High-temperature superconducting quenching detection sensor, system and method based on superconducting and optical fibers

Abstract

The invention relates to the technical field of high-temperature superconducting quench detection, and discloses a high-temperature superconducting quench detection sensor, system and method based on superconducting and optical fibers, and the sensor comprises a superconducting material layer which is used for being arranged in parallel or side by side with a to-be-detected superconducting transmission cable so as to sense the temperature and superconducting state of the to-be-detected superconducting transmission cable; the optical fiber and the superconducting material layer are coaxially arranged, or the length direction of the optical fiber is parallel to the length direction of the superconducting material layer, and the optical fiber is used for collecting the temperature of the superconducting material layer; and the insulating layer wraps the superconducting material layer and is used for preventing the current of the superconducting material layer from being shunted. Qualitative and positioning detection is carried out on quench through the coupling effect of photoelectricity and heat, and the detection reliability is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of high-temperature superconducting detection technology, and in particular to a high-temperature superconducting quench detection sensor, system and method based on superconducting and optical fiber. Background Art

[0002] High-temperature superconductors generally refer to materials with a critical temperature above 40K, typically capable of achieving superconductivity at liquid nitrogen temperatures. A superconducting quench can easily burn out the superconducting material, altering its physical properties and permanently losing its superconducting properties. Due to the extreme cost of current high-temperature superconducting materials, burnout after a quench is unacceptable. Quench diagnosis is essential to prevent quench damage. By preventing the quench process from progressing, the high-temperature superconducting material maintains its original superconducting properties.

[0003] High-temperature superconducting quench detection or diagnosis mainly faces the following difficulties: (1) Detection speed lag: After a quench, the normal area propagates slowly. The mainstream voltage detection method will bring a certain lag time to the system. At the same time, there will be multiple hot spots. Therefore, it is necessary to develop a fast quench detection technology.

[0004] (2) Difficulty in signal detection: The voltage signal after quenching is relatively weak, and the quenching region only produces a low level of resistance voltage. Furthermore, the voltage signal is easily affected by the surrounding electromagnetic environment, resulting in high noise levels and difficulty in distinguishing. Various methods based on heat, sound, electricity, and magnetism have been developed, but each has its own limitations and problems.

[0005] (3) Low reliability of quench detection: Many physical, electrical, mechanical, and acoustic phenomena generated during the quench process are mixed with the physical, electrical, mechanical, and acoustic phenomena of the cable and magnet themselves, making them difficult to distinguish. At the same time, false positive quench phenomena also have a negative impact on the reliability of quench diagnosis.

[0006] For the application of quench diagnostic technology, each of the above points is very important and indispensable. If the advantages of these aspects can be combined, it will effectively promote the application of high-temperature superconductors. None of the current technologies can solve these problems at the same time. Summary of the Invention

[0007] In order to solve the above problems, the present invention provides a high-temperature superconducting quench detection sensor, system and method based on superconductivity and optical fiber, which closely combines optical fiber materials and superconducting materials and utilizes thermal, optical and electrical coupling to promote each other.

[0008] The present invention is achieved through the following technical solutions: A high-temperature superconducting quench detection sensor based on superconducting and optical fiber, comprising: a superconducting material layer, arranged in parallel or side by side with the superconducting transmission cable to be tested, so as to sense the temperature and superconducting state of the superconducting transmission cable to be tested; an optical fiber, coaxially arranged with the superconducting material layer, or with the length direction of the optical fiber parallel to the length direction of the superconducting material layer, for collecting the temperature of the superconducting material layer and the specific position of each temperature point; The insulating layer wraps the superconducting material layer to prevent the current in the superconducting material layer from being shunted.

[0009] As an optimization, the superconducting material layer, the optical fiber and the insulating layer are coaxially arranged, and from the inside to the outside they are the optical fiber, the superconducting material layer and the insulating layer.

[0010] As an optimization, the superconducting material layer is a wire, and the superconducting material layer and the optical fiber are arranged side by side in the insulating layer so as to be wrapped by the insulating layer.

[0011] As an optimization, the superconducting material layer is a wire, the superconducting material layer is wrapped by the insulating layer, and the optical fiber is in contact with the insulating layer.

[0012] As an optimization, the superconducting material layer is a tape, and the superconducting material layer and the optical fiber are arranged in parallel in the insulating layer.

[0013] As an optimization, the superconducting material layer is a tape, and the superconducting material layer is arranged in the insulating layer, the optical fiber is arranged in parallel with the superconducting material layer, and the optical fiber is fixed to the outer surface of the insulating layer.

[0014] The present invention also discloses a high-temperature superconducting quench detection system, which is used to detect the temperature and voltage on a superconducting transmission cable to be tested to determine whether the superconducting material of the superconducting transmission cable to be tested is quenched. The system comprises the aforementioned high-temperature superconducting quench detection sensor based on superconducting and optical fiber, a voltmeter, a detection current source, a transmission current source, and a distributed optical fiber thermometer. The high-temperature superconducting quench detection sensor is closely attached to the superconducting transmission cable to be tested in parallel. Two ends of the high-temperature superconducting quench detection sensor are respectively connected to two ends of the detection current source to form a detection loop; The two ends of the superconducting transmission cable to be tested are respectively connected to the two ends of the transmission current source to form a working loop. The two ends of the voltmeter are respectively connected to the negative ends of the detection current source and the transmission current source, so as to respectively detect the voltage difference obtained after passing through the high-temperature superconducting quench detection sensor and the superconducting transmission cable to be tested in the detection loop and the working loop; The distributed optical fiber thermometer is connected to one end of the high-temperature superconducting quench detection sensor to detect the temperature of the high-temperature superconducting quench detection sensor.

[0015] As an optimization, the operating temperature (or service temperature) To of the superconducting transmission cable to be tested is not greater than the quench shunting critical temperature Tcs of the superconducting material layer, so as to ensure that the high-temperature superconducting quench detection sensor is in a superconducting state under normal working conditions.

[0016] As an optimization, the two ends of the detection current source are respectively connected to the superconducting material layer of the high-temperature superconducting quench detection sensor, the two ends of the transmission current source are respectively connected to the superconducting material layer of the superconducting transmission cable to be tested, and the distributed optical fiber thermometer is connected to the optical fiber of the high-temperature superconducting quench detection sensor.

[0017] The present invention also discloses a high-temperature superconducting quench detection method, which uses the above-mentioned high-temperature superconducting quench detection system to detect a superconducting transmission cable, comprising: Measure the voltage difference between the working circuit and the detection circuit using a voltmeter; Detecting the temperature along the high-temperature superconducting quench detection sensor and the specific position of each temperature point by a distributed optical fiber thermometer; When the voltage difference between the working circuit and the detection circuit measured by the voltmeter increases and exceeds a critical value, it indicates that the superconducting transmission cable to be tested has quenched. If the temperature of the high-temperature superconducting quench detection sensor detected by the distributed optical fiber thermometer exceeds a set temperature threshold, it also indicates that the superconducting transmission cable to be tested has quenched. The position and width of the quench of the superconducting transmission cable to be tested are determined according to the temperature signal changes at different positions before and after the quench of the distributed optical fiber thermometer.

[0018] Compared with the prior art, the present invention has the following advantages and beneficial effects: 1. Fast Detection: The detection method of the present invention is based on the combination of fiber optic detection and superconducting material voltage detection. Because fiber optic detection has a rapid temperature response and high light propagation speed, the total detection time depends on the processing speed. Using fiber optic detection alone, the time from quench to quench confirmation is 180ms, which is already very fast compared to other detection methods. However, combined with the insulated superconducting material voltage detection of the present invention, the signal detection time, which used to take 500ms, is reduced to 6ms. This combined approach reduces the overall quench detection time to around 90ms, allowing sufficient time for protective action.

[0019] 2. Strong detection signal: The present invention utilizes a superconducting material sensor with an insulating layer. When a quench occurs in the superconducting transmission line being tested, the quench detection sensor of the present invention also quenches. However, the insulating layer prevents current shunting. The resistance at the quench site increases suddenly, and the voltage measured across both ends also increases suddenly. For example, if a low-temperature superconducting material is used as the sensor, a signal strength of 0.1V can be achieved. If a high-temperature superconducting material is used as the sensor, the signal strength can reach 1V or above. When the superconducting detection sensor quenches, the sensor itself becomes a small heat source, directly and locally heating the optical fiber. This makes the temperature signal detected by the optical fiber faster and stronger, and facilitates subsequent quench detection.

[0020] 3. Quench judgment is more reliable: Due to the enhancement of the detection signal and the acceleration of the response speed, the quench judgment is promoted. However, one detection method is often not reliable enough. The present invention combines the voltage detection of the superconducting detection sensor and the temperature detection of the optical fiber sensor. The coupling of photoelectricity and heat can verify each other and promote the quench judgment. For example, under normal circumstances, the optical fiber temperature and the superconducting sensor voltage will rise synchronously, and a reliable conclusion of the quench can be drawn. In special circumstances, the rise of the optical fiber temperature detection data may be caused by local electromagnetic stress, and the quench cannot be judged. If the voltage value at this time also changes suddenly, it is confirmed to be a quench. Therefore, quench detection can also be achieved under extreme conditions, reducing the risk of failure. The detection system adopts a parallel arrangement of the transmission cable and the superconducting sensor, and the voltage measurement is connected at the end, which can eliminate the induced voltage along the way and reduce the interference of noise signals. At the same time, the optical fiber signal is insensitive to electromagnetic signals, which improves the reliability of detection.

[0021] 4. Achieve multi-point quench positioning and width determination: This solution primarily uses the voltage detected by a superconducting material sensor as the primary criterion for determining quench presence. Optical fiber sensors are also used to determine the location and width of the quench. Established optical fiber temperature measurement uses the time it takes for scattered light to be reflected back to determine the location of the scattering point. The scattered light carries temperature information, allowing the position and temperature along the line to be determined. The quench width is then determined based on the temperature distribution. If multiple quench points are present, the voltage can only be used to calculate the total quench width. However, optical fiber can detect the location of multiple quench points and their corresponding quench widths, enabling both qualitative and quantitative quench detection, a feat unattainable by other detection methods. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The drawings described herein are used to provide a further understanding of the embodiments of the present invention, constitute a part of this application, and do not constitute a limitation of the embodiments of the present invention. In the drawings: Figure 1 Schematic diagram of the structure of a high-temperature superconducting quench detection sensor based on superconducting and optical fiber in Example 1; Figure 2 Schematic diagram of the structure of a high-temperature superconducting quench detection sensor based on superconducting and optical fiber in Example 2; Figure 3 This is a schematic structural diagram of a high-temperature superconducting quench detection sensor based on superconducting and optical fiber in Example 4; Figure 4 This is a structural diagram of a high-temperature superconducting quench detection system in Example 6. DETAILED DESCRIPTION

[0023] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with examples and drawings. The exemplary embodiments of the present invention and their descriptions are only used to explain the present invention and are not intended to limit the present invention.

[0024] Currently, the main high-temperature superconducting quench detection or diagnosis technologies include four categories: (a) line segment sensing; (b) scanning sensing; (c) point sensing; and (d) area sensing.

[0025] (a) Line segment sensing includes: 1. Voltage detection: After a quench occurs, the resistivity of a high-temperature superconducting material increases, generating a voltage across the material. Voltage tapping is widely used in low-temperature superconducting applications. However, when applied to quench detection in high-temperature superconductors, the propagation speed of quenches in high-temperature superconductors is one to two orders of magnitude slower than that of low-temperature superconductors. Therefore, detecting a sufficiently large voltage change takes too long, and by the time a detection is made, the superconducting material has already been damaged. Because high-temperature superconductors contain conductive protective materials, the measured voltage is also very small. The strong magnetic field and electromagnetic environment in which they are located easily induce noise voltages, resulting in a low signal-to-noise ratio.

[0026] 2. Low-temperature superconducting wire detection method: The latest quench detection method uses low-temperature superconducting wire as a detector. When a high-temperature superconductor quenches, a local hotspot causes the temperature of the surrounding low-temperature superconductor to exceed the critical temperature, causing a quench. Because low-temperature superconducting quenches are easier to detect, this method can indirectly detect the quench. While this method can more accurately determine and detect quenches, it can only display the quench across the entire wire segment and cannot pinpoint the quench location.

[0027] (b) Scanning sensors include: 1. Fiber optic scattered light temperature measurement method: By emitting laser light into an optical fiber and detecting the reflected light at different time intervals, temperature and strain can be measured at different locations. Depending on the scattered signal detected, these methods primarily include Raman scattering, Brillouin scattering, and Rayleigh scattering. Because the intensity and frequency of the scattered light are related to the fiber's temperature and strain, the intensity and frequency of the scattered light contain information about temperature and strain. The reflected light is scanned along the fiber to detect the temperature or strain in the superconducting cable. This method can measure the temperature at any location along the fiber path, but it is more difficult to measure in the low-temperature range below 77K used by high-temperature superconductors, where temperature rise is minimal. Crucially, it is impossible to distinguish whether changes in optical frequency are due to stress or temperature fluctuations. In principle, this decoupling and differentiation is impossible, and the measured temperature may not necessarily reflect the actual temperature, leading to misinterpretations.

[0028] 2. Active acoustic temperature measurement method: Similar to the light scattering sensing method, the local temperature is measured by actively emitting sound waves and then analyzing the reflected sound wave information. Since the Young's modulus of the material is related to temperature, and the reflection velocity is related to the Young's modulus, the temperature information can be analyzed from the reflected sound wave. However, this method is difficult to detect accurately because the relative translation of velocity caused by temperature is very small. There are a large number of wave modes in the solid, including compression, shear, torsion and Lamb surface waves, which have a lot of interference and cannot accurately analyze the temperature information. When the size of the system is increased, the proportion of sound waves is reduced due to the influence of thermal wave bodies. Preliminary experiments have shown that for quench detection, the sensitivity of this technology is only effective when the coil length is less than 100m.

[0029] 3. Electromagnetic wave reflection measurement: By emitting electromagnetic wave signals within the conductor, the propagation constant of the superconducting cable and the reflection coefficient at the impedance discontinuity are evaluated, allowing reflection anomalies at the mid-segment quench point to be detected. Typically, a step-frequency waveform or linear frequency modulation signal is used as input. This method is difficult to detect in long-distance cables. If the cable has numerous joints and fault points, signal differentiation and detection becomes difficult. Electromagnetic interference can also have an impact. Multiple reflected signals can easily generate multiple correlation function values with previous signals, leading to confusion about the signal's origin.

[0030] (c). Point sensing 1. Passive acoustic wave emission detection method: Acoustic signal detection is used to detect vibration signals caused by rapid temperature rises due to fractures, delamination, and quenches to determine the operating status of superconducting magnets. However, the sensor has a low signal-to-noise ratio in liquid helium and liquid nitrogen, and the noise from the cooling fluid is relatively high. This poor signal reliability makes it difficult to detect quenches in a timely manner.

[0031] 2. Magnetic flux change detection method: Quench measurement is achieved by using an electronic coil antenna to detect changes in magnetic flux or magnetic field gradient caused by the quench. This method offers fast response and strong signals. However, the detection antenna takes up a lot of space and can only measure magnetic field gradient changes in magnets with strong magnetic field strengths. It is easily affected by other magnetic field fluctuations, and the long lead wires are susceptible to electromagnetic interference. Furthermore, it can only measure magnetic field changes at fixed locations and cannot determine the specific location of the quench.

[0032] 3. Hydraulic and flow detection methods: During normal operation, the coolant flow in a superconducting cable is driven by motors at both ends of the cable, maintaining a nearly constant flow rate. However, when a quench occurs in a superconducting cable, heat accumulation causes the coolant to expand, affecting the interaction between the fluids and causing a change in flow rate. Specific galvanometers or pressure sensors installed at both ends of the superconducting cable detect changes in the coolant flow rate or pressure to determine if a quench has occurred. However, these sensors are slow and are primarily used to detect less severe quench faults.

[0033] 4.FBG grating temperature measurement method: By placing a grating in an optical fiber, a specific wavelength related to the grating period distance is reflected. When the temperature or stress changes, the grating period shifts, causing the reflected wavelength to change. The temperature can be measured by this change, allowing the presence of a quench at a specific point to be detected. However, this method is limited in location and the number of points that can be detected is also limited.

[0034] (d) Area sensing 1. Stray capacitance method: During a quench, the capacitance between the components and the coil changes due to a variety of effects, including changes in the temperature, pressure, density, and state of the cryogenic fluid; changes in the relative dielectric constant of the insulating material; and changes in the distance between components caused by thermal expansion. These changes in stray capacitance are used to detect quenches. However, oversimplifying the magnet parameters makes it difficult to accurately distinguish quench conditions and pinpoint the location of the quench. The magnet is also susceptible to motion, forces, and changes in the surrounding environment.

[0035] When a high-temperature superconductor quenches, its resistance increases instantaneously, and the current is immediately diverted to the protective surrounding conductive layer. The current flowing through the conductor generates a large amount of heat. If this heat is not promptly removed by the cooling medium, the temperature rises sharply, potentially burning the magnet. Therefore, it is crucial to detect the quench as early as possible, accurately diagnose and locate the quench, and promptly implement protective measures such as current reduction.

[0036] According to the introduction of the prior art, the problems to be solved by the present invention mainly focus on: 1. Detection speed lag: Because quench detection and quench protection require limited time, HTS quench diagnosis must detect the quench as early as possible, within milliseconds. This is difficult to achieve with many existing technologies, such as voltage detection, hydraulic and flow detection, and stray capacitance detection.

[0037] 2. Difficulty in signal detection: Since the signal needs to be accurately detected without being interfered by noise and induced current in order to perform subsequent signal analysis, the signal-to-noise ratio and strength of the signal are difficult to meet the requirements of these technologies, such as voltage detection method (usually detectable at the mV level), active acoustic wave temperature measurement method, passive acoustic wave detection method, and fiber optic scattered light temperature measurement method.

[0038] 3. Inaccurate quench determination: Because signals are detected but subject to significant interference or false positives (a quench followed by a return to normal), accurate quench determination is difficult. For example, fiber-scattered signals cannot distinguish between stress and temperature changes, voltage signals are easily affected by magnets and plasma currents, acoustic wave sources are excessive, and electromagnetic wave reflection signals are easily affected by the electromagnetic environment, defects, and joints. These techniques include voltage detection (usually with long-distance leads), active acoustic temperature measurement, passive acoustic temperature measurement, fiber-scattered light temperature measurement, electromagnetic wave reflection measurement, and stray capacitance.

[0039] 4. The quench area is difficult to locate: Even though some methods can determine the quench, such as the low-temperature superconducting wire detection method and the magnetic flux change detection method, these two technologies can only determine whether the quench has occurred in the entire monitored area, and cannot determine the location of the quench.

[0040] In order to solve the above problems, this embodiment 1 provides a high-temperature superconducting quench detection sensor based on superconducting and optical fiber, such as Figure 1 Shown, including: The superconducting material layer is arranged in parallel or side by side with the superconducting transmission cable to be tested to sense the temperature and superconducting state of the superconducting transmission cable to be tested; the superconducting transmission cable to be tested is a high-temperature superconducting transmission cable.

[0041] an optical fiber coaxially arranged with the superconducting material layer, with the length direction of the optical fiber parallel to the length direction of the superconducting material layer, for collecting the temperature of the superconducting material layer and the specific position of each temperature point; The insulating layer wraps the superconducting material layer to prevent the current in the superconducting material layer from being shunted.

[0042] In order for the optical fiber to detect the temperature of the superconducting material layer, there must be good thermal conductivity between the optical fiber and the superconducting material layer.

[0043] like Figure 1As shown, the superconducting material layer, optical fiber and insulating layer are coaxially arranged, and from the inside to the outside they are the optical fiber, the superconducting material layer and the insulating layer. Figure 1 The right side structure is from Figure 1 AA section view of the left structure in .

[0044] The quench detection sensor is designed as a coaxial structure, with a very thin optical fiber in the middle, which serves as the optical path and detector for distributed temperature measurement. The temperature detection principle is based on the commonly used Raman scattering, Brillouin scattering or Rayleigh scattering. It scans and detects by emitting a specific laser, and measures the temperature of the position by detecting the light signal scattered back from different positions. The position of the detected area in the optical fiber can be determined by the time difference between emission and return. A layer of superconducting material is wrapped around the outside of the optical fiber for quench perception and quench judgment. The selection of the superconducting material layer is mainly based on the operating temperature of the superconducting transmission cable. The superconducting shunt critical temperature Tcs of the superconducting detection material (superconducting material layer) needs to be equal to or higher than the operating temperature of the superconducting transmission cable. The temperature or operating temperature To is used. In this way, the selected superconducting detection material can be a low-temperature superconducting material or a high-temperature superconducting material. The intensity of the quench detection signal is positively correlated with the resistivity of the superconducting material under normal conditions. For example, for YBCO-type high-temperature superconducting materials, they are ceramic materials under normal conditions, which are insulating materials with large resistance and can easily detect the corresponding voltage. Since they are wrapped with optical fibers, local heating conditions are formed at the quench position after the quench, which promotes rapid temperature detection of the optical fiber. The outermost layer is an insulating material to prevent the current in the superconducting material from being shunted, thereby reducing the detection voltage. Therefore, the outer insulating layer is critical, which is why the existing high-temperature superconducting materials on the market cannot be directly used for quench detection.

[0045] When a transmission cable quench occurs, the local temperature rise will cause the temperature of the superconducting material (the superconducting material layer of the superconducting quench detection sensor) to rise. When the temperature exceeds (is higher than) the critical temperature of the superconducting detection line (the superconducting material layer is selected according to the temperature condition To used, and the superconducting material layer needs to meet the quench shunt critical temperature Tcs>To. The material used can be a high-temperature superconducting material (usually ceramic, with high resistivity after quench) or a low-temperature superconducting material (usually alloy, with fast quench propagation speed)). At this time, due to the surrounding optical fiber and insulation layer (wrapping material These include low-temperature insulating materials, ceramics, superconducting buffer materials, and glass. The absence of a metal layer to shunt current causes the voltage (current x resistance) across the superconducting detection material to increase. This is because after a quench, the resistivity of the superconducting material in its normal state is much greater than that in its superconducting state, triggering a sudden voltage jump in the detection circuit, reaching a level that can be detected quickly (for example, when a high-temperature superconducting tape quenches, direct voltage measurement requires 500ms to detect a detectable 0.1V signal, while detection using insulated superconducting material only takes about 6ms). This allows for the quench to be determined. This allows more time for quench protection to operate. Optical fibers can detect temperature and strain along the route, and determine the location of detection by the time of round-trip scattering. Since the optical fiber is tightly integrated with the superconducting detection material (via coaxial wrapping or parallel contact), the quench of the superconducting transmission cable causes the surrounding superconducting detection material and the optical fiber to heat up together. If there is no superconducting detection material, the temperature rise detected by the optical fiber will be slower. However, due to the tight integration of the superconducting detection material and the optical fiber, the quench of the superconducting detection material will turn itself into a local heating resistor. The optical fiber at the close heating hotspot position allows the optical fiber to detect a sufficiently large temperature rise faster, thereby determining the quench temperature and quench position earlier and more prominently. The quench of the superconducting detection material (superconducting material layer) promotes the optical fiber's detection of temperature and stress. The specific location of the quench can be determined by comparing the position temperature data before and after the quench. The detection line is the superconducting material in the quench detection sensor. Example 2 like Figure 2 As shown, the superconducting material layer is a wire, and the superconducting material layer and the optical fiber are arranged side by side in the insulating layer to be wrapped by the insulating layer. Figure 2 The right side structure is from Figure 2 BB cross-section view of the left structure in .

[0046] When the superconducting material layer is a wire, the superconducting material layer and the optical fiber are placed side by side and wrapped with insulating material. This system is arranged alongside the superconducting transmission cable to diagnose and locate quenches. This sensor does not require superconducting material coating on the optical fiber surface, simplifies the process, and is suitable for wire-based superconducting materials. The operating principle is similar to that of Example 1.

[0047] Example 3 The superconducting material layer is a wire, the superconducting material layer is wrapped by the insulating layer, and the optical fiber is in contact with the insulating layer. The working principle is similar to that of Example 1.

[0048] Example 4 The superconducting material layer is a tape, and the superconducting material layer and the optical fiber are arranged in parallel in the insulating layer.

[0049] like Figure 3 As shown, when the superconducting material layer is a tape, the superconducting material layer and optical fiber are placed side by side and encased in an insulating layer (insulating material). This entire system is arranged alongside the superconducting transmission cable, enabling quench diagnosis and location. This sensor does not require superconducting material coating on the optical fiber surface, simplifying the process and making it suitable for tape-based superconducting materials. The tape provides a larger contact surface with the superconducting transmission cable, allowing for sensing over a wider area. The operating principle is similar to that of Example 1.

[0050] Example 5 The superconducting material layer is a tape, and the superconducting material layer is arranged in the insulating layer. The optical fiber is arranged in parallel with the superconducting material layer, and the optical fiber is fixed to the outer surface of the insulating layer, that is, after the superconducting material layer is wrapped with insulating material, the optical fiber is bonded to the surface of the insulating material.

[0051] Example 6 Disclosed is a high-temperature superconducting quench detection system for detecting the temperature and voltage on a superconducting transmission cable to be tested to determine whether the superconducting material of the superconducting transmission cable to be tested is quenched. The system comprises the high-temperature superconducting quench detection sensor based on superconducting and optical fiber described in any one of embodiments 1-6, a voltmeter, a detection current source, a transmission current source, and a distributed optical fiber thermometer. The high-temperature superconducting quench detection sensor is placed in parallel and in close contact with the superconducting transmission cable to be tested. Two ends of the high-temperature superconducting quench detection sensor are respectively connected to two ends of the detection current source to form a detection loop; The two ends of the superconducting transmission cable to be tested are respectively connected to the two ends of the transmission current source to form a working loop. The two ends of the voltmeter are respectively connected to the negative ends of the detection current source and the transmission current source, so as to detect the voltage difference obtained after passing through the high-temperature superconducting quench detection sensor and the superconducting transmission cable to be tested in the detection loop and the working loop respectively; The distributed optical fiber thermometer is connected to one end of the high-temperature superconducting quench detection sensor to detect the temperature of the high-temperature superconducting quench detection sensor.

[0052] In some embodiments, the temperature To of the superconducting material layer in the high-temperature superconducting quench detection sensor is lower than the quench shunting critical temperature Tcs of the transmission line to be tested.

[0053] In some embodiments, both ends of the detection current source are respectively connected to the superconducting material layer of the high-temperature superconducting quench detection sensor, both ends of the transmission current source are respectively connected to the superconducting material layer of the superconducting transmission cable to be tested, and the distributed optical fiber thermometer is connected to the optical fiber of the high-temperature superconducting quench detection sensor.

[0054] The detection system primarily consists of two current loops. The left-hand loop carries the operating current (i.e., the current in the working loop is called the operating current) and is powered by a transmission current source. The right-hand loop is the quench detection current loop (detection loop), which is powered by a detection current source, typically a constant current source. The HTS transmission cable and the HTS quench detection sensor are installed in parallel and closely together. Voltage measuring instruments are placed at the ends of the HTS transmission cable and the superconducting material layer to measure the voltage between them to detect quench. This parallel arrangement eliminates induced voltage noise caused by electromagnetic flux variations along the path. Quenching is determined by voltage changes in the superconducting material, while optical fiber is used to further determine the specific quench condition, including temperature rise, quench range, and quench location. Combining and complementing these two approaches yields highly reliable and accurate quench diagnosis results.

[0055] Example 7 Disclosed is a high-temperature superconducting quench detection method, which uses the high-temperature superconducting quench detection system described in Example 6 to detect a superconducting transmission cable to be tested, comprising: Measure the voltage difference between the working circuit and the detection circuit using a voltmeter; Detecting the temperature along the high-temperature superconducting quench detection sensor and the specific position of each temperature point by a distributed optical fiber thermometer; When the voltage difference between the working circuit and the detection circuit measured by the voltmeter increases and exceeds a critical value, it indicates that the superconducting transmission cable to be tested has quenched; and when the temperature of the high-temperature superconducting quench detection sensor detected by the distributed optical fiber thermometer exceeds a set temperature threshold, it also indicates that the superconducting transmission cable to be tested has quenched; The position and width of the quench of the superconducting transmission cable to be tested are determined according to the temperature signal changes at different positions of the distributed optical fiber thermometer before and after the quench.

[0056] It should be noted that the key points of the present invention are as follows: 1. Utilizing the temperature-dependent changes in fiber lasers and the temperature-dependent changes in the superconducting properties of superconducting materials, optical fiber and superconducting materials are combined with insulating materials to form a photo-electric-thermal sensor, achieving coordinated photo-electric and thermal detection. This sensor is arranged in parallel with the monitoring cable (the superconducting transmission cable to be measured), with the three components (the optical fiber, the superconducting transmission cable to be measured, and the superconducting material layer) kept as close as possible to maintain good thermal conductivity. These complementary and mutually reinforcing measurement methods enhance the accuracy and reliability of quench detection. The optical fiber and superconducting sensor material are closely arranged in parallel and in contact, using methods such as proximity and coaxial nesting. Superconducting material voltage detection is primarily used to determine quench presence, offering fast speed and strong signal strength. Optical fiber temperature measurement is primarily used to determine quench location and width. It can determine the quench temperature and location at multiple points along the same line, and can detect the temperature values at corresponding locations using optical time-domain or frequency-domain detection methods. This allows for both qualitative and quantitative characterization of quench conditions.

[0057] Second, the present invention utilizes superconducting materials and surrounds them with a non-shunt insulating layer. Conventional superconducting tapes and wires use metal shunts to prevent the superconducting material from burning after a quench. The present invention utilizes a superconducting sensor material without shunt metal, surrounding it with an insulating or ceramic material (including low-temperature-resistant electrical insulation, ceramics, superconducting buffer materials, and glass). The sensor does not need to transmit high currents or require shunt protection. Once a quench occurs, the sensor's resistance returns from zero to a normal value. The superconducting material is selected based on the operating temperature, To, and must meet the material's critical quench shunt temperature, Tcs, greater than the operating To, ensuring that the high-temperature superconducting quench detection sensor remains superconducting under normal operating conditions. The material can be either a high-temperature superconductor (typically ceramic, which has a high resistivity after a quench) or a low-temperature superconductor (typically an alloy, which has a fast quench propagation speed). Without a surrounding metal shunt, the voltage across the sensor quickly reaches a detectable value (high-temperature superconductors are more effective). Superconducting materials can be in the form of wires, ribbons, or even directly coated on optical fibers. However, they must be surrounded by an insulating cladding material and must not contain any shunt metal. (Commercially available superconducting materials all have metal shunt layers, resulting in very low detection voltages and requiring a very long quench distance to detect voltage.)

[0058] 3. Based on the previous two points (the two sensors are close to each other and the normal-state resistance of the superconducting material is large), the quench of the superconducting material sensor turns the quench position into a small heater, which directly promotes the temperature measurement of the optical fiber at the quench position. The thermal expansion of the superconducting material directly stretches the optical fiber, increasing the frequency shift of the reflected signal and enhancing the signal of the quench temperature detection.

[0059] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A high-temperature superconducting quench detection sensor based on superconducting and optical fiber, characterized in that: include: a superconducting material layer, arranged in parallel or side by side with the superconducting transmission cable to be tested, so as to sense the temperature and superconducting state of the superconducting transmission cable to be tested; an optical fiber, coaxially arranged with the superconducting material layer, or with the length direction of the optical fiber parallel to the length direction of the superconducting material layer, for collecting the temperature of the superconducting material layer and the specific position of each temperature point; The insulating layer wraps the superconducting material layer to prevent the current in the superconducting material layer from being shunted.

2. A high-temperature superconducting quench detection sensor based on superconducting and optical fiber according to claim 1, characterized in that: The superconducting material layer, the optical fiber and the insulating layer are coaxially arranged, and are arranged in order from the inside to the outside.

3. The high-temperature superconducting quench detection sensor based on superconducting and optical fiber according to claim 1, characterized in that: The superconducting material layer is a wire rod, and the superconducting material layer and the optical fiber are arranged side by side in the insulating layer to be wrapped by the insulating layer.

4. The high-temperature superconducting quench detection sensor based on superconducting and optical fiber according to claim 1, characterized in that: The superconducting material layer is a wire, the superconducting material layer is wrapped by the insulating layer, and the optical fiber is in contact with the insulating layer.

5. The high-temperature superconducting quench detection sensor based on superconducting and optical fiber according to claim 1, characterized in that: The superconducting material layer is a tape, and the superconducting material layer and the optical fiber are arranged in parallel in the insulating layer.

6. The high-temperature superconducting quench detection sensor based on superconducting and optical fiber according to claim 1, characterized in that: The superconducting material layer is a tape, and the superconducting material layer is arranged in the insulating layer. The optical fiber is arranged in parallel with the superconducting material layer, and the optical fiber is fixed on the outer surface of the insulating layer.

7. A high-temperature superconducting quench detection system for detecting the temperature and voltage on a superconducting transmission cable to be tested to determine whether the superconducting material of the superconducting transmission cable to be tested is quenched, characterized in that: The method comprises a high-temperature superconducting quench detection sensor based on superconducting and optical fiber, a voltmeter, a detection current source, a transmission current source, and a distributed optical fiber thermometer according to any one of claims 1 to 6, wherein the high-temperature superconducting quench detection sensor is closely attached to the superconducting transmission cable to be tested in parallel. Two ends of the high-temperature superconducting quench detection sensor are respectively connected to two ends of the detection current source to form a detection loop; The two ends of the superconducting transmission cable to be tested are respectively connected to the two ends of the transmission current source to form a working loop. The two ends of the voltmeter are respectively connected to the negative ends of the detection current source and the transmission current source, so as to detect the voltage difference obtained after passing through the high-temperature superconducting quench detection sensor and the superconducting transmission cable to be tested in the detection loop and the working loop respectively; The distributed optical fiber thermometer is connected to one end of the high-temperature superconducting quench detection sensor to detect the temperature of the high-temperature superconducting quench detection sensor.

8. A high-temperature superconducting quench detection system according to claim 7, characterized in that: The operating temperature To of the superconducting transmission cable to be tested is not greater than the quench shunting critical temperature Tcs of the superconducting material layer of the high-temperature superconducting quench sensor, so as to ensure that the high-temperature superconducting quench detection sensor is in a superconducting state under normal working conditions.

9. A high-temperature superconducting quench detection system according to claim 7, characterized in that: The two ends of the detection current source are respectively connected to the superconducting material layer of the high-temperature superconducting quench detection sensor, the two ends of the transmission current source are respectively connected to the superconducting material layer of the superconducting transmission cable to be tested, and the distributed optical fiber thermometer is connected to the optical fiber of the high-temperature superconducting quench detection sensor.

10. A high-temperature superconducting quench detection method, using a high-temperature superconducting quench detection system according to any one of claims 7 to 9 to detect a superconducting transmission cable to be tested, characterized in that: include: Measure the voltage difference between the working circuit and the detection circuit using a voltmeter; Detecting the temperature along the high-temperature superconducting quench detection sensor and the specific position of each temperature point by a distributed optical fiber thermometer; When the voltage difference between the working circuit and the detection circuit measured by the voltmeter increases and exceeds a critical value, it indicates that the superconducting transmission cable to be tested has quenched. If the temperature of the high-temperature superconducting quench detection sensor detected by the distributed optical fiber thermometer exceeds a set temperature threshold, it also indicates that the superconducting transmission cable to be tested has quenched. The position and width of the quench of the superconducting transmission cable to be tested are determined according to the temperature signal changes at different positions of the distributed optical fiber thermometer before and after the quench.

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