A power system transmission and distribution line single-phase current synchronous phasor fast sensing method and device

Abstract

This invention discloses a method and device for rapid synchronous phasor sensing of single-phase current in power system transmission and distribution lines, belonging to the field of current measurement technology. The method includes: constructing a current sensing probe using TMR chips and measuring the spacing between the chips; placing a printed circuit board carrying the current sensing probe at the line under test and acquiring the instantaneous output voltage values ​​of each TMR chip; calculating the phase of the current phasor under test based on the instantaneous output voltage values ​​of the TMR chips; and calculating the amplitude of the current phasor under test based on the instantaneous output voltage values ​​of the TMR chips and the spacing between the chips. The method and device for rapid synchronous phasor sensing of single-phase current in power system transmission and distribution lines described in this invention can solve the problems of poor installation convenience and complex calculation processes in existing current phasor sensing methods.

Description

Technical Field

[0001] This invention relates to the field of current measurement technology, and in particular to a method and device for rapid synchronous phasor sensing of single-phase current in power transmission and distribution lines. Background Technology

[0002] In recent years, driven by the national strategic need to build a new power system and to solidly advance the process of cleaner and greener energy production, a massive number of distributed power sources have been connected to the power system. The large number and wide distribution of nodes to be measured in this new power system, which incorporates a large number of distributed power sources, necessitates that measurement devices have greater ease of installation.

[0003] Traditional methods for measuring the synchronous phasor of transmission and distribution line currents based on current transformers have been widely used in monitoring devices for the operation status of transmission and distribution lines at all levels. However, the current transformer-based method not only consumes a lot of copper and is heavy, requiring power-off installation, but also suffers from defects such as ferromagnetic saturation and ferromagnetic resonance, which seriously restrict the reliability and accuracy of synchronous phasor measurement in new power systems.

[0004] To address this, a current synchronization phasor sensing method based on magnetoresistive chips, which does not require direct electrical contact, offers a solution. However, in such methods, most existing specific measurement schemes require pre-calibration before measurement; in calibration-free measurement schemes, a specific spatial relationship needs to be maintained between the magnetoresistive chip and the circuit under test, and the process of solving for the amplitude of the measured current phasor is complex and difficult to adapt to actual measurement needs. Summary of the Invention

[0005] The purpose of this invention is to provide a method and device for rapid synchronous phasor sensing of single-phase current in power transmission and distribution lines, which solves the problems of poor installation convenience and complex calculation process of existing current phasor sensing methods.

[0006] To achieve the above objectives, the present invention provides a method for rapid phasor sensing of single-phase current synchronization in power system transmission and distribution lines, comprising the following steps:

[0007] S1. Construct a current sensing probe using a TMR chip and measure the spacing between the chips.

[0008] S2. Place the printed circuit board carrying the current sensing probe at the line to be tested, and collect the instantaneous output voltage values ​​of each TMR chip through the sampling circuit after synchronous timing.

[0009] S3. Calculate the phase of the current phasor to be measured based on the instantaneous value of the output voltage of the TMR chip;

[0010] S4. Based on the instantaneous output voltage of the TMR chip and the spacing between each chip, solve the measurement equation set to obtain the phasor amplitude of the current to be measured; the combination of the phase of the current to be measured and the amplitude of the current to be measured forms the synchronous phasor measurement result of the current of the circuit under test.

[0011] Preferably, in S1, the current sensing probe includes three single-axis TMR chips distributed along the same straight line, the sensing direction of the TMR chips is along the same direction, and the straight line along which the spatial positions of the three TMR chips are located is parallel to the sensing direction.

[0012] Preferably, in S2, the straight line along which the spatial position of the TMR chip is located is out of plane with the part of the circuit under test. The spatial position of the current sensing probe remains fixed during the sensing process. The output voltage of the TMR chip collected by the sampling circuit after synchronous synchronization is proportional to the magnitude of the projection of the magnetic field strength vector at the chip location along the sensitive direction.

[0013] Preferably, in step S3, the phase of the current phasor to be measured is the average value of the phase of the output voltage of each TMR chip.

[0014] Preferably, in step S4, the calculation process of the amplitude of the phasor of the current to be measured includes the following steps:

[0015] S41. Calculate the effective value of the magnetic field strength sensed by each TMR chip based on the parameters of the current sensing probe.

[0016] S42. Based on the infinitely long straight conductor model and Ampere's circuital law, write the relationship between the magnetic field strength vector at the location of each TMR chip and the amplitude of the phasor of the current to be measured.

[0017] S43. Based on the spatial relationship of the TMR chips, list the relationship between the magnitude of the magnetic field strength sensed by each TMR chip and the amplitude of the current phasor to be measured.

[0018] S44. Substitute the effective value of the magnetic field strength sensed by each TMR chip and the spacing between each TMR chip into the relationship between the magnitude of the magnetic field strength sensed by each TMR chip and the amplitude of the current phasor to be measured in S43 to obtain the measurement equation set and solve for the amplitude of the current phasor to be measured.

[0019] Preferably, in step S41, the effective value of the magnetic field strength sensed by each TMR chip is:

[0020] ;

[0021] in, , , TMR chips A , B, C The measured effective value of the sensed magnetic field strength.k The sensitivity coefficient of the TMR chip. Provide the power supply voltage for the TMR chip. U oA , U oB , U oC TMR chips A , B, C The instantaneous value of the output voltage.

[0022] Preferably, in step S42, the relationship between the magnetic field strength vector at the location of each TMR chip and the amplitude of the phasor of the current to be measured is as follows:

[0023] ;

[0024] in, , and These are the magnetic field strength vectors at the locations of TMR chips A, B, and C, respectively. , and These represent the magnitudes of the magnetic field strength at locations A, B, and C of the TMR chip, respectively. , , These represent the directions of the magnetic field strength at locations A, B, and C of the TMR chips, respectively, and the coordinates of locations A, B, and C are as follows: P A ( x A , 0, 0) P B ( x B , y B , z B ), P C ( x C , y C , z C ), I The amplitude of the current phasor to be measured.

[0025] Preferably, in step S43, the relationship between the magnitude of the magnetic field strength sensed by each TMR chip and the amplitude of the phasor of the current to be measured is as follows:

[0026] ;

[0027] in, H A ,H B , H C TMR chips A , B, C The magnitude of the magnetic field strength being sensed. d 1 is a TMR chip A With TMR chip B The distance between them; d 2 is a TMR chip A With TMR chip C The distance between them.

[0028] Preferably, in step S44, the expression for the amplitude of the phasor of the current to be measured is:

[0029] ;

[0030] in, For TMR chips A With TMR chip B The measured distance between them, For TMR chips A With TMR chip C The measured distance between them.

[0031] The sensing device used in the above-mentioned method for fast phasor synchronization of single-phase current in power transmission and distribution lines includes:

[0032] The current sensing probe consists of three linearly arranged single-axis TMR chips, used to sense the magnitude of the projection of the magnetic field strength vector along the sensitive direction at three locations of the circuit under test.

[0033] The voltage sampling unit, connected to the current sensing probe, is used to synchronously sample the analog voltage signal output by the TMR chip and convert it into a digital voltage signal.

[0034] The host computer communicates with the voltage sampling unit to receive digital voltage signals and calculate the synchronous phasor of the current of the line under test by combining the chip spacing of the current sensing probe.

[0035] A DC power supply is connected to the current sensing probe, voltage sampling unit, and host computer to provide a stable DC power supply.

[0036] The advantages and positive effects of the single-phase current synchronization phasor fast sensing method and device for power system transmission and distribution lines described in this invention are as follows:

[0037] 1. This invention utilizes three TMR chips to form a current sensing probe. When performing current measurement, the requirements for the relative spatial position between the probe and the circuit under test are relaxed. Current sensing can be performed in almost any state, which is suitable for complex field measurement environments. The installation and operation of the measuring device are convenient.

[0038] 2. This invention does not require a complex numerical iterative solution process when obtaining the current to be measured. It can directly analyze and solve the amplitude of the current phasor of the line under test. It has low requirements for the computing performance of hardware equipment, can realize rapid sensing of current information, and is suitable for application scenarios such as power transmission and distribution lines and distributed power clusters. It is easy to operate and use.

[0039] 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

[0040] Figure 1 This is a flowchart of the sensing method according to an embodiment of the present invention;

[0041] Figure 2 This is a schematic diagram of the current sensing probe structure according to an embodiment of the present invention;

[0042] Figure 3 This is a schematic diagram of the sensing device structure according to an embodiment of the present invention;

[0043] Figure 4 This is a schematic diagram of an experimental test scenario according to an embodiment of the present invention;

[0044] Figure 5 This is a schematic diagram showing partial details of the current sensing probe according to an embodiment of the present invention;

[0045] Figure 6 This is a partial view of the probe output voltage waveform according to an embodiment of the present invention;

[0046] Figure 7 The waveform diagrams for measuring the amplitude and phase of the current under test are shown in this embodiment of the invention.

[0047] Figure 8 The following are waveforms of the measured current amplitude and phase under different current amplitudes according to an embodiment of the present invention;

[0048] Figure 9 The waveforms of the measured current amplitude and phase under different current alternation frequencies are shown in the embodiments of the present invention. Detailed Implementation

[0049] 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.

[0050] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0051] like Figure 1 As shown, a method for rapid phasor sensing of single-phase current synchronization in power system transmission and distribution lines includes the following steps:

[0052] S1. Use TMR chips to construct a current sensing probe and measure the spacing between each chip.

[0053] The current sensing probe includes three single-axis TMR chips distributed along the same straight line. The sensing direction of the TMR chips is in the same direction, and the straight line along which the spatial positions of the three TMR chips are located is parallel to the sensing direction.

[0054] S2. Place the printed circuit board carrying the current sensing probe at the line to be tested, and collect the instantaneous output voltage values ​​of each TMR chip through the sampling circuit after synchronous timing.

[0055] For the circuit under test, its long, straight section should be selected, with no obvious bends. The straight line along which the TMR chip is positioned should be out of plane with the section of the circuit under test. The spatial position of the current sensing probe should remain fixed during sensing. Under these conditions, the current sensing probe can be placed at any position around the circuit under test. The output voltage of the TMR chip acquired by the sampling circuit after synchronization is proportional to the magnitude of the projection of the magnetic field strength vector at the chip's location along the sensitive direction.

[0056] S3. Calculate the phase of the current phasor to be measured based on the instantaneous value of the output voltage of the TMR chip.

[0057] The phase of the current phasor to be measured is calculated as follows: the phase of the output voltage of each TMR chip is calculated based on the sampling data of the output voltage of the TMR chip, and the average value of the phase calculation results of the three TMR chips is taken as the measurement result of the phase of the current phasor to be measured.

[0058] S4. Based on the instantaneous output voltage of the TMR chip and the spacing between each chip, solve the measurement equation set to obtain the phasor amplitude of the current to be measured; the combination of the phase of the current to be measured and the amplitude of the current to be measured forms the synchronous phasor measurement result of the current of the circuit under test.

[0059] The calculation process for the amplitude of the phasor of the current to be measured includes the following steps:

[0060] S41. Calculate the effective value of the magnetic field strength sensed by each TMR chip based on the parameters of the current sensing probe.

[0061] The effective value of the output voltage of each TMR chip is multiplied sequentially by the acquired chip sensitivity coefficient and the chip supply voltage to obtain the measured effective value of the magnetic field strength sensed by each TMR chip. The effective values ​​of the magnetic field strength sensed by each TMR chip are:

[0062] ;

[0063] in, , , TMR chips A , B, C The measured effective value of the sensed magnetic field strength. k The sensitivity coefficient of the TMR chip. Provide the power supply voltage for the TMR chip. U oA , U oB , U oC TMR chips A , B, C The instantaneous value of the output voltage.

[0064] S42. Based on the infinitely long straight conductor model and Ampere's circuital law, write the relationship between the magnetic field strength vector at the location of each TMR chip and the amplitude of the phasor of the current to be measured.

[0065] According to Ampere's circuital law, when integrating along a circular path perpendicular to the circuit under test, the magnitude of the phasor of the current under test and the magnitude of the magnetic field strength at the location of each single-axis TMR chip in the current sensing probe have the following relationship:

[0066] ;

[0067] Where I is the amplitude of the current phasor to be measured. , and These represent the distances between each single-axis TMR chip and the circuit under test. , and These represent the magnitude of the magnetic field strength at the location of each single-axis TMR chip. It is the infinitesimal vector of the integration path.

[0068] The direction of the magnetic field strength at the location of each single-axis TMR chip can be determined using the Biot-Saffar theorem:

[0069] ;

[0070] in, The current direction reference vector, , and These are the coordinate vectors of TMR chips A, B, and C, respectively. For example... Figure 2 As shown, the coordinates of the three TMR chips A, B, and C in the current sensing probe are as follows: P A ( x A , 0, 0) P B ( x B , y B , z B ), P C ( x C , y C , z C ).

[0071] Based on the magnitude of the magnetic field strength at the location of each single-axis TMR chip, the magnetic field strength vector at each TMR chip location is:

[0072] .

[0073] in, , and TMR chips A , B, C The magnetic field strength vector at the location.

[0074] S43. Based on the spatial relationship of the TMR chips, list the relationship between the magnitude of the magnetic field strength sensed by each TMR chip and the amplitude of the current phasor to be measured.

[0075] The theoretical expression for the magnitude of the magnetic field strength projected along the sensing direction at the location of each TMR chip, that is, the magnitude of the magnetic field strength sensed by each TMR chip, is as follows:

[0076] ;

[0077] in, d 1 is a TMR chip A With TMR chip B The distance between them d 2 is a TMR chip A With TMR chip CDistance between, sensitive direction .

[0078] Since the three TMR chips are arranged in a straight line in space, Therefore, there is ,and .

[0079] The relationship between the magnitude of the magnetic field strength sensed by each TMR chip and the amplitude of the phasor of the current to be measured is as follows:

[0080] ;

[0081] in, H A , H B , H C TMR chips A , B, C The magnitude of the magnetic field strength being sensed.

[0082] S44. Substitute the effective value of the magnetic field strength sensed by each TMR chip and the spacing between each TMR chip into the relationship between the magnitude of the magnetic field strength sensed by each TMR chip and the amplitude of the current phasor to be measured in S43 to obtain the measurement equation set and solve for the amplitude of the current phasor to be measured.

[0083] make as well as To reduce the number of unknown variables, the following theoretical relationship exists between the magnitude of the magnetic field strength sensed by each TMR chip and the amplitude of the phasor of the current to be measured:

[0084] ;

[0085] Substitute the TMR chip described in S2 into the above system of equations. A , B , C The measured value of the effective value of the sensed magnetic field strength , , and the measured values ​​of the inter-chip spacing described in S1 and The measurement results of the phasor amplitude of the current in the circuit under test are obtained by solving the problem.

[0086] .

[0087] The final synchronous phasor measurement result of the circuit under test is obtained by combining the current phasor phase measurement result and the current phasor amplitude measurement result.

[0088] like Figure 3As shown, a sensing device for a fast phasor sensing method for single-phase current synchronization in power system transmission and distribution lines includes:

[0089] The current sensing probe consists of three linearly arranged single-axis TMR chips, used to sense the magnitude of the projection of the magnetic field strength vector along the sensitive direction at three locations of the circuit under test.

[0090] The voltage sampling unit, connected to the current sensing probe, is used to synchronously sample the analog voltage signal output by the TMR chip and convert it into a digital voltage signal.

[0091] The host computer communicates with the voltage sampling unit to receive digital voltage signals and calculate the synchronous phasor of the current of the line under test by combining the chip spacing of the current sensing probe.

[0092] A DC power supply is connected to the current sensing probe, voltage sampling unit, and host computer to provide a stable DC power supply.

[0093] To further verify the measurement accuracy of this sensing method, experimental tests were conducted on this method under different measured current amplitudes and frequencies.

[0094] like Figure 4 The diagram shows the experimental test scenario. The current-carrying conductor under test is supported by an insulator and suspended above the ground. The current under test is generated by the OMICRON-CMC 256plus, and the voltage sampling unit is the NI cRIO 9039.

[0095] Figure 5 This is a partial schematic diagram of a current sensing probe equipped with linearly arranged TMR chips. The spacing between chips A and B, and between B and C, is 10mm. The backup power supply is used to power the chips when there is no external DC power supply.

[0096] The current to be measured is selected as At this time, the probe output voltage waveform is locally as follows: Figure 6 As shown in the figure, all voltage waveforms maintain the same phase. The closer the chip is to the conductor under test, the higher the output voltage amplitude. The output voltage data within 20 seconds after synchronization is used, and the calculated amplitude of the measured current is compared with the phase measurement waveform results as shown in the figure. Figure 7 As shown. The amplitude measurement error can be kept within ±3%, and the phase calculation error can be kept within ±1.5°.

[0097] Figure 8The table shows the measurement results under different current amplitudes. In this experiment, the applied AC frequency was set to 50Hz. The current amplitude varied from 10A to 36A, with intervals of 2A. To ensure measurement accuracy, a 20-second time window was used to average the current amplitude, and the result was used as the amplitude measurement value for each current level. Simultaneously, the phase of the output voltage of each chip was averaged using the same time window to obtain the phase measurement value. For detailed amplitude and phase measurement results, please refer to [link to relevant documentation]. Figure 8 Experimental data show that the overall measurement error of amplitude is controlled within ±2%, while the measurement error of phase remains within ±1°.

[0098] Figure 9 The table shows the measurement results under different alternating current frequencies. In this test, the amplitude of the alternating current was set to 10A, and the frequency range covered 50Hz to 550Hz, with frequency changes adjusted gradually at 50Hz intervals. A 20-second time window was used, and the average amplitude within this time range was calculated as the current amplitude measurement result at each frequency point. Simultaneously, the phase information of the current under test was determined by the average phase of the output voltage of each chip within the same time window to ensure the stability and accuracy of the measurement. The test results show that the overall error of the amplitude measurement was controlled within ±2.5%, while the error of the phase measurement remained within ±1°. This demonstrates the performance stability of the invention under different frequency conditions. The above results indicate that the measurement method described in this invention has high accuracy and stability and can meet the requirements for current phasor parameter measurement.

[0099] Therefore, the method and device for rapid synchronous phasor sensing of single-phase current in power transmission and distribution lines described in this invention can solve the problems of poor installation convenience and complex calculation process of existing current phasor sensing methods.

[0100] 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 rapid phasor sensing of single-phase current synchronization in power system transmission and distribution lines, characterized in that, Includes the following steps: S1. Construct a current sensing probe using a TMR chip and measure the spacing between the chips. S2. Place the printed circuit board carrying the current sensing probe at the line to be tested, and collect the instantaneous output voltage values ​​of each TMR chip through the sampling circuit after synchronous timing. S3. Calculate the phase of the current phasor to be measured based on the instantaneous value of the output voltage of the TMR chip; S4. Based on the instantaneous output voltage of the TMR chip and the spacing between each chip, solve the measurement equation set to obtain the amplitude of the phasor of the current to be measured. The combination of the phase and amplitude of the phasor of the current under test forms the synchronous phasor measurement result of the current of the line under test. In step S4, the calculation process of the amplitude of the phasor of the current to be measured includes the following steps: S41. Calculate the effective value of the magnetic field strength sensed by each TMR chip based on the parameters of the current sensing probe. S42. Based on the infinitely long straight conductor model and Ampere's circuital law, write the relationship between the magnetic field strength vector at the location of each TMR chip and the amplitude of the phasor of the current to be measured. S43. Based on the spatial relationship of the TMR chips, list the relationship between the magnitude of the magnetic field strength sensed by each TMR chip and the amplitude of the current phasor to be measured. S44. Substitute the effective value of the magnetic field strength sensed by each TMR chip and the spacing between each TMR chip into the relationship between the magnitude of the magnetic field strength sensed by each TMR chip and the amplitude of the current phasor to be measured in S43 to obtain the measurement equation set and solve for the amplitude of the current phasor to be measured. In S44, the expression for the amplitude of the phasor of the current to be measured is: ； in, , , TMR chips A , B, C The measured effective value of the sensed magnetic field strength. For TMR chips A With TMR chip B The measured distance between them, For TMR chips A With TMR chip C The measured distance between them.

2. The method for rapid phasor synchronization of single-phase current in power system transmission and distribution lines according to claim 1, characterized in that: In S1, the current sensing probe includes three single-axis TMR chips distributed along the same straight line. The sensing direction of the TMR chips is along the same direction, and the straight line along which the spatial positions of the three TMR chips are located is parallel to the sensing direction.

3. The method for rapid phasor synchronization of single-phase current in power system transmission and distribution lines according to claim 2, characterized in that: In S2, the straight line along which the spatial position of the TMR chip is located is out of plane with the part of the circuit under test. The spatial position of the current sensing probe remains fixed during the sensing process. The output voltage of the TMR chip acquired by the sampling circuit after synchronous synchronization is proportional to the projection of the magnetic field strength vector at the chip location along the sensitive direction.

4. The method for rapid phasor sensing of single-phase current synchronization in power system transmission and distribution lines according to claim 3, characterized in that: In S3, the phase of the current phasor to be measured is the average value of the output voltage phase of each TMR chip.

5. The method for rapid phasor sensing of single-phase current synchronization in power system transmission and distribution lines according to claim 4, characterized in that: In step S41, the effective value of the magnetic field strength sensed by each TMR chip is: ； in, , , TMR chips A , B, C The measured effective value of the sensed magnetic field strength. k The sensitivity coefficient of the TMR chip. Provide the power supply voltage for the TMR chip. U oA , U oB , U oC TMR chips A , B, C The instantaneous value of the output voltage.

6. The method for rapid phasor sensing of single-phase current synchronization in power system transmission and distribution lines according to claim 5, characterized in that: In S42, the relationship between the magnetic field strength vector at the location of each TMR chip and the amplitude of the phasor of the current to be measured is as follows: ； in, , and These are the magnetic field strength vectors at the locations of TMR chips A, B, and C, respectively. , and These represent the magnitudes of the magnetic field strength at locations A, B, and C of the TMR chip, respectively. , , These represent the directions of the magnetic field strength at locations A, B, and C of the TMR chips, respectively, and the coordinates of locations A, B, and C are as follows: P A ( x A , 0, 0) P B ( x B , y B , z B ), P C ( x C , y C , z C ), I The amplitude of the current phasor to be measured.

7. A method for rapid phasor sensing of single-phase current synchronization in power system transmission and distribution lines according to claim 6, characterized in that: In step S43, the relationship between the magnitude of the magnetic field strength sensed by each TMR chip and the amplitude of the current phasor to be measured is as follows: ； in, H A , H B , H C TMR chips A , B, C The magnitude of the magnetic field strength being sensed. d 1 is a TMR chip A With TMR chip B The distance between them; d 2 is a TMR chip A With TMR chip C The distance between them.

8. A sensing device for the fast phasor synchronization sensing method for single-phase current in power system transmission and distribution lines as described in claim 7, characterized in that, include: The current sensing probe consists of three linearly arranged single-axis TMR chips, used to sense the magnitude of the projection of the magnetic field strength vector along the sensitive direction at three locations of the circuit under test. The voltage sampling unit, connected to the current sensing probe, is used to synchronously sample the analog voltage signal output by the TMR chip and convert it into a digital voltage signal. The host computer communicates with the voltage sampling unit to receive digital voltage signals and calculate the synchronous phasor of the current of the line under test by combining the chip spacing of the current sensing probe. A DC power supply is connected to the current sensing probe, voltage sampling unit, and host computer to provide a stable DC power supply.

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