Since the protection of power systems from the fault currents is very important, it is needed to develop a fault current limiter. Superconductivity is widely regarded as one of the great scientific discoveries of the 20th century. The method of critical current measurement in a magnetic field using a dc transport current has been developed for bulk superconductors. Superconducting fault current limiters first friday club 1st april 2011. The diamagnetic effect that causes a magnet to levitate above a superconductor is a complex effect. Bscco or bisko conductor and some are commercialized. Surge current protection using superconductor ppt slideshare. How to measure iv and critical current of a superconductor.
Ginzburglandau picture of critical current 637 energy minimization the gradient free energy under these assumptions can be written fgrad 2 2m jr j2 2 2m nsjr j2 j j. The emphasis is on experiment and recent developments on the high superconducting critical temperature tc cuprates. Fault current the short ckt current can exceed by a factor of 100 of the nominal current. Faultcurrentlimiters using high temperature superconductors offera solution to controlling faultcurrent levels on utility distribution and. Pdf insulation system for high temperature superconductor.
Fault current limiter fcl especially its resistive type, i. We use cookies to offer you a better experience, personalize content, tailor advertising, provide social media features, and better understand the use of our services. Sfcl can limit fault current fast, within 12 cycle, using quench effect of superconductor in case of current exceeds specified fault current. Major components of the generation, transmission power cables and devices for superconducting magnetic energy storage, distribution transformers and fault current limiters and enduse motor devices have been built, primarily using the bi,pb 2 sr 2 ca 2 cu 3 o x bi2223 a. Produce mechanical and thermal stress proportional to square of the current. In the original formulation its value is constant and it characterizes fully the properties of a material that is hard superconductor, i. Practical superconductor development for electrical.
A simplified phase diagram of a super conductor defines three regions. Wires are attached to a material at four points with a conductive adhesive. Download the seminar report for surge current protection. Sfcl is innovative electric equipment which has the capability to reduce fault current level within the first cycle of fault. Download seminar report for surge current protection using. Theoretically, the relaxation time of current carriers in the superconductor is greater than the age of. High temperature superconductor hts based sfcls are being been developed for many years. The transport current through the superconductor versus voltage across the taps iv is measured as a function of magnetic. Electrical manipulation of majorana fermions in an.
The only way to represent instability of the superconducting state is that ns, or equiv alently the order parameter magnitude, is driven to zero. Click here to see a superconductor suspended in air by fluxpinning. New superconductive material for longdistance energy. The problem with trying to pass huge amounts of current through a superconductor is that any flowing current creates a magnetic field circling around it amperes law. Though, work is proceeding at this time on hightemperature superconductor based devices, usable at 90 k and below. Simulation and performance analysis of resistive superconductor. Download as ppt, pdf, txt or read online from scribd. How to measure iv and critical current of a superconductor on.
Section 3 introduces various type of sfcl and their application. Insulation system for high temperature superconductor cables view the table of contents for this issue, or go to the journal homepage for more 2015 iop conf. The current distribution in a superconducting wire is obviously different from that of an ordinary metallic wire. The coil is now part of a superconducting loop, so its current will stay constant. The most common method of determining the tc of a superconductor. Then the iv measurements are repeated at the different values of strain required. The resistive type sfcl based on second generation 2g, ybco tapes are preferable because it limits the fault current within 1 or 2 ms.
Superconducting control for surge currents ieee journals. This is significant because inexpensive liquid nitrogen may be used for cooling. Intrinsic properties not surface specified number of junctions small volume less defects less heating. These are heavily influenced by the geometry of the conductor and can be reduced by decreasing the conductor dimension transverse to direction of local magnetic field. The current persists, it does not decay because the resistance of the ring is zero. Here we discussed the use of superconductor as protective device for surge current protection. An hts conductor type that is well suited for this application is a laminated sintered. Also, it can supply a solution on power system voltage sag problem. Superconductivity application in power system intechopen.
A fault current limiter is required to assure 1 rapid reaction to fault currents, 2 how impedance in normal. Several types of sfcls are developed and evaluated with different superconducting materials 16. Electrical manipulation of majorana fermions in an interdigitated superconductorferromagnet device shuping lee,1 jason alicea,2 and gil refael1,3 1department of physics, california institute of technology, pasadena, california 91125, usa 2department of physics and astronomy, university of california, irvine, california 92697, usa 3dahlem center for complex quantum systems, freie. Surge current protection seminar report slideshare. Download as doc, pdf, txt or read online from scribd.
A superconductor also expels all magnetic fields from inside itself meissner effect, so what you get is a lot of magnetic field lines all bunched up just outside the surface of the superconductor, which makes a strong magnetic. When you now switch off the normal coil, the fluxchange induces a current in the superconducting loop. A growing understanding of the conditions required for. Practical superconductor development for electrical power applications annual report for fy 1995 argonie national laboratory, argonne.
Then you cool the superconductor below its critical temperature. Explore surge current protection using superconductors with free download of seminar report and ppt in pdf and doc format. With the loop closed, the magnet is now in persist mode, so. The purpose of this paper is to provide a brief overview of the current status of the field of high temperature superconductivity. Conventional superconducting devices must be cooled to within a few degrees of 0 kelvin 273 o c. Dewhughes oxford university, department of engineering science, parks road, oxford ox1 3pj, uk submitted may 4, 2001. Lts are substances that lose all receptivity close to 4k, a temperature attainable only using by using liquid helium. Jan 19, 2012 second a superconductor is not loss free in ac operation, the magnetic as field generated by the current produces so called ac losses basically, just eddy current losses.
Systems designed to use superconductors to limit fault currents in. The advantage of using superconducting electromagnets is that the current only has to be applied once to the wires, which are then formed into a closed loop and allow the current and field to persist indefinitely as long as the superconductor stays below the critical temperature. To keep it superconducting, it is usually immersed in a coolant that is chilled by a refrigerator. Superconductivity brings sensitivity, accuracy and performance advantages beyond the theoretical limits of conventi onal electronics technology. This equilibrium position can be observed very sensitively using a light beam. The measurement of the critical current, i c, up to 50 a at a temperature of 77 k became possible by reducing thermal and mechanical stresses caused in the sample due to rapid cooling from the room temperature to 77 k and a electromagnetic force. An ordinary superconductor can generate an electric current when a magnet is placed nearby. Leggett, advisor the subject of this thesis is a study of the superconductornormal metal sn contact. Mar 26, 2014 seminar on surge current protection using superconductor submitted to. The sudden change in the superconductor resistance rsc is mainly due to the electrical properties of the superconductor material which can be macroscopically simplified into ej power laws, where the electric field depends on the current density and both parameters depend on temperature. Surge current protection using superconductor ppt 1. I tried to transfer monolayer wse2 from sapphire substrates to pdms, but i failed. Download surge current protection using superconductors seminar report, ppt, pdf, topics, abstracts, full documentation, full power point presentaion.
Oct 15, 2015 surge current protection using superconductor ppt 1. Illinois 60439 operated by the university of chicago for the united states department of energy under contract w31109eng38 tsaster gisi if ticin of tws. The current density of a superconductor is approximately to 0 times higher than that of copper if the current flow goes above this limit. Measurement of critical current for bulk superconductors. Emphasis is on balanced coverage, with a comprehensive reference list and significant graphics from all areas of the published literature. Additionally, in large scale superconducting systems, when all the necessary cryogenic components. Zero impedanceat normal operation high impedanceat faults. Surge current protection using superconductors seminars. Military benefits of superconductor based equipment.
Conductance of superconductornormal metal contact junction beyond quasiclassical approximation vladimir lukic department of physics university of illinois at urbanachampaign, 2005 anthony j. Critical current density of superconductors as a function. Models for fault current limiters based on superconductor. Supercurrent and critical currents cornell university. Surge current protection using superconductor ppt download. Surge current protection using superconductors seminar report. Any decay of the permanent current within the rings would be indicated by the light. The hts are substances that lose all resistance below temperature main tamable by liquid nitrogen. As a result an equilibrium position is established in which the angular moments of the permanent current and of the torsion thread balance each other. Resistive sfcl superconductor connected in series with the line to be protected. The act of moving a magnet toward a superconductor induces circulating persistent currents in domains in the material. Part of it is a consequence of zero resistance and of the fact that a superconductor cannot be shorted out.
Certain alloys, especially those of niobium, have critical magnetic elds in the tens of tesla, making superconducting magnets ideal for strong permanent magnets. Critical current density of superconductors as a function of. In case of a fault the inrush of current and magnetic field take the super conductor. The authors describe superconducting fault current limiters scfcl which. Abstract the recent growth of power circuit capacities has caused fault currents to increase. Superconductivity is observed in a large variety of materials but, remarkably, not in some of the best normal conductors like copper, silver and gold, except at very high pressures. Theoretically, the relaxation time of current carriers in the superconductor is greater than the age of universe. Current in a superconducting circuit physics forums. Critical current density of superconductors as a function of strain in high magnetic. Surge current protection using super conductors report scribd. Using superconductors would allow stronger magnets to be built, providing clearer pictures of various types of cells and tissues. The induced current is called the persistent current. The current that is not going through the current source anymore just goes through the formerly heated return path of the superconductor. Superconductors conduct electricity, offering zero resistance.
Insulation system for high temperature superconductor cables. Aug 04, 2008 super conductors are of two typeshigh temperature superconductors hits and low temperature superconductor lts. The most important practical characteristic of a superconductor is its critical current density. Surge current protection using superconductors seminar. Chiral superconductor generates electric current when. In probe ii, a solenoid is wound around a toroidal superconductor. The modelling was carried out using power system analysis toolbox while the simulation used matlab codes. Seminar on surge current protection using superconductors department of electrical engineering submitted to. That is, the external power supply can be switched off. Actually no decrease of current was observed over the period of three years.
Two newly published studies improve scientists understanding of the conditions required for superconductivity and how it can be achieved at realistic temperatures. Sep 23, 2016 the mgb 2 wire was tested with a very high current, up to 20,000 amperes, and this experiment confirmed the potential of mgb 2 as the superconductor of choice for longdistance energy transport. Second a superconductor is not loss free in ac operation, the magnetic as field generated by the current produces so called ac losses basically, just eddy current losses. Superconductivity is a unique and powerful phenomenon of nature. First, coat wse2 which is on sapphire with a thin film of pmma by spin coating. The shieldedcore limiter works only with ac currents and is much larger and. But there is one other physical limit the current density. Hampshire department of physics, university of durham, south road, durham dh1 3le, uk received 23 june 1998 a probe has been designed and built to measure the critical current density j cof. This phenomenon is now referred to as the meissner e ect. Through two of these points a voltage is applied and, if the material is conductive, a.
Dec 02, 2010 the current distribution in a superconducting wire is obviously different from that of an ordinary metallic wire. Largescale superconductor a pplication s, like f usion magnets, requi re high current capacity conductors t o limit system inductance and peak operating volta ge. An international team working together with the center for quantum materials, run. Higher currents than this will damage the superconductive disc. The mgb 2 wire was tested with a very high current, up to 20,000 amperes, and this experiment confirmed the potential of mgb 2 as the superconductor of choice for. Ampere per mm2 the current density of a superconductor is approximately to 0 times higher than that of copper if the current flow goes above this limit the superconductor starts to heat up and instantly loses its special. Surge current protection using superconductor ppt mahesh. Nearly a century after its first discovery, its full commercial potential is. Superconductivity, third edition is an encyclopedic treatment of all aspects of the subject, from classic materials to fullerenes. London 1 gave a phenomenological explanation of the meissner e ect. Another area is the production of squids which are magnetically sensitive sensors, sensitive enough to be able to detect electrical activity within the brain.