Superconducting power device

Abstract

One goal of one embodiment of the present invention is to provide a manufacturing method that produces high-temperature superconducting (HTS) and medium-temperature superconducting (MTS) materials for use in commercial applications. Thus, providing HTS / MTS devices is a related goal of some embodiments of the present invention. For example, the method of one embodiment results in a robust magnet configuration for use in first fully cryogenic (liquid cryogen) HTS linear, rotating, curved, etc. devices. The devices described herein are designed to function at liquid nitrogen (LN2) temperature using existing HTS materials and / or conventional materials that support the lower cryogenic temperatures of SCs.

Description

Technical Field

[0001] This application claims the benefit of U.S. Provisional Patent Application No. 63 / 366,927, filed Jun. 24, 2022, and U.S. Provisional Patent Application No. 63 / 374,321, filed Sep. 1, 2022, which are hereby incorporated by reference in their entirety.

[0002] This application is related to PCT Application No. PCT / US22 / 13662, filed Jan. 25, 2022, which is hereby incorporated by reference in its entirety.

[0003] This application is related to U.S. Patent No. 10,899,575, issued Jan. 26, 2021, which is hereby incorporated by reference in its entirety.

[0004] This application is related to U.S. Application No. 17 / 159,0347, filed Jan. 26, 2021, which is hereby incorporated by reference in its entirety.

[0005] (Field of the Invention) Embodiments of the present invention generally relate to power devices that at least partially comprise a superconducting linear medium. Such devices include fault current limiters, transformers, superconducting energy storage devices, etc., and devices that assist them such as superconducting rotary couplings, air core configurations, and associated winding techniques for electric machinery.

Background Art

[0006] Superconductors (sometimes referred to herein as "SCs", which also refer to "superconductivity") could enable the manufacture of innovative devices that will be 100% efficient in the future and can adapt to increasing energy and power requirements in a compact package. Commercially available advanced SC products such as magnets, cables, and cable magnets do not practically exist because superconductors, including those that can withstand higher temperatures, are fragile. More specifically, those skilled in the art will understand that the fragile nature of existing SC media makes it extremely difficult / expensive to incorporate into realizable devices.

[0007] High-temperature superconducting (HTS) devices, i.e., those that operate at liquid nitrogen (LN2) temperature, are desired across many industries. Conventional copper (Cu) permanent magnet devices inherently generally have power output limits associated with the air-gap magnetic flux density (B) and heat output. The air-gap is the non-magnetic space between the primary and secondary sides of any electromagnetic device. For example, addressing the need for cooling in copper-based devices often increases the system weight because conventional devices use iron to increase the air-gap (B), sacrificing weight gain. Conversely, HTS devices have no thermal losses and have a six-fold increase in power compared to conventional devices due to the B output.

[0008] Despite the benefits provided by HTS devices, no HTS or medium temperature superconducting (MTS) electrical devices, such as transformers and fault current limiters, have emerged beyond laboratory-based proof-of-concept models. Due to the aforementioned winding limitations, some attempts at manufacturing HTS winding devices have focused on creating pancake stacks or HTS strip-based electrical devices with limited protection from HTS windings and operating stresses. Pancake stacks increase the harmonic content, move the coil away from the air gap, and reduce air gap B. Thus, pancake stacks are not very suitable for complex windings such as armature coils of electromechanical (motor / generator) devices and are not curved to protect the HTS medium, such as tape, from quenching (i.e., an abnormal or unexpected transition from the superconducting state to the resistive state) due to local increases in magnetic flux. Due to the difficulty of winding complex HTS coils, creating fully cryogenic HTS devices (devices with cryogen-based primary and secondary sides) has been rarely attempted. Other MTS solutions have lower material costs but are associated with greater fragility when reacting, higher cryostat costs, and complexities associated with lower operating temperatures when using potentially dangerous cryogens.

[0009] Those skilled in the art will likely understand that the current energy delivery system, often referred to as the "power grid," is very outdated. Additionally, transitioning to a modern power grid will create new technical challenges regarding power systems not designed for today's or future energy requirements. Any new future grid or grid upgrade must enable safe, remotely auditable power generation, an increase in the number of distributed energy resources, energy diversification, and smart power distribution. The problems include the need for fault current limiters (FCLs) that are intended to limit the power of disruptive power failures to acceptable levels, transformers that are intended to change the power ratio of voltage and current, and SC magnetic energy storage devices that are intended to store power.

[0010] Those skilled in the art will understand that manufacturing for HTS applications requires that complex geometries experience low winding stresses, which enables increased operating values. This requirement is exacerbated when manufacturing complex geometric magnets, which are classified by their major mounting and rotational requirements, including solenoids (often mounted on a common central swivel platform), planar (such as racetrack coils or curved planar cosine-theta magnets, often mounted on cylindrical tools), and spherical (such as baseballs or yin-yang magnets). Understanding of HTS operating values, their performance, advancements in cryogenic system reliability, connections, etc., and the reduction of HTS material costs during production are collectively targeting SC manufacturing as the remaining issues regarding commercial SC applications.

Summary of the Invention

Means for Solving the Problems

[0011] One goal of an embodiment of the present invention is to provide a manufacturing method that yields high-temperature superconducting (HTS) and medium-temperature superconducting (MTS) materials for use in commercial applications. Thus, providing HTS / MTS devices is a related goal of some embodiments of the present invention. For example, the method of one embodiment yields a robust magnet configuration for use in first fully cryogenic (liquid cryogen) HTS linear, rotational, curved, etc. devices. The devices described herein are designed to function at liquid nitrogen (LN2) temperature using existing HTS materials and / or conventional materials that support lower cryogenic temperatures of SCs.

[0012] (Compact High-Performance Superconducting Devices) Providing high-performance compact superconductor (SC) devices is one aspect of some embodiments of the present invention. The SCs can be fabricated or processed using techniques described herein or in the patents / applications listed above. The envisioned compact devices include, but are not limited to, fault current limiters (FCLs), SC energy storage (SMES) devices, SC transformers, and any device that includes or uses high electromagnetic (EM) fields and / or currents that are partially or fully generated by high-performance SCs. High-performance SCs enable SC operation at higher temperatures and generally include materials that are more (even significantly more) mechanically fragile. While some of the present disclosure focuses on compact systems, those skilled in the art will understand that SC devices of any size can be manufactured.

[0013] (Fully Cryogenic HTS Devices) Providing fully cryogenic electrical devices is one aspect of some embodiments of the present invention. As used herein, "fully cryogenic" refers to both the primary side (e.g., the stator for an electromechanical machine) and the secondary side (e.g., the rotor for an electromechanical machine) being at LN2 temperature. The envisioned fully cryogenic devices can be electrical machines (e.g., motors / generators), fault current limiters (FCLs), superconducting magnetic energy storage (SEMS) devices, transformers (Xfmrs), etc.

[0014] As mentioned above on the [Air Core Device], many electrical devices employ an iron core that generates a high B. Hybrid cores are also used, but they are not a good solution due to the high B that far exceeds the iron (Fe) lamination saturation level of about 0.6 - 1.1 T for the expensive laminations and associated losses. Further, Fe is heavy and brittle at cryogenic temperatures. Thus, another aspect of some embodiments of the present invention is to provide a device that employs an air core instead of an iron core to handle high magnetic flux (B). Thus, such a device is lighter than conventional iron core devices, eliminates iron hysteresis losses, reduces circulating current losses, increases the allowable primary and secondary coil winding areas, provides a flexible structure for large and complex well installations, uses the complete B path or magnetic energy, and has a lower total harmonic distortion emitted from the associated electrical circuit. An air core design without any need for Fe B continuity means that all magnets can be wound at once or in connectable segments when forming the final device.

[0015] (Magnet Saddle Winding Angle and Flux Exclusion) Providing a magnet with a saddle winding formed from a curved and / or tapered winding pattern to adapt to the B path requirements for reducing end losses is yet another aspect of some embodiments of the present invention. More specifically, since the highest HTS induced current occurs when the external B is perpendicular to the tape width (the tape is an example of a linear medium), each HTS tape is installed to set its width parallel to the highest B. In particular, due to SC flux exclusion that can assist B induction, a properly designed complex 3D shaped SC magnet enables high efficiency and a compact and lighter sizing for B without exceeding the SC critical value. In one envisioned HTS solenoid embodiment, the tapered HTS ends have an angle that provides a winding tapered end stack top, which results in a high packing ratio HTS configuration that helps move the internal solenoid end B concentration safely beyond the saddle winding.

[0016] (Toroidal Magnet Device) Some embodiments of the devices described herein, such as FCL, Xfmr, and SMES devices, possess a toroid that is separated into radial and / or axial magnet components. For example, the winding robot automated production (WRAP-M) device for magnets described herein or in the patents / applications referenced above enables winding into toroidal sections where SC and copper can be connected. One benefit of this configuration is the extreme B efficiency experienced by the toroid. One embodiment employs a toroidal magnet component that is separated into different primary toroidal windings along the winding axis of the magnet and secondary toroidal windings radially along the winding axis, and the SC is used to flux separate each axial magnet. During a controlled quench of the secondary toroidal winding, the inductance of the primary toroidal winding rapidly increases when each primary side is flux connected.

[0017] (Toroidal Outer Winding for Toroidal Flux Exclusion) In some cases, the toroid must have a good coating, such as a B exclusion coating of the toroidal area where the conductor spreads at the outer toroid diameter. When applicable, conductors in toroidal, poloidal, or another configuration can be connected to assist with the coating. One embodiment provides a layer of toroidal conductor with a connected layer of poloidal conductor used to flux exclude a layer of the SC toroid.

[0018] (B Isolation / Exclusion and Path Control) One important part of the design of the present invention and the process for its design is the ability to control the B path through B exclusion during different operating modes. For example, some embodiments possess a toroidal magnet with carefully designed geometries for each phase, such as controlling the B path, employing EM shielding such as SC B exclusion use, and / or increasing operating and system efficiency. These aspects also include compactness, weight, and the ability to install multiple phases within a single cryostat, which has extreme advantages such as those listed and minimizes thermal and electrical connections. Embodiments include both the SC FCL and SC FCL Xfmr described herein.

[0019] (3D Device Component Printing) Embodiments of the present invention assist in improved manufacturability and component count, compactness and weight, power density, winding groups, cryogenic - conductive cooling, and cost.

[0020] (Compact Device Cooling) One embodiment of the present invention directly incorporates a cryocooler and / or a cryogenic head into a central solenoid and / or toroidal cavity, providing thermal efficiency and faster cooling times. The envisioned cryocooler also reduces failures due to hot spots, eliminates most, if not all, concerns about external coolant connections, and provides a compact system. One envisioned centrally - located coolant reservoir is configured to refrigerate all layers of the device and may enable the ability to refill the reservoir from the outside. The outer walls can be super - insulated and vacuum - jacketed. For compactness and efficiency, the electrical leads inside the COTS are vapor - cooled cryogenic bayonet connectors with Peltier leads, etc.

[0021] (Coolant Pressure Pull - Down) During cooling, as the coolant turns to gas, back pressure is generated within the device's coolant reservoir, which will delay the cooling and recovery times. Thus, some embodiments of the present invention employ means for pressure pull - down, which helps remove the cryostat pre - cooling gas purge.

[0022] (Coolant Gas Vent Pipe) During a failure, the extreme liquid - to - gas expansion ratio (1:694 for LN2 to GN2) presents concerns about pressure relief accidents and GN2 asphyxiation. Thus, some devices employ a dedicated thick - walled vent pipe with regularly - spaced redundant pressure relief valves (PRVs) and high - pressure burst disks, which remove GN2 from the enclosed footprint while maintaining GN2 in the system for rapid failure recovery.

[0023] (Rotary Refrigerant and Vacuum Equipment) Some embodiments of the present invention directly mount refrigerant and vacuum equipment such as cryoheads, cryocoolers, and vacuum pumps on moving parts. One embodiment is an electromechanical rotor that provides cooling and vacuum space options. One embodiment potentially employs a central axis mount that rotates on one or both sides of the central axis of the device. One such embodiment employs a slower rotating device such as a direct drive wind turbine. Another embodiment mounts the equipment on an outer radius rotor with an inner radius stator. To adapt to the rotating configuration, special connections often have to be used. Such connections can include warm - cryogenic gases and fluids, power connections, sensor connections, evacuation, etc. Finally, specialized couplings for the use of refrigerant, vacuum, power, and sensor lines, or some other connection, etc., for rotation or for rotary connection via means of a rotating motion, are required.

[0024] In one embodiment, a rotor - based SC permanent switch is used to short - circuit the field coils of an electromechanical device in the wound induction mode and the synchronous mode when setting the field current. One embodiment of the present invention employs a rotary coupling that uses cryogenically cooled HTS in a phase configuration such as a + / - DC bus in the middle of the coupler. The HTS resides in the refrigerant inflow / outflow line to maintain the SC state regarding the HTS. Outside the refrigerant line, slip ring sensors and control lines or a field coil permanent switch for on / off control are installed outside the cryogenic temperature and the center of the power rotor. All coils share the same DC power.

[0025] As mentioned above on [thin magnet], the SC tape is one type of linear medium used in an envisioned electrical device. An electrical device of one embodiment employs a thin magnet with a primary coil (i.e., rotor) and a secondary coil (i.e., stator) that are at least partially composed of rectangular HTS. One embodiment uses a pair of rectangular HTS (often a 0.1 mm wide HTS tape that totals 1 mm thick HTS) against a much wider cross-sectional geometry (e.g., 2 - 12 mm) by aligning the tape length with the magnetic length of the solenoid axis. This orientation creates a shared mutual inductance area that removes the problem of the embedded HTS B exclusion layer. This orientation also provides a high fill factor that results in very high inductance and efficiency, high current per turn (and thus high B per turn), and small air gaps that facilitate power handling. Further, the thin layer provides a good cooling path relative to a typical wire solenoid that holds many turns where the outer layer thermally insulates the inner layer. These aspects of some embodiments enable a closely packed radially separated coil that functions like a single connected magnet when the secondary magnet quenches and it then magnetically couples to the primary magnet (such as in mode 2 as discussed later in this description for SC FCL and SC FCL Xfmr) etc., when B exclusion is removed. Loosely wound single to double groups of turns aligned per layer in an open coil allow B penetration across the winding layer. Closely wound turns for single to double layer solenoids with SC B exclusion, particularly relevant to wide SC tape, are optimal for single coil B and secondary side - overall coil EM shielding. These benefits are improved by employing many nested solenoids.In summary, "thin magnets" have: 1) increased power density and efficiency (power density is 1 / 6 to 1 / 10 of conventional ones, and efficiency increases from the range of 70 - 93% to beyond the range of 95%, potentially up to >99%) due to the property of being extremely close to HTS with high current in each, where they are more separated, greatly reducing current, and in many cases, B is directed away from the air gap and relies on Fe to direct those Bs into the air gap; 2) ideal EM shielding; 3) the possibility of providing high inductance full-length coils; 4) increased HTS critical B (i.e., the critical magnetic flux required for higher energy / power SC-based devices) that reduces the possibility of unwanted quenches; and 5) enables improved cooling paths.

[0026] The envisioned SC devices include FCLs, SMESs, transformers, and hybrid devices that employ thin magnets. In many applications, since B is very high, "thin magnet" devices are from hybrid to fully air-core based, increasing efficiency by removing the hysteresis and conductive losses of iron cores. In many embodiments, the concept of "thin magnets" enables very thin magnets, where one or more sets of primary and secondary solenoids are nested inside each other to improve magnetic coupling and SC flux exclusion.

[0027] (Thin magnet winding) The SC coil is a continuously connected coil that can be wound on top of each other without any splices within and across a single to multiple magnet windings (splices are standard practice for most HTS magnets joined together). In one embodiment, the continuous windings of all HTS concentric layers on the primary and secondary sides are wound simultaneously, starting from the smallest radius outwards. The secondary HTS end shield comes with options such as a spiral or linear of the smallest winding. The HTS configuration can short-circuit one or both ends of the secondary solenoidal magnet stack, which can then complete the closure of the secondary electrical loop by short-circuiting the solenoid outer magnet using this secondary end shield. This secondary end shield often uses smaller HTS tapes with lower critical currents, which will facilitate a more controlled quench in the secondary end shield. As mentioned above, in one embodiment, the primary and secondary wound magnets are installed inside each other in a nested manner, and each respective primary and secondary side consists of continuous windings. An additional flat secondary end shield that can be wound in a pancake or bifilar manner can be installed at one or both ends of the primary and secondary nested magnets to further include B. In one embodiment, the secondary coil is longer than the primary side, and the secondary end shield is installed in close proximity to the solenoid magnet, which will 1) improve primary side isolation, 2) increase EM shielding, 3) remove harmonics, and 4) reduce unwanted HTS tape width induction B. The secondary end shield further provides a simpler and improved cooling path with a large surface area for cooling the controlled secondary quench and AC transient currents and quench energy.

[0028] In some embodiments, multiple coiled layers are wound separately, with or without intervening splices, and combined into concentric solenoids. For example, each coil is wound on a cylinder, such as a fiberglass laminated G-10, which facilitates winding, provides structural support and electrical insulation for the coil, and the cryogen functions as a dielectric. The grooves inside the G-10 allow LN2 penetration. The G-10 is also used to maintain the coil size during thermal contraction and to allow for some Lorentz force expansion of the coil. Any additional dielectric can be an LN2-permeable cryogenic dielectric.

[0029] Embodiments of this thin magnet design include SC Xfmr and FCL devices. For example, thin magnet SC FCL solenoidal and SC FCL Xfmr toroidal embodiments are further discussed below.

[0030] (WRAP-M Magnet Winder) The aforementioned WRAP-M is capable of simplifying complex compact windings and thus, potentially, winding multiple layers without any splices (e.g., HTS splices: two primary sides in the FCL input leads and HTS shunts, two secondary sides in the solenoid to the end connections) between concentric solenoids due to the possibility of fewer turns and a compact size. For continuous winding, the WRAP-M winds all HTS concentric layers of the primary side, and separately the secondary side, at once, starting from the minimum radius and working outwards. The primary and secondary sides are then inserted inside each other, with solenoid end shields at the preferred cooling ends. The secondary winding is wound to partially overlap to 1) increase EM shielding, 2) remove harmonics, and 3) reduce unwanted HTS tape-width induced B.

[0031] (Cable magnet winding) In particular, for higher current transformer (Xfmr) and FCL embodiments, the assumed fully transposed SC cable is used for both the HTS cable shunt and the HTS winding, increasing current handling and power ratings, reducing AC losses by enabling uniform current distribution, assisting in uniform quenching and thermal heating / cooling, and providing mechanical support. The fully transposed SC cable is ideal for cable magnets. Embodiments for special cases are two-stage (L-R) FCLs without any HTS shunt resistive FCL. Here, a primary reactive power compensation capacitor (Z VC ) with series resistance is added to remove the LC oscillating current, reduce the primary side impedance during normal operation, and enable a second current path (I2).

[0032] (Trapping field magnet) One embodiment of the present invention is a device that uses a passive secondary side composed of an SC trapping field magnet (TFM) (possibly connected to an HTS tape) that assists in flux exclusion.

[0033] (HTS used in the device) Insulated HTS is expected to control quench propagation for all quench energies that potentially go to a single location. PPLP, G-10, or Ultem LN2-permeable cryogenic dielectrics and semiconductor tape layers in exposed HTS insulation for >5 kV are used. Any HTS with low dropout is not used. The HTS has a significant amount of copper to accept current during fault conditions. All conventional conductors are also maintained at LN2 temperature to increase performance and reduce losses. Wider HTS for FCLs of the same power and size provide higher current output with a faster response time from normal to fault mode.

[0034] (Secondary End Shield) As introduced above, some of the assumed devices complete the closed loop by shorting the solenoidal secondary side and using a smaller HTS tape with a lower critical current, and employ components with a secondary HTS shield such as a minimum turn helix, linear, etc. at one solenoid end. The secondary end shield provides a simpler cooling path with a large surface area for 1) EM shielding efficiency, 2) controlled secondary quench, and 3) heating such as AC transient current and quench energy. The SC secondary end shield can be used to further isolate the primary coil. The SC secondary end shield of one embodiment is connected to all other SC secondary coils and can be used to quench before other secondary magnets, which leads to better quench and cooling control.

[0035] (Primary End Shield) In one embodiment, the primary side incorporates an end shield, e.g., a bifilar pancake, within the voltage limit. As will be understood by those skilled in the art, the bifilar coil is a special type of pancake coil with a double helix shorted at the center. This configuration provides a side-by-side current path that cancels self and induced B, thus reducing the coil inductance.

[0036] (Superconducting Fault Current Limiter) As referred to in some instances of this specification, embodiments of the present invention are full cryogenic HTS devices, combined inductive and resistive type FCLs, and multi-stage FCLs, with the goal of producing FCLs that enable grid modernization through improved stability. More specifically, it is another aspect of some embodiments of the present invention to provide an energy delivery system that is safe, resilient, reliable, and can handle the burdens associated with fundamental changes in both supply-side and demand-side technologies. Grid modernization adds new forms of distributed generation, storage, and load capacity, higher density, bidirectional power flow, and many more interconnections to support increasing demand, which increases the amount of power that can be supplied at any one branch. Thus, the envisioned system includes branch circuits with upgraded fault handling devices that can handle higher fault current limits, additional power transformer capacity, additional energy storage capacity, etc. Fault current limiters (FCLs), transformers, SMES, etc. for incorporation into power devices on grids, microgrids, and mobile platforms are described below.

[0037] The FCL of one embodiment is capable of passive operation mode. More specifically, for effective and safe operation, it is important that the power grid be isolated from and recover from an electrical fault. The FCL of one embodiment enables direct connection of electrical components without the risk of cascading faults, distributes electrical loads, and provides near-instantaneous isolation of the fault state with a rapid return to full or partial operation upon removal of the fault. The FCL response is often set to a fault current below the desired system trip current of circuit breakers and switchgear. In the event of a fault operation, a redundant system maintains the operation of the remaining electrical system, and surplus cryogenic cooling can be provided to assist in fault recovery. When the fault is removed, any severely fault-damaged components are isolated and / or the remaining healthy components are restored to their operating status using the fault-recovered system components. At a minimum, the envisioned SC fault current limiter functions as a high-power surge protection device and a power regulator, reducing the fault by 20 - 50% with little or no quenching or operational impairment. Unlike conventional fault breakers and fuses, the envisioned SC fault current limiter enables rapid fault recovery, often within a few milliseconds in the absence of quenching, due to proper thermal load interruption rather than a destructive fault system.

[0038] The FCL of one embodiment of the present invention generally comprises an SC primary coil surrounded by an SC secondary coil, and the SC primary and secondary coils are surrounded by a Cu primary coil. The coil assembly is installed in a housing that also houses end shields. The primary coil may surround a solid or hollow (i.e., air) core. The core may comprise a reservoir for containing a cryogen.

[0039] The housing also houses an HTS shunt that connects the primary power input of the overall device, which can be a cable of a length with a single fully-transposed (FT) group of four (4) tapes per group, to the output. The FCL winding is designed to 1) maximize HTS stabilizer (non-SC conductors within the HTS for protecting the SC) fault protection (within size limits) to protect the HTS during a fault, and 2) set the minimum number of parallel coils per operation to handle power and enhance the fault current response. In one embodiment, the % rated fault current (I) is a setting regarding its FCL mode for quenching and recovery, including a Cu coil bathed in LN2. To save on HTS costs, more parallel paths are provided that reduce inductance, with a trade-off of increased quenching energy removal. As mentioned above, since the widest HTS is used for the desired power and size of the FCL, a higher current output is provided that reduces the response time from normal to fault mode. The HTS secondary side incorporating the widest possible HTS allows for fewer turns and lower L, and thus provides an improved EM shielding layer. The FCL design described herein is configured to provide a quenching resistance (R), a constant inductance (L), and a copper (Cu) R energy dissipation mode, including FCL quenching energy removal / loss.

[0040] Loosely wound single to double layer windings aligned per layer in the open coil allow for B penetration across the layer. Due to the closely wound windings with B exclusion, a single to double layer solenoid without any windings covered by separate SC layers, especially regarding wide SC tapes, is optimal for a single coil and is improved by the design of multiple nested solenoids.

[0041] The FCL of one embodiment also has a set number of turns and area of the coil, thereby providing an optimal inductance for FCL response. To assist with the high-speed cooling of the outer HTS secondary and primary sides, an outer secondary coil having half of the inner coil turns is provided. The inner coil turns also facilitate parallel connection impedance matching. Those skilled in the art will understand that embedding the coil in a layer that gives an undesired thermal or B response is avoided. The FCL also has additional coil turns added for current balance and to achieve a common quench. The FCL may also enable the primary HTS coil to be set for high current operation with a reduced non-fault to high-fault impedance. External power is connected to the innermost primary coil positioned around a cryocooler (i.e., the core of the FCL) with a refrigerant reservoir that provides enhanced cooling. The innermost coil is configured to receive the fault current and thus quenches first. FCL quench energy loss / removal is linear with the square of the current but with an inductance, while the time lag of the inductance is exponential with respect to the inductance. This response helps to define the desired fault-limiting energy type and level.

[0042] (Reverse current connection) Adjacent primary and secondary coils may include reverse current connections between the primary and secondary sides and between secondary sides to further reduce the common operating mutual inductance, response time, induced current, and associated AC losses. Non-reverse current connection embodiments from primary to primary are used to maintain a high mutual inductance for requirements such as inductive FCL faults. Reverse current connection embodiments from primary to primary include switching of the primary connection for current direction and reduced inductance operation.

[0043] (Radially and / or axially single magnets connected in parallel) The HTS windings of a single magnet on the primary and / or secondary sides connected in parallel radially and / or axially are embodiments for any high current requirements.

[0044] The device envisaged enables a new EM configuration at full cryogenic temperature and is a commercially feasible device where both the primary and secondary sides of the device are cooled with a cryogenic agent such as LN2, and is the first inductive and resistive HTS FCL, a stepped FCL, a HTS FCL, including multiple turns of complex curves per layer, multiple concentric rings, SC primary and secondary coils (e.g., HTS primary and secondary coils). This superconducting FCL is passive or active AC and / or DC, is compact and simple, is of low weight (air core and less Cu), and with the envisaged multi-stage high-power FCL design, can be more reliable and have less FCL and grid burden. The FCL stepped fault energy removal enables 1) by measuring the fault power surge, to gradually increase the fault power reduction response that self-protects not only the FCL but also the lid components, 2) to have faster fault and recovery times, and 3) to safely handle extreme continuous faults even exceeding the FCL rating where the SC has no theoretical voltage limit. When a high-power long-term fault occurs exceeding the FCL rating, the FCL can automatically respond and cannot destructively open the circuit (even without a cryogenic agent) to protect the grid. Thus, the FCL described herein is 100% reliable.

[0045] By adopting the winding techniques described herein, thermal hot spots that can lead to quenches are reduced. The benefits of the FCL of one embodiment are: 1) the only combined inductive and resistive type FCL known to involve multiple levels / stages of fault protection (higher capacity, faster response and recovery times with fewer FCLs and less grid burden), as further discussed below; 2) the highest specific power and power density; 3) the lowest voltage for the same power, removing voltage reduction while providing a higher safety rating; 4) no internal heat generation during normal operation, which leads to: 5) the most compact (multiple coaxial solenoids and cryogenic cooling center); 6) the lightest weight (air core, fewer turns, and most compact); 7) the highest fault impedance per unit volume; 8) higher reliability and less grid burden due to multi-stage and limited splices; 9) a cycle response time of less than half; 10) negligible resistance losses and low impedance during normal operation (no air core and coil B crosstalk), thus minimized stray losses, no hysteresis losses, and more current per HTS tape, thus the highest efficiency; 11) self-triggering; 12) self-recovery under load; 13) safely wound HTS commercial production magnets; 14) multiple turns of complex curves and multi-layer HTS coils for each first layer; 15) multiple HTS concentric rings; 16) fully cryogenic devices; 17) the least amount of tape / wire required for all HTS FCLs; 18) the lowest total life cycle cost; 19) the longest life, where cryogenic cooling slows down or stops all chemical reactions such as surface oxidation and dielectric aging for heating devices, enabling a doubling of the unit life for conventional FCLs; 20) no external electromagnetic (EM) field during normal operation; 21) increased safety through reduced voltage; 22) enabling new grid requirements and applications; 23) compliance with new regulations; 24) including easy manufacturing of modular storable / replaceable sub-assemblies from winding for all frame sizes. The performance increase is related to HTS conversion and proper use.Due to the extreme specific power, this FCL provides the maximum device and system benefits for more power, which competing technologies often require when they are too large or too heavy.

[0046] In the FCL embodiment, an air-core FCL reactor requires a low normal operating impedance (Z) and a high controllable fault impedance. The lower normal operating impedance also removes external EM. The inductive FCL desires a high inductance over resistance and provides an extremely fast and efficient fault operation. Ideally, the primary-side impedance (Z P )(see figure) increases according to the equation [Z P = Z S ×(N P / N S ) 2 . Thus, the best high-impedance fault response is a larger number of primary turns (N P ) and a smaller number of secondary turns (N S ). Thus, N P is set higher for the inductive fault response which is the second stage. N S is set low, one layer is possible, and the main purpose is to electromagnetically (EM) shield the primary coils from each other during normal operation.

[0047] (Multi-stage FCL) All HTS FCLs enable the highest power density inductive fault capability and the lowest non-fault energy loss operation for any FCL, but multi-stage FCLs are further used to combine the advantages of inductive and resistive type FCLs and eliminate their disadvantages while splitting the fault energy. Each HTS fault mode removes a large amount of fault energy separately (an operation to quench energy, which for the L fault mode is proportional to the area under the FCL B curve), but is at an energy much lower than all the fault energy of any single fault. This is due to the need for cryogenic cooling and the fact that thermal energy is (current) 2Protect the FCL from hot spots, etc. that are proportional to. The measured FCL response reduces grid loading and improves reliability. The multi-stage design is practical only for a full HTS FCL due to HTS power handling, fast quenching, resistance increase, and B elimination. When the fault is removed, the multi-stage design provides a faster recovery time since each stage recovers separately in the reverse order of the fault operation.

[0048] The FCL of one embodiment of the present invention enables a three-stage ((R / L-L-L / R mode) power handling methodology with all the passive operating modes described herein.

[0049] (- Mode 0 (normal operation, no fault)) During normal mode, all HTS have no resistance. Most of the current flows through the HTS shunt (I1) for AC (alternating current) or through the HTS cables and coils (I1 and I2) for DC (direct current). For AC, the secondary side B elimination shields the primary side and the Cu primary coil from each other. This significantly reduces the inductance, and thus the primary side impedance is limited to the winding leakage impedance. For DC, all current follows the lowest resistance path with various levels of HTS quenching and increasing Cu resistance without any inductance effect.

[0050] - Mode 1 (R / L - Resistive / Inductive Fault Mode). Mode 1 is defined by a fault in the SC primary coil, the current is directed to the SC primary coil, and the induced current in the SC secondary coil provides a B - exclusion effect. Mode 1 shorts out the entire FCL using an HTS cable shunt that clearly exceeds the operating current but quenches in less than half of the full FCL fault response design. The SC primary - side impedance is set to limit the FCL Mode 1 fault energy. All currents move into the SC primary coil (I2) operating with a power - limiting SC primary - coil reactance where most are inductive while operating at a higher power level. Low - to - medium - level fault energy is removed via the HTS shunt quench and delayed via the isolated SC primary coil. Thus, Mode 1 power adjusts the line by removing all partial - power design faults in less than a quarter - cycle due to the nature of the resistive - circuit increase and recovers within milliseconds to seconds depending on the load. To provide a high - power but compact inductive FCL, multiple primary and secondary concentric HTS layers are wound together, operate in parallel, and are connected in series and / or parallel depending on the power handling.

[0051] (- Mode 2 (L - Inductive Fault Mode)) The FCL shifts to Mode 2 when the secondary quenches at a set full - fault power level, which increases the secondary resistance, decreases the induced current, and leads to the collapse of the secondary EM shield (Z S ). The SC primary and shunt coils are magnetically connected, increasing the high mutual inductance (Z P +Z PCu) results in. The secondary windings generate a rapid high resistance from their quenches, further increasing the fault impedance. High-level fault energy is removed through the quenches of the secondary coils and delayed through the B-connected SC primary coils. This mode is set to remove all standard design faults within 1 / 4 cycle due to the nature of the inductive circuit increase and then recover within 0.1 seconds to several seconds depending on the secondary load. Due to this HTS flux exclusion, the radially inner secondary side of each SC primary side prevents the main B of the SC primary concentric solenoid from connecting to itself, and the secondary sides on both sides of each SC primary side prevent the SC primary coils from connecting to each other. Only the stray B of the SC primary side remains as it is. All secondary windings are short-circuited for current balance and to achieve a common quench. To increase the fault flux coupling, the leakage flux is minimized by shortening the distance between the windings, and the parallel Cu primary side is wound outside the outermost secondary side for additional inductive fault impedance.

[0052] (-Mode 3 (L(self) / R fault mode)) In FCL mode 3, the SC primary coil quenches at the set full-fault power level, and all remaining fault energy proceeds to the Cu primary coil that receives negligible power during normal operation. At this point, the entire FCL is inefficient but powerful in limiting the fault, and the HTS must be protected. The full-fault current (I3) moves to the parallel conventional Cu primary resistor and inductor (Z PCu )). The Cu primary side is cryogenically cooled to assist in power interruption. The parallel inductance is (Z p) is removed, resulting in a purely self-inductance. The Cu primary side is initially at LN2 temperature, and Cu in LN2 has a conductance approximately eight times higher. As the fault persists, the LN2 evaporates over time, thus significantly increasing the Cu resistance, which provides an optimal increasing variable resistance response. High-level fault energy is removed through the quenching of the SC primary coil and the increasing Cu primary resistance and delayed through the B-connected Cu primary and the SC primary coil. Mode 3 is set to remove the remaining fault current within a few milliseconds and then recover within a few seconds depending on the load or, otherwise, within a few minutes for extreme fault cases exceeding the FCL specification. Due to the high Mode 3 current, after the LN2 level is reduced, in Mode 3, the Cu coil rapidly heats up, and there is a risk that the FCL will open-circuit fail. The SC FCL of this embodiment can safely handle extreme continuous faults due to the stepwise fault energy removal technique that reduces the full fault energy during and within each fault mode.

[0053] The transition to Modes 2 and 3 must consider sufficient Cu primary side impedance to handle the high input current regarding the set voltage to remove the thermal runaway situation. Each mode, especially Mode 3, must not have less impedance than the previous mode; otherwise, recovery will not occur. All fault mode values are set through the FCL design and can be easily changed using WRAP in one embodiment. The induction current technique and the reverse winding of the Xfmr magnet for FCL operation can be adopted. The SC secondary coil has a reverse current connection option from the SC primary side, reducing the SC primary side B limit within the induction B and reducing the common operating mutual inductance, response time, induction current, and associated AC losses.

[0054] The FCL multi - stage design of one embodiment is practical only for a full HTS FCL due to HTS power handling, fast quench, resistance rise, and B - elimination. The full HTS FCL enables the highest power - density fault - current - limiting ability of any FCL, but a three - stage (R / L - L - L / R mode) FCL is further used to combine the advantages of inductive (operation: a faster current transient is decelerated with a decreasing amplitude that introduces perturbations and reduces system stability and power transfer) and resistive (operation: dissipates energy, the voltage in normal operation drops with a sudden hard - on operation and has a longer recovery) FCLs while removing their disadvantages. Each fault mode removes a large amount of fault energy separately (i.e., it is an operation into quench energy, which, for the L - fault mode, is proportional to the area under the curve) (see, for example, FIGS. 7b and 11b), but is much lower in energy than all the fault energy of any single fault. The lower - fault - energy approach of the staged design helps to reduce the terminal over - voltage per fault and protects the FCL by quenching the entire SC volume of each mode at once, which removes hot spots where the thermal energy is proportional to the (current) 2 to remove.

[0055] The foregoing relates to a three - stage system, but a two - stage (L - R) FCL embodiment is also devised that does not have any HTS shunt - resistive FCL. A SC primary - reactive - power - compensation capacitor (Z VC ) with a series resistance to remove the LC (inductive and capacitive) oscillating current reduces the SC primary - side impedance during normal operation and enables a second current path (I2).

[0056] (Superconducting Transformer with SC FCL) The concept of the FCL described herein, including HTS and MTS embodiments, can be applied to an electrical transformer, i.e., a Xfmr (sometimes referred to herein as an FCL Xfmr or simply an Xfmr) that employs an SC FCL as described above. In one embodiment, the transformer is a high-frequency transformer. One embodiment of such an Xfmr may include a 3D printed core to support more advanced requirements such as high-frequency switching operations. During normal operation of a two-stage transformer, adjacent SC primary and secondary sides are B-connected, but the SC primary side from the SC primary side and the secondary side from the secondary side are B-isolated. Embodiments include both toroidal and solenoidal magnet configurations (see figures). In a toroidal configuration, one embodiment of the transformer excludes the outer Cu winding until a two-stage quench event begins to occur. In a solenoidal configuration, one embodiment of the Cu windings is to place them on the outside of the HTS magnet, thus minimizing their normal operation induced losses. Like the FCL, the Xfmr described herein operates in the modes that will be described below.

[0057] The Xfmr winding of one embodiment maximizes HTS stabilizer fault protection (within size limits) to protect the HTS during a fault, sets the high current side with respect to the minimum number of parallel coils per operating current (power handling) to save HTS cost (L-drop per parallel path), then enhances the fault current response [% rated fault current (I) is the setting regarding its FCL mode for quenching and recovery including a Cu coil immersed in LN2], sets the high voltage side to the number of parallel coils impedance-aligned for the desired voltage, then enhances the fault current response, uses the widest HTS for the desired power and size, provides a higher current output with a faster response time from normal to fault mode, the low voltage, high current side is a wider HTS tape and is thus expected to be the secondary side wound over the SC primary side (the widest HTS secondary side gives fewer turns with an improved EM shielding layer), sets the number of turns and area of the coil to provide L for Xfmr and FCL response (the coils are set for current balance and to achieve a common quench), does not embed coils in the layer giving an unwanted thermal or B response, and is designed to minimize pre-quench B leakage into the Cu winding. The outer diameter of the secondary side of the toroid must have good B exclusion covering the toroidal area where the conductor spreads. A secondary side tape of a Cu sheet and / or poloidal magnet configuration coupled toroidally can be employed for this covering.

[0058] Similar to the SC FCL described above, the Xfmr of one embodiment of the present invention utilizing an SC FCL enables a three-stage (L-R / L-R / L mode) power handling methodology with all the passive operating modes described herein.

[0059] - Mode 1 (L - inductive fault mode). In Mode 1, the HTS inductance is at 100% rated Xfmr operation (I 1P and I 1SRemove low - energy faults exceeding (). This mode adjusts the power of the line by immediately operating to remove all partial power design faults.

[0060] (- Mode 2 (R / L - Resistive and Inductive Fault Mode)) Usually, the Xfmr side that first exceeds the HTS critical current, which is the high Xfmr current side, quenches at 50% rated maximum fault current. This connects the Cu Xfmr on that side (e.g., I 2S ) electrically to the unquenched HTS Xfmr side (e.g., I 1P ). This mode is set to remove all standard design faults within 1 / 4 cycle due to the nature of the resistive circuit increase and then recover within 0.1 seconds to several seconds depending on the secondary load.

[0061] (- Mode 3 (R / L - Resistive and Inductive Fault Mode) The next Xfmr side that exceeds the HTS critical current (usually the low Xfmr current side) quenches at 75% rated maximum fault current. This connects both Cu Xfmr sides (I 2P and I 2S ). At this point, the entire FCL is inefficient but powerful in limiting the fault, and the HTS must be protected. The Cu is cryogenically cooled to assist in power interruption. The Cu primary side is initially at LN2 temperature, and Cu in LN2 has approximately 8 times the conductance. As the fault persists, the LN2 evaporates over time, thus significantly increasing the Cu resistance, which provides an optimal increasing variable resistance response. This mode is set to remove the fault within a few milliseconds and then recover within several seconds or, for extreme fault cases exceeding normal FCL specifications, within a few minutes depending on the load. Due to the high Mode 3 current causing a reduction in the LN2 level, in Mode 3, the Cu coil will heat up rapidly and there is a risk that the FCL will open - circuit fail.

[0062] For SC FCLs and FCL Xfmrs as well, the transition to modes 2 and 3 must take into account sufficient Cu primary-side impedance to handle the high input current with respect to the set voltage for removing the thermal runaway situation. Each mode, especially mode 3, must not have less impedance than the previous mode; otherwise, recovery will not occur. All fault mode values are set via the FCL design and can be easily changed using WRAP in one embodiment for the manufacturing method. Inductive current techniques and reverse winding of the Xfmr magnet for FCL operation can be employed. The SC secondary coil has reverse current connection options from the SC primary side, reducing the SC primary-side B limit within the induced B and reducing the common operating mutual inductance, response time, induced current, and associated AC losses.

[0063] Xfmrs with FCL multi-stage designs are practical only for full HTS FCLs due to HTS power handling, fast quenching, resistance increase, and B exclusion. Full HTS FCLs enable the highest power density fault current capabilities of any FCL. A three-stage (L-R / L-R / L mode) FCL further uses to combine the advantages of inductive (operation: faster current transients are decelerated with decreasing amplitude while introducing perturbations that reduce system stability and power transfer) and resistive (operation: dissipates energy, the voltage of normal operation drops with a sudden intense turn-on operation and has a longer recovery) FCLs and remove their disadvantages while splitting the fault energy. Each fault mode removes a large amount of fault energy separately (operation to quench energy), but at an energy much lower than all the fault energy of any single fault. This lower fault energy of the multi-stage helps to reduce the terminal overvoltage per fault, protects the FCL by quenching the entire SC volume of each mode at once, which removes hot spots where the thermal energy is proportional to the (current). 2 to remove.

[0064] (Superconducting Fault Current Limiting Toroidal Transformer) The toroid is separated into axial and radial magnet components for single-phase to polyphase multi-tap optional transformers (Xfmrs) with overlapping or separable magnets. Combining windings and phases in a single toroid provides a more reliable unit from fewer components while reducing weight, size, capital, and maintenance costs and increasing efficiency (the toroid is the most efficient known B-magnet path).

[0065] In this embodiment, the toroid is separated along the winding axis into axial toroidal winding sections of equal phase, and in each axial cross-section is radially separated into SC primary and secondary magnets of each phase. The sections are wound in less than half of the toroid, such as one-third for a three-phase device. Winding in one-third enables the three phases to be constructed on a single toroid without the need for any splices within the magnet. The total B across all phases cancels due to phasing sequencing. Each phase separation will include a high-voltage dielectric that allows B to pass and cooperate with a cryogen that functions as a dielectric. Superconducting (SC) layers are used to radially B-separate each magnet. The SC and copper (Cu) toroidal sections are wound on top of each other and then connected. In this toroidal configuration, the Xfmr eliminates the outer Cu winding up to a quench, resulting in a very efficient Xfmr and fast-acting FCL operation.

[0066] In one embodiment, a high-temperature SC (HTS) "thin magnet" design will be wound in a toroidal pattern. The Xfmr is evenly wound and electrically phased on a single toroid with a Cu Xfmr on top of the SC Xfmr. Each phased secondary side is placed directly on top of its respective phased SC primary side to assist in the induced secondary Xfmr action. HTS B exclusion minimizes leakage B, which keeps B in the toroid for Xfmr action, shields each phase from induced currents from other phases, and enables FCL options. HTS secondary side (I 1S ), Cu primary and secondary sides (I 1P and I 2S) All of the induced current in is wound such that both the HTS secondary Xfmr current and any leakage flux are added to the Xfmr action. For any B that can escape from the inner toroid, the outer LN2-cooled Cu Xfmr toroidal phase winding captures that B with a slight resistance, increasing the overall efficiency by removing any possible leakage B.

[0067] The secondary side is expected to be HTS with a wider width than the SC primary side to achieve improved secondary side B exclusion. The low voltage, high current side is a wider HTS tape and is thus expected to be the secondary side wound over the SC primary side. To remove leakage B into the Cu windings, the outer diameter of the secondary side of the toroid must have good B exclusion covering the toroidal area where the conductor spreads. A toroidally coupled poloidal secondary side tape can be employed to assist with this covering. A fully transposed cable is an option as a higher current Xfmr side option depending on the current rating and losses from standard to fault operation as well as cooling and structural requirements. Reverse winding of the Xfmr magnet for induced current techniques and FCL operation will be studied but is not expected to be adopted.

[0068] Structurally, the toroid is held at the phase change location. This location also provides a cryogenic path to the toroidal center that can be conduction or bath cooled. Bath cryogenic cooling at the toroidal center is only possible when concerns about the spread of LN2 failure have been removed. A cryocooler installed at the toroidal center provides a high-speed cooling option while minimizing any B that the cryocooler can be exposed to during fault operation from the Xfmr.

[0069] The toroidal transformer experiences very efficient normal operation when the B path is completely enclosed within the torus and the mutual inductance is clearly sized for Xfmr action. When either SC side quenches, an instantaneous resistive FCL action occurs. When the outer SC quenches, an instantaneous inductive FCL action occurs, leading to a two-stage quench event. In one embodiment, the toroidal core is 3D printed.

[0070] (Secondary Inductive Heating Modification) The superconducting (SC) secondary stabilizer can experience significant heating after an SC quench. One embodiment employs non-insulated HTS with a shorted Cu material such as a sheet wound intermediate to the secondary HTS to address this issue. The HTS significantly reduces any B heating when the secondary side quenches. The Cu sheet not only provides a large Cu area for current but, more importantly, effectively transforms the entire secondary side into a single turn that removes the large induced emf and all associated heating.

[0071] (Superconducting Magnetic Energy Storage) The windings for the use descriptions herein are applicable to superconducting magnetic energy storage (SMES) including embodiments of HTS and MTS SMES. One embodiment is a compact HTS-based "thin magnet" SMES. Another embodiment is a toroidal SMES that better approximates the ideal limit of the magnet B as the device increases in size by reducing the stray B.

[0072] (Superconducting Flywheel Energy Storage) The windings for the use descriptions herein such as "thin magnet" are applicable to superconducting flywheel energy storage devices including embodiments of normal HTS and MTS for high-speed and high-power flywheels.

[0073] (Superconducting High-Field Magnets) The windings for the use descriptions herein such as "thin magnet" are applicable to superconducting high-field magnets including embodiments of HTS and MTS high-field magnets for high-energy physics (HEP) and fusion applications above 3 tesla (T).

[0074] (Superconducting Space EM Shielding) The windings for the use descriptions in this specification such as "thin magnet" are applicable to superconducting electromagnetic (EM) shielding magnets including embodiments of HTS and MTS EM shielding magnets.

[0075] (Cryogen for Other Supplementary Energy Storage and Power Generation) Storage is performed via cryogen gas expansion that is used to generate electricity for immediate use or for further electrical storage. The cryogen energy power generation system can be used independently or as part of a larger system via common cryogen gas and / or liquid connections etc. In one embodiment, a cryogen station provides for the use of cryogen for distributed energy storage when using a high cryogenic liquid to gas expansion ratio for smart grid detection and protection capabilities at each cryogen station and for LN2 expansion etc. The system operates in particular for open and closed systems for LN2, and when the cryogen station has an LN2 generation facility and generates surplus LN2 in the storage tank, it can be released into a gas or liquid based turbine or a certain propeller or equivalent fluid interaction device and spin a generator or equivalent for power generation when expanding to return to GN2. This electricity is then used in many possible ways such as further electrical storage or conditioning etc. through batteries, capacitors, supercapacitors, and / or SMES, operating devices and equipment, and / or directly back to the power line or after holding electrical storage and sending etc.

[0076] (Power Conditioning System with High-Frequency Transformer) It is a high-speed switching transformer and a power conditioning system (PCS). One embodiment is a PCS designed to assist with lower eddy current losses on electrical machines for applications such as mobile platforms like electric aircraft. One embodiment of such a PCS is designed to assist a high-frequency Xfmr including embodiments of 3D printed cores to assist with more advanced requirements such as high-frequency switching operations.

[0077] (Power adjustment system with cryogen cooling of switchgear) For switching components and cryogen cooling on the same backplane. The high switching speed with the thermal benefits of the cryogen here leads to much more compact and higher power PCSs.

[0078] Accordingly, one aspect of some embodiments of the present invention is to provide a superconducting fault current limiter, the superconducting fault current limiter comprising a core adapted to receive a cryogen, at least one superconducting primary coil positioned around the core and having an upper edge and a lower edge, at least one superconducting secondary coil positioned around the core and having an upper edge and a lower edge, the at least one superconducting secondary coil being positioned adjacent to the superconducting primary coil, a primary coil positioned adjacent to the at least one superconducting primary coil and the at least one superconducting secondary coil, a power input interconnected to at least one of the superconducting primary coil, the superconducting secondary coil, and the primary coil, a power output interconnected to at least one of the superconducting primary coil, the superconducting secondary coil, and the primary coil, and a shunt for selectively interconnecting the power input to the power output.

[0079] Another aspect of some embodiments of the present invention is to provide a superconducting fault current limiter, which includes a core adapted to receive a cryogen, at least one superconducting primary coil positioned around the core and having an upper edge and a lower edge, at least one superconducting secondary coil positioned around the core and having an upper edge and a lower edge, wherein the at least one superconducting secondary coil is positioned adjacent to the superconducting primary coil, a primary coil positioned adjacent to the at least one superconducting primary coil and the at least one superconducting secondary coil, a power input interconnected to at least one of the superconducting primary coil, the superconducting secondary coil, and the primary coil, a power output interconnected to at least one of the superconducting primary coil, the superconducting secondary coil, and the primary coil, and a shunt for selectively interconnecting the power input to the power output, and the hollow portion or the thermally conductive path portion of the core is configured to receive the cryogen.

[0080] Another aspect of some embodiments of the present invention is to provide a superconducting fault current limiter, which includes a core adapted to receive a cryogen, at least one superconducting primary coil positioned around the core and having an upper edge and a lower edge, at least one superconducting secondary coil positioned around the core and having an upper edge and a lower edge, wherein the at least one superconducting secondary coil is positioned adjacent to the superconducting primary coil, a primary coil positioned adjacent to the at least one superconducting primary coil and the at least one superconducting secondary coil, a power input interconnected to at least one of the superconducting primary coil, the superconducting secondary coil, and the primary coil, a power output interconnected to at least one of the superconducting primary coil, the superconducting secondary coil, and the primary coil, and a shunt for selectively interconnecting the power input to the power output, and the primary coil is made of a conventional conductor.

[0081] Another aspect of some embodiments of the present invention is to provide a superconducting fault current limiter, the superconducting fault current limiter comprising a core adapted to receive a cryogen, at least one superconducting primary coil positioned around the core and having an upper edge and a lower edge, at least one superconducting secondary coil positioned around the core and having an upper edge and a lower edge, wherein the at least one superconducting secondary coil is positioned adjacent to the superconducting primary coil, a primary coil positioned adjacent to the at least one superconducting primary coil and the at least one superconducting secondary coil, a power input interconnected to at least one of the superconducting primary coil, the superconducting secondary coil, and the primary coil, a power output interconnected to at least one of the superconducting primary coil, the superconducting secondary coil, and the primary coil, and a shunt for selectively interconnecting the power input to the power output, wherein the superconducting primary and secondary coils are formed from wound high temperature superconducting tape, and the primary coil is made of copper.

[0082] Another aspect of some embodiments of the present invention is to provide a superconducting fault current limiter, the superconducting fault current limiter comprising a core adapted to receive a cryogen, at least one superconducting primary coil positioned around the core and having an upper edge and a lower edge, at least one superconducting secondary coil positioned around the core and having an upper edge and a lower edge, wherein the at least one superconducting secondary coil is positioned adjacent to the superconducting primary coil, a primary coil positioned adjacent to the at least one superconducting primary coil and the at least one superconducting secondary coil, a power input interconnected to at least one of the superconducting primary coil, the superconducting secondary coil, and the primary coil, a power output interconnected to at least one of the superconducting primary coil, the superconducting secondary coil, and the primary coil, and a shunt for selectively interconnecting the power input to the power output, wherein the superconducting primary and secondary coils are thin magnets formed from wound high temperature superconducting tape having a rectangular outer shape.

[0083] Another aspect of some embodiments of the present invention is to provide a superconducting fault current limiter, which includes a core adapted to receive a cryogen, at least one superconducting primary coil positioned around the core and having an upper edge and a lower edge, at least one superconducting secondary coil positioned around the core and having an upper edge and a lower edge, wherein the at least one superconducting secondary coil is positioned adjacent to the superconducting primary coil, a primary coil positioned adjacent to the at least one superconducting primary coil and the at least one superconducting secondary coil, a power input interconnected to at least one of the superconducting primary coil, the superconducting secondary coil, and the primary coil, a power output interconnected to at least one of the superconducting primary coil, the superconducting secondary coil, and the primary coil, and a shunt for selectively interconnecting the power input to the power output, and the shunt is a superconducting tape or cable.

[0084] Another aspect of some embodiments of the present invention is to provide a superconducting fault current limiter, which includes a core adapted to receive a cryogen, at least one superconducting primary coil positioned around the core and having an upper edge and a lower edge, at least one superconducting secondary coil positioned around the core and having an upper edge and a lower edge, wherein the at least one superconducting secondary coil is positioned adjacent to the superconducting primary coil, a primary coil positioned adjacent to the at least one superconducting primary coil and the at least one superconducting secondary coil, a power input interconnected to at least one of the superconducting primary coil, the superconducting secondary coil, and the primary coil, a power output interconnected to at least one of the superconducting primary coil, the superconducting secondary coil, and the primary coil, and a shunt for selectively interconnecting the power input to the power output, and the at least one superconducting primary coil is composed of a plurality of layers, each layer having an upper edge and / or a lower edge that does not correspond to the upper and / or lower edges of the adjacent layer, and it defines a pancake winding consisting of a curved or tapered winding pattern.

[0085] Another aspect of some embodiments of the present invention is to provide a superconducting fault current limiter, the superconducting fault current limiter comprising a core adapted to receive a cryogen, at least one superconducting primary coil positioned around the core and having an upper edge and a lower edge, at least one superconducting secondary coil positioned around the core and having an upper edge and a lower edge, the at least one superconducting secondary coil being positioned adjacent to the superconducting primary coil, a primary coil positioned adjacent to the at least one superconducting primary coil and the at least one superconducting secondary coil, a power input interconnected to at least one of the superconducting primary coil, the superconducting secondary coil, and the primary coil, a power output interconnected to at least one of the superconducting primary coil, the superconducting secondary coil, and the primary coil, and a shunt for selectively interconnecting the power input to the power output, the at least one superconducting primary coil defining a solenoid, the solenoid defining a solenoid axis corresponding to the magnetic field of the solenoid, the magnetic field of the solenoid generally extending from the upper edge to the lower edge of the at least one superconducting primary coil along the length of the solenoid, the superconducting primary coil being formed from a wound high temperature superconducting tape having a rectangular cross-section, the tape width being aligned with the solenoid axis.

[0086] Another aspect of some embodiments of the present invention is to provide a superconducting fault current limiter, the superconducting fault current limiter comprising: a core adapted to receive a cryogen; at least one superconducting primary coil positioned around the core and having an upper edge and a lower edge; at least one superconducting secondary coil positioned around the core and having an upper edge and a lower edge, the at least one superconducting secondary coil being positioned adjacent to the superconducting primary coil; a primary coil positioned adjacent to the at least one superconducting primary coil and the at least one superconducting secondary coil; a power input interconnected to at least one of the superconducting primary coil, the superconducting secondary coil, and the primary coil; a power output interconnected to at least one of the superconducting primary coil, the superconducting secondary coil, and the primary coil; and a shunt for selectively interconnecting the power input to the power output, wherein the at least one superconducting primary coil defines a solenoid, the solenoid defines a solenoid axis corresponding to the magnetic field of the solenoid, and the magnetic field of the solenoid generally extends from the upper edge to the lower edge of the at least one superconducting primary coil along the length of the solenoid, the superconducting primary coil is formed from a wound high temperature superconducting tape having a rectangular cross-section, the tape width is aligned with the solenoid axis, and the tape is installed such that its width is parallel to the maximum magnetic flux generated by the solenoid.

[0087] Another aspect of some embodiments of the present invention is to provide a superconducting fault current limiter, the superconducting fault current limiter comprising a core adapted to receive a cryogen, at least one superconducting primary coil positioned around the core and having an upper edge and a lower edge, at least one superconducting secondary coil positioned around the core and having an upper edge and a lower edge, wherein the at least one superconducting secondary coil is positioned adjacent to the superconducting primary coil, a primary coil positioned adjacent to at least one superconducting primary coil and at least one superconducting secondary coil, a power input interconnected to at least one of the superconducting primary coil, the superconducting secondary coil, and the primary coil, a power output interconnected to at least one of the superconducting primary coil, the superconducting secondary coil, and the primary coil, and a shunt for selectively interconnecting the power input to the power output, and the core is interconnected to a cryogen source configured to continuously or periodically receive a cryogen for maintaining the temperature of at least one of the superconducting primary coil, the superconducting secondary coil, and the primary coil below a predetermined temperature.

[0088] Another aspect of some embodiments of the present invention is to provide a superconducting fault current limiter, the superconducting fault current limiter comprising a core adapted to receive a cryogen, at least one superconducting primary coil positioned around the core and having an upper edge and a lower edge, at least one superconducting secondary coil positioned around the core and having an upper edge and a lower edge, wherein the at least one superconducting secondary coil is positioned adjacent to the superconducting primary coil, a primary coil positioned adjacent to at least one superconducting primary coil and at least one superconducting secondary coil, a power input interconnected to at least one of the superconducting primary coil, the superconducting secondary coil, and the primary coil, a power output interconnected to at least one of the superconducting primary coil, the superconducting secondary coil, and the primary coil, and a shunt for selectively interconnecting the power input to the power output, and the core is a cryogen reservoir and further comprises a cryocooler in thermal communication with the reservoir.

[0089] Another aspect of some embodiments of the present invention is to provide a superconducting fault current limiter, the superconducting fault current limiter comprising: a core adapted to receive a cryogen; at least one superconducting primary coil positioned around the core and having an upper edge and a lower edge; at least one superconducting secondary coil positioned around the core and having an upper edge and a lower edge, the at least one superconducting secondary coil being positioned adjacent to the superconducting primary coil; a primary coil positioned adjacent to the at least one superconducting primary coil and the at least one superconducting secondary coil; a power input interconnected to at least one of the superconducting primary coil, the superconducting secondary coil, and the primary coil; a power output interconnected to at least one of the superconducting primary coil, the superconducting secondary coil, and the primary coil; and a shunt for selectively interconnecting the power input to the power output, wherein the core is a cryogen reservoir and further comprises a cryocooler in thermal communication with the reservoir, and the core comprises at least partially the cryocooler.

[0090] Another aspect of some embodiments of the present invention is to provide a superconducting fault current limiter, the superconducting fault current limiter comprising: a core adapted to receive a cryogen; at least one superconducting primary coil positioned around the core and having an upper edge and a lower edge; at least one superconducting secondary coil positioned around the core and having an upper edge and a lower edge, the at least one superconducting secondary coil being positioned adjacent to the superconducting primary coil; a primary coil positioned adjacent to the at least one superconducting primary coil and the at least one superconducting secondary coil; a power input interconnected to at least one of the superconducting primary coil, the superconducting secondary coil, and the primary coil; a power output interconnected to at least one of the superconducting primary coil, the superconducting secondary coil, and the primary coil; and a shunt for selectively interconnecting the power input to the power output, the shunt being a superconducting tape or cable, wherein the superconducting primary coil, the superconducting secondary coil, and the primary coil define a combined inductive and resistive type superconducting FCL.

[0091] Another aspect of some embodiments of the present invention is to provide a superconducting fault current limiter, the superconducting fault current limiter comprising: a core adapted to receive a cryogen; at least one superconducting primary coil positioned around the core and having an upper edge and a lower edge; at least one superconducting secondary coil positioned around the core and having an upper edge and a lower edge, the at least one superconducting secondary coil being positioned adjacent to the superconducting primary coil; a primary coil positioned adjacent to the at least one superconducting primary coil and the at least one superconducting secondary coil; a power input interconnected to at least one of the superconducting primary coil, the superconducting secondary coil, and the primary coil; a power output interconnected to at least one of the superconducting primary coil, the superconducting secondary coil, and the primary coil; and a shunt for selectively interconnecting the power input to the power output, the shunt being a superconducting tape or cable, and the plurality of operating modes provided being associated with a mode 0 associated with a normal AC function characterized mainly by a main current present in the shunt, a mode 1 that occurs when the main current exceeds a predetermined level, quenches the shunt, shifts the main current to the superconducting primary coil, and induces a secondary current in the superconducting secondary coil, a mode 2 that occurs when the superconducting secondary coil quenches and shifts the main current to the superconducting primary coil, and a mode 3 that occurs when the superconducting primary coil, the superconducting secondary coil, and the shunt are quenched and shifts the main current to the primary coil.

[0092] Another aspect of some embodiments of the present invention is to provide a superconducting fault current limiter, the superconducting fault current limiter comprising: a core adapted to receive a cryogen; at least one superconducting primary coil positioned around the core and having an upper edge and a lower edge; at least one superconducting secondary coil positioned around the core and having an upper edge and a lower edge, wherein the at least one superconducting secondary coil is positioned adjacent to the superconducting primary coil; a primary coil positioned adjacent to the at least one superconducting primary coil and the at least one superconducting secondary coil; a power input interconnected to at least one of the superconducting primary coil, the superconducting secondary coil, and the primary coil; a power output interconnected to at least one of the superconducting primary coil, the superconducting secondary coil, and the primary coil; and a shunt for selectively interconnecting the power input to the power output, the shunt being a superconducting tape or cable, the plurality of operating modes provided being associated with mode 0 associated with a normal AC function characterized mainly by the main current present in the shunt, mode 1 which occurs when the main current exceeds a predetermined level, quenches the shunt, shifts the main current to the superconducting primary coil, and induces a secondary current in the superconducting secondary coil, mode 2 which occurs when the superconducting secondary coil quenches and shifts the main current to the superconducting primary coil, and mode 3 which occurs when the superconducting primary coil, the superconducting secondary coil, and the shunt are quenched and shifts the main current to the primary coil, and further comprising a primary reactive power compensator configured to compensate for a predetermined impedance.

[0093] Another aspect of some embodiments of the present invention is to provide a superconducting fault current limiter, the superconducting fault current limiter comprising a core adapted to receive a cryogen, at least one superconducting primary coil positioned around the core and having an upper edge and a lower edge, at least one superconducting secondary coil positioned around the core and having an upper edge and a lower edge, the at least one superconducting secondary coil being positioned adjacent to the superconducting primary coil, a primary coil positioned adjacent to the at least one superconducting primary coil and the at least one superconducting secondary coil, a power input interconnected to at least one of the superconducting primary coil, the superconducting secondary coil, and the primary coil, a power output interconnected to at least one of the superconducting primary coil, the superconducting secondary coil, and the primary coil, and a shunt for selectively interconnecting the power input to the power output, the shunt being a superconducting tape or cable, the plurality of operating modes provided being associated with a mode 0 associated with a normal AC function characterized mainly by a main current present in the shunt, a mode 1 that occurs when the main current exceeds a predetermined level, quenches the shunt, shifts the main current to the superconducting primary coil, and induces a secondary current in the superconducting secondary coil, a mode 2 that occurs when the superconducting secondary coil quenches and shifts the main current to the superconducting primary coil, and a mode 3 that occurs when the superconducting primary coil, the superconducting secondary coil, and the shunt are quenched and shifts the main current to the primary coil, in mode 1, the superconducting secondary coil generates a magnetic flux exclusion that isolates the superconducting primary coil.

[0094] Another aspect of some embodiments of the present invention is to provide a superconducting fault current limiter, the superconducting fault current limiter comprising a core adapted to receive a cryogen, at least one superconducting primary coil positioned around the core and having an upper edge and a lower edge, at least one superconducting secondary coil positioned around the core and having an upper edge and a lower edge, the at least one superconducting secondary coil being positioned adjacent to the superconducting primary coil, a primary coil positioned adjacent to the at least one superconducting primary coil and the at least one superconducting secondary coil, a power input interconnected to at least one of the superconducting primary coil, the superconducting secondary coil, and the primary coil, a power output interconnected to at least one of the superconducting primary coil, the superconducting secondary coil, and the primary coil, and a shunt for selectively interconnecting the power input to the power output, the shunt being a superconducting tape or cable, the plurality of operating modes provided being associated with mode 0 related to a normal AC function characterized mainly by a main current present in the shunt, mode 1 which occurs when the main current exceeds a predetermined level, quenches the shunt, shifts the main current to the superconducting primary coil, and induces a secondary current in the superconducting secondary coil, mode 2 which occurs when the superconducting secondary coil quenches and shifts the main current to the superconducting primary coil, and mode 3 which occurs when the superconducting primary coil, the superconducting secondary coil, and the shunt are quenched and shifts the main current to the primary coil. In mode 1, the superconducting secondary coil generates a magnetic flux exclusion that isolates the superconducting primary coil, and further comprises a secondary end shield positioned adjacent to the upper edge or the lower edge of the superconducting secondary coil, the secondary end shield being configured to isolate the primary coil.

[0095] Another aspect of some embodiments of the present invention is to provide a superconducting fault current limiter, the superconducting fault current limiter comprising a core adapted to receive a cryogen, at least one superconducting primary coil positioned around the core and having an upper edge and a lower edge, at least one superconducting secondary coil positioned around the core and having an upper edge and a lower edge, the at least one superconducting secondary coil being positioned adjacent to the superconducting primary coil, a primary coil positioned adjacent to the at least one superconducting primary coil and the at least one superconducting secondary coil, a power input interconnected to at least one of the superconducting primary coil, the superconducting secondary coil, and the primary coil, a power output interconnected to at least one of the superconducting primary coil, the superconducting secondary coil, and the primary coil, and a shunt for selectively interconnecting the power input to the power output, the shunt being a superconducting tape or cable, the plurality of operating modes provided being associated with a mode 0 associated with a normal AC function characterized mainly by a main current present in the shunt, a mode 1 which occurs when the main current exceeds a predetermined level, quenches the shunt, shifts the main current to the superconducting primary coil, and induces a secondary current in the superconducting secondary coil, a mode 2 which occurs when the superconducting secondary coil quenches and shifts the main current to the superconducting primary coil, and a mode 3 which occurs when the superconducting primary coil, the superconducting secondary coil, and the shunt are quenched and shifts the main current to the primary coil, in mode 1, the superconducting primary coil operates with the reactance of the primary coil which is mostly inductive.

[0096] Another aspect of some embodiments of the present invention is to provide a superconducting fault current limiter, the superconducting fault current limiter comprising: a core adapted to receive a cryogen; at least one superconducting primary coil positioned around the core and having an upper edge and a lower edge; at least one superconducting secondary coil positioned around the core and having an upper edge and a lower edge, wherein the at least one superconducting secondary coil is positioned adjacent to the superconducting primary coil; a primary coil positioned adjacent to the at least one superconducting primary coil and the at least one superconducting secondary coil; a power input interconnected to at least one of the superconducting primary coil, the superconducting secondary coil, and the primary coil; a power output interconnected to at least one of the superconducting primary coil, the superconducting secondary coil, and the primary coil; and a shunt for selectively interconnecting the power input to the power output, the shunt being a superconducting tape or cable, and the plurality of operating modes provided are associated with a mode 0 associated with a normal AC function characterized mainly by a main current present in the shunt, a mode 1 that occurs when the main current exceeds a predetermined level, quenches the shunt, shifts the main current to the superconducting primary coil, and induces a secondary current in the superconducting secondary coil, a mode 2 that occurs when the superconducting secondary coil quenches and shifts the main current to the superconducting primary coil, and a mode 3 that occurs when the superconducting primary coil, the superconducting secondary coil, and the shunt are quenched and shifts the main current to the primary coil. In mode 1, all partial power design faults are removed within a partial cycle.

[0097] Another aspect of some embodiments of the present invention is to provide a superconducting fault current limiter, the superconducting fault current limiter comprising a core adapted to receive a cryogen, at least one superconducting primary coil positioned around the core and having an upper edge and a lower edge, at least one superconducting secondary coil positioned around the core and having an upper edge and a lower edge, the at least one superconducting secondary coil being positioned adjacent to the superconducting primary coil, a primary coil positioned adjacent to the at least one superconducting primary coil and the at least one superconducting secondary coil, a power input interconnected to at least one of the superconducting primary coil, the superconducting secondary coil, and the primary coil, a power output interconnected to at least one of the superconducting primary coil, the superconducting secondary coil, and the primary coil, and a shunt for selectively interconnecting the power input to the power output, the shunt being a superconducting tape or cable, and the plurality of operating modes provided being associated with a mode 0 associated with a normal AC function characterized mainly by a main current present in the shunt, a mode 1 that occurs when the main current exceeds a predetermined level, quenches the shunt, shifts the main current to the superconducting primary coil, and induces a secondary current in the superconducting secondary coil, a mode 2 that occurs when the superconducting secondary coil quenches and shifts the main current to the superconducting primary coil, and a mode 3 that occurs when the superconducting primary coil, the superconducting secondary coil, and the shunt are quenched and shifts the main current to the primary coil, and in mode 2, the superconducting secondary coil generates a high resistance.

[0098] Another aspect of some embodiments of the present invention is to provide a superconducting fault current limiter, the superconducting fault current limiter comprising a core adapted to receive a cryogen, at least one superconducting primary coil positioned around the core and having an upper edge and a lower edge, at least one superconducting secondary coil positioned around the core and having an upper edge and a lower edge, the at least one superconducting secondary coil being positioned adjacent to the superconducting primary coil, a primary coil positioned adjacent to the at least one superconducting primary coil and the at least one superconducting secondary coil, a power input interconnected to at least one of the superconducting primary coil, the superconducting secondary coil, and the primary coil, a power output interconnected to at least one of the superconducting primary coil, the superconducting secondary coil, and the primary coil, and a shunt for selectively interconnecting the power input to the power output, the shunt being a superconducting tape or cable, the plurality of operating modes provided being associated with a mode 0 associated with a normal AC function characterized mainly by a main current present in the shunt, a mode 1 that occurs when the main current exceeds a predetermined level, quenches the shunt, shifts the main current to the superconducting primary coil, and induces a secondary current in the superconducting secondary coil, a mode 2 that occurs when the superconducting secondary coil quenches and shifts the main current to the superconducting primary coil, and a mode 3 that occurs when the superconducting primary coil, the superconducting secondary coil, and the shunt are quenched and shifts the main current to the primary coil, at least one superconducting primary coil being composed of a plurality of layers, and in mode 2, the layers are magnetically connected to increase the primary mutual inductance.

[0099] Another aspect of some embodiments of the present invention is to provide a superconducting fault current limiter, the superconducting fault current limiter comprising a core adapted to receive a cryogen, at least one superconducting primary coil positioned around the core and having an upper edge and a lower edge, at least one superconducting secondary coil positioned around the core and having an upper edge and a lower edge, the at least one superconducting secondary coil being positioned adjacent to the superconducting primary coil, a primary coil positioned adjacent to the at least one superconducting primary coil and the at least one superconducting secondary coil, a power input interconnected to at least one of the superconducting primary coil, the superconducting secondary coil, and the primary coil, a power output interconnected to at least one of the superconducting primary coil, the superconducting secondary coil, and the primary coil, and a shunt for selectively interconnecting the power input to the power output, the shunt being a superconducting tape or cable, the plurality of operating modes provided being associated with mode 0 associated with a normal AC function characterized mainly by a main current present in the shunt, mode 1 which occurs when the main current exceeds a predetermined level, quenches the shunt, shifts the main current to the superconducting primary coil, and induces a secondary current in the superconducting secondary coil, mode 2 which occurs when the superconducting secondary coil quenches and shifts the main current to the superconducting primary coil, and mode 3 which occurs when the superconducting primary coil, the superconducting secondary coil, and the shunt are quenched and shifts the main current to the primary coil, in mode 3, the superconducting primary side generates a high resistance, which sends all the current to the quenched superconducting and non-superconducting coils.

[0100] Another aspect of some embodiments of the present invention is to provide a superconducting fault current limiter, which includes a core adapted to receive a cryogen, at least one superconducting primary coil positioned around the core and having an upper edge and a lower edge, at least one superconducting secondary coil positioned around the core and having an upper edge and a lower edge, wherein the at least one superconducting secondary coil is positioned adjacent to the superconducting primary coil, a primary coil positioned adjacent to at least one superconducting primary coil and at least one superconducting secondary coil, a power input interconnected to at least one of the superconducting primary coil, the superconducting secondary coil, and the primary coil, a power output interconnected to at least one of the superconducting primary coil, the superconducting secondary coil, and the primary coil, and a shunt for selectively interconnecting the power input to the power output. The superconducting secondary coil is formed of a non-insulated superconducting tape or cable with a layer wound around a conventional conductor, and the conventional conductor is wound in the middle portion of the superconducting secondary coil.

[0101] Another aspect of some embodiments of the present invention is to provide a superconducting fault current limiter, which includes a core adapted to receive a cryogen, at least one superconducting primary coil positioned around the core and having an upper edge and a lower edge, at least one superconducting secondary coil positioned around the core and having an upper edge and a lower edge, wherein the at least one superconducting secondary coil is positioned adjacent to the superconducting primary coil, a primary coil positioned adjacent to at least one superconducting primary coil and at least one superconducting secondary coil, a power input interconnected to at least one of the superconducting primary coil, the superconducting secondary coil, and the primary coil, a power output interconnected to at least one of the superconducting primary coil, the superconducting secondary coil, and the primary coil, and a shunt for selectively interconnecting the power input to the power output. The superconducting primary and secondary coils are formed of a wound high-temperature superconducting tape having a rectangular outer shape.

[0102] Another aspect of some embodiments of the present invention is to provide a superconducting fault current limiter, the superconducting fault current limiter comprising: a core adapted to receive a cryogen; at least one superconducting primary coil positioned around the core and having an upper edge and a lower edge; at least one superconducting secondary coil positioned around the core and having an upper edge and a lower edge, the at least one superconducting secondary coil being positioned adjacent to the superconducting primary coil; a primary coil positioned adjacent to the at least one superconducting primary coil and the at least one superconducting secondary coil; a power input interconnected to at least one of the superconducting primary coil, the superconducting secondary coil, and the primary coil; a power output interconnected to at least one of the superconducting primary coil, the superconducting secondary coil, and the primary coil; and a shunt for selectively interconnecting the power input to the power output, wherein the primary and superconducting secondary coils are made of superconducting tape or cable.

[0103] Yet another aspect of some embodiments of the present invention is to provide a method for dealing with faults in a power grid, the method including providing a superconducting fault current limiter, the superconducting fault current limiter including a core adapted to receive a cryogen, at least one superconducting primary coil positioned around the core and having an upper edge and a lower edge, at least one superconducting secondary coil positioned around the core and having an upper edge and a lower edge, the at least one superconducting secondary coil being positioned adjacent to the superconducting primary coil, a primary coil positioned adjacent to the at least one superconducting primary coil and the at least one superconducting secondary coil, a power input interconnected to at least one of the superconducting primary coil, the superconducting secondary coil, and the primary coil, a power output interconnected to at least one of the superconducting primary coil, the superconducting secondary coil, and the primary coil, and a shunt including a superconducting cable selectively interconnecting the power input to the power output, the shunt being a superconducting tape or cable, and the plurality of operating modes provided including passing a main current through the shunt until the main current exceeds a predetermined level, shifting the main current to the superconducting primary coil and inducing a secondary current in the superconducting secondary coil when the main current exceeds the predetermined level, shifting the main current to the superconducting primary coil when the superconducting secondary coil quenches, and shifting the main current to the Cu primary side when the superconducting primary coil, the superconducting secondary coil, and the shunt are quenched.

[0104] Another aspect of some embodiments of the present invention is to provide an electrical transformer, which includes a primary magnet coil, a secondary magnet coil adjacent to the primary magnet coil, a superconducting primary magnet coil, and a superconducting secondary magnet coil. The primary magnet coil, secondary magnet coil, superconducting primary magnet coil, and superconducting secondary magnet coil are surrounded by a housing such that the inner surface of the primary magnet coil defines an internal volume. The electrical transformer further includes a power input interconnected to at least one of the primary magnet coil, secondary magnet coil, superconducting primary magnet coil, and superconducting secondary magnet coil, and a power output interconnected to at least one of the primary magnet coil, secondary magnet coil, superconducting primary magnet coil, and superconducting secondary magnet coil.

[0105] The summary of the invention is not intended, nor should it be construed, to represent the full scope and range of the present invention. That is, these and other aspects and advantages will become apparent from the disclosure of the present invention described herein. Further, the embodiments, aspects, objects, and configurations described above are not complete or exhaustive. As will be understood, other embodiments of the present invention are possible using one or more than one of the features described above or below, alone or in combination. Also, references herein to "the present invention" or aspects thereof should be understood to mean an embodiment of the present invention and should not necessarily be construed to limit all embodiments to a particular description. The present invention is described in various levels of detail in the summary of the invention as well as the accompanying drawings and detailed description, and any limitation regarding the scope of the present invention is not intended by either the inclusion or non-inclusion of elements, components, etc. in the summary of the invention. Additional aspects of the present invention will be more readily apparent from the detailed description when considered particularly in conjunction with the drawings.

[0106] The benefits, embodiments, and / or characterizations described above are not necessarily complete or exhaustive, particularly with respect to the patentable subject matter disclosed herein. Other benefits, embodiments, and / or characterizations of the present invention are possible, alone or in combination, using those described above and / or illustrated in the accompanying figures and / or described in the following specification of the present application.

[0107] The phrases "at least one", "one or more", and "and / or" as used herein are non-restrictive expressions that are both conjunctive and disjunctive in operation. For example, each of the expressions "at least one of A, B, and C", "at least one of A, B, or C", "one or more of A, B, and C", "one or more of A, B, or C", and "A, B, and / or C" means only A, only B, only C, both A and B together, both A and C together, both B and C together, or all of A, B, and C together.

[0108] Unless otherwise indicated, all numbers expressing quantities, dimensions, conditions, etc. used in this specification and in the figures of the drawings are to be understood as approximate values that may be modified in all instances as required for the particular application of the novel assemblies and methods described herein.

[0109] The term "a" or "an" entity as used herein refers to one or more of that entity. Thus, the terms "a" (or "an"), "one or more", and "at least one" can be used synonymously herein.

[0110] The use of "comprising", "having", or "including" in this specification, and variations thereof, means including the items listed hereinafter and their equivalents and additional items. Thus, the terms "comprising", "having", or "including", and variations thereof, can be used synonymously.

[0111] It should be understood that the term "means" as used in this specification is to be given its broadest possible interpretation in accordance with 35 U.S.C., Section 112(f). Thus, claims incorporating the term "means" are intended to cover all structures, materials, or acts described herein, and all equivalents thereof. Further, structures, materials, or acts, and their equivalents, are intended to include all those described in the summary, brief description of the drawings, detailed description, and the figures of the accompanying drawings.

Brief Description of the Drawings

[0112] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the general description of the invention given above and the detailed description of the drawings given below, serve to explain the principles of these inventions.

[0113]

Figure 1

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Figure 2

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Figure 3

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Figure 3A

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Figure 4

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Figure 5

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Figure 6

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Figure 7

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Figure 8A

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Figure 8B

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Figure 8C

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Figure 8D

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Figure 9A

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Figure 9B

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Figure 9C

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Figure 10

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Figure 11

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Figure 12

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Figure 13

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Figure 16A

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Figure 16B

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Figure 16C

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Figure 17A

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Figure 17B

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Figure 17C

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Figure 17D

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Figure 18A

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Figure 18B

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Figure 18C

DETAILED DESCRIPTION OF THE INVENTION

[0144] The following list of components and the associated reference numerals found in the drawings are provided to assist in the understanding of one embodiment of the present invention.

Table 1

[0145] It should be understood that the drawings are not necessarily to scale. In some cases, details that are not necessary for understanding the present invention or that make it difficult to grasp other details may be omitted. Of course, it should be understood that the present invention is not necessarily limited to the specific embodiments illustrated herein.

[0146] (Fault current limiter)

[0147] FIG. 1-9c shows a superconducting fault current limiter (FCL) 2 of an embodiment of the present invention that employs a stepped power handling methodology. The FCL 2 comprises at least one SC primary coil 4 surrounded by or meshed with an SC secondary coil 8. The SC secondary coil 8 can be characterized by a winding angle 20 (see FIGS. 3a and 7b). In one embodiment, the winding angle 20 is formed by providing an SC tape winding, resulting in various heights as shown in FIG. 3a. The coils 4, 8 are separated by a G10 electrical insulation layer 10, surrounded by a Cu primary coil 12, and the assembly of coils 4, 8, 10, 12 is installed in a housing 18 that also houses an end shield 24.

[0148] The housing also houses the HTS shunt 50 and the terminal 34 for interconnecting to the power grid. The housing can also house the cryogen reservoir 36 that can also function as a core. The cryogen reservoir is filled by the cryogen port 38. The FCL can be cooled by the cryo cooler 40, which has a cryogen port 42 connected to a compressor. The cryo cooler is configured to circulate a cryogen that keeps the cryogen in the reservoir at a predetermined temperature. During operation, when a fault is removed, the staged design provides a faster recovery time since each stage recovers separately and can operate at each fault level. All FCL modes, as will be discussed below, use a nearly instantaneous recovery flux-flow SC FCL design that does not exceed the critical HTS transport current (except for temperature) during a fault, and the disadvantages of the general flux-flow that requires more HTS, the instantaneous current, B, and the appearance of the resistance dependence on temperature are removed when moving to the next stage.

[0149] To provide a high-power and compact inductive FCL, a plurality of concentric HTS layers of SC primary sides 4 and secondary sides 8 are wound together and operate in parallel. B needs to complete the loop, and thus, a full-length HTS secondary end shield 24 is set on one or both sides of each SC primary coil 4 to provide SC primary side B coil isolation. Due to HTS B exclusion, the SC secondary coils located radially and axially inside each SC primary coil prevent the main B of the SC primary concentric coils from connecting to itself, and the SC secondary coils on both sides of each SC primary coil prevent the SC primary coils from connecting to each other. Only the stray B of the SC primary coils remains as it is. Odd-numbered SC secondary coils are often reverse-connected to cancel out the emf of the even-numbered SC secondary coil pairs, but one odd-numbered coil is desired to remain as it is to induce a set current and achieve the desired quench profile. The SC secondary coil or group of coils also has a reverse current connection option from the SC primary side, reducing the SC primary side B operating limit within the SC secondary side B exclusion and induced B, and further reducing the common operating mutual inductance, response time, induced current, and associated AC losses. From the SC primary side to the SC primary side, there is no reverse current connection, and thus, a high fault mutual inductance is maintained. To increase the fault B coupling, B leakage is minimized by shortening the distance between the windings, but then the winding structure must adapt to the Lorentz force.

[0150] As mentioned above, some embodiments employ an HTS cable shunt 50 configured to short-circuit the entire FCL. The envisioned shunt enhances the safe SC FCL operation, reduces the grid burden, removes the normal operation impedance, thereby improving the FCL efficiency in a compact manner, counteracting the inductive FCL, and also reducing the fault time constant and critical clearing time (CCT) for low-inertia generators, and improving the fault power factor and stability. Without any faults, the HTS cable shunt allows for lossless passage up to the rated fault current. FCL mode 1 (Figure 8b, R / L fault mode, Z Shunt) In this case, the HTS cable quenches at 100% rated fault current. This initiates a constant and increasing energy dissipation fault response. Since the HTS cable shunt is a short circuit, the voltage drop during normal operation is clearly below the desired maximum of 5% of the FCL, the AC losses are minimized, and high substrate or preferably high critical superconducting zone propagation velocity (NZPV) HTS and Cu cores are used for HTS protection. Instead of using an HTS stack, an embedded FT cable can significantly reduce the inductance and AC losses, distribute the current uniformly, and the embedded FT cable can include a high twist angle to protect against Lorentz forces. If AC losses are still a concern, HTS opposing bifilar pancakes within the voltage limit are used.

[0151] Figures 8a and 9a show the FCL normal passive mode 0 operation (i.e., lossless operation without any quenches), where the HTS has no resistance and has negligible inductance and AC losses. Most of the current (I1) flows through the HTS shunt 50 in AC (Figure 8a), or through the HTS shunt 50 and the SC primary coil 4 (I1 and I2) in DC (Figure 9a). In AC, the B exclusion of the secondary shield shields the SC primary side and the Cu primary coil 12 from each other, which significantly reduces the inductance. This limits the SC primary side impedance to the winding leakage impedance. In DC, all the current follows the lowest resistance path with various levels of HTS quench and increasing Cu resistance without any inductance effect, eliminating the period of high transient current for each mode.

[0152] Figure 8b shows the operation in mode 1 (R / L fault mode), where the HTS cable quenches at 100% rated fault current. This initiates a constant and increasing energy dissipation fault response.

[0153] Figure 8c shows the FCL in mode 2 (L fault mode), where the secondary quenches at 175% rated fault current. This provides a rapid high fault impedance when the SC primary coils are connected to each other. The secondary substrate must be designed to handle all the induced current in this mode. All the inner SC secondary coils face two SC primary coil sources with respect to the outer SC secondary coil, and thus the inner SC secondary coils have approximately twice the turns, enabling a constant current transformer relationship. The parallel Cu primary windings wound with angular wires for a higher packing factor are outside the outermost secondary side for additional inductive fault impedance.

[0154] Figure 8d shows the FCL in mode 3 (L / R fault mode), where the SC primary quenches at 300% rated fault current and all the remaining fault energy proceeds to the Cu primary side up to an acceptable 600% rated fault current. The Cu primary side, with negligible power during normal operation, enters the SC primary resistive fault mode with a very high, increasing R and then L impedance. Different from entering the FCL mode 2 with a set inductance increase, the transition to the FCL mode 3 must consider sufficient Cu primary side impedance to handle the high input current regarding the set voltage for removing the thermal runaway situation. Each mode, especially mode 3, must have less impedance than the previous mode; otherwise, recovery will not occur. All the fault mode values are set through the FCL design and can be easily changed in some embodiments via the WRAP - M technique mentioned above by selectively modifying the manufacturing process.

[0155] It has been found that the secondary HTS stabilizer can be exposed to significant heating in Mode 2. One way to address this heating is to use a non-insulated HTS with a shorted Cu sheet wound in the middle of the secondary HTS. The HTS will eliminate any B heating in Mode 1. In Mode 3, the Cu sheet not only provides a large Cu area for current, but more importantly, in Mode 2, the sheet essentially turns the entire non-insulated secondary side into a single magnetic winding turn, which then removes the large induced emf and all associated heating.

[0156] Figures 9a-c show the operation of the FCL for DC applications, including inductive operation with high transient currents. For any period of high transient current, each operating mode will include its inductive fault response before proceeding to the next sequential mode.

[0157] Figures 10 - 11b show the solenoidal superconducting fault current limiting transformer 200 (FCL / Xfmr) of one embodiment of the present invention. The FCL Xfmr shown operates in a manner similar to the toroidal transformer described below and includes many of the features found in the FCL shown in Figures 1 - 7b. Here, the HTS Xfmr consisting of the SC primary coil 204 and the SC secondary coil 208 is surrounded by a Cu Xfmr consisting of a Cu primary coil 212 (and perhaps a Cu secondary coil as employed by the toroidal embodiment shown in Figure 13). An upper end shield 224 is also provided. Here, the reservoir is larger and the inner diameters of the coils 204, 208 are spaced from the outer diameter of the cryocooler 240. Those skilled in the art will understand that the reservoir of this embodiment can be made similar to that of Figures 1 and 2 without departing from the scope of the present invention.

[0158] FIG. 12-18c shows a full cryogenic HTS transformer 60. One embodiment consists of a single-phase or polyphase toroidal magnet assembly 64. The power capability is scalable by using optimally sized parallel (current) and series (voltage) toroidal segments stacked within a single cryostat with a common cryogenic system or a system of discrete toroids with one toroidal per phase. The phased toroids are separated into axial and radial magnet components for single-phase to polyphase multi-tap Xfmrs with overlapping or separable magnets. The segments are wound one-third for a 3-phase device, less than half of a toroid. Winding one-third enables a 3-phase constructed on a single toroid, requiring no splices within the magnet. Combining the windings and phases on a single toroid provides a more reliable unit from fewer components, reducing weight, size, capital, maintenance costs, and increasing efficiency (the high packing ratio toroidal B path is the most efficient of any geometry). The total B across all phases cancels due to phased sequencing, removing external Xfmr phased inductive crosstalk. The maximum unit size is determined by limitations such as soldering, heat, cost, EM shielding, etc. Due to the air-core design with no requirement for any Fe B continuity, all magnets are wound either all at once when forming the final device or in segments to be connected. Structurally, the toroid is held at the phase change location.

[0159] As shown in FIGS. 13-15, the toroid is evenly wound along the winding axis into one separate axial toroidal winding segment per phase, electrically phased, and radially separated into SC primary magnets 68 and secondary magnets 72 for each phase in each axial segment. The winding is enclosed within a housing 82 that also houses at least one terminal 84. The housing may also house a cryogen reservoir 36 that can also function as a core. The cryogen reservoir can be filled by a cryogen port 38. The FCL can be cooled by a cryocooler 40 with a cryogen port 42 connecting to a compressor.

[0160] As shown in FIG. 14, the Cu Xfmr consisting of the Cu primary magnet 74(2P) and the Cu secondary magnet 76(2S) is installed on the SC Xfmr (for example, adopting the primary side 68(1P) and the secondary side 72(1S)), and the phase-shifted secondary sides (S) are installed directly above their respective phase-shifted primary sides (P) to assist the induced secondary Xfmr action. The SC layer is used to radially separate each magnet by B. In this toroidal configuration, the Xfmr eliminates the outer Cu winding up to the quench, resulting in a very efficient Xfmr and a fast-acting FCL operation. The HTS B elimination minimizes the leakage B, which maintains B in the toroid for Xfmr action, shields each phase from the induced currents from other phases, and enables the FCL option. The SC secondary side (I 1S ) and the Cu primary and secondary sides (I 1P and I 2S ) are wound and connected such that the induced current and any leakage magnetic flux are added to the Xfmr action. Regarding any B that can escape from the inner toroid, the outer LN2-cooled Cu Xfmr toroidal phase winding captures that B with a slight resistance, but increases the overall efficiency by removing any possible leakage B.

[0161] The Xfmr shown in FIGS. 12 - 16c is configured to provide operating modes similar to those described above with respect to FIGS. 1 - 9c. Again, the Xfmr or a separate FCL within it must passively, but rapidly increase the impedance while safely controlling the high-power path, with respect to both current and voltage. During all modes, the toroidal FCL functions as an Xfmr.

[0162] FIGS. 17a - d depict a toroidal SC FCL Xfmr, where three separate toroids, each representing an option for an individual phase, are included within a single common cryostat for compactness and simplicity.

[0163] Figure 17c represents a single SC FCL Xfmr, with multiple (in this case, three) phases separated around the circumference of the toroid. Such a design enables a compact design with an efficient operational B path. When used in the three-stage configuration described in Figures 17a-d, the resulting toroidal SC FCL Xfmr assembly includes nine phases.

[0164] Figure 18a shows FCL mode 1 (L fault mode), where the HTS inductance removes low-energy faults exceeding 100% rated Xfmr operation (I 1P and I 1S ). This mode regulates the line by immediately operating to remove all partial power design faults.

[0165] FCL mode 2 (R / L fault mode) is shown in Figure 18b. First, the Xfmr side exceeding the HTS critical current (usually the high Xfmr current side) quenches at 50% rated maximum fault current. This electrically connects the Cu Xfmr side on that side (here I 2S ) to the non-quenched HTS Xfmr side (here I 1P ). This mode is set to remove all standard design faults within 1 / 4 cycle due to the nature of the resistive circuit increase and then recover within 0.1 second to several seconds depending on the secondary load.

[0166] Figure 18c shows FCL mode 3 (R / L fault mode), where next the Xfmr side exceeding the HTS critical current (usually the low Xfmr current side) quenches at 75% rated maximum fault current. This electrically connects both Cu Xfmr sides (I 2P and I 2S) is connected. At this point, the entire FCL is inefficient but powerful in limiting faults, and the HTS must be protected. The Cu is cryogenically cooled to assist in power interruption. The primary side of the Cu is initially at LN2 temperature, and the Cu in LN2 has about eight times the conductance. As the fault persists, the LN2 evaporates over time, thus significantly increasing the Cu resistance, which provides an optimal increasing variable resistance response. This mode is set to remove the fault within a few milliseconds and then recover within a few seconds depending on the load or within a few minutes for extreme fault cases beyond normal FCL specifications. Due to the high mode 3 current, after the LN2 level is reduced, in mode 3, the Cu coil rapidly heats up and there is a risk that the FCL will open circuit fail.

[0167] For the Xfmr FCL, the HTS stabilizer can receive significant inductive coupling and heating in modes 2 and 3. There are multiple solutions to address this situation. In one embodiment, a secondary inductive heating modification as described above can be used. Alternatively, a non-insulated HTS with a shorted Cu sheet wound in the middle of each HTS coil can be employed. The HTS will eliminate any B heating in mode 1. In modes 2 and 3, the Cu sheet provides a large Cu area for current, making the entire non-insulated secondary side into one turn, which then removes the large induced emf and all associated heating.

[0168] When the fault is removed, the stepped design provides a faster recovery time as each stage recovers separately and can operate at each fault level. All FCL modes use an almost instantaneous recovery flux-flow SC FCL design and do not exceed the critical HTS transport current (except for temperature) during a fault. The drawbacks of the general flux-flow that require more HTS and the resulting resistance dependencies on instantaneous current, B, and temperature are removed when moving to the next stage.

Claims

1. A superconducting fault current limiter, wherein the superconducting fault current limiter comprises: a core adapted to receive a cryogen; at least one superconducting primary coil positioned around the core and having an upper edge and a lower edge; at least one superconducting secondary coil positioned around the core and having an upper edge and a lower edge, wherein the at least one superconducting secondary coil is positioned adjacent to the superconducting primary coil; a primary coil positioned adjacent to the at least one superconducting primary coil and the at least one superconducting secondary coil; a power input interconnected to at least one of the superconducting primary coil, the superconducting secondary coil, and the primary coil; a power output interconnected to at least one of the superconducting primary coil, the superconducting secondary coil, and the primary coil; and a shunt for selectively interconnecting the power input to the power output. A superconducting fault current limiter comprising the above.

2. The superconducting fault current limiter according to claim 1, wherein the hollow portion or the thermally conductive path portion of the core is configured to receive a cryogen.

3. The superconducting fault current limiter according to claim 1, wherein the primary coil is made of a conventional conductor.

4. The superconducting fault current limiter according to claim 1, wherein the superconducting primary and secondary coils are formed from wound high-temperature superconducting tapes, and the primary coil is made of copper.

5. The superconducting fault current limiter according to claim 1, wherein the superconducting primary and secondary coils are thin magnets formed from wound high-temperature superconducting tapes having a rectangular outer shape.

6. The superconducting fault current limiter according to claim 1, wherein the shunt is a superconducting tape or cable.

7. The superconducting fault current limiter according to claim 1, wherein the at least one superconducting primary coil comprises a plurality of layers, each layer having upper and / or lower edges that do not correspond to the upper and / or lower edges of adjacent layers, and which define a helical winding pattern of a helical winding consisting of a curved or tapered winding pattern.

8. The at least one superconducting primary coil defines a solenoid, the solenoid defines a solenoid axis corresponding to the magnetic field of the solenoid, the magnetic field of the solenoid generally extends from the upper edge to the lower edge of the at least one superconducting primary coil along the length of the solenoid, the superconducting primary coil is formed from a wound high-temperature superconducting tape having a rectangular cross-section, and the tape width is aligned with the solenoid axis. The superconducting fault current limiter according to claim 1.

9. The superconducting fault current limiter according to claim 8, wherein the tape is installed such that its width is parallel to the maximum magnetic flux generated by the solenoid.

10. The core is interconnected to a cryogen source, and the cryogen source is configured to continuously or periodically receive cryogen for maintaining the temperature of at least one of the superconducting primary coil, the superconducting secondary coil, and the primary coil below a predetermined temperature. The superconducting fault current limiter according to claim 1.

11. The superconducting fault current limiter according to claim 1, wherein the core is a cryogen reservoir and further includes a cryocooler in thermal communication with the reservoir.

12. The superconducting fault current limiter according to claim 11, wherein the core consists at least partially of the cryocooler.

13. The shunt is a superconducting tape or cable, and the superconducting primary coil, the superconducting secondary coil, and the primary coil define a combined inductive and resistive type superconducting FCL. The superconducting fault current limiter according to claim 1.

14. The shunt is a superconducting tape or cable, and the plurality of operating modes provided are Mode 0 associated with normal AC function, wherein Mode 0 is characterized mainly by the main current present in the shunt, Mode 0, and Mode 1, which occurs when the main current exceeds a predetermined level, which quenches the shunt, which shifts the main current to the superconducting primary coil, which induces a secondary current in the superconducting secondary coil, Mode 1, and Mode 2, which occurs when the superconducting secondary coil quenches, which shifts the main current to the superconducting primary coil, Mode 2 Mode 3, wherein when the superconducting primary coil, the superconducting secondary coil, and the shunt are quenched, it occurs, which shifts the main current to the primary coil, Mode 3 The superconducting fault current limiter according to claim 1, comprising

15. The superconducting fault current limiter according to claim 14, further comprising a primary reactive power compensator configured to compensate for a predetermined impedance.

16. The superconducting fault current limiter according to claim 14, wherein in Mode 1, the superconducting secondary coil generates a magnetic flux exclusion that isolates the superconducting primary coil.

17. The superconducting fault current limiter according to claim 16, further comprising a secondary end shield positioned adjacent to an upper edge or a lower edge of the superconducting secondary coil, the secondary end shield being configured to isolate the primary coil.

18. The superconducting fault current limiter according to claim 14, wherein in Mode 1, the superconducting primary coil operates with the reactance of the primary coil, most of which is inductive.

19. The superconducting fault current limiter according to claim 14, wherein in Mode 1, all partial power design faults are removed within a partial cycle.

20. The superconducting fault current limiter according to claim 14, wherein in Mode 2, the superconducting secondary coil generates a high resistance.

21. The superconducting fault current limiter according to claim 14, wherein the at least one superconducting primary coil consists of a plurality of layers, and in Mode 2, the layers are magnetically connected to increase the primary mutual inductance.

22. The superconducting fault current limiter according to claim 14, wherein in Mode 3, the superconducting primary side generates a high resistance, which sends all currents to the quenched superconducting and non-superconducting coils.

23. The superconducting fault current limiter according to claim 1, wherein the superconducting secondary coil consists of a non-insulated superconducting tape or cable with a layer wound around a conventional conductor, and the conventional conductor is wound around an intermediate portion of the superconducting secondary coil.

24. The superconducting fault current limiter according to claim 1, wherein the superconducting primary and superconducting secondary coils are formed from wound high-temperature superconducting tapes having a rectangular outer shape.

25. The primary and superconducting secondary coils are the superconducting fault current limiter according to claim 1, which consists of a superconducting tape or cable.

26. A method for dealing with faults in a power grid, the method including providing a superconducting fault current limiter, the superconducting fault current limiter including a core adapted to receive a cryogen, at least one superconducting primary coil positioned around the core and having an upper edge and a lower edge, at least one superconducting secondary coil positioned around the core and having an upper edge and a lower edge, wherein the at least one superconducting secondary coil is positioned adjacent to the superconducting primary coil, a primary coil positioned adjacent to the at least one superconducting primary coil and the at least one superconducting secondary coil, a power input interconnected to at least one of the superconducting primary coil, the superconducting secondary coil, and the primary coil, a power output interconnected to at least one of the superconducting primary coil, the superconducting secondary coil, and the primary coil, and a shunt consisting of a superconducting cable for selectively interconnecting the power input to the power output and comprising, the shunt being a superconducting tape or cable, the plurality of operating modes provided being passing the main current through the shunt until the main current exceeds a predetermined level, when the main current exceeds the predetermined level, shifting the main current to the superconducting primary coil and inducing a secondary current in the superconducting secondary coil, when the superconducting secondary coil quenches, shifting the main current to the superconducting primary coil, and when the superconducting primary coil, superconducting secondary coil, and shunt are quenched, shifting the main current to the Cu primary side including, method.

27. The method according to claim 26, wherein the hollow portion or the thermally conductive path portion of the core is configured to receive a cryogen.

28. The method according to claim 26, wherein the primary coil consists of a conventional conductor.

29. The method according to claim 26, wherein the fault current limiter further comprises a primary reactive power compensator configured to compensate for a predetermined impedance.

30. The method according to claim 26, wherein the superconducting secondary coil generates a magnetic flux exclusion for isolating the superconducting primary coil.

31. The method according to claim 26, wherein the fault current limiter further comprises a secondary end shield positioned adjacent to the upper or lower edge of the superconducting secondary coil, and the secondary end shield is configured to isolate the primary coil.

32. The method according to claim 26, wherein the superconducting primary coil operates with the reactance of the primary coil, most of which is inductive.

33. The method according to claim 26, wherein all partial power design faults are removed within a partial cycle.

34. The method according to claim 26, wherein the superconducting secondary coil generates a high resistance.

35. The method according to claim 26, wherein the at least one superconducting primary coil consists of a plurality of layers, and in mode 2, the layers are magnetically connected to increase the primary mutual inductance.

36. The method according to claim 26, wherein the superconducting primary coil generates a high resistance, which sends all current to the quenched superconducting and non-superconducting coils.

37. An electrical transformer, wherein the electrical transformer comprises a primary magnet coil, a secondary magnet coil adjacent to the primary magnet coil, a superconducting primary magnet coil, a superconducting secondary magnet coil, wherein the primary magnet coil, secondary magnet coil, superconducting primary magnet coil, and superconducting secondary magnet coil are surrounded by a housing such that the inner surface of the primary magnet coil defines an internal volume, and the superconducting secondary magnet coil; a power input interconnected to at least one of the primary magnet coil, secondary magnet coil, superconducting primary magnet coil, and superconducting secondary magnet coil; and a power output interconnected to at least one of the primary magnet coil, secondary magnet coil, superconducting primary magnet coil, and superconducting secondary magnet coil An electrical transformer comprising.

38. The electrical transformer according to claim 37, wherein the superconducting primary and secondary coils are formed from wound high-temperature superconducting tapes, and further comprising a primary coil positioned adjacent to the at least one superconducting primary coil and the at least one superconducting secondary coil.

39. The electrical transformer according to claim 38, wherein the primary magnet coil, secondary magnet coil, and primary coil are made of conventional conductors.

40. The internal volume defines a core interconnected to a cryogen source, the cryogen source being configured to continuously or periodically receive cryogen for maintaining the temperature of at least one of the primary magnet coil, the secondary magnet coil, the superconducting primary magnet coil, the superconducting secondary magnet coil, and the primary coil below a predetermined temperature, the electrical transformer according to claim 37.

41. The plurality of operating modes provided are Mode 1 associated with normal AC functionality, the mode 1 being characterized by a main current to the superconducting primary coil, which induces a secondary current in the superconducting secondary coil, mode 1; and Mode 2, which occurs when the superconducting secondary coil quenches, which shifts the main current to the secondary coil of the conventional conductor so as to be induced by the superconducting primary coil, mode 2; and Mode 3, which occurs when the superconducting primary coil and the superconducting secondary coil are quenched, which shifts the main current to the primary coil, mode 3 The electrical transformer according to claim 38, comprising.

42. The primary magnet coil, secondary magnet coil, superconducting primary magnet coil, and superconducting secondary magnet coil define a solenoid, the solenoid having a solenoid axis corresponding to the magnetic field of the solenoid, the magnetic field of the solenoid generally extending from the upper edge to the lower edge of the at least one superconducting primary coil along the length of the solenoid, the superconducting primary coil being formed from a wound high-temperature superconducting tape having a rectangular cross-section, the tape width being aligned with the solenoid axis, the electrical transformer according to claim 37.

43. The electrical transformer according to claim 42, wherein the tape is installed such that its width is parallel to the maximum magnetic flux generated by the solenoid.

44. The internal volume is a cryogen reservoir, and the electrical transformer according to claim 37 further comprises a cryocooler in thermal communication with the reservoir.

45. The internal volume houses a cryocooler, the electrical transformer according to claim 37.

46. The primary magnetic coil, secondary magnetic coil, superconducting primary magnetic coil, and superconducting secondary magnetic coil are in the shape of an evenly wound toroid, and the toroid is electrically phased into separate axial toroidal winding segments, the electrical transformer according to claim 37.

47. The magnetic flux of the superconducting secondary magnetic coil separates the superconducting primary magnetic coil from the primary magnetic coil and secondary magnetic coil, the electrical transformer according to claim 46.

48. The electrical transformer according to claim 46, further comprising a layer of toroidal conductors with connected layers of poloidal conductors.

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