A power distribution optical fiber-based differential protection method, device, equipment and medium

Abstract

The application discloses a kind of based on distribution optical fiber differential protection method, device, equipment and medium, especially related to differential protection technical field, the method includes: obtaining the first current data, second current data and physical state parameter of target distribution optical fiber;According to the first current data, second current data and physical state parameter, determine the state type where target distribution optical fiber is located;Wherein, the state type includes physical fault state and communication link abnormal state;When determining that the target distribution optical fiber is in physical fault state or communication link abnormal state, according to the state type, corresponding differential protection control instruction is generated;The differential protection control instruction includes open trip instruction or lockout trip instruction.The application can solve the problem that existing differential protection technology is prone to error trip action due to the difficulty in distinguishing physical fault and communication link abnormality at the level of differential current.

Description

Technical Field

[0001] This invention relates to the field of differential protection technology, and in particular to a differential protection method, device, equipment and medium based on power distribution optical fiber. Background Technology

[0002] With the high penetration rate of distributed photovoltaic, energy storage, and other new energy sources into the distribution network, the diversification of power sources in the distribution network has led to more complex short-circuit current distribution paths and bidirectional power flow has become the norm. Traditional three-stage current protection based on single-end electrical quantities can no longer guarantee selectivity and sensitivity. Differential protection identifies faults by comparing the current at two or more ends of the line. It is unaffected by changes in system operating mode and can act quickly during faults within the zone and remain reliably inactive during faults outside the zone. It has become a key means to ensure power supply reliability in distribution networks with high penetration of new energy sources. Distribution optical fiber (such as OPGW and ADSS optical cables) has become the mainstream communication carrier for distribution network differential protection due to its advantages such as high bandwidth, strong resistance to electromagnetic interference, and low transmission delay.

[0003] Currently, differential protection schemes based on power distribution fiber optic cables are typically implemented as follows: protection terminals are deployed at both ends of the line. Each terminal collects its own current data and transmits it to the other end via a fiber optic channel, while simultaneously receiving current data from the other end. The differential current value is calculated based on the current values ​​at both ends. When the differential current value exceeds a preset threshold, it is determined to be a fault within the zone, and a trip command is issued. However, the current measurement data of the differential protection shares the same physical medium (fiber optic cable) with the communication link. When the fiber optic communication link experiences anomalies such as bit errors, latency jitter, or data packet loss, the communication anomaly manifests at the differential current level as an excessive differential current value after comparing the current data at both ends, just like a real physical fault. Existing protection schemes heavily rely on the differential current value as a criterion, making it impossible to distinguish whether the excessive value originates from a real physical fault in the line or from current data distortion caused by communication link anomalies. This will lead to the protection device easily tripping falsely when the communication link is abnormal, causing unnecessary power outages and seriously affecting the power supply reliability of the distribution network. Summary of the Invention

[0004] This invention provides a differential protection method, device, equipment, and medium based on power distribution optical fiber, which can solve the problem that existing differential protection technologies are prone to erroneous tripping due to the difficulty in distinguishing between physical faults and communication link abnormalities at the differential current level.

[0005] In a first aspect, embodiments of the present invention provide a differential protection method based on power distribution optical fiber, comprising: The method involves acquiring first current data, second current data, and physical state parameters of the target power distribution fiber; wherein the first current data and second current data are obtained by modulating the terminals at different locations of the target power distribution fiber; the physical state parameters are obtained by solving the reverse Rayleigh scattering signal on the target power distribution fiber; and the physical state parameters include several state data items. Based on the first current data, the second current data, and the physical state parameters, the state type of the target power distribution fiber is determined; wherein, the state type includes physical fault state and communication link abnormal state; When it is determined that the target power distribution fiber is in a physical fault state or a communication link abnormal state, a corresponding control command is generated according to the state type, and the control command is sent to the execution end to control the execution end to perform the corresponding differential protection action; wherein, the control command includes an open trip command or a blocked trip command.

[0006] This invention provides basic data for differential current calculation by acquiring first and second current data, and obtains physical state parameters through reverse Rayleigh scattering signals. These physical state parameters originate from Rayleigh scattering of the optical fiber itself and are a direct mapping of the physical world (temperature, stress, vibration), unaffected by communication link anomalies such as communication errors and delay jitter. This provides independent verification evidence for distinguishing between true and false differential current exceedances. By fusing electrical evidence (current data) and physical evidence (physical state parameters) for cross-validation, the output results are differentiated into two different states at the criterion level. Based on the state type, corresponding trip commands are generated, thereby reducing the error rate of tripping actions during differential protection.

[0007] Compared with existing technologies, this invention constructs a complete framework for parallel acquisition of dual-dimensional data, fusion determination of state types, and differentiated output of control commands. At the criterion level, it distinguishes the output results into two distinct states: physical faults and communication link anomalies. This framework directly breaks the unidirectional logic of tripping upon exceeding limits in traditional solutions, enabling the system to differentiate between genuine physical faults and false exceedances in the information world, thereby executing the corresponding correct tripping operation. This solves the problem that existing differential protection technologies are prone to erroneous tripping actions due to the difficulty in distinguishing between physical faults and communication link anomalies at the differential current level, significantly improving the power supply reliability of the distribution network.

[0008] In some preferred embodiments of the first aspect, the state type of the target power distribution fiber is determined based on the first current data, the second current data, and physical state parameters, including: Calculate the differential current value based on the first current data and the second current data; When the differential current value is greater than the preset differential current threshold and at least one of the physical state parameters is greater than the corresponding abnormal state threshold, the target power distribution fiber is determined to be in a physical fault state. When the differential current value is greater than the preset differential current threshold and none of the status data in the physical state parameters are greater than the corresponding abnormal state threshold, the target power distribution optical fiber is determined to be in an abnormal communication link state.

[0009] This invention determines a physical fault when the differential current exceeds the limit and there are also anomalies in the physical state parameters; conversely, it determines a communication link anomaly when the differential current exceeds the limit but all physical state parameters are normal. The underlying logic of this pair of rules lies in the fact that physical state parameters originate from Rayleigh scattering in optical fibers and are a direct mapping of the physical world, completely independent of the quality status of the communication link. Therefore, when current data indicates a fault while the physical world indicates everything is normal, two independent pieces of evidence conflict. This invention, however, adopts physical evidence to further determine whether the current exceedance is due to a communication link anomaly. This determination rule directly solves the core deficiency of traditional solutions in being unable to distinguish between true and false current exceedances.

[0010] In some preferred embodiments of the first aspect, a corresponding control command is generated based on the state type, including: When it is determined that the target power distribution fiber is in a physical fault state, an open trip command is generated; When it is determined that the target power distribution fiber is in an abnormal communication link state, a blocking trip command and a communication parameter optimization command are generated.

[0011] This invention generates the correct tripping command based on two state determination results. In the case of a physical fault, the tripping is initiated to isolate the actual fault; in the case of a communication anomaly, the tripping is blocked to prevent false tripping, and a communication parameter optimization command is added. This ensures that the actual fault is quickly isolated to protect the power grid, while simultaneously shielding false exceedances caused by communication interference to prevent unwarranted power outages. Furthermore, the introduction of the communication parameter optimization command means that the system actively intervenes in the communication link while blocking, suppressing anomalies at the source, rather than passively repeating blocking.

[0012] In some preferred embodiments of the first aspect, the acquisition of the physical state parameters specifically includes: The reverse Rayleigh scattering signal generated in the target power distribution fiber is received; wherein the reverse Rayleigh scattering signal is generated by sending a probe light signal to the target power distribution fiber. The physical state parameters are obtained by performing time-domain and frequency-domain analysis on the reverse Rayleigh scattering signal.

[0013] This invention utilizes the inherent sensitivity of optical fibers to temperature, stress, and vibration, eliminating the need for any additional independent sensors. This ensures that the acquisition of physical evidence and the transmission of current data are fully reusable at the hardware level, thereby transforming the information dimension from single-dimensional to two-dimensional without increasing costs.

[0014] In some preferred embodiments of the first aspect, the physical state parameters include line temperature distribution, line vibration parameters, and line stress parameters; Specifically, the physical state parameters are obtained by performing time-domain and frequency-domain analysis on the reverse Rayleigh scattering signal, including: By performing time-domain analysis on the reverse Rayleigh scattering signal, the signal intensity change and time delay fluctuation were obtained; The line temperature distribution is calculated based on the signal strength change. Based on the time delay fluctuation, combined with OTDR positioning, the line vibration parameters are calculated; wherein, the line vibration parameters include the line vibration location and the line vibration intensity. By performing frequency domain analysis on the reverse Rayleigh scattering signal, the phase fluctuation is obtained, and the line stress parameters are calculated based on the phase fluctuation.

[0015] In this embodiment of the invention, temperature corresponds to environmental or equipment anomalies, vibration corresponds to tree obstructions or external damage, and stress corresponds to icing or tower settlement. These three physical quantities cover the most common causes of anomalies in distribution network lines, ensuring sufficient coverage of physical evidence. More importantly, each of the three physical quantities corresponds to three different signal characteristics: intensity, time delay, and phase. This defines a complete profile of the physical evidence, thereby ensuring the accuracy of subsequent anomaly determination.

[0016] In some preferred embodiments of the first aspect, the generation of the communication optimization instructions includes: Based on the physical state parameters and the preset adjustment threshold, a parameter adjustment instruction for the communication signal is generated; wherein, the parameter adjustment instruction includes at least one of the following: modulation order adjustment instruction or transmit power adjustment instruction.

[0017] In this embodiment of the invention, modulation order adjustment is used to address the decrease in signal-to-noise ratio caused by high temperature, thereby improving anti-interference capability by reducing the order; transmit power adjustment is used to address the increased fiber loss caused by low temperature or vibration, thereby compensating for attenuation by increasing power. As a result, after an anomaly in the communication link is identified, the system does not passively wait for the next interference to occur, but actively adjusts the communication parameters to a state more suitable for the current operating conditions based on the environmental information perceived from the physical world, thereby reducing the probability of the same interference recurring. This achieves a closed loop from perception and identification to self-healing, transforming the avoidance of a one-time false trip into a systemic improvement in anti-interference capability.

[0018] Among the preferred options in the first aspect are: The system continuously receives the physical state parameters of the target power distribution fiber and determines whether each state data in the physical state parameters has been restored to the corresponding preset normal state range. When it is determined that all the state data have been restored to the corresponding preset normal state range, a reset command is generated and sent to the execution terminal.

[0019] This invention continuously monitors physical state parameters. When all state data returns to the normal range, it automatically generates a reset command and sends it to the execution end. Thus, after a physical fault is isolated (e.g., after workers clear tree obstructions), the system senses the anomaly has been eliminated through the recovery of physical state parameters and autonomously restores to its default operating state without manual intervention. The system can also autonomously reset after communication interference is suppressed. This transforms the entire technical solution from a single protective action into a complete closed-loop system encompassing sensing, judgment, handling, recovery, and re-sensing, significantly reducing the operational burden.

[0020] Secondly, embodiments of the present invention provide a differential protection device based on power distribution optical fiber, including a data acquisition module, a state type determination module, and a differential protection control module, wherein... The data acquisition module acquires first current data, second current data, and physical state parameters of the target power distribution fiber; wherein, the first current data and second current data are obtained by modulating the terminals at different locations of the target power distribution fiber; the physical state parameters are obtained by solving the reverse Rayleigh scattering signal on the target power distribution fiber; the physical state parameters include several state data items. The state type determination module is used to determine the state type of the target power distribution optical fiber based on the first current data, the second current data, and the physical state parameters; wherein, the state type includes physical fault state and communication link abnormal state; The differential protection control module is used to generate a corresponding control command according to the state type when it is determined that the target power distribution fiber is in a physical fault state or a communication link abnormal state, and send the control command to the execution end to control the execution end to perform the corresponding differential protection action; wherein, the control command includes an open trip command or a blocked trip command.

[0021] This invention employs a data acquisition module to obtain first and second current data, providing fundamental data for differential current calculation. Physical state parameters are then obtained through reverse Rayleigh scattering signals. These physical state parameters originate from Rayleigh scattering within the optical fiber itself, representing a direct mapping of the physical world (temperature, stress, vibration), and are unaffected by communication link anomalies such as communication errors and latency jitter. This provides independent verification evidence for distinguishing between true and false differential current exceedances. A state type determination module integrates electrical evidence (current data) and physical evidence (physical state parameters) for cross-validation, thereby differentiating the output results into two distinct states at the criterion level. Finally, a differential protection control module generates corresponding trip commands based on the state type, reducing the error rate of tripping actions during differential protection.

[0022] Thirdly, embodiments of the present invention provide a terminal device, including: a processor, a memory, a communication interface, and a communication bus, wherein the processor, the memory, and the communication interface communicate with each other through the communication bus; The memory is used to store at least one executable instruction that causes the processor to perform the operation of the differential protection method based on power distribution fiber as described in any of the above.

[0023] Fourthly, embodiments of the present invention provide a computer-readable storage medium, the computer-readable storage medium including a stored computer program, wherein, when the computer program is executed, it controls the device or apparatus where the computer-readable storage medium is located to perform the differential protection method based on power distribution optical fiber as described in any of the above.

[0024] The above description is merely an overview of the technical solutions of the embodiments of the present invention. In order to better understand the technical means of the embodiments of the present invention and to implement them in accordance with the contents of the specification, and to make the above and other objects, features and advantages of the embodiments of the present invention more apparent and understandable, specific embodiments of the present invention are described below. Attached Figure Description

[0025] Figure 1 A schematic diagram of a differential protection method based on power distribution optical fiber provided in an embodiment of the present invention; Figure 2 A differential protection system architecture diagram based on power distribution optical fiber is provided for an embodiment of the present invention; Figure 3 This is an example of a light-sensing fusion frame structure diagram from an embodiment of the present invention; Figure 4 A flowchart illustrating the calculation of a reverse Rayleigh scattering signal, as exemplified by an embodiment of the present invention; Figure 5A schematic diagram of the differential protection process based on power distribution optical fiber provided in an embodiment of the present invention; Figure 6 This is a structural diagram of a differential protection device based on power distribution optical fiber, provided for an embodiment of the present invention. Detailed Implementation

[0026] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. 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 are within the scope of protection of the present invention.

[0027] Example 1: like Figure 1 As shown, an embodiment of the present invention provides a differential protection method based on power distribution optical fiber, comprising: S101, acquire the first current data, the second current data, and the physical state parameters of the target power distribution fiber; wherein, the first current data and the second current data are obtained by modulating the terminals at different locations of the target power distribution fiber; the physical state parameters are obtained by solving the reverse Rayleigh scattering signal on the target power distribution fiber; the physical state parameters include several state data items. Preferably, the differential protection method of the present invention can be adopted as follows: Figure 2 The system architecture shown is implemented. Figure 2 The demonstration showcased the interconnectivity between four core components: the Optical Transmission and Sensing (OTS) terminal, the Optical Fiber Sensing and Processing (OSM) module, the Differential Protection Unit (DPU), and the Edge Collaborative Processing (ECN) node. The OTS connects to the power distribution fiber via a 1×2 optical coupler, responsible for transmitting combined optical signals into the fiber and receiving reverse Rayleigh scattering signals. The OSM is co-located with the OTS, receiving the scattering signals forwarded by the OTS for time and frequency domain analysis. The DPU has a data exchange channel with the OTS, used to collect local current data and transmit it to the other end via the OTS, while simultaneously receiving trip or blockage commands from the ECN to execute exit actions. The ECN maintains communication connections with both the OTS and DPU at each end, aggregating current data from both ends and overall physical state parameters for fusion and determination. Figure 1 The diagram also shows the PTP clock synchronization link, indicating that high-precision time synchronization is achieved between the OTS terminals via the IEEE 1588 protocol to ensure the synchronization of current sampling at both ends.

[0028] It should be noted that in the above system architecture, the hardware configuration of the optical sensing integrated terminal (OTS) can also include a wavelength locking unit. This unit locks the communication optical signal to a wavelength of 1550 nm and the probe optical signal to a wavelength of 1625 nm, with a wavelength interval of no less than 30 nm. This ensures sufficient wavelength isolation when the communication and probe optical signals are combined and transmitted in the same optical fiber, preventing crosstalk between them. Furthermore, the 1×2 type optical coupler integrated within the OTS controls its insertion loss to below 0.3 dB when performing multiplexing and demultiplexing functions, ensuring that the transmission quality of the optical signal is not significantly affected.

[0029] It should be noted that the optical time-domain reflectometry (OTDR) signal processing unit built into the optical fiber sensing and processing module (OSM) has a sampling rate of no less than 1 GSps to ensure the accuracy of acquiring the reverse Rayleigh scattering signal. At the same time, the OSM preprocesses the received scattering signal and then uploads it to the edge collaborative processing node (ECN). The delay introduced by the preprocessing process is controlled within a range of no more than 1 millisecond to ensure that the sensing data can participate in the differential protection decision in a timely manner and that the speed of protection action is not affected by the data processing delay.

[0030] It should be noted that the current acquisition unit integrated within the differential protection unit (DPU) has an accuracy of 0.2 class and a sampling rate of 2 kHz, which meets the requirements of differential protection for current data accuracy and sampling density. Furthermore, when transmitting current data to the peer or ECN via the OTS, the DPU can employ the national standard SM4 encryption module for encryption to ensure data transmission security, prevent data tampering or theft, and comply with the power industry's data security regulations.

[0031] It should be noted that the Edge Collaborative Processing Node (ECN) can be implemented using industrial-grade edge servers with a computing power of no less than 50 TOPS and memory of no less than 32GB to support high-intensity computing tasks such as real-time data fusion, communication optimization decision-making, and protection criterion calculation. The ECN integrates a data fusion unit, a communication optimization unit, and a protection decision-making unit, each responsible for different functional modules. The data fusion unit is responsible for spatiotemporal alignment and correlation of current data and physical state parameters; the communication optimization unit is responsible for generating communication parameter adjustment instructions based on physical state parameters; and the protection decision-making unit is responsible for performing differential current calculations and state type determinations. When performing the above data processing and decision-making operations, the overall data processing latency of the ECN is controlled to no more than 2 milliseconds to ensure that the entire differential protection decision-making process meets the distribution network's requirements for rapid action.

[0032] In this embodiment, the acquisition of the physical state parameters specifically involves: receiving the reverse Rayleigh scattering signal generated in the target power distribution fiber; wherein the reverse Rayleigh scattering signal is generated by sending a probe light signal to the target power distribution fiber; and performing time-domain analysis and frequency-domain analysis on the reverse Rayleigh scattering signal to calculate the physical state parameters.

[0033] In one specific embodiment, the aforementioned physical state parameters can be obtained as follows: In a power distribution fiber optic line performing differential protection, integrated optical sensing terminals are typically deployed at both the beginning and end of the line. These terminals possess both optical communication and optical detection capabilities. Taking the beginning end as an example, while sending differential current data to the other end, the integrated optical sensing terminal at the beginning end generates an additional narrow-pulse probe optical signal. This probe optical signal is combined with the communication optical signal carrying the current data using wavelength division multiplexing and then transmitted to the other end along the same power distribution fiber. During transmission, when the probe optical signal encounters the microscopic inhomogeneity of the fiber medium itself or refractive index disturbances along the fiber due to temperature changes or stress, it generates a back-propagating Rayleigh scattering signal. This scattered signal returns along the original path to the integrated optical sensing terminal at the beginning end. This terminal integrates an optical receiving module and an optical coupler, which can separate the returned scattered signal from the combined optical signal and send it to the fiber sensing processing module. This module has a built-in optical time-domain reflectometry signal processing unit, which can perform time-domain and frequency-domain analysis on the received reverse Rayleigh scattering signal.

[0034] Preferably, the communication optical signal generated by the integrated optical sensing terminal at the first end can be adopted as follows: Figure 3 The frame structure, Figure 3 This paper demonstrates the time-domain partitioning of a complete signal frame, with a single frame duration of 1 ms. The communication region occupies 800 μs, and the detection region occupies 200 μs, with no frame gap between the two regions to avoid time delay aggregation. The communication region uses OFDM modulation to carry the current data of the differential protection units at both ends, with a subcarrier spacing of 15 kHz and a subcarrier count of 1024. The detection region uses a narrow-pulse probe optical signal with a pulse width of 10 ns and a repetition frequency of 5 kHz. The communication and detection regions share the same distribution optical fiber via time-division multiplexing, and the optical power of the detection region is constrained to 0.05 to 0.1 times that of the communication region. This invention uses 0.08 times, ensuring that the probe light can excite a sufficiently strong Rayleigh scattering echo without causing perceptible crosstalk to the OFDM signal demodulation in the communication region.

[0035] Optionally, the specific configuration of the subcarrier spacing, number of subcarriers, and modulation order of OFDM modulation in the communication area can be flexibly configured according to the actual communication conditions of the line. For example, in a strong electromagnetic interference environment, 16QAM can be preferentially selected to ensure communication reliability; under good channel quality conditions, it can be switched to 64QAM to improve the data transmission rate. The optical transmit power can be dynamically adjusted in 0.5dBm steps within the range of 0 to 5dBm to adapt to different line loss conditions.

[0036] In this embodiment, the physical state parameters include line temperature distribution, line vibration parameters, and line stress parameters. The physical state parameters are obtained by performing time-domain and frequency-domain analysis on the reverse Rayleigh scattering signal, including: obtaining signal intensity variation and time delay fluctuation through time-domain analysis of the reverse Rayleigh scattering signal; calculating the line temperature distribution based on the signal intensity variation; and calculating the line vibration parameters based on the time delay fluctuation and OTDR positioning. The line vibration parameters include line vibration location and line vibration intensity. The line stress parameters are obtained by performing frequency-domain analysis of the reverse Rayleigh scattering signal to obtain phase fluctuation, and calculated based on the phase fluctuation.

[0037] In one specific embodiment, during time-domain analysis, the module records the relationship between the intensity of the scattered signal and time. The change in signal intensity reflects the temperature information at various points along the optical fiber. Because temperature changes can cause the molecular thermal motion to intensify or weaken, thereby changing the scattering efficiency, the module can calculate the temperature distribution of the entire line by comparing the real-time intensity with the reference light intensity of 25 degrees Celsius. At the same time, the module also records the time delay of the return of each scattering event. When vibration or disturbance occurs at a certain location, it will cause an instantaneous change in the optical path at that point, resulting in time delay fluctuation. Based on the time delay fluctuation and combined with the OTDR positioning principle, the module can calculate the specific location and intensity of the vibration event.

[0038] In one specific embodiment, during frequency domain analysis, the module extracts the phase information of the scattered signal. When the optical fiber is stretched or compressed by external force, its length and refractive index will change, thereby changing the phase of the scattered light. The module obtains the phase fluctuation amount through coherent detection and calculates the stress distribution along the optical fiber based on the phase fluctuation amount. This stress distribution can be used to determine whether the line is subjected to abnormal loads, such as icing, settlement, or external scraping.

[0039] Preferably, the temperature coefficient k used in the temperature calculation process is 2.5×10². This coefficient is obtained through experimental calibration based on the linear relationship between Rayleigh scattering intensity and temperature. There may be slight differences under different fiber types and wavelengths. In actual deployment, this coefficient can be calibrated on-site to further improve the temperature measurement accuracy.

[0040] Preferably, during the ice thickness calculation process, the stress calculation threshold is set to 50 MPa. When the stress borne by the optical fiber exceeds this threshold, it is considered abnormal, thus triggering further calculation of the ice thickness. The ice thickness conversion coefficient β is set to 0.15, which is used to convert the phase fluctuation into a millimeter value of ice thickness. In practical applications, this coefficient can be adaptively modified according to the type of optical fiber and the structure of the line.

[0041] Preferably, the time delay fluctuation threshold in vibration event determination is set to 5 nanoseconds. When the time delay fluctuation reaches or exceeds this value, it is determined to be abnormal vibration. Subsequently, the location of the vibration is determined by OTDR positioning technology, with a positioning accuracy of no more than 10 meters. This threshold and positioning accuracy can meet the requirements of power distribution networks for the detection and positioning of typical vibration events such as tree obstruction and external damage.

[0042] For a clearer explanation of the above-described process for solving the reverse Rayleigh scattering signal, please refer to [link to documentation]. Figure 4 .

[0043] It should be noted that, since both the first and second ends are equipped with the aforementioned integrated optical sensing terminal and fiber optic sensing processing module, both ends can independently provide reverse Rayleigh scattering signals to their respective fiber optic sensing processing modules. Therefore, the edge collaborative processing node can simultaneously obtain the physical state parameters of the line sensed from two directions, thereby achieving complete coverage of the physical state of the entire line.

[0044] Preferably, the probe optical signal adopts a narrow pulse with a width of 10 nanoseconds and a repetition frequency of 5 kHz, and its optical power is set to 0.05 to 0.1 times the communication optical power. This ensures that the scattered signal has sufficient intensity for calculation and does not cause perceptible interference to the normal reception and demodulation of the communication optical signal. The communication optical signal operates at a wavelength of 1550 nanometers, and the probe optical signal operates at a wavelength of 1625 nanometers. The two are combined and transmitted by wavelength division multiplexing with a wavelength interval of not less than 30 nanometers, which further ensures that the two do not crosstalk each other in the same optical fiber.

[0045] Preferably, in addition to sharing the same optical fiber using time-division multiplexing, the communication optical signal and the probe optical signal can also be further isolated in the same optical fiber using wavelength-division multiplexing. That is, the communication light operates at a wavelength of 1550 nanometers and the probe light operates at a wavelength of 1625 nanometers, with a wavelength interval of 75 nanometers (not less than 30 nanometers). With the wavelength locking unit inside the OTS, it is ensured that the two signals will not be confused during multiplexing and demultiplexing.

[0046] It should be noted that after the above physical state parameters are calculated by the fiber optic sensing and processing module, they are sent to the edge collaborative processing node through the internal data interface for subsequent differential current fusion judgment.

[0047] S102, based on the first current data, the second current data, and the physical state parameters, determine the state type of the target power distribution optical fiber; wherein, the state type includes physical fault state and communication link abnormal state; In this embodiment, determining the state type of the target power distribution fiber based on the first current data, the second current data, and physical state parameters includes: calculating a differential current value based on the first current data and the second current data; determining that the target power distribution fiber is in a physical fault state when the differential current value is greater than a preset differential current threshold and at least one state data in the physical state parameters is greater than the corresponding abnormal state threshold; and determining that the target power distribution fiber is in a communication link abnormal state when the differential current value is greater than the preset differential current threshold and none of the state data in the physical state parameters is greater than the corresponding abnormal state threshold.

[0048] In one specific embodiment, the process of determining the aforementioned state type is performed by an edge collaborative processing node. The edge collaborative processing node receives data from both ends of the line via a communication link: first current data from one end and second current data from the other end. Simultaneously, it receives physical state parameters uploaded by the fiber optic sensing and processing module. These physical state parameters include several data items reflecting the physical state of the line, such as temperature distribution, vibration parameters, and stress parameters.

[0049] After obtaining the above data, the edge collaborative processing node first calculates the differential current value based on the first current data and the second current data. The differential current value is the absolute value of the difference between the current sampling values ​​at both ends, which is used to preliminarily determine whether there is an electrical abnormality in the line.

[0050] Furthermore, the edge collaborative processing node compares the calculated differential current value with the preset differential current threshold, and at the same time compares each state data in the physical state parameters with its corresponding abnormal state threshold. Based on the combination of the two sets of comparison results, the node determines the state type of the target power distribution fiber.

[0051] If the differential current value is greater than the preset differential current threshold, it indicates that there is an over-limit phenomenon at the electrical level of the line. At this time, the edge collaborative processing node further checks the status data of each physical status parameter. When at least one status data in the physical status parameter is greater than its corresponding abnormal status threshold, such as the line temperature exceeding the preset temperature threshold, the vibration intensity exceeding the preset vibration threshold, or the stress value exceeding the preset stress threshold, it indicates that an abnormal change has indeed occurred in the physical world. The over-limit electrical quantity and the over-limit physical quantity corroborate each other, and the edge collaborative processing node determines the current state as a physical fault state.

[0052] Conversely, if the differential current value is greater than the preset differential current threshold, but none of the state data in the physical state parameters exceed their respective abnormal state thresholds, that is, all physical indicators such as temperature, vibration, and stress are within the normal range, it indicates that there is no abnormality in the physical world. The differential current exceeding the standard is not due to physical changes in the line itself, but rather to errors or delay jitter in the current data transmission process caused by communication link abnormalities. This results in a false differential current exceeding the standard after comparing the current data at both ends. Based on this, the edge collaborative processing node determines that the current state is an abnormal state of the communication link.

[0053] Through cross-verification of the two sets of independent evidence, the edge collaborative processing node can clearly distinguish the true cause of the differential current exceeding the standard, thereby providing a basis for generating correct control commands in the future and avoiding the problem of false tripping caused by the inability to distinguish between physical faults and communication anomalies in the existing technology.

[0054] S103, when it is determined that the target power distribution fiber is in a physical fault state or a communication link abnormal state, a corresponding control command is generated according to the state type, and the control command is sent to the execution end to control the execution end to perform the corresponding differential protection action; wherein, the control command includes an open trip command or a closed trip command.

[0055] In this embodiment, a corresponding control command is generated according to the state type, including: when it is determined that the target power distribution fiber is in a physical fault state, an open trip command is generated; when it is determined that the target power distribution fiber is in a communication link abnormal state, a block trip command and a communication parameter optimization command are generated.

[0056] In one specific embodiment, when the edge collaborative processing node determines that the current state is a physical fault state, it means that the two independent pieces of evidence—excessive differential current and abnormal physical state parameters—corroborate each other, indicating that a real physical fault has indeed occurred in the line. At this time, the edge collaborative processing node generates an open trip command and sends it to the differential protection unit. After receiving the command, the differential protection unit's internal protection criterion execution unit and trip output module will trigger actions within no more than 3 milliseconds, driving the circuit breaker to trip to isolate the fault area. To ensure that the fault handling effect is promptly confirmed, within 500 microseconds after issuing the trip command, the edge collaborative processing node will further instruct the optical sensing integrated terminal to increase the repetition frequency of the detection light from the conventional 5 kHz to 10 kHz, to monitor the physical state changes of the fault area at a higher frequency.

[0057] Preferably, when determining physical faults, for 10kV distribution lines, the differential current threshold I_set can be set to 5kA; the icing thickness threshold involved in physical fault determination is set to 20mm, meaning that when the icing thickness reaches or exceeds 20mm, it is determined as a physical fault in conjunction with the current exceeding the limit. The above thresholds can be adjusted accordingly based on changes in line rated parameters, load characteristics, and operating environment. Different threshold configurations can be adopted for application scenarios with different voltage levels or different line types.

[0058] In one specific embodiment, the situation is completely different when the edge collaborative processing node determines that the current state is an abnormal communication link state. At this time, although the differential current value exceeds the limit, all data in the physical state parameters are within the normal range, indicating that the current exceedance is not due to physical changes in the line itself, but rather to errors or time delay jitter during current data transmission caused by the abnormal communication link, resulting in a false differential current exceedance after comparing the current data at both ends. In response to this situation, the edge collaborative processing node generates a blocking trip command and sends it to the differential protection unit to prohibit the trip output action and avoid unnecessary power outages caused by communication interference. Simultaneously, the edge collaborative processing node also generates a communication parameter optimization command and sends it to the integrated optical sensing terminal.

[0059] Preferably, after a fault trip, the system can enter a high-frequency monitoring mode. Within 500 microseconds of issuing the trip command, the edge collaborative processing node instructs the integrated optical sensing terminal to increase the repetition frequency of the probe light from the normal 5 kHz to 10 kHz, continuously monitoring the physical state changes of the fault area with a higher sampling density, thereby assessing the fault handling effect in real time. After confirming that the fault has been completely eliminated, the system then restores the detection frequency to 5 kHz.

[0060] In this embodiment, the generation of the communication optimization instruction includes: generating a parameter adjustment instruction for the communication signal based on the physical state parameters and a preset adjustment threshold; wherein the parameter adjustment instruction includes at least one of the following: a modulation order adjustment instruction or a transmit power adjustment instruction.

[0061] In one specific embodiment, when the edge collaborative processing node determines that the target power distribution fiber is in an abnormal communication link state, in addition to generating a blocking trip command to avoid malfunction, it also simultaneously generates a communication parameter optimization command and sends it to the integrated optical sensing terminal. This communication parameter optimization command is not a fixed, single adjustment command, but is dynamically generated based on the comparison results between the current physical state parameters and preset adjustment thresholds. Its purpose is to take corresponding communication parameter adjustment measures for the physical environmental factors causing the communication link abnormality, in order to suppress or eliminate communication interference. Specifically, the physical state parameters continuously calculated by the fiber sensing processing module include temperature distribution data and vibration parameter data along the line. The edge collaborative processing node compares these data with their respective preset adjustment thresholds and selects to generate at least one of a modulation order adjustment command or a transmit power adjustment command based on the comparison results.

[0062] In one specific embodiment, regarding the adjustment of the modulation order, when the sensed line temperature reaches or exceeds 40 degrees Celsius, the high-temperature environment leads to increased fiber transmission loss and a decrease in the signal-to-noise ratio. In this case, the edge collaborative processing node generates a modulation order adjustment command, instructing the integrated optical sensing terminal to switch the modulation order of the communication area from 64QAM to 16QQAM. The lower-order modulation method has lower requirements for signal quality, stronger anti-interference capabilities, and can maintain communication reliability even under conditions where high temperatures cause channel quality degradation.

[0063] In one specific embodiment, regarding the adjustment of transmit power, when the sensed line temperature is below or equal to -10 degrees Celsius, the low temperature will cause increased fiber loss, resulting in accelerated signal attenuation at the receiving end. In this case, the edge collaborative processing node generates a transmit power adjustment command, instructing the optical sensing integrated terminal to increase the optical transmit power by 1 dB / mW to compensate for the fiber loss caused by the low temperature. When abnormal vibration is sensed, the vibration will cause increased fiber microbending loss, leading to signal attenuation. In this case, the edge collaborative processing node also generates a transmit power adjustment command, instructing the optical sensing integrated terminal to temporarily increase the optical transmit power by 0.5 dB / mW to avoid signal attenuation. The above adjustments are all temporary measures. Once the corresponding physical state parameters return to the normal range, the edge collaborative processing node will generate a reset command, instructing the optical sensing integrated terminal to restore the default communication parameter configuration.

[0064] Preferably, when the optical sensing integrated terminal responds to the above instructions, the adjustment step size of the optical emission power is 0.5 dBmW, and the modulation order is switched between 16QAM and 64QAM. These two adjustment methods can be executed individually or in combination according to the actual working conditions.

[0065] In this embodiment, the method further includes: continuously receiving the physical state parameters of the target power distribution fiber, and determining whether each state data in the physical state parameters has been restored to the corresponding preset normal state range; when it is determined that each state data has been restored to the corresponding preset normal state range, generating a reset command and sending it to the execution end.

[0066] In one specific embodiment, after the edge collaborative processing node completes the issuance of the trip command or the blocking trip command, the entire system does not stop working at this point, but enters a stage of continuous monitoring and waiting for recovery.

[0067] Specifically, the fiber optic sensing and processing module remains operational throughout the fault handling process, continuously receiving the reverse Rayleigh scattering signal generated by the probe light signal and performing time-domain and frequency-domain analysis. It continuously calculates the physical state parameters along the target power distribution fiber, including temperature distribution, vibration parameters, and stress parameters, and uploads this data to the edge collaborative processing node. The edge collaborative processing node synchronously receives these physical state parameters and compares each data point with its corresponding preset normal state range to determine if each parameter has returned to an acceptable normal range. When the edge collaborative processing node confirms that all physical state parameters have returned to their corresponding preset normal state ranges—that is, the temperature has returned to the normal range, the vibration parameter has fallen below the vibration threshold, and the stress parameter has returned to the normal stress range—it indicates that the physical cause of the previous abnormal state has been eliminated. In this scenario, the edge collaborative processing node generates a reset command and sends it to the execution end. This reset command instructs the integrated optical sensing terminal to restore its default operating parameters, such as restoring the probe light frequency from the post-fault boosted 10 kHz to the normal 5 kHz, and restoring the modulation order of the communication area to 64QAM. Simultaneously, it instructs the differential protection unit to reset its protection state, allowing the system to re-enter normal operation monitoring mode. Thus, the entire closed loop, from anomaly identification, state determination, control command generation to recovery and reset, is completed.

[0068] Optionally, the physical state parameters proposed in this invention can include not only temperature distribution, vibration parameters, and stress parameters, but can also be extended to more sensing dimensions such as fiber optic loss monitoring and tower tilt early warning through software upgrades. These extended functions can be implemented by updating the algorithm modules of the edge collaborative processing nodes without replacing the hardware devices, and have good scalability and future adaptability.

[0069] Preferably, if some state data is recovered while other state data remains in the abnormal range, the edge collaborative processing node continues to maintain the monitoring state without generating a reset command, ensuring that the system will not be erroneously restored before all anomalies are eliminated.

[0070] Optionally, when generating a reset command, the edge collaborative processing node can require all physical state data to remain normal for a preset duration before triggering the reset action. For example, the continuous monitoring time can be set to 5 seconds. If all state data does not exceed the normal range again during this period, the anomaly is determined to have been completely eliminated and a reset command is generated to avoid frequent system resets due to instantaneous fluctuations.

[0071] Preferably, the components involved in the embodiments of the present invention can use the IEC 61850 standard protocol for data interaction. Differential current data and physical state parameters follow the sampling value SV and general object-oriented substation event GOOSE and other communication specifications defined by the standard during transmission, thereby achieving seamless compatibility with existing distribution network automation systems and protection equipment.

[0072] Preferably, a complete workflow of the present invention can be understood with reference to the following specific implementation scenario. Taking a 10-kilometer-long 10kV distribution network line as an example, the line uses ADSS single-mode optical cable as the distribution optical fiber, and optical sensing integrated terminals and differential protection units are deployed at both ends of the line. During the system initialization phase, each component performs self-test after power-on. The differential protection units at both ends complete time synchronization through the IEEE 1588 PTP protocol, with a synchronization accuracy of 0.3 microseconds. The optical sensing integrated terminal configures waveform parameters and locks the working wavelength. The fiber optic sensing and processing module is calibrated based on the scattered light intensity at 25 degrees Celsius. During normal operation, the optical sensing integrated terminal continuously emits combined optical signals, and the differential protection unit collects current data every 500 microseconds. For example, the local current is 200 amps, the remote current is 198 amps, and the differential current value is 2 amps, which is much less than the preset threshold. At the same time, the fiber optic sensing and processing module calculates that the line temperature is 26 degrees Celsius, there is no icing, and there is no abnormal vibration. The edge collaborative processing node determines that it is in normal operating condition based on this. During the fault handling phase, tree intrusion caused a phase-to-phase short circuit, resulting in a sudden surge in the local current to 5.8 kA and a drop in the remote current to 0.8 kA. The differential current reached 5 kA, exceeding the preset threshold. Simultaneously, the fiber optic sensing module detected a delay fluctuation of 8 nanoseconds, exceeding the abnormal threshold of 5 nanoseconds, and determined the fault location to be 6.2 kilometers away from the local end using OTDR positioning. Within 1.5 milliseconds, the edge collaborative processing node determined that the fault was a real physical fault, generated an open trip command, and issued it. The differential protection unit executed the trip action within 2.8 milliseconds, with a total delay of 7.2 milliseconds from the fault occurrence to the trip completion. During the recovery phase, after the tree intrusion was removed, the fiber optic sensing module detected that the vibration parameters had returned to the normal range. After confirming that all physical status data were normal, the edge collaborative processing node generated a reset command, instructing the integrated optical sensing terminal to restore the detection frequency from 10 kHz to 5 kHz and the communication modulation order to 64QAM. At the same time, it instructed the differential protection unit to reset the protection state, and the system re-entered normal operation monitoring mode. The complete process for each of the above steps can be found in [reference]. Figure 5 As shown.

[0073] It should be noted that the power distribution optical fiber involved in this invention can be selected from OPGW optical fiber composite overhead ground wire or ADSS all-dielectric self-supporting optical cable. These two types of optical cables have been deployed on a large scale in the distribution network. This invention can directly reuse existing optical cable resources without laying additional dedicated sensing optical fibers, thereby making full use of existing infrastructure and reducing system construction costs.

[0074] This invention provides basic data for differential current calculation by acquiring first and second current data, and obtains physical state parameters through reverse Rayleigh scattering signals. These physical state parameters originate from Rayleigh scattering of the optical fiber itself and are a direct mapping of the physical world (temperature, stress, vibration), unaffected by communication link anomalies such as communication errors and delay jitter. This provides independent verification evidence for distinguishing between true and false differential current exceedances. By fusing electrical evidence (current data) and physical evidence (physical state parameters) for cross-validation, the output results are differentiated into two different states at the criterion level. Based on the state type, corresponding trip commands are generated, thereby reducing the error rate of tripping actions during differential protection.

[0075] Compared with existing technologies, this invention constructs a complete framework for parallel acquisition of dual-dimensional data, fusion determination of state types, and differentiated output of control commands. At the criterion level, it distinguishes the output results into two distinct states: physical faults and communication link anomalies. This framework directly breaks the unidirectional logic of tripping upon exceeding limits in traditional solutions, enabling the system to differentiate between genuine physical faults and false exceedances in the information world, thereby executing the corresponding correct tripping operation. This solves the problem that existing differential protection technologies are prone to erroneous tripping actions due to the difficulty in distinguishing between physical faults and communication link anomalies at the differential current level, significantly improving the power supply reliability of the distribution network.

[0076] Example 2: like Figure 6 As shown, this embodiment provides a differential protection device based on power distribution fiber optic cable, including a data acquisition module 201, a status type determination module 202, and a differential protection control module 203, wherein... The data acquisition module 201 is used to acquire first current data, second current data, and physical state parameters of the target power distribution optical fiber; wherein, the first current data and second current data are obtained by modulating the terminals at different locations of the target power distribution optical fiber respectively; the physical state parameters are obtained by solving the reverse Rayleigh scattering signal on the target power distribution optical fiber; the physical state parameters include several state data items. In this embodiment, the acquisition of the physical state parameters specifically involves: receiving the reverse Rayleigh scattering signal generated in the target power distribution fiber; wherein the reverse Rayleigh scattering signal is generated by sending a probe light signal to the target power distribution fiber; and performing time-domain analysis and frequency-domain analysis on the reverse Rayleigh scattering signal to calculate the physical state parameters.

[0077] In one specific embodiment, the aforementioned physical state parameters can be obtained as follows: In a power distribution fiber optic line performing differential protection, integrated optical sensing terminals are typically deployed at both the beginning and end of the line. These terminals possess both optical communication and optical detection capabilities. Taking the beginning end as an example, while sending differential current data to the other end, the integrated optical sensing terminal at the beginning end generates an additional narrow-pulse probe optical signal. This probe optical signal is combined with the communication optical signal carrying the current data using wavelength division multiplexing and then transmitted to the other end along the same power distribution fiber. During transmission, when the probe optical signal encounters the microscopic inhomogeneity of the fiber medium itself or refractive index disturbances along the fiber due to temperature changes or stress, it generates a back-propagating Rayleigh scattering signal. This scattered signal returns along the original path to the integrated optical sensing terminal at the beginning end. This terminal integrates an optical receiving module and an optical coupler, which can separate the returned scattered signal from the combined optical signal and send it to the fiber sensing processing module. This module has a built-in optical time-domain reflectometry signal processing unit, which can perform time-domain and frequency-domain analysis on the received reverse Rayleigh scattering signal.

[0078] Optionally, the specific configuration of the subcarrier spacing, number of subcarriers, and modulation order of OFDM modulation in the communication area can be flexibly configured according to the actual communication conditions of the line. For example, in a strong electromagnetic interference environment, 16QAM can be preferentially selected to ensure communication reliability; under good channel quality conditions, it can be switched to 64QAM to improve the data transmission rate. The optical transmit power can be dynamically adjusted in 0.5dBm steps within the range of 0 to 5dBm to adapt to different line loss conditions.

[0079] In this embodiment, the physical state parameters include line temperature distribution, line vibration parameters, and line stress parameters. The physical state parameters are obtained by performing time-domain and frequency-domain analysis on the reverse Rayleigh scattering signal, including: obtaining signal intensity variation and time delay fluctuation through time-domain analysis of the reverse Rayleigh scattering signal; calculating the line temperature distribution based on the signal intensity variation; and calculating the line vibration parameters based on the time delay fluctuation and OTDR positioning. The line vibration parameters include line vibration location and line vibration intensity. The line stress parameters are obtained by performing frequency-domain analysis of the reverse Rayleigh scattering signal to obtain phase fluctuation, and calculated based on the phase fluctuation.

[0080] In one specific embodiment, during time-domain analysis, the module records the relationship between the intensity of the scattered signal and time. The change in signal intensity reflects the temperature information at various points along the optical fiber. Because temperature changes can cause the molecular thermal motion to intensify or weaken, thereby changing the scattering efficiency, the module can calculate the temperature distribution of the entire line by comparing the real-time intensity with the reference light intensity of 25 degrees Celsius. At the same time, the module also records the time delay of the return of each scattering event. When vibration or disturbance occurs at a certain location, it will cause an instantaneous change in the optical path at that point, resulting in time delay fluctuation. Based on the time delay fluctuation and combined with the OTDR positioning principle, the module can calculate the specific location and intensity of the vibration event.

[0081] In one specific embodiment, during frequency domain analysis, the module extracts the phase information of the scattered signal. When the optical fiber is stretched or compressed by external force, its length and refractive index will change, thereby changing the phase of the scattered light. The module obtains the phase fluctuation amount through coherent detection and calculates the stress distribution along the optical fiber based on the phase fluctuation amount. This stress distribution can be used to determine whether the line is subjected to abnormal loads, such as icing, settlement, or external scraping.

[0082] Preferably, the probe optical signal adopts a narrow pulse with a width of 10 nanoseconds and a repetition frequency of 5 kHz, and its optical power is set to 0.05 to 0.1 times the communication optical power. This ensures that the scattered signal has sufficient intensity for calculation and does not cause perceptible interference to the normal reception and demodulation of the communication optical signal. The communication optical signal operates at a wavelength of 1550 nanometers, and the probe optical signal operates at a wavelength of 1625 nanometers. The two are combined and transmitted by wavelength division multiplexing with a wavelength interval of not less than 30 nanometers, which further ensures that the two do not crosstalk each other in the same optical fiber.

[0083] Preferably, in addition to sharing the same optical fiber using time-division multiplexing, the communication optical signal and the probe optical signal can also be further isolated in the same optical fiber using wavelength-division multiplexing. That is, the communication light operates at a wavelength of 1550 nanometers and the probe light operates at a wavelength of 1625 nanometers, with a wavelength interval of 75 nanometers (not less than 30 nanometers). With the wavelength locking unit inside the OTS, it is ensured that the two signals will not be confused during multiplexing and demultiplexing.

[0084] The state type determination module 202 is used to determine the state type of the target power distribution optical fiber based on the first current data, the second current data, and the physical state parameters; wherein, the state type includes physical fault state and communication link abnormal state. In this embodiment, the state type determination module 202 determines the state type of the target power distribution optical fiber based on the first current data, the second current data, and the physical state parameters. This includes: the state type determination module 202 calculates a differential current value based on the first current data and the second current data; when the differential current value is greater than a preset differential current threshold and at least one of the physical state parameters is greater than the corresponding abnormal state threshold, the target power distribution optical fiber is determined to be in a physical fault state; when the differential current value is greater than the preset differential current threshold and none of the physical state parameters is greater than the corresponding abnormal state threshold, the target power distribution optical fiber is determined to be in a communication link abnormal state.

[0085] In one specific embodiment, the process of determining the aforementioned state type is performed by an edge collaborative processing node. The edge collaborative processing node receives data from both ends of the line via a communication link: first current data from one end and second current data from the other end. Simultaneously, it receives physical state parameters uploaded by the fiber optic sensing and processing module. These physical state parameters include several data items reflecting the physical state of the line, such as temperature distribution, vibration parameters, and stress parameters.

[0086] After obtaining the above data, the edge collaborative processing node first calculates the differential current value based on the first current data and the second current data. The differential current value is the absolute value of the difference between the current sampling values ​​at both ends, which is used to preliminarily determine whether there is an electrical abnormality in the line.

[0087] Furthermore, the edge collaborative processing node compares the calculated differential current value with the preset differential current threshold, and at the same time compares each state data in the physical state parameters with its corresponding abnormal state threshold. Based on the combination of the two sets of comparison results, the node determines the state type of the target power distribution fiber.

[0088] If the differential current value is greater than the preset differential current threshold, it indicates that there is an over-limit phenomenon at the electrical level of the line. At this time, the edge collaborative processing node further checks the status data of each physical status parameter. When at least one status data in the physical status parameter is greater than its corresponding abnormal status threshold, such as the line temperature exceeding the preset temperature threshold, the vibration intensity exceeding the preset vibration threshold, or the stress value exceeding the preset stress threshold, it indicates that an abnormal change has indeed occurred in the physical world. The over-limit electrical quantity and the over-limit physical quantity corroborate each other, and the edge collaborative processing node determines the current state as a physical fault state.

[0089] Conversely, if the differential current value is greater than the preset differential current threshold, but none of the state data in the physical state parameters exceed their respective abnormal state thresholds, that is, all physical indicators such as temperature, vibration, and stress are within the normal range, it indicates that there is no abnormality in the physical world. The differential current exceeding the standard is not due to physical changes in the line itself, but rather to errors or delay jitter in the current data transmission process caused by communication link abnormalities. This results in a false differential current exceeding the standard after comparing the current data at both ends. Based on this, the edge collaborative processing node determines that the current state is an abnormal state of the communication link.

[0090] Through cross-verification of the two sets of independent evidence, the edge collaborative processing node can clearly distinguish the true cause of the differential current exceeding the standard, thereby providing a basis for generating correct control commands in the future and avoiding the problem of false tripping caused by the inability to distinguish between physical faults and communication anomalies in the existing technology.

[0091] The differential protection control module 203 is used to generate a corresponding control command according to the state type when it is determined that the target power distribution fiber is in a physical fault state or a communication link abnormal state, and send the control command to the execution end to control the execution end to perform the corresponding differential protection action; wherein, the control command includes an open trip command or a blocked trip command.

[0092] In this embodiment, the differential protection control module 203 generates corresponding control instructions based on the state type, including: generating an open trip instruction when it is determined that the target power distribution fiber is in a physical fault state; and generating a blocking trip instruction and a communication parameter optimization instruction when it is determined that the target power distribution fiber is in a communication link abnormal state.

[0093] In one specific embodiment, when the edge collaborative processing node determines that the current state is a physical fault state, it means that the two independent pieces of evidence—excessive differential current and abnormal physical state parameters—corroborate each other, indicating that a real physical fault has indeed occurred in the line. At this time, the edge collaborative processing node generates an open trip command and sends it to the differential protection unit. After receiving the command, the differential protection unit's internal protection criterion execution unit and trip output module will trigger actions within no more than 3 milliseconds, driving the circuit breaker to trip to isolate the fault area. To ensure that the fault handling effect is promptly confirmed, within 500 microseconds after issuing the trip command, the edge collaborative processing node will further instruct the optical sensing integrated terminal to increase the repetition frequency of the detection light from the conventional 5 kHz to 10 kHz, to monitor the physical state changes of the fault area at a higher frequency.

[0094] Preferably, when determining physical faults, for 10kV distribution lines, the differential current threshold I_set can be set to 5kA; the icing thickness threshold involved in physical fault determination is set to 20mm, meaning that when the icing thickness reaches or exceeds 20mm, it is determined as a physical fault in conjunction with the current exceeding the limit. The above thresholds can be adjusted accordingly based on changes in line rated parameters, load characteristics, and operating environment, allowing for differentiated threshold configurations in application scenarios with different voltage levels or line types.

[0095] In one specific embodiment, the situation is completely different when the edge collaborative processing node determines that the current state is an abnormal communication link state. At this time, although the differential current value exceeds the limit, all data in the physical state parameters are within the normal range, indicating that the current exceedance is not due to physical changes in the line itself, but rather to errors or time delay jitter during current data transmission caused by the abnormal communication link, resulting in a false differential current exceedance after comparing the current data at both ends. In response to this situation, the edge collaborative processing node generates a blocking trip command and sends it to the differential protection unit to prohibit the trip output action and avoid unwarranted power outages caused by communication interference. Simultaneously, the edge collaborative processing node also generates a communication parameter optimization command and sends it to the integrated optical sensing terminal.

[0096] Preferably, after a fault trip, the system can enter a high-frequency monitoring mode. Within 500 microseconds of issuing the trip command, the edge collaborative processing node instructs the integrated optical sensing terminal to increase the repetition frequency of the probe light from the normal 5 kHz to 10 kHz, continuously monitoring the physical state changes of the fault area with a higher sampling density, thereby assessing the fault handling effect in real time. After confirming that the fault has been completely eliminated, the system then restores the detection frequency to 5 kHz.

[0097] In this embodiment, the generation of the communication optimization instruction includes: generating a parameter adjustment instruction for the communication signal based on the physical state parameters and a preset adjustment threshold; wherein the parameter adjustment instruction includes at least one of the following: a modulation order adjustment instruction or a transmit power adjustment instruction.

[0098] In one specific embodiment, when the edge collaborative processing node determines that the target power distribution fiber is in an abnormal communication link state, in addition to generating a blocking trip command to avoid malfunction, it also simultaneously generates a communication parameter optimization command and sends it to the integrated optical sensing terminal. This communication parameter optimization command is not a fixed, single adjustment command, but is dynamically generated based on the comparison results between the current physical state parameters and preset adjustment thresholds. Its purpose is to take corresponding communication parameter adjustment measures for the physical environmental factors causing the communication link abnormality, in order to suppress or eliminate communication interference. Specifically, the physical state parameters continuously calculated by the fiber sensing processing module include temperature distribution data and vibration parameter data along the line. The edge collaborative processing node compares these data with their respective preset adjustment thresholds and selects to generate at least one of a modulation order adjustment command or a transmit power adjustment command based on the comparison results.

[0099] In one specific embodiment, regarding the adjustment of the modulation order, when the sensed line temperature reaches or exceeds 40 degrees Celsius, the high-temperature environment leads to increased fiber transmission loss and a decrease in the signal-to-noise ratio. In this case, the edge collaborative processing node generates a modulation order adjustment command, instructing the integrated optical sensing terminal to switch the modulation order of the communication area from 64QAM to 16QQAM. The lower-order modulation method has lower requirements for signal quality, stronger anti-interference capabilities, and can maintain communication reliability even under conditions where high temperatures cause channel quality degradation.

[0100] In one specific embodiment, regarding the adjustment of transmit power, when the sensed line temperature is below or equal to -10 degrees Celsius, the low temperature will cause increased fiber loss, resulting in accelerated signal attenuation at the receiving end. In this case, the edge collaborative processing node generates a transmit power adjustment command, instructing the optical sensing integrated terminal to increase the optical transmit power by 1 dB / mW to compensate for the fiber loss caused by the low temperature. When abnormal vibration is sensed, the vibration will cause increased fiber microbending loss, leading to signal attenuation. In this case, the edge collaborative processing node also generates a transmit power adjustment command, instructing the optical sensing integrated terminal to temporarily increase the optical transmit power by 0.5 dB / mW to avoid signal attenuation. The above adjustments are all temporary measures. Once the corresponding physical state parameters return to the normal range, the edge collaborative processing node will generate a reset command, instructing the optical sensing integrated terminal to restore the default communication parameter configuration.

[0101] Preferably, when the optical sensing integrated terminal responds to the above instructions, the adjustment step size of the optical emission power is 0.5 dBmW, and the modulation order is switched between 16QAM and 64QAM. These two adjustment methods can be executed individually or in combination according to the actual working conditions.

[0102] In this embodiment, the method further includes: continuously receiving the physical state parameters of the target power distribution fiber, and determining whether each state data in the physical state parameters has been restored to the corresponding preset normal state range; when it is determined that each state data has been restored to the corresponding preset normal state range, generating a reset command and sending it to the execution end.

[0103] In one specific embodiment, after the edge collaborative processing node completes the issuance of the trip command or the blocking trip command, the entire system does not stop working at this point, but enters a stage of continuous monitoring and waiting for recovery.

[0104] Specifically, the fiber optic sensing and processing module remains operational throughout the fault handling process, continuously receiving the reverse Rayleigh scattering signal generated by the probe light signal and performing time-domain and frequency-domain analysis. It continuously calculates the physical state parameters along the target power distribution fiber, including temperature distribution, vibration parameters, and stress parameters, and uploads this data to the edge collaborative processing node. The edge collaborative processing node synchronously receives these physical state parameters and compares each data point with its corresponding preset normal state range to determine if each parameter has returned to an acceptable normal range. When the edge collaborative processing node confirms that all physical state parameters have returned to their corresponding preset normal state ranges—that is, the temperature has returned to the normal range, the vibration parameter has fallen below the vibration threshold, and the stress parameter has returned to the normal stress range—it indicates that the physical cause of the previous abnormal state has been eliminated. In this scenario, the edge collaborative processing node generates a reset command and sends it to the execution end. This reset command instructs the integrated optical sensing terminal to restore its default operating parameters, such as restoring the probe light frequency from the post-fault boosted 10 kHz to the normal 5 kHz, and restoring the modulation order of the communication area to 64QAM. Simultaneously, it instructs the differential protection unit to reset its protection state, allowing the system to re-enter normal operation monitoring mode. Thus, the entire closed loop, from anomaly identification, state determination, control command generation to recovery and reset, is completed.

[0105] Optionally, the physical state parameters proposed in this invention can include not only temperature distribution, vibration parameters, and stress parameters, but can also be extended to more sensing dimensions such as fiber optic loss monitoring and tower tilt early warning through software upgrades. These extended functions can be implemented by updating the algorithm modules of the edge collaborative processing nodes without replacing the hardware devices, and have good scalability and future adaptability.

[0106] Preferably, if some state data is recovered while other state data remains in the abnormal range, the edge collaborative processing node continues to maintain the monitoring state without generating a reset command, ensuring that the system will not be erroneously restored before all anomalies are eliminated.

[0107] Optionally, when generating a reset command, the edge collaborative processing node can require all physical state data to remain normal for a preset duration before triggering the reset action. For example, the continuous monitoring time can be set to 5 seconds. If all state data does not exceed the normal range again during this period, the anomaly is determined to have been completely eliminated and a reset command is generated to avoid frequent system resets due to instantaneous fluctuations.

[0108] Preferably, the components involved in the embodiments of the present invention can use the IEC 61850 standard protocol for data interaction. Differential current data and physical state parameters follow the sampling value SV and general object-oriented substation event GOOSE and other communication specifications defined by the standard during transmission, thereby achieving seamless compatibility with existing distribution network automation systems and protection equipment.

[0109] It should be noted that the power distribution optical fiber involved in this invention can be selected from OPGW optical fiber composite overhead ground wire or ADSS all-dielectric self-supporting optical cable. These two types of optical cables have been deployed on a large scale in the distribution network. This invention can directly reuse existing optical cable resources without laying additional dedicated sensing optical fibers, thereby making full use of existing infrastructure and reducing system construction costs.

[0110] For a more detailed explanation of the working principle and procedures of this embodiment, please refer to the relevant description in Embodiment 1.

[0111] In this embodiment of the invention, the data acquisition module 201 acquires first current data and second current data to provide basic data for differential current calculation. Physical state parameters are obtained through reverse Rayleigh scattering signals. These physical state parameters originate from Rayleigh scattering of the optical fiber itself and are a direct mapping of the physical world (temperature, stress, vibration), unaffected by communication link anomalies such as communication errors and latency jitter. This provides independent verification evidence for distinguishing between true and false differential current exceedances. The state type determination module 202 cross-validates electrical evidence (current data) and physical evidence (physical state parameters), thereby distinguishing the output results into two different states at the criterion level. The differential protection control module 203 generates corresponding trip commands based on the state type, thereby reducing the error rate of tripping actions during differential protection.

[0112] Example 3: This embodiment provides a terminal device, including: a processor, a memory, a communication interface, and a communication bus, wherein the processor, the memory, and the communication interface communicate with each other through the communication bus; The memory is used to store at least one executable instruction that causes the processor to perform the operation of the differential protection method based on power distribution fiber as described in any of the above.

[0113] Example 4: This invention provides a computer-readable storage medium including a stored computer program, wherein the computer program, when running, controls the device or apparatus containing the computer-readable storage medium to perform the differential protection method based on power distribution optical fiber as described in any of the preceding claims.

[0114] Those skilled in the art will understand that all or part of the processes in the above embodiments can be implemented by a computer program instructing related hardware. The program can be stored in a computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. The storage medium can be a magnetic disk, optical disk, read-only memory (ROM), or random access memory (RAM), etc.

[0115] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the scope of protection of the present invention. In particular, it should be noted that any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention for those skilled in the art.

Claims

1. A method for differential protection based on power distribution optical fibers, characterized in that, include: The method involves acquiring first current data, second current data, and physical state parameters of the target power distribution fiber; wherein the first current data and second current data are obtained by modulating the terminals at different locations of the target power distribution fiber; the physical state parameters are obtained by solving the reverse Rayleigh scattering signal on the target power distribution fiber; and the physical state parameters include several state data items. Based on the first current data, the second current data, and the physical state parameters, the state type of the target power distribution fiber is determined; wherein, the state type includes physical fault state and communication link abnormal state; When it is determined that the target power distribution fiber is in a physical fault state or a communication link abnormal state, a corresponding control command is generated according to the state type, and the control command is sent to the execution end to control the execution end to perform the corresponding differential protection action; wherein, the control command includes an open trip command or a blocked trip command.

2. A method for fiber optic based differential protection for power distribution as claimed in claim 1 wherein, Based on the first current data, the second current data, and physical state parameters, the state type of the target power distribution fiber is determined, including: Calculate the differential current value based on the first current data and the second current data; When the differential current value is greater than the preset differential current threshold and at least one of the physical state parameters is greater than the corresponding abnormal state threshold, the target power distribution fiber is determined to be in a physical fault state. When the differential current value is greater than the preset differential current threshold and none of the status data in the physical state parameters are greater than the corresponding abnormal state threshold, the target power distribution optical fiber is determined to be in an abnormal communication link state.

3. A power distribution fiber based differential protection method as claimed in claim 2, wherein, Based on the state type, generate corresponding control instructions, including: When it is determined that the target power distribution fiber is in a physical fault state, an open trip command is generated; When it is determined that the target power distribution fiber is in an abnormal communication link state, a blocking trip command and a communication parameter optimization command are generated.

4. A power distribution fiber based differential protection method as claimed in claim 2, wherein, The acquisition of the physical state parameters is specifically as follows: The reverse Rayleigh scattering signal generated in the target power distribution fiber is received; wherein the reverse Rayleigh scattering signal is generated by sending a probe light signal to the target power distribution fiber. The physical state parameters are obtained by performing time-domain and frequency-domain analysis on the reverse Rayleigh scattering signal.

5. A method for fiber optic based differential protection of a power distribution line as claimed in claim 4, wherein, The physical state parameters include line temperature distribution, line vibration parameters, and line stress parameters. Specifically, the physical state parameters are obtained by performing time-domain and frequency-domain analysis on the reverse Rayleigh scattering signal, including: By performing time-domain analysis on the reverse Rayleigh scattering signal, the signal intensity change and time delay fluctuation were obtained; The line temperature distribution is calculated based on the signal strength change. Based on the time delay fluctuation, combined with OTDR positioning, the line vibration parameters are calculated; wherein, the line vibration parameters include the line vibration location and the line vibration intensity. By performing frequency domain analysis on the reverse Rayleigh scattering signal, the phase fluctuation is obtained, and the line stress parameters are calculated based on the phase fluctuation.

6. A method for fiber optic based differential protection for power distribution as claimed in claim 3 wherein, The generation of the communication optimization instructions includes: Based on the physical state parameters and the preset adjustment threshold, a parameter adjustment instruction for the communication signal is generated; wherein, the parameter adjustment instruction includes at least one of the following: modulation order adjustment instruction or transmit power adjustment instruction.

7. The differential protection method based on power distribution optical fiber as described in claim 1, characterized in that, Also includes: The system continuously receives the physical state parameters of the target power distribution fiber and determines whether each state data in the physical state parameters has been restored to the corresponding preset normal state range. When it is determined that all the state data have been restored to the corresponding preset normal state range, a reset command is generated and sent to the execution terminal.

8. A differential protection device based on power distribution optical fiber, characterized in that, It includes a data acquisition module, a status type determination module, and a differential protection control module, among which, The data acquisition module acquires first current data, second current data, and physical state parameters of the target power distribution fiber; wherein, the first current data and second current data are obtained by modulating the terminals at different locations of the target power distribution fiber; the physical state parameters are obtained by solving the reverse Rayleigh scattering signal on the target power distribution fiber; the physical state parameters include several state data items. The state type determination module is used to determine the state type of the target power distribution optical fiber based on the first current data, the second current data, and the physical state parameters; wherein, the state type includes physical fault state and communication link abnormal state; The differential protection control module is used to generate a corresponding control command according to the state type when it is determined that the target power distribution fiber is in a physical fault state or a communication link abnormal state, and send the control command to the execution end to control the execution end to perform the corresponding differential protection action; wherein, the control command includes an open trip command or a blocked trip command.

9. A terminal device, characterized in that, include: The processor, memory, communication interface, and communication bus are provided, wherein the processor, memory, and communication interface communicate with each other via the communication bus. The memory is used to store at least one executable instruction that causes the processor to perform the operation of the differential protection method based on power distribution fiber as described in any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium includes a stored computer program, wherein, when the computer program is executed, it controls the device or apparatus containing the computer-readable storage medium to perform the differential protection method based on power distribution optical fiber as described in any one of claims 1 to 7.

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