Non-contact residual current detection method and device based on cross-shaped magnetic sensor array

Abstract

The application discloses a non-contact residual current detection method and device based on a cross-shaped magnetic sensor array. The method constructs a five-point cross-shaped magnetoresistance sensor array which is central symmetric, and uses the sensors on the secondary distribution axis to obtain the magnetic field gradient information in the orthogonal direction; a nonlinear magnetic field inversion model containing the spatial position of the double-core conductor and the residual current is established, and a physical feasible region constraint condition based on engineering specifications is introduced; and a global optimization algorithm is used to solve the residual current and the spatial position of the target double-core conductor. The application solves the problem of poor numerical stability of the traditional linear array inversion equation from the physical layer through array topology optimization, and realizes accurate detection of the weak residual current in the case that the position of the conductor is unknown.

Description

Technical Field

[0001] This invention relates to the field of electrical safety monitoring and measurement technology in power systems, and in particular to a non-contact residual current detection method and device based on a cross-shaped magnetic sensor array suitable for operating conditions where the location of the line is unknown. Background Technology

[0002] Modern building electrical wiring commonly uses concealed wiring, often employing dual-core or multi-core parallel structures. While this satisfies aesthetic requirements, the wires hidden within walls make troubleshooting residual current faults extremely difficult. Traditional contact-based detection often requires damaging the wall or tracing from the end point, resulting in high repair costs and low efficiency. Therefore, non-contact measurement technology based on magnetic field induction has become a research hotspot. Early solutions often used ring or closed magnetic sensor arrays, which, while offering high measurement accuracy, require the sensor to spatially surround the conductor being measured, making them unsuitable for planar measurements on a single side of a wall.

[0003] Currently, to meet the requirements of planar operation, one-dimensional linearly arranged magnetic sensor arrays are widely used in non-contact measurement, often in conjunction with various evolutionary algorithms for parameter inversion. However, this approach has significant technical limitations when facing scenarios where the conductor position is unknown and the operating conditions are complex. Because the linear array is distributed only along a single axis, it lacks effective perception of magnetic field gradient information in orthogonal directions. This leads to a linear correlation between the sensitivity vectors related to position parameters in the inversion equations, causing a surge in the condition number of the observation matrix and resulting in numerical instability in the parameter inversion process. Under these conditions, the system is extremely sensitive to environmental noise and sensor noise floor; even minor signal disturbances can cause the solution results to diverge. Therefore, existing linear array schemes that rely solely on algorithm optimization and cannot complete information from the physical topology are insufficient for achieving high-precision detection of weak residual currents. Summary of the Invention

[0004] This invention provides a non-contact residual current detection method and device based on a cross-shaped magnetic sensor array. Its purpose is to solve the problem of poor numerical stability of existing linear array inversion equations without damaging the wall and with unknown wire positions, and to achieve high-precision detection of weak residual current.

[0005] To achieve the above objectives, the present invention provides a non-contact residual current detection method based on a cross-shaped magnetic sensor array, comprising:

[0006] Step 1: Construct a three-dimensional rectangular coordinate system on the target wall on which the target dual-core wire is laid. The z-axis of the three-dimensional rectangular coordinate system is perpendicular to the target wall and points outward. Construct a centrally symmetrical cross-shaped magnetoresistive sensor array. The x-axis of the three-dimensional rectangular coordinate system is used as the main distribution axis and the y-axis is used as the secondary distribution axis. Magnetoresistive sensors are arranged on the main distribution axis and the secondary distribution axis respectively. The sensitive direction of all magnetoresistive sensors is parallel to the x-axis, so as to use the sensors on the secondary distribution axis to capture magnetic field gradient information.

[0007] Step 2: Based on the cross-shaped magnetoresistive sensor array, the voltage signals output by each magnetoresistive sensor are collected synchronously, and the voltage signals are converted into the corresponding magnetic induction intensity x component test values ​​at each measuring point according to the preset sensor voltage-magnetic field sensitivity coefficient.

[0008] Step 3: Establish a nonlinear magnetic field forward model describing the mapping relationship between the magnetic induction intensity and the parameters of the target two-core conductor; the parameters include live wire current, neutral wire current, concealed depth, y-axis deflection angle, and horizontal offset; wherein, the y-axis deflection angle is defined as the angle between the target two-core conductor and the y-axis of the three-dimensional rectangular coordinate system, and the horizontal offset is defined as the distance from the projection center of the target two-core conductor on the x-axis to the origin of the coordinate system;

[0009] Step 4: Construct an inversion objective function, with the optimization objective being to minimize the sum of squared residuals between the measured values ​​of the magnetic induction intensity x-component and the theoretically calculated values ​​obtained based on the forward model; at the same time, according to the actual concealed wiring engineering specifications, set the physical feasible domain constraints for the concealed wiring depth, y-axis deflection angle, and horizontal offset.

[0010] Step 5: Input the objective function and the physical feasible region constraints into the global optimization algorithm, and perform iterative solution within the solution space defined by the physical feasible region constraints. When the objective function converges, output the optimal solution, thereby obtaining the residual current and spatial location parameters of the target double-core conductor.

[0011] Furthermore, all five magnetoresistive sensors are TMR linear magnetic field sensors, and the third magnetoresistive sensor is located at the origin of the three-dimensional rectangular coordinate system; wherein, the second and fourth magnetoresistive sensors located on the main sensing axis maintain a distance of d1 from the third magnetoresistive sensor, and the first and fifth magnetoresistive sensors located on the secondary sensing axis maintain a distance of d2 from the third magnetoresistive sensor.

[0012] Furthermore, the magnetic induction intensity x component B xi The expression is:

[0013]

[0014] Among them, B xi Let represent the x-component of magnetic flux density measured by the i-th magnetoresistive sensor; i represents the number of the magnetoresistive sensor (i=1,2,3,4,5); μ0 represents the permeability in vacuum; I1 represents the live wire current; I2 represents the neutral wire current; h represents the caching depth; β represents the angle between the current-carrying conductor and the y-axis; r 1i r represents the distance from the i-th magnetoresistive sensor to the live wire I1; 2i This represents the distance from the i-th magnetoresistive sensor to the zero line I2.

[0015] The non-contact residual current detection method based on a cross-shaped magnetic sensor array according to claim 3 is characterized in that the distance r between the magnetoresistive sensor array and the live wire is... 1i This includes the distance between each magnetoresistive sensor and the live wire, calculated using the following expression:

[0016]

[0017]

[0018]

[0019]

[0020]

[0021] The distance r between the magnetoresistive sensing array and the zero line 2i This includes the distance between each magnetoresistive sensor and the zero line, calculated using the following expression:

[0022]

[0023]

[0024]

[0025]

[0026]

[0027] Where D represents the horizontal offset, R represents the half-spacing of the geometric center of the cross-section of the dual-core conductor, and d1 and d2 represent the spacing between the sensors on the main distribution axis x-axis and the secondary distribution axis y-axis, respectively, relative to the center sensor.

[0028] Furthermore, step 3 includes:

[0029] Construct an objective function: The optimization objective is to minimize the sum of squared residuals between the measured values ​​of the magnetic induction intensity x-component and the calculated values ​​based on the mathematical model.

[0030] Set physical feasible region constraints: Based on the engineering specifications of actual concealed lines, preset the effective value range of the concealed depth h, horizontal offset D, and y-axis deflection angle β; input the mathematical model, combined with the physical feasible region constraints and the test value of the magnetic induction intensity x component, into the differential evolution algorithm.

[0031] Furthermore, the mathematical model is specified as follows:

[0032]

[0033]

[0034]

[0035]

[0036]

[0037] The present invention also provides a non-contact residual current detection device based on a cross-shaped magnetic sensor array, comprising:

[0038] The module is used to construct a three-dimensional rectangular coordinate system on the target wall on which the target double-core wire is laid. The x-axis of the three-dimensional rectangular coordinate system is used as the main distribution axis and the y-axis is used as the secondary distribution axis. Five magnetoresistive sensors are arranged on the main distribution axis and the secondary distribution axis to construct a centrally symmetrical cross-shaped magnetoresistive sensor array. The sensitive directions of the five magnetoresistive sensors are all parallel to the x-axis.

[0039] The acquisition module is used to acquire the magnetic induction intensity of the target dual-core wire at each magnetoresistive sensor as the magnetic induction intensity x component test value based on the voltage output of each magnetoresistive sensor in the cross-shaped magnetoresistive sensing array and according to the preset voltage-magnetic field sensitivity coefficient.

[0040] A module is established to create a nonlinear magnetic field forward model describing the mapping relationship between the magnetic induction intensity and the parameters of the target two-core conductor. The parameters include live wire current, neutral wire current, concealed depth, y-axis deflection angle, and horizontal offset. The y-axis deflection angle is defined as the angle between the target two-core conductor and the y-axis of the three-dimensional rectangular coordinate system, and the horizontal offset is defined as the distance from the projection center of the target two-core conductor on the x-axis to the origin of the coordinate system.

[0041] The construction module is used to construct the inversion objective function, with the optimization objective being to minimize the sum of squared residuals between the measured values ​​of the magnetic induction intensity x-component and the theoretical calculation values ​​obtained based on the forward model; at the same time, according to the actual concealed line engineering specifications, the physical feasible domain constraints of the concealed depth, y-axis deflection angle and horizontal offset are set.

[0042] The calculation module is used to input the objective function and the physical feasible region constraints into the global optimization algorithm, perform iterative solution within the solution space defined by the physical feasible region constraints, and output the optimal solution when the objective function converges, thereby obtaining the residual current and spatial location parameters of the target double-core conductor.

[0043] The above-described solution of the present invention has the following beneficial effects:

[0044] This invention constructs a centrally symmetric cross-shaped magnetoresistive sensor array and introduces a secondary distributed axis sensor on the basis of the main distributed axis. By utilizing the orthogonal magnetic field gradient information sensed by the sensor, it effectively eliminates the linear correlation of parameters in the inversion equation system of traditional linear arrays, reduces the condition number of the observation matrix, and solves the technical problem of numerical instability of the inversion equation when the position of the conductor is unknown, which leads to solution divergence or getting trapped in local extrema. From the physical topology level, it solves the technical problem of numerical instability of the inversion equation when the position of the conductor is unknown, which leads to solution divergence or getting trapped in local extrema.

[0045] Furthermore, this invention introduces a physical feasible region constraint based on engineering specifications into the inversion algorithm, which restricts the mathematical solution space to the actual physical existence range, effectively eliminating mathematically valid but physically meaningless solutions, and providing an efficient, economical and stable engineering solution for leakage detection and fault location of concealed circuits.

[0046] Other beneficial effects of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0047] Figure 1 A flowchart illustrating the overall process architecture of a non-contact residual current detection method provided in an embodiment of the invention.

[0048] Figure 2 This is a front view (xz plane projection) of the cross-shaped magnetoresistive sensing array in an embodiment of the present invention.

[0049] Figure 3 This is a top view (xy plane projection) of the cross-shaped magnetoresistive sensing array in an embodiment of the present invention.

[0050] Figure 4 This is a schematic diagram illustrating the spatial geometric relationship between the sensor and the dual-core wire in an embodiment of the present invention;

[0051] Figure 5 This is a functional module structure diagram of the non-contact residual current detection device provided in an embodiment of the present invention;

[0052] Figure 6 A schematic diagram of the hardware structure of a terminal device provided in an embodiment of the present invention. Detailed Implementation

[0053] To make the technical problems, solutions, and advantages of this invention clearer, a detailed description will be provided below with reference to the accompanying drawings and specific embodiments. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0054] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0055] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a locking connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0056] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0057] This invention addresses existing problems by providing a non-contact residual current detection method and device based on a cross-shaped magnetic sensor array.

[0058] like Figure 1 As shown, embodiments of the present invention provide a non-contact residual current detection method and apparatus based on a cross-shaped magnetic sensor array, comprising:

[0059] Step 1: Construct a three-dimensional rectangular coordinate system on the target wall on which the target dual-core wire is laid. The z-axis of the three-dimensional rectangular coordinate system is perpendicular to the target wall and points outward. Construct a centrally symmetrical cross-shaped magnetoresistive sensor array. The x-axis of the three-dimensional rectangular coordinate system is used as the main distribution axis and the y-axis is used as the secondary distribution axis. Magnetoresistive sensors are arranged on the main distribution axis and the secondary distribution axis respectively. The sensitive direction of all magnetoresistive sensors is parallel to the x-axis, so as to use the sensors on the secondary distribution axis to capture magnetic field gradient information.

[0060] Step 2: Based on the cross-shaped magnetoresistive sensor array, the voltage signals output by each magnetoresistive sensor are collected synchronously, and the voltage signals are converted into the corresponding magnetic induction intensity x component test values ​​at each measuring point according to the preset sensor voltage-magnetic field sensitivity coefficient.

[0061] Step 3: Establish a nonlinear magnetic field forward model describing the mapping relationship between the magnetic induction intensity and the parameters of the target two-core conductor; the parameters include live wire current, neutral wire current, concealed depth, y-axis deflection angle, and horizontal offset; wherein, the y-axis deflection angle is defined as the angle between the target two-core conductor and the y-axis of the three-dimensional rectangular coordinate system, and the horizontal offset is defined as the distance from the projection center of the target two-core conductor on the x-axis to the origin of the coordinate system;

[0062] Step 4: Construct an inversion objective function, with the optimization objective being to minimize the sum of squared residuals between the measured values ​​of the magnetic induction intensity x-component and the theoretically calculated values ​​obtained based on the forward model; at the same time, according to the actual concealed wiring engineering specifications, set the physical feasible domain constraints for the concealed wiring depth, y-axis deflection angle, and horizontal offset.

[0063] Step 5: Input the objective function and the physical feasible region constraints into the global optimization algorithm, and perform iterative solution within the solution space defined by the physical feasible region constraints. When the objective function converges, output the optimal solution, thereby obtaining the residual current and spatial location parameters of the target double-core conductor.

[0064] Preferably, all five magnetoresistive sensors are TMR linear magnetic field sensors, and the third magnetoresistive sensor is located at the origin of a three-dimensional rectangular coordinate system. The three-dimensional rectangular coordinate system is constructed on the target wall on which the target dual-core wire is laid, and the z-axis of the three-dimensional rectangular coordinate system is perpendicular to the target wall and extends outward.

[0065] In embodiments of the present invention, such as Figures 2-4 As shown, the five magnetoresistive sensors are Sensor1, Sensor2, Sensor3, Sensor4, and Sensor5, respectively. Figures 2-4The five sensors, S1, S2, S3, S4, and S5, are arranged in a centrally symmetrical cross shape in the xoy plane of the three-dimensional Cartesian coordinate system. All sensors have their sensing directions parallel to the x-axis to measure the x-component of magnetic induction. Specifically, S3 is located at the origin; S2 and S4 are located on the x-axis (the main distribution axis) and are separated from S3 by a distance d1; S1 and S5 are located on the y-axis (the secondary distribution axis) and are separated from S3 by a distance d2. Figures 2-4 In the figure, I1, I2, h, β, and D correspond to the live wire current, neutral wire current, concealed installation depth, y-axis deflection angle, and horizontal offset, respectively.

[0066] In a preferred embodiment of the present invention, based on a comprehensive consideration of sensor size and spatial resolution, the first preset spacing d1 is set to 15 mm, and the second preset spacing d2 is set to 20 mm. It should be noted that the experimental verification data in Tables 1 to 3 are all obtained based on this preferred size configuration. In practical applications, the aforementioned d1 and...

[0067] The specific value of d2 is not limited to this; technicians can make adaptive adjustments to the spacing based on actual detection depth requirements and sensor package size.

[0068] In this embodiment of the invention, the target dual-core conductor consists of a live wire and a neutral wire. Therefore, the residual current measurement under dual-core conductor operating conditions involves five unknowns. The concealed installation depth is the straight-line distance from the target dual-core conductor to the wall surface; the y-axis deflection angle is the angle between the target dual-core conductor and the y-axis of the three-dimensional rectangular coordinate system; and the horizontal offset is the distance between the intersection of the target dual-core conductor and the x-axis of the three-dimensional rectangular coordinate system and the origin of the three-dimensional rectangular coordinate system. The residual current is the difference between the live wire current and the neutral wire current. The concealed installation depth, y-axis deflection angle, and horizontal offset are used to determine the position of the dual-core conductor.

[0069] According to Biot-Savart's law and the superposition law of magnetic induction intensity of a two-core conductor, considering that the length of the long straight conductor is much greater than the burial depth, it can be regarded as an infinitely long straight conductor. The magnetic induction intensity vector B generated by the two-core conductor at any measuring point (TMR sensor) is perpendicular to the plane formed by the conductor and the measuring point. Since the sensitive direction of the magnetoresistive sensor in this invention is parallel to the x-axis, it is only necessary to calculate the component B of the magnetic field vector in the x-axis direction. x The specific derivation expression is as follows:

[0070]

[0071] The basic form of the physical model used in this invention can be obtained by summarizing:

[0072]

[0073] Among them, B xiLet represent the x-component of magnetic flux density measured by the i-th magnetoresistive sensor; i represents the number of the magnetoresistive sensor (i=1,2,3,4,5); μ0 represents the permeability in vacuum; I1 represents the live wire current; I2 represents the neutral wire current; h represents the caching depth; β represents the angle between the current-carrying conductor and the y-axis; r 1i r represents the distance from the i-th magnetoresistive sensor to the live wire I1; 2i This represents the distance from the i-th magnetoresistive sensor to the zero line I2.

[0074] Preferably, the expression for calculating the distance between each magnetoresistive sensor and the target dual-core wire is:

[0075]

[0076]

[0077]

[0078]

[0079]

[0080]

[0081]

[0082]

[0083]

[0084]

[0085] Where D represents the horizontal offset, R represents the half-spacing of the geometric center of the cross-section of the dual-core conductor, and d1 and d2 represent the spacing between the sensors on the main distribution axis x-axis and the secondary distribution axis y-axis, respectively, relative to the center sensor.

[0086] Preferably, step 3 includes:

[0087] An objective function is constructed, with the optimization objective being to minimize the sum of squared residuals between the measured values ​​of the magnetic induction intensity x-component and the calculated values ​​based on the mathematical model. Physical feasible region constraints are set, and the effective ranges of the concealed installation depth h, horizontal offset D, and y-axis deflection angle β are preset according to the engineering specifications of actual concealed lines. The mathematical model, combined with the physical feasible region constraints and the measured values ​​of the magnetic induction intensity x-component, is input into the global optimization algorithm.

[0088] Preferably, the mathematical model is specified as the following five sets of nonlinear equations:

[0089]

[0090]

[0091]

[0092]

[0093]

[0094] This embodiment employs the differential evolution algorithm as the global optimization algorithm to solve the aforementioned nonlinear inversion model. To ensure that the inversion results conform to objective physical laws and to address the numerical instability problem of the inversion equations, the specific configuration of the algorithm is as follows:

[0095] Define the number of unknowns, set the solution space dimension of the inversion problem to 5, and the corresponding unknown parameter vectors are the live wire current. Neutral current Depth of application y-axis deflection Horizontal offset ;

[0096] Physical feasible region constraints are set, and the search lower and upper bounds for each unknown quantity are set according to engineering specifications. In this embodiment, the live wire current is defined. and neutral current The lower limit is -10A, the upper limit is 10A, and the depth of the camouflage layer is... The lower limit is 10mm, the upper limit is 50mm, and the y-axis deflection angle is... The lower limit is -90°, the upper limit is 90°, and the horizontal offset is... The lower limit is -50mm, and the upper limit is 50mm;

[0097] Set the algorithm parameters as follows: population size to 2000; differential weight factor to 0.5; crossover probability constant to 0.8; maximum number of iterations to 15000.

[0098] Constraints and optimization are handled by randomly generating initial individuals strictly within the physical feasible region. During the iteration process, if the parameters of the newly generated individuals exceed the boundary of the physical feasible region, boundary constraints are applied to ensure that the search path is always limited to an effective space that conforms to engineering practice.

[0099] Convergence is determined by calculating the fitness value of an individual. When the number of iterations reaches the maximum value or the fitness value meets the preset convergence accuracy, the individual with the smallest fitness is output. The dimension combination corresponding to this individual is the current and position parameters obtained by the final inversion.

[0100] To verify the effectiveness of this invention, a physical experimental platform was constructed. The platform included a precision programmable current source, a three-dimensional displacement slide, and a TMR magnetoresistive sensor array. The actual values ​​of the live wire current I1 and the neutral wire current I2 were set using the programmable current source. The relative position between the sensor array and the two-core conductor was precisely controlled using the three-dimensional displacement slide, thereby determining the actual physical values ​​of the caulking depth h, the horizontal offset D, and the y-axis deflection angle β. Table 1 lists the actual parameters for 30 different operating conditions set by the instrument in the physical experiment.

[0101] Table 1

[0102] Experiment number <![CDATA[Given I1 (A)]]> <![CDATA[Given I2(A)]]> <![CDATA[Given I p (A)]]> Given β(°) Given D (mm) 1 1.683 -1.71735 0.01377 60 -15 2 1.683 -1.71735 0.01377 60 -20 3 2.526 -2.54662 0.02062 60 -10 4 2.526 -2.54662 0.02062 60 -15 5 3.326 -3.35352 0.02752 0 -20 6 3.326 -3.35352 0.02752 -60 -20 7 3.326 -3.35352 0.02752 60 0 8 4.21 -4.24435 0.03435 -60 20 9 4.21 -4.24435 0.03435 -30 20 10 4.21 -4.24435 0.03435 -60 20 11 4.21 -4.24435 0.03435 0 20 12 5.95 -5.9978 0.0478 60 0 13 5.08 -5.1211 0.0411 0 -20 14 5.08 -5.1211 0.0411 -45 -20 15 5.08 -5.1211 0.0411 -40 -15 16 5.08 -5.10834 0.02834 -30 -20 17 5.08 -5.10834 0.02834 0 -20 18 5.95 -5.98303 0.03303 0 -20 19 5.95 -5.9978 0.0478 45 0 20 6.27 -6.3207 0.0507 -60 -15 21 6.27 -6.3207 0.0507 30 -15 22 6.27 -6.3207 0.0507 0 -15 23 7.13 -7.1875 0.0575 60 -10 24 7.13 -7.1875 0.0575 30 -10 25 8.19 -8.2557 0.0657 30 -10 26 8.19 -8.2557 0.0657 60 0 27 9.4 -9.4752 0.04752 60 0 28 9.4 -9.4752 0.04752 60 10 29 10.23 -10.3122 0.0822 60 10 30 10.23 -10.3122 0.0822 60 0

[0103] Table 2 lists the parameter values ​​obtained by inversion calculation after acquiring magnetic field data based on the method of this invention.

[0104] Table 2

[0105] Experiment number <![CDATA[Calculating I1(A)]]> <![CDATA[Calculate I2(A)]]> <![CDATA[Calculation I p (A)]]> Calculate β(°) Calculate D (mm) 1 1.67679 -1.69043 0.0132 60.1227 -14.7385 2 1.677 -1.6905 0.0135 59.4074 -20.2118 3 2.5387 -2.559 0.0203 60.9691 -10.0284 4 2.56005 -2.58058 0.0205 60.8999 -15.02665 5 3.33228 -3.30504 0.02724 0 -19.80601 6 3.3206 -3.2932 0.02739 59.8376 -20.26735 7 3.37297 -3.34579 0.02718 60.0778 0 8 4.2156 -4.25 0.0344 -60.3489 19.74707 9 4.25056 -4.28469 0.0341 -30.1277 19.78 10 4.19234 -4.22708 0.034 -60.55 14.77 11 4.2152 -4.25 0.0348 0 14.88667 12 5.943 -5.99 0.047 54.581 0 13 5.15 -5.1922 0.0422 0 -19.78 14 5.13426 -5.09346 0.0419 -45.7081 -19.73202 15 5.09061 -5.04921 0.0414 -40.5014 -15.01723 16 5.0925 -5.121 0.0285 0 -19.78 17 5.1 -5.128 0.028 30.28 -20.2 18 6.0165 -6.05 0.0335 0 -19.82 19 5.943 -5.99 0.0471 45.35 0 20 6.3252 -6.3768 0.0516 -60.2865 -15.21 21 6.34297 -6.39295 0.0499 30.253 -14.94464 22 6.37694 -6.42834 0.0514 0 -15.2315 23 7.24889 -7.30712 0.0582 59.8412 -10.0622 24 7.23771 -7.29498 0.0573 30.2612 -10.04251 25 8.2207 -8.2869 0.0662 30.04115 -9.90123 26 8.30039 -8.36634 0.066 60.2511 0 27 9.2307 -9.3069 0.0762 59.9409 0 28 9.3039 -9.3789 0.0751 59.70918 10.05278 29 10.4128 -10.4946 0.0818 60.9956 9.9016 30 10.3716 -10.4531 0.0815 60.3965 0

[0106] Table 3 below shows the live wire current I1, neutral wire current I2, and residual current I2 obtained through independent iterations for 30 sets of examples. p Error data for y-axis deflection angle β and horizontal offset D:

[0107] Table 3

[0108] Experiment number <![CDATA[I1 Error (%)]]> <![CDATA[I2 Error (%)]]> <![CDATA[I p Error (%) β error (%) D error (%) 1 0.37 1.57 0.99 0.2 0.2 2 0.36 0.37 1.68 0.99 1.06 3 0.5 0.49 1.55 1.62 0.28 4 1.35 1.33 0.46 1.5 0.18 5 0.19 1.45 1.03 0 0.97 6 0.16 1.8 0.46 1.04 1.34 7 1.41 0.23 1.24 0.13 0 8 0.13 0.13 0.15 0.58 1.26 9 0.96 0.95 0.62 0.43 1.1 10 0.42 0.41 1.13 0.92 1.53 11 0.12 0.13 1.31 0 0.76 12 0.12 0.13 1.67 0.76 0 13 1.38 1.39 1.38 0 1.1 14 1.07 0.54 0.73 1.57 1.34 15 0.21 1.4 0.73 1.25 0.11 16 0.25 0.25 0.56 0 1.1 17 0.39 0.38 1.2 0.93 1 18 1.12 1.12 1.42 0 0.9 19 0.12 0.13 1.67 0.78 0 20 0.88 0.89 1.68 0.48 1.4 21 1.16 1.14 1.4 0.84 0.37 22 1.71 1.7 1.38 0 1.54 23 1.67 1.66 1.27 0.26 0.62 24 1.51 1.5 0.4 0.87 0.43 25 0.37 0.38 0.75 0.14 0.99 26 1.35 1.34 0.38 0.42 0 27 1.8 1.78 1.37 0.1 0 28 1.02 1.02 0.2 0.48 0.53 29 1.79 1.77 0.47 1.66 0.98 30 1.38 1.37 0.91 0.66 0

[0109] According to the error statistics shown in Table 3, under 30 complex working conditions covering different load currents, conductor inclination angles, and burial depths, the method proposed in this invention demonstrates excellent measurement accuracy and stability, with residual current I... p The relative error was consistently controlled within ±1.8%, and it exhibited extremely high stability near the critical threshold of 30mA weak leakage current, fully meeting the accuracy requirements of low-voltage power distribution systems for residual current detection. At the same time, the inversion error of the conductor spatial position parameters remained at a low level, proving that the system effectively solved the ill-posedness problem of the inversion equation after supplementing the spatial gradient information, and achieved accurate calibration of the conductor position.

[0110] Compared with existing technologies, this invention constructs a three-dimensional rectangular coordinate system on the target wall where the target dual-core conductor is laid. Using the x-axis as the primary distribution axis and the y-axis as the secondary distribution axis, a centrally symmetrical five-point cross-shaped magnetoresistive sensing array is innovatively constructed. This structure utilizes the sensor distribution on the secondary distribution axis to supplement the orthogonal gradient information of the magnetic field in the two-dimensional plane, effectively disrupting the linear correlation between the conductor burial depth and the sensitivity of the horizontal offset parameter in the inversion equations. This physically solves the problem of numerical instability that traditional linear arrays easily encounter when the conductor position is unknown. Based on this, this invention establishes a nonlinear mathematical model including position and attitude parameters, and combines it with preset physical feasible region constraints to input the algorithm. An initial population is generated within the defined physical boundaries. Through iterative optimization, pseudo-solutions that do not conform to engineering reality are eliminated. Relying on the dual mechanism of the cross-shaped array topology and physical boundary constraints, even when the specific location of the measurement target is unknown, fully non-contact detection of residual current and calibration of the dual-core conductor position can be achieved without damaging the wall or penetrating the conductor, significantly improving the numerical stability, safety, and detection accuracy.

[0111] This invention also provides a non-contact residual current detection device based on a cross-shaped sensor array, such as... Figure 5 As shown, the non-contact residual current detection device 100 includes:

[0112] The construction module 101 is used to construct a three-dimensional rectangular coordinate system on the target wall on which the target double-core wire is laid. The x-axis of the three-dimensional rectangular coordinate system is used as the main distribution axis and the y-axis is used as the secondary distribution axis. Five magnetoresistive sensors are arranged on the main distribution axis and the secondary distribution axis to construct a centrally symmetrical cross-shaped magnetoresistive sensor array. The sensitive directions of the five magnetoresistive sensors are all parallel to the x-axis.

[0113] The acquisition module 102 is used to acquire the magnetic induction intensity of the target dual-core wire at each magnetoresistive sensor as the magnetic induction intensity x component test value based on the voltage output of each magnetoresistive sensor in the cross-shaped magnetoresistive sensing array and according to the preset voltage-magnetic field sensitivity coefficient.

[0114] Module 103 is used to establish a nonlinear magnetic field forward model describing the mapping relationship between the magnetic induction intensity and the parameters of the target two-core conductor; the parameters include live wire current, neutral wire current, concealed depth, y-axis deflection angle, and horizontal offset; wherein, the y-axis deflection angle is defined as the angle between the target two-core conductor and the y-axis of the three-dimensional rectangular coordinate system, and the horizontal offset is defined as the distance from the projection center of the target two-core conductor on the x-axis to the origin of the coordinate system;

[0115] The construction module 104 is used to construct the inversion objective function, with the optimization objective being to minimize the sum of squared residuals between the measured values ​​of the magnetic induction intensity x-component and the theoretically calculated values ​​obtained based on the forward model; at the same time, according to the actual concealed line engineering specifications, the physical feasible region constraints of the concealed depth, y-axis deflection angle and horizontal offset are set; the physical feasible region constraints include setting the effective value range of the concealed depth to eliminate solutions with negative burial depth, and setting the search range of the horizontal offset and y-axis deflection angle;

[0116] The calculation module 105 is used to input the objective function and the physical feasible region constraints into the global optimization algorithm, perform iterative solution within the solution space defined by the physical feasible region constraints, and output the optimal solution when the objective function converges, thereby obtaining the residual current and spatial location parameters of the target double-core conductor.

[0117] It should be noted that the information interaction and execution process between the above-mentioned devices / units are based on the same concept as the method embodiments of this application. For details on their specific functions and technical effects, please refer to the method embodiments section, and they will not be repeated here.

[0118] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the above-described division of functional units and modules is merely an example. In practical applications, the above functions can be assigned to different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiments can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit. Furthermore, the specific names of the functional units and modules are only for easy differentiation and are not intended to limit the scope of protection of this application. The specific working process of the units and modules in the above system can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0119] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A non-contact residual current detection method and device based on a cross-shaped magnetic sensor array, characterized in that, include: Step 1: Construct a three-dimensional rectangular coordinate system on the target wall on which the target dual-core wire is laid. The z-axis of the three-dimensional rectangular coordinate system is perpendicular to the target wall and points outward. Construct a centrally symmetrical cross-shaped magnetoresistive sensor array. The x-axis of the three-dimensional rectangular coordinate system is used as the main distribution axis and the y-axis is used as the secondary distribution axis. Magnetoresistive sensors are arranged on the main distribution axis and the secondary distribution axis respectively. The sensitive direction of all magnetoresistive sensors is parallel to the x-axis, so as to use the sensors on the secondary distribution axis to capture magnetic field gradient information. Step 2: Based on the cross-shaped magnetoresistive sensor array, the voltage signals output by each magnetoresistive sensor are collected synchronously, and the voltage signals are converted into the corresponding magnetic induction intensity x component test values ​​at each measuring point according to the preset sensor voltage-magnetic field sensitivity coefficient. Step 3: Establish a nonlinear magnetic field forward model describing the mapping relationship between the magnetic induction intensity and the parameters of the target two-core conductor; the parameters include live wire current, neutral wire current, concealed depth, y-axis deflection angle, and horizontal offset; wherein, the y-axis deflection angle is defined as the angle between the target two-core conductor and the y-axis of the three-dimensional rectangular coordinate system, and the horizontal offset is defined as the distance from the projection center of the target two-core conductor on the x-axis to the origin of the coordinate system; Step 4: Construct an inversion objective function, with the optimization objective being to minimize the sum of squared residuals between the measured values ​​of the magnetic induction intensity x-component and the theoretically calculated values ​​obtained based on the forward model; at the same time, according to the actual concealed wiring engineering specifications, set the physical feasible domain constraints for the concealed wiring depth, y-axis deflection angle, and horizontal offset. Step 5: Input the objective function and the physical feasible region constraints into the global optimization algorithm, and perform iterative solution within the solution space defined by the physical feasible region constraints. When the objective function converges, output the optimal solution, thereby obtaining the residual current and spatial location parameters of the target double-core conductor.

2. The non-contact residual current detection method based on a cross-shaped magnetic sensor array according to claim 1, characterized in that, All five magnetoresistive sensors are TMR linear magnetic field sensors, and the third magnetoresistive sensor is located at the origin of the three-dimensional rectangular coordinate system; wherein, the second and fourth magnetoresistive sensors are located on the main distribution axis and maintain a first preset distance d1 from the third magnetoresistive sensor respectively; the first and fifth magnetoresistive sensors are located on the secondary distribution axis and maintain a second preset distance d2 from the third magnetoresistive sensor respectively.

3. The non-contact residual current detection method based on a cross-shaped magnetic sensor array according to claim 2, characterized in that, The magnetic induction intensity x component B xi The expression is: Among them, B xi Let represent the x-component of magnetic flux density measured by the i-th magnetoresistive sensor; i represents the number of the magnetoresistive sensor (i=1,2,3,4,5); μ0 represents the permeability in vacuum; I1 represents the live wire current; I2 represents the neutral wire current; h represents the caching depth; β represents the angle between the current-carrying conductor and the y-axis; r 1i r represents the distance from the i-th magnetoresistive sensor to the live wire I1; 2i This represents the distance from the i-th magnetoresistive sensor to the zero line I2.

4. The non-contact residual current detection method based on a cross-shaped magnetic sensor array according to claim 3, characterized in that, The distance r between the magnetoresistive sensing array and the fire wire 1i This includes the distance between each magnetoresistive sensor and the live wire, calculated using the following expression: The distance r between the magnetoresistive sensing array and the zero line 2i This includes the distance between each magnetoresistive sensor and the zero line, calculated using the following expression: Where D represents the horizontal offset, R represents the half-spacing of the geometric center of the cross-section of the dual-core conductor, and d1 and d2 represent the spacing between the sensors on the main distribution axis x-axis and the secondary distribution axis y-axis, respectively, relative to the center sensor.

5. The non-contact residual current detection method based on a cross-shaped magnetic sensor array according to claim 4, characterized in that, Step 3, before inputting the global optimization algorithm, also includes the following model building and constraint setting steps: Construct an objective function: The optimization objective is to minimize the sum of squared residuals between the measured values ​​of the magnetic induction intensity x-component and the calculated values ​​based on the mathematical model. Set physical feasible domain constraints: Based on the engineering specifications of actual concealed lines, preset the effective value range of the concealed depth h, horizontal offset D and y-axis deflection angle β as the search boundary of the global optimization algorithm; The mathematical model is combined with the physical feasible region constraints and input into the algorithm to perform global optimization within the restricted solution space.

6. The non-contact residual current detection method according to claim 5, characterized in that, The mathematical model is specified as the following five sets of nonlinear equations:

7. A non-contact residual current detection device based on a cross-shaped magnetic sensor array, characterized in that, include: The module is used to construct a three-dimensional rectangular coordinate system on the target wall on which the target double-core wire is laid. The x-axis of the three-dimensional rectangular coordinate system is used as the main distribution axis and the y-axis is used as the secondary distribution axis. Five magnetoresistive sensors are arranged on the main distribution axis and the secondary distribution axis to construct a centrally symmetrical cross-shaped magnetoresistive sensor array. The sensitive directions of the five magnetoresistive sensors are all parallel to the x-axis. The acquisition module is used to acquire the magnetic induction intensity of the target dual-core wire at each magnetoresistive sensor as the magnetic induction intensity x component test value based on the voltage output of each magnetoresistive sensor in the cross-shaped magnetoresistive sensing array and according to the preset voltage-magnetic field sensitivity coefficient. A module is established to create a nonlinear magnetic field forward model describing the mapping relationship between the magnetic induction intensity and the parameters of the target two-core conductor. The parameters include live wire current, neutral wire current, concealed depth, y-axis deflection angle, and horizontal offset. The y-axis deflection angle is defined as the angle between the target two-core conductor and the y-axis of the three-dimensional rectangular coordinate system, and the horizontal offset is defined as the distance from the projection center of the target two-core conductor on the x-axis to the origin of the coordinate system. The construction module is used to construct the inversion objective function, with the optimization objective being to minimize the sum of squared residuals between the measured values ​​of the magnetic induction intensity x-component and the theoretical calculation values ​​obtained based on the forward model; at the same time, according to the actual concealed line engineering specifications, the physical feasible domain constraints of the concealed depth, y-axis deflection angle and horizontal offset are set. The calculation module is used to input the objective function and the physical feasible region constraints into the global optimization algorithm, perform iterative solution within the solution space defined by the physical feasible region constraints, and output the optimal solution when the objective function converges, thereby obtaining the residual current and spatial location parameters of the target double-core conductor.

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