High-temperature superconducting zero-flux current transformer and assembling method thereof

Abstract

The invention discloses a high-temperature superconducting zero-flux current transformer and an assembly method thereof. The transformer comprises an iron shell, a superconducting compensation coil wound on the outer surface of the iron shell, and a first magnetic flux detection coil-magnetic core system, a second magnetic flux detection coil-magnetic core system and a high-frequency detection coil-magnetic core system which are arranged in the iron shell, wherein each of the first magnetic flux detection coil-magnetic core system, the second magnetic flux detection coil-magnetic core system and the high-frequency detection coil-magnetic core system comprises a magnetic core, a coil framework and a high-temperature superconducting strip; the magnetic core is embedded in the coil framework; according to the zero-flux current transformer, the problem of heating of a magnetic flux detection coil-magnetic core system in the zero-flux current transformer can be solved.

Description

Technical Field

[0001] The present invention relates to the technical field of current measurement, and particularly to a high-temperature superconducting zero-flux current transformer and an assembly method thereof. Background Art

[0002] The zero-flux current transformer adopts magnetic flux detection and closed-loop regulation to make the magnetic flux generated by the compensation current and the measured current in the magnetic core cancel out to zero, so as to achieve accurate current measurement. The core of the sensing element of the zero-flux current transformer is the coil-core system, and the design of this system directly determines the measurement accuracy and measurement range. After being improved by researchers, the existing zero-flux current transformers are used to measure the secondary current of superconducting transformers:

[0003] For example, in the literature "A device for measuring high current at cryogenic temperatures" written by C. Berriaud and A. Donati et al. in 2001 and published in IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY, the researchers added an iron ring that can shield the magnetic field generated by itself between the measured cable and the coil-core system in the sensing element to prevent the problem of local saturation of the magnetic core caused by the deviation of the measured cable from the center position. At the same time, an outer shell made of FeSi is used to shield the external magnetic field to avoid the interference of the external magnetic field on the sensing element and improve the measurement stability. Finally, in order to expand the measurement range of the current transformer, the power amplifier circuit was improved to enable a larger current to be output, and the number of turns of the compensation coil was increased. Finally, under the condition of 4.2K, a current measurement of 38kA with an accuracy better than 100ppm was achieved.

[0004] For example, in the literature "Assembly, and Commissioning of a Cryogenic DC Current Transformer Designed for Measuring Currents of up to 80 kA" written by G. Montenero, P. Arpaia, etc. and published in IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY in 2015, the researchers replaced the common iron ring added between the cable under test and the coil-core system in the sensing element with a pure iron ring, and added a superconducting shielding layer made of MgB2 outside the sensing element, effectively shielding the influence of the external magnetic field on the sensitivity of the element. The sensing element of the newly designed zero-flux current transformer was placed in a cryogenic environment of 4.2 K. In order to ensure the high sensitivity of the detected magnetic field, Ni 81-Mo 5-Fe permalloy with high magnetic permeability and low coercivity at low temperature was used as the magnetic core. In addition, in order to further expand the measurement range of the current transformer, not only was the power amplification circuit adjusted again to increase the compensation current, but also considering the problem that increasing the number of turns of the compensation coil would increase the cryogenic load, a Nb-Ti superconducting wire with low-loss characteristics was selected to wind the compensation coil. Finally, under the condition of 4.2 K, a current measurement of 76 kA was achieved.

[0005] In the research of G. Montenero et al., the researchers used a 1000-turn excitation coil to simulate the cable under test with kA level, and the total current rose at a rate of 26 kA per second. When measuring up to 76 kA, the Nb-Ti superconducting compensation coil quenched, indicating that there were temperature rise and thermal disturbances in the flux detection coil-core system of the zero-flux current transformer. The sensing element of the zero-flux current transformer consists of a magnetic core, a flux detection coil, an iron shell and a superconducting compensation coil. Among them, the detection coil is driven by an alternating current power supply, and inevitably generates AC losses during the measurement process. These losses are dissipated inside the sensing element in the form of heat, which will cause local temperature rise. Seriously, it may cause the superconducting compensation coil outside to quench, thus limiting the measurement range of the current transformer.

[0006] The invention patent application with the patent publication number CN105304262A discloses a high-temperature superconducting coil device for an alternating magnetic field. In this patent, the high-temperature superconducting tape gradually widens from the center to both ends of the single-pancake winding, and the corresponding current-carrying capacity of the high-temperature superconducting tape also gradually increases, which can effectively compensate for the gradually increasing magnetic field. Therefore, when the current passes through the single-pancake winding with a series structure, the current-carrying safety margin of the high-temperature superconducting tape approaches equality, thereby enabling the high-temperature superconducting single-pancake winding to remain superconducting under a relatively high vertical magnetic field, effectively improving the current-carrying capacity and stability of the high-temperature superconducting coil device under a strong magnetic field. The coil made in this patent is a pancake coil, and most of the existing high-temperature superconducting coils are also pancake coils and racetrack coils. The research on AC loss also mainly focuses on these two types of coils. During the process of bending the superconducting tape, damage and plastic deformation may occur, which will affect the critical current performance of the tape. Summary of the Invention

[0007] The technical problems to be solved by the present invention are as follows: the AC loss problem of the flux detection coil-core system in a zero-flux current transformer, and the performance degradation problem of the high-temperature superconducting tape caused by strain during the bending process.

[0008] To solve the above technical problems, the present invention provides the following technical solutions:

[0009] A high-temperature superconducting zero-flux current transformer includes an iron shell 100, a superconducting compensation coil 200 wound around the outer surface of the iron shell 100, and a first flux detection coil-core system 310, a second flux detection coil-core system 320, and a high-frequency detection coil-core system 330 placed inside the iron shell 100;

[0010] Among them, the first flux detection coil-core system 310, the second flux detection coil-core system 320, and the high-frequency detection coil-core system 330 all include a core 31, a high-temperature superconducting tape 34, and a coil skeleton 35;

[0011] The core 31 is embedded in the coil skeleton 35; the high-temperature superconducting tape 34 is wound around the coil skeleton 35, and the upper and lower surface of the longitudinal section of the coil skeleton 35 is a curved surface 352, and the radius of the curved surface 352 is greater than the minimum bending radius of the high-temperature superconducting tape 34.

[0012] In an embodiment of the present invention, the cross-section of the core 31 is a ring.

[0013] In an embodiment of the present invention, the insulating coil skeleton 35 is circular; the coil skeleton 35 includes an upper coil skeleton 32 and a lower coil skeleton 33, and a core groove 36 is provided in both the upper coil skeleton 32 and the lower coil skeleton 33.

[0014] In an embodiment of the present invention, the upper coil bobbin 32 is provided with an upper copper sheet slot 321, and an upper copper sheet 322 is fixed in the upper copper sheet slot 321; after the upper copper sheet 322 is fixed in the upper copper sheet slot 321, the outer surface is flush with the outer surface of the upper coil bobbin 32 at the corresponding position; the lower coil bobbin 33 is provided with a lower copper sheet slot 331, and a lower copper sheet 332 is fixed in the lower copper sheet slot 331; after the lower copper sheet 332 is fixed in the lower copper sheet slot 331, the outer surface is flush with the outer surface of the lower coil bobbin 33 at the corresponding position.

[0015] In an embodiment of the present invention, the coil bobbin 35 is provided with a superconducting tape slot 351, and the high-temperature superconducting tape 34 is located in the superconducting tape slot 351.

[0016] In an embodiment of the present invention, the starting end of the high-temperature superconducting tape 34 is welded to the surface of the upper copper sheet 322 or the lower copper sheet 332. After winding is completed, the end of the high-temperature superconducting tape 34 is welded to the surface of the other copper sheet; and signal lines 37 are respectively welded on the surfaces of the upper copper sheet 322 and the lower copper sheet 332.

[0017] In an embodiment of the present invention, the iron shell 100 includes an upper half shell 110 and a lower half shell 120 assembled by a snap-fit method; and the upper half shell 110 is further provided with a signal line hole 111; the signal lines 37 on the first magnetic flux detection coil-core system 310, the second magnetic flux detection coil-core system 320, and the high-frequency detection coil-core system 330 pass through the signal line hole 111 and are connected to an external electronic detection circuit.

[0018] In an embodiment of the present invention, the external electronic detection circuit includes an oscillation circuit module 11, a signal detection circuit module 12, a power amplifier 13, a low-frequency signal processing module 16, and a high-frequency signal processing module 17;

[0019] The same-named ends of the coils of the first magnetic flux detection coil-core system 310 and the different-named ends of the coils of the second magnetic flux detection coil-core system 320 are connected to the same oscillation circuit module 11 to form a pair of equal and opposite magnetic fluxes on the two coils; and the different-named ends of the coils of the first magnetic flux detection coil-core system 310 and the same-named ends of the coils of the second magnetic flux detection coil-core system 320 are connected to the signal detection circuit module 12; the output end of the signal detection circuit module 12 is connected to the input end of the low-frequency signal processing module 16; the coil of the high-frequency detection coil-core system 330 is connected to the input end of the high-frequency signal processing module 17; the input end of the power amplifier 13 is connected to the output ends of the high-frequency signal processing module 17 and the low-frequency signal processing module 16;

[0020] The output end of the power amplifier 13 is connected to the superconducting compensation coil 200;

[0021] During the current measurement process, the low-frequency current in the measured current is coupled to the first magnetic flux detection coil-core system 310 and the second magnetic flux detection coil-core system 320. After passing through the signal detection circuit module 12 and the low-frequency signal processing module 16, the driving power amplifier 13 generates ampere-turns equal in magnitude and opposite in direction to the measured current on the superconducting compensation coil 200, achieving zero magnetic flux cancellation.

[0022] When the measured current is a high-frequency current, the induced voltage formed by the measured current on the high-frequency detection coil-core system 330 is processed and amplified by the high-frequency signal processing module 17, and then the driving power amplifier 13 generates ampere-turns equal in magnitude and opposite in direction to the measured current on the superconducting compensation coil 200 to achieve magnetic flux cancellation.

[0023] In an embodiment of the present invention, the external electronic detection circuit includes a sampling resistor 14 and a digital voltmeter 15; the sampling resistor 14 is connected to the superconducting compensation coil 200, and the digital voltmeter 15 is connected in parallel with the sampling resistor 14.

[0024] The present invention also provides an assembly method for a high-temperature superconducting zero-flux current transformer, including:

[0025] First, assemble the first magnetic flux detection coil-core system 310, the second magnetic flux detection coil-core system 320, and the high-frequency detection coil-core system 330 in sequence, all including:

[0026] The magnetic core 31 is fixed inside the coil skeleton 35; the high-temperature superconducting tape 34 is wound around the coil skeleton 35. After the winding is completed, the high-temperature superconducting tape 34 is connected to the signal line 37.

[0027] After completing the first magnetic flux detection coil-core system 310, the second magnetic flux detection coil-core system 320, and the high-frequency detection coil-core system 330, place them into the iron shell 100 in sequence, and the signal lines 37 connected to the first magnetic flux detection coil-core system 310, the second magnetic flux detection coil-core system 320, and the high-frequency detection coil-core system 330 pass through the iron shell 100.

[0028] Then wind the superconducting compensation coil 200 on the outer surface of the iron shell 100.

[0029] Finally, connect the start end and end end of the superconducting compensation coil 200 and the signal lines 37 connected to the first magnetic flux detection coil-core system 310, the second magnetic flux detection coil-core system 320, and the high-frequency detection coil-core system 330 to the external electronic detection circuit.

[0030] Compared with the prior art, the beneficial effects of the present invention are:

[0031] In the present invention, both the first and second flux detection coil-core systems and the high-frequency detection coil-core system adopt high-temperature superconducting materials. Compared with conventional copper wires, superconducting materials generally generate less AC loss under the same conditions, so the heat output during the detection process can be controlled, and thus the occurrence of quench in the outermost superconducting compensation coil can be effectively avoided. Since the occurrence of quench directly limits the measurement range of the entire current transformer, the design of the present invention can theoretically expand the measurement range of the zero-flux current transformer and is expected to break through the measurement limit of 76 kA.

[0032] High-temperature superconducting tapes cannot be bent arbitrarily. During the process of bending high-temperature superconducting tapes, damage and plastic deformation may occur, which will affect the critical current performance of high-temperature superconducting tapes. Therefore, a coil skeleton needs to be designed to support high-temperature superconducting tapes. To avoid damage, the curved surface of the coil skeleton design must ensure that the radius is greater than the minimum bending radius of the high-temperature superconducting tape.

[0033] The design of the coil skeleton brings convenience to embedding the core and uniformly winding the high-temperature superconducting coil. On the one hand, slots are opened in the coil skeleton according to the size of the core to achieve the best fit as much as possible. On the other hand, slots are opened on the surface of the coil skeleton according to the size and winding trajectory of the high-temperature superconducting tape, which can effectively ensure the number of coil turns and uniformity.

[0034] To place the core, the coil skeleton is designed to be split (each half is one-half). Slots are opened on the surface of the skeleton according to the winding trajectory, and the manufacturing process is complex, with relatively high requirements for the hardness of the coil skeleton.

[0035] The present invention provides an induction element of a high-temperature superconducting zero-flux current transformer with low-loss characteristics to reduce losses and increase the measurement range of the entire device. Brief Description of the Drawings

[0036] Figure 1 Schematic diagram of a high-temperature superconducting zero-flux current transformer according to an embodiment of the present invention.

[0037] Figure 2 Schematic diagram of the iron shell according to an embodiment of the present invention.

[0038] Figure 3 Schematic diagram of the upper half shell according to an embodiment of the present invention.

[0039] Figure 4 Schematic diagram of the core and coil skeleton according to an embodiment of the present invention.

[0040] Figure 5 Schematic diagram of the core according to an embodiment of the present invention.

[0041] Figure 6 Schematic diagram of the superconducting tape slot according to an embodiment of the present invention.

[0042] Figure 7 Schematic diagram of the upper coil skeleton and the lower coil skeleton according to an embodiment of the present invention.

[0043] Figure 8 Partial cross-sectional view of the induction element according to an embodiment of the present invention.

[0044] Figure 9 Schematic diagram of the connection between the induction element and the external electronic detection circuit according to an embodiment of the present invention.

[0045] Figure 10 Schematic diagram of the zero-flux realization principle of the high-temperature superconducting zero-flux current transformer according to an embodiment of the present invention. Detailed implementation manners

[0046] To facilitate the understanding of the technical solution of the present invention by those skilled in the art, the technical solution of the present invention will be further described below in conjunction with the accompanying drawings of the specification.

[0047] The terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present application, "a plurality" means two or more unless otherwise specifically defined.

[0048] Please refer to Figure 1 As shown in the figure, the present invention provides a high-temperature superconducting zero-flux current transformer, which includes an iron shell 100, a superconducting compensation coil 200 wound around the outer surface of the iron shell 100, and a first flux detection coil-core system 310, a second flux detection coil-core system 320, and a high-frequency detection coil-core system 330 placed inside the iron shell 100. Among them, the iron shell 100, the superconducting compensation coil 200, the first flux detection coil-core system 310, the second flux detection coil-core system 320, and the high-frequency detection coil-core system 330 are the induction elements of the high-temperature superconducting zero-flux current transformer.

[0049] Please refer to Figures 1 to 3 As shown in the figure, in an embodiment of the present invention, the iron shell 100 includes an upper half shell 110 and a lower half shell 120 assembled in a snap-fit manner, and a signal line hole 111 is further provided on the upper half shell 110. The iron shell 100 is circular. The superconducting compensation coil 200 is uniformly wound around the outer surface of the iron shell 100.

[0050] Please refer to Figure 1 and Figures 4 to 8As shown, in an embodiment of the present invention, the first magnetic flux detection coil - magnetic core system 310, the second magnetic flux detection coil - magnetic core system 320, and the high - frequency detection coil - magnetic core system 330 all include a magnetic core 31, an upper coil bobbin 32, a lower coil bobbin 33, and a high - temperature superconducting tape 34.

[0051] In this embodiment, the upper coil bobbin 32 and the lower coil bobbin 33 are arranged in a snap - fit manner, and after snap - fitting, a complete coil bobbin 35 is formed. The magnetic core 31 is embedded in the coil bobbin 35. There is a superconducting tape groove 351 on the coil bobbin 35, and the high - temperature superconducting tape 34 is wound around the coil bobbin 35 by being located within the superconducting tape groove 351.

[0052] In this embodiment, the longitudinal section of the magnetic core 31 is rectangular, and the cross - section is circular. The insulating coil bobbin 35 is circular - ring - shaped, and there are magnetic core grooves 36 in both the upper coil bobbin 32 and the lower coil bobbin 33. According to the size of the magnetic core 31, the inside can be designed to fit the coil bobbin 35. The inner groove of the coil bobbin 35 can completely embed the magnetic core 31. The cross - sections and structures of the upper coil bobbin 32 and the lower coil bobbin 33 are as Figure 4 shown. After the magnetic core 31 is placed in the coil bobbin 35, it is fixed with glue.

[0053] In this embodiment, the upper and lower surface of the longitudinal section of the coil bobbin 35 are curved surfaces 352, and the radius of the curved surface 352 is greater than the minimum bending radius of the high - temperature superconducting tape 34. The high - temperature superconducting tape 34 is wound around the insulating coil bobbin 35 to form a superconducting coil. The superconducting coil of the present invention is a toroidal coil, as shown in Figure 6 shown.

[0054] The high - temperature superconducting tape 34 cannot be bent arbitrarily. During the process of bending the high - temperature superconducting tape 34, damage and plastic deformation may occur, affecting the critical current performance of the high - temperature superconducting tape 34. Therefore, it is necessary to design the coil bobbin 35 to support the high - temperature superconducting tape 34. To avoid damage, the radius of the curved surface 352 designed for the coil bobbin 35 must be greater than the minimum bending radius of the high - temperature superconducting tape 34. It should be noted that the minimum bending radius refers to the radius when the critical current of the high - temperature superconducting tape 34 is reduced to 95% of the initial value in the bent state.

[0055] In an embodiment of the present invention, the upper coil bobbin 32 is provided with an upper copper - sheet slot 321, and an upper copper sheet 322 is fixed in the upper copper - sheet slot 321. After the upper copper sheet 322 is fixed in the upper copper - sheet slot 321, its outer surface is flush with the outer surface of the upper coil bobbin 32 at the corresponding position. The lower coil bobbin 33 is provided with a lower copper - sheet slot 331, and a lower copper sheet 332 is fixed in the lower copper - sheet slot 331. After the lower copper sheet 332 is fixed in the lower copper - sheet slot 331, its outer surface is flush with the outer surface of the lower coil bobbin 33 at the corresponding position.

[0056] In this embodiment, the starting end of the high-temperature superconducting tape 34 is welded to the surface of the upper copper sheet 322 or the lower copper sheet 332. After the winding is completed, the end of the high-temperature superconducting tape 34 is welded to the surface of the other copper sheet. For example, when the starting end of the high-temperature superconducting tape 34 is welded to the surface of the upper copper sheet 322, after the winding is completed, the end of the high-temperature superconducting tape 34 is welded to the surface of the lower copper sheet 332. Signal lines 37 are also welded to the surfaces of the upper copper sheet 322 and the lower copper sheet 332 respectively. The signal lines 37 on the first magnetic flux detection coil-core system 310, the second magnetic flux detection coil-core system 320, and the high-frequency detection coil-core system 330 pass through the signal line holes 111 and are connected to an external electronic detection circuit.

[0057] In this embodiment, the upper copper sheet 322 and the lower copper sheet 332 are respectively fixed in the upper copper sheet slot 321 and the lower copper sheet slot 331 using glue. To enable the high-temperature superconducting tape 34 to be evenly distributed on the surface of the coil skeleton 35, as Figure 6 shown, superconducting tape slots 351 are provided on the surface of the coil skeleton 35 according to the width and thickness of the high-temperature superconducting tape 34 to ensure that the performance of the high-temperature superconducting tape 34 does not degrade during the winding process.

[0058] In this embodiment, according to the above connection method, the assembly of the first magnetic flux detection coil-core system 310, the second magnetic flux detection coil-core system 320, and the high-frequency detection coil-core system 330 is completed in sequence, and they are respectively wrapped and fixed evenly with tape. In the Figure 8 way, the three fixed coil-core systems are sequentially placed into the lower half shell 120. After being placed neatly, the upper half shell 110 is buckled. The superconducting compensation coil 200 is evenly wound outside the iron shell 100 and is finally wrapped and fixed with tape. The starting end and the ending end of the superconducting compensation coil 200 are connected to an external electronic detection circuit.

[0059] Please refer to Figures 1 to 8 shown. In an embodiment of the present invention, when in use, the cable A to be measured is passed through the sensing element in the Figure 1 way. As Figure 9 shown, the sensing element needs to be completely immersed in a low-temperature environment, and the electronic output end of the high-temperature superconducting zero-flux current transformer should be connected to the digital voltmeter 15. After the measured current flows through the sensing element, a voltage Uout is output by the external electronic detection circuit. According to the principle Figure 10 it can be known that the current Is in the superconducting compensation coil 200 is obtained by dividing this voltage by the resistance value of the sampling resistor 14, and then multiplying by the number of turns Ns of the superconducting compensation coil 200, the measured current can be obtained. Among them, Figure 9Among them, the reference numeral Ws represents the winding of the superconducting compensation coil 200, Wdc1 represents the winding of the coil in the second magnetic flux detection coil - magnetic core system 320, Wdc2 represents the winding of the coil in the first magnetic flux detection coil - magnetic core system 310, Wac represents the winding of the coil in the high - frequency detection coil - magnetic core system 330, DCCT represents the direct - current current transformer, and Ip represents the current of the cable under test.

[0060] Please refer to Figures 1 to 10 As shown, in an embodiment of the present invention, the external electronic detection circuit includes an oscillation circuit module 11, a signal detection circuit module 12, a power amplifier 13, a sampling resistor 14, a digital voltmeter 15, a low - frequency signal processing module 16, and a high - frequency signal processing module 17.

[0061] In this embodiment, the same - named ends of the coils of the first magnetic flux detection coil - magnetic core system 310 and the opposite - named ends of the coils of the second magnetic flux detection coil - magnetic core system 320 are connected to the same oscillation circuit module 11, forming a pair of equal - amount and opposite - direction magnetic fluxes on the two coils. And the opposite - named ends of the coils of the first magnetic flux detection coil - magnetic core system 310 and the same - named ends of the coils of the second magnetic flux detection coil - magnetic core system 320 are sequentially connected to the signal detection circuit module 12 and the low - frequency signal processing module 16. The superconducting compensation coil 200 is connected to the output of the power amplifier 13, and the input of the power amplifier 13 is connected to the low - frequency signal processing module 16 and the high - frequency signal processing module 17.

[0062] The first magnetic flux detection coil - magnetic core system 310 and the second magnetic flux detection coil - magnetic core system 320 are responsible for detecting and canceling the magnetic - flux change of the cable under test. Specifically, during the current measurement process, the low - frequency current in the current under test is coupled to the first magnetic flux detection coil - magnetic core system 310 and the second magnetic flux detection coil - magnetic core system 320. After being processed by the signal detection circuit module 12 and the low - frequency signal processing module 16, it drives the power amplifier 13 to generate ampere - turns equal to and opposite to the current under test on the superconducting compensation coil 200, achieving zero magnetic - flux cancellation.

[0063] The high - frequency detection coil - magnetic core system 330 is used to compensate the ampere - turns of the high - frequency current in the current under test. When the current under test is a high - frequency current, that is, when the frequency of the current under test is relatively high, due to bandwidth limitations, the signals obtained by the first magnetic flux detection coil - magnetic core system 310 and the second magnetic flux detection coil - magnetic core system 320 are relatively small. However, the induced voltage formed by the current under test on the high - frequency detection coil - magnetic core system 330, after being processed and amplified by the high - frequency signal processing module 17, can drive the power amplifier 13 to generate ampere - turns equal to and opposite to the current under test on the superconducting compensation coil 200, achieving magnetic - flux cancellation.

[0064] In this embodiment, the sampling resistor 14 is connected to the superconducting compensation coil 200, and the digital voltmeter 15 is connected in parallel with the sampling resistor 14. After the measured current flows through the sensing element, a voltage is output by the sampling resistor 14, and this voltage is measured by the digital voltmeter 15.

[0065] In this embodiment, the present invention does not limit the specific circuit form of the oscillation circuit module 11, the signal detection circuit module 12, the low-frequency signal processing module 16, and the high-frequency signal processing module 17. Among them, the function of the oscillation circuit module 11 is to make the magnetic core 31 alternately enter the magnetic saturation state under the action of an alternating current signal. The power amplifier 13, the sampling resistor 14, and the digital voltmeter 15 are all products that can be purchased on the market.

[0066] Please refer to Figures 1 to 10 As shown, the present invention also provides an assembly method for a high-temperature superconducting zero-flux current transformer, including:

[0067] S10. First, assemble the first magnetic flux detection coil-core system 310, the second magnetic flux detection coil-core system 320, and the high-frequency detection coil-core system 330 in sequence, all of which include:

[0068] After the magnetic core 31 is placed inside the upper coil skeleton 32, it is fixed with glue. Glue is squeezed into the lower coil skeleton 33 and buckled with the upper coil skeleton 32, and the magnetic core 31 is fixed inside the coil skeleton 35; the high-temperature superconducting tape 34 is wound around the coil skeleton 35, and after the winding is completed, the high-temperature superconducting tape 34 is connected to the signal line 37.

[0069] S20. After completing the first magnetic flux detection coil-core system 310, the second magnetic flux detection coil-core system 320, and the high-frequency detection coil-core system 330, then place them into the iron shell 100 in sequence, and the signal lines 37 connected to the first magnetic flux detection coil-core system 310, the second magnetic flux detection coil-core system 320, and the high-frequency detection coil-core system 330 pass through the iron shell 100.

[0070] S30. Then wind the superconducting compensation coil 200 on the outer surface of the iron shell 100.

[0071] S40. Finally, connect the start end and the end of the superconducting compensation coil 200 and the signal lines 37 connected to the first magnetic flux detection coil-core system 310, the second magnetic flux detection coil-core system 320, and the high-frequency detection coil-core system 330 to an external electronic detection circuit.

[0072] It is obvious to those skilled in the art that the present invention is not limited to the details of the above-described exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-restrictive. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be embraced within the present invention, and any reference signs in the claims should not be construed as limiting the claims involved.

[0073] The above-described embodiments merely represent the implementation manners of the invention. The protection scope of the present invention is not limited to the above embodiments. For those skilled in the art, without departing from the concept of the present invention, several deformations and improvements can be made, and these all belong to the protection scope of the present invention.

Claims

1. A high-temperature superconducting zero-flux current transformer, characterized in that It includes an iron shell (100), a superconducting compensation coil (200) wound around the outer surface of the iron shell (100), and a first magnetic flux detection coil - magnetic core system (310), a second magnetic flux detection coil - magnetic core system (320), and a high - frequency detection coil - magnetic core system (330) placed inside the iron shell (100); Among them, the first magnetic flux detection coil - magnetic core system (310), the second magnetic flux detection coil - magnetic core system (320), and the high - frequency detection coil - magnetic core system (330) all include a magnetic core (31), a high - temperature superconducting tape (34), and a coil skeleton (35); The magnetic core (31) is embedded in the coil skeleton (35); the high - temperature superconducting tape (34) is wound around the coil skeleton (35), and the upper and lower surface of the longitudinal section of the coil skeleton (35) are curved surfaces (352), and the radius of the curved surface (352) is greater than the minimum bending radius of the high - temperature superconducting tape (34).

2. The high-temperature superconducting zero-flux current transformer according to claim 1, wherein The cross - section of the magnetic core (31) is a circular ring.

3. The high-temperature superconducting zero-flux current transformer according to claim 1, characterized in that The insulating coil skeleton (35) is circular - ring - shaped; the coil skeleton (35) includes an upper coil skeleton (32) and a lower coil skeleton (33), and magnetic core grooves (36) are arranged in both the upper coil skeleton (32) and the lower coil skeleton (33).

4. The high-temperature superconducting zero-flux current transformer according to claim 3, characterized in that, The upper coil skeleton (32) is provided with an upper copper - sheet slot (321), and an upper copper sheet (322) is fixed in the upper copper - sheet slot (321); after the upper copper sheet (322) is fixed in the upper copper - sheet slot (321), its outer surface is flush with the outer surface of the upper coil skeleton (32) at the corresponding position; the lower coil skeleton (33) is provided with a lower copper - sheet slot (331), and a lower copper sheet (332) is fixed in the lower copper - sheet slot (331); after the lower copper sheet (332) is fixed in the lower copper - sheet slot (331), its outer surface is flush with the outer surface of the lower coil skeleton (33) at the corresponding position.

5. The high-temperature superconducting zero-flux current transformer according to claim 1, wherein The coil skeleton (35) is provided with a superconducting - tape slot (351), and the high - temperature superconducting tape (34) is located in the superconducting - tape slot (351).

6. The high-temperature superconducting zero-flux current transformer according to claim 4, wherein, The starting end of the high - temperature superconducting tape (34) is welded to the surface of the upper copper sheet (322) or the lower copper sheet (332), and after the winding is completed, the end of the high - temperature superconducting tape (34) is welded to the surface of the other copper sheet; and signal lines (37) are respectively welded on the surfaces of the upper copper sheet (322) and the lower copper sheet (332).

7. The high-temperature superconducting zero-flux current transformer according to claim 1, wherein The iron shell (100) includes an upper half - shell (110) and a lower half - shell (120) assembled by a snap - fit method; and a signal - line hole (111) is also provided on the upper half - shell (110); the signal lines (37) on the first magnetic flux detection coil - magnetic core system (310), the second magnetic flux detection coil - magnetic core system (320), and the high - frequency detection coil - magnetic core system (330) pass through the signal - line hole (111) and are connected to an external electronic detection circuit.

8. The high-temperature superconducting zero-flux current transformer according to claim 7, characterized in that, The external electronic detection circuit includes an oscillation - circuit module (11), a signal - detection - circuit module (12), a power amplifier (13), a low - frequency signal - processing module (16), and a high - frequency signal - processing module (17); The like-named ends of the coils of the first magnetic flux detection coil-core system (310) and the unlike-named ends of the coils of the second magnetic flux detection coil-core system (320) are connected to the same oscillation circuit module (11), forming a pair of equal and opposite magnetic fluxes on the two coils; and the unlike-named ends of the coils of the first magnetic flux detection coil-core system (310) and the like-named ends of the coils of the second magnetic flux detection coil-core system (320) are connected to the signal detection circuit module (12); the output end of the signal detection circuit module (12) is connected to the input end of the low-frequency signal processing module (16); the coil of the high-frequency detection coil-core system (330) is connected to the input end of the high-frequency signal processing module (17); the input end of the power amplifier (13) is connected to the output ends of the high-frequency signal processing module (17) and the low-frequency signal processing module (16); The output end of the power amplifier (13) is connected to the superconducting compensation coil (200); During the current measurement, the low-frequency current in the measured current is coupled to the first magnetic flux detection coil-core system (310) and the second magnetic flux detection coil-core system (320), and after passing through the signal detection circuit module (12) and the low-frequency signal processing module (16), it drives the power amplifier (13) to generate ampere-turns equal and opposite to the measured current on the superconducting compensation coil (200), achieving zero magnetic flux cancellation; When the measured current is a high-frequency current, the induced voltage formed by the measured current on the high-frequency detection coil-core system (330) is processed and amplified by the high-frequency signal processing module (17), and then drives the power amplifier (13) to generate ampere-turns equal and opposite to the measured current on the superconducting compensation coil (200), achieving magnetic flux cancellation.

9. The high-temperature superconducting zero-flux current transformer according to claim 7, characterized in that, The external electronic detection circuit includes a sampling resistor (14) and a digital voltmeter (15); the sampling resistor (14) is connected to the superconducting compensation coil (200), and the digital voltmeter (15) is connected in parallel with the sampling resistor (14).

10. An assembly method of the high-temperature superconducting zero-flux current transformer according to any one of claims 1-9, characterized in that, Including: First, assemble the first magnetic flux detection coil-core system (310), the second magnetic flux detection coil-core system (320) and the high-frequency detection coil-core system (330) in sequence, all of which include: The magnetic core (31) is placed and fixed inside the coil bobbin (35); the high-temperature superconducting tape (34) is wound around the coil bobbin (35), and after the winding is completed, the high-temperature superconducting tape (34) is connected to the signal wire (37); After completing the first magnetic flux detection coil-core system (310), the second magnetic flux detection coil-core system (320) and the high-frequency detection coil-core system (330), then place them into the iron shell (100) in sequence, and the signal wires (37) connected to the first magnetic flux detection coil-core system (310), the second magnetic flux detection coil-core system (320) and the high-frequency detection coil-core system (330) pass through the iron shell (100); Then wind the superconducting compensation coil (200) on the outer surface of the iron shell (100); Finally, the start end and end of the superconducting compensation coil (200), as well as the signal lines (37) connected to the first magnetic flux detection coil - magnetic core system (310), the second magnetic flux detection coil - magnetic core system (320), and the high - frequency detection coil - magnetic core system (330), are connected to an external electronic detection circuit.

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