A method for acquiring power frequency phase reference for power distribution cables

Abstract

This invention discloses a method for acquiring power frequency phase reference data for power distribution cables, relating to the field of power distribution cable monitoring technology. The method includes: deploying fiber optic sensors on the surface of the power distribution cable and connecting them to a fiber optic demodulator; acquiring wavelength drift signals through the demodulator and transmitting them to a central control unit; using a decoupling algorithm to separate the wavelength drift signals into mechanical strain signals and temperature signals, discarding the temperature signal and retaining the mechanical strain signal; constructing a current strain model based on the physical and mechanical characteristics of the power distribution cable; inputting the mechanical strain signal into the current strain model to obtain a reconstructed current signal containing waveform and amplitude in the power distribution cable; extracting the power frequency component and power frequency phase information of the reconstructed current signal through Fourier transform, integrating it into power frequency phase data, and smoothing the power frequency phase data; summarizing the power frequency phase data from multiple fiber optic sensors to generate a phase distribution map of the cable and performing dynamic calibration.

Description

Technical Field

[0001] This invention relates to the field of power distribution cable monitoring technology, and in particular to a method for acquiring power frequency phase references for power distribution cables. Background Technology

[0002] In recent years, with the rapid development of power systems, the monitoring and fault diagnosis of distribution cables, as an important medium for power transmission, have gradually become key research directions for intelligent power system management. Traditional distribution cable monitoring methods mainly rely on electrical sensing equipment (such as current transformers and voltage transformers) to indirectly reflect the cable's operating status by measuring electrical parameters. However, these methods have shortcomings such as limited applicability, poor electromagnetic interference resistance, and insensitivity to complex operating environments, making it difficult to meet the needs of modern power distribution systems for refined monitoring and high-reliability operation. In recent years, fiber optic sensing technology has been widely used in the field of cable condition monitoring due to its high sensitivity, strong electromagnetic interference resistance, and distributed monitoring characteristics. In particular, sensing technology based on fiber Bragg gratings (FBGs) can realize real-time detection of multi-point strain and temperature on the cable surface by utilizing the high sensitivity of light wavelength to mechanical strain and temperature, providing an advanced solution for high-precision monitoring of cable operating status.

[0003] However, existing research and applications based on fiber optic sensing technology still face several technical bottlenecks. The signals acquired by fiber optic sensors typically contain coupled information of mechanical strain and temperature, lacking efficient and stable decoupling algorithms to separate related signals and eliminate temperature interference. Furthermore, existing technologies mostly focus on the "static" monitoring of cable operating conditions, lacking accurate descriptions of the "dynamic" operating conditions along the cable (such as current distribution and phase changes). In particular, the power frequency phase, as an important characteristic parameter of the power system, is closely related to cable load distribution, operating health status, and fault location, but high-precision acquisition and dynamic calibration have not yet been achieved in existing technologies. Traditional monitoring methods usually focus on the analysis of amplitude signals, ignoring phase characteristics, resulting in an incomplete description of the cable condition and failing to meet the needs of high-precision fault diagnosis and predictive maintenance. Summary of the Invention

[0004] In view of the aforementioned existing problems, the present invention is proposed.

[0005] Therefore, this invention provides a power frequency phase reference acquisition method for power distribution cables to solve the problem that the signals acquired by fiber optic sensors usually contain coupled information of mechanical strain and temperature, and there is a lack of efficient and stable decoupling algorithms to separate the relevant signals and eliminate temperature interference.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0007] In a first aspect, the present invention provides a method for acquiring a power frequency phase reference for a power distribution cable, comprising,

[0008] Fiber optic sensors are deployed on the surface of the power distribution cable and connected to a fiber optic demodulator. The fiber optic demodulator collects wavelength drift signals and transmits them to the central control unit.

[0009] A decoupling algorithm is used to separate the wavelength drift signal into a mechanical strain signal and a temperature signal, discarding the temperature signal and retaining the mechanical strain signal.

[0010] A current strain model is constructed based on the physical and mechanical properties of the power distribution cable. The mechanical strain signal is input into the current strain model to obtain the reconstructed current signal.

[0011] The power frequency component and power frequency phase information of the reconstructed current signal are extracted by Fourier transform, integrated into power frequency phase data, and then smoothed.

[0012] The power frequency phase data from multiple fiber optic sensors are aggregated to generate a phase distribution map of the cable, and dynamic calibration is performed.

[0013] As a preferred embodiment of the power frequency phase reference acquisition method for power distribution cables described in this invention, the steps of deploying fiber optic sensors on the surface of the power distribution cable and connecting them to a fiber optic demodulator, acquiring wavelength drift signals through the fiber optic demodulator, and transmitting them to the central control unit are as follows:

[0014] Fiber Bragg grating (FBG) sensors were selected as the fiber optic sensors.

[0015] An array of FBG sensors is uniformly distributed along the longitudinal direction of the power distribution cable on its surface.

[0016] Connect each FBG sensor to the multi-channel input port of the fiber optic demodulator via a fiber optic patch cord.

[0017] FBG based on spectral analysis was selected as the fiber optic demodulator, and the fiber optic demodulator was used to acquire the wavelength drift signal.

[0018] The acquired wavelength drift signal is then transmitted to the central control unit.

[0019] As a preferred embodiment of the power frequency phase reference acquisition method for power distribution cables described in this invention, the method employs a decoupling algorithm to separate the wavelength drift signal into a mechanical strain signal and a temperature signal, discarding the temperature signal and retaining the mechanical strain signal. The specific steps are as follows:

[0020] A decoupling algorithm based on a physical model separation method is used to separate the wavelength drift signal into a mechanical strain signal and a temperature signal, as expressed in the following expression:

[0021] Δλ=Δλ ε +Δλ T ;

[0022] Among them, the wavelength drift signal output by the Δλ fiber demodulator, Δλ ε Represents the mechanical strain signal, Δλ T The temperature signal ε represents the mechanical strain signal detected by the FBG sensor, and T represents the current temperature of the FBG sensor.

[0023] Based on the characteristics of fiber Bragg grating sensors, the relationship between the wavelength drift signal and the mechanical strain and temperature signals is expressed as follows:

[0024] Δλ T =k T ·T;

[0025]

[0026] Where, k T k represents the temperature sensitivity coefficient of the FBG sensor. ε This represents the strain sensitivity coefficient of the FBG sensor;

[0027] Through the formula Δλ T =k T ·T calculates the temperature signal and removes the temperature signal from Δλ;

[0028] The calculated mechanical strain signals are stored in time series format.

[0029] As a preferred embodiment of the power frequency phase reference acquisition method for power distribution cables described in this invention, the specific steps for constructing a current strain model based on the physical and mechanical characteristics of the power distribution cable are as follows:

[0030] When current flows through a power distribution cable, the surface mechanical strain signal is mainly caused by two physical and mechanical properties: electromagnetic force and thermal effect.

[0031] Based on the electromagnetic force and thermal effect caused by current flowing through the power distribution cable, a current-strain model is constructed, and the expression for the current-strain model is:

[0032]

[0033] Where I(t) represents the current signal within the distribution cable at time t. This indicates the direct relationship between transient strain caused by electromagnetic force and electric current. The cumulative and dynamic attenuation characteristics of the current-induced thermal effect are represented by ε(t), where ε(t) represents the mechanical strain signal at time t, k1 represents the electromagnetic sensitivity coefficient of the cable material, k2 represents the thermal sensitivity coefficient, and L represents the deployment length of the fiber optic sensor array. Let dt' represent the cumulative calculation from the start time t = 0 to time t, (t - t') represent the time difference from the past time point t' to time t, a represent the time decay coefficient of the thermal effect, e represent the base of the natural logarithm, and dt' represent the integral infinitesimal element.

[0034] As a preferred embodiment of the power frequency phase reference acquisition method for power distribution cables described in this invention, the specific steps for inputting the mechanical strain signal into the current strain model to obtain the reconstructed current signal are as follows:

[0035] The first term of the current strain model is input into the mechanical strain signal ε(t) at time t. The transient component of the current is obtained, and the thermal effect integral of ε(t) is calculated simultaneously. The expression for the thermal effect integral is:

[0036]

[0037] Where Δt represents the sampling time interval, n represents the number of sampling points, m represents the index variable of the time sampling point, and t m This represents the time value corresponding to the m-th time sampling point;

[0038] By superimposing the transient component and the thermal effect component using the formula of the current strain model, a reconstructed current signal I(t) containing waveform and amplitude is obtained.

[0039] As a preferred embodiment of the power frequency phase reference acquisition method for power distribution cables described in this invention, the steps of extracting the power frequency component and power frequency phase information of the reconstructed current signal through Fourier transform, integrating them into power frequency phase data, and smoothing the power frequency phase data are as follows:

[0040] Based on the reconstructed current signal I(t), a Fast Fourier Transform (FFT) is applied. With a set frequency f, the amplitude and phase of the power frequency component are extracted, expressed as follows:

[0041]

[0042] Where I(f) represents the amplitude and phase at frequency f, e ―j2πft This represents a complex exponential function, where j is the imaginary unit and π is the value of pi.

[0043] The extracted phases are smoothed using a moving average algorithm.

[0044] As a preferred embodiment of the power frequency phase reference acquisition method for power distribution cables described in this invention, the specific steps for summarizing power frequency phase data from multiple fiber optic sensors, generating a phase distribution map of the cable, and performing dynamic calibration are as follows:

[0045] Align the phase data of each sensor by time;

[0046] By summing the phase data from all sensors, a phase distribution map is generated, expressed as:

[0047] Φ(x,t)=φ i (t),x=i·d;

[0048] Where Φ(x,t) represents the phase distribution, x represents the abscissa of the sensor's spatial position along the cable length, d represents the spacing between sensors, i represents the sensor index number, and φ i (t) represents the phase value of the i-th sensor at time t.

[0049] As a preferred embodiment of the power frequency phase reference acquisition method for power distribution cables described in this invention, the dynamic calibration specifically includes the following steps:

[0050] A dynamic deviation correction model is used to eliminate phase deviation. The phase deviation expression is as follows:

[0051]

[0052] in, α represents the phase value of the i-th sensor after dynamic calibration at time t. i β represents the fixed bias correction value for the i-th sensor. i T represents the temperature drift coefficient of the i-th sensor. i (t) represents the temperature value of the i-th sensor at time t;

[0053] All calibrated phase data The dynamic phase distribution diagram of the cable is generated by integration, and the expression is:

[0054]

[0055] Where, Φ cal (x,t) represents the phase distribution after dynamic calibration;

[0056] The dynamically calibrated phase distribution Φ cal (x,t) is uploaded to the central control unit via a real-time data transmission protocol.

[0057] In a second aspect, the present invention provides a computer device, including a memory and a processor, wherein the memory stores a computer program, wherein when the computer program is executed by the processor, it implements any step of the power frequency phase reference acquisition method for power distribution cables as described in the first aspect of the present invention.

[0058] Thirdly, the present invention provides a computer-readable storage medium having a computer program stored thereon, wherein: when the computer program is executed by a processor, it implements any step of the power frequency phase reference acquisition method for power distribution cables as described in the first aspect of the present invention.

[0059] The beneficial effects of this invention are as follows: By deploying fiber Bragg grating (FBG) sensors on the surface of power distribution cables and combining them with fiber optic demodulators, this invention achieves high-sensitivity, electromagnetic interference-resistant wavelength drift signal acquisition. A decoupling algorithm separates the signal into mechanical strain and temperature signals, eliminating temperature interference and significantly improving signal accuracy. A current strain model is constructed to convert the mechanical strain signal into a current signal containing waveform and amplitude, considering both the instantaneous effect of electromagnetic force and the dynamic characteristics of thermal effects, making the model closer to the actual operating environment. Fast Fourier Transform (FFT) is used to effectively extract the power frequency component and phase information of the current signal, and smoothing processing eliminates noise interference, ensuring the stability and continuity of phase data. Finally, by summarizing multi-point sensor data to generate a dynamic phase distribution map and combining it with a dynamic calibration model to eliminate the influence of deviation and drift, high-precision monitoring of the cable's power frequency phase is achieved. Overall, this invention solves the problems of low power frequency phase acquisition accuracy, poor anti-interference capability, and insufficient dynamic calibration in existing technologies, providing important technical support for cable operation status monitoring, fault location, and intelligent power systems. Attached Figure Description

[0060] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0061] Figure 1 This is a flowchart of the power frequency phase reference acquisition method for power distribution cables in Example 1.

[0062] Figure 2 This is a schematic diagram of the two-dimensional phase distribution map in Example 1. Detailed Implementation

[0063] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0064] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0065] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0066] Example 1, referring to Figure 1 and Figure 2 This is the first embodiment of the present invention, which provides a method for acquiring the power frequency phase reference of a power distribution cable, including the following steps:

[0067] S1. Install fiber optic sensors on the surface of the power distribution cable and connect them to the fiber optic demodulator. Collect wavelength drift signals through the fiber optic demodulator and transmit them to the central control unit.

[0068] The reasons for choosing fiber Bragg grating (FBG) sensors as fiber optic sensors are as follows: FBG sensors can accurately sense minute mechanical strain and temperature changes with a resolution down to the picometer level, making them suitable for capturing strain on cable surfaces; FBG sensors operate based on optical principles and are unaffected by strong electromagnetic fields around cables, unlike traditional current sensors; and multiple FBG sensors can be deployed on a single optical fiber using wavelength division multiplexing (WDM) technology, enabling multi-point monitoring.

[0069] On the surface of the power distribution cable, an array of FBG sensors is evenly distributed along the longitudinal direction of the cable. The spacing of the array can be selected according to the cable length and monitoring accuracy requirements. Epoxy resin is used to firmly attach the FBG sensors to the surface of the cable outer sheath to ensure that the fiber optic sensors are in close contact with the cable surface so that the strain signal can be accurately transmitted to the sensors. A protective layer (such as polytetrafluoroethylene tubing or heat shrink tubing) is covered on the outside of the sensors to prevent mechanical damage and environmental corrosion.

[0070] Connect each FBG sensor to the multi-channel input port of the fiber optic demodulator via fiber optic patch cords to ensure signal integrity and low-loss transmission. Low-loss single-mode fiber optic patch cords should be used, and appropriate protection should be provided at the connection points (such as using fiber optic connector protective sleeves).

[0071] Fiber optic gamut generators (FBGs) based on spectral analysis were selected as the fiber optic demodulator. A communication protocol (such as Ethernet or fiber optic communication) was configured between the fiber optic demodulator and the central control unit to ensure real-time transmission of high-frequency sampling data. The fiber optic demodulator was then used to acquire wavelength-shifted signals.

[0072] The acquired wavelength drift signal is then transmitted to the central control unit;

[0073] During the deployment and connection of fiber optic sensors, the anti-interference capabilities and distributed monitoring capabilities of fiber Bragg gratings (FBGs) were combined, and the deployment spacing (every 2 meters) and fixing method (epoxy resin bonding + protective layer covering) were specified, which improved the practicality of the solution.

[0074] In the processing of wavelength drift signals, a temperature compensation formula was constructed. By correcting wavelength drift signals using real-time temperature data, mechanical strain signals can be accurately separated.

[0075] The data transmission process adopts high-speed Ethernet or fiber optic communication to ensure the real-time performance and integrity of multi-point sensor data.

[0076] The invention features strong coherence between its various steps: the extraction of wavelength drift signals provides the foundation for subsequent strain signal calculations, while the extraction of strain signals directly serves the reconstruction of current signals in the next step.

[0077] S2. A decoupling algorithm is used to separate the wavelength drift signal into a mechanical strain signal and a temperature signal, discarding the temperature signal and retaining the mechanical strain signal.

[0078] A decoupling algorithm based on a physical model separation method is used to separate the wavelength drift signal into a mechanical strain signal and a temperature signal. The wavelength drift signal expression is as follows:

[0079] Δλ=Δλ ε +Δλ T ;

[0080] Among them, the wavelength drift signal output by the Δλ fiber demodulator, Δλ ε This represents the mechanical strain signal, specifically the wavelength shift signal caused by mechanical strain, Δλ. T The temperature signal represents the wavelength shift signal caused by changes in ambient temperature; ε represents the mechanical strain signal detected by the FBG sensor; and T represents the current temperature of the FBG sensor.

[0081] The core innovation of this step lies in using a physical model separation method to decompose the wavelength drift signal Δλ into mechanical strain and temperature signals. This separation method directly utilizes the dual sensitivity of the FBG sensor to mechanical strain and temperature, and accurately describes the superposition relationship between the two through the wavelength drift signal expression.

[0082] Based on the characteristics of fiber Bragg grating sensors, the relationship between the wavelength drift signal and the mechanical strain and temperature signals is expressed as follows:

[0083] ΔλT =k T ·T;

[0084]

[0085] Where, k T k represents the temperature sensitivity coefficient of the FBG sensor. ε This represents the strain sensitivity coefficient of the FBG sensor;

[0086] Through the formula Δλ T =k T The temperature signal is calculated using T and then removed from Δλ to ensure the accuracy of the mechanical strain signal.

[0087] After removing the temperature signal, the remaining wavelength shift Δλ―k T There is a linear relationship between T and the mechanical strain signal ε, with the proportionality coefficient being the strain sensitivity coefficient. The strain signal k is ultimately calculated using the formula described above. ε ;

[0088] To address the problem of mechanical strain signal distortion caused by temperature interference in existing technologies, this invention introduces a temperature sensitivity coefficient and real-time temperature parameters, utilizing the formula Δλ T =k T ·T performs quantitative estimation and rejection of temperature signals by removing Δλ T This effectively eliminates the interference of temperature changes on the signal, ensures the accuracy of mechanical strain signals, and solves the problem of signal measurement errors caused by changes in ambient temperature in traditional technologies.

[0089] The calculated mechanical strain signals are stored in time series format.

[0090] S3. Construct a current strain model based on the physical and mechanical characteristics of the power distribution cable, input the mechanical strain signal into the current strain model, and obtain the reconstructed current signal.

[0091] When current flows through a power distribution cable, the surface mechanical strain signal is mainly caused by two physical and mechanical properties: electromagnetic force and thermal effect.

[0092] Electromagnetic force: The magnetic field generated by the electric current creates an electromagnetic force, which causes changes in strain on the cable surface;

[0093] Thermal effect: The Joule heat generated by the current raises the cable temperature, causing thermal expansion and resulting in surface strain changes;

[0094] Based on the electromagnetic force and thermal effect caused by current flowing through the power distribution cable, a current-strain model is constructed, and the expression for the current-strain model is:

[0095]

[0096] Where I(t) represents the current signal within the distribution cable at time t. This indicates the direct relationship between transient strain caused by electromagnetic force and electric current. The cumulative and dynamic attenuation characteristics of the current-induced thermal effect are represented by ε(t), where ε(t) represents the mechanical strain signal at time t, k1 represents the electromagnetic sensitivity coefficient of the cable material, k2 represents the thermal sensitivity coefficient, and L represents the deployment length of the fiber optic sensor array. dt' represents the cumulative calculation from the start time t = 0 to time t, (t - t') represents the time difference from the past time point t' to time t, a represents the time decay coefficient of the thermal effect, e represents the base of the natural logarithm, and dt' represents the integral infinitesimal element.

[0097] Compared to the traditional simple linear model, the formula takes into account the dynamic characteristics of thermal effects (through an exponential decay function), making the model more consistent with the actual cable operating environment.

[0098] By describing the different effects of electromagnetic force and thermal effect in separate terms, the formula has higher physical explanatory power and application accuracy, and is suitable for current signal reconstruction under complex loads.

[0099] The first term of the current strain model is input into the mechanical strain signal ε(t) at time t. The transient component of the current is obtained, and the thermal effect integral of ε(t) is calculated simultaneously. The expression for the thermal effect integral is:

[0100]

[0101] Where Δt represents the sampling time interval, n represents the number of sampling points, m represents the index variable of the time sampling point, and t m This represents the time value corresponding to the m-th time sampling point;

[0102] By superimposing the transient component and the thermal effect component using the formula of the current strain model, a reconstructed current signal I(t) containing waveform and amplitude is obtained.

[0103] S4. Extract the power frequency component and power frequency phase information of the reconstructed current signal through Fourier transform, integrate them into power frequency phase data, and smooth the power frequency phase data.

[0104] Based on the reconstructed current signal I(t), a Fast Fourier Transform (FFT) is applied, with the frequency f set to 50Hz, to extract the amplitude and phase of the power frequency component. The expression is as follows:

[0105]

[0106] Where I(f) represents the amplitude and phase at frequency f, e―j2πft This represents a complex exponential function, where j is the imaginary unit and π is the value of pi.

[0107] The extracted phase is smoothed using a moving average algorithm to eliminate noise and transient interference. The expression is as follows:

[0108]

[0109] Where, φ smooth (t) represents the power frequency phase signal after smoothing by moving average at time t, N represents the size of the sliding window, and δ represents the index variable within the sliding window.

[0110] S5. Summarize the power frequency phase data of multiple fiber optic sensors, generate the phase distribution map of the cable, and perform dynamic calibration.

[0111] The fiber Bragg grating (FBG) sensors, which are longitudinally arranged on the surface of each power distribution cable, collect mechanical strain signals through the fiber Bragg grating (FBG) sensor array. The input current strain model is used to calculate the reconstructed current signal I(t), as well as the phase data of the power frequency component extracted by fast Fourier transform (FFT).

[0112] The phase data of each sensor are aligned by time to ensure that the sampling time of all sensors is consistent. This is achieved through the time synchronization mechanism (GPS time synchronization) of the central control unit.

[0113] The phase data from all sensors are aggregated to generate a phase distribution map, which is represented by a two-dimensional function, expressed as:

[0114] Φ(x,t)=φ i (t),x=i·d;

[0115] Where Φ(x,t) represents the phase distribution, x represents the abscissa of the sensor's spatial position along the cable length, d represents the spacing between sensors, i represents the sensor index number, and φ i (t) represents the phase value of the i-th sensor at time t;

[0116] This step involves summarizing the phase data from multiple fiber optic sensors deployed on the cable surface to generate a complete cable phase distribution map. In existing technologies, multi-point monitoring systems typically only provide data from scattered monitoring points, making it difficult to form an overall spatial distribution map. This invention addresses this by using the formula Φ(x,t)=φ i (t),x=i·d, with the spatial position x of the sensor as the abscissa, a two-dimensional function form of phase distribution is constructed, so that the power frequency phase state along the cable can be presented intuitively;

[0117] It should be noted that integrating the originally discrete sensor data into a continuous spatial distribution facilitates a global analysis of the overall operating status of the cable. This method can quickly identify whether there are abnormal areas (such as fault points or overload hotspots) along the length of the cable.

[0118] Due to the influence of ambient temperature and material properties, the initial phase values ​​of each sensor may deviate, and phase drift may occur due to aging or external disturbances during long-term operation. Therefore, dynamic calibration is required to ensure the accuracy of the phase reference.

[0119] A dynamic deviation correction model is used to eliminate phase deviation. The phase deviation expression is as follows:

[0120]

[0121] in, α represents the phase value of the i-th sensor after dynamic calibration at time t. i β represents the fixed bias correction value for the i-th sensor. i T represents the temperature drift coefficient of the i-th sensor. i (t) represents the temperature value of the i-th sensor at time t;

[0122] The calibration process is as follows:

[0123] Perform initial calibration on each sensor and measure the fixed deviation correction value α. i and temperature drift coefficient β i ;

[0124] Real-time acquisition of temperature data T from sensors i (t);

[0125] Calculate the calibrated phase data according to the phase deviation formula.

[0126] All calibrated phase data The dynamic phase distribution diagram of the cable is generated by integration, and the expression is:

[0127]

[0128] Where, Φ cal (x,t) represents the phase distribution after dynamic calibration, which can accurately reflect the power frequency phase state of the cable along its length.

[0129] The dynamically calibrated phase distribution Φ cal (x,t) is uploaded to the central control unit via a real-time data transmission protocol (such as a high-speed Ethernet protocol);

[0130] The central control unit visualizes the phase distribution map and compares it with historical phase benchmarks to identify abnormal phase areas, thus assisting in fault location and diagnosis.

[0131] This invention solves the problems of data dispersion, time inconsistency, and long-term drift in multi-point monitoring systems by summarizing the phase data of fiber optic sensors and generating a dynamically calibrated phase distribution map. The time synchronization mechanism in the key steps ensures the consistency of the data, and the dynamic deviation correction model effectively improves the accuracy of the phase data. The final generated dynamic phase distribution map has high precision and real-time performance, and can be used for cable operation status monitoring and fault diagnosis, which has important technical value and application prospects.

[0132] This embodiment also provides a computer device applicable to the power frequency phase reference acquisition method for power distribution cables, including: a memory and a processor; the memory is used to store computer-executable instructions, and the processor is used to execute the computer-executable instructions to implement the power frequency phase reference acquisition method for power distribution cables as proposed in the above embodiment.

[0133] The computer device can be a terminal, comprising a processor, memory, communication interface, display screen, and input devices connected via a system bus. The processor provides computing and control capabilities. The memory includes non-volatile storage media and internal memory. The non-volatile storage media stores the operating system and computer programs. The internal memory provides an environment for the operation of the operating system and computer programs stored in the non-volatile storage media. The communication interface is used for wired or wireless communication with external terminals; wireless communication can be achieved through Wi-Fi, carrier networks, NFC (Near Field Communication), or other technologies. The display screen can be an LCD screen or an e-ink screen. The input devices can be a touch layer covering the display screen, buttons, a trackball, or a touchpad on the computer device's casing, or an external keyboard, touchpad, or mouse.

[0134] This embodiment also provides a storage medium storing a computer program. When executed by a processor, the program implements the power frequency phase reference acquisition method for power distribution cables as proposed in the above embodiments. The storage medium can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as Static Random Access Memory (SRAM), Electrically Erasable Programmable Read-Only Memory (EEPROM), Erasable Programmable Read Only Memory (EPROM), Programmable Red-Only Memory (PROM), Read-Only Memory (ROM), magnetic storage, flash memory, magnetic disk, or optical disk.

[0135] In summary, this invention achieves high-sensitivity, electromagnetic interference-resistant wavelength drift signal acquisition by deploying fiber Bragg grating (FBG) sensors on the surface of power distribution cables and combining them with fiber optic demodulators. A decoupling algorithm separates the signal into mechanical strain and temperature signals, eliminating temperature interference and significantly improving signal accuracy. A current strain model is constructed to convert the mechanical strain signal into a current signal containing waveform and amplitude, considering both the instantaneous effect of electromagnetic force and the dynamic characteristics of thermal effects, making the model more closely resemble the actual operating environment. Fast Fourier Transform (FFT) is used to effectively extract the power frequency component and phase information of the current signal, and smoothing processes eliminate noise interference, ensuring the stability and continuity of phase data. Finally, a dynamic phase distribution map is generated by summarizing multi-point sensor data, and a dynamic calibration model is used to eliminate the influence of deviation and drift, achieving high-precision monitoring of the cable's power frequency phase. Overall, this invention solves the problems of low power frequency phase acquisition accuracy, poor anti-interference capability, and insufficient dynamic calibration in existing technologies, providing important technical support for cable operation status monitoring, fault location, and intelligent power systems.

[0136] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. 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 be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for acquiring power frequency phase reference of a power distribution cable, characterized in that: include: Fiber optic sensors are deployed on the surface of the power distribution cable and connected to a fiber optic demodulator. The fiber optic demodulator collects wavelength drift signals and transmits them to the central control unit. A decoupling algorithm is used to separate the wavelength drift signal into a mechanical strain signal and a temperature signal, discarding the temperature signal and retaining the mechanical strain signal. A current strain model is constructed based on the physical and mechanical properties of the power distribution cable. The mechanical strain signal is input into the current strain model to obtain the reconstructed current signal. Based on the electromagnetic force and thermal effect caused by current flowing through the power distribution cable, a current-strain model is constructed, and the expression for the current-strain model is: Where I(t) represents the current signal within the distribution cable at time t. This indicates the direct relationship between transient strain caused by electromagnetic force and electric current. The cumulative and dynamic attenuation characteristics of the current-induced thermal effect are represented by ε(t), where ε(t) represents the mechanical strain signal at time t, k1 represents the electromagnetic sensitivity coefficient of the cable material, k2 represents the thermal sensitivity coefficient, and L represents the deployment length of the fiber optic sensor array. dt′ represents the cumulative calculation from the start time t=0 to time t, (tt′) represents the time difference from the past time point t′ to time t, a represents the time decay coefficient of the thermal effect, e represents the base of the natural logarithm, and dt′ represents the integral infinitesimal element. The first term of the current strain model is input into the mechanical strain signal ε(t) at time t. The transient component of the current is obtained, and the thermal effect integral of ε(t) is calculated simultaneously. The expression for the thermal effect integral is: Where Δt represents the sampling time interval, n represents the number of sampling points, m represents the index variable of the time sampling point, and t m This represents the time value corresponding to the m-th time sampling point; By superimposing the transient component and the thermal effect component using the formula current strain model expression, the reconstructed current signal I(t) containing waveform and amplitude is obtained; The power frequency component and power frequency phase information of the reconstructed current signal are extracted by Fourier transform, integrated into power frequency phase data, and then smoothed. The power frequency phase data from multiple fiber optic sensors are aggregated to generate a phase distribution map of the cable, and dynamic calibration is performed. Align the phase data of each sensor by time; By summing the phase data from all sensors, a phase distribution map is generated, expressed as: Φ(x,t)=φ i (t),x=i·d; Where Φ(x, t) is the phase distribution, x represents the abscissa of the sensor's spatial position along the cable length, d represents the spacing between sensors, i represents the sensor index number, and φ i (t) represents the phase value of the i-th sensor at time t; A dynamic deviation correction model is used to eliminate phase deviation. The phase deviation expression is as follows: f i，cal (t)=φ i (t)-a i -b i ·T i (t); Where, φ i，cal (t) represents the phase value of the i-th sensor after dynamic calibration at time t, α i β represents the fixed bias correction value for the i-th sensor. i T represents the temperature drift coefficient of the i-th sensor. i (t) represents the temperature value of the i-th sensor at time t; All calibrated phase data φ i，cal (t) Integration generates a dynamic phase distribution diagram of the cable, expressed as: Φ cal (x,t)=φ i，cal (t),x=i·d; Where, Φ cal (x, t) represents the phase distribution after dynamic calibration; The dynamically calibrated phase distribution Φ cal (x, t) is uploaded to the central control unit via a real-time data transmission protocol.

2. The power frequency phase reference acquisition method for power distribution cables as described in claim 1, characterized in that: The steps for deploying fiber optic sensors on the surface of the power distribution cable and connecting them to a fiber optic demodulator, acquiring wavelength drift signals through the demodulator, and transmitting them to the central control unit are as follows: Fiber Bragg grating (FBG) sensors were selected as the fiber optic sensors. An array of FBG sensors is uniformly distributed along the longitudinal direction of the power distribution cable on its surface. Connect each FBG sensor to the multi-channel input port of the fiber optic demodulator via a fiber optic patch cord. FBG based on spectral analysis was selected as the fiber optic demodulator, and the fiber optic demodulator was used to acquire wavelength drift signals. The acquired wavelength drift signal is then transmitted to the central control unit.

3. The power frequency phase reference acquisition method for power distribution cables as described in claim 2, characterized in that: The decoupling algorithm is used to separate the wavelength drift signal into a mechanical strain signal and a temperature signal, discarding the temperature signal and retaining the mechanical strain signal. The specific steps are as follows: A decoupling algorithm based on a physical model separation method is used to separate the wavelength drift signal into a mechanical strain signal and a temperature signal, as expressed in the following expression: Dl=Dl ε +Dl T ; Among them, the wavelength drift signal output by the Δλ fiber demodulator, Δλ ε Represents the mechanical strain signal, Δλ T ε represents the temperature signal, ε represents the mechanical strain signal detected by the FBG sensor, and T represents the current temperature of the FBG sensor. Based on the characteristics of fiber Bragg grating sensors, the relationship between the wavelength drift signal and the mechanical strain and temperature signals is expressed as follows: Dl T =k T ·T; Where, k T k represents the temperature sensitivity coefficient of the FBG sensor. ε This represents the strain sensitivity coefficient of the FBG sensor; Through the formula Δλ T =k T ·T calculates the temperature signal and removes the temperature signal from Δλ; The calculated mechanical strain signals are stored in time series format.

4. The power frequency phase reference acquisition method for power distribution cables as described in claim 3, characterized in that: The steps for extracting the power frequency component and power frequency phase information of the reconstructed current signal through Fourier transform, integrating them into power frequency phase data, and smoothing the power frequency phase data are as follows: Based on the reconstructed current signal I(t), a Fast Fourier Transform (FFT) is applied. With a set frequency f, the amplitude and phase of the power frequency component are extracted, expressed as follows: Where I(f) represents the amplitude and phase at frequency f, e -j2πft This represents a complex exponential function, where j is the imaginary unit and π is the value of pi. The extracted phases are smoothed using a moving average algorithm.

5. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that: When the processor executes the computer program, it implements the steps of the power frequency phase reference acquisition method for power distribution cables according to any one of claims 1 to 4.

6. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by the processor, it implements the steps of the power frequency phase reference acquisition method for power distribution cables according to any one of claims 1 to 4.

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