High-stability electric power system single-phase current-carrying wire current information sensing method and device

Abstract

The invention discloses a high-stability electric power system single-phase current-carrying wire current information sensing method and device, and belongs to the technical field of electric power system current measurement. The invention discloses a high-stability electric power system single-phase current-carrying wire current information sensing method, and the method comprises the steps: forming a linear chip array through magnetic resistance chips, and obtaining the parameters of the chip array; a sensing probe carrying a chip array is arranged near a detected single-phase current-carrying wire, and the output voltage of each magnetic resistance chip after signal conditioning and amplification is read through a sampling circuit; constructing a reverse calculation equation set considering magnetic field interference by combining a superposition relationship between a measured wire magnetic field and an interference magnetic field; and performing differential operation on the inverse calculation equation set to suppress magnetic field interference, and solving the equation to obtain the magnitude of the current to be measured. By adopting the high-stability electric power system single-phase current-carrying wire current information sensing method and device, the problems that the existing current information measurement operation is inconvenient and the measurement precision is low can be solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power system current measurement, in particular to a high-stability power system single-phase current-carrying conductor current information sensing method and device. BACKGROUND

[0002] With the large-scale integration of distributed power into the power system, the proportion of renewable energy in the power system is rising, and the complexity and dynamics of power grid operation are significantly enhanced, so the sensing of current-carrying conductor current information needs to have higher real-time synchronization, higher measurement accuracy, higher response speed and higher installation convenience.

[0003] Currently, the synchronous phasor measurement device is mostly deployed in high-voltage transmission substations, and the coverage of high-voltage transmission line current level monitoring is wide, but the monitoring range of current information in new power systems with high proportion of new energy is still very limited, and the current measurement point range needs to be further expanded. However, such areas generally have the characteristics of wide distribution of to-be-measured point space range and complex network topology structure, and the number of monitoring points is much larger than that of high-voltage transmission networks; at the same time, the electromagnetic environment at the measurement point in the power system is complex, and the influence of external interference sources needs to be overcome during current information sensing to ensure accuracy. Therefore, the current monitoring in the current new power system faces the realistic problems of large point scale, large number of points, and poor electromagnetic environment. The traditional current transformer has problems such as high manufacturing cost, large metal consumption, complicated installation process, and poor measurement accuracy, and it is difficult to meet the needs of flexible deployment of new power systems. And for safety considerations, the power supply needs to be cut off when installing the current transformer, and the operation convenience is poor. Therefore, the existing monitoring device cannot realize accurate monitoring of the current in the existing new power system. SUMMARY

[0004] The purpose of the present application is to provide a high-stability power system single-phase current-carrying conductor current information sensing method and device, which solves the problems of inconvenient current information measurement operation and low measurement accuracy.

[0005] To achieve the above-mentioned purpose, the present application provides a high-stability power system single-phase current-carrying conductor current information sensing method, comprising the following steps: S1, a linear chip array is formed by using a magnetoresistance chip to obtain chip array parameters; S2, a sensing probe carrying the chip array is placed near the measured single-phase current-carrying conductor, and the output voltage of each magnetoresistance chip after signal conditioning and amplification is read by a sampling circuit; S3, combining the superposition relationship of the measured conductor magnetic field and the interference magnetic field, an inverse calculation equation set considering magnetic field interference is constructed; S4. Perform differential operations on the inverse calculation equations to suppress magnetic field interference. Substitute the chip array parameters obtained in S1 and the output voltage read in S2 to solve the equations and obtain the magnitude of the current to be measured.

[0006] Preferably, in S1, the chip array includes five single-axis magnetoresistive chips, which are distributed in space along a straight line. The sensitive directions of the five single-axis magnetoresistive chips are in the same direction and are parallel to the distribution line of the single-axis magnetoresistive chips.

[0007] Preferably, the chip array parameters include the distance between two adjacent uniaxial magnetoresistive chips, the supply voltage of the uniaxial magnetoresistive chip, and the sensitivity coefficient of the uniaxial magnetoresistive chip; the spacing between two adjacent uniaxial magnetoresistive chips is on the same order of magnitude as the diameter of the single-phase current-carrying conductor being measured.

[0008] Preferably, in step S2, the distance between the sensing probe and the single-phase current-carrying conductor being measured is on the same order of magnitude as the diameter of the single-phase current-carrying conductor being measured, and the spatial position of the sensing probe remains unchanged during the sensing process; the magnitude of the output voltage of each single-axis magnetoresistive chip is proportional to the magnitude of the component of the magnetic field strength at its location along its sensitive direction.

[0009] Preferably, in step S3, the specific process of constructing the inverse calculation equation set considering magnetic field interference is as follows: S31. The single-phase current-carrying conductor to be measured is modeled as a wireless long straight cylindrical conductor. According to Ampere's circuital law, the relationship between the magnitude of the current to be measured and the magnitude of the magnetic field strength generated by the single-phase current-carrying conductor at each uniaxial magnetoresistive chip is obtained. S32. The magnetic field generated by the current to be measured is superimposed with the interference magnetic field and projected onto the sensitive direction of the uniaxial magnetoresistive chip to obtain the component of the magnetic field intensity along the sensitive direction at each uniaxial magnetoresistive chip. S33. Calculate the abscissa and ordinate of each single-axis magnetoresistive chip based on the geometric relationship of the single-axis magnetoresistive chip array formed by the distance between two adjacent single-axis magnetoresistive chips, and substitute the abscissa and ordinate into the component expression of the magnetic field intensity along the sensitive direction at each single-axis magnetoresistive chip to obtain the inverse calculation equation set.

[0010] Preferably, in step S31, the relationship between the magnitude of the current to be measured and the magnitude of the magnetic field strength generated by the single-phase current-carrying conductor at each uniaxial magnetoresistive chip is as follows: ; in, The magnitude of the measured current. ~ These represent the distances between each uniaxial magnetoresistive chip and the axis of the single-phase current-carrying conductor under test. ~ These represent the magnitudes of the magnetic field strength generated by the measured current at each uniaxial magnetoresistive chip. It is a line element vector.

[0011] Preferably, in step S32, the coordinates of the locations of the single-axis magnetoresistive chips 1 to 5 are respectively... P 1( x 1,0,0), P 2( x 2, y 2, z 2), P 3( x 3, y 3, z 3), P 4( x 4, y 4, z 4), P 5( x 5, y 5, z 5), m 1~ m 4 represents the spacing between single-axis magnetoresistive chips 1, 2, 3, 4, and 5, respectively. The components of the magnetic field strength along the sensitive direction at single-axis magnetoresistive chips 1 to 5 are as follows: ; in, For the sensitive direction of a uniaxial magnetoresistive chip, ; ~ These represent the magnitudes of the magnetic field strength components along the sensitive direction of the uniaxial magnetoresistive chips at locations 1 through 5. To interfere with the magnetic field strength.

[0012] Preferably, in step S33, the expressions for the horizontal and vertical coordinates of the uniaxial magnetoresistive chips No. 3 to No. 5 are as follows: ; ; The inverse calculation system of equations is as follows: .

[0013] Preferably, in step S4, the specific process of performing difference operations on the inverse calculation equation system is as follows: Will respectively with , , , Taking the difference, we obtain the difference equation: ; in, ~ These are the output voltage sampling values ​​of single-axis magnetoresistive chips 1 through 5, respectively. k This represents the sensitivity coefficient of a single-axis magnetoresistive chip.

[0014] A sensing device applicable to the above-mentioned high-stability power system single-phase current-carrying conductor current information sensing method includes, The chip array includes five uniaxial magnetoresistive chips for sensing the component of the magnetic field strength around the conductor under test along the sensitive direction. The printed circuit board serves as the sensor probe, on which a chip array, a signal conditioning and amplification circuit, and a sampling unit are mounted. The signal conditioning and amplification circuit is electrically connected to the chip array and is used to filter out noise from the output signal of the magnetoresistive chip and amplify the effective signal. The sampling unit is electrically connected to the signal conditioning and amplification circuit and is used to convert the amplified analog voltage signal into a digital voltage signal. A DC power supply, connected to the printed circuit board, provides a stable power supply for the chip array, signal conditioning and amplification circuits, and sampling unit; The host computer is connected to the sampling unit and is used to read the voltage digital signal and calculate the current to be measured by combining the geometric information of the chip array and the sensitivity coefficient of the magnetoresistive chip.

[0015] The advantages and positive effects of the high-stability power system single-phase current-carrying conductor current information sensing method and device described in this invention are: 1. This invention employs a five-single-axis magnetoresistive chip array and differential operation technology. By differentially processing the magnetic field signal, it can effectively cancel out external interference magnetic fields. Even in complex electromagnetic environments, it can still accurately capture the real current magnetic field of the conductor under test, avoid measurement deviations caused by interference, and ensure the accuracy of current information.

[0016] 2. This invention uses printed circuit board sensing probes and non-contact measurement methods, which greatly reduces the operation and maintenance costs and power outage losses of power systems. It can be flexibly deployed in scenarios such as power transmission and distribution lines and equipment power supply circuits, and is convenient to operate and use.

[0017] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0018] Figure 1 This is a flowchart of the sensing method according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the chip array structure of an embodiment of the present invention; Figure 3 This is a schematic diagram of the sensing device structure according to an embodiment of the present invention. Detailed Implementation

[0019] In this application, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. In case of any inconsistency, the meaning set forth in this specification or derived from the content described herein shall prevail. Furthermore, the terminology used herein is for the purpose of describing embodiments of this application only and is not intended to limit the scope of this application.

[0020] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0021] like Figure 1 As shown, a method for sensing the current information of a single-phase current-carrying conductor in a highly stable power system includes the following steps: S1. Use magnetoresistive chips to construct a linear chip array and obtain the chip array parameters.

[0022] The chip array includes five uniaxial magnetoresistive chips, which are distributed in space along a straight line. The sensitive directions of the five uniaxial magnetoresistive chips are in the same direction and are parallel to the straight line where the uniaxial magnetoresistive chips are distributed.

[0023] The chip array parameters include the distance between two adjacent uniaxial magnetoresistive chips, the supply voltage of the uniaxial magnetoresistive chips, and the sensitivity coefficient of the uniaxial magnetoresistive chips. The spacing between two adjacent uniaxial magnetoresistive chips is on the same order of magnitude as the diameter of the single-phase current-carrying conductor being measured.

[0024] S2. Place the sensor probe equipped with the chip array near the single-phase current-carrying conductor to be measured, and read the output voltage of each magnetoresistive chip after signal conditioning and amplification through the sampling circuit.

[0025] Five uniaxial magnetoresistive chips are soldered onto a printed circuit board as sensing probes. The distance between the sensing probe and the single-phase current-carrying conductor being measured is on the same order of magnitude as the diameter of the conductor, and the spatial position of the sensing probe remains constant during sensing. The magnitude of the output voltage of each uniaxial magnetoresistive chip is proportional to the magnitude of the component of the magnetic field strength at its location along its sensitive direction.

[0026] S3. Combining the superposition relationship between the magnetic field of the conductor under test and the interfering magnetic field, construct a set of inverse calculation equations that take into account magnetic field interference.

[0027] The specific process of constructing the inverse calculation equation set considering magnetic field interference is as follows: S31. If the single-phase current-carrying conductor to be measured is modeled as a long, straight cylindrical conductor, then the direction of the magnetic field strength around the single-phase current-carrying conductor to be measured can be determined according to the current direction and Ampere's law.

[0028] For a certain distance d The distance from the conductor in the space surrounding the conductor is... dThe magnitude of the magnetic field strength is the same at all points. Therefore, when integrating the magnetic field strength along a circular path coaxial with the single-phase current-carrying conductor being measured, the magnitude of the magnetic field strength remains unchanged, and the direction of the magnetic field strength is collinear with the direction of the integration path.

[0029] According to Ampere's circuital law, the relationship between the magnitude of the measured current and the magnetic field strength generated by the single-phase current-carrying conductor at each uniaxial magnetoresistive chip is as follows: ; in, The magnitude of the measured current. ~ These represent the distances between each uniaxial magnetoresistive chip and the axis of the single-phase current-carrying conductor under test. ~ These represent the magnitudes of the magnetic field strength generated by the measured current at each uniaxial magnetoresistive chip. It is a line element vector.

[0030] S32. The magnetic field generated by the current to be measured is superimposed with the interference magnetic field and projected onto the sensitive direction of the uniaxial magnetoresistive chip to obtain the component of the magnetic field intensity along the sensitive direction at each uniaxial magnetoresistive chip.

[0031] Since the parameters such as the size of the uniaxial magnetoresistive chip in the sensing probe, the spacing between each uniaxial magnetoresistive chip, and the distance between the sensing probe and the single-phase current-carrying conductor under test are much smaller than the distance between the uniaxial magnetoresistive chip and the interference source of the adjacent line, the interference magnetic field strength at the location of each uniaxial magnetoresistive chip is taken to be equal in magnitude and in the same direction.

[0032] like Figure 2 As shown, the coordinates of the locations of single-axis magnetoresistive chips 1 to 5 are respectively P 1( x 1,0,0), P 2( x 2, y 2, z 2), P 3( x 3, y 3, z 3), P 4( x 4, y 4, z 4), P 5( x 5, y 5, z 5), m 1~ m4 represents the spacing between the 1st and 5th single-axis magnetoresistive chips, respectively. Since the arrangement direction of the single-axis magnetoresistive chip array is parallel to the sensitive direction, the sensitive direction of the single-axis magnetoresistive chip... for .

[0033] According to the Biot-Savart theorem, the directions of the magnetic field strength generated by the measured current at uniaxial magnetoresistive chips 1 through 5 are as follows: ; in, The current direction reference vector, ~ These are the coordinates of the single-axis magnetoresistive chips numbered 1 through 5.

[0034] The magnetic field strength generated by the current to be measured at the uniaxial magnetoresistive chips 1 to 5 is as follows: ; The magnetic field generated by the current under test is superimposed with the interference magnetic field. The component of the magnetic field strength along the sensitive direction at the single-axis magnetoresistive chips 1 to 5 is as follows: ; in, ~ These represent the magnitudes of the magnetic field strength components along the sensitive direction of the uniaxial magnetoresistive chips at locations 1 through 5. To interfere with the magnetic field strength.

[0035] S33. Calculate the abscissa and ordinate of each single-axis magnetoresistive chip based on the geometric relationship of the single-axis magnetoresistive chip array formed by the distance between two adjacent single-axis magnetoresistive chips, and substitute the abscissa and ordinate into the component expression of the magnetic field intensity along the sensitive direction at each single-axis magnetoresistive chip to obtain the inverse calculation equation set.

[0036] The geometric relationship of a single-axis magnetoresistive chip array is as follows: ; The x-axis and y-axis expressions for single-axis magnetoresistive chips No. 3 to No. 5 are obtained as follows: ; .

[0037] Substituting the expressions for the x and y coordinates of uniaxial magnetoresistive chips 3 through 5 into the expressions for the components of the magnetic field intensity along the sensitive direction at uniaxial magnetoresistive chips 1 through 5, we obtain the inverse calculation equations: .

[0038] S4. Perform differential operations on the inverse calculation equations to suppress magnetic field interference. Substitute the chip array parameters obtained in S1 and the output voltage read in S2 to solve the equations and obtain the magnitude of the current to be measured.

[0039] The specific process of performing difference operations on the inverse calculation system of equations is as follows: Will respectively with , , , Taking the difference, we obtain the difference equation: ; in, ~ These are the output voltage sampling values ​​of single-axis magnetoresistive chips 1 through 5, respectively. k This represents the sensitivity coefficient of a single-axis magnetoresistive chip.

[0040] In the above difference equation, there exists , , and There are four unknowns and four equations, so the system of equations can be solved numerically using Newton's method to obtain the current to be measured. Size.

[0041] like Figure 3 As shown, a sensing device for sensing single-phase current-carrying conductor current information in the aforementioned high-stability power system includes, The chip array, comprising five uniaxial magnetoresistive chips, is used to sense the component of the magnetic field strength around the conductor under test along the sensitive direction.

[0042] The printed circuit board (PCB) serves as the sensor probe, housing a chip array, signal conditioning and amplification circuitry, and a sampling unit. The signal conditioning and amplification circuitry is electrically connected to the chip array, used to filter out noise from the magnetoresistive chip's output signal and amplify the effective signal. The sampling unit is electrically connected to the signal conditioning and amplification circuitry, used to convert the amplified analog voltage signal into a digital voltage signal. The power supply pins of all single-axis magnetoresistive chips are led out from the PCB and connected to a DC power supply with a matching voltage. The output voltage signal pins of all single-axis magnetoresistive chips are led out from the PCB and connected to the signal conditioning and amplification circuitry.

[0043] The DC power supply, connected to the printed circuit board, provides a stable power supply to the chip array, signal conditioning and amplification circuits, and sampling units. The DC power supply should include a filter to suppress ripple.

[0044] The host computer is connected to the sampling unit and is used to read the voltage digital signal and calculate the current to be measured by combining the geometric information of the chip array and the sensitivity coefficient of the magnetoresistive chip.

[0045] Therefore, the high-stability power system single-phase current-carrying conductor current information sensing method and device described in this invention can solve the problems of inconvenient operation and low measurement accuracy of existing current information measurement.

[0046] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for sensing current information of a single-phase current-carrying conductor in a high-stability power system, characterized in that, Includes the following steps: S1. Use magnetoresistive chips to construct a linear chip array and obtain the chip array parameters; S2. Place the sensor probe equipped with the chip array near the single-phase current-carrying conductor to be measured, and read the output voltage of each magnetoresistive chip after signal conditioning and amplification through the sampling circuit; S3. Combining the superposition relationship between the magnetic field of the conductor under test and the interfering magnetic field, construct a set of inverse calculation equations that take into account magnetic field interference. S4. Perform differential operations on the inverse calculation equations to suppress magnetic field interference. Substitute the chip array parameters obtained in S1 and the output voltage read in S2 to solve the equations and obtain the magnitude of the current to be measured.

2. The method for sensing current information of a single-phase current-carrying conductor in a high-stability power system according to claim 1, characterized in that: In S1, the chip array includes five single-axis magnetoresistive chips, which are distributed in space along a straight line. The sensitive directions of the five single-axis magnetoresistive chips are in the same direction and are parallel to the straight line where the single-axis magnetoresistive chips are distributed.

3. The method for sensing current information of a single-phase current-carrying conductor in a high-stability power system according to claim 2, characterized in that: The chip array parameters include the distance between two adjacent single-axis magnetoresistive chips, the power supply voltage of the single-axis magnetoresistive chip, and the sensitivity coefficient of the single-axis magnetoresistive chip; the spacing between two adjacent single-axis magnetoresistive chips is on the same order of magnitude as the diameter of the single-phase current-carrying conductor being measured.

4. The method for sensing current information of a single-phase current-carrying conductor in a high-stability power system according to claim 3, characterized in that: In S2, the distance between the sensing probe and the single-phase current-carrying conductor being measured is on the same order of magnitude as the diameter of the single-phase current-carrying conductor being measured, and the spatial position of the sensing probe remains unchanged during the sensing process; the magnitude of the output voltage of each single-axis magnetoresistive chip is proportional to the magnitude of the component of the magnetic field strength at its location along its sensitive direction.

5. A method for sensing current information of a single-phase current-carrying conductor in a high-stability power system according to claim 4, characterized in that, In S3, the specific process of constructing the inverse calculation equation set considering magnetic field interference is as follows: S31. The single-phase current-carrying conductor to be measured is modeled as a wireless long straight cylindrical conductor. According to Ampere's circuital law, the relationship between the magnitude of the current to be measured and the magnitude of the magnetic field strength generated by the single-phase current-carrying conductor at each uniaxial magnetoresistive chip is obtained. S32. The magnetic field generated by the current to be measured is superimposed with the interference magnetic field and projected onto the sensitive direction of the uniaxial magnetoresistive chip to obtain the component of the magnetic field intensity along the sensitive direction at each uniaxial magnetoresistive chip. S33. Calculate the abscissa and ordinate of each single-axis magnetoresistive chip based on the geometric relationship of the single-axis magnetoresistive chip array formed by the distance between two adjacent single-axis magnetoresistive chips, and substitute the abscissa and ordinate into the component expression of the magnetic field intensity along the sensitive direction at each single-axis magnetoresistive chip to obtain the inverse calculation equation set.

6. A method for sensing current information of a single-phase current-carrying conductor in a high-stability power system according to claim 5, characterized in that, In step S31, the relationship between the magnitude of the current to be measured and the magnitude of the magnetic field strength generated by the single-phase current-carrying conductor at each uniaxial magnetoresistive chip is as follows: ； in, The magnitude of the measured current. ~ These represent the distances between each uniaxial magnetoresistive chip and the axis of the single-phase current-carrying conductor under test. ~ These represent the magnitudes of the magnetic field strength generated by the measured current at each uniaxial magnetoresistive chip. It is a line element vector.

7. A method for sensing current information of a single-phase current-carrying conductor in a high-stability power system according to claim 6, characterized in that, In step S32, the coordinates of the locations of single-axis magnetoresistive chips 1 through 5 are respectively... P 1( x 1,0,0), P 2( x 2, y 2, z 2), P 3( x 3, y 3, z 3), P 4( x 4, y 4, z 4), P 5( x 5, y 5, z 5), m 1~ m 4 represents the spacing between single-axis magnetoresistive chips 1, 2, 3, 4, and 5, respectively. The components of the magnetic field strength along the sensitive direction at single-axis magnetoresistive chips 1 to 5 are as follows: ； in, For the sensitive direction of a uniaxial magnetoresistive chip, ; ~ These represent the magnitudes of the magnetic field strength components along the sensitive direction of the uniaxial magnetoresistive chips at locations 1 through 5. To interfere with the magnetic field strength.

8. A method for sensing current information of a single-phase current-carrying conductor in a high-stability power system according to claim 7, characterized in that, In S33, the expressions for the horizontal and vertical coordinates of the single-axis magnetoresistive chips No. 3 to No. 5 are as follows: ； ； The inverse calculation system of equations is as follows: 。 9. A method for sensing current information of a single-phase current-carrying conductor in a high-stability power system according to claim 8, characterized in that, In step S4, the specific process of performing difference operations on the inverse calculation system of equations is as follows: Will respectively with , , , Taking the difference, we obtain the difference equation: ； in, ~ These are the output voltage sampling values ​​of single-axis magnetoresistive chips 1 through 5, respectively. k This represents the sensitivity coefficient of a single-axis magnetoresistive chip.

10. A sensing device for sensing the current information of a single-phase current-carrying conductor in a high-stability power system as described in claim 9, characterized in that: include, The chip array includes five uniaxial magnetoresistive chips for sensing the component of the magnetic field strength around the conductor under test along the sensitive direction. The printed circuit board serves as the sensor probe, on which a chip array, a signal conditioning and amplification circuit, and a sampling unit are mounted. The signal conditioning and amplification circuit is electrically connected to the chip array and is used to filter out noise from the output signal of the magnetoresistive chip and amplify the effective signal. The sampling unit is electrically connected to the signal conditioning and amplification circuit and is used to convert the amplified analog voltage signal into a digital voltage signal. A DC power supply, connected to the printed circuit board, provides a stable power supply for the chip array, signal conditioning and amplification circuits, and sampling unit; The host computer is connected to the sampling unit and is used to read the voltage digital signal and calculate the current to be measured by combining the geometric information of the chip array and the sensitivity coefficient of the magnetoresistive chip.

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