Fault arc signal detection method and device based on Rydberg atoms

Abstract

The invention discloses a fault arc signal detection method and device based on Rydberg atoms, belongs to the technical field of power fault detection, and solves the problem of how to improve the responsivity of the Rydberg atoms to fault arc signals under the non-resonance condition. According to the method, an EIT spectral linear model is constructed, the detection light Rabian frequency is adjusted by changing the power of the detection light, so that a spectrogram presents an intermediate state of a conversion process from EIT to EIA, the slope of a fault arc response position on the spectrogram is increased, the responsivity of a Rydberg atomic system to a fault arc electromagnetic signal under a non-resonance condition is improved, and the reliability of the Rydberg atomic system is improved. The performance of a Rydberg atom microwave sensing system is remarkably improved, and the method is applied to detection of fault arc signals in a high-voltage environment and has important significance in reducing personnel injury and property loss risks caused by local discharge faults in various electric power facilities.

Description

Technical Field

[0001] The invention belongs to the technical field of power fault detection, and relates to a fault arc signal detection method and device based on Rydberg atoms. Background Art

[0002] Fault arc is a phenomenon of high-power discharge between conductors, which is common in localized discharge faults of insulation in various power facilities, such as aging of high-voltage transmission cable insulation, single-phase grounding fault in distribution network, internal short circuit of transformer, and fast transient overvoltage (VFTO) in gas-insulated substation (GIS). With the increase of electricity consumption of residents across the country, the frequency of electrical fire accidents has also increased accordingly. Among the electrical fire accidents that occur each year, about 80% of them are related to fault arcs. The detection of fault arcs is related to the safety of life and property of power users and enterprises.

[0003] Existing arc fault detection methods mainly include the following methods: (1) Intrusive detection based on time-frequency domain analysis of voltage and current data and pattern recognition algorithms, such as the literature "Research on the Influence of Different Electrode Materials on DC Arc Fault Detection Characteristics" (Wang J, Meng Y, Li X, Chen S. 2021IEEE 66th Holm Conference on Electrical Contacts (HLM). San Antonio, TX, USA, 2021: 89-94. DOI: 10.1109 / HLM51431.2021.9671187.), which analyzes and compares the differences in arc fault currents based on different materials from the perspective of time domain, discusses the reasons for the differences in arc fault phenomena of different materials, uses wavelet transform method to find out the differences in arc fault detection characteristics, compares from the perspective of time-frequency domain, and summarizes the influence of different materials on DC arc fault detection characteristics. (2) Based on the physical characteristics outside the fault arc circuit system, non-intrusive detection methods are used to analyze the acoustic signals, optical signals, electromagnetic radiation signals, thermal signals, etc. emitted by the fault arc circuit system. For example, the document "ASeries DC Arc Fault Detection Method Based on Steady Pattern of High-Frequency Electromagnetic Radiation" (Zhao S, Wang Y, Niu F, Zhu C, Xu Y, Li K. IEEE Transactions on Plasma Science, 2019, 47(9): 4370-4377. DOI: 10.1109 / TPS.2019.2932747.) uses the electromagnetic radiation (EMR) emitted by the arc as the test basis and calculates patterns such as the structural similarity index (SSIM) and 6 dB bandwidth bins (dB BWBs) to accurately identify arc faults in different DC systems and distinguish arc faults from normal operation.

[0004] Nowadays, most studies on arc fault detection based on arc RF signals use traditional metal antennas to receive RF signals from arc faults, and use the characteristic frequency band of arc RF signals at the MHz level to identify arc faults. However, in environments with extremely high electric field strength, such as detecting electromagnetic signals dissipated from the arc fault of a power transformer in the surrounding free space, the traditional antenna, which inevitably contains metal, will easily cause circuit overload, which in turn causes the traditional arc detector circuit to heat up, short-circuit, or even burn out.

[0005] In recent years, microwave sensing systems based on Rydberg atoms have gradually entered the field of vision of power companies and related research institutes due to their advantages of high sensitivity, high precision, wide working bandwidth, and real-time multi-frequency demodulation and monitoring, becoming one of the research hotspots in the field of quantum precision measurement. Since the probe part of the Rydberg atomic sensing system is completely optical, the metal of the probe part can be completely removed by building a fiber-coupled gas chamber, so that the advantage of non-destructive measurement of the atomic system can still resist interference in an environment with extremely high electric field strength and safely complete the task of detecting electromagnetic signals.

[0006] In fact, cesium atoms are commonly used experimental objects in Rydberg atomic systems. The resonance frequency of adjacent energy levels with relatively low principal quantum numbers (20 to 60) is 1 to 3 orders of magnitude larger than the main frequency of the fault arc signal (below 100 MHz). The energy levels with relatively high principal quantum numbers (above 60) of cesium atoms are difficult to excite with lasers, which results in a small number of atoms being successfully excited. In general, two-photon excitation is rarely considered. Therefore, the Rydberg atomic sensing system can only detect arc signals in a non-resonant manner using the ACStark effect. Compared with the microwave superheterodyne method for detecting electromagnetic signals in a resonant manner, the bandwidth in the non-resonant case is one order of magnitude smaller, the sensitivity is three orders of magnitude smaller, and the overall responsiveness is inferior to that of the resonant method. Therefore, it is particularly important to overcome the problem of low responsiveness of Rydberg atoms to fault arc signals in a non-resonant condition. Summary of the invention

[0007] The technical problem to be solved by the present invention is how to improve the responsiveness of Rydberg atoms to fault arc signals under non-resonance conditions.

[0008] The present invention solves the above technical problems through the following technical solutions:

[0009] The method for detecting arc fault signals based on Rydberg atoms comprises the following steps:

[0010] S1, splitting the laser output by the first laser into a first detection light and a second detection light through a polarization beam splitter cube, the first detection light is incident on the first cesium atomic gas chamber to couple the cesium atom to transition from the ground state to the excited state, and the second detection light is incident on the saturation spectrum optical path to perform wavelength locking;

[0011] S2, using the laser output by the second laser as coupling light, and incident it in the first cesium atomic gas chamber in reverse, so that the coupled cesium atoms transition from the excited state to the Rydberg state, and the gain photoelectric probe scans the detuning amount of the coupling light to generate an EIT spectrum;

[0012] S3, constructing an EIT spectrum linear model based on the first detection light and the coupled light;

[0013] S4, adjusting various parameters of the EIT spectrum linear model to obtain the intermediate state spectrum;

[0014] S5. Loading a fault arc signal to the first cesium atomic gas chamber, obtaining the slope of the fault arc signal response position in the spectrum based on the intermediate state spectrum, and calculating the response amplitude of the fault arc signal.

[0015] Furthermore, the ground state of the cesium atom is 6S 1 / 2 , the excited state is 7P 3 / 2 , the Rydberg state is 31D 5 / 2 .

[0016] Furthermore, the laser wavelength of the first laser is 456 nm, and the laser wavelength of the second laser is 1072 nm.

[0017] Furthermore, S3 comprises the following steps:

[0018] S31, writing the first detection light Rabi frequency, the first detection light detuning amount, the coupling light Rabi frequency and the coupling light detuning amount into a Hamilton matrix, and simplifying the Hamilton matrix;

[0019] S32, writing the dephasing frequency of the excited state of the cesium atom into the dephasing matrix, constructing the optical Bloch equations based on the Hamilton matrix and the dephasing matrix, and calculating the density matrix element of the detection light absorption coefficient;

[0020] S33, solve the relationship between the repolarizability and the density matrix element;

[0021] S34. The linear model expression of EIT spectrum is obtained based on electrodynamics.

[0022] Furthermore, the Hamilton matrix is ​​represented by the following logic in S31:

[0023]

[0024] Where H represents the Hamilton matrix, represents the reduced Planck constant.

[0025] Furthermore, the optical Bloch equations are represented by the following logic in S32:

[0026]

[0027] ρ 11 +ρ 22 +ρ 33 =1

[0028] In the formula, γ 2represents the dephasing frequency of the excited state of the cesium atom, Δ P represents the detuning amount of the first detection light, Δ C Denotes the coupling light detuning amount, Ω P represents the first detection light Rabi frequency, Ω C represents the Rabi frequency of the coupled light, i represents the imaginary unit, ρ xy represents the matrix element of the xth row and yth column of the density matrix ρ, Represents the time derivative of the matrix element, x∈[1,3], y∈[1,3].

[0029] Furthermore, the following logic is used in S33 to solve the relationship between the complex polarizability and the density matrix element:

[0030]

[0031] In the formula, χ 21 Represents the repolarization rate, N a Indicates the number of atoms per unit space in the area where the laser interacts with atoms, μ 21 represents the detection light transition matrix element, ε 0 represents the dielectric constant of vacuum.

[0032] Furthermore, the EIT spectrum linear model expression in S34 is as follows:

[0033]

[0034] Where P represents the transmitted light power of the first detection light, Exp{·} represents exponential operation, and C represents a constant term composed of system parameters and physical constants.

[0035] Furthermore, the response amplitude of the fault arc signal is calculated using the following logic in S5:

[0036] A=κδ

[0037] Where A represents the response amplitude of the fault arc signal, κ is the slope of the fault arc signal response position in the intermediate state spectrum, and δ represents the energy level offset.

[0038] A fault arc signal detection device based on Rydberg atoms, comprising a first laser, a second laser, a polarization beam splitter cube, a first cesium atom gas chamber, a saturation spectrum optical path, a gain photoelectric probe and an arc lighter;

[0039] The laser light output by the first laser is split into a first detection light and a second detection light by the polarization beam splitter cube, the first detection light is incident on the first cesium atom gas chamber to couple the cesium atom to transition from the ground state to the excited state, and the second detection light is incident on the saturation spectrum optical path to perform wavelength locking;

[0040] The laser light output by the second laser is used as coupling light, which is incident on the first cesium atom gas chamber in reverse, and the coupled cesium atom transitions from the excited state to the Rydberg state, and the gain photoelectric probe scans the detuning amount of the coupling light to generate an EIT spectrum;

[0041] The first cesium atomic gas cell is used to construct an EIT spectrum linear model based on the first detection light and the coupled light;

[0042] The gain photoelectric probe is used to adjust various parameters of the EIT spectrum linear model to obtain the intermediate state spectrum;

[0043] The arc lighter is used to load the fault arc signal to the first cesium atomic gas chamber, obtain the slope of the fault arc signal response position in the spectrum based on the intermediate state spectrum, and calculate the response amplitude of the fault arc signal.

[0044] The advantages of the present invention are:

[0045] The present invention adopts a two-photon cascade excitation method to make cesium atoms transition from a ground state to an excited state to a Rydberg state, constructs an EIT spectrum linear model, and adjusts the detection light Rabi frequency by changing the detection light power so that the spectrum shows an intermediate state of the EIT to EIA transition process, increases the slope of the fault arc response position on the spectrum, improves the responsiveness of the Rydberg atomic system to the fault arc electromagnetic signal under non-resonance conditions, significantly improves the performance of the Rydberg atomic microwave sensing system, and is applied to the detection of fault arc signals under high-voltage environments, which is of great significance for reducing the risk of personal injury and property loss caused by local discharge faults in various power facilities. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 is a flow chart of a fault arc signal detection method based on Rydberg atoms according to the first embodiment of the present invention;

[0047] Figure 2 is a schematic diagram of the energy levels of the Rydberg atom excitation path according to the first embodiment of the present invention;

[0048] Figure 3 1 is a spectrum diagram of the EIT, intermediate state and EIA of the first embodiment of the present invention;

[0049] FIG4(a) is a schematic diagram of the detection light transmission spectrum at different detection light Rabi frequencies when no fault arc signal is loaded according to the first embodiment of the present invention;

[0050] FIG4( b ) is a schematic diagram of the response of different detection light Rabi frequencies to a fault arc signal according to the first embodiment of the present invention;

[0051] Figure 5 It is a structural diagram of a fault arc signal detection device based on Rydberg atoms according to the second embodiment of the present invention. DETAILED DESCRIPTION

[0052] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0053] The technical solution of the present invention is further described below in conjunction with the accompanying drawings and specific embodiments:

[0054] Embodiment 1

[0055] like Figure 1-2 Specifically, a fault arc signal detection method based on Rydberg atoms is disclosed, comprising the following steps:

[0056] S1, splitting the laser output by the first laser into a first detection light and a second detection light through a polarization beam splitter cube, the first detection light is incident on the first cesium atomic gas chamber to couple the cesium atom to transition from the ground state to the excited state, and the second detection light is incident on the saturation spectrum optical path to perform wavelength locking;

[0057] S2, using the laser output by the second laser as coupling light, and incident it in the first cesium atomic gas chamber in reverse, so that the coupled cesium atoms transition from the excited state to the Rydberg state, and the gain photoelectric probe scans the detuning amount of the coupling light to generate an EIT spectrum;

[0058] Furthermore, the ground state of the cesium atom is 6S 1 / 2 , the excited state is 7P 3 / 2 , the Rydberg state is 31D 5 / 2 .

[0059] Furthermore, the laser wavelength of the first laser is 456 nm, and the laser output by the first laser is used as a probe light to couple the cesium atoms from the ground state 6S 1 / 2 Transition to excited state 7P 3 / 2 , make the first level transition.

[0060] In this embodiment, the detection light is divided into two detection lights by the polarization beam splitter cube. The first detection light is incident on the first cesium atom gas chamber. The first detection light passes through the first cesium atom gas chamber and enters the gain photoelectric probe to read the transmittance information of the first detection light through the first cesium atom gas chamber. The first detection light will interact with the cesium atom when passing through the first cesium atom gas chamber. The gain photoelectric probe is used to read the intensity and spectrum of the transmitted light, which can provide relevant information about the cesium atom transition and energy level structure. The second detection light is incident on the saturated spectrum optical path for wavelength locking. The saturated spectrum optical path has the characteristics of saturated absorption, so that the detection light matches the energy level of the cesium atom transition from the ground state to the excited state, and the detection light is accurately locked at the resonance frequency of the cesium atom transition from the ground state to the excited state, thereby improving the detection accuracy and sensitivity.

[0061] Furthermore, the laser wavelength of the second laser is 1072 nm, and the laser output by the second laser is used as coupling light to couple the cesium atom from the excited state 7P 3 / 2 Transition to Rydberg state 31D 5 / 2 , and make the second level transition.

[0062] In this embodiment, the coupling light is incident on the first cesium atomic gas chamber in the opposite direction of the detection light incident on the first cesium atomic gas chamber, and the coupling light and the first detection light work together to produce the EIT effect. C , the formation of the electromagnetically induced transparent window can be precisely controlled to produce the EIT spectrum.

[0063] Furthermore, the first detection light Rabi frequency Ω P ~1MHz, the coupled light Rabi frequency Ω C =10.9MHz, indicating that the intensity of the coupled light is much greater than that of the detection light, satisfying the condition of weak detection light and strong coupling light, further ensuring that the coupled light dominates the EIT effect, and the transmittance change of the first detection light is caused by the detuning amount of the coupled light.

[0064] Furthermore, since the cesium atom is converted from the ground state 6S 1 / 2 To the excited state 7P 3 / 2 The two energy level transition dipole moments are small and meet the weak detection light intensity coupling light condition, and the first level transition probability is low. In this embodiment, the cesium atomic gas chamber is heated to 400K and the first detection light transmission spectrum signal intensity is improved by increasing the atomic vapor density.

[0065] In this embodiment, the EIT effect (Electromagnetically Induced Transparency) is a quantum interference effect. This embodiment adopts a two-photon cascade excitation method. Through the synergistic effect of the first detection light and the coupling light, the cesium atom is transitioned from the ground state to the excited state via the Rydberg state. The first detection light, with the help of the coupling light, makes the atom enter a coherent energy level structure to form an electromagnetically induced transparent window. The transmittance information of the first detection light passing through the first cesium atom gas chamber is read by the gain photoelectric probe, which effectively enhances the signal intensity of the cesium atom excitation and provides high-precision EIT spectrum measurement.

[0066] S3, constructing an EIT spectrum linear model based on the first detection light and the coupled light;

[0067] In this embodiment, S3 includes the following steps:

[0068] S31, writing the first detection light Rabi frequency, the first detection light detuning amount, the coupling light Rabi frequency and the coupling light detuning amount into a Hamilton matrix, and simplifying the Hamilton matrix;

[0069] In this embodiment, the first detection light is pulled closer to the frequency Ω P , the first detection light detuning amount Δ P 、Coupled light Rabi frequency Ω C And the coupling light detuning amount Δ C The non-diagonal terms of the Hamilton matrix are written, and the Hamilton matrix is ​​subjected to unitary transformation and cycloid approximation to eliminate the time-dependent factors in the Hamilton matrix. In this embodiment, the Hamilton matrix is ​​represented by the following logic:

[0070]

[0071] Where H represents the Hamilton matrix, represents the reduced Planck constant.

[0072] S32, writing the dephasing frequency of the excited state of the cesium atom into the dephasing matrix, constructing the optical Bloch equations based on the Hamilton matrix and the dephasing matrix, and calculating the density matrix element of the detection light absorption coefficient;

[0073] In this embodiment, since the spontaneous emission frequency of the Rydberg state of the cesium atom is much lower than the spontaneous emission frequency of the excited state, this embodiment only considers the dephasing frequency γ of the excited state of the cesium atom. 2 And write the dephasing matrix, and build the optical Bloch equations based on the Hamilton matrix and the dephasing matrix. This embodiment uses the following logic to represent the optical Bloch equations:

[0074]

[0075] ρ 11 +ρ 22 +ρ 33 =1

[0076] In the formula, γ 2 represents the dephasing frequency of the excited state of the cesium atom, Δ P represents the detuning amount of the first detection light, Δ C Denotes the coupling light detuning amount, Ω P represents the first detection light Rabi frequency, Ω C represents the Rabi frequency of the coupled light, i represents the imaginary unit, ρ xy represents the matrix element of the xth row and yth column of the density matrix ρ, Represents the time derivative of the matrix element, x∈[1,3], y∈[1,3].

[0077] In this embodiment, a dephasing matrix is ​​used to represent the non-Hermitian part of the density matrix evolution equation of the Rydberg atom microwave sensing system. In this embodiment, an optical Bloch equation group is constructed as the density matrix evolution equation, and the dephasing matrix is ​​used to represent the irreversible time evolution caused by factors such as spontaneous radiation, collision and transition. By adjusting the parameters in the dephasing matrix, the quantum system behavior under different environments is simulated, the experimental conditions are changed and the experimental results are optimized.

[0078] The construction of the optical Bloch equations can describe the dynamic behavior of the two energy levels of the cesium atom under the interaction with the detection light field and the coupling light field. In this embodiment, by solving the optical Bloch equations under the steady-state approximation, the density matrix element ρ of the corresponding first detection light absorption coefficient can be obtained. 21 .

[0079] S33, solve the relationship between the repolarizability and the density matrix element;

[0080] The complex polarization intensity is a complex representation of the electric dipole moment, which can capture the polarization behavior of cesium atoms in the medium under the action of an external electromagnetic field. When the probe light and the coupled light field irradiate the cesium atoms, the particles generate an induced electric dipole moment driven by the light field, and the complex polarization intensity directly characterizes this induced polarization phenomenon.

[0081] In this embodiment, according to the definition of repolarization intensity And the repolarization intensity and the first detection light Rabi frequency Ω P Relationship Use the following logic to solve the relationship between the complex polarizability and the density matrix element:

[0082]

[0083] In the formula, χ 21 Represents the repolarization rate, N a Indicates the number of atoms per unit space in the area where the laser interacts with atoms, μ 21 represents the detection light transition matrix element, ε 0 represents the dielectric constant of vacuum.

[0084] S34, based on electrodynamics, the linear model expression of EIT spectrum is obtained;

[0085] In this embodiment, based on the known electrodynamics, the approximate relationship between the power of the first detection light before and after passing through the cesium atom gas cell is: Among them, k P represents the first detection light wave number, L represents the length of the interaction between the cesium atom and the laser in the cesium atom gas chamber, and P 0 Represents the initial optical power of the incident light. Based on the above relationship, this embodiment ignores the Doppler average effect and obtains the expression of the EIT spectrum linear model:

[0086]

[0087] Where P represents the transmitted light power of the first detection light, Exp{·} represents exponential operation, and C represents a constant term composed of system parameters and physical constants. In this embodiment, C=1 is taken to simplify the theoretical model.

[0088] According to the above expression, the EIT spectrum line shape is related to the first detection light detuning amount Δ P 、The first detection light Rabi frequency Ω P 、Coupled light Rabi frequency Ω C and the excited state dephasing frequency γ 2 Related.

[0089] S4, adjusting various parameters of the EIT spectrum linear model to obtain the intermediate state spectrum;

[0090] In this embodiment, the first detection light detuning amount Δ P 、Coupled light Rabi frequency Ω C and the excited state dephasing frequency γ 2 , the EIT spectrum is transformed into the EIA spectrum. When the amplitudes of the transmission peak and the absorption peak in the spectrum are basically the same and the maximum slope of the spectrum line reaches a maximum value, it is recorded as an intermediate state and the intermediate state spectrum is obtained.

[0091] In this embodiment, the various parameters of the EIT spectrum linear model are adjusted. When the first detection light detuning amount Δ P = 0MHz, the obtained detection light transmission spectrum shows a relationship with the coupling light detuning amount Δ C=0MHz position symmetrical EIT peak; however, this embodiment converts cesium atoms from 6S 1 / 2 →7P 3 / 2 When the first detection light is frequency-locked by the transition saturation spectrum, the Rabi frequency of the first detection light is simply locked in the Doppler absorption background by PID control for 6S 1 / 2 ,F=3→7P 3 / 2 , near the transition frequency of the hyperfine structure energy level of F=4.

[0092] When cesium atoms are excited in the cesium atomic gas chamber, it is difficult to avoid the situation where the detuning amount of the first detection light is not zero due to environmental interference and PID parameter settings. In addition, under the external heating of the cesium atomic gas chamber, some atoms still transition to other hyperfine energy levels of the intermediate state, and some of them participate in causing the detuning amount of the detection light to be not zero. In this embodiment, the detuning amount of the first detection light Δ P After setting it to non-zero, the detection light transmission spectrum is no longer symmetrical. P After gradually increasing, the absorption peak amplitude gradually increases, and finally exceeds the transmission peak amplitude to become the main feature of the detection light transmission spectrum, that is, it changes from EIT to EIA. In the process of EIT changing to EIA, there is a state where the transmission peak and the absorption peak amplitude are equivalent, which is recorded as the intermediate state. The slope of the detection light transmission spectrum corresponding to the intermediate state is much higher than that of the detection light transmission spectrum corresponding to EIT and EIA, which can effectively improve the detection performance of non-resonant detection of fault arc signals based on the ACStark effect.

[0093] In fact, the condition for inducing the transition from EIT to EIA is not only determined by adjusting the first detection light detuning amount Δ P By adjusting the coupling light Rabi frequency Ω C and the excited state dephasing frequency γ 2 The process of transformation from EIT to EIA can also be achieved.

[0094] like Figure 3 As shown, in this embodiment, the first detection light detuning amount Δ P =2MHz, coupled light Rabi frequency Ω C =10MHz, excited state dephasing frequency γ 2 =2MHz, detection light Rabi frequencyΩ P From left to right, they are 8MHz, 1.8MHz, and 0.4MHz, corresponding to EIT, intermediate state, and EIA spectra, respectively.

[0095] S5, loading the first cesium atomic gas chamber with a fault arc signal, obtaining the slope of the fault arc signal response position in the spectrum based on the intermediate state spectrum, and calculating the response amplitude of the fault arc signal;

[0096] In this embodiment, the response amplitude of the fault arc signal is calculated using the following logic:

[0097] A=κδ

[0098] Where A represents the response amplitude of the fault arc signal, κ is the slope of the fault arc signal response position in the intermediate state spectrum, and δ represents the energy level offset.

[0099] The existing technology is based on the non-resonant detection method, relying on the energy level shift of the atomic energy level under the ACStark effect related to the electric field strength E(t) of the external electromagnetic wave. Among them, α represents the electrical susceptibility of the entire atomic vapor, which is related to the atomic principal quantum number n by α~n 7 , the high principal quantum number n of the Rydberg atom can ensure that the detection of the fault arc signal based on the non-resonance detection method has a high detection response. When the amplitude of E(t) is smaller than the EIT peak width, it can be approximately considered that the response amplitude of the fault arc signal sensed in the detection light transmission spectrum is A. By adjusting the detuning amount Δ of the first detection light P 、Coupled light Rabi frequency Ω C and the excited state dephasing frequency γ 2 , adjust the atoms to the intermediate state with a very large slope, and improve the responsiveness of the Rydberg atom microwave sensing system to fault arc signals.

[0100] In this embodiment, a commercial dual-arc pulse lighter is used to simulate the fault arc in an actual power instrument. After the fault arc signal is loaded into the cesium atomic gas chamber, it can be observed that the modulation oscillation caused by the time-varying characteristics of the fault arc signal appears in the signal peak of the detection light transmission spectrum. The oscillation wave packet usually has a maximum value at the center of the spectrum signal, resulting in that under the EIT and EIA spectra of traditional technologies, the fault arc signal usually takes a response maximum at the peak with a smaller slope, while in the intermediate state spectrum, the sweep width can be set to zero at the coupling light detuning point with the largest slope in the intermediate state spectrum, thereby obtaining a relatively higher response.

[0101] like Figure 4(a) to 4(b) As shown, the detection light Rabi frequency Ω P From the left to the right, they are 2.5 MHz, 0.9 MHz, and 0.5 MHz. In the specific implementation of this embodiment, the coupling light power is set to 280 mW, corresponding to the theoretical coupling light Rabi frequency Ω C =10.9MHz, in this example, the detection light power of the first cesium atomic gas chamber is changed by adjusting the filter, thereby adjusting the first detection light Rabi frequency Ω P , when the detection laser power is 970μW, 133μW and 46μW respectively, the corresponding first detection light Rabi frequency Ω PThe values ​​are 2.5 MHz, 0.9 MHz and 0.5 MHz respectively, and the EIT, intermediate state and EIA spectra of the EIT spectrum linear model are obtained as shown in Figure 4(a).

[0102] When Ω P =2.5MHz, the EIT spectrum signal is in a transmission state, and the actual EIT transmission peak is asymmetric. Due to the increase in the detection light power, the EIT transmission peak is power broadened, resulting in the overall line width being significantly larger than that of other spectra.

[0103] When Ω P =0.9MHz, the spectrum signal presents an intermediate state, and the slope between the signal center and the non-resonant fault arc response position is significantly larger than that in other cases;

[0104] When Ω P When =0.5MHz, the EIA spectrum signal shows an absorption state, and three sharp absorption peaks appear in the spectrum.

[0105] Depend on Figure 4(a) to 4(b) It can be seen that the fault arc spectrum signal output under the EIT and EIA spectra decays rapidly with the increase of frequency, and is buried in the noise floor at 827kHz and 702kHz respectively, while the output signal of the intermediate state responds to the stronger of the two sets of electromagnetic signals generated by the double arc pulse lighter until 1.5MHz, and the signal-to-noise ratio remains above 10dBm; for the peak at about 32.5kHz with the highest intensity in the fault arc signal, the signal-to-noise ratios of the three spectra are 30dBm, 46dBm, and 38.2dBm respectively, and the signal-to-noise ratio of the intermediate state spectrum is 46dBm, which is at least 7.8dBm higher in the power sensitivity of the fault arc signal than the other two states.

[0106] Embodiment 2

[0107] like Figure 5 As shown, the present invention also discloses a fault arc signal detection device based on Rydberg atoms, comprising a first laser 11, a second laser 12, a polarization beam splitter cube 21, a first cesium atomic gas chamber 31, a saturation spectrum optical path, a gain photoelectric probe 41 and an arc lighter 51;

[0108] The laser light outputted by the first laser 11 is divided into a first detection light and a second detection light by the polarization beam splitter cube 21. The first detection light is incident on the first cesium atom gas chamber 31 to couple the cesium atom to transition from the ground state to the excited state. The second detection light is incident on the saturation spectrum optical path to perform wavelength locking.

[0109] The laser light outputted by the second laser 12 is used as coupling light, which is incident on the first cesium atom gas chamber 31 in reverse, and the coupled cesium atom transitions from the excited state to the Rydberg state. The gain photoelectric probe 41 scans the detuning amount of the coupling light to generate an EIT spectrum.

[0110] The first cesium atomic gas chamber 31 is used to construct an EIT spectrum linear model based on the first detection light and the coupled light;

[0111] The gain photoelectric probe 41 is used to adjust various parameters of the EIT spectrum linear model to obtain the intermediate state spectrum;

[0112] The arc lighter 51 is used to load the fault arc signal to the first cesium atomic gas chamber 31, obtain the slope of the fault arc signal response position in the spectrum based on the intermediate state spectrum, and calculate the response amplitude of the fault arc signal.

[0113] Furthermore, the ground state of the cesium atom is 6S 1 / 2 , the excited state is 7P 3 / 2 , the Rydberg state is 31D 5 / 2 .

[0114] Furthermore, the laser wavelength of the first laser 11 is 456 nm, and the laser wavelength of the second laser 12 is 1072 nm.

[0115] Furthermore, the arc lighter 51 is a commercial double arc pulse lighter, which is used to simulate the fault arc in the actual power instrument.

[0116] Furthermore, it also includes a first half-wave plate 61, a filter 71, a first lens 81, and a first dichroic mirror 91; the first laser 11 passes through the first half-wave plate 61 and the polarization beam splitter cube 21 to output a first detection light, and the first detection light passes through the filter 71, the first lens 81, and the first dichroic mirror 91 once, and is incident on the first cesium atomic gas chamber 31, coupling the cesium atom to transition from the ground state to the excited state.

[0117] Furthermore, the saturation spectrum optical path includes a double-sided reflector 96, a second cesium atomic gas chamber 32, a third half-wave plate 63, a first PBS22, a second reflector 94, a third reflector 95 and a balanced photoelectric probe 42; the second detection light is reflected in the direction of the second cesium atomic gas chamber 32 and the second reflector 94 respectively through the double-sided reflector 96, and the second detection light reflected in the direction of the second cesium atomic gas chamber 32 passes through the third half-wave plate 63 and the first PBS22 in sequence, and is incident on the balanced photoelectric probe 42; the second detection light reflected in the direction of the second reflector 94 passes through the third reflector 95 and the first PBS22 in sequence, and is divided into two laser beams by the first PBS22, and is incident on the balanced photoelectric probe 42 and the third half-wave plate 63 respectively. The laser incident on the third half-wave plate 63 passes through the second cesium atomic gas chamber 32 and is incident on the double-sided reflector 96, so that the wavelength of the second detection light is locked in the saturation spectrum optical path.

[0118] Furthermore, it also includes a second half-wave plate 62, a second PBS23, a second lens 82, a first reflector 93, a second dichroic mirror 92 and a third lens 83; the laser output by the second laser 12 is used as coupling light, which passes through the second half-wave plate 62 and the second PBS23 in sequence, and the second PBS23 divides the coupling light into two beams, one beam is incident on the wavelength meter for monitoring the actual wavelength of the coupling light, and the other beam passes through the second lens 82, the first reflector 93 and the second dichroic mirror 92 in sequence and then is reversely incident on the first cesium atomic gas chamber 31, and the coupled cesium atoms transition from the excited state to the Rydberg state. The coupling light passes through the first cesium atomic gas chamber 31 and is combined with the first detection light through the first dichroic mirror 91 and then is incident on the light collecting tube. The second dichroic mirror 92 combines the first detection light and the coupling light and then passes through the third lens 83 to be incident on the gain photoelectric probe 41.

[0119] like Figure 5 As shown in the figure, HWP represents a half-wave plate, and the first half-wave plate 61, the second half-wave plate 62, and the third half-wave plate 63 are all used to change the polarization direction of the laser, and cooperate with PBS to adjust the light intensity distribution; PBS represents a polarization beam splitter cube, and the polarization beam splitter cube 21, the first PBS22, and the second PBS23 are all used to separate or merge light beams according to polarization states; DM represents a dichroic mirror, and the first dichroic mirror 91 and the second dichroic mirror 92 are all used to separate or merge light beams according to wavelengths; PDA represents a gain photoelectric probe 41, which is used to convert optical signals into amplified electrical signals; PDB represents a balanced photoelectric probe 42, which is used to detect signal differences and suppress noise; the first lens 81, the second lens 82, and the third lens 83 are all used to focus the laser to an intensity sufficient to excite atomic transitions; the filter 71 is used to change the detection light power of the first cesium atomic gas chamber 31, thereby adjusting the first detection light Rabi frequency.

[0120] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A fault arc signal detection method based on Rydberg atoms, characterized in that: The following steps are involved: S1, splitting the laser output by the first laser into a first detection light and a second detection light through a polarization beam splitter cube, the first detection light is incident on the first cesium atomic gas chamber to couple the cesium atom to transition from the ground state to the excited state, and the second detection light is incident on the saturation spectrum optical path to perform wavelength locking; S2, using the laser output by the second laser as coupling light, and incident it in the first cesium atomic gas chamber in reverse, so that the coupled cesium atoms transition from the excited state to the Rydberg state, and the gain photoelectric probe scans the detuning amount of the coupling light to generate an EIT spectrum; S3, constructing an EIT spectrum linear model based on the first detection light and the coupled light; S4, adjusting various parameters of the EIT spectrum linear model to obtain the intermediate state spectrum; S5. Loading a fault arc signal to the first cesium atomic gas chamber, obtaining the slope of the fault arc signal response position in the spectrum based on the intermediate state spectrum, and calculating the response amplitude of the fault arc signal.

2. The fault arc signal detection method based on Rydberg atoms according to claim 1, characterized in that: The ground state of the cesium atom is 6S 1 / 2 , the excited state is 7P 3 / 2 , the Rydberg state is 31D 5 / 2 .

3. The fault arc signal detection method based on Rydberg atoms according to claim 1, characterized in that: The laser wavelength of the first laser is 456 nm, and the laser wavelength of the second laser is 1072 nm.

4. The fault arc signal detection method based on Rydberg atoms according to claim 1, characterized in that: The S3 comprises the following steps: S31, writing the first detection light Rabi frequency, the first detection light detuning amount, the coupling light Rabi frequency and the coupling light detuning amount into a Hamilton matrix, and simplifying the Hamilton matrix; S32, writing the dephasing frequency of the excited state of the cesium atom into the dephasing matrix, constructing the optical Bloch equations based on the Hamilton matrix and the dephasing matrix, and calculating the density matrix element of the detection light absorption coefficient; S33, solve the relationship between the repolarizability and the density matrix element; S34. The linear model expression of EIT spectrum is obtained based on electrodynamics.

5. The fault arc signal detection method based on Rydberg atoms according to claim 4, characterized in that: The Hamilton matrix is ​​represented by the following logic in S31: Where H represents the Hamilton matrix, represents the reduced Planck constant.

6. The fault arc signal detection method based on Rydberg atoms according to claim 5, characterized in that: The optical Bloch equations are represented by the following logic in S32: r 11 +r 22 +r 33 =1 Where γ2 represents the dephasing frequency of the excited state of the cesium atom, Δ P represents the detuning amount of the first detection light, Δ C Denotes the coupling light detuning amount, Ω P represents the first detection light Rabi frequency, Ω C represents the Rabi frequency of the coupled light, i represents the imaginary unit, ρ xy represents the matrix element of the xth row and yth column of the density matrix ρ, Represents the time derivative of the matrix element, x∈[1,3], y∈[1,3].

7. The fault arc signal detection method based on Rydberg atoms according to claim 6, characterized in that: In S33, the relationship between the complex polarizability and the density matrix element is solved using the following logic: In the formula, χ 21 Represents the repolarization rate, N a Indicates the number of atoms per unit space in the area where the laser interacts with atoms, μ 21 represents the detection light transition matrix element, and ε0 represents the vacuum dielectric constant.

8. The fault arc signal detection method based on Rydberg atoms according to claim 7, characterized in that: The linear model expression of EIT spectrum in S34 is as follows: Where P represents the transmitted light power of the first detection light, Exp{·} represents exponential operation, and C represents a constant term composed of system parameters and physical constants.

9. The method for detecting arc fault signals based on Rydberg atoms according to claim 8, characterized in that: The response amplitude of the fault arc signal is calculated using the following logic in S5: A=κδ Where A represents the response amplitude of the fault arc signal, κ is the slope of the fault arc signal response position in the intermediate state spectrum, and δ represents the energy level offset.

10. The fault arc signal detection device based on Rydberg atoms is characterized in that: It includes a first laser, a second laser, a polarization beam splitter cube, a first cesium atomic gas chamber, a saturation spectrum optical path, a gain photoelectric probe and an arc lighter; The laser light output by the first laser is split into a first detection light and a second detection light by the polarization beam splitter cube, the first detection light is incident on the first cesium atom gas chamber to couple the cesium atom to transition from the ground state to the excited state, and the second detection light is incident on the saturation spectrum optical path to perform wavelength locking; The laser light output by the second laser is used as coupling light, which is incident on the first cesium atom gas chamber in reverse, and the coupled cesium atom transitions from the excited state to the Rydberg state, and the gain photoelectric probe scans the detuning amount of the coupling light to generate an EIT spectrum; The first cesium atomic gas cell is used to construct an EIT spectrum linear model based on the first detection light and the coupled light; The gain photoelectric probe is used to adjust various parameters of the EIT spectrum linear model to obtain the intermediate state spectrum; The arc lighter is used to load the fault arc signal to the first cesium atomic gas chamber, obtain the slope of the fault arc signal response position in the spectrum based on the intermediate state spectrum, and calculate the response amplitude of the fault arc signal.

Images