Three-phase voltage phase detection method, device and non-volatile storage medium

Abstract

The application discloses a three-phase voltage phase detection method, device and nonvolatile storage medium. The method comprises the following steps: sensing the initial electric field intensity of a first phase, the initial electric field intensity of a second phase and the initial electric field intensity of a third phase through a plurality of double-layer electric field sensors arranged at a plurality of preset positions of a target cable; determining the voltage measurement value corresponding to each phase based on the initial electric field intensity of the first phase, the initial electric field intensity of the second phase and the initial electric field intensity of the third phase; and determining the actual voltage phase of the first phase, the actual voltage phase of the second phase and the actual voltage phase of the third phase based on the coupling relationship among the first phase, the second phase and the third phase through the voltage measurement value of the first phase, the voltage measurement value of the second phase and the voltage measurement value of the third phase. The application solves the technical problem that the reference voltage phase measurement is inaccurate due to the mutual coupling interference of three-phase electric fields and the insufficient precision of a traditional signal processing method.

Description

Technical Field

[0001] This invention relates to the field of three-phase voltage phase detection technology, and more specifically, to a three-phase voltage phase detection method, apparatus, and non-volatile storage medium. Background Technology

[0002] Power cables are critical equipment for power grid transmission, and their insulation condition directly affects the safe operation of the system. The dielectric loss factor (tanδ) is a core parameter for assessing the aging and defects of the main insulation of cables, and its accurate measurement depends on the high-precision acquisition of the reference voltage phase. Traditional methods often obtain the reference signal through bus voltage transformers (PTs), but this method requires temporary connection of devices to the high-voltage primary equipment, which poses significant risks such as damaging the sealing structure, causing malfunctions, and endangering power grid safety. Furthermore, it violates power operation regulations and is not feasible in engineering.

[0003] Therefore, non-contact electric field sensing technology has become a research hotspot. It indirectly obtains the voltage phase by sensing the power frequency electric field around the cable terminal, offering advantages such as safety and convenience. However, existing electric field sensors mostly adopt a single-layer electrode structure, which is susceptible to interference from the coupling of adjacent phase electric fields. Although some schemes use a coaxial structure, they lack effective shielding design, and the electrode geometry parameters rely on experience without systematic optimization. In addition, signal processing generally relies on conventional FFT, which makes it difficult to suppress spectral leakage and picket fence effects caused by non-integer period sampling, resulting in insufficient phase measurement accuracy and failing to meet the requirements for high-precision tanδ detection.

[0004] There is currently no effective solution to the above problems. Summary of the Invention

[0005] This invention provides a three-phase voltage phase detection method, apparatus, and non-volatile storage medium to at least solve the technical problem of inaccurate reference voltage phase measurement caused by mutual coupling interference of three-phase electric fields and insufficient accuracy of traditional signal processing methods.

[0006] According to one aspect of the present invention, a three-phase voltage phase detection method is provided, comprising: sensing the initial electric field strength of a first phase, the initial electric field strength of a second phase, and the initial electric field strength of a third phase using a plurality of double-layer electric field sensors respectively disposed at a plurality of preset positions on a target cable, wherein the double-layer electric field sensor includes a first layer electrode and a second layer electrode, the first layer electrode is grounded through a grounding wire, the second layer electrode is used to sense the initial electric field strength, and the axial height of the first layer electrode is greater than the axial height of the second layer electrode; determining the voltage measurement values ​​of the first phase, the second phase, and the third phase respectively based on the initial electric field strength of the first phase, the second phase, and the third phase; and determining the actual voltage phase of the first phase, the second phase, and the third phase based on the voltage measurement values ​​of the first phase, the second phase, and the third phase, through the coupling relationship between the first phase, the second phase, and the third phase.

[0007] Optionally, the multiple preset positions include a first preset point in an annular space of the upper-middle region of the first corresponding cable terminal tail pipe and a preset distance from the surface of the tail pipe in the radial direction, a second preset point in an annular space of the upper-middle region of the second corresponding cable terminal tail pipe and a preset distance from the surface of the tail pipe in the radial direction, and a third preset point in an annular space of the upper-middle region of the third corresponding cable terminal tail pipe and a preset distance from the surface of the tail pipe in the radial direction.

[0008] Optionally, based on the initial electric field strength of the first phase, the initial electric field strength of the second phase, and the initial electric field strength of the third phase, the voltage measurement values ​​of the first phase, the second phase, and the third phase are determined, including: superimposing the initial electric field strength with the interference component attenuated by the first layer electrode through the coupling relationship between the first phase and the corresponding second layer electrode, the coupling relationship between the second phase and the corresponding second layer electrode, and the coupling relationship between the third phase and the corresponding second layer electrode to obtain the induced voltage signal of the first phase, the induced voltage signal of the second phase, and the induced voltage signal of the third phase; and respectively processing the induced voltage signal of the first phase, the induced voltage signal of the second phase, and the induced voltage signal of the third phase. The analog voltage signals of the first phase, second phase, and third phase are obtained through amplification and filtering. Analog-to-digital conversion is then performed on these signals to obtain digital voltage signals for the first, second, and third phases, respectively. Based on Fourier transform, the fundamental voltage components of the first, second, and third phases are extracted from these signals and used as the measured voltage values ​​for the first, second, and third phases, respectively.

[0009] Optionally, based on the voltage measurements of the first phase, the second phase, and the third phase, the actual voltage phases of the first, second, and third phases are determined through the coupling relationship between the first, second, and third phases. This includes: constructing an initial coupling model between the voltage measurements and the actual voltage values ​​through the coupling relationship between the first, second, and third phases; converting the initial coupling model into an equivalent coupling model based on the symmetry relationship between multiple preset positions; decomposing the voltage measurements of the first, second, and third phases in the complex domain based on the equivalent coupling model to obtain a system of equations containing multiple unknowns, including a first coupling coefficient, a second coupling coefficient, a third coupling coefficient, the real part of the actual voltage value of the first phase, and the imaginary part of the actual voltage value of the first phase; and solving the system of equations to obtain the actual voltage phases of the first, second, and third phases, wherein the tangent of the actual voltage phase of the first phase is the ratio of the imaginary part to the real part of the actual voltage value of the first phase.

[0010] Alternatively, the mathematical expression for the equivalent coupling model is as follows:

[0011]

[0012] in, This is the voltage measurement value for the first phase. This is the voltage measurement value for the second phase. This is the voltage measurement value for the third phase. This is the actual voltage value of the first phase. The first coupling coefficient, The second coupling coefficient, The third coupling coefficient, This is the conversion coefficient between the first phase, the second phase, and the third phase.

[0013] Optionally, it also includes: using the actual voltage phase of the first phase, the actual voltage phase of the second phase, and the actual voltage phase of the third phase as reference values ​​to determine the insulation dielectric loss coefficient of the target cable.

[0014] According to another aspect of the present invention, a three-phase voltage phase detection device is also provided, comprising: a sensing module, configured to sense the initial electric field strength of a first phase, the initial electric field strength of a second phase, and the initial electric field strength of a third phase using a plurality of double-layer electric field sensors respectively disposed at a plurality of preset positions on a target cable, wherein the double-layer electric field sensors include a first layer electrode and a second layer electrode, the first layer electrode being grounded through a grounding wire, the second layer electrode being used to sense the initial electric field strength, and the axial height of the first layer electrode being greater than the axial height of the second layer electrode; a first determining module, configured to determine the voltage measurement values ​​of the first phase, the second phase, and the third phase respectively based on the initial electric field strength of the first phase, the initial electric field strength of the second phase, and the initial electric field strength of the third phase; and a second determining module, configured to determine the actual voltage phase of the first phase, the actual voltage phase of the second phase, and the actual voltage phase of the third phase based on the voltage measurement values ​​of the first phase, the second phase, and the third phase, through the coupling relationship between the first phase, the second phase, and the third phase.

[0015] According to another aspect of the present invention, a non-volatile storage medium is also provided, the non-volatile storage medium including a stored program, wherein, when the program is running, the device where the non-volatile storage medium is located is controlled to execute any of the three-phase voltage phase detection methods described above.

[0016] According to another aspect of the present invention, a computer device is also provided, the computer device including a processor, the processor being configured to run a program, wherein the program executes any of the three-phase voltage phase detection methods described above.

[0017] According to another aspect of the present invention, a computer program product is also provided, including a computer program that, when executed by a processor, implements any one of the three-phase voltage phase detection methods described above.

[0018] In this embodiment of the invention, a three-phase voltage phase detection method is employed. Multiple double-layer electric field sensors, each positioned at a predetermined location on the target cable, sense the initial electric field strength of the first phase, the initial electric field strength of the second phase, and the initial electric field strength of the third phase. Each double-layer electric field sensor includes a first layer electrode and a second layer electrode. The first layer electrode is grounded via a grounding wire, and the second layer electrode is used to sense the initial electric field strength. The axial height of the first layer electrode is greater than the axial height of the second layer electrode. Based on the initial electric field strengths of the first, second, and third phases, the measured voltage values ​​of the first phase and the second phase are determined, respectively. The measured values ​​of the first, second, and third phases are used to determine the actual phases of the first, second, and third phases of the voltage, based on the voltage measurements of the first, second, and third phases and the coupling relationship between them. This achieves the goal of accurately obtaining the true phase of the cable phase voltage without intruding into the high-voltage primary system, thus realizing the technical effect of high-precision, non-contact, and anti-interference three-phase voltage phase collaborative calculation. This solves the technical problem of inaccurate reference voltage phase measurement caused by mutual coupling interference of the three-phase electric fields and insufficient accuracy of traditional signal processing methods. Attached Figure Description

[0019] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, illustrate exemplary embodiments of the invention and, together with their description, serve to explain the invention and do not constitute an undue limitation thereof. In the drawings:

[0020] Figure 1 A hardware block diagram of a computer terminal for implementing a three-phase voltage phase detection method is shown.

[0021] Figure 2 This is a schematic flowchart of a three-phase voltage phase detection method provided according to an embodiment of the present invention;

[0022] Figure 3 This is a schematic diagram of a cross-sectional structure of an electric field sensor according to an optional embodiment of the present invention;

[0023] Figure 4 This is a schematic diagram of the electric field distribution cloud map near a 110kV GIS cable terminal obtained by electromagnetic simulation according to an optional embodiment of the present invention;

[0024] Figure 5 This is a schematic flowchart of a high-precision voltage phase detection method for live measurement of dielectric loss in cable main insulation provided by an optional embodiment of the present invention;

[0025] Figure 6This is a schematic diagram comparing the amplitude-frequency response curves of the Hanning-4-term 5th-order Nuttall hybrid convolution window and the conventional Hanning window and 4-term 5th-order Nuttall window according to an optional embodiment of the present invention.

[0026] Figure 7 This is a flowchart of a three-phase signal decoupling algorithm based on complex decomposition and algebraic constraints provided by an optional embodiment of the present invention;

[0027] Figure 8 This is a structural block diagram of a three-phase voltage phase detection device provided according to an optional embodiment of the present invention.

[0028] Figure label:

[0029] 1. Inner measuring electrode; 2. Outer shielding electrode; 3. Solid insulating medium; 4. Terminal; 5. Another terminal. Detailed Implementation

[0030] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0031] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0032] According to an embodiment of the present invention, a three-phase voltage phase detection method is provided. It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions. Furthermore, although a logical order is shown in the flowchart, in some cases, the steps shown or described may be executed in a different order than that shown here.

[0033] The method embodiment provided in Embodiment 1 of this application can be executed on a mobile terminal, computer terminal, or similar computing device. Figure 1 A hardware block diagram of a computer terminal for implementing a three-phase voltage phase detection method is shown. Figure 1 As shown, the computer terminal 10 may include one or more processors (shown as 102a, 102b, ..., 102n in the figure) (the processor may include, but is not limited to, a microprocessor MCU or a programmable logic device FPGA, etc.) and a memory 104 for storing data. In addition, it may also include: a display, an input / output interface (I / O interface), a universal serial bus (USB) port (which may be included as one of the ports of a BUS bus), a network interface, a power supply, and / or a camera. Those skilled in the art will understand that... Figure 1 The structure shown is for illustrative purposes only and does not limit the structure of the aforementioned electronic device. For example, computer terminal 10 may also include... Figure 1 The more or fewer components shown, or having the same Figure 1 The different configurations shown.

[0034] It should be noted that the aforementioned one or more processors and / or other data processing circuits are generally referred to herein as "data processing circuits". These data processing circuits may be embodied, in whole or in part, in software, hardware, firmware, or any other combination thereof. Furthermore, the data processing circuits may be a single, independent processing module, or may be integrated, in whole or in part, into any other element within the computer terminal 10. As involved in the embodiments of this application, the data processing circuits serve as a processor control mechanism (e.g., selection of a variable resistor termination path connected to an interface).

[0035] The memory 104 can be used to store software programs and modules for application software, such as the program instructions / data storage device corresponding to the three-phase voltage phase detection method in this embodiment of the invention. The processor executes various functional applications and data processing by running the software programs and modules stored in the memory 104, thereby realizing the three-phase voltage phase detection method of the aforementioned application program. The memory 104 may include high-speed random access memory, and may also include non-volatile memory, such as one or more magnetic storage devices, flash memory, or other non-volatile solid-state memory. In some instances, the memory 104 may further include memory remotely located relative to the processor, and these remote memories can be connected to the computer terminal 10 via a network. Examples of such networks include, but are not limited to, the Internet, corporate intranets, local area networks, mobile communication networks, and combinations thereof.

[0036] The display can be, for example, a touchscreen liquid crystal display (LCD) that allows the user to interact with the user interface of the computer terminal 10.

[0037] Figure 2 This is a schematic flowchart of a three-phase voltage phase detection method provided according to an embodiment of the present invention, as shown below. Figure 2 As shown, the method includes the following steps:

[0038] Step S201: Using multiple double-layer electric field sensors set at multiple preset positions on the target cable, the initial electric field strength of the first phase, the initial electric field strength of the second phase, and the initial electric field strength of the third phase are sensed. The double-layer electric field sensor includes a first layer electrode and a second layer electrode. The first layer electrode is grounded through a grounding wire, and the second layer electrode is used to sense the initial electric field strength. The axial height of the first layer electrode is greater than the axial height of the second layer electrode.

[0039] In this step, multiple double-layer electric field sensors are installed at multiple preset locations on the target cable to sense the initial electric field strength of the first phase (phase A), the initial electric field strength of the second phase (phase B), and the initial electric field strength of the third phase (phase C). Figure 3 This is a schematic diagram of a cross-sectional structure of an electric field sensor according to an optional embodiment of the present invention, as shown below. Figure 3 As shown, the dual-layer electric field sensor is the core sensing unit. Its structure consists of a second electrode (i.e., the inner measuring electrode) and a first electrode (i.e., the outer shielding electrode) coaxially nested together, with epoxy resin insulation filling the space between them. The inner measuring electrode 1, i.e., the second electrode, is made of brass and is cylindrical with an axial height of 80 mm, a wall thickness of 10 mm, and an inner diameter of 20 mm. The outer shielding electrode 2, i.e., the first electrode, is also made of brass and is cylindrical, coaxially and centered around the inner measuring electrode 1 with an axial height of 100 mm, a wall thickness of 30 mm, and an inner diameter of 60 mm. The solid insulating medium 3 fills the annular space between the inner measuring electrode 1 and the outer shielding electrode 2 and can be formed into an integral structure by vacuum casting and curing epoxy resin. Terminal 4 connects to a wire that leads the measurement signal from the inner measuring electrode 1 and sends it to the subsequent signal processing module. Another terminal 5 is installed on the outer wall of the outer shielding electrode and connects to a wire for grounding. The sensors are installed in the optimal coupling area (upper axial part, radial distance from the surface 10-40mm) on the outside of the tailpipe of the three-phase cable terminal to ensure maximum induced signal strength and minimum interference. This structure enables independent, non-contact, and safe sensing of the electric field of each phase, providing the original data foundation for subsequent analysis.

[0040] Step S202: Based on the initial electric field strength of the first phase, the initial electric field strength of the second phase, and the initial electric field strength of the third phase, determine the voltage measurement values ​​of the first phase, the second phase, and the third phase, respectively.

[0041] In this step, the induced voltage signal is first output from the original electric field signal sensed by the sensor, and then the induced voltage signal output by the sensor is conditioned and digitally processed. First, the weak induced signal is amplified without load by a high input impedance amplifier to avoid signal attenuation; then, it is filtered by a fourth-order Butterworth low-pass filter (composed of two cascaded second-order filters) to remove high-frequency noise and spatial electromagnetic interference, retaining the 50Hz power frequency fundamental component; the filtered analog signal is synchronously sampled by a high-precision data acquisition card and converted into a digital sequence. Subsequently, a Hanning-4 term fifth-order Nuttall hybrid convolution window function is applied to the discrete signals of each phase to suppress spectral leakage and picket fence effect caused by non-integer period sampling; then, the spectrum is obtained by Fast Fourier Transform (FFT), and the frequency shift and phase of the fundamental wave are accurately calculated using a dual-spectral-line interpolation correction algorithm, finally outputting the voltage measurement values ​​of each phase, that is, the three-phase complex voltage phasors (including amplitude and phase) initially extracted due to coupling interference.

[0042] Step S203: Based on the voltage measurement values ​​of the first phase, the second phase, and the third phase, determine the actual voltage phase of the first phase, the actual voltage phase of the second phase, and the actual voltage phase of the third phase through the coupling relationship between the first phase, the second phase, and the third phase.

[0043] In this step, three-phase complex domain algebraic decoupling is performed. Since structural shielding cannot completely eliminate interference from adjacent phases, residual coupling components remain in the measured voltage values ​​of each phase; for example, the measured value of phase A contains interference from phases B and C. Based on the symmetry of the three-phase voltages in the power system and the physical constraint that the vector sum is zero, a three-phase coupling model is established. Combining the coupling symmetry caused by the symmetrical arrangement of sensors, the complex equations are decomposed into real and imaginary parts, constructing an overdetermined real linear equation system with 6 equations and 5 unknowns. The constraint that the sum of the three-phase voltages is zero is introduced, and finally, the least squares method is used to solve the system, accurately deriving the true phase and amplitude of the three-phase voltages. This achieves mathematical isolation and compensation for residual coupling interference, thereby obtaining the actual value that truly reflects the voltage of the cable itself.

[0044] Through the above steps, the goal of accurately obtaining the true phase of the cable phase voltage without intruding into the high-voltage primary system is achieved. This realizes the technical effect of high-precision, non-contact, and anti-interference three-phase voltage phase collaborative calculation, and solves the technical problem of inaccurate reference voltage phase measurement caused by mutual coupling interference of three-phase electric fields and insufficient accuracy of traditional signal processing methods.

[0045] As an optional embodiment, the multiple preset positions include a first preset point in an annular space of the upper-middle region of the first corresponding cable terminal tail pipe and a preset distance from the surface of the tail pipe in the radial direction; a second preset point in an annular space of the upper-middle region of the second corresponding cable terminal tail pipe and a preset distance from the surface of the tail pipe in the radial direction; and a third preset point in an annular space of the upper-middle region of the third corresponding cable terminal tail pipe and a preset distance from the surface of the tail pipe in the radial direction.

[0046] Optionally, the aforementioned preset positions correspond to the optimal electric field coupling region of the three-phase cable terminal tail pipe, specifically: the first preset point is located in the axial upper-middle region of the first phase cable terminal tail pipe, within an annular space with a radial distance of 10 to 40 mm from the outer surface of the tail pipe; the second preset point is located in the axial upper-middle region of the second phase cable terminal tail pipe, within an annular space with a radial distance of 10 to 40 mm from the outer surface of the tail pipe; and the third preset point is located in the axial upper-middle region of the third phase cable terminal tail pipe, within an annular space with a radial distance of 10 to 40 mm from the outer surface of the tail pipe. Figure 4 This is a schematic diagram of the electric field distribution cloud map near a 110kV GIS cable terminal obtained through electromagnetic simulation, provided by an optional embodiment of the present invention. Figure 4 As shown in the figure, the purple and red areas represent the regions with the strongest electric field strength, which is the optimal installation location for the sensor. This location is situated within an annular space located in the upper-middle axial region of the cable terminal tailpipe of the phase being measured, and radially at a distance of 10–40 mm from the surface of the tailpipe. Installing the electric field sensor at this location ensures signal strength while reducing coupling interference from other phases.

[0047] As an optional embodiment, determining the voltage measurement values ​​of the first phase, the second phase, and the third phase based on the initial electric field strength of the first phase, the initial electric field strength of the second phase, and the initial electric field strength of the third phase includes: superimposing the initial electric field strength with the interference component attenuated by the first layer electrode through the coupling relationship between the first phase and the corresponding second layer electrode, the coupling relationship between the second phase and the corresponding second layer electrode, and the coupling relationship between the third phase and the corresponding second layer electrode to obtain the induced voltage signal of the first phase, the induced voltage signal of the second phase, and the induced voltage signal of the third phase; and respectively analyzing the induced voltage signal of the first phase, the induced voltage signal of the second phase, and the induced voltage signal of the third phase. The signals are amplified and filtered to obtain analog voltage signals for the first, second, and third phases. Analog-to-digital conversion is then performed on these signals to obtain digital voltage signals for the first, second, and third phases, respectively. Based on Fourier transform, the fundamental voltage components of the first, second, and third phases are extracted from these digital voltage signals and used as the measured voltage values ​​for the first, second, and third phases, respectively.

[0048] Optionally, Figure 5 This is a flowchart illustrating a high-precision voltage phase detection method for live measurement of dielectric loss in cable main insulation according to an optional embodiment of the present invention. Figure 5 As shown, to accurately extract the phase voltage measurements from the initial electric field strength sensed by the double-layer electric field sensor, the following signal processing flow can be adopted: Step 1: Sensor fabrication, installation, and system initialization. Fabricate a double-layer cylindrical electric field sensor and install it at the predetermined measurement positions outside the three-phase cable terminal tailpipe using a dedicated insulating bracket. Reliably ground the outer shielding electrode through the wiring port, and connect the inner measuring electrode through the wiring hole to output the induced signal to the signal processing unit. After the system is powered on, the host sends an initialization command. Step 2: Spatial electric field induction and signal coupling. Under normal operating conditions, an electric field is generated around the three-phase cable terminal tailpipe. This electric field is induced by the inner measuring electrode through the coupling capacitance between the phase to be measured and the measuring electrode plate, forming an induced voltage signal, which can be expressed as:

[0049]

[0050] Where k is the coupling coefficient, and E(t) is the electric field strength of the measured phase. Interference components attenuated by the outer shielding electrode The induced signal is transmitted to the subsequent signal processing unit via the output wire. Therefore, the second step converts the directly induced electric field signal into a voltage signal, with both signals in phase; the third step involves signal amplification and filtering. (Induced signals for each phase...) First, the signal enters a high input impedance amplifier (input impedance > 1GΩ), then passes through a fourth-order Butterworth low-pass filter composed of two cascaded second-order Butterworth low-pass filters. This filter removes high-frequency noise and spatial electromagnetic interference, retaining the 50Hz power frequency component, thus obtaining the processed voltage signal. Step 4: Data Acquisition and Transmission. The amplified and filtered analog signal... The data is directly fed into the data acquisition card, which then performs the digitization of the analog signal. The acquisition card connects to the host computer via a USB / Ethernet interface, transmitting the digitized waveform data to the host computer for further data processing and parameter extraction. The fifth step involves digital signal processing and voltage information extraction. After receiving the waveform data, the host computer processes the discrete sequence... Digital signal processing is performed. First, the signal is windowed using a Hanning-4-term 5th-order Nuttall hybrid convolution window. Then, a Fast Fourier Transform (FFT) is performed on the windowed signal to obtain the spectral sequence. The position of the spectral line corresponding to the fundamental wave is determined by searching for the maximum spectral amplitude. A dual-spectral-line interpolation correction algorithm is then used to accurately calculate the fundamental voltage information. Figure 6 This is a schematic diagram comparing the amplitude-frequency response curves of the Hanning-4-term 5th-order Nuttall hybrid convolution window and the conventional Hanning window and the 4-term 5th-order Nuttall window, as provided in an optional embodiment of the present invention. Figure 6 As shown, the hybrid convolution window combines the advantages of two window functions in the time domain through convolution operations, further optimizing the balance between main lobe energy concentration and side lobe attenuation performance. That is, while retaining the advantage of main lobe narrowing, the side lobe attenuation rate is also improved. Therefore, the above-mentioned Hanning-4 term 5th-order Nuttall hybrid convolution window function is selected to improve the FFT. Combined with the subsequent bispectral interpolation correction algorithm, the measurement accuracy of the phase of the three-phase cable terminal voltage is significantly improved in complex electromagnetic environments.

[0051] As an optional embodiment, based on the voltage measurements of the first phase, the second phase, and the third phase, the actual voltage phases of the first, second, and third phases are determined through the coupling relationships between the first, second, and third phases. This includes: constructing an initial coupling model between the voltage measurements and the actual voltage values ​​through the coupling relationships between the first, second, and third phases; converting the initial coupling model into an equivalent coupling model based on the symmetry relationships between multiple preset positions; and performing calculations in the complex domain based on the equivalent coupling model. The measured voltage values ​​of the first phase, the second phase, and the third phase are decomposed to obtain a system of equations containing multiple unknowns, including the first coupling coefficient, the second coupling coefficient, the third coupling coefficient, the real part of the actual voltage value of the first phase, and the imaginary part of the actual voltage value of the first phase. Solving the system of equations yields the actual voltage phases of the first phase, the second phase, and the third phase, where the tangent of the actual voltage phase of the first phase is the ratio of the imaginary part to the real part of the actual voltage value of the first phase.

[0052] Optionally, Figure 7 This is a flowchart of a three-phase signal decoupling algorithm based on complex decomposition and algebraic constraints provided by an optional embodiment of the present invention, as shown below. Figure 7 As shown, the three-phase voltage measurements are first obtained through signal and data processing using an electric field sensor, denoted as... , , The voltage signal is a measured value that includes coupling effects. Due to the influence of system structure and spatial relationship, there is a coupling relationship between the three-phase voltages, and the following coupling model is established:

[0053]

[0054] in, , and These are the measured three-phase voltage values; the actual three-phase voltage values ​​are... , and , Let be the coupling coefficient. Based on the symmetrical positioning, the coupling coefficient follows the following equation:

[0055]

[0056] Therefore, the coupling model can be equivalently transformed into:

[0057]

[0058] Subsequently, the measured voltage signal is represented in the complex domain, and its real and imaginary parts are decomposed as follows:

[0059]

[0060]

[0061]

[0062] Based on the above decomposition, the original coupling relationship can be transformed into a set of real algebraic equations, with 6 equations and 5 unknowns, namely... , , , , .Regulation: , which is the tangent of the actual phase of the voltage in phase A, is obtained by analytically solving the system of equations as follows:

[0063]

[0064] By substituting the known data, the tangent of the phase A voltage can be accurately obtained, and thus the phase A voltage can be calculated. Similarly, the phases of phases B and C can be calculated, achieving decoupling of the three-phase voltages. Based on the constraints introduced to determine the uniqueness of the solution, the equations are solved analytically to accurately obtain the phase information of the actual three-phase voltage signals after decoupling.

[0065] Compared with current technologies, the aforementioned method embodiments have the following advantages:

[0066] (1) Strong resistance to three-phase coupling interference: The present invention adopts a double-layer cylindrical coaxial electrode structure. The outer shielding electrode is grounded and its axial height is greater than that of the inner measuring electrode, forming an axial shielding extension, which can effectively attenuate electric field coupling interference from adjacent phases. Compared with the existing single-layer electrode or simple shielding structure, it significantly improves the signal-to-noise ratio of single-phase electric field measurement.

[0067] (2) Key dimensional parameters have been optimized through simulation, and the design basis is sufficient: This invention uses COMSOL electromagnetic field simulation to perform multi-objective optimization of key parameters such as the height ratio, radial spacing, and wall thickness of the outer shielding electrode and the inner measuring electrode, and gives specific quantitative ranges. The axial height (L_m) of the inner measuring electrode is less than the axial height (L_s) of the outer shielding electrode. L_m can be fixed at 80mm, which needs to meet the following: 1.125≤L_s / L_m≤1.5, forming an axial shielding section, and achieving the best balance between signal strength and anti-interference capability.

[0068] (3) Introducing a complex domain decoupling algorithm to eliminate residual coupling: In response to the residual coupling that still exists after hardware shielding, this invention adds a three-phase decoupling module after the signal processing module, introduces a decoupling algorithm, directly calculates the actual voltage phase from the three-phase measurement complex phasors, further separates the interference components, and effectively improves the phase extraction accuracy.

[0069] (4) High-precision digital signal processing to suppress spectral leakage and picket fence effect: The present invention uses Hanning-4 term 5th order Nuttall hybrid convolution window function to window the sampled signal, and combined with the dual spectral line interpolation correction algorithm, to greatly suppress spectral leakage and picket fence effect caused by non-integer period sampling, improve the accuracy of fundamental phase measurement, and meet the high-precision phase requirements of cable terminal live detection.

[0070] It should be noted that, for the sake of simplicity, the foregoing method embodiments are all described as a series of actions. However, those skilled in the art should understand that the present invention is not limited to the described order of actions, because according to the present invention, some steps can be performed in other orders or simultaneously. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are preferred embodiments, and the actions and modules involved are not necessarily essential to the present invention.

[0071] Through the above description of the embodiments, those skilled in the art can clearly understand that the three-phase voltage phase detection method according to the above embodiments can be implemented by means of software plus necessary general-purpose hardware platform. Of course, it can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) and includes several instructions to cause a terminal device (which may be a mobile phone, computer, server, or network device, etc.) to execute the methods described in the various embodiments of the present invention.

[0072] According to embodiments of the present invention, a three-phase voltage phase detection device for implementing the above-described three-phase voltage phase detection method is also provided. Figure 8 This is a structural block diagram of a three-phase voltage phase detection device provided according to an embodiment of the present invention, such as... Figure 8 As shown, the device includes: a sensing module 81, a first determining module 82, and a second determining module 83. The device will be described below.

[0073] The sensing module 81 is used to sense the initial electric field strength of the first phase, the initial electric field strength of the second phase, and the initial electric field strength of the third phase by means of multiple double-layer electric field sensors respectively set at multiple preset positions on the target cable. The double-layer electric field sensor includes a first layer electrode and a second layer electrode. The first layer electrode is grounded through a grounding wire, and the second layer electrode is used to sense the initial electric field strength. The axial height of the first layer electrode is greater than the axial height of the second layer electrode.

[0074] The first determining module 82, connected to the acquisition module 81, is used to determine the voltage measurement values ​​of the first phase, the second phase, and the third phase respectively based on the initial electric field strength of the first phase, the initial electric field strength of the second phase, and the initial electric field strength of the third phase.

[0075] The second determining module, connected to the first determining module 82, is used to determine the actual voltage phase of the first phase, the actual voltage phase of the second phase, and the actual voltage phase of the third phase based on the voltage measurement values ​​of the first phase, the second phase, and the third phase, through the coupling relationship between the first phase, the second phase, and the third phase.

[0076] It should be noted that the aforementioned sensing module 81, first determining module 82, and second determining module 83 correspond to steps S201 to S203 in the embodiments. Multiple modules implement the same instances and application scenarios as their corresponding steps, but are not limited to the content disclosed in the above embodiments. It should also be noted that the aforementioned modules, as part of the device, can run on the computer terminal 10 provided in the embodiments.

[0077] Embodiments of the present invention may provide a computer device. Optionally, in this embodiment, the computer device may be located in at least one of a plurality of network devices in a computer network. The computer device includes a memory and a processor.

[0078] The memory can be used to store software programs and modules, such as the program instructions / modules corresponding to the three-phase voltage phase detection method and device in this embodiment of the invention. The processor executes various functional applications and data processing by running the software programs and modules stored in the memory, thereby realizing the aforementioned three-phase voltage phase detection method. The memory may include high-speed random access memory, and may also include non-volatile memory, such as one or more magnetic storage devices, flash memory, or other non-volatile solid-state memory. In some instances, the memory may further include memory remotely located relative to the processor, and these remote memories can be connected to a computer terminal via a network. Examples of such networks include, but are not limited to, the Internet, corporate intranets, local area networks, mobile communication networks, and combinations thereof.

[0079] The processor can invoke information and application programs stored in the memory via a transmission device to execute the following steps: Sensing the initial electric field strength of the first phase, the initial electric field strength of the second phase, and the initial electric field strength of the third phase using multiple double-layer electric field sensors respectively set at multiple preset locations on the target cable. Each double-layer electric field sensor includes a first layer electrode and a second layer electrode. The first layer electrode is grounded via a grounding wire, and the second layer electrode is used to sense the initial electric field strength. The axial height of the first layer electrode is greater than the axial height of the second layer electrode. Based on the initial electric field strength of the first phase, the initial electric field strength of the second phase, and the initial electric field strength of the third phase, determining the voltage measurement values ​​of the first phase, the second phase, and the third phase, respectively. Based on the voltage measurement values ​​of the first phase, the second phase, and the third phase, determining the actual voltage phase of the first phase, the actual voltage phase of the second phase, and the actual voltage phase of the third phase through the coupling relationship between the first, second, and third phases.

[0080] Optionally, the processor may also execute program code for the following steps: multiple preset positions include a first preset point in an annular space of the upper-middle region of the first corresponding cable terminal tail pipe and a preset distance from the surface of the tail pipe in the radial direction, a second preset point in an annular space of the upper-middle region of the second corresponding cable terminal tail pipe and a preset distance from the surface of the tail pipe in the radial direction, and a third preset point in an annular space of the upper-middle region of the third corresponding cable terminal tail pipe and a preset distance from the surface of the tail pipe in the radial direction.

[0081] Optionally, the processor may also execute program code with the following steps: By using the coupling relationships between the first phase and the corresponding second layer electrode, the second phase and the corresponding second layer electrode, and the third phase and the corresponding second layer electrode, the initial electric field strength is superimposed with the interference component attenuated by the first layer electrode to obtain the induced voltage signal of the first phase, the induced voltage signal of the second phase, and the induced voltage signal of the third phase; the induced voltage signals of the first phase, the second phase, and the third phase are amplified and filtered respectively to obtain the analog voltage signal of the first phase, the induced voltage signal of the second phase, and the induced voltage signal of the third phase. The analog voltage signals of the first phase and the third phase are obtained. Analog-to-digital conversion is performed on the analog voltage signals of the first phase, the second phase, and the third phase respectively to obtain the digital voltage signals of the first phase, the second phase, and the third phase. Based on Fourier transform, the fundamental voltage components of the first phase, the second phase, and the third phase are extracted from the digital voltage signals of the first phase, the second phase, and the third phase respectively, and used as the voltage measurement values ​​of the first phase, the second phase, and the third phase.

[0082] Optionally, the processor may also execute program code with the following steps: constructing an initial coupling model between the voltage measurement value and the actual voltage value based on the coupling relationship between the first phase, the second phase, and the third phase; converting the initial coupling model into an equivalent coupling model based on the symmetry relationship between multiple preset positions; decomposing the voltage measurement values ​​of the first phase, the second phase, and the third phase in the complex domain based on the equivalent coupling model to obtain a system of equations containing multiple unknowns, wherein the multiple unknowns include the first coupling coefficient, the second coupling coefficient, the third coupling coefficient, the real part of the actual voltage value of the first phase, and the imaginary part of the actual voltage value of the first phase; solving the system of equations to obtain the actual voltage phase of the first phase, the actual voltage phase of the second phase, and the actual voltage phase of the third phase, wherein the tangent of the actual voltage phase of the first phase is the ratio of the imaginary part to the real part of the actual voltage value of the first phase.

[0083] Optionally, the processor described above can also execute program code with the following steps: The mathematical expression of the equivalent coupling model is as follows:

[0084] ,

[0085] in, This is the voltage measurement value for the first phase. This is the voltage measurement value for the second phase. This is the voltage measurement value for the third phase. This is the actual voltage value of the first phase. The first coupling coefficient, The second coupling coefficient, The third coupling coefficient, This is the conversion coefficient between the first phase, the second phase, and the third phase.

[0086] Optionally, the processor may also execute program code that performs the following steps: using the actual voltage phase of the first phase, the actual voltage phase of the second phase, and the actual voltage phase of the third phase as reference values ​​to determine the insulation dielectric loss coefficient of the target cable.

[0087] This invention provides a method for detecting the phase of a three-phase voltage. Multiple double-layer electric field sensors, each positioned at a predetermined location on a target cable, sense the initial electric field strength of the first phase, the second phase, and the third phase. Each double-layer electric field sensor includes a first electrode and a second electrode. The first electrode is grounded via a grounding wire, and the second electrode is used to sense the initial electric field strength. The axial height of the first electrode is greater than that of the second electrode. Based on the initial electric field strengths of the first, second, and third phases, the measured voltage values ​​of the first, second, and third phases are determined, respectively. Based on the voltage measurements of the first, second, and third phases, and through the coupling relationship between the first, second, and third phases, the actual phases of the voltage of the first, second, and third phases are determined. This achieves the goal of accurately obtaining the true phase of the cable phase voltage without intruding into the high-voltage primary system. This realizes the technical effect of high-precision, non-contact, and anti-interference three-phase voltage phase collaborative calculation, and solves the technical problem of inaccurate reference voltage phase measurement caused by mutual coupling interference of the three-phase electric fields and insufficient accuracy of traditional signal processing methods.

[0088] Those skilled in the art will understand that all or part of the steps in the various methods of the above embodiments can be implemented by a program instructing the hardware related to the terminal device. The program can be stored in a non-volatile storage medium, which may include: flash drive, read-only memory (ROM), random access memory (RAM), disk or optical disk, etc.

[0089] Embodiments of the present invention also provide a non-volatile storage medium. Optionally, in this embodiment, the non-volatile storage medium can be used to store the program code executed by the three-phase voltage phase detection method provided in the above embodiments.

[0090] Optionally, in this embodiment, the non-volatile storage medium may be located in any computer terminal in a group of computer terminals in a computer network, or in any mobile terminal in a group of mobile terminals.

[0091] Optionally, in this embodiment, the non-volatile storage medium is configured to store program code for performing the following steps: sensing the initial electric field strength of the first phase, the initial electric field strength of the second phase, and the initial electric field strength of the third phase using multiple double-layer electric field sensors respectively set at multiple preset positions on the target cable, wherein the double-layer electric field sensor includes a first layer electrode and a second layer electrode, the first layer electrode is grounded through a grounding wire, the second layer electrode is used to sense the initial electric field strength, and the axial height of the first layer electrode is greater than the axial height of the second layer electrode; determining the voltage measurement values ​​of the first phase, the second phase, and the third phase respectively based on the initial electric field strength of the first phase, the second phase, and the third phase; and determining the actual voltage phase of the first phase, the second phase, and the third phase based on the voltage measurement values ​​of the first phase, the second phase, and the third phase through the coupling relationship between the first phase, the second phase, and the third phase.

[0092] Optionally, in this embodiment, the non-volatile storage medium is configured to store program code for performing the following steps: multiple preset locations include a first preset point in an annular space of the upper-middle region of the cable terminal tail tube along the axial direction and a preset distance from the surface of the tail tube in the radial direction, a second preset point in an annular space of the upper-middle region of the cable terminal tail tube along the axial direction and a preset distance from the surface of the tail tube in the radial direction, and a third preset point in an annular space of the upper-middle region of the cable terminal tail tube along the axial direction and a preset distance from the surface of the tail tube in the radial direction.

[0093] Optionally, in this embodiment, the non-volatile storage medium is configured to store program code for performing the following steps: superimposing the initial electric field strength with the interference component attenuated by the first layer electrode through the coupling relationships between the first phase and the corresponding second layer electrode, the second phase and the corresponding second layer electrode, and the third phase and the corresponding second layer electrode, to obtain the induced voltage signal of the first phase, the induced voltage signal of the second phase, and the induced voltage signal of the third phase; amplifying and filtering the induced voltage signals of the first phase, the second phase, and the third phase respectively to obtain the modulus of the first phase. The analog voltage signals of the first phase, the second phase, and the third phase are obtained. Analog-to-digital conversion is performed on the analog voltage signals of the first phase, the second phase, and the third phase respectively to obtain digital voltage signals of the first phase, the second phase, and the third phase. Based on Fourier transform, the fundamental voltage components of the first phase, the second phase, and the third phase are extracted from the digital voltage signals of the first phase, the second phase, and the third phase respectively, and used as the voltage measurement values ​​of the first phase, the second phase, and the third phase.

[0094] Optionally, in this embodiment, the non-volatile storage medium is configured to store program code for performing the following steps: constructing an initial coupling model between the voltage measurement value and the actual voltage value based on the coupling relationship between the first phase, the second phase, and the third phase; converting the initial coupling model into an equivalent coupling model based on the symmetry relationship between multiple preset positions; decomposing the voltage measurement values ​​of the first phase, the second phase, and the third phase in the complex domain based on the equivalent coupling model to obtain a system of equations containing multiple unknowns, wherein the multiple unknowns include a first coupling coefficient, a second coupling coefficient, a third coupling coefficient, the real part of the actual voltage value of the first phase, and the imaginary part of the actual voltage value of the first phase; solving the system of equations to obtain the actual voltage phase of the first phase, the actual voltage phase of the second phase, and the actual voltage phase of the third phase, wherein the tangent of the actual voltage phase of the first phase is the ratio of the imaginary part to the real part of the actual voltage value of the first phase.

[0095] Optionally, in this embodiment, the non-volatile storage medium is configured to store program code for performing the following steps: The mathematical expression of the equivalent coupling model is as follows:

[0096] ,

[0097] in, This is the voltage measurement value for the first phase. This is the voltage measurement value for the second phase. This is the voltage measurement value for the third phase. This is the actual voltage value of the first phase. The first coupling coefficient, The second coupling coefficient, The third coupling coefficient, This is the conversion coefficient between the first phase, the second phase, and the third phase.

[0098] Optionally, in this embodiment, the non-volatile storage medium is configured to store program code for performing the following steps: using the actual voltage phase of the first phase, the actual voltage phase of the second phase, and the actual voltage phase of the third phase as reference values ​​to determine the insulation dielectric loss coefficient of the target cable.

[0099] Embodiments of the present invention also provide a computer program product, including a computer program. Optionally, in this embodiment, when the computer program is executed by a processor, it can: sense the initial electric field strength of the first phase, the initial electric field strength of the second phase, and the initial electric field strength of the third phase using multiple double-layer electric field sensors respectively set at multiple preset positions on the target cable. The double-layer electric field sensor includes a first layer electrode and a second layer electrode. The first layer electrode is grounded through a grounding wire, and the second layer electrode is used to sense the initial electric field strength. The axial height of the first layer electrode is greater than the axial height of the second layer electrode. Based on the initial electric field strength of the first phase, the initial electric field strength of the second phase, and the initial electric field strength of the third phase, the voltage measurement values ​​of the first phase, the second phase, and the third phase are determined respectively. Based on the voltage measurement values ​​of the first phase, the second phase, and the third phase, the actual voltage phase of the first phase, the actual voltage phase of the second phase, and the actual voltage phase of the third phase are determined through the coupling relationship between the first phase, the second phase, and the third phase.

[0100] The sequence numbers of the above embodiments of the present invention are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0101] In the above embodiments of the present invention, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0102] In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways. The device embodiments described above are merely illustrative; for example, the division of units can be a logical functional division, and in actual implementation, there may be other division methods. For instance, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the displayed or discussed mutual coupling, direct coupling, or communication connection may be through some interfaces; the indirect coupling or communication connection between units or modules may be electrical or other forms.

[0103] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0104] Furthermore, the functional units in the various embodiments of the present invention 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.

[0105] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a non-volatile storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, read-only memory (ROM), random access memory (RAM), portable hard drives, magnetic disks, or optical disks.

[0106] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle 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 method for detecting the phase of a three-phase voltage, characterized in that, include: Multiple double-layer electric field sensors are installed at multiple preset positions on the target cable to sense the initial electric field strength of the first phase, the initial electric field strength of the second phase, and the initial electric field strength of the third phase. The double-layer electric field sensor includes a first layer electrode and a second layer electrode. The first layer electrode is grounded through a grounding wire, and the second layer electrode is used to sense the initial electric field strength. The axial height of the first layer electrode is greater than the axial height of the second layer electrode. Based on the initial electric field strength of the first phase, the initial electric field strength of the second phase, and the initial electric field strength of the third phase, the voltage measurement values ​​of the first phase, the second phase, and the third phase are determined respectively. Based on the voltage measurements of the first phase, the second phase, and the third phase, the actual voltage phases of the first phase, the second phase, and the third phase are determined through the coupling relationship between them.

2. The method according to claim 1, characterized in that, The plurality of preset positions include a first preset point in an annular space of the upper-middle region of the first corresponding cable terminal tail pipe and a preset distance from the surface of the tail pipe in the radial direction; a second preset point in an annular space of the upper-middle region of the second corresponding cable terminal tail pipe and a preset distance from the surface of the tail pipe in the radial direction; and a third preset point in an annular space of the upper-middle region of the third corresponding cable terminal tail pipe and a preset distance from the surface of the tail pipe in the radial direction.

3. The method according to claim 1, characterized in that, The step of determining the voltage measurement values ​​of the first phase, the second phase, and the third phase based on the initial electric field strength of the first phase, the second phase, and the third phase includes: The coupling relationships between the first phase and the corresponding second layer electrode, the second phase and the corresponding second layer electrode, and the third phase and the corresponding second layer electrode are described. The initial electric field strength is superimposed with the interference component attenuated by the first layer of electrodes to obtain the induced voltage signal of the first phase, the induced voltage signal of the second phase, and the induced voltage signal of the third phase. The induced voltage signals of the first phase, the second phase, and the third phase are amplified and filtered respectively to obtain the analog voltage signals of the first phase, the second phase, and the third phase. The analog voltage signals of the first phase, the second phase, and the third phase are respectively converted from analog to digital to obtain the digital voltage signals of the first phase, the second phase, and the third phase. Based on Fourier transform, the fundamental voltage components of the first phase, the second phase, and the third phase are extracted from the digital voltage signals of the first phase, the second phase, and the third phase, respectively, and used as the voltage measurement values ​​of the first phase, the second phase, and the third phase.

4. The method according to claim 1, characterized in that, The step of determining the actual voltage phase of the first phase, the actual voltage phase of the second phase, and the actual voltage phase of the third phase based on the voltage measurements of the first phase, the second phase, and the third phase, through the coupling relationship between the first phase, the second phase, and the third phase, includes: An initial coupling model between the measured voltage value and the actual voltage value is constructed by utilizing the coupling relationship between the first phase, the second phase, and the third phase. Based on the symmetric relationship between the multiple preset positions, the initial coupling model is converted into an equivalent coupling model; Based on the equivalent coupling model, the voltage measurement values ​​of the first phase, the second phase, and the third phase are decomposed in the complex domain to obtain a system of equations containing multiple unknowns, wherein the multiple unknowns include a first coupling coefficient, a second coupling coefficient, a third coupling coefficient, the real part of the actual voltage value of the first phase, and the imaginary part of the actual voltage value of the first phase. Solving the system of equations yields the actual voltage phase of the first phase, the actual voltage phase of the second phase, and the actual voltage phase of the third phase, wherein the tangent of the actual voltage phase of the first phase is the ratio of the imaginary part to the real part of the actual voltage value of the first phase.

5. The method according to claim 4, characterized in that, The mathematical expression of the equivalent coupling model is as follows: ， in, The voltage measurement value of the first phase. This is the voltage measurement value for the second phase. The voltage measurement value of the third phase. This is the actual voltage value of the first phase. The first coupling coefficient is... The second coupling coefficient, The third coupling coefficient, The conversion coefficients between the first phase, the second phase, and the third phase are given.

6. The method according to any one of claims 1 to 5, characterized in that, Also includes: The insulation dielectric loss coefficient of the target cable is determined by using the actual voltage phase of the first phase, the actual voltage phase of the second phase, and the actual voltage phase of the third phase as reference values.

7. A three-phase voltage phase detection device, characterized in that, include: The sensing module is used to sense the initial electric field strength of the first phase, the initial electric field strength of the second phase, and the initial electric field strength of the third phase by means of multiple double-layer electric field sensors respectively set at multiple preset positions on the target cable. The double-layer electric field sensor includes a first layer electrode and a second layer electrode. The first layer electrode is grounded through a grounding wire, and the second layer electrode is used to sense the initial electric field strength. The axial height of the first layer electrode is greater than the axial height of the second layer electrode. The first determining module is used to determine the voltage measurement value of the first phase, the voltage measurement value of the second phase, and the voltage measurement value of the third phase based on the initial electric field strength of the first phase, the initial electric field strength of the second phase, and the initial electric field strength of the third phase, respectively. The second determining module is used to determine the actual voltage phase of the first phase, the actual voltage phase of the second phase, and the actual voltage phase of the third phase based on the voltage measurement values ​​of the first phase, the second phase, and the third phase, through the coupling relationship between the first phase, the second phase, and the third phase.

8. A non-volatile storage medium, characterized in that, The non-volatile storage medium includes a stored program, wherein, when the program is executed, it controls the device containing the non-volatile storage medium to perform the three-phase voltage phase detection method according to any one of claims 1 to 6.

9. A computer device, characterized in that, include: Memory and processor The memory stores computer programs; The processor is configured to execute a computer program stored in the memory, wherein when the computer program is executed, the processor performs the three-phase voltage phase detection method according to any one of claims 1 to 6.

10. A computer program product, comprising a computer program, characterized in that, When the computer program is executed by the processor, it implements the three-phase voltage phase detection method according to any one of claims 1 to 6.

Images