Transformer oil temperature measuring method and device based on quantum sensing technology

Abstract

The embodiment of the invention provides a transformer oil temperature measuring method and device based on a quantum sensing technology, and the method comprises the steps: exciting a diamond nitrogen-vacancy color center through laser, and achieving the spin initialization of the diamond nitrogen-vacancy color center; while the laser is applied, sweep frequency microwaves are applied to the diamond nitrogen-vacancy color center so as to regulate and control the spinning state of the diamond nitrogen-vacancy color center; detecting a fluorescence signal emitted by the diamond nitrogen-vacancy color center under the action of laser and sweep frequency microwaves; generating an optical detection magnetic resonance curve based on the fluorescence signal, wherein the optical detection magnetic resonance curve represents the change of the fluorescence intensity along with the microwave frequency; extracting a zero field splitting value from the optical detection magnetic resonance curve; according to the extracted zero field splitting value, the corresponding transformer oil temperature is obtained based on the function relation between the preset zero field splitting value and the temperature. According to the technical scheme provided by the invention, high-precision and high-stability transformer oil temperature measurement can be realized.

Description

Technical Field

[0001] This invention belongs to the field of transformer oil temperature measurement technology, and particularly relates to a transformer oil temperature measurement method and device based on quantum sensing technology. Background Technology

[0002] In the field of power equipment condition monitoring, accurate measurement of transformer oil temperature is crucial for ensuring the safe and stable operation of the power grid. Transformers are core equipment in the power grid, and their oil temperature directly reflects the insulation condition and load capacity. Abnormal oil temperature can lead to insulation aging, partial discharge, and even explosions due to faults. Therefore, high-precision, real-time monitoring is of great significance for accident prevention. The limitations of traditional methods have spurred the demand for new technologies such as quantum sensing. Currently, traditional oil temperature measurement technologies mainly rely on two types of methods, but these methods have significant limitations in the complex operating environment of transformers. The internal environment of transformers is harsh, including strong electromagnetic fields (electric field strength at 50Hz power frequency can reach kV / m levels), drastic temperature changes (-40℃ to 100℃), chemical corrosion (sulfides in the oil), and mechanical vibration. Traditional methods struggle to maintain accuracy under such multi-physics coupling conditions, while NV color center technology, with its atomic-level stability and anti-interference capabilities, holds promise for overcoming these bottlenecks.

[0003] In existing technologies, a widely used type of temperature sensor is the contact-type temperature sensor based on electrical principles, such as thermocouples and resistance temperature detectors (RTDs). These sensors are directly immersed in transformer oil and indirectly calculate the temperature by sensing changes in their own electrical parameters (such as resistance or potential). However, thermocouples are based on the Seebeck effect, and RTDs are based on the temperature coefficient of resistance of metals, but their electrical signals are susceptible to interference: for example, electromagnetic induction current can be superimposed on the measurement signal, leading to increased errors; and their response time is slow (the thermal time constant is often on the order of seconds), making it impossible to capture transient fluctuations in oil temperature (such as microsecond-level temperature rises caused by partial discharge). Furthermore, the strong power frequency electromagnetic field and potential transient electromagnetic interference present inside the transformer during operation can severely couple into the sensor's electrical signal, causing measurement deviations and drift. In addition, these sensors have a slow response speed, making it difficult to capture rapid fluctuations in oil temperature in real time, and they are prone to aging after long-term use, requiring periodic shutdowns for calibration, resulting in high maintenance costs and affecting the continuity of power supply.

[0004] Another type of technology is optical thermometry, such as measurements based on fluorescence lifetime or fluorescence intensity ratio. While these methods offer some resistance to electromagnetic interference, their sensing mechanisms typically rely on the overall macroscopic physical properties of the fluorescent material. Optical methods utilize the temperature dependence of fluorescent materials (such as rare-earth-doped optical fibers), but their macroscopic properties are easily affected by the fabrication process: for example, the fluorescence lifetime method is limited by material inhomogeneity, with an accuracy of only ±0.5℃; the fluorescence intensity ratio method relies on the intensity ratio of two fluorescence peaks and is easily affected by light source fluctuations and detector drift. In practical applications, ambient stray light, fiber bending loss, and degradation of the fluorescent material itself can introduce significant measurement noise, leading to poor repeatability and long-term stability of the measurements. Their accuracy is easily affected by various environmental factors, making reliable high-precision measurements difficult to achieve in complex media such as transformer oil. Impurities in transformer oil can scatter or absorb fluorescence signals, reducing the signal-to-noise ratio; fluorescent materials are prone to hydrolysis or photobleaching in high-temperature oil, significantly shortening their lifetime. As atomic-level defects, NV color centers originate from energy level structures and are not affected by macroscopic degradation. Furthermore, they can be miniaturized and designed to resist environmental interference through fiber optic packaging. Summary of the Invention

[0005] The transformer oil temperature measurement method and device based on quantum sensing technology provided in this application can achieve high-precision and high-stability transformer oil temperature measurement.

[0006] In a first aspect, embodiments of this application provide a method for measuring transformer oil temperature based on quantum sensing technology, including:

[0007] Spin initialization of diamond nitrogen-vacancy centers was achieved by using laser to excite them.

[0008] While applying laser light, a frequency-sweeping microwave is applied to the diamond nitrogen-vacancy center to modulate the spin state of the diamond nitrogen-vacancy center.

[0009] Detection of fluorescence signals emitted by nitrogen-vacancy color centers in diamond under the action of laser and frequency-sweeping microwave;

[0010] Photodetector magnetic resonance curves are generated based on fluorescence signals, and the photodetector magnetic resonance curves represent the change of fluorescence intensity with microwave frequency.

[0011] Zero-field splitting values ​​were extracted from optically detected magnetic resonance curves.

[0012] Based on the extracted zero-field splitting value, the corresponding transformer oil temperature is obtained according to the predetermined functional relationship between the zero-field splitting value and temperature.

[0013] In one alternative implementation, extracting the zero-field splitting value from the optically probed magnetic resonance curve includes:

[0014] The zero-field splitting value is obtained by identifying the point of lowest fluorescence intensity in the optically detected magnetic resonance curve.

[0015] In one alternative implementation, the predetermined zero-field splitting value is a polynomial fitting model as a function of temperature.

[0016] In one alternative implementation, the polynomial fitting model is obtained through multiple experimental calibrations, the calibration process of which includes measuring the zero-field splitting value at different known temperatures and establishing a mapping relationship.

[0017] Secondly, embodiments of this application provide a transformer oil temperature measuring device based on quantum sensing technology, comprising:

[0018] Optical path module, microwave module, and data acquisition module;

[0019] The optical path module includes a laser source and a photodetector. The laser source is used to generate excitation light, and the photodetector is used to receive fluorescence signals.

[0020] The microwave module includes a microwave source and a microwave antenna. The microwave source is used to generate sweeping microwaves, and the microwave antenna is used to radiate sweeping microwaves.

[0021] The data acquisition module includes a data acquisition card and a microcomputer system. The data acquisition card is connected to the photodetector, and the microcomputer system is connected to the data acquisition card.

[0022] In one alternative implementation, the optical path module further includes an optical fiber that connects the laser source and the photodetector for transmitting excitation light.

[0023] In one alternative implementation, the optical path module further includes an optical fiber circulator disposed in an optical fiber for unidirectional transmission of excitation light to the diamond nitrogen-vacancy color center.

[0024] In one alternative implementation, the optical path module further includes a filter, which is disposed in the incident optical path of the photodetector to filter out stray light.

[0025] In one alternative implementation, the microwave module further includes a power amplifier connected to the microwave source and the microwave antenna for amplifying the power of the swept microwave.

[0026] In one alternative implementation, the microwave module further includes a circulator disposed between the microwave source and the power amplifier to prevent microwave signal feedback.

[0027] In one alternative implementation, the microwave antenna is integrated into the probe structure, which is in direct contact with the transformer oil.

[0028] In one alternative implementation, the probe structure further includes a diamond nitrogen-vacancy color center, which is fixed inside the probe.

[0029] In one alternative implementation, the excitation light is a green laser with an emission wavelength of 532 nm.

[0030] In one alternative implementation, the microcomputer system is equipped with control software that controls the frequency sweep parameters of the microwave source and displays the optical detection magnetic resonance curve in real time.

[0031] In one alternative implementation, the control software also stores a predetermined functional relationship between the zero-field splitting value and temperature, used to automatically calculate the temperature value of the transformer oil.

[0032] Thirdly, embodiments of this application provide an electronic device, including a memory and a processor, wherein the memory stores a computer program, and when the processor executes the computer program, it implements the method provided in embodiments of this application.

[0033] Fourthly, embodiments of this application provide a computer-readable storage medium, characterized in that it stores a computer program thereon, which, when executed in a computer, causes the computer to perform the method provided in embodiments of this application.

[0034] The technical solution provided in this application has the following beneficial effects:

[0035] This invention utilizes the high temperature sensitivity of the zero-field splitting value of the nitrogen-vacancy (NV) color center in diamond. Spin initialization is achieved through laser excitation, and a swept-frequency microwave resonant interaction is used to induce the spin state. Optical Detection Magnetic Resonance (ODMR) curves are plotted by detecting changes in fluorescence intensity. The microwave frequency corresponding to the trough of this curve is the zero-field splitting value. As an atomic-scale energy level parameter, the zero-field splitting value is directly and stably affected by temperature, avoiding the electromagnetic interference and signal drift problems of traditional electrical sensors, thus significantly improving measurement accuracy. Through a module... The design optimizes the signal-to-noise ratio and stability of the signal link. The fiber optic circulator in the optical path module ensures unidirectional transmission of the excitation light and prevents backlight interference. The filter effectively filters out ambient stray light, ensuring the purity of the fluorescence signal. The power amplifier and circulator in the microwave module ensure that the microwave signal applied to the NV color center has sufficient power and is stable without feedback, ensuring the effectiveness of resonance modulation. The data acquisition module, through the combination of hardware and software, realizes the real-time generation of ODMR curves and the automatic extraction of zero-field splitting values, ultimately achieving high-precision, high-stability, and strong anti-interference quantum measurement of transformer oil temperature. Attached Figure Description

[0036] Figure 1 This is a schematic flowchart of the transformer oil temperature measurement method based on quantum sensing technology provided in the embodiments of this application;

[0037] Figure 2 This is a schematic diagram of the photodetector magnetic resonance curve obtained at a temperature of 50°C, provided in an embodiment of this application.

[0038] Figure 3 This is a schematic diagram of the structure of the transformer oil temperature measuring device based on quantum sensing technology provided in the embodiments of this application. Detailed Implementation

[0039] The present application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0040] This application provides a method for measuring transformer oil temperature based on quantum sensing technology. Figure 1 This is a schematic flowchart of a transformer oil temperature measurement method based on quantum sensing technology provided in an embodiment of this application. The method can be executed by a transformer oil temperature measurement device based on quantum sensing technology. The device includes software and / or hardware and can be configured in electronic devices such as computers.

[0041] Nitrogen-vacancy (NV) color centers in diamond are lattice defect structures formed by the substitution of a carbon atom with a nitrogen atom, creating a vacancy in the adjacent carbon atom. This substitution defect leads to the breaking of local lattice symmetry, resulting in a localized energy level structure. (The last sentence appears to be incomplete and possibly refers to a specific type of diamond color center.) 3 Hybrid orbitals provide a rigid host environment for NV centers, enabling them to have long spin coherence times (down to the millisecond level at room temperature), which is the physical basis for their use as quantum sensors. Typically, NV centers have two charge states: the negatively charged NV... - and NV exhibiting electrical neutrality 0 Due to NV - Electrons in NV electrons are easier to polarize and control, therefore, in practical applications, NV electrons are often used. - Mainly. NV - Compared to NV 0 An additional trapped electron forms a ground triplet state with spin S=1, whose energy level can be polarized and initialized by optical pumping; while NV 0 The charge states lack stable spin polarization paths, making them difficult to use for quantum manipulation. NV - The ground state energy level exhibits a split (D value) of 2.87 GHz under zero field. This split is sensitive to physical quantities such as temperature and strain and is a core parameter of quantum sensing.

[0042] As a solid-state quantum functional structure, it possesses excellent properties such as long spin coherence time, all-optical spin initialization, and readout, and has been widely used in the development of various sensing technologies. The long coherence time allows for multiple quantum operations, improving the measurement signal-to-noise ratio; all-optical initialization and readout refer to the ability to prepare spins using only a 532 nm laser. The NV center (NV center) utilizes its spin-dependent fluorescence intensity to achieve non-destructive spin state detection. These properties enable highly sensitive detection of physical quantities such as magnetic fields, temperature, and electric fields at room temperature. Currently, the commonly used energy level structure for NV centers is the three-level structure model. NV centers have a spin triplet ground state, which is... and m s The spin magnetic quantum number describes the state of spin direction in the absence of an external magnetic field. It is degenerate, and and There exists a zero-field splitting value (D) of 2.87 GHz. The excited states of the NV color center are also spin triplet states. and There is a zero-field splitting value of 1.42 GHz. The excited-state splitting value is relatively small, mainly affecting the fluorescence branching ratio, but contributing little to temperature measurement. The advantage of the ground-state D value as a temperature sensing parameter lies in its large value and high temperature sensitivity. When the NV color center is pumped by a laser, the electron in the ground state will transition to the excited state, and its fluorescence spectrum will produce two peaks, corresponding to the spin triplet state. and Transition. Normally, its fluorescence spectrum can be obtained using optically detected magnetic resonance (ODMR). With continuous laser application, by additionally applying a frequency-sweeping microwave, the transition occurs when the microwave frequency matches its... and When the zero-field splitting value D between them is equal, resonance will occur. At this time, the number of photons generated will be lower than the number of photons generated by the transition in non-resonance, and the fluorescence intensity will decrease.

[0043] When using the spin quantum states of NV color centers for quantum sensing, a Hamiltonian formula is typically used to describe the energy state of the NV color centers. This formula incorporates the influence of physical quantities such as electric field, magnetic field, and temperature field on the energy state, corresponding to changes in its spin state. By observing the altered spin state using specific methods, these physical quantities can be measured. Regarding temperature, changes in external temperature indirectly affect the energy state by altering the zero-field splitting value. In the absence of external electromagnetic interference, the Hamiltonian will only be affected by the zero-field splitting value. Therefore, research on temperature measurement using NV color centers usually focuses on measuring the shift in the zero-field splitting value.

[0044] like Figure 1 As shown, the technical solution provided in this application includes the following steps:

[0045] S110. Using laser to excite diamond nitrogen-vacancy color centers to achieve spin initialization of diamond nitrogen-vacancy color centers.

[0046] Specifically, a diamond nitrogen-vacancy (NV) color center is a solid-state quantum defect structure formed by replacing a carbon atom in the diamond lattice with a nitrogen atom and creating a nearby vacancy. In practical applications, negatively charged NV centers are often used. - Color centers are the primary focus because their electron spins are easier to polarize and control, and they have longer spin coherence times and all-optical initialization characteristics, which lay the foundation for high-precision quantum sensing.

[0047] In some embodiments, firstly, a laser source in the optical path module generates excitation light of a specific wavelength, typically a green laser with a wavelength of 532 nm. This wavelength is chosen based on the energy level structure characteristics of the NV centers, which effectively excite electrons in the ground state to higher energy levels. When the laser irradiates a diamond material containing NV centers, electrons in the ground triplet state (…) and Electrons in a molecule absorb energy from photons, causing a transition from the ground state to an excited state.

[0048] The excited state is also a spin triplet state. Because the excited state's The spin quantum state first transitions to a metastable state via nonradiative transition, and then returns to the ground state via spontaneous emission. The entire process lasts longer than the excited state. Spontaneous emission transition back to the ground state The time of the state. This differentiated relaxation dynamics leads to the natural occurrence of spin polarization. After several laser excitation-emission cycles, regardless of the initial spin state of the electron, it will eventually be effectively "pumped" and accumulated to the ground state through an effect known as "optical pumping". At the sub-level. Therefore, under continuous laser irradiation, the spin state of the NV color center set is "initialized" to the sub-level. This step prepares the NV center to a state with the highest fluorescence emission intensity, thus creating conditions for subsequent detection of spin state changes (i.e., the ODMR effect) through changes in fluorescence intensity.

[0049] S120. While applying laser light, a sweeping microwave is applied to the diamond nitrogen-vacancy center to modulate its spin state.

[0050] In some embodiments, the microwave module begins operation while a 532nm laser (used to maintain spin polarization and excite fluorescence) is continuously applied. The microwave source generates a microwave signal with a continuously varying frequency, i.e., a swept microwave. The frequency range of this swept microwave is carefully designed to completely cover the ground state energy level of the NV color center. and The zero-field splitting value D and its possible drift within the expected temperature range are determined. The swept microwave is amplified by a power amplifier and then transmitted to the microwave antenna via a circulator (whose function is to prevent the microwave signal from being reflected back to the microwave source, protect the equipment, and maintain signal stability).

[0051] Subsequently, the microwave antenna radiates amplified swept microwaves onto the diamond containing the NV color center. At this point, the NV color center is simultaneously affected by both the laser field and the microwave field. The physical essence of this is the interaction between the microwave magnetic field and the spin magnetic moment of the NV color center. When the frequency v of the swept microwave is close to the ground state of the NV color center... and When the energy difference between energy levels (i.e., the zero-field splitting value D) is equal, the resonance condition is satisfied: v = D. At the resonance point, the NV color center absorbs the energy of microwave photons, resulting in a state where... Electrons in the excited state undergo a transition to the excited state. state.

[0052] Figure 2 This is a schematic diagram of the photodetector magnetic resonance curve obtained at a temperature of 50°C, as provided in an embodiment of this application. The zero-field splitting value is approximately 2.894 GHz. Figure 2 The optically detected magnetic resonance curves shown visually illustrate this resonance effect. When the microwave frequency sweeps across the resonance point D, electrons are excited to... In this state, the fluorescence emission mechanism changes (as described in S110, this state has a lower fluorescence yield), resulting in a significant decrease (trough) in the detected fluorescence intensity. Conversely, when the microwave frequency is far from the resonance frequency, the spin state of the NV color center is not affected by the microwave, and most electrons remain in the state of resonant electrons. The fluorescence intensity remains at a high level because it is in a certain state.

[0053] S130. Detect the fluorescence signal emitted by diamond nitrogen-vacancy color centers under the action of laser and frequency sweeping microwave.

[0054] In some embodiments, when the frequency of the sweeping microwave satisfies the resonance condition, some NV color centers move from... The state is excited to State. As described in S110, in The color center of the state relaxes back to the ground state through a path involving nonradiative transitions, and the number of fluorescent photons emitted per unit time is significantly less than that emitted when the state remains in the ground state. The NV color center. The resonance condition refers to the microwave frequency v being equal to the splitting value D of the ground state energy level of the NV color center (i.e., v=D). At this time, the microwave field drives the NV color center from a state with high fluorescence efficiency. State transition to low fluorescence efficiency State. Due to The state relaxes through a nonradiative transition path (via a metastable state), and its fluorescence quantum yield is higher than that of the state. The low state leads to a significant decrease in fluorescence intensity at the resonance point. Therefore, the fluorescence intensity received by the detector changes dynamically during microwave frequency scanning. The fluorescence emitted by the NV color center is red fluorescence with a wavelength of approximately 637 nm. The dynamic change in fluorescence is a direct manifestation of the ODMR effect: when scanning microwave frequencies, fluorescence quenching (trough) only occurs at v=D, while the fluorescence intensity remains high at other frequencies.

[0055] In some embodiments, this detection step is completed collaboratively by the optical path module and the data acquisition module. First, the red fluorescence emitted by the diamond NV color center is collected by the same optical fiber used to transmit the excitation light, achieving reverse transmission of the optical signal. As the optical signal propagates in the optical fiber, it passes through a filter. The filter's function is to remove stray light other than the 637nm red light emitted by the diamond, such as ambient light or laser scattering light, thereby ensuring the purity of the optical signal entering the detector and significantly improving the signal-to-noise ratio.

[0056] In some embodiments, the filtered, purified fluorescence signal is then received by a photodetector. The photodetector is the core sensing element of the optical path module, used to receive the 637nm red light emitted by the diamond and convert the optical signal into a voltage signal. This process completes the conversion from photons to electrons, linearly converting the weak fluorescence intensity change into a voltage signal change. This voltage signal is an analog electrical signal that directly reflects the relationship between microwave frequency and spin resonance.

[0057] S140. Generate a photodetector magnetic resonance curve based on the fluorescence signal. The photodetector magnetic resonance curve represents the change of fluorescence intensity with microwave frequency.

[0058] In some embodiments, the analog voltage signal output by the photodetector, which is proportional to the fluorescence intensity, is first transmitted to a data acquisition card. Shielded cables are used for voltage signal transmission to prevent electromagnetic interference from introducing noise. The data acquisition card samples and performs analog-to-digital conversion on the continuous voltage signal at extremely high rates, transforming it into a discrete, computer-processable digital sequence. The converted digital sequence is then pre-processed by an FIR digital filter to suppress high-frequency noise.

[0059] Meanwhile, the microcomputer system controlling the microwave source records the microwave frequency value at each moment. The control software running on the microcomputer system synchronizes the frequency sweeping process of the microwave source with the signal acquisition process of the data acquisition card. That is, for each emitted microwave frequency v, the software synchronously records the average fluorescence intensity I collected at that frequency point.

[0060] The software then plots a series of data points (v, I) in a coordinate system, where the horizontal axis represents the scanning microwave frequency and the vertical axis represents the synchronously acquired fluorescence intensity or normalized fluorescence count rate. For example, normalization may include dividing the original fluorescence intensity I by the laser power or background noise value to eliminate the influence of light source fluctuations. The coordinate system uses a linear scale, with the horizontal axis covering 2.86–2.90 GHz and the vertical axis automatically scaled to highlight resonance troughs. Connecting these data points yields a relationship between microwave frequency and fluorescence intensity, i.e., a photodetector magnetic resonance curve. Curve fitting (such as Lorentz function fitting) is preferred over nonlinear interpolation to reproduce the physically accurate resonance profile.

[0061] S150, Extract the zero-field splitting value from the optically detected magnetic resonance curve.

[0062] Continue to refer to Figure 2 As can be seen, at most microwave frequencies, the fluorescence intensity remains at a high level, corresponding to the non-resonant case; however, when the microwave frequency sweeps through a certain value (i.e., the zero-field splitting value D), the fluorescence intensity drops sharply due to magnetic resonance, forming a distinct trough.

[0063] Specifically, the physical mechanism of the decrease in fluorescence intensity is as follows: when the microwave frequency satisfies the resonance condition (v=D), stimulated transitions occur between the ground state sublevels of the NV color center, and electrons transition from the high fluorescence efficiency... State transfer to low fluorescence efficiency This state leads to a decrease in overall fluorescence yield. The depth and width of the trough depend on spin polarization, microwave field strength, and ambient noise level.

[0064] Figure 2The ODMR curve shown is a typical Lorentz curve, and its trough symmetry is affected by crystal strain and electric field. In practical applications, noise needs to be suppressed by multiple scan averaging or digital filtering (such as Savitzky-Golay filter) to ensure that the trough characteristics are clearly distinguishable.

[0065] Therefore, the microwave frequency corresponding to this trough is the zero-field splitting value D extracted under the current environment.

[0066] For example, the extraction method includes:

[0067] Direct valley finding method: scans the frequency corresponding to the minimum fluorescence intensity, suitable for high signal-to-noise ratio scenarios;

[0068] Curve fitting method: The ODMR curve is fitted using the Lorentz function or Gaussian function. The trough frequency is accurately determined by the fitting parameters. This method can overcome noise interference and achieve an accuracy of 0.1MHz.

[0069] Furthermore, the accuracy can be further improved by performing temperature compensation correction on the extracted D value, for example, by eliminating short-term drift through reference sensor or environmental monitoring data.

[0070] S160. Based on the extracted zero-field splitting value, the corresponding transformer oil temperature is obtained according to the predetermined functional relationship between the zero-field splitting value and temperature.

[0071] Specifically, the zero-field splitting value D of the NV color center exhibits a strong temperature dependence. Its ground-state zero-field splitting value D is typically obtained using photodetector magnetic resonance (PDMR) technology. At room temperature, its zero-field splitting value D = 2.87 GHz. When the external temperature changes, its zero-field splitting value D changes accordingly, which is reflected in the overall shift of the PDMR curve. Using a laser, the zero-field splitting value D in its ground state can be obtained... and The states are pumped to the excited states respectively. and Spin quantum state. Because of excited state The spin quantum state first transitions to a metastable state via nonradiative transition, and then returns to the ground state via spontaneous emission. The entire process lasts longer than the excited state. Spontaneous emission transition back to the ground state The time of the state is relatively short, and the number of fluorescent photons emitted per unit time is small, so the number of photons can be used to determine the state. and Spin quantum state.

[0072] In the experiment, the zero-field light-probe magnetic resonance spectrum was obtained by sweeping the frequency around a microwave frequency of approximately 2.87 GHz. First, a laser was used to excite the color center to an excited state, and then fluorescence emission or non-radiative transitions were used to bring the color center to a new excited state. The state is then used to achieve spin initialization of the NV color center. Then, the ground state is... A sweeping microwave within a certain frequency range is applied to the state. At resonance, The particles will be excited to At higher temperatures, the fluorescence count rate will be lower than at non-resonance temperatures, thus yielding a photodetector magnetic resonance curve. The lowest point of the curve is the zero-field splitting value D. By experimentally measuring the zero-field splitting value D at different temperatures, a curve showing the relationship between the zero-field splitting value D and temperature can be obtained. This curve can be used to fit a functional relationship between temperature and the zero-field splitting value, allowing for the measurement of transformer oil temperature using the zero-field splitting value D.

[0073] In summary, this invention utilizes the high temperature sensitivity of the zero-field splitting value of the nitrogen-vacancy (NV) color center in diamond. Spin initialization is achieved through laser excitation, and a swept-frequency microwave resonant interaction with the spin state is used. Optical Detection Magnetic Resonance (ODMR) curves are plotted by detecting changes in fluorescence intensity. The microwave frequency corresponding to the trough of this curve is the zero-field splitting value. As an atomic-scale energy level parameter, the zero-field splitting value is directly and stably affected by temperature, avoiding the electromagnetic interference and signal drift problems of traditional electrical sensors, thus significantly improving measurement accuracy. Modular design optimizes the signal-to-noise ratio and stability of the signal link. The fiber optic circulator in the optical path module ensures unidirectional transmission of excitation light and prevents backlight interference. The filter effectively filters out ambient stray light, ensuring the purity of the fluorescence signal. The power amplifier and circulator in the microwave module ensure that the microwave signal applied to the NV color center has sufficient power and is stable without feedback, ensuring the effectiveness of resonance modulation. The data acquisition module, through the combination of hardware and software, realizes the real-time generation of ODMR curves and the automatic extraction of zero-field splitting values, ultimately achieving high-precision, high-stability, and strong anti-interference quantum measurement of transformer oil temperature.

[0074] Figure 3 This is a schematic diagram of the structure of the transformer oil temperature measuring device based on quantum sensing technology provided in the embodiments of this application, as shown below. Figure 3 As shown, the device includes: an optical path module, a microwave module, and a data acquisition module;

[0075] The optical path module includes a laser source and a photodetector. The laser source is used to generate excitation light, and the photodetector is used to receive fluorescence signals.

[0076] In some embodiments, the laser source can be a semiconductor-pumped solid-state laser (DPSS) that outputs 532nm green laser light to match the zero-phonon line absorption peak (637nm) of the NV color center, ensuring efficient spin initialization. The photodetector can be an avalanche photodiode (APD) because of its high gain (>100) and low noise characteristics, which can detect single-photon level fluorescence signals and improve the signal-to-noise ratio.

[0077] The microwave module includes a microwave source and a microwave antenna. The microwave source is used to generate sweeping microwaves, and the microwave antenna is used to radiate sweeping microwaves.

[0078] In some embodiments, the microwave source needs to have high frequency stability (phase noise <-110 dBc / Hz) and a wide sweep range (typically covering 2.86-2.90 GHz) to capture the zero-field splitting value D drift with temperature. The microwave antenna can be designed as a microstrip line or a ring structure, with impedance matched to 50Ω to ensure that the microwave field is uniformly radiated to the NV color center region and to avoid standing wave interference.

[0079] The data acquisition module includes a data acquisition card and a microcomputer system. The data acquisition card is connected to the photodetector, and the microcomputer system is connected to the data acquisition card. After data is acquired through the data acquisition card, it can be processed and analyzed in real time in the host computer software.

[0080] In some embodiments, the optical path module further includes an optical fiber that connects the laser source and the photodetector for transmitting excitation light.

[0081] In some embodiments, the optical path module further includes a fiber optic circulator. This device integrates the circulator within a single optical fiber to prevent the green laser emitted from the laser source from returning to the photodetector, ensuring unidirectional optical transmission. Exemplarily, the fiber optic circulator is based on the Faraday rotation effect, providing isolation >50 dB, preventing the 532nm excitation light from backscattering to the detector and avoiding saturation or damage. This design simplifies the optical path and avoids the complexity of traditional beam splitters.

[0082] In some embodiments, the optical path module further includes a filter, which is disposed in the incident optical path of the photodetector to filter out stray light other than the 637nm red light emitted by the diamond, ensuring the accuracy of the sensing. The filter can be a bandpass filter (center wavelength 637nm, bandwidth ±10nm) to block ambient light (such as background fluorescence in transformer oil) and laser scattered light, thereby further improving the signal-to-noise ratio.

[0083] In some embodiments, the filter can be tilted (angle < 5°) to further suppress reflected stray light.

[0084] In some embodiments, the microwave module further includes a power amplifier connected to the microwave source and the microwave antenna, used to amplify the power of the swept microwave to prevent the power emitted by the microwave source from being too low and affecting the control of the NV color center quantum state.

[0085] In some embodiments, the microwave module further includes a circulator disposed between the microwave source and the power amplifier to prevent microwave signal feedback, primarily serving to protect the microwave source. The circulator is a three-port non-reciprocal device that uses ferrite material to guide unidirectional microwave transmission (isolation >20dB), preventing reflected power from damaging the microwave source. Its insertion loss is <0.5dB, ensuring efficient signal transmission.

[0086] In some embodiments, the microwave antenna is integrated into the probe structure, and the probe structure is in direct contact with the transformer oil.

[0087] In some embodiments, the probe structure further includes a diamond nitrogen-vacancy color center, which is fixed inside the probe. The position of the diamond nitrogen-vacancy color center is precisely aligned with the microwave antenna and the fiber end face to ensure that the optical path overlaps with the microwave field.

[0088] In some embodiments, the excitation light is a green laser with an emission wavelength of 532 nm. The 532 nm laser is the most efficient pump source for NV color centers because its energy is higher than the zero phonon line (637 nm), allowing for spin polarization through non-resonant excitation. Exemplarily, the laser power can be set to 1-10 mW to avoid thermal damage to the diamond (temperature rise <1°C).

[0089] In some embodiments, the microcomputer system is equipped with control software, which is used to control the frequency sweep parameters of the microwave source and display the optically detected magnetic resonance curve in real time. The control software allows users to set the frequency sweep speed (e.g., 1 MHz / ms), step size (e.g., 0.1 MHz), and range, and displays the ODMR curve in real time and automatically fits the troughs.

[0090] Furthermore, the control software can also integrate PID algorithms to dynamically adjust microwave power to compensate for temperature-induced D-value drift.

[0091] In some embodiments, the control software also stores a predetermined functional relationship between the zero-field splitting value and temperature, which is obtained through calibration experiments and used to automatically calculate the temperature value of the transformer oil.

[0092] After the equipment is started, the control software can be used to control the frequency sweep of the microwave source. Both the sweep speed and the sweep step size can be controlled within the software. Simultaneously, the software can be used to plot photodetector magnetic resonance curves in real time and locate the corresponding zero-field splitting value. Before conducting the experiment, the functional relationship between the zero-field splitting value and temperature needs to be obtained using the above method. Given the ambient temperature, the zero-field splitting value at that temperature is obtained by plotting the photodetector magnetic resonance curve. Multiple experiments at different temperatures are conducted to obtain the fitted functional relationship between the two. Once this functional relationship is obtained and incorporated into the program, the corresponding temperature value can be obtained given the zero-field splitting value.

[0093] The execution process of the system part of this application embodiment is the same as that of the method part of the embodiment described above, and will not be repeated here.

[0094] The transformer oil temperature measuring device based on quantum sensing technology provided in this embodiment achieves high-precision, high-stability, and strong anti-interference temperature measurement by integrating optical path, microwave, and data acquisition modules. Based on quantum physics principles and modular design, it solves the limitations of traditional sensors in complex environments.

[0095] The optical module utilizes laser excitation and fluorescence collection technology. It initializes the spin of the NV color center using a specific wavelength of green laser and captures the fluorescence signal with a high-sensitivity photodetector. Combined with fiber optic transmission, unidirectional light guidance via a circulator, and stray light filtering, based on the principle of photonic quantum transition, it ensures signal excitation efficiency and collection purity, thereby improving the signal-to-noise ratio and measurement sensitivity, and avoiding environmental stray light interference. The microwave module modulates the spin state of the NV color center through frequency sweeping microwaves. With the aid of power amplification and circulator isolation feedback, based on the principle of magnetic resonance, it precisely matches the zero-field splitting value. The microwave antenna is integrated into the probe to ensure uniform microwave field radiation, making resonance detection stable and reliable, effectively suppressing electromagnetic interference, and ensuring measurement accuracy in strong magnetic field environments. The data acquisition module uses a high-speed acquisition card and intelligent software to synchronously control microwave frequency sweeping and signal processing. Based on real-time ODMR curve fitting and temperature mapping algorithms, it automatically extracts the zero-field splitting value and inverts the temperature. The software integrates adaptive compensation functions to dynamically optimize parameters, achieving fully automated measurement and significantly enhancing long-term stability and ease of operation.

[0096] In summary, this device combines the atomic-level stability of NV color centers with engineering practicality through quantum sensing mechanisms and modular packaging. It is suitable for monitoring harsh environments such as transformer oil temperature, ultimately achieving high reliability, anti-interference, and miniaturization, thus promoting the application of quantum technology from the laboratory to industrial applications.

[0097] This application also provides an electronic device, including: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, the instructions being executed by the at least one processor to enable the at least one processor to perform the method provided in this application.

[0098] This application also proposes a computer storage medium storing a computer program, which, when executed by a processor, implements the method provided in this application.

[0099] Computer storage media may be simply referred to as media. Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. Any references to memory, storage, databases, or other media used in the embodiments provided in this application may include non-volatile and / or volatile memory. Non-volatile memory may include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memory may include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in various forms, such as Static RAM (SRAM), Dynamic RAM (DRAM), Synchronous DRAM (SDRAM), Dual Data SDRAM (DDRSDRAM), Enhanced SDRAM (ESDRAM), Synchlink DRAM (SLDRAM), Rambus Direct RAM (RDRAM), Direct Memory Bus Dynamic RAM (DRDRAM), and Memory Bus Dynamic RAM (RDRAM). The various embodiments described in this specification are presented in a progressive manner, and similar or identical parts between embodiments can be referred to interchangeably. Each embodiment focuses on describing the differences from other embodiments. In particular, for embodiments of apparatus, devices, and non-volatile computer storage media, since they are substantially similar to the method embodiments, the description is relatively simple, and relevant parts can be referred to the description of the method embodiments.

[0100] The above embodiments are merely illustrative examples and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations. However, obvious variations or modifications derived therefrom are still within the scope of protection of this application.

Claims

1. A method for measuring transformer oil temperature based on quantum sensing technology, characterized in that, include: The spin initialization of the diamond nitrogen-vacancy color center is achieved by using laser to excite the diamond nitrogen-vacancy color center; While the laser is being applied, a frequency-sweeping microwave is applied to the diamond nitrogen-vacancy center to modulate the spin state of the diamond nitrogen-vacancy center. The fluorescence signal emitted by the diamond nitrogen-vacancy color center under the action of the laser and the swept microwave was detected; A photodetector magnetic resonance curve is generated based on the fluorescence signal, and the photodetector magnetic resonance curve represents the change of fluorescence intensity with microwave frequency; Extract the zero-field splitting value from the optically detected magnetic resonance curve; Based on the extracted zero-field splitting value, the corresponding transformer oil temperature is obtained according to the predetermined functional relationship between the zero-field splitting value and temperature.

2. The method according to claim 1, characterized in that, Extracting the zero-field splitting value from the optically detected magnetic resonance curve includes: The zero-field splitting value is obtained by identifying the point of lowest fluorescence intensity in the optically detected magnetic resonance curve.

3. The method according to claim 1, characterized in that, The predetermined zero-field splitting value and temperature are related by a polynomial fitting model.

4. The method according to claim 3, characterized in that, The polynomial fitting model was obtained through multiple experimental calibrations. The calibration process included measuring the zero-field splitting value at different known temperatures and establishing a mapping relationship.

5. A transformer oil temperature measuring device based on quantum sensing technology, characterized in that, include: Optical path module, microwave module, and data acquisition module; The optical path module includes a laser source and a photodetector. The laser source is used to generate excitation light, and the photodetector is used to receive fluorescence signals. The microwave module includes a microwave source and a microwave antenna. The microwave source is used to generate frequency-sweeping microwaves, and the microwave antenna is used to radiate the frequency-sweeping microwaves. The data acquisition module includes a data acquisition card and a microcomputer system. The data acquisition card is connected to the photodetector, and the microcomputer system is connected to the data acquisition card.

6. The apparatus according to claim 5, characterized in that, The optical path module also includes an optical fiber, which connects the laser source and the photodetector and is used to transmit the excitation light.

7. The apparatus according to claim 5, characterized in that, The optical path module also includes an optical fiber circulator, which is disposed in the optical fiber and is used to enable the excitation light to be transmitted unidirectionally to the diamond nitrogen-vacancy color center.

8. The apparatus according to claim 5, characterized in that, The optical path module also includes a filter, which is disposed in the incident optical path of the photodetector to filter out stray light.

9. The apparatus according to claim 5, characterized in that, The microwave module further includes a power amplifier connected to the microwave source and the microwave antenna, which is used to amplify the power of the swept microwave.

10. The apparatus according to claim 9, characterized in that, The microwave module also includes a circulator, which is disposed between the microwave source and the power amplifier to prevent microwave signal feedback.

11. The apparatus according to claim 5, characterized in that, The microwave antenna is integrated into the probe structure, which is in direct contact with the transformer oil.

12. The apparatus according to claim 11, characterized in that, The probe structure also includes a diamond nitrogen-vacancy color center, which is fixed inside the probe.

13. The apparatus according to claim 5, characterized in that, The excitation light is a green laser with an emission wavelength of 532nm.

14. The apparatus according to claim 5, characterized in that, The microcomputer system is equipped with control software, which is used to control the frequency sweep parameters of the microwave source and display the optical detection magnetic resonance curve in real time.

15. The apparatus according to claim 14, characterized in that, The control software also stores a predetermined functional relationship between the zero-field splitting value and temperature, which is used to automatically calculate the temperature value of the transformer oil.

16. A computer-readable storage medium, characterized in that, It stores a computer program that, when executed in a computer, causes the computer to perform the method described in any one of claims 1-4.

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