical equipment - transformers, we note that of all the energy lost during transmission, they account for 50-65%. It is expected that with the introduction of superconducting transformers
will decrease
reach
Superconducting transformers will be able to successfully compete with conventional ones only if the relation (P s /k) is satisfied< P c , где Р с - потери в обычном трансформаторе, P s - потери
superconducting
transformer
operating temperatures), k is the refrigeration coefficient of the refrigerator. Modern technology, in particular cryogenics, makes it possible to satisfy this requirement. In Europe, the first prototype of a three-phase transformer (630 kVA; 18.7 kV/420 V) using high-temperature superconductors was manufactured as part of a joint
France), American
de Geneve) and put into operation in March 1997 - it was included in the Geneva electrical network, where it worked for more than a year,
providing
energy
Transformer windings
completed
wire
based on Bi-2223,
refrigerated
The transformer core is at room temperature. Losses were found to be quite high (3 W per 1 kA m) because the conductor design was not optimized for AC use.
The second project of the same participants - ABB, EdF and ASC - is a 10 MVA transformer (63 kV/21 kV), which in 2001 passed a full cycle of laboratory tests and was included in the French power system in 2002. ABB specialists once again emphasized that now the main
problem
development
economical
superconducting equipment, in particular transformers, is the presence of wires with low losses and high
critical
density
magnetic
field generated by the windings. The wire must also provide a current-limiting function. In Japan (Fuji Electric, KEPCO, etc.) they constructed a prototype of a 1 MVA (22 kV (45.5 A) / 6.9 kV (145 A)) superconducting transformer, which was included in the electricity company’s network in June 2000 Kyushu. IN
final
located
development
(Kyushu University
(Tokyo)) transformer
which is intended
installations
electromobile
composition. Preliminary calculations indicate that its mass should be 20% less than that of a conventional transformer of the same power.
A 1 MVA superconducting transformer has been successfully demonstrated in the USA, and work has begun on
apparatus
power
Waukesha Electric
and Electric, as well as ORNL). German specialists (Siemens) have created a transformer prototype
perspective
development of devices for 5-10 MVA) with windings based on Bi-2223, which can be installed on electric locomotives
designed
for ordinary
transformer.
The superconducting transformer is 35% smaller than conventional ones, and the efficiency reaches 99%. Calculations show that its use will provide savings of up to 4 kW per train and an annual reduction in CO 2 emissions by 2200 tons per train. The situation is more complicated with synchronous electric machines based on high-temperature superconductors.
It is known that ordinary power is proportional to its volume V; it is not difficult to show that the power of a superconducting machine is proportional to V 5/3, so the gain in reducing dimensions will only occur for high-power machines,
For example,
generators
ship
engines.
expect the introduction of superconducting technologies (Fig. 1).
testify
that a 100 MW generator requires a high-temperature superconductor having a critical current density of 4.5 10 4 A/cm 2 in a magnetic field of 5 Tesla. At the same time, its mechanical properties, as well as price, should be comparable to Nb 3 Sn. Unfortunately, not yet
exists
high temperature
superconductors that fully satisfy these conditions. WITH
low
American activity
European
Japanese
this area. Among them is a successful demonstration
together
with Rockwell Automation/Reliance Electric (partners in the already mentioned
synchronous
engine
at 746 kW and further development of the machine at 3730 kW.
specialists
design
engine
generator.
In Germany, Siemens offers a 380 kW synchronous motor using high-temperature superconductors.
Finland
tested
four-pole synchronous machine 1.5 kW with track windings made of wire based on Bi-2223; its operating temperature is 20K. In addition, there are a number of other applications of high-temperature superconductors in electrical engineering.
ceramics
High-temperature superconductors can be used to make passive magnetic bearings for small high-speed motors, such as pumps for liquefied gases.
The operation of one such engine, at 12,000 rpm, was recently demonstrated in Germany. As part of the joint Russian-German program, a series of hysteresis
engines
(power
"activities"
high-temperature superconductors - devices that limit short circuits to the nominal value. Ceramics are considered the most suitable materials for superconducting limiters.
and developments
devices
basic
electrical engineering
Great Britain,
Germany, France, Switzerland, USA, Japan and other countries. One of the first models (by ABB) was an inductive type limiter for 10.5 kV/1.2 MVA, having a Bi-2212 element placed in a cryostat. The same company has released a compact prototype - a 1.6 MVA resistive type limiter, which is significantly smaller than the first. During testing, 13.2 kA was limited in the first peak to 4.3 kA. Due to heating, 1.4 kA is limited at 20 ms and 1 kA at 50 ms.
Design
limiter
is
mm (weight 50 kg). Channels are cut into it, which allows you to have
equivalent
superconductor
m. Next
prototype
at 6.4 MVA. It is already possible to create a 10 MVA limiter, and the release of commercial limiters of this type can be expected in the near future. ABB's next target is a 100 MVA limiter. Siemens specialists tested inductive
limiters:
transformer
shielding the steel core with a superconducting winding and the second option - the superconductor is made in the form of a cylinder, with a copper winding wound on it. At the limiting
resistance
ohmic
inductive components. Due to possible overheating in areas with a short circuit, it must be switched off as quickly as possible using a conventional switch.
Return
superconducting
state
several
tens of seconds, after which the limiter is ready for operation. IN
further
resistive
limiter,
the superconductor is connected directly to the network and quickly loses superconductivity as soon as there is a short circuit
will exceed
critical
meaning.
heating the superconductor, the mechanical switch must break
several
half-cycles; cooling
superconducting
leads
to a superconducting state. The limiter return time is 1-2 s.
A single-phase model of such a limiter with a power of 100 kVA was tested at an operating voltage of 6 kV at a rated current of 100 A. Possible
short
short circuits,
kA, was limited to 300 A in less than 1 ms. Siemens also demonstrated a 1 MVA limiter at its stand in Berlin, with a 12 MVA prototype planned. In the USA, the first limiter - it had an inductive-electronic
developed
companies General Atomic, Intermagnetics General Corp. and others. Ten years ago, a current limiter was installed as a demonstration sample at Southern California Edison's Norwalk test facility. At a rated current of 100 A, the maximum possible short circuit of 3 kA is limited to 1.79 kA. In 1999, a 15 kV device with an operating current of 1.2 kA was designed, designed to limit a short circuit current of 20 kA to a value of 4 kA. In France, specialists from GEC Alsthom, Electricite de France and others tested a 40 kV limiter: it reduced the short circuit from 14 kA (the initial value before the short circuit was 315 A) to 1 kA in a few microseconds. The residual short circuit was switched off within 20 ms using a conventional switch. Limiter options are designed for 50 and 60 Hz. In the UK, VA TECH ELIN Reyrolle developed a hybrid (resistive-inductive) type limiter, which, during bench tests (11 kV, 400 A), reduced short circuits from 13 kA to 4.5 kA. At the same time, the response time of the limiter is less than 5 ms, already the first peak is limited; limiter operating time 100 ms. The limiter (three-phase) contains 144 rods made of Bi-2212, and its dimensions are 1 x 1.5 x 2 m.
In Japan, a superconducting current limiter was manufactured jointly by Toshiba and TEPCO - inductive type, 2.4 MVA; it contains a Bi-2212 solid ceramic element. All listed projects are prototypes of the “initial period”, which are intended to demonstrate
possibilities
superconducting
technology, its importance for the electric power industry, but still they are
so
representative,
so that you can
immediate
industrial implementation and successful marketing. The first reason for this caution is that Bi-Sr-Ca-Cu-O conductors are still under development and are currently being manufactured
critical
density
level of 30 kA/cm 2 with lengths of only about a kilometer. Further improvement of these conductors (increasing pinning, increasing core density, introducing barriers around them, etc.) should lead to an increase in J c to 100 kA/cm 2 or more.
essential
progress in superconducting technology and stimulates the development of new
designs
equipment
Certain hopes are also associated with successes in obtaining conductors with a superconducting coating (this is the next generation of superconducting wires), which have a noticeably higher J c in a magnetic field of up to several Tesla. Here it is possible to produce superconducting tapes capable of carrying currents of 1 kA at reasonable production costs. In the USA these tapes
are being developed
MicroCoating Technologies,
Superconductivity
Oxford Superconductor Technology.
The second reason lies in the fact that the issues of standardization of Bi-Sr-Ca-Cu-O conductors and the regulatory framework necessary for their use in the field of transmission and distribution of electricity are not sufficiently developed. Typically, standards provide guidance for conducting mechanical, thermal and electrical
tests
materials
equipment.
Since superconducting devices require cryogenic systems, they also need to be specified. Thus, before introducing superconductivity into the electric power industry, it is necessary to create a whole system of standards: they must guarantee high reliability of all superconducting products (Fig. 2).
is being undertaken
events
in this direction. Seven groups of specialists from four European countries are united in a joint project Q-SECRETS (it is subsidized by the EU) on quality monitoring
superconductors
effective,
compact
highly reliable
power transmission
One of the main goals of the project is to help create
expansion
"superconducting"
in the electricity transmission and distribution market. IN
conclusion
Mark,
despite
for large ones
potential
possibilities
application of high temperature
superconductors
power industry, significant research and development efforts will be required to make superconducting products viable in a modern market economy. At the same time, estimates for the near future give reason for optimism.
