Intelligent Management and Control Method and System for Power Line Differential Protection Channels Based on OLP

Abstract

This invention relates to the field of electrical communication transmission technology, specifically disclosing an intelligent management and control method and system for power differential protection channels based on OLP. The method includes: collecting optical layer and environmental parameters of the primary optical fiber within a sliding time window, calculating a health degradation index, and triggering backup screening if the index continuously exceeds the warning baseline or shows a monotonically increasing trend; periodically injecting optical probe test frames into the backup optical fiber to construct a transmission quality score vector, comparing it with the admission benchmark vector to screen switchable backup optical fibers; further employing grey relational analysis to determine the target switching fiber and generate a switching signal; responding to the switching signal, synchronously freezing the differential calculation engine and expanding the cache before execution of the switch, adjusting the sampling synchronization alignment window according to the time delay difference between the primary and backup optical fibers after the switch, and restarting the differential calculation after synchronization is restored. This invention achieves proactive fault prediction, quantitative selection of backup channels, and coordinated smooth switching of protection devices.

Description

Technical Field

[0001] This invention relates to the field of electrical communication transmission technology, specifically to an intelligent management and control method and system for power differential protection channels based on OLP. Background Technology

[0002] Longitudinal current differential protection is the primary protection method for high-voltage and ultra-high-voltage transmission lines. Its core principle relies on the real-time exchange of sampled data and differential current calculations between the protection devices at both ends of the line via a dedicated optical fiber channel. Therefore, the transmission quality of the optical fiber communication channel directly affects the reliability, speed, and selectivity of the differential protection. To ensure high availability of the protection channel, engineering projects typically employ a dual-route optical fiber redundancy scheme based on Optical Line Protection (OLP) devices. This involves configuring a primary optical fiber and a backup optical fiber. When the primary optical fiber fails, the OLP device automatically switches the optical path to the backup optical fiber to maintain the continuity of the protection channel.

[0003] Numerous studies and improvements have been made to fiber optic line protection technology based on OLP (Optical Line Protection). For example, Chinese invention patent CN115589253B discloses a fiber optic line protection method and system based on OLP. This method uses a signal monitoring device to monitor the main link fiber optic line to obtain a main signal monitoring dataset, then performs power prediction to obtain the fault probability. When the fault probability exceeds a preset threshold, a switching command is obtained, and a backup link is connected for signal testing to generate backup line indicators. When the backup line indicators meet the requirements, the switching is executed. This scheme introduces fault probability prediction and backup link testing before switching, which improves the reliability of switching to a certain extent.

[0004] However, the aforementioned existing technologies still have the following shortcomings: First, fault prediction methods suffer from lag and limitations. Existing technologies primarily rely on optical power as a single dimension for fault prediction. However, the degradation of power optical cables often manifests first as latent characteristics such as increased polarization mode dispersion and decreased optical signal-to-noise ratio, rather than a significant drop in optical power. Predicting based solely on power is highly susceptible to missing the "sub-healthy" state of the optical fiber, resulting in the channel performance failing to meet the sub-millisecond synchronization requirements of longitudinal differential protection at the moment of a grid fault, leading to protection failure or maloperation. Furthermore, the prediction model relies on historical statistical characteristics, limiting its ability to perceive the slow degradation trend of the optical fiber and missing the optimal opportunity for early assessment and preparation of backup channels.

[0005] Second, the quality assessment of backup channels suffers from the "instantaneous sampling" defect and lacks a quantitative selection mechanism. Current technology only performs a one-time signal test on the backup link before the switching decision, rather than continuously and actively monitoring the transmission performance of the backup fiber in idle state. This "single test before switching" approach has the following inherent defects: First, there is a time difference between the test and the switching time, during which the channel quality may change due to environmental changes or fiber disturbances, resulting in the backup fiber's performance no longer meeting the longitudinal differential protection requirements when the actual switching occurs; second, current technology only provides a binary conclusion of "meets the criteria" or "does not meet the criteria," without establishing a multi-dimensional quantitative scoring system for transmission quality. When multiple backup fibers exist, it is impossible to conduct a refined comparison and ranking of their transmission quality, making it difficult to select the best-performing backup fiber from multiple candidate backup fibers for switching.

[0006] Third, there is a lack of a coordinated switching mechanism with the differential protection device. Current technology, when performing optical path switching, only focuses on the physical operation of the optical switch itself, without considering the impact of the switching process on the differential calculation engine of the protection devices at both ends. When the optical path switches from the primary fiber to the backup fiber, due to the different transmission delays of the two fibers, the sampled value sequence received by the protection device will experience a phase abrupt change. If differential current calculation is performed directly, a false differential current several times the rated current will be generated, which can easily lead to false tripping of the protection device and seriously threaten the safe and stable operation of the power grid. Summary of the Invention

[0007] In view of this, in order to solve the problems mentioned in the background technology, a method and system for intelligent control of power differential protection channels based on OLP is proposed.

[0008] The technical solution adopted by this invention to solve its technical problem is: In a first aspect, the present invention provides an intelligent management and control method for power differential protection channels based on OLP, comprising the following steps: S1. Collect the optical layer parameters and environmental parameters of the primary optical fiber within the sliding time window, and calculate the health degradation index accordingly. If the health degradation index continues to exceed the warning baseline or shows a monotonically increasing trend, it is determined that the primary optical fiber has a tendency to fail and the backup optical fiber screening process is triggered.

[0009] S2. Periodically inject optical probe test frames into the backup optical fiber to obtain bit error rate, packet loss rate, jitter value and round-trip delay to construct a transmission quality score vector, and compare it with the admission benchmark vector of the longitudinal differential protection channel dimension by dimension to screen the switchable backup optical fiber.

[0010] S3. Using grey relational analysis, calculate the correlation between each switchable backup fiber and the ideal reference vector, determine the switchable backup fiber with the highest correlation as the switching target fiber, and generate a switching trigger signal.

[0011] S4. In response to the switching trigger signal, before the switching is performed, the differential calculation engine is frozen synchronously and the depth of the sampled value receiving buffer is expanded. After the switching is completed, the sampled value synchronization alignment window is adjusted according to the transmission delay difference between the primary fiber and the switching target fiber. After the synchronization is restored, the differential calculation is restarted.

[0012] Secondly, the present invention also provides an intelligent management and control system for power differential protection channels based on OLP, including: The risk prediction module collects the optical layer parameters and environmental parameters of the primary optical fiber within a sliding time window, and calculates the health degradation index accordingly. If the health degradation index continues to exceed the warning baseline or shows a monotonically increasing trend, it is determined that the primary optical fiber has a tendency to fail, and the backup optical fiber screening process is triggered.

[0013] The backup screening module periodically injects optical probe test frames into the backup optical fiber to obtain bit error rate, packet loss rate, jitter value and round-trip delay to construct a transmission quality score vector. It then compares this vector with the admission benchmark vector of the longitudinal differential protection channel dimension by dimension to screen switchable backup optical fibers.

[0014] The target selection module uses grey relational analysis to calculate the correlation between each switchable backup fiber and the ideal reference vector, determines the switchable backup fiber with the highest correlation as the switching target fiber, and generates a switching trigger signal.

[0015] The collaborative switching module, in response to the switching trigger signal, synchronously freezes the differential calculation engine and expands the depth of the sampled value receiving buffer before the switching is performed. After the switching is completed, it adjusts the sampled value synchronization alignment window according to the transmission delay difference between the primary fiber and the switching target fiber. After synchronization is restored, the differential calculation is restarted.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention collects optical layer parameters and environmental parameters of the primary optical fiber within a sliding time window, calculates the health degradation index using linear weighted fusion and environmental compensation, and proactively determines the fault risk tendency of the primary optical fiber based on the dual trend criteria of "continuously exceeding the warning baseline" and "overall monotonically increasing". This achieves a leap from passive switching to proactive prediction, and can identify the latent degradation trend of the primary optical fiber from seconds to hundreds of milliseconds before the primary optical fiber is completely interrupted and trigger the screening of backup optical fibers in advance. This avoids protection malfunctions and failures to operate due to sudden bit errors or performance degradation, and improves the anticipation and accuracy of fault response.

[0017] 2. This invention periodically injects optical probe test frames into backup optical fibers to continuously and actively acquire bit error rate, packet loss rate, jitter value, and round-trip delay, and constructs a transmission quality scoring vector. It then sequentially compares and selects switchable backup optical fibers dimension by dimension through the admission benchmark vector, and uses grey relational analysis to calculate the correlation between each switchable backup optical fiber and the ideal reference vector to determine the target switching fiber. This achieves continuous monitoring and quantitative optimization of the transmission quality of backup optical fibers, eliminating the risk of performance changes between the "single test before switching" and the switching time, and enabling the selection of the best-performing backup optical fiber from multiple backup optical fibers for switching.

[0018] 3. This invention generates a switching warning flag in response to a switching trigger signal and sends it to the peer device before the optical switch performs a physical switching. This synchronously freezes the differential calculation engines at both ends and expands the depth of the sampled value receiving buffer. After the switching is completed, the sampled values ​​are shifted to synchronize the window based on the transmission delay difference between the primary fiber and the target fiber. After synchronization is restored, the differential calculation is restarted. This achieves a smooth and coordinated switching with the longitudinal differential protection device. During the switching process, the differential calculation does not generate false differential current, and the protection device does not malfunction or refuse to operate. This achieves a "zero-impact" switching effect on the protection device and ensures the safe and stable operation of the power grid. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the method flow of the present invention.

[0021] Figure 2 This is a system module connection diagram of the present invention. Detailed Implementation

[0022] To further illustrate the technical means and effects adopted by the present invention to achieve its intended purpose, the following, in conjunction with the accompanying drawings and preferred embodiments, details the specific implementation, structure, features, and effects of the intelligent control method and system for power differential protection channels based on OLP proposed by the present invention. In the following description, different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics in one or more embodiments can be combined in any suitable form.

[0023] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0024] The specific scheme of the intelligent management and control method and system for power differential protection channels based on OLP provided by the present invention will be described in detail below with reference to the accompanying drawings.

[0025] This invention collects optical layer and environmental parameters of the primary optical fiber within a sliding time window, calculates a health degradation index, and triggers backup screening if the index continuously exceeds the warning baseline or shows a monotonically increasing trend. It periodically injects optical probe test frames into the backup optical fiber to construct a transmission quality score vector, which is compared with the admission benchmark vector to screen for switchable backup optical fibers. Furthermore, it uses grey relational analysis to determine the target fiber for switching and generates a switching signal. In response to the switching signal, the differential calculation engine is frozen and the buffer is expanded before switching. After switching, the sampling synchronization alignment window is adjusted based on the time delay difference between the primary and backup optical fibers, and differential calculation is restarted after synchronization is restored. This invention achieves proactive fault prediction, quantitative selection of backup channels, and coordinated smooth switching of protection devices.

[0026] Please see Figure 1 As shown, the first aspect of the present invention provides an intelligent management and control method for power differential protection channels based on OLP, comprising the following steps S1-S4.

[0027] Step S1: Collect the optical layer parameters and environmental parameters of the primary optical fiber within the sliding time window, and calculate the health degradation index accordingly. If the health degradation index continues to exceed the warning baseline or shows a monotonically increasing trend, it is determined that the primary optical fiber has a tendency to fail, and the backup optical fiber screening process is triggered.

[0028] In a preferred embodiment of the present invention, the method for acquiring the optical layer parameters and environmental parameters of the primary optical fiber within the sliding time window in step S1 includes: Set the length of the sliding time window and the sampling frequency within the time window.

[0029] By deploying an optical performance monitoring module on the primary fiber link, the received optical power, optical signal-to-noise ratio, and polarization mode dispersion of the primary fiber are collected at each sampling time point within each time window to construct an optical layer parameter set.

[0030] Furthermore, by deploying environmental sensors, the temperature, humidity, and external stress of the optical cable junction box of the main optical fiber are collected synchronously at each sampling time point to construct an environmental parameter set.

[0031] The optical layer parameter set and the environmental parameter set collected at each sampling time point within the time window are timestamped to generate the optical layer parameter time series and the environmental parameter time series.

[0032] Data cleaning is performed on the optical layer parameter timing and environmental parameter timing within the time window to obtain the timing data stream of the optical layer parameters and environmental parameters of the primary fiber within the time window.

[0033] The data cleaning process is as follows: For any parameter time series, calculate the average value and standard deviation of the time series, and determine the numerical fluctuation band of the parameter accordingly. Identify the data points in the time series that jump out of the numerical fluctuation band and record them as abnormal data points. Use the mean of the two data points adjacent to the abnormal data point as the correction value of the abnormal data point.

[0034] It should be noted that the number of sliding time windows, the length of a single time window, and the sampling frequency within the window are set based on the real-time requirements of the longitudinal differential protection and the physical response characteristics of the optical layer parameters. As an example, the number of sliding time windows is set to three to form a robust trend judgment basis and avoid false triggering; the length of a single time window is set to 200 milliseconds, aligned with the power frequency cycle, balancing the capture of slow time-varying characteristics and the reflection of fault accumulation effects; the sampling frequency within the window is set to 1000 Hz to meet the sampling requirements for the time-domain fluctuation details and polarization state changes of the optical layer parameters. The sampling frequencies of environmental parameters and optical layer parameters can differ to reduce data acquisition and processing overhead. For example, for a 50-kilometer 220 kV line, three consecutive time windows of 200 milliseconds each, overlapping by 50 milliseconds, are deployed. The optical layer parameters are sampled at 1000 Hz, and the environmental parameters at 50 Hz, generating corresponding time sequences.

[0035] It should be noted that, for any parameter time series, the numerical fluctuation band is determined as follows: calculate the average value of the parameter time series. with standard deviation And based on the 3σ criterion, the numerical fluctuation band is set as follows: .

[0036] In a preferred embodiment of the present invention, the method for calculating the health decline index in step S1 includes: Extract the safe operating limits corresponding to the optical layer parameters and environmental parameters of the optical fiber pre-stored in the database.

[0037] Based on the timing sequence of optical layer parameters within the time window, the average received optical power, average optical signal-to-noise ratio, and average polarization mode dispersion are calculated. These three values ​​are then compared with their respective safe operating limits to obtain the relative reduction in received optical power, the relative reduction in optical signal-to-noise ratio, and the relative increase in polarization mode dispersion.

[0038] The ratio of the relative reduction in received optical power to its safe operating limit is calculated to obtain the received optical power reduction ratio.

[0039] Similarly, the ratio of the relative reduction in optical signal-to-noise ratio to its safe operating limit is calculated to obtain the optical signal-to-noise ratio reduction ratio.

[0040] The polarization mode dispersion rise ratio is obtained by calculating the ratio of the relative increment of polarization mode dispersion to its safe operating limit.

[0041] Based on the decrease ratio of received optical power, the decrease ratio of optical signal-to-noise ratio, and the increase ratio of polarization mode dispersion, and combined with the preset confidence weights of received optical power, optical signal-to-noise ratio, and polarization mode dispersion in assessing health decline, a preliminary estimate of the health decline index is calculated through linear weighted fusion analysis.

[0042] The compensation amount for the health decline index is calculated based on the time series of environmental parameters within the time window. The initial estimate of the health decline index is added to the compensation amount to calculate the health decline index for the time window.

[0043] It should be noted that the safe operating limits for optical layer parameters are set based on the physical boundaries of the fiber optic link transmission performance and the engineering requirements for signal quality from the longitudinal differential protection channel. Specifically, these include the lower threshold for received optical power, the lower threshold for optical signal-to-noise ratio, and the upper threshold for polarization mode dispersion. The safe operating limits for environmental parameters are set based on the environmental tolerance level within the optical cable junction box and the temperature, humidity, and stress range for normal equipment operation. Specifically, these include the upper thresholds for temperature, humidity, and external stress. The above safe operating limits are obtained through the following methods: extracting nominal parameters from design documents during the planning and design phase of the power communication network; determining them based on recommended limits in ITU-T G.652 / G.655 and other fiber optic standards and GB / T 15972.1, the test method for the mechanical performance of optical cables; or using the statistical distribution of parameters from similar lines under historical normal operating conditions, taking the 99% confidence interval boundary as the safe operating limit. As a specific example: In a longitudinal differential protection channel of a 220 kV line using G.652D optical fiber with a transmission distance of 50 km, the pre-stored safe operation limits are as follows: the lower limit of safe operation of received optical power is -28 dBm (corresponding to the sensitivity of the optical receiver), the lower limit of safe operation of optical signal-to-noise ratio is 20 dB (using a 100 GHz filter and a resolution bandwidth of 0.1 nm), the upper limit of safe operation of polarization mode dispersion is 15 picoseconds (corresponding to a power cost of less than 1 dB at a rate of 40 Gbit / s); the upper limit of safe operation of temperature is 45℃, the upper limit of safe operation of humidity is 95% (non-condensing), and the upper limit of safe operation of external stress is 150 microstrain (corresponding to an additional attenuation of less than 0.1 dB in the optical cable).

[0044] It should be noted that the decrease in received optical power directly indicates an increase in transmission loss in the optical fiber link; the decrease in optical signal-to-noise ratio (SNR) reflects a degradation in the ratio of signal power to noise power; and the increase in polarization mode dispersion (PMD) means an increase in the time delay difference between different polarization states of light waves in the fiber, leading to pulse broadening and intersymbol interference. The degradation of these three optical layer parameters is interrelated and has synergistic characterization characteristics: a decrease in received optical power exacerbates the degradation of the SNR, while an increase in PMD further reduces the system's tolerance to signal distortion. Therefore, by fusing the three indicators—received optical power decrease ratio, optical SNR decrease ratio, and PMD increase ratio—and combining their respective confidence weights in health assessment, a weighted fusion can be performed to comprehensively quantify the transmission health status of the optical fiber from three dimensions: energy attenuation, SNR degradation, and signal distortion, enabling early prediction of fault risk tendencies.

[0045] It should be noted that the confidence weights of received optical power, optical signal-to-noise ratio (SNR), and polarization mode dispersion (PMD) in assessing health degradation are set as follows: Received optical power is a fundamental indicator of the energy transmission integrity of an optical fiber link. Its decline directly triggers power budget alarms and has the most direct impact on the availability of longitudinal differential protection channels, therefore it is given the highest confidence weight. Optical SNR reflects the degree of signal quality contamination by noise. In medium- and long-distance transmission, degradation occurs before received optical power, providing early warning value, and it is given the second highest confidence weight. PMD mainly affects the transmission quality of high-speed signals and is more sensitive in systems with speeds of 40 Gbit / s and above, but its impact is relatively limited in conventional 2.5 Gbit / s or 10 Gbit / s longitudinal differential protection channels, therefore it is given a lower confidence weight. As a specific example: for a 10 Gbit / s 220 kV line longitudinal differential protection channel, the confidence weight of received optical power is set to 0.5, the confidence weight of optical SNR is 0.3, and the confidence weight of PMD is 0.2, with a sum of 1 for all three. Furthermore, the confidence weights can be adaptively adjusted. For example, when the transmission distance exceeds 80 kilometers, the natural attenuation of the optical signal-to-noise ratio intensifies, so its weight is increased to 0.4, while the weight of the received optical power is decreased to 0.4; when the line rate increases to 40 Gbit / s or higher, the impact of polarization mode dispersion on signal distortion is significantly enhanced, so its weight is increased to 0.35, while the weights of the received optical power and optical signal-to-noise ratio are correspondingly reduced.

[0046] In a preferred embodiment of the present invention, the method for calculating the compensation amount of the health decline index includes: The environmental parameters within the time window are normalized. The normalization process involves comparing the environmental parameters collected within the time window with their corresponding safe operating limits.

[0047] Based on the normalized environmental parameter time series, the coefficients of variation of temperature time series, humidity time series and external stress time series are calculated, and the dimensionless maximum increase of temperature, humidity and external stress are calculated respectively.

[0048] Based on the preset influence weights of temperature, humidity, and external stress, the time series variation coefficients of temperature, humidity, and external stress are weighted and summed to obtain the first environmental stress factor.

[0049] Meanwhile, the second environmental stress factor is obtained by weighted summation of the dimensionless maximum increases in temperature, humidity and external stress.

[0050] The environmental stress value is obtained by summing the first environmental stress factor and the second environmental stress factor.

[0051] Based on the preset quantitative mapping relationship between environmental stress value and compensation amount of health decline index, the compensation amount of health decline index corresponding to the environmental stress value is determined.

[0052] It should be noted that, considering the driving effect of environmental factors on optical fiber transmission performance, changes in optical layer parameters are usually induced by environmental factors. Therefore, the health degradation index is compensated and corrected based on the temperature, humidity, and external stress of the optical cable junction box. Specifically, an increase in the temperature of the optical cable junction box can lead to thermal expansion of the optical fiber and changes in its refractive index distribution; humidity penetration can accelerate contamination or oxidation of the connector end face; and the application of external stress may cause microbending of the optical fiber or loosening of the connector. Thus, the degradation of optical layer parameters is a result of environmental stress acting on the physical medium of the optical fiber. If the health degradation index is calculated solely based on optical layer parameters, although it can reflect the current state of transmission performance degradation, it is difficult to distinguish the reversibility and evolution trend of degradation. Based on this, on the initial estimate of the health degradation index obtained by weighted fusion of optical layer parameters, an environmental stress compensation amount based on temperature, humidity, and external stress is further introduced to construct a dual closed-loop evaluation mechanism between environmental load input and optical layer performance response. This allows for both identification of existing performance degradation and prediction of fault risk tendencies driven by continuous environmental effects, thereby improving the accuracy and predictive ability of the assessment of fault risk in the primary optical fiber.

[0053] It should be noted that the coefficients of variation for temperature time series, humidity time series, and external stress time series are calculated using the following method: calculate the standard deviation and mean of the time series, and then use the ratio of the standard deviation to the mean as the coefficient of variation for the time series.

[0054] It should be noted that the dimensionless maximum increase of temperature, humidity, and external stress is calculated using the following method: For any environmental parameter, based on the time series of the environmental parameter, the increase corresponding to each sampling time point is calculated, and the maximum value in the calculation results is determined as the dimensionless maximum increase of the environmental parameter; wherein, the calculation method for the increase corresponding to any sampling time point is: calculate the relative increment of the parameter value at the sampling time point relative to the parameter value at the previous sampling time point, then calculate the ratio of the relative increment to the parameter value at the previous sampling time point, and use this ratio as the dimensionless increase value at the sampling time point. It should be further noted that when the parameter value at the previous sampling time point is zero, the dimensionless increase value at the sampling time point is set to zero or a preset upper limit value.

[0055] It should be noted that the weights of temperature, humidity, and external stress are set based on the damage mechanism, duration, and cumulative effect of each environmental parameter on optical fiber transmission performance. Specifically, temperature changes can cause alterations in refractive index distribution, and its effect is widespread and persistent, thus it is assigned the highest weight. Humidity mainly causes contamination, oxidation, or corrosion of connector end faces through penetration; its effect is cumulative and irreversible, but it usually manifests gradually during medium- to long-term operation, with a slower effect than temperature, thus it is assigned a medium weight. External stress includes residual stress after optical fiber laying and mechanical disturbances during operation; its effect is sudden and spatially uneven, and it occurs less frequently in normal operating environments, thus it is assigned the lowest weight. As a specific example: for the longitudinal differential protection channel of an overhead 220 kV line, the weight of temperature is set to 0.5, the weight of humidity to 0.3, and the weight of external stress to 0.2, with a sum of 1.

[0056] It should be noted that the quantitative mapping relationship between environmental stress values ​​and the compensation amount of the health degradation index is obtained as follows: Based on historical operating data or offline experimental data, the actual degradation degree of the photosphere parameters under different environmental stress conditions is collected, and the functional relationship between the two is established by curve fitting, piecewise linear interpolation, or table lookup. Specifically, the environmental stress value is normalized to the [0,1] interval, and the compensation amount of the health degradation index is mapped to the [0,0.3] interval to limit the correction range of the compensation amount relative to the initial estimate and avoid over-compensation leading to misjudgment. As a specific example for reference: For a 220 kV line longitudinal differential protection channel, 100 consecutive days of historical operating data are collected, and the daily environmental stress value and the corresponding actual degradation increment of the photosphere parameters are calculated. After data fitting, the following piecewise linear mapping relationship is obtained: The compensation amount is 0 when the environmental stress value is 0; 0.02 when the environmental stress value is 0.2; 0.05 when the environmental stress value is 0.4; 0.09 when the environmental stress value is 0.6; 0.15 when the environmental stress value is 0.8; and 0.30 when the environmental stress value is 1.0.

[0057] For environmental stress values ​​that do not directly correspond to discrete points, linear interpolation is used to calculate the compensation amount. Assuming the current environmental stress value is 0.55, which falls between the compensation amount of 0.05 corresponding to 0.4 and the compensation amount of 0.09 corresponding to 0.6, the compensation amount is calculated using the linear interpolation formula: 0.05 + (0.55 - 0.4) / (0.6 - 0.4) × (0.09 - 0.05) = 0.08. This mapping relationship can be periodically updated based on the accumulation of actual operating data to continuously optimize the compensation accuracy.

[0058] It should be noted that the coefficient of variation characterizes the relative fluctuation of each environmental parameter within a time window. Its magnitude reflects the severity and instability of environmental stress changes. A larger coefficient of variation indicates more severe fluctuations in environmental parameters, stronger alternating loads on the optical fiber medium, and a higher risk of material fatigue and performance degradation. The dimensionless maximum increase characterizes the maximum relative rate of increase of each environmental parameter between adjacent sampling points. Its magnitude reflects the intensity and impact of abrupt changes in environmental stress. A larger increase indicates that environmental parameters change drastically in a short period of time, making it difficult for the optical fiber and connector to respond promptly through thermal equilibrium or mechanical adaptation, easily leading to sudden performance degradation. By weighted fusion of the first and second environmental stress factors, a comprehensive environmental stress value is obtained. This quantifies both the cumulative damage risk caused by the severity of environmental parameter fluctuations and the immediate failure risk triggered by the rate of change in environmental parameters, thus comprehensively characterizing the impact of environmental stress on the health status of optical fibers from both the fluctuation amplitude domain and the change rate domain.

[0059] In a preferred embodiment of the present invention, the method for determining whether the primary optical fiber has a tendency to fail in step S1 includes: Summarize the health decline index calculated for each time window, and plot the curve of the health decline index changing over time.

[0060] Based on historical normal operation data of the primary optical fiber, a warning baseline for the health decline index is determined.

[0061] If the health decline index calculated for N consecutive time windows exceeds the warning baseline, and the value of N is greater than the preset quantity threshold, then the health decline index is determined to have continuously exceeded the warning baseline.

[0062] A linear fit is performed on the curve of the health decline index over time. If the slope of the fitted regression line is positive and the correlation coefficient of the linear fit is greater than the preset correlation coefficient threshold, then the health decline index is determined to show a monotonically increasing trend.

[0063] When the health decline index continues to exceed the warning baseline or shows a monotonically increasing trend, it is determined that the primary optical fiber has a tendency to fail; otherwise, it is determined that the primary optical fiber has no tendency to fail.

[0064] It should be noted that the method for determining the early warning baseline of the health degradation index based on the historical normal operation data of the primary optical fiber is as follows: Several health degradation indices were continuously calculated during the historical normal operation period of the primary optical fiber (i.e., periods with no fault risk and normal channel operation), forming a historical health degradation index sequence; the moving average and standard deviation of this sequence were calculated, and the early warning baseline was set as the moving average plus k times the standard deviation, where k ranges from 2.0 to 3.0. As a specific example for reference: the health degradation index of the primary optical fiber was collected for 500 consecutive time windows (each time window is 200 milliseconds long) under normal operation, and the overall mean of the historical health degradation index was calculated to be 0.12, with a standard deviation of 0.03; selecting k=2.5, then the early warning baseline is: 0.12 + 2.5 × 0.03 = 0.195. If the health degradation index for three consecutive time windows is 0.21, 0.23, and 0.22 respectively, all exceeding the warning baseline of 0.195, and the value of 3 is greater than the preset threshold of 2, then the health degradation index is determined to have continuously exceeded the warning baseline, triggering one of the conditions for determining fault risk tendency. The aforementioned warning baseline can be updated periodically based on the accumulation of historical operational data. For example, the mean and standard deviation are recalculated after every 1000 newly added normal operating time windows of health degradation index to adapt to the time-varying characteristics of the current optical fiber.

[0065] It should be noted that the correlation coefficient threshold for linear fitting is set based on the fluctuation characteristics of the time-series data of the health decline index and the reliability requirements for fault trend identification. The correlation coefficient measures the degree of linear correlation between the curve of the health decline index over time and the fitted regression line. The closer its absolute value is to 1, the stronger the monotonic linear trend of the health decline index over time. Considering that the process of fiber optic health decline is usually gradual and cumulative, its health decline index should show a continuous and stable upward trend in the fault risk tendency stage, rather than random fluctuations or brief jumps. If the correlation coefficient threshold is set too low, random fluctuations or non-monotonic changes may be misjudged as a monotonic increasing trend, leading to an increased false alarm rate; if the correlation coefficient threshold is set too high, the actual slow but continuous monotonic increasing trend may be missed, reducing the sensitivity of the warning. In a specific embodiment, statistical analysis of a large amount of historical operating data shows that when the correlation coefficient threshold is set to 0.85, noise interference can be effectively suppressed while maintaining a high trend identification accuracy.

[0066] Step S2: Periodically inject optical probe test frames into the backup optical fiber to obtain bit error rate, packet loss rate, jitter value and round-trip delay to construct a transmission quality score vector, and compare it with the admission benchmark vector of the longitudinal differential protection channel dimension by dimension to screen the switchable backup optical fiber.

[0067] In a preferred embodiment of the present invention, the method for screening switchable backup optical fibers in step S2 includes: Optical probe test frames with the same rate and encoding format as the service signal are periodically injected into the spare optical fiber. The wavelength of the optical probe test frames is combined with the service wavelength and transmitted via wavelength division multiplexing.

[0068] The optical probe test frame is captured and parsed at the receiving end of the backup optical fiber. The original values ​​of bit error rate, packet loss rate, jitter value and round-trip delay are calculated. The original values ​​are mapped to dimensionless scores between 0 and 1 through a normalization function, where 1 represents the best quality. Thus, a transmission quality score vector is constructed.

[0069] The transmission quality score vector is compared with the admission reference vector of the longitudinal differential protection channel in each dimension. The backup optical fiber that meets the admission reference vector requirements in each dimension is selected and used as the switchable backup optical fiber.

[0070] It should be noted that, in one specific embodiment, the injection period of the optical probe test frame is 500ms. The optical probe test frame and the service signal have the same rate and encoding format, specifically: when the service signal is a 2Mbit / s E1 signal, the optical probe test frame adopts the same 2Mbit / s rate and HDB3 encoding format, the wavelength of the optical probe test frame is 1510nm, and the wavelength of the service signal is 1550nm.

[0071] It should be noted that the bit error rate (BER) is calculated as follows: the ratio of the number of erroneous bits per unit time to the total number of bits, and this ratio is taken as the BER. The average of multiple calculations is then used as the final BER. The packet loss rate is calculated as follows: the ratio of the number of lost probe frames to the total number of transmitted frames, and this ratio is used as the packet loss rate. The jitter value is calculated as follows: the variance of the arrival interval between adjacent probe frames is calculated, and this variance is used as the jitter value. The round-trip time (RTD) is calculated as follows: half the time difference between sending a request frame and receiving a response frame, half of this time difference is used as the RTD, and the average of multiple calculations is used as the final RTD.

[0072] It should be noted that the method for mapping the original values ​​of bit error rate, packet loss rate, jitter value, and round-trip delay to dimensionless scores between 0 and 1 using a normalization function is as follows: The upper tolerance limits for each transmission quality indicator of the longitudinal differential protection channel are pre-obtained, including the upper tolerance limits for bit error rate, packet loss rate, jitter value, and round-trip delay. In a specific embodiment, the upper tolerance limit for bit error rate is... The upper tolerance limits are 0.1% for packet loss rate, 50 microseconds for jitter, and 5 milliseconds for round-trip delay. For bit error rate, packet loss rate, jitter, and round-trip delay, smaller original values ​​indicate better transmission quality; therefore, a reduced half-gradient normalization function is used for mapping. Specifically, when the original value of a certain indicator is 0, the mapping score is 1; when the original value reaches or exceeds the corresponding tolerance limit, the mapping score is 0; when the original value is between 0 and the tolerance limit, a linear interpolation formula is used to calculate the mapping score: score = 1 - (original value / tolerance limit). Through the above normalization process, original measurements of different dimensions and orders of magnitude are uniformly mapped to a comparable range of 0 to 1, facilitating the subsequent construction of a transmission quality score vector and its dimension-by-dimensional comparison with the admission benchmark vector.

[0073] It should be noted that, as an example, the transmission quality score vector is represented as follows: ,in, These represent the bit error rate, packet loss rate, jitter value, and round-trip time after normalization, respectively.

[0074] It should be noted that the admission reference vector for the longitudinal differential protection channel is determined based on the tolerance limits for bit error rate, packet loss rate, jitter value, and round-trip delay. This vector is used to determine whether the backup fiber meets the channel performance requirements for the normal operation of the longitudinal differential protection device and to prohibit switching to backup fibers that do not meet the conditions. Specifically, the critical scores corresponding to the tolerance limits of each indicator after normalization function mapping are used as the basic threshold of the admission reference vector. As a concrete example, the normalized longitudinal differential protection channel admission reference vector is set as follows: Specifically, the transmission quality score vector of the backup optical fiber must reach 0.80 or higher in all dimensions to be considered a switchable backup optical fiber. It should also be noted that the admission benchmark vector is a dynamic admission benchmark vector, adaptively adjusting the thresholds of each dimension based on the real-time transmission quality of the primary optical fiber: when the transmission quality score of a certain dimension of the primary optical fiber decreases, the corresponding admission benchmark threshold is relaxed accordingly to increase the screening range of switchable backup optical fibers and avoid protection channel interruption due to primary fiber degradation without a qualified backup optical fiber to switch to; however, the transmission quality corresponding to the thresholds of each dimension of the relaxed admission benchmark vector must never be worse than the false tripping threshold of the differential protection device, meaning that after switching to the backup optical fiber, the channel transmission quality must still meet the minimum requirements for normal operation of the differential protection device to ensure the reliability of protection action. For example, when the bit error rate score of the primary fiber decreases, the bit error rate dimension threshold of the admission reference vector is reduced accordingly (i.e., a slightly higher bit error rate is allowed), but the bit error rate value corresponding to this threshold is never higher than (i.e., the quality is not inferior to) the bit error rate corresponding to the malfunction threshold set by the longitudinal differential protection device, thereby expanding the screening range of backup fibers while maintaining the safety bottom line of protection action.

[0075] It should be noted that if no backup fiber meets the requirements of the admission benchmark vector in all dimensions of the transmission quality score vector, channel switching will be prohibited and an alarm message indicating that no backup fiber is available will be reported.

[0076] Step S3: Using grey relational analysis, calculate the correlation degree between each switchable backup fiber and the ideal reference vector, determine the switchable backup fiber with the highest correlation degree as the switching target fiber, and generate a switching trigger signal.

[0077] In a preferred embodiment of the present invention, the method for determining the target optical fiber in step S3 includes: If there is only one switchable backup fiber, then that switchable backup fiber is designated as the target fiber for switching.

[0078] If there are multiple switchable backup optical fibers, the grey relational analysis method is used to calculate the correlation degree between each switchable backup optical fiber and the ideal reference vector. The switchable backup optical fiber with the highest correlation degree is determined as the target fiber for switching. Here, the ideal reference vector is (1,1,1,1), and the resolution coefficient in the grey relational analysis is... The value is 0.5.

[0079] In one specific implementation, the process of calculating the correlation degree between each switchable backup fiber and the ideal reference vector using grey relational analysis is as follows: First, a decision matrix is ​​established, with the transmission quality score vectors of each switchable backup fiber used as the comparison sequence and the ideal reference vector (1,1,1,1) used as the reference sequence.

[0080] Secondly, calculate the absolute difference between each comparison sequence and the reference sequence in each dimension.

[0081] Next, calculate the grey relational coefficients for each dimension. The formula for calculation is as follows: .

[0082] In the above formula, For the first The switchable backup fiber optic cable is in the... Grey relational coefficient in dimension For the reference sequence in the 1st Dimension value, For the first The switchable backup fiber optic cable is in the... Dimension value, The resolution coefficient is set to 0.5.

[0083] Then, the average value of the grey correlation coefficient of each switchable backup fiber in each dimension is calculated, which gives the correlation degree between the backup fiber and the ideal reference vector.

[0084] Finally, the correlation between each backup fiber is compared, and the fiber with the highest correlation is selected as the target fiber for switching.

[0085] As a concrete example for reference, suppose there are two switchable backup optical fibers with transmission quality score vectors A=(0.85,0.90,0.80,0.95) and B=(0.95,0.85,0.75,0.90), and the ideal reference vector is (1,1,1,1).

[0086] Calculate the absolute difference: For backup fiber A, the absolute differences in each dimension are (0.15, 0.10, 0.20, 0.05); for backup fiber B, the absolute differences in each dimension are (0.05, 0.15, 0.25, 0.10). The global minimum absolute difference is 0.05, the global maximum absolute difference is 0.25, and the resolution coefficient is... ,but , .

[0087] Calculate the correlation coefficients for each dimension: For the backup fiber A, the dimension 1 coefficient = (0.05 + 0.5 × 0.25) / (0.15 + 0.5 × 0.25) = 0.175 / 0.275 ≈ 0.636.

[0088] Dimension 2 coefficient = 0.175 / (0.10+0.125) = 0.175 / 0.225 ≈ 0.778.

[0089] Dimension 3 coefficient = 0.175 / (0.20+0.125) = 0.175 / 0.325≈0.538.

[0090] Dimension 4 coefficient = 0.175 / (0.05+0.125) = 0.175 / 0.175 = 1.000.

[0091] Correlation degree = (0.636 + 0.778 + 0.538 + 1.000) / 4 ≈ 0.738.

[0092] For the backup fiber B, the dimension 1 coefficient = 0.175 / (0.05+0.125) = 0.175 / 0.175 = 1.000.

[0093] Dimension 2 coefficient = 0.175 / (0.15+0.125) = 0.175 / 0.275≈0.636.

[0094] Dimension 3 coefficient = 0.175 / (0.25+0.125) = 0.175 / 0.375≈0.467.

[0095] Dimension 4 coefficient = 0.175 / (0.10+0.125) = 0.175 / 0.225≈0.778.

[0096] Relevance = (1.000 + 0.636 + 0.467 + 0.778) / 4 ≈ 0.720.

[0097] Since 0.738 > 0.720, the correlation of backup fiber A is greater than that of backup fiber B, so backup fiber A is selected as the target fiber for switching.

[0098] Step S4: In response to the switching trigger signal, before the switching is performed, the differential calculation engine is frozen synchronously and the depth of the sampled value receiving buffer is expanded. After the switching is completed, the sampled value synchronization alignment window is adjusted according to the transmission delay difference between the primary fiber and the switching target fiber. After the synchronization is restored, the differential calculation is restarted.

[0099] In a preferred embodiment of the present invention, step S4 includes: In response to the handover trigger signal, a handover warning flag is generated before the optical switch performs a physical handover, and the handover warning flag is sent to the peer OLP device and the peer longitudinal differential protection device via in-band communication.

[0100] After the local differential protection device and the remote differential protection device confirm that they have received the switching warning flag, they simultaneously freeze the differential calculation engine and expand the depth of the sampled value receiving buffer.

[0101] After the OLP device completes the optical path switching, a switching completion flag is obtained. In response to the switching completion flag, the longitudinal difference protection devices at both ends are triggered to measure the transmission delay difference between the primary optical fiber and the switching target optical fiber.

[0102] The sampling value synchronization alignment window is adjusted according to the transmission delay difference, and the differential calculation is restarted after synchronization is restored.

[0103] It should be noted that, in one specific embodiment, the handover warning flag is sent via in-band communication through the idle overhead byte of the service channel. The handover warning flag includes frame type identifier and timestamp information. The transmission of the handover warning flag is completed before the physical handover action of the optical switch, and the warning lead time is 10ms to 25ms.

[0104] It should be noted that, in a specific embodiment, the specific method of synchronously freezing the differential calculation engine and expanding the sampling value receiving buffer depth is as follows: the differential protection devices at both ends complete the freezing of the output of the differential current calculation engine within 5ms after receiving the switching warning flag, and at the same time expand the sampling value receiving buffer depth from the default 4 sampling points to 40 sampling points. The expanded buffer depth corresponds to a 40ms switching impact tolerance time window.

[0105] It should be noted that if no confirmation response is received from the peer device within the preset timeout period (e.g., 25ms), it is determined that the peer device has not received the handover warning flag. At this time, the handover process is terminated and a channel status inconsistency alarm is reported.

[0106] In a preferred embodiment of the present invention, the method for adjusting the sampling value synchronization alignment window according to the transmission delay difference includes: Obtain the original sampling synchronization window, which is symmetrically distributed on both sides of the zero value with a radius of half the sampling interval.

[0107] Measure the transmission delay of the primary fiber and the transmission delay of the target fiber, and calculate the delay difference between the two.

[0108] The sampling synchronization alignment window is shifted by the time delay difference to obtain the adjusted sampling value synchronization alignment window.

[0109] It should be noted that, in one specific embodiment, the method for adjusting the sampling value synchronization alignment window based on the transmission delay difference is as follows: Assume the original sampling synchronization window is ,in The sampling interval is denoted as .

[0110] The transmission delay of the primary fiber optic cable was measured. Transmission delay with target fiber The difference Then, adjust the synchronization alignment window to... This is to eliminate the pseudo-differential current introduced by time delay jumps.

[0111] See Figure 2 As shown, the second aspect of the present invention provides an intelligent management and control system for power differential protection channels based on OLP, including a risk prediction module, a backup screening module, a target selection module, and a collaborative switching module.

[0112] The backup initial screening module is connected to the risk prediction module and the target selection module respectively, and the collaborative switching module is connected to the target selection module.

[0113] The risk prediction module is used to collect the optical layer parameters and environmental parameters of the primary optical fiber within a sliding time window, and calculate the health degradation index accordingly. If the health degradation index continues to exceed the warning baseline or shows a monotonically increasing trend, it is determined that the primary optical fiber has a tendency to fail and the backup optical fiber screening process is triggered.

[0114] The backup screening module is used to periodically inject optical probe test frames into the backup optical fiber to obtain bit error rate, packet loss rate, jitter value and round-trip delay, so as to construct a transmission quality score vector and compare it with the admission benchmark vector of the longitudinal differential protection channel dimension by dimension to screen the switchable backup optical fiber.

[0115] The target selection module is used to calculate the correlation between each switchable backup fiber and the ideal reference vector using the grey relational analysis method, determine the switchable backup fiber with the highest correlation as the switching target fiber, and generate a switching trigger signal.

[0116] The collaborative switching module is used to respond to the switching trigger signal. Before the switching is performed, it synchronously freezes the differential calculation engine and expands the depth of the sampled value receiving buffer. After the switching is completed, it adjusts the sampled value synchronization alignment window according to the transmission delay difference between the primary fiber and the switching target fiber. After the synchronization is restored, the differential calculation is restarted.

[0117] It should be noted that the order of the above embodiments of the present invention is merely for descriptive purposes and does not represent the superiority or inferiority of the embodiments. The processes depicted in the accompanying drawings do not necessarily require a specific or sequential order to achieve the desired result. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0118] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to interchangeably. The focus of each embodiment is on its differences from other embodiments. In particular, the apparatus embodiments are described simply because they are fundamentally based on the method embodiments; relevant details can be found in the descriptions of the method embodiments.

[0119] For ease of description, the above devices are described separately by function as various units. Of course, in implementing this application, the functions of each unit can be implemented in one or more software and / or hardware.

[0120] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0121] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0122] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0123] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0124] Secondly, the accompanying drawings of the embodiments disclosed in this invention only involve structures related to the embodiments disclosed in this invention. Other structures can refer to general designs. In the absence of conflict, the same embodiment and different embodiments of this invention can be combined with each other.

[0125] Finally, the above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for intelligent control of power differential protection channels based on OLP, characterized in that, Includes the following steps: S1. Collect the optical layer parameters and environmental parameters of the primary optical fiber within the sliding time window, and calculate the health degradation index accordingly. If the health degradation index continues to exceed the warning baseline or shows a monotonically increasing trend, it is determined that the primary optical fiber has a tendency to fail and the backup optical fiber screening process is triggered. S2. Periodically inject optical probe test frames into the backup optical fiber to obtain bit error rate, packet loss rate, jitter value and round-trip delay, so as to construct a transmission quality score vector and compare it with the admission benchmark vector of the longitudinal differential protection channel dimension by dimension to screen the switchable backup optical fiber. S3. Using the grey relational analysis method, calculate the correlation degree between each switchable backup fiber and the ideal reference vector, determine the switchable backup fiber with the highest correlation degree as the switching target fiber, and generate a switching trigger signal. S4. In response to the switching trigger signal, before the switching is performed, the differential calculation engine is frozen synchronously and the depth of the sampled value receiving buffer is expanded. After the switching is completed, the sampled value synchronization alignment window is adjusted according to the transmission delay difference between the primary fiber and the switching target fiber. After the synchronization is restored, the differential calculation is restarted.

2. The intelligent control method for power differential protection channels based on OLP according to claim 1, characterized in that, Methods for collecting optical layer parameters and environmental parameters of the primary optical fiber within a sliding time window include: Set the length of the sliding time window and the sampling frequency within the time window; By deploying an optical performance monitoring module on the primary fiber link, the received optical power, optical signal-to-noise ratio and polarization mode dispersion of the primary fiber are collected at each sampling time point within each time window to construct an optical layer parameter set. And by deploying environmental sensors, the temperature, humidity and external stress of the optical cable junction box of the main optical fiber are collected synchronously at each sampling time point to construct an environmental parameter set; The optical layer parameter set and the environmental parameter set collected at each sampling time point within the time window are timestamp aligned to generate the optical layer parameter time series and the environmental parameter time series. Data cleaning is performed on the optical layer parameter timing and environmental parameter timing within the time window to obtain the timing data stream of the optical layer parameter and environmental parameter of the main fiber within the time window; The data cleaning process is as follows: For any parameter time series, calculate the average value and standard deviation of the time series, and determine the numerical fluctuation band of the parameter accordingly. Identify the data points in the time series that jump out of the numerical fluctuation band and record them as abnormal data points. Use the mean of the two data points adjacent to the abnormal data point as the correction value of the abnormal data point.

3. The intelligent control method for power differential protection channels based on OLP according to claim 1, characterized in that, Methods for calculating the health decline index include: Extract the safe operating limits corresponding to the optical layer parameters and environmental parameters of the optical fiber pre-stored in the database; Based on the timing of the optical layer parameters within the time window, the average received optical power, average optical signal-to-noise ratio, and average polarization mode dispersion are calculated. The three are then compared with their respective safe operation limits to obtain the relative reduction in received optical power, the relative reduction in optical signal-to-noise ratio, and the relative increase in polarization mode dispersion. The ratio of the relative reduction in received optical power to its safe operating limit is calculated to obtain the received optical power reduction ratio; Similarly, by calculating the ratio of the relative reduction in optical signal-to-noise ratio to its safe operating limit, the optical signal-to-noise ratio reduction ratio can be obtained. The polarization mode dispersion rise ratio is obtained by calculating the ratio of the relative increment of polarization mode dispersion to its safe operating limit. Based on the decrease ratio of received optical power, the decrease ratio of optical signal-to-noise ratio, and the increase ratio of polarization mode dispersion, and combined with the preset confidence weights of received optical power, optical signal-to-noise ratio, and polarization mode dispersion in assessing health decline, a preliminary estimate of the health decline index is calculated through linear weighted fusion analysis. The compensation amount for the health decline index is calculated based on the time series of environmental parameters within the time window. The initial estimate of the health decline index is added to the compensation amount to calculate the health decline index for the time window.

4. The intelligent control method for power differential protection channels based on OLP according to claim 3, characterized in that, Methods for calculating the compensation amount for health decline index include: The environmental parameters within the time window are normalized. The normalization process involves comparing the environmental parameters collected within the time window with their corresponding safe operating limits. Based on the normalized environmental parameter time series, calculate the coefficients of variation for temperature time series, humidity time series and external stress time series respectively, and calculate the dimensionless maximum increase of temperature, humidity and external stress respectively. Based on the preset influence weights of temperature, humidity and external stress, the time series variation coefficients of temperature, humidity and external stress are weighted and summed to obtain the first environmental stress factor. Meanwhile, the second environmental stress factor is obtained by weighted summation of the dimensionless maximum increase of temperature, humidity and external stress. The environmental stress value is obtained by summing the first environmental stress factor and the second environmental stress factor. Based on the preset quantitative mapping relationship between environmental stress value and compensation amount of health decline index, the compensation amount of health decline index corresponding to the environmental stress value is determined.

5. The intelligent control method for power differential protection channels based on OLP according to claim 1, characterized in that, Methods for determining whether the primary fiber optic cable has a tendency to fail include: Summarize the health decline index calculated for each time window, and plot the curve of the health decline index changing over time. Based on the historical normal operation data of the primary optical fiber, a warning baseline for the health decline index is determined; If the health decline index calculated for N consecutive time windows exceeds the warning baseline, and the value of N is greater than the preset quantity threshold, then the health decline index is determined to have continuously exceeded the warning baseline. Linear fitting is performed on the curve of the health decline index over time. If the slope of the regression line obtained by the fitting is positive and the correlation coefficient of the linear fitting is greater than the preset correlation coefficient threshold, it is determined that the health decline index shows a monotonically increasing trend. When the health decline index continues to exceed the warning baseline or shows a monotonically increasing trend, it is determined that the primary optical fiber has a tendency to fail; otherwise, it is determined that the primary optical fiber has no tendency to fail.

6. The intelligent control method for power differential protection channels based on OLP according to claim 1, characterized in that, Methods for selecting switchable backup fiber optic cables include: Optical probe test frames with the same rate and encoding format as the service signal are periodically injected into the spare optical fiber. The wavelength of the optical probe test frame is combined with the service wavelength and transmitted by wavelength division multiplexing. The optical probe test frame is captured and parsed at the receiving end of the backup optical fiber. The original values ​​of bit error rate, packet loss rate, jitter value and round-trip delay are calculated. The original values ​​are mapped to dimensionless scores between 0 and 1 through a normalization function, where 1 represents the best quality. Thus, a transmission quality score vector is constructed. The transmission quality score vector is compared with the admission reference vector of the longitudinal differential protection channel in each dimension. The backup optical fiber that meets the admission reference vector requirements in each dimension is selected and used as the switchable backup optical fiber.

7. The intelligent control method for power differential protection channels based on OLP according to claim 1, characterized in that, Methods for determining the target fiber optic cable to switch to include: If there is only one switchable backup fiber, then that switchable backup fiber is designated as the target fiber for switching. If there are multiple switchable backup optical fibers, the grey relational analysis method is used to calculate the correlation degree between each switchable backup optical fiber and the ideal reference vector. The switchable backup optical fiber with the highest correlation degree is determined as the target fiber for switching. Here, the ideal reference vector is (1,1,1,1), and the resolution coefficient in the grey relational analysis is... The value is 0.

5.

8. The intelligent control method for power differential protection channels based on OLP according to claim 1, characterized in that, Step S4 includes: In response to the switching trigger signal, a switching warning flag is generated before the optical switch performs a physical switching, and the switching warning flag is sent to the peer OLP device and the peer longitudinal differential protection device via in-band communication. After the local differential protection device and the remote differential protection device confirm that they have received the handover warning flag, they simultaneously freeze the differential calculation engine and expand the sampling value receiving buffer depth. After the OLP device completes the optical path switching, a switching completion flag is obtained. In response to the switching completion flag, the longitudinal difference protection devices at both ends are triggered to measure the transmission delay difference between the primary optical fiber and the switching target optical fiber. The sampling value synchronization alignment window is adjusted according to the transmission delay difference, and the differential calculation is restarted after synchronization is restored.

9. The intelligent control method for power differential protection channels based on OLP according to claim 8, characterized in that, Methods for adjusting the sampling value synchronization alignment window based on the transmission delay difference include: Obtain the original sampling synchronization window, which is symmetrically distributed on both sides of the zero value with half the sampling interval as the radius; Measure the transmission delay of the primary fiber and the transmission delay of the target fiber to be switched, and calculate the delay difference between the two. The sampling synchronization alignment window is shifted by the time delay difference to obtain the adjusted sampling value synchronization alignment window.

10. An intelligent control system for power differential protection channels based on OLP, characterized in that, include: The risk prediction module collects the optical layer parameters and environmental parameters of the primary optical fiber within a sliding time window, and calculates the health decline index accordingly. If the health decline index continues to exceed the warning baseline or shows a monotonically increasing trend, it is determined that the primary optical fiber has a tendency to fail and the backup optical fiber screening process is triggered. The backup screening module periodically injects optical probe test frames into the backup optical fiber to obtain bit error rate, packet loss rate, jitter value and round-trip delay, so as to construct a transmission quality score vector and compare it with the admission benchmark vector of the longitudinal differential protection channel dimension by dimension to screen the switchable backup optical fiber. The target selection module uses grey relational analysis to calculate the correlation between each switchable backup fiber and the ideal reference vector, determines the switchable backup fiber with the highest correlation as the switching target fiber, and generates a switching trigger signal. The collaborative switching module, in response to the switching trigger signal, synchronously freezes the differential calculation engine and expands the depth of the sampled value receiving buffer before the switching is performed. After the switching is completed, it adjusts the sampled value synchronization alignment window according to the transmission delay difference between the primary fiber and the switching target fiber. After synchronization is restored, the differential calculation is restarted.

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