A primary and secondary fusion complete set of circuit breaker edge self-calibration method and device

Abstract

The application relates to the technical field of power distribution automation equipment, and discloses a method and device for edge self-calibration of primary-secondary fusion integrated set pole-mounted circuit breaker. The method collects primary sensor measurement, secondary terminal phasor, zero sequence quantity, switch state, event record and transient waveform data of the pole-mounted circuit breaker, and after time unification, quality marking and calibration window screening, constructs power grid flow constraint, zero sequence balance constraint and switch transient event constraint respectively; based on the constraints, the amplitude correction coefficient, the phase correction coefficient, the time tag correction quantity and the time tag drift rate of each measurement channel are jointly estimated, and the reliability is generated according to the data quality, the constraint residual, the event effectiveness and the historical stability; when the reliability meets the condition, the correction coefficient is written and the corrected measurement data is output, otherwise the candidate coefficient is saved or the alarm is output, so that the primary-secondary fusion measurement link self-calibration under the condition of no power outage is realized.

Description

Technical Field

[0001] This invention relates to the field of online calibration technology for power distribution automation equipment, and in particular to an edge self-calibration method and apparatus for the measurement link of a primary and secondary integrated pole-mounted circuit breaker. Background Technology

[0002] Integrated pole-mounted circuit breakers typically integrate the primary switch body, current sensor, voltage sensor, zero-sequence sensor, secondary measurement and control terminal, protection control unit, and communication unit. They are widely used for distribution line segmentation, interconnection, fault isolation, and feeder automation control. These devices are installed in outdoor line environments and are subject to long-term effects from temperature and humidity changes, mechanical vibration, insulation aging, sensor magnetic circuit changes, secondary sampling link drift, and communication timing status changes. This can gradually lead to amplitude, phase, and timing deviations between the primary sensor output and the secondary terminal record. These deviations affect voltage and current measurements, zero-sequence detection, fault recording, event sequence recording, and the distribution master station's analysis of the line's operating status.

[0003] Existing calibration methods typically rely on factory calibration, periodic maintenance verification, portable standard source injection, standard transformer comparison, or test platform testing. While these methods can obtain relatively accurate calibration results under specific verification conditions, they require additional calibration equipment, on-site wiring, and manual operation. In some scenarios, power outages, bypassing, or changes in equipment operation modes are also necessary, making continuous calibration of pole-mounted circuit breakers in operation difficult. For distributed power distribution line equipment, relying solely on periodic manual verification can lead to persistent sensor drift or terminal clock drift between adjacent maintenance periods, resulting in long-term deviations in operational and fault event data.

[0004] Existing distribution terminals can detect some timescale anomalies or measurement anomalies through time synchronization signals, historical load curves, fault recordings, or operating status curves. However, this type of processing usually targets a single type of deviation and cannot simultaneously distinguish between amplitude error, phase error, and timescale drift. For power frequency phasors, timescale offset will manifest as phase angle offset; for zero-sequence quantities, phase channel proportional error, polarity error, and zero-sequence channel error may also present similar abnormal results. Without cross-verification between multiple operating constraints, relying solely on a single curve or threshold for judgment can easily lead to misinterpreting load surges, topology switching, grounding disturbances, or transient events as measurement link drift, and may also misjudge actual measurement deviations as ordinary operational fluctuations.

[0005] Furthermore, distribution network power flow constraints, zero-sequence balance relationships, and switch transient events are primarily used in existing distribution automation systems for power flow analysis, ground fault detection, fault location, or protection action analysis. They have not yet been effectively integrated into a self-calibration mechanism for the edge side of pole-mounted circuit breakers that integrate primary and secondary circuits. Especially under uninterrupted power supply conditions, how to utilize the steady-state measurements, zero-sequence measurements, and switch transient events collected by the equipment itself to jointly estimate the amplitude correction coefficient, phase correction coefficient, time scale correction, and time scale drift rate between primary sensors and secondary terminals, and how to avoid automatically writing correction parameters when reliability is insufficient, remain technical problems that need to be solved. Summary of the Invention

[0006] To address the challenge of simultaneously identifying primary sensor amplitude errors, phase errors, and secondary terminal timescale drift in integrated primary and secondary pole-mounted circuit breakers during operation, this invention provides a self-calibration method and apparatus for the edge of such bridging systems. This method utilizes three-phase voltage, three-phase current, zero-sequence voltage, zero-sequence current, switch status, secondary terminal event records, and transient waveform data collected by the pole-mounted circuit breaker itself. It establishes distribution network power flow constraints, zero-sequence balance constraints, and switch transient event constraints at the edge side. Based on the mutual verification relationships between these constraints, it jointly estimates the amplitude correction coefficient, phase correction coefficient, initial timescale correction, and timescale drift rate of the measurement channels. This results in an applicable, traceable, and rollback-capable calibration result without power outages or external standard sources.

[0007] One aspect of the present invention provides a method for edge self-calibration of a primary and secondary integrated pole-mounted circuit breaker. The method includes the following processing steps: S1, collecting three-phase voltage, three-phase current, zero-sequence voltage, zero-sequence current, switch status, secondary terminal event records, and transient waveform data during the operation of the pole-mounted circuit breaker, and performing unified time buffering and quality marking on the collected data; S2, based on switch status, topology status, load fluctuation, zero-sequence abnormal status, and time synchronization status, filtering steady-state calibration windows, zero-sequence balance windows, and switch transient event windows from the data; S3, constructing distribution network power flow constraint residuals based on the steady-state calibration windows, and constructing three-phase quantities based on the zero-sequence balance windows. The zero-sequence balance residual between the zero-sequence quantity and the event time difference residual between the primary waveform characteristic moment and the secondary terminal event time scale is constructed based on the switch transient event window; S4, the distribution network power flow constraint residual, zero-sequence balance residual and event time difference residual are input into the joint estimation model to obtain the amplitude correction coefficient, phase correction coefficient, initial time scale correction amount and time scale drift rate of the measurement channel; S5, the calibration confidence level is generated according to the data quality, constraint residual, event validity and historical stability, and the correction coefficient is written, the candidate coefficient is saved or the calibration alarm is output according to the calibration confidence level.

[0008] In S1, the three-phase voltage, three-phase current, zero-sequence voltage, and zero-sequence current can be phasor data output by the secondary terminal, or they can include short-window transient waveform data saved when an event is triggered. The switch state can include open state, close state, energy storage state, switch auxiliary contact state, remote control command state, and protection action state. The secondary terminal event record can include protection start time stamp, trip time stamp, close time stamp, reclosing time stamp, switch position change time stamp, time synchronization state change record, and communication anomaly record. By uniformly caching the above data, this invention can incorporate data from different sources, with different sampling frequencies, and with different time accuracies into the same calibration time axis, providing a consistent data foundation for subsequent constraint modeling.

[0009] Specifically, when uniformly buffering and marking the collected data, phasor data, zero-sequence data, switch state data, event log data, and transient waveform data with different sampling frequencies can be mapped to the same time axis according to the unified control time of the secondary terminal. For each data point, its sampling frequency, clock source, time synchronization status, communication status, range status, and waveform integrity are recorded. When data exhibits time jump, continuous fixedness, range out-of-bounds, sampling loss, communication interruption, or sensor saturation, an anomaly level is set for the corresponding data. When the anomaly level exceeds the preset usable level, the corresponding data is removed from the automatic calibration calculation; when the anomaly level does not exceed the preset usable level, the corresponding data is retained, and its weight in subsequent constraint calculations is reduced. This processing method avoids low-quality data from directly participating in calibration parameter estimation while retaining some data that still has reference value, thereby improving the calibration process's adaptability to fluctuations in field data.

[0010] In S2, the steady-state calibration window is used to construct distribution network power flow constraints, the zero-sequence balance window is used to construct consistency constraints between three-phase and zero-sequence quantities, and the switch transient event window is used to construct time constraints between primary waveform characteristics and secondary terminal event timescales. These three types of windows correspond to observable conditions for different error types. The steady-state calibration window is more sensitive to amplitude and phase deviations; the zero-sequence balance window is more sensitive to three-phase channel proportional deviations, polarity deviations, phase connection deviations, and zero-sequence channel proportional deviations; and the switch transient event window is more sensitive to initial timescale offsets and timescale drift. By filtering different windows at the edge, the impact of fault processes, topology changes, severe load fluctuations, and time synchronization anomalies on the calibration results can be reduced.

[0011] Specifically, when selecting the steady-state calibration window, the load change rate, power factor change rate, and phasor effectiveness score can be calculated within a time interval where the switch opening / closing status remains unchanged, the feeder topology remains unchanged, protection actions do not occur, the frequency deviation is within the allowable range, and there are no sudden changes in three-phase voltage and three-phase current. When the load change rate, power factor change rate, and phasor effectiveness score meet the steady-state window conditions, this time interval is used as the steady-state calibration window. When there are remote control operations, fault trips, reclosing, single-phase grounding disturbances, transformer saturation, or master station time synchronization anomalies, this time interval is excluded from the steady-state calibration window or its weight is reduced. When selecting the zero-sequence balance window, it can be determined whether the zero-sequence current, zero-sequence voltage, three-phase current imbalance, and three-phase voltage imbalance are within the explainable range of normal operation, and periods with obvious single-phase grounding, single-phase open circuits, arc suppression coil switching, and zero-sequence sensor saturation are excluded. When filtering the transient event window of a switch, the start and end range of the event can be determined based on SOE records, remote control commands, protection action information, switch auxiliary contact changes, and waveform change characteristics, and waveform data that can cover the transient changes before and after the event can be retained.

[0012] In S3, when constructing the distribution network power flow constraint residuals based on the steady-state calibration window, the branch power balance residuals, node current balance residuals, and voltage drop residuals can be calculated based on the line impedance, phase connection relationship, switch topology status, and phasor data of the feeder where the pole-mounted circuit breaker is located. The branch power balance residuals characterize the deviation between the corrected active and reactive power and the power calculated from voltage, current, and phase angle. The node current balance residuals characterize the deviation between the current entering and leaving the node. The voltage drop residuals characterize the deviation between the branch head voltage, branch current, line impedance, and branch end voltage. When upstream or downstream measurement data is missing, historical load curves or measurements from adjacent terminals can be used to form weak constraints, and the residual weight corresponding to these weak constraints can be reduced. Through this approach, this invention does not require each distribution node to be equipped with a high-precision synchronous measurement device, and can adapt to situations where on-site measurement conditions for distribution lines are incomplete.

[0013] When constructing zero-sequence balance residuals based on the zero-sequence balance window, balance relationships between three-phase quantities and zero-sequence quantities can be established for both the current and voltage channels. For the current channel, the deviation between the edge-side comparison-corrected sum of three-phase current phasors and the zero-sequence current quantity converted according to the zero-sequence output definition is considered. For the voltage channel, the deviation between the edge-side comparison-corrected sum of three-phase voltage phasors and the zero-sequence voltage quantity converted according to the zero-sequence output definition is considered. The three-phase current phasors, three-phase voltage phasors, zero-sequence current, and zero-sequence voltage all originate from the same zero-sequence balance window, and the configuration coefficients used for zero-sequence conversion correspond to the output definitions of the zero-sequence sensors or secondary terminals. When the zero-sequence quantity is a residual current or residual voltage output, the configuration coefficients are set to values ​​matching the residual current or residual voltage definition; when the zero-sequence quantity is a symmetrical component output, the configuration coefficients are set to values ​​matching the symmetrical component definition. Through the zero-sequence balance residuals, constraints can be applied to the three-phase channel proportional error, polarity error, phase connection error, and zero-sequence channel proportional error.

[0014] When constructing event time difference residuals based on the transient event window of a switch, the timing of current surges, voltage drops, peak transient energy envelopes, or arrival of oscillation characteristics can be extracted from transient waveform data when events such as opening, closing, fault tripping, or reclosing occur. Furthermore, protection start-up timestamps, switch position timestamps, and event sequence record timestamps can be read from the secondary terminal event records. Further, cross-correlation calculations can be performed on the primary waveform characteristic sequence and the secondary terminal event sequence to obtain the time delay corresponding to the correlated peak. When multiple sampling points exist near the correlated peak, interpolation can be used to determine the sub-sampling level time delay. The difference between this time delay and the current channel timestamp correction is used as the event time difference residual, and its weight is determined based on the event amplitude, signal-to-noise ratio, and event record integrity. Through this processing method, naturally occurring transient changes during switch operation are used as time calibration references, eliminating the need for additional calibration signals.

[0015] In S4, the joint estimation model can use the amplitude correction coefficient, phase correction coefficient, initial timescale correction, and timescale drift rate of each measurement channel as a set of calibration parameters. For phasor data, the edge side adjusts the phasor magnitude according to the candidate amplitude correction coefficient, adjusts the phase angle according to the candidate phase correction coefficient, and adjusts the time position corresponding to the phasor according to the candidate timescale correction and timescale drift rate. For transient waveform data, the edge side can first perform time axis correction according to the candidate timescale correction, and then perform resampling, interpolation, or waveform feature extraction. The above processing can be implemented using conventional phasor amplitude correction, phase angle correction, and time axis translation methods in the art, without relying on a specific form of custom mathematical model.

[0016] The joint estimation model can use a weighted residual evaluation method to solve for calibration parameters. Specifically, the edge side obtains the distribution network power flow constraint residuals, zero-sequence balance residuals, event time difference residuals, and historical smoothing residuals, and assigns weights to each residual based on window quality, constraint confidence, event validity, and historical stability. The historical smoothing residuals are used to constrain the variation between the current estimation result and historical valid calibration results, avoiding abrupt changes in correction coefficients caused by short-term abnormal windows. The solution method can use weighted least squares, recursive least squares, robust estimation, or conventional methods from Kalman filtering. When a certain type of constraint is unavailable in the current time period, the weight of that type of constraint can be reduced or its participation in the estimation can be suspended; when there are significant conflicts between multiple types of constraints, the overall calibration confidence can be reduced and automatic writing of correction coefficients can be prevented.

[0017] In S5, when generating calibration confidence, the data quality component can be obtained based on data missing rate, range validity, sampling integrity, and time synchronization status; the constraint residual component can be obtained based on the normalized results of distribution network power flow constraint residuals and zero-sequence balance residuals; the event validity component can be obtained based on the number of switch transient events, event intensity, cross-correlation peak value, and event record integrity; and the historical stability component can be obtained based on the differences between correction coefficients obtained from multiple consecutive calibration windows. At the edge, these components can be fused into calibration confidence using weighted averaging, hierarchical judgment, or product fusion methods. The value range, weight, and threshold of each component can be calibrated according to the accuracy level of the field equipment, data sampling capability, and operation and maintenance requirements.

[0018] When the calibration confidence level C reaches the automatic application threshold, the amplitude correction coefficient, phase correction coefficient, initial timescale correction amount, and timescale drift rate are written into the effective coefficient area, and the version number, source window, event number, generation time, applicable channel, and validity period are recorded. When the calibration confidence level C reaches the candidate saving threshold but is lower than the automatic application threshold, the corresponding correction coefficient is saved to the candidate coefficient area and the observation period is extended until subsequent window verification is passed before being written into the effective coefficient area. When the calibration confidence level C is lower than the candidate saving threshold, a calibration alarm is output without writing the correction coefficient. After the correction coefficient is written, the distribution network power flow constraint residual, zero-sequence balance residual, and event time difference residual before and after correction can be compared. If the residual does not decrease after correction or abnormal protection and control data occurs, the previous version coefficient is restored and the rollback reason is recorded.

[0019] Another aspect of the present invention provides an edge self-calibration device for a primary and secondary integrated pole-mounted circuit breaker. This device includes a multi-source data acquisition module, a time buffer and quality marking module, a calibration window filtering module, a distribution network power flow constraint module, a zero-sequence balance constraint module, a switch transient event module, a joint estimation module, a reliability assessment module, and a coefficient management module. The multi-source data acquisition module is used to acquire three-phase voltage, three-phase current, zero-sequence voltage, zero-sequence current, switch status, secondary terminal event records, and transient waveform data during the operation of the pole-mounted circuit breaker. The time buffer and quality marking module is used to map the acquired data to a unified time axis and set quality marks. The calibration window filtering module is used to filter steady-state calibration windows, zero-sequence balance windows, and switch transient event windows. The distribution network power flow constraint module is used to construct distribution network power flow constraint residuals based on the steady-state calibration windows. The zero-sequence balance constraint module is used to construct zero-sequence balance residuals between three-phase quantities and zero-sequence quantities based on the zero-sequence balance windows. The switch transient event module is used to construct event time difference residuals between the primary waveform characteristic moments and the secondary terminal event timescales based on the switch transient event windows. The joint estimation module is used to estimate the amplitude correction coefficient, phase correction coefficient, initial timescale correction, and timescale drift rate of the measurement channel based on the distribution network power flow constraint residual, zero-sequence balance residual, and event time difference residual. The reliability evaluation module is used to generate calibration reliability. The coefficient management module is used to write correction coefficients, save candidate coefficients, or output calibration alarms based on the calibration reliability.

[0020] This invention also provides a primary and secondary integrated pole-mounted circuit breaker. The circuit breaker includes a primary switch body, three-phase current sensors, three-phase voltage sensors, a zero-sequence sensor, a switch status acquisition unit, a secondary measurement and control terminal, an edge computing unit, and a communication unit. The three-phase current sensors, three-phase voltage sensors, and zero-sequence sensor are connected to the primary switch body and are used to collect feeder operation measurement data. The switch status acquisition unit is used to collect open state, closed state, and switch change information. The secondary measurement and control terminal is used to generate phasor data, event records, and transient waveform data. The edge computing unit is equipped with the edge self-calibration device of the primary and secondary integrated pole-mounted circuit breaker and is used to output corrected measurement data, correction coefficients, calibration reliability, and calibration alarms. The communication unit is used to send the corrected measurement data, calibration reliability, coefficient version number, and calibration alarms to the distribution master station or operation and maintenance platform, and to receive calibration strategy configuration, threshold configuration, and coefficient rollback instructions from the distribution master station or operation and maintenance platform.

[0021] In summary, the technical solution of this application performs unified time caching and quality marking on the edge side of the integrated primary and secondary pole-mounted circuit breaker for three-phase measurements, zero-sequence measurements, switch status, event records, and transient waveforms in operation, and selects steady-state calibration windows, zero-sequence balance windows, and switch transient event windows from them; furthermore, residual terms are formed by distribution network power flow constraints, zero-sequence balance constraints, and switch transient event constraints, and amplitude correction, phase correction, initial time scale correction, and time scale drift rate are incorporated into the same estimation model; finally, a credibility is generated based on data quality, constraint residuals, event validity, and historical stability, and the correction coefficients are processed according to the credibility by writing the effective value, saving the candidate, alarming, or rolling back, thereby forming an online self-calibration closed loop for the pole-mounted circuit breaker measurement link.

[0022] Compared with existing technologies, this invention can complete the measurement link calibration using the equipment's own operating data without power interruption, without external standard source, and without changing the primary wiring of the pole-mounted circuit breaker. Existing factory calibration or on-site maintenance calibration can usually only be performed under specific operating conditions, making it difficult to detect sensor drift or terminal timescale drift that gradually develops between two maintenance operations. This invention, by continuously filtering the operating window and event window, allows calibration calculations to accumulate data during normal equipment operation and can automatically apply calibration results based on reliability.

[0023] Secondly, for power frequency phasors, time scale offset may manifest as phase angle offset; for zero-sequence quantities, three-phase channel errors and zero-sequence channel errors may also influence each other. If separate amplitude verification, phase verification, or time scale detection methods are used, it is easy to cause inaccurate error attribution. This invention integrates distribution network power flow constraints, zero-sequence balance constraints, and event time difference constraints into a unified joint estimation model, which is beneficial for distinguishing different error sources and outputting corresponding correction parameters in the same estimation process.

[0024] Furthermore, this invention employs a unified time cache, quality marking, and calibration window filtering to prevent obviously abnormal data from directly entering automatic calibration calculations. Through constraint weights and reliability mechanisms, when data quality is insufficient, constraints are inconsistent, or event validity is inadequate, the system will not directly write correction coefficients but will instead save candidate coefficients or output alarms. This approach helps avoid undue impacts of online self-calibration on protection and control operations.

[0025] Finally, this invention records the version number, source window, event number, generation time, applicable channel, and validity period when the correction coefficient is written, allowing for subsequent rollback based on residual changes and business status. Through this mechanism, operation and maintenance personnel can understand the basis for the calibration results and their reliability status. Edge devices can also automatically switch to candidate, alarm, or rollback paths when reliability is insufficient or the corrected effect does not meet requirements, thus providing traceable calibration information to the distribution master station or operation and maintenance platform. Attached Figure Description

[0026] To more clearly illustrate the technical solution of this application, the accompanying drawings are briefly described below.

[0027] Figure 1 This is a schematic diagram of the overall process of the self-calibration method for the edge of a primary and secondary integrated pole-mounted circuit breaker according to the present invention.

[0028] Figure 2 This is a schematic diagram of the system structure of the primary and secondary integrated pole-mounted circuit breaker edge self-calibration device of the present invention.

[0029] Figure 3 This is a schematic diagram illustrating the processing of multi-source data time alignment and quality marking in this invention.

[0030] Figure 4 This is a schematic diagram illustrating the principle of constructing power flow constraint residuals in the distribution network in this invention.

[0031] Figure 5 This is a schematic diagram illustrating the principle of constructing zero-order equilibrium constraints in this invention.

[0032] Figure 6 This is a schematic diagram of the time-stamp calibration process for switch transient events in this invention.

[0033] Figure 7 This is a schematic diagram illustrating the application and deployment of the integrated primary and secondary pole-mounted circuit breaker of the present invention in a power distribution line.

[0034] Figure 8 This is a multi-dimensional schematic diagram illustrating the technical effects of the edge self-calibration method of the present invention. Detailed Implementation

[0035] The embodiments of the present invention will be described below with reference to the accompanying drawings. The described embodiments are for illustrating the technical solutions of the present invention and are not intended to limit the present invention to implementation with exactly the same equipment configuration, data frequency, parameter thresholds, or calculation model. Without changing the processing relationship of edge self-calibration through distribution network power flow constraints, zero-sequence balance relationships, and switch transient events, those skilled in the art can make adaptive adjustments based on the distribution line voltage level, pole-mounted circuit breaker model, secondary terminal sampling capability, and on-site operation and maintenance requirements.

[0036] Example 1 This embodiment describes the overall process of the edge self-calibration method for primary and secondary integrated pole-mounted circuit breakers. (Refer to...) Figure 1This method is executed by a self-calibration program deployed in a secondary measurement and control terminal or edge computing unit. It mainly includes multi-source data acquisition and quality labeling, calibration window filtering, construction of multi-class constraint residuals, joint estimation, and confidence-driven coefficient output processing. This process runs in parallel with the normal protection and measurement and control operations of the pole-mounted circuit breaker, and does not change the protection tripping settings and protection action logic when the automatic application conditions are not met.

[0037] In step S1, the edge side collects three-phase voltage, three-phase current, zero-sequence voltage, zero-sequence current, switch status, secondary terminal event records, and transient waveform data during the operation of the pole-mounted circuit breaker. The three-phase voltage and current can originate from the power frequency phasors formed by primary sensors via a secondary sampling link, or from short-time waveforms formed by event-triggered waveform recording. The zero-sequence voltage and current can originate from zero-sequence sensors or equivalent zero-sequence quantities calculated from the three-phase quantities. The switch status can include open status, closed status, energy storage status, remote control command status, auxiliary contact change status, and protection action status. The secondary terminal event records can include protection start time stamps, trip time stamps, closing time stamps, reclosing time stamps, SOE recording time stamps, time synchronization anomaly records, and communication anomaly records. The transient waveform data can be voltage and current waveforms within a certain time range before and after the opening / closing or fault event.

[0038] Reference Figure 3 In step S1, the aforementioned data is further subjected to unified time buffering and quality marking. For transient waveform data with high sampling frequency, periodically output phasor data, discretely changing switch state data, and SOE records formed by event triggering, the edge side maps them to the same time axis according to the unified control time. The unified control time can be provided by the local clock of the secondary terminal, the time synchronization module, or the internal time base of the edge computing unit. When the secondary terminal is in a valid time synchronization state, the unified time axis uses the absolute time scale after time synchronization; when the time synchronization state is abnormal but the local clock continuity meets the requirements, the unified time axis can use the local continuous time scale, and the abnormal time synchronization state is recorded in the quality marking.

[0039] When performing quality labeling, the edge side records the sampling frequency, clock source, time synchronization status, communication status, range status, waveform integrity, and source channel for each type of data. If a channel exhibits range out-of-bounds, continuous fixed values, missing samples, communication interruption, time rollback, or waveform saturation, an anomaly level is assigned to that channel. Anomaly levels are categorized into three types: usable, downweighted, and excluded. Data in the usable state participates in subsequent calculations with normal weights; data in the downweighted state can still be used for some constraint calculations, but its weight is lower than normal data; data in the excluded state does not participate in automatic calibration parameter estimation and is only used as a basis for alarms or manual verification. Through this processing method, the edge side can avoid directly using obviously abnormal sensor data for solving correction coefficients.

[0040] In step S2, the edge side filters the steady-state calibration window, zero-sequence balance window, and switch transient event window from the unified time buffer. The steady-state calibration window is used to construct distribution network power flow constraints and should meet conditions such as no change in switch status, no change in line topology, no protection action, frequency deviation within the allowable range, and no significant abrupt changes in three-phase voltage and three-phase current. The edge side can calculate the load change rate, power factor change rate, phasor validity score, and data integrity score within the candidate time interval. When the above indicators meet the preset conditions, the time interval is determined as the steady-state calibration window. If remote control operation, fault tripping, reclosing, single-phase grounding disturbance, transformer saturation, or master station time synchronization anomaly occurs within the candidate time interval, the time interval is excluded, or its weight is reduced if the data still has some reference value.

[0041] The zero-sequence balance window is used to establish the balance relationship between three-phase quantities and zero-sequence quantities. When filtering this type of window, the edge side determines whether the zero-sequence current, zero-sequence voltage, three-phase current imbalance, and three-phase voltage imbalance are within the explainable range of normal operation. If there is a significant single-phase grounding, single-phase open circuit, arc suppression coil switching, zero-sequence transformer saturation, or zero-sequence sensor communication abnormality, this interval will not be used as the zero-sequence balance window for automatic calibration. For zero-sequence quantity changes caused by slight unbalanced loads, this window can be retained and robust residual processing can be used to prevent normal operating imbalances from being simply misjudged as sensor abnormalities.

[0042] The switch transient event window is used to construct time constraints. The edge side identifies opening, closing, fault tripping, and reclosing events based on SOE records, remote control commands, protection action information, auxiliary contact change information, and waveform abrupt change characteristics. For each event, the edge side extracts waveform segments covering the transient changes before and after the event and establishes a correspondence between the primary waveform characteristic time and the secondary terminal event timestamp. This event window does not require additional calibration signals from the field; instead, it utilizes naturally occurring waveform abrupt changes during switch operation as a time reference.

[0043] In step S3, the distribution network power flow constraint residuals, zero-sequence balance residuals, and event time difference residuals are constructed on the edge side, respectively. (Refer to...) Figure 4Distribution network power flow constraint residuals can be constructed based on the line impedance, phase connection relationship, switch topology status, and phasor data of the feeder where the pole-mounted circuit breaker is located. For lines with upstream and downstream measurements, branch power balance residuals, node current balance residuals, and voltage drop residuals can be calculated. Branch power balance residuals characterize the deviation between the corrected active and reactive power and the power calculated from voltage, current, and phase angle; node current balance residuals characterize the deviation between the current entering and leaving the node; and voltage drop residuals characterize the deviation between the branch head voltage, branch current, line impedance, and branch end voltage. If downstream measurements are lacking on-site, weak constraints can be formed using historical load curves, adjacent terminal measurements, or estimates from the distribution master station, with the corresponding weight of these weak constraints reduced.

[0044] Reference Figure 5 Zero-sequence balance residuals can be constructed separately for the current and voltage channels. For the current channel, the edge side compares the deviation between the corrected sum of three-phase current phasors and the zero-sequence current equivalent; for the voltage channel, the edge side compares the deviation between the corrected sum of three-phase voltage phasors and the zero-sequence voltage equivalent. The three-phase current phasors, three-phase voltage phasors, zero-sequence current, and zero-sequence voltage all originate from the same time window, and the zero-sequence equivalent is determined by the output definition of the zero-sequence sensor or secondary terminal. When the zero-sequence sensor output is residual current or residual voltage, the configuration coefficient is set according to the residual current or residual voltage definition; when the zero-sequence quantity is the zero-sequence component in a symmetrical component, the configuration coefficient is set according to the symmetrical component definition. Through this residual, the edge side can identify the three-phase channel proportional error, polarity error, phase connection error, and zero-sequence channel proportional error.

[0045] Reference Figure 6 The event time difference residual is constructed through the time relationship between the primary transient waveform and the secondary terminal event record. When a tripping, closing, fault tripping, or reclosing event occurs, the edge side extracts the current surge moment, voltage drop moment, transient energy envelope peak moment, or oscillation characteristic arrival moment from the transient waveform, and reads the protection start time stamp, switch change time stamp, and SOE record time stamp from the secondary terminal event record. The edge side performs cross-correlation calculations on the primary waveform characteristic sequence and the secondary terminal event sequence to obtain the time delay corresponding to the correlated peak. If multiple sampling points exist near the correlated peak, interpolation can be used to determine the subsampling level time delay. The difference between this time delay and the current channel time stamp correction is the event time difference residual. The weight of the event time difference residual can be determined based on the event amplitude, signal-to-noise ratio, and event record completeness.

[0046] In step S4, the edge side inputs the distribution network power flow constraint residual, zero-sequence balance residual, and event time difference residual into the joint estimation model to obtain the amplitude correction coefficient, phase correction coefficient, initial timescale correction, and timescale drift rate of the measurement channel. For the c-th measurement channel, the edge side can use the above four types of corrections as the same set of candidate calibration parameters and use them to adjust the amplitude, phase angle, and time position of the measurement value of that channel, respectively. For phasor data, the edge side adjusts the phasor magnitude according to the candidate amplitude correction coefficient, adjusts the phase angle according to the candidate phase correction coefficient, and adjusts the sampling time corresponding to the phasor according to the candidate timescale correction; for transient waveform data, the edge side performs translation or drift compensation on the time axis according to the candidate timescale correction. This processing belongs to the engineering correction of existing measurement data and does not require the construction of additional complex custom models.

[0047] The joint estimation model can employ a weighted residual evaluation method. At the edge, the distribution network power flow constraint residuals, zero-sequence balance residuals, event time difference residuals, and historical smoothing residuals are normalized respectively. Corresponding weights are then assigned based on window quality, constraint type, event validity, and historical stability. The solution objective is to reduce the overall residual and ensure stable changes in calibration parameters. The historical smoothing residual is used to constrain the variation between the current estimation result and historically valid calibration results. The solution method can employ weighted least squares, recursive least squares, robust estimation, or Kalman filtering. If a certain type of constraint is unavailable in the current period, its weight can be reduced or set to zero. If the estimation results of multiple types of constraints conflict, the estimation result is not directly adopted; instead, its confidence level is reduced, and further verification is awaited in subsequent windows.

[0048] In step S5, the edge side generates calibration confidence based on data quality, constraint residuals, event validity, and historical stability. Data quality can be obtained from data missing rate, range validity, sampling integrity, and time synchronization status; constraint residuals can be obtained from the normalized results of distribution network power flow constraint residuals and zero-sequence balance residuals; event validity can be obtained from the number of switch transient events, event intensity, cross-correlation peak value, and event record integrity; historical stability can be obtained from the differences between correction coefficients obtained from multiple consecutive calibration windows. The edge side can use weighted averaging, product fusion, or hierarchical rules to obtain calibration confidence based on the field operation and maintenance strategy. The value range and weight of each component can be configured according to the terminal sampling capability, field operation rules, and operation and maintenance strategy.

[0049] When the calibration confidence level reaches the automatic application threshold, the edge side writes the amplitude correction coefficient, phase correction coefficient, initial timescale correction, and timescale drift rate into the effective coefficient area, and records the version number, source window, event number, generation time, applicable channel, and validity period. When the calibration confidence level reaches the candidate saving threshold but is lower than the automatic application threshold, the edge side saves the corresponding correction coefficients to the candidate coefficient area and extends the observation window for further verification in subsequent steady-state windows, zero-sequence windows, or transient event windows. When the calibration confidence level is lower than the candidate saving threshold, the edge side outputs a calibration alarm without writing correction coefficients. After the correction coefficients are written, the edge side continues to compare the power flow residuals, zero-sequence residuals, and event time difference residuals before and after correction; if the residuals do not decrease after correction, or if the protection and control data are abnormal, the previous version of the coefficients is restored and the rollback reason is recorded.

[0050] This embodiment enables pole-mounted circuit breakers to perform edge self-calibration during normal operation using their own measurement data and naturally occurring switching transient events. This method does not require power outages, external standard sources, or changes to primary equipment wiring. Because the calibration results are reliability-controlled and have candidate saving and rollback paths, the impact of online calibration on protection and control operations can be reduced.

[0051] Example 2 This embodiment describes the specific implementation method of distribution network power flow constraints participating in amplitude correction and phase correction. (Refer to...) Figure 4 The pole-mounted circuit breaker is installed at a branch of the power distribution line. Figure 4 In the diagram, upstream node i represents the electrical node on the power supply side of the pole-mounted circuit breaker, and downstream node j represents the electrical node on the load side or downstream branch side of the pole-mounted circuit breaker. The line between node i and node j is represented by the line impedance Zij. Figure 4 The pole-mounted circuit breaker located in the middle corresponds to the edge self-calibration object of the present invention, whose three-phase voltage, three-phase current, active power, reactive power and switching status are formed by primary sensors and secondary measurement and control terminals. Figure 4 The connection relationship from upstream node i to pole-mounted circuit breaker and then from pole-mounted circuit breaker to downstream node j indicates that the power flow constraint residual in this embodiment is not generated in isolation based on a single measurement value, but rather based on the electrical relationship between node voltage, branch current, line impedance, and branch power.

[0052] Reference Figure 4The upper nodes i, pole-mounted circuit breaker, and node j, on the edge side, first read the feeder topology information and line parameter information corresponding to the current pole-mounted circuit breaker. The feeder topology information includes the upstream and downstream nodes, branch connection relationships, phase connection relationships, and current switch open / closed status of the pole-mounted circuit breaker; the line parameter information includes the line resistance, line reactance, line length, phase impedance parameters, and rated operating parameters between nodes i and j. If... Figure 4 If the pole-mounted circuit breaker is in the closed state and no topology switch has occurred in the power supply path between node i and node j, then the edge side allows this branch to enter the power flow constraint residual calculation. If the pole-mounted circuit breaker is in the open state, power supply switching state, protection action not reset state, or topology state uncertain state, then the edge side does not use the data of this period to construct the power flow constraint residual for automatic calibration, or only saves the data of this period as manual verification information.

[0053] Reference Figure 4 The values ​​Vi, Iij, Pij, Qij, and Vj marked in the figure represent the branch head voltage Vi, branch current Iij, branch active power Pij, branch reactive power Qij, and branch end voltage Vj acquired by the edge side within the steady-state calibration window. Vi can be formed from the supply side voltage collected by the pole-mounted circuit breaker voltage sensor, Iij can be formed from the branch current collected by the pole-mounted circuit breaker current sensor, and Pij and Qij can be calculated by the secondary measurement and control terminal based on voltage and current phasors, or supplemented by power measurements provided by the distribution master station or adjacent terminals. Vj is provided by the downstream terminal when downstream measurement is available on site; when downstream synchronous measurement is not available on site, it can be provided by historical load curves, transformer area operation data, or distribution master station state estimation results. All the above data have been subjected to the unified time buffer and quality marking described in Example 1 before entering the power flow constraint calculation, so that... Figure 4 Each electrical quantity corresponds to the same steady-state calibration window.

[0054] Reference Figure 4 The lower branch power balance residuals are used to calculate the branch power on the edge side based on the corrected voltage and current phasors, and compared with the power value recorded by the secondary terminal or distribution master station. For the c-th measurement channel, the corrected phasor is obtained from the original phasor through amplitude correction, phase angle correction, and time position correction. Taking branch ij as an example, the corrected branch power can be calculated based on the head-end voltage phasor and branch current phasor. If the active power and reactive power recorded by the terminal are Pij(t) and Qij(t) respectively, the active power deviation and reactive power deviation between the calculated power and the recorded power can be compared. When the current channel amplitude is too small or too large, the above deviations will show a consistent direction of change in multiple steady-state calibration windows; when there is a phase deviation in the voltage channel or current channel, the reactive power deviation and power factor related deviation will change accordingly. Therefore, Figure 4The branch power balance residuals can provide constraints for the amplitude correction coefficient and the phase correction coefficient.

[0055] Reference Figure 4 The residual current balance at the lower node can be constructed based on the current inflow and outflow of node i or node j if the location of the pole-mounted circuit breaker has multiple downstream branches or a comparable current relationship with adjacent terminals. For nodes with multiple branches, the difference between the corrected inflow and outflow current can be expressed as rI=ΣIin'(t)-ΣIout'(t). When only the branch current of the pole-mounted circuit breaker body can be obtained on-site, and synchronous measurement of all branches is not possible, Figure 4 The node current balance residuals can be downgraded to weak constraints. The data sources for weak constraints can be historical load curves, measurements from adjacent terminals, or state estimates of distribution substations. Weak constraints do not determine the correction coefficients independently, but are assigned a weight lower than that of direct measurement constraints in the joint estimation model, so as to provide a trend reference and avoid calibration result deviations caused by historical load estimation errors.

[0056] Reference Figure 4 The voltage drop residual at the bottom is used to estimate the voltage of node j on the edge side based on the head-end voltage Vi', branch current Iij', and line impedance Zij, and compared with the estimated value of Vj' or Vj. The voltage drop relationship can be expressed as Vj,cal'(t)=Vi'(t)-Zij·Iij'(t), and the voltage drop residual can be expressed as rV=Vj'(t)-Vj,cal'(t). If there is a deviation in the current path amplitude, the voltage drop amplitude obtained from Zij·Iij'(t) will deviate from the actual voltage drop; if there is a deviation in the current path phase, the directions of the active and reactive components of the voltage drop will deviate; if there is a phase deviation in the voltage path, the phase angle relationship between node voltages will also be inconsistent with the line impedance relationship. Therefore, Figure 4 The voltage drop residual shown can further supplement the branch power balance residual, and jointly constrain the amplitude and phase of the voltage path and the current path.

[0057] Reference Figure 4The three residual boxes are merged into the joint estimation model after residual normalization. The edge side does not directly input branch power deviation, node current deviation, and voltage drop deviation into the joint estimation model with their original dimensions; instead, they are first normalized. Branch power balance residuals can be normalized according to rated capacity or the average power within the steady-state window; node current balance residuals can be normalized according to rated current or the average current within the window; and voltage drop residuals can be normalized according to rated voltage or the normal voltage drop of the line. The normalized distribution network power flow constraint residuals participate in the solution as one type of residual in the joint estimation model, while other residual terms are provided by zero-sequence balance constraints and switching transient event constraints. This expression emphasizes the comprehensive evaluation relationship of multiple types of engineering residuals, avoiding limiting the specific solution process to a single complex formula.

[0058] In order to Figure 4 The power flow constraints shown only participate in calibration under suitable operating conditions, and the edge side also calculates a window availability score within each steady-state calibration window. This score can be determined by load change rate, frequency deviation, phasor validity, time synchronization, switch stability, and topology status. If the load changes rapidly within a window, although it can still be calculated... Figure 4 The branch power balance residuals and voltage drop residuals are included, but due to potential time misalignments between different measurements, the power flow constraint weight for this window should be reduced. If a single-phase grounding, reclosing, remote control operation, or protection activation occurs within a window, that window will not be included in the automatic power flow constraint estimation. In this way, Figure 4 The power flow constraint calculation in the example is connected to the window filtering step in Example 1.

[0059] In a specific scenario, the pole-mounted circuit breaker is located at the sectionalizing switch position of a 10kV distribution line, node i is the upstream feeder node, and node j is the downstream load node. The edge side reads Vi, Iij, Pij, Qij, and the line impedance Zij during multiple windows when the load is relatively stable at night, and then... Figure 4 The relationships shown are used to calculate the branch power balance residual and voltage drop residual, respectively. If multiple windows show that the active power calculated from the A-phase current is lower than the power recorded at the terminal, and the voltage drop residual also points to a low A-phase current amplitude, the joint estimation model will tend to increase the amplitude correction coefficient of the A-phase current path. If, at the same time, the zero-sequence balance residual does not show phase misconnection or polarity reversal, and the switching transient event residual does not show significant timescale drift, the reliability of the amplitude correction result will be correspondingly improved. Conversely, if the power flow constraints show that the A-phase current amplitude is low, but the zero-sequence balance residual indicates that there may be polarity or phase anomalies, the edge side will not rely solely on... Figure 4 Instead of writing the power flow constraints into the correction coefficients, the calibration confidence is reduced and the information to be reviewed is output.

[0060] In another specific scenario, node j is not configured with a directly readable synchronous voltage measurement. Figure 4 Vj in the equation is provided by the distribution master station's state estimation or historical load data. In this case, the voltage drop residual can still be constructed, but its weight is lower than when synchronous measurements are available. The edge side can prioritize using branch power balance residuals and node current balance residuals for estimation, and then use the voltage drop residual as an auxiliary constraint. If the subsequent distribution master station provides higher-reliability measurements of adjacent terminals, the edge side can increase the weight of the voltage drop residual. This approach allows... Figure 4 The power flow constraints shown can accommodate situations where field measurement configurations are incomplete, without requiring all line nodes to be equipped with synchronous high-precision terminals.

[0061] This embodiment can also be used to identify phase correction requirements. If the voltage and current amplitude residuals are small, but the reactive power residual, power factor residual, and voltage drop direction residual show consistent deviations across multiple steady-state windows, the edge side can determine that the measurement link may have a phase deviation or time scale offset. Since time scale offset also manifests as phase angle offset in power frequency phasors, the edge side does not directly attribute all of this deviation to phase correction, but rather combines... Figure 6 The time-scale calibration results of the switch transient events shown are distinguished. When Figure 6 When the corresponding event time difference residuals indicate a stable timescale offset in the secondary terminal, the joint estimation model will prioritize adjusting τc0 or βc; only when the event time difference residuals are small but the power flow residuals persist will the joint estimation model tend to adjust φc. Figure 4 and Figure 6 The combination of the constraints shown can reduce confusion between phase error and timescale error.

[0062] Through this embodiment, Figure 4 A complete processing link is formed between the upstream node i, pole-mounted circuit breaker, downstream node j, line impedance Zij, branch power balance residual, node current balance residual, voltage drop residual, and residual normalization input joint estimation model. This processing link can constrain the amplitude and phase consistency of primary sensors and secondary terminals using existing electrical relationships in the operation of the distribution line without external standard calibration sources. Since the power flow constraint residual is only one type of residual term in the joint estimation model and is controlled through window filtering, normalization, weight configuration, and credibility mechanisms, it can provide a usable but not overly rigid calibration basis for edge self-calibration even if the field measurements are incomplete or the load fluctuates.

[0063] Example 3 This embodiment describes the specific implementation method of calibration involving both zero-sequence balance constraints and switching transient event constraints. (Refer to...) Figure 5Zero-sequence balance constraints are used to describe the amplitude, phase, polarity, and wiring consistency relationships between the three-phase voltage and current paths and the zero-sequence voltage and current paths. (Refer to...) Figure 6 The switch transient event constraint is used to describe the time consistency relationship between the characteristic moment of the primary waveform and the time stamp of the secondary terminal event. Figure 5 and Figure 6 Supplementing from the perspectives of zero-order channel consistency and event timescale consistency Figure 4 The power flow constraints shown enable the present invention to simultaneously calibrate amplitude, phase, and timescale drift at the edge side.

[0064] Reference Figure 5 The upper A-phase, B-phase, C-phase, and zero-sequence channels first extract quality-marked data from a unified time buffer at the edge side. The A-phase channel corresponds to the corrected A-phase current phasor Ia' and A-phase voltage phasor Ua', the B-phase channel corresponds to the corrected B-phase current phasor Ib' and B-phase voltage phasor Ub', the C-phase channel corresponds to the corrected C-phase current phasor Ic' and C-phase voltage phasor Uc', and the zero-sequence channel corresponds to the corrected zero-sequence current I0' and zero-sequence voltage U0'. These phasors can be power frequency phasors output from the secondary terminal or electrical quantities obtained by phasor calculation from short-window waveforms. If a phase channel or zero-sequence channel has missing samples, out-of-range measurements, or saturation marks in the current window, that window will not enter automatic zero-sequence balancing calibration, or the weight of that channel will be reduced.

[0065] Reference Figure 5 The central part calculates the summation of three-phase quantities and the conversion of zero-sequence quantities. The edge side calculates the summation of three-phase currents Ia'+Ib'+Ic' and the converted zero-sequence current kI·I0', as well as the summation of three-phase voltages Ua'+Ub'+Uc' and the converted zero-sequence voltage kU·U0'. Here, kI and kU are configuration coefficients used to adapt to the output definitions of zero-sequence quantities from different zero-sequence sensors or secondary terminals. If the field zero-sequence sensor outputs residual current or residual voltage, kI or kU is set according to the residual current or residual voltage definition; if the secondary terminal outputs the zero-sequence component of a symmetrical component, kI or kU is set according to the proportional relationship between the symmetrical component and the three-phase summation. These configuration coefficients are determined by the equipment model, terminal parameters, or factory configuration file and can be distributed to the edge side by the operation and maintenance platform.

[0066] Reference Figure 5The balance residuals from the middle to the bottom are judged, and the zero-sequence current balance residuals and zero-sequence voltage balance residuals are constructed on the edge side. The zero-sequence current balance residual reflects the deviation between the corrected three-phase current phasor sum and the zero-sequence current conversion, and the zero-sequence voltage balance residual reflects the deviation between the corrected three-phase voltage phasor sum and the zero-sequence voltage conversion. During normal operation and in the absence of significant grounding anomalies, the above residuals should be within the allowable range of equipment accuracy, load imbalance, and line distribution parameters. If the zero-sequence balance residuals continuously deviate across multiple windows, and the direction of deviation is consistent with the change in the correction parameters of a certain phase channel or zero-sequence channel, then the edge side can use this deviation as calibration evidence for amplitude, phase, polarity, or wiring anomalies. If the residuals only occur during grounding disturbances, arc suppression coil operation, single-phase open circuits, or transient impacts, then these residuals are not used as the basis for automatic calibration.

[0067] Reference Figure 5 The three identification result boxes at the bottom can be used to classify and judge the residual shape based on the residual when the zero-sequence balance residual does not meet the threshold. If the three phase channels maintain a basically correct phase relationship, and there is a stable proportional difference between the zero-sequence channel output and the three-phase sum, it can be judged that there is a proportional error in the zero-sequence channel. If the residual direction changes with the load of a certain phase channel after it participates in the summation, it can be judged that the phase channel may have an amplitude proportional error or a phase deviation. If the residual decreases significantly after a certain phase channel is reversed or the phase is swapped, it can be judged that there may be a polarity reversal or a phase connection error. The above judgment results do not directly replace the joint estimation model, but are used to determine the structure, constraint direction, and confidence weight of the zero-sequence balance residual.

[0068] In a specific implementation, the edge side can calculate the mean square value, mean direction, phase angle distribution, and correlation with load variation of the zero-sequence current balance residual and the zero-sequence voltage balance residual for each zero-sequence balance window. If the mean square value of the zero-sequence current balance residual is higher than the threshold, but the zero-sequence voltage balance residual is normal, then the current path and the zero-sequence current path are checked first; if the zero-sequence voltage balance residual is abnormal but the zero-sequence current balance residual is normal, then the voltage path and the zero-sequence voltage path are checked first; if both are abnormal, then a combination of... Figure 4 Current constraints and Figure 6 The event timescale constraints are used to determine if there is a common timescale offset or a secondary sampling synchronization anomaly. Through this process, Figure 5 The zero-sequence balance constraint shown is not only used to detect the deviation of the zero-sequence channel itself, but also to help distinguish between the three-phase channel error and the time scale error.

[0069] Reference Figure 6(a) Transient waveform feature extraction: When the edge side detects a tripping, closing, fault tripping, or reclosing event, it extracts the characteristic moments from the transient waveforms of the primary side voltage and current. The characteristic moments can be the start of a current surge, the start of a voltage drop, the peak of the transient energy envelope, the zero-crossing surge, or the arrival of an oscillation characteristic. To reduce noise impact, the edge side can first perform bandpass filtering, sliding energy calculation, or differential rate of change calculation on the waveform, and then determine the characteristic moments at positions that meet the amplitude threshold and duration conditions. If the waveform exhibits saturation, missing components, or insufficient sampling rate, the event validity component of the event is reduced, and in severe cases, it may not participate in automatic time-scale calibration.

[0070] Reference Figure 6 (b) Secondary terminal event record alignment: The edge side reads the protection start time stamp, switch position time stamp, trip output time stamp, closing command time stamp, or reclosing action time stamp from the SOE record or protection action record, and matches these secondary event time stamps with the primary waveform characteristic moments. Since different terminals may have different triggering conditions for event records, the edge side can establish event matching rules for each type of event. For example, a fault trip event can match the start time of a current surge or voltage drop with the protection start time stamp, or the current disappearance time with the trip output time stamp; a closing event can match the rising edge of the inrush current with the closing position time stamp. The matching rules are determined by the device type and event definition configuration.

[0071] Reference Figure 6 The primary waveform characteristic time and SOE timescale are marked with dashed lines in the middle, and the edge side calculates the time difference between them. If both the primary waveform characteristic sequence and the secondary event sequence contain multiple feature points, the edge side can perform cross-correlation calculations, using the time delay corresponding to the correlation peak as the event time offset estimate. If the correlation peak is located between two sampling points, interpolation can be used to determine the subsampling level time delay. For the time offset estimates obtained from multiple events, the edge side assigns weights based on event intensity, signal-to-noise ratio, SOE integrity, and waveform sampling rate, and uses the weighted result as the initial timescale correction reference for the current time period.

[0072] Figure 6 The event time offset residuals marked in the figure represent the remaining deviation between the secondary terminal event timescale and the characteristic moment of the primary waveform. If this deviation remains similar across multiple events, it indicates the possible existence of a stable initial timescale offset τc0; if this deviation gradually increases or decreases over time, it indicates the possible existence of a timescale drift rate βc. On the edge side, the time offset estimates of multiple events can be arranged according to the event occurrence time, and τc0 and βc can be estimated using linear fitting or recursive filtering. For power frequency phasors, the timescale offset will manifest as a phase offset, therefore... Figure 6The event time difference residuals shown can help the joint estimation model distinguish the relationship between the phase correction coefficient φc and the time scale correction τc0.

[0073] In a specific scenario, a remote closing event occurs on the pole-mounted circuit breaker. A clear inrush current rising edge is observed in the primary current waveform, and a closing position time stamp appears in the secondary terminal SOE record. The edge side follows... Figure 6 (a) Extract the characteristic moments of the rising edge of the inrush flow, and according to Figure 6 (b) Read the SOE closing timescale. After cross-correlation calculation, there is a time difference of about ten milliseconds between the two. If subsequent closing or reclosing events all show similar time differences, the edge side uses this difference as an important basis for the initial timescale correction. If this time difference changes with the running time in an approximately linear trend, the edge side further estimates the timescale drift rate and inputs it into the joint estimation model.

[0074] In another specific scenario, the zero-sequence balance window shows that the zero-sequence current balance residual is consistently large, but Figure 6 The transient events of the switch shown do not exhibit significant timescale drift, and Figure 4 The power flow constraints shown do not exhibit any inconsistencies in the three-phase current amplitude. In this case, the edge side can prioritize identifying potential mismatches in the zero-sequence current channel proportional coefficient or configuration coefficient, and focus calibration on the zero-sequence channel. If zero-sequence balance window anomalies, power flow constraint anomalies, and event time difference residuals occur simultaneously, the edge side will not directly attribute the anomalies to the zero-sequence channel. Instead, it will input multiple types of residuals into the joint estimation model and determine whether automatic application conditions are met through a reliability mechanism.

[0075] In this embodiment, Figure 5 The zero-sequence equilibrium constraint shown is Figure 6 The switch transient event constraints shown are complementary. The zero-sequence balance constraint primarily reflects the electrical consistency between the three-phase channel and the zero-sequence channel, suitable for identifying proportional errors, polarity errors, phase wiring errors, and zero-sequence channel errors; the switch transient event constraint primarily reflects the time consistency between the primary waveform and the secondary event timescale, suitable for identifying initial timescale offset and timescale drift. Both are complementary to... Figure 4 When the distribution network power flow constraints shown are included in the joint estimation model, misjudgments caused by single constraints can be reduced. For example, when only the zero-sequence balance constraint is used, time-scale offset may cause changes in phase angle relationships and manifest as zero-sequence residual anomalies; when the zero-sequence balance constraint is added... Figure 6 After the event time difference constraint is applied, the joint estimation model can preferentially interpret the event as a time-scale correction rather than incorrectly adjusting the zero-sequence channel amplitude.

[0076] To prevent abnormal operating conditions from interfering with zero-sequence and transient constraints, the edge side also sets constraint start / stop conditions in this embodiment. For zero-sequence balance constraints, when a single-phase grounding, arc suppression coil operation, single-phase open circuit, zero-sequence transformer saturation, or zero-sequence channel communication abnormality is detected, the edge side suspends the use of this window for automatic calibration. For switch transient event constraints, when the event waveform amplitude is insufficient, the sampling rate is insufficient, SOE records are missing, the event type cannot be matched, or there is a communication interruption before or after the event, the edge side reduces the event validity component or does not use the event. The above start / stop conditions, together with the credibility calculation, ensure that the edge side only applies the calibration results when the constraint conditions are interpretable.

[0077] Through this embodiment, Figure 5 The A-phase channel, B-phase channel, C-phase channel, zero-sequence channel, three-phase quantity summation, zero-sequence quantity conversion, and balance residual judgment form a zero-sequence consistency calibration link; Figure 6 The transient waveform feature extraction, secondary terminal event record alignment, and event time difference residuals form a time-scale calibration link. The two links provide constraints from electrical balance relationships and event time relationships, respectively, and are consistent with those in Example 2. Figure 4 The power flow constraints shown together constitute the main data source for joint estimation. This processing method enables the present invention to jointly identify and correct the amplitude, phase, and timescale drift of primary and secondary integrated pole-mounted circuit breakers without adding external calibration equipment.

[0078] Example 4 This embodiment describes the module composition and specific implementation of the edge self-calibration device for a primary and secondary integrated pole-mounted circuit breaker. (Refer to...) Figure 2 The device can be deployed in the secondary monitoring and control terminal of the pole-mounted circuit breaker, or in an edge computing unit that communicates with the secondary monitoring and control terminal. Corresponding to the method steps, the device is capable of executing the edge self-calibration process described in Examples 1 to 3.

[0079] Reference Figure 2 In the central part, the edge self-calibration device includes a multi-source data acquisition module, a time buffer and quality marking module, a calibration window filtering module, a distribution network power flow constraint module, a zero-sequence balance constraint module, a switch transient event module, a joint estimation module, a reliability assessment module, and a coefficient management module. These modules can be implemented by different software tasks on the same processor, or by multiple processes, multiple functional units, or multiple embedded services. Different implementation methods do not affect the data flow and processing relationships between the modules.

[0080] The multi-source data acquisition module is used to collect three-phase voltage, three-phase current, zero-sequence voltage, zero-sequence current, switch status, secondary terminal event records, and transient waveform data during the operation of the pole-mounted circuit breaker. (Refer to...) Figure 2On the left, the three-phase current sensor, three-phase voltage sensor, and zero-sequence sensor provide primary-side measurement data to the secondary measurement and control terminal. The switch status acquisition unit provides the secondary measurement and control terminal with the opening and closing status, auxiliary contact changes, and operating circuit status. The communication time synchronization unit provides the secondary measurement and control terminal with the time synchronization status and time reference. The multi-source data acquisition module reads the above data from the secondary measurement and control terminal or its data bus and adds a source identifier and acquisition time to each type of data.

[0081] The multi-source data acquisition module can be implemented in several ways, including a phasor reading unit, a zero-sequence reading unit, an event reading unit, a waveform reading unit, and a time synchronization status reading unit. The phasor reading unit reads the three-phase voltage phasors, three-phase current phasors, active power, reactive power, and frequency output from the secondary terminal. The zero-sequence reading unit reads the zero-sequence voltage, zero-sequence current, and zero-sequence sensor status. The event reading unit reads protection start-up, trip output, closing command, reclosing, switch change, and SOE event records. The waveform reading unit reads transient waveform data before and after opening / closing or fault events. The time synchronization status reading unit reads the status of BeiDou, GPS, network time synchronization, master station time synchronization, or local clock. These units can acquire data through shared memory, file cache, embedded database, IEC communication messages, or internal terminal interfaces.

[0082] The time caching and quality tagging module is used to map the data output from the multi-source data acquisition module to a unified timeline and set data quality tags. (See reference...) Figure 3 This module handles the processing relationships of multiple asynchronous data streams entering a unified control time. For periodic phasor data, it writes it to the corresponding time slice according to the sampling timescale or phasor output timescale. For discrete switch states and SOE events, it establishes indexes according to the event occurrence timescale and event recording timescale, respectively. For transient waveform data, it reconstructs the waveform time axis according to the waveform start time, sampling interval, and sampling point sequence number. Through this module, subsequent constraint calculations can call time-consistent data within the same calibration window.

[0083] The specific implementation of the time buffer and quality marking module may include a time axis management unit, a data buffer unit, an anomaly detection unit, and a quality scoring unit. The time axis management unit maintains unified control time, window boundaries, and local clock status. The data buffer unit stores raw data, corrected data, and quality marking data, and retains a certain length of historical data. The anomaly detection unit identifies situations such as range out-of-bounds errors, continuous fixed values, time rollback, communication interruptions, missing samples, and waveform saturation. The quality scoring unit generates usable, downweighted, or discarded markings based on the anomaly detection results, time synchronization status, and data integrity. The data output by this module includes not only the measurement values ​​themselves but also data reliability information used for subsequent weight configuration.

[0084] The calibration window filtering module is used to filter steady-state calibration windows, zero-sequence equilibrium windows, and switching transient event windows. (See reference...) Figure 1 S2 and Figure 3 The window availability determination module, based on a unified time buffer, identifies which time intervals are suitable for power flow calibration, which for zero-sequence balancing calibration, and which for time-scaled calibration. This module outputs the window type, start and end times, data quality, weight, and exclusion reasons to the subsequent constraint module.

[0085] The calibration window filtering module can be implemented in several ways, including a steady-state window filtering unit, a zero-sequence window filtering unit, and a transient event window filtering unit. The steady-state window filtering unit determines the steady-state calibration window based on switch status, topology status, protection operation status, frequency deviation, load change rate, and phasor validity. The zero-sequence window filtering unit determines the zero-sequence balance window based on zero-sequence magnitude, three-phase unbalance, ground fault flag, arc suppression coil operation status, and zero-sequence channel quality flag. The transient event window filtering unit determines the transient event window based on SOE records, remote control commands, protection operation information, auxiliary contact displacement, and waveform abrupt change characteristics. These units can share the same data buffer but output different window sets.

[0086] The distribution network power flow constraint module is used to construct distribution network power flow constraint residuals based on a steady-state calibration window. (Refer to...) Figure 4 This module reads the relationships between upstream node i, pole-mounted circuit breaker, downstream node j, line impedance Zij, and electrical quantities such as Vi, Iij, Pij, Qij, and Vj to construct branch power balance residuals, node current balance residuals, and voltage drop residuals. The distribution network power flow constraint module does not require complete synchronous measurements on-site. When downstream voltage or adjacent terminal measurements are missing, historical load curves, master station state estimates, or adjacent terminal data can be used to form weak constraints, and the weight of these weak constraints can be reduced.

[0087] The specific implementation of the distribution network power flow constraint module can include a topology reading unit, a line parameter reading unit, a power flow residual calculation unit, and a residual normalization unit. The topology reading unit reads the feeder topology, switch on / off status, and phase connection relationships. The line parameter reading unit reads the line resistance, reactance, line length, and rated parameters. The power flow residual calculation unit calculates the branch power balance residual, node current balance residual, and voltage drop residual based on the voltage, current, and power data within the steady-state calibration window. The residual normalization unit normalizes different residuals according to rated capacity, rated current, rated voltage, or historical stable operating scales, and outputs the distribution network power flow constraint residuals for use by the joint estimation module.

[0088] The zero-sequence balance constraint module is used to construct the zero-sequence balance residual between the three-phase quantities and the zero-sequence quantity based on the zero-sequence balance window. (Refer to...) Figure 5 This module reads data from the A-phase channel, B-phase channel, C-phase channel, and zero-sequence channel, sums the three-phase quantities, and performs configuration coefficient conversion on the zero-sequence quantity to determine whether the balance residual meets the threshold requirements. This module can provide constraints on the proportional error, polarity error, phase connection error, and zero-sequence channel proportional error of the three-phase channels.

[0089] The specific implementation of the zero-sequence balance constraint module may include a zero-sequence configuration reading unit, a three-phase summation unit, a zero-sequence conversion unit, a zero-sequence residual calculation unit, and an error type auxiliary judgment unit. The zero-sequence configuration reading unit reads the zero-sequence sensor output definition and configuration coefficients. The three-phase summation unit calculates the sum of the corrected three-phase current phasors and the corrected three-phase voltage phasors within the same time window. The zero-sequence conversion unit converts the zero-sequence current and zero-sequence voltage quantities based on the configuration coefficients. The zero-sequence residual calculation unit calculates the deviation between the three-phase summation value and the zero-sequence conversion value. The error type auxiliary judgment unit, based on the residual direction, the correlation of the residual with load changes, and the residual changes after phase swapping or polarity reversal, assists in judging possible proportional, phase, polarity, or wiring anomalies, and uses the judgment results as information for reliability calculation and manual verification.

[0090] The switch transient event module is used to construct the event time difference residual between the primary waveform characteristic moment and the secondary terminal event timescale based on the switch transient event window. (Refer to...) Figure 6 This module extracts the primary waveform characteristic moments from the transient waveform and aligns them with the event timestamps in the secondary terminal SOE record or protection action record. This module is primarily used to estimate the initial timestamp correction and timestamp drift rate, and also to help distinguish between phase deviation and timestamp deviation.

[0091] The specific implementation of the switch transient event module may include an event matching unit, a waveform feature extraction unit, a cross-correlation calculation unit, a subsampling interpolation unit, and an event weight calculation unit. The event matching unit determines which type of primary waveform feature corresponds to which type of secondary terminal event timescale in tripping, closing, fault tripping, or reclosing events. The waveform feature extraction unit extracts the start time of abrupt changes, the start time of a drop, the peak time of the transient energy envelope, or the arrival time of oscillation features from the current or voltage waveform. The cross-correlation calculation unit performs correlation calculations on the primary waveform feature sequence and the secondary event sequence to obtain the time delay. The subsampling interpolation unit determines a finer time offset estimate near the correlation peak. The event weight calculation unit determines the event time difference residual weight based on the event amplitude, signal-to-noise ratio, SOE integrity, and waveform sampling rate.

[0092] The joint estimation module estimates the amplitude correction coefficient, phase correction coefficient, initial timescale correction, and timescale drift rate of the measurement channel based on the distribution network power flow constraint residual, zero-sequence balance residual, and event time difference residual. This module receives the distribution network power flow constraint residual from the distribution network power flow constraint module, the zero-sequence balance residual from the zero-sequence balance constraint module, and the event time difference residual from the switch transient event module, and combines this with historical smoothing residuals to comprehensively evaluate the candidate calibration parameters. For the c-th measurement channel, this module can use the amplitude correction coefficient, phase correction coefficient, initial timescale correction, and timescale drift rate as the same set of candidate calibration parameters.

[0093] The joint estimation module can be implemented using a parameter initialization unit, a weight configuration unit, a comprehensive residual construction unit, a solution unit, and a convergence judgment unit. The parameter initialization unit can read the effective coefficients of the previous version, factory calibration coefficients, or candidate coefficients as initial values. The weight configuration unit sets the weights of different residuals based on window quality, constraint type, event validity, and historical stability. The comprehensive residual construction unit normalizes the distribution network power flow constraint residuals, zero-sequence balancing residuals, event time difference residuals, and historical smoothing residuals to form a comprehensive residual. The solution unit can use weighted least squares, recursive least squares, robust estimation, or Kalman filtering to solve the problem. The convergence judgment unit determines the validity of the solution based on parameter changes, residual changes, and the number of iterations. If the solution does not converge or different constraint results conflict, the module's output will not be automatically marked.

[0094] The credibility assessment module generates calibration credibility. This module calculates credibility based on data quality, constraint residuals, event validity, and historical stability, and outputs suggestions to the coefficient management module for automatic application, candidate saving, or alarms. The credibility assessment module does not change the correction coefficients themselves, but rather determines whether the correction coefficients meet the conditions for entering the effective coefficient zone.

[0095] The reliability assessment module can be implemented using a data quality evaluation unit, a residual evaluation unit, an event evaluation unit, a historical stability evaluation unit, and a reliability fusion unit. The data quality evaluation unit calculates data quality components based on data missing rate, sampling integrity, range validity, and time synchronization status. The residual evaluation unit calculates constraint residual components based on the normalized results of distribution network power flow constraint residuals and zero-sequence balance residuals. The event evaluation unit calculates event validity components based on the number of events, event intensity, correlation peak values, and SOE integrity. The historical stability evaluation unit calculates historical stability components based on the differences between correction coefficients obtained from multiple consecutive calibration windows. The reliability fusion unit can use weighted averaging, product fusion, or hierarchical judgment methods to obtain calibration reliability; the specific fusion method is determined by on-site configuration and operation and maintenance strategies.

[0096] The coefficient management module is used to write correction coefficients, save candidate coefficients, or output calibration alarms based on calibration confidence. (See reference...) Figure 2 On the right, this module outputs the corrected measurement data, correction coefficients and version, calibration reliability, and alarms. The coefficient management module also records the version number, source window, event number, generation time, applicable channel, validity period, and rollback coefficients for each correction coefficient. After the correction coefficients are written to the effective area, this module continues to monitor the changes in residuals before and after correction, as well as the status of protection and control data. If the corrected residuals do not decrease or an anomaly occurs, this module performs coefficient rollback and records the reason for the rollback.

[0097] The coefficient management module can be implemented in several ways, including an effective coefficient area, a candidate coefficient area, a historical version area, an audit record unit, and a rollback control unit. The effective coefficient area stores parameters currently involved in measurement correction; the candidate coefficient area stores parameters whose reliability has not yet reached the automatic application threshold but have continued observation value; the historical version area stores coefficient versions that have already taken effect; the audit record unit records the basis for coefficient generation, source window, event number, reliability, and operation status; and the rollback control unit restores the previous version of the coefficients when residuals deteriorate, protection and control systems malfunction, or the master station issues a rollback command.

[0098] Reference Figure 2 The device output of this embodiment includes corrected measurement data, correction coefficients and version, calibration confidence level, and calibration alarm. The corrected measurement data can be used for measurement display, status assessment, master station analysis, and operation monitoring. Whether the protection action logic uses the corrected measurement data can be set hierarchically according to the equipment safety policy. In one implementation, measurement display and status assessment can directly use high-confidence corrected data, and the protection tripping logic can use corrected data after manual confirmation or if permitted by the safety policy. Correction coefficients for low-confidence or candidate states are not included in the protection tripping criteria. This hierarchical approach can reduce the impact of automatic calibration on protection control.

[0099] Reference Figure 7 The device in this embodiment can communicate with the distribution master station or operation and maintenance platform. The communication content may include corrected measurement data, calibration reliability, coefficient version number, source window, event number, alarm type, and rollback status. The distribution master station or operation and maintenance platform can send calibration strategy configuration, threshold configuration, zero-sequence output definition configuration, line parameter configuration, and coefficient rollback commands to the device. If communication is interrupted, the device can still perform data caching, candidate saving, and alarm recording locally; for automatic application strategies, it can decide whether to continue execution based on local security configuration.

[0100] Through this embodiment, the modular implementation method enables the present invention to be deployed in the secondary terminal, edge computing unit or distribution automation field terminal of the primary and secondary integrated pole-mounted circuit breaker, and to achieve edge self-calibration function without changing the existing primary switch body structure.

[0101] Example 5 This embodiment, combined with a field application scenario of power distribution lines, explains the technical requirements, hardware selection, parameter settings, implementation process, and processing effects of the present invention. (Refer to...) Figure 7 Pole-mounted circuit breakers are installed at the sectioning points of the power distribution lines. Figure 7 The horizontal line in the diagram represents the distribution feeder. The primary and secondary fusion pole-mounted circuit breaker installed on the middle tower represents the object being calibrated in this embodiment. The upstream adjacent terminal or master station measurement is located at... Figure 7 On the left, downstream load and adjacent measurements are located Figure 7 On the right, the power distribution master station or operation and maintenance platform is located Figure 7 lower part. Figure 7 The connection relationship extending from the pole-mounted circuit breaker to the secondary measurement and control terminal, edge computing unit, and edge self-calibration device indicates that the present invention does not require additional changes to the primary main circuit structure when deployed in the field. Instead, it obtains operating data and performs calibration calculations through the secondary measurement and control terminal and edge computing unit.

[0102] The power distribution line in this embodiment can be a 10kV overhead feeder or other medium-voltage power distribution lines. Several sectionalizing switches, tie switches, distribution transformers, and user loads are configured on the line. The integrated primary and secondary pole-mounted circuit breaker on the central tower includes a primary switch body, three-phase current sensors, three-phase voltage sensors, zero-sequence current sensors, zero-sequence voltage sensors, a switch status acquisition unit, a secondary measurement and control terminal, an edge computing unit, and a communication unit. The secondary measurement and control terminal has phasor acquisition, SOE recording, fault recording, protection measurement and control, and communication functions. The edge computing unit can be built into the secondary measurement and control terminal or set as an independent computing board in the control box and connected to the secondary measurement and control terminal through the terminal's internal bus or communication interface.

[0103] The technical requirements of this embodiment include: under the conditions that the distribution line is not powered off, the pole-mounted circuit breaker does not exit operation, and no external standard voltage and current source is connected, using field operation data to identify the amplitude deviation, phase deviation and time stamp drift of the three-phase current channel, three-phase voltage channel, zero-sequence channel and event time stamp channel; when the data quality is insufficient, the switch state is unstable, the line topology changes, the zero-sequence is abnormal or the switch transient event is incomplete, the correction coefficient shall not be directly written; after the correction coefficient is written, it shall be able to provide the distribution master station or operation and maintenance platform with calibration credibility, source window, event number, version number and rollback status; in the protection measurement and control function, it shall be able to distinguish the application scope of corrected measurement data for measurement display, state evaluation and protection action according to the security policy.

[0104] reference to Figure 7 the field devices and sensing connection relationships in, the hardware selection can adopt the electronic or low-power current sensor, electronic or capacitive voltage divider type voltage sensor, zero-sequence current sensor, zero-sequence voltage sensor and switch auxiliary contact acquisition circuit that are matched with the primary and secondary integrated complete set of pole-mounted circuit breakers. The secondary measurement and control terminal can have power frequency phasor calculation capability, SOE millisecond-level recording capability and event wave recording capability. The communication unit can use optical fiber, wireless private network, public network encrypted channel or distribution automation dedicated communication channel to connect with the distribution master station or operation and maintenance platform. The time synchronization mode can adopt Beidou, GPS, network time synchronization or master station time synchronization. If high-precision time synchronization cannot be maintained on site for a long time, the present invention can still use the switch transient event to estimate the local time stamp offset and drift rate, but the time synchronization abnormality will be recorded in the data quality component.

[0105] In terms of parameter setting, the length of the steady-state calibration window can be set from 10s to 15min, and the specific value is determined according to the terminal cache capability, load fluctuation level and calibration response speed. For feeders with fast load changes, a shorter window can be used and the number of window requirements can be increased; for feeders with stable load at night, a longer window can be used to reduce the influence of random errors. The length of the switch transient event window can be set to cover the range of 20ms to 10s before and after the event, the short window is used to extract mutation points and zero-crossing changes, and the long window is used to analyze reclosing, inrush current attenuation or transient oscillation. The automatic application threshold can be set to 80 points, and the candidate saving threshold can be set to 60 points; the above thresholds can be adjusted according to the operation and maintenance strategy. The allowable range of the amplitude correction coefficient can be set, for example, 0.80 to 1.20; the allowable range of the phase correction coefficient can be set, for example, -10 degrees to 10 degrees; the allowable range of the initial time stamp correction amount can be set, for example, -200ms to 200ms; the allowable range of the time stamp drift rate can be set, for example, -100ppm to 100ppm. The above ranges are used for engineering protection and abnormality interception, and can be narrowed according to the equipment level in actual application.

[0106] During field operation, reference to Figure 7 The three-phase current sensor, three-phase voltage sensor, and zero-sequence sensor transmit primary-side operational measurements to the secondary control terminal. The switch status acquisition unit transmits opening, closing, and auxiliary contact change information to the secondary control terminal. The secondary control terminal generates phasor data, event logs, and transient waveform data. After reading the above data, the edge self-calibration device... Figure 3 The device employs a unified time buffer and quality marking mechanism. When communication interruption, sampling loss, time synchronization anomaly, or waveform saturation occurs during a certain period, the device records the anomaly level in the quality marking and determines whether the data should participate in automatic calibration based on the anomaly level.

[0107] In a normal load operation scenario, the pole-mounted circuit breaker remains in the closed state for an extended period, the feeder topology is stable, no protection actions occur, and the load change rate is below a preset threshold. The edge self-calibration device operates according to... Figure 1 S2 in the process filters multiple steady-state calibration windows, and follows the... Figure 4 The relationships shown are used to read the electrical relationships between upstream node i, pole-mounted circuit breaker, downstream node j, line impedance Zij, and Vi, Iij, Pij, Qij, and Vj. If... Figure 4 If the branch power balance residuals and voltage drop residuals all point to a low amplitude of the B-phase current channel in multiple windows, and the window quality score meets the requirements, then the joint estimation model will adjust the B-phase current amplitude correction coefficient to increase. If, during the same time period... Figure 5 The zero-sequence balance residuals did not indicate phase connection or polarity abnormalities. Figure 6 If the event time difference residuals do not show a significant timescale offset, the confidence assessment module will increase the confidence of the amplitude correction result.

[0108] In a zero-order channel anomaly scenario, refer to Figure 5 The edge self-calibration device detected a stable deviation between Ia'+Ib'+Ic' and kI·I0' within multiple zero-sequence balance windows, while the power flow residuals between the three-phase currents did not show significant amplitude inconsistencies. The device further determined that the zero-sequence current channel proportional coefficient or configuration coefficient might have a deviation. At this point, if the distribution line has no single-phase grounding, no arc suppression coil operation, no single-phase open circuit marker, and the zero-sequence channel quality marker is usable, the device can generate a candidate correction coefficient for the zero-sequence channel. If this candidate correction coefficient reduces the zero-sequence balance residual in subsequent windows and the confidence level reaches the automatic application threshold, the coefficient management module writes it into the effective coefficient area; if the confidence level only reaches the candidate saving threshold, it continues to be observed without automatic application.

[0109] In a switching transient event scenario, refer to Figure 6When a reclosing event occurs at a pole-mounted circuit breaker, the secondary terminal records the protection trip time stamp, reclosing time stamp, and switch position change time stamp, while also saving the transient current and voltage waveforms before and after the event. The edge self-calibration device extracts the current abrupt change time, voltage drop time, and inrush current rising edge time from the primary waveform and matches them with the SOE records of the secondary terminal. If the cross-correlation result shows a stable offset of the secondary event time stamp relative to the characteristic time of the primary waveform, the device uses this offset as the initial time stamp correction amount; if this offset gradually changes over time in subsequent events, the device further estimates the time stamp drift rate. This estimation result, after being incorporated into the joint estimation model, can help distinguish between power frequency phase angle deviation and secondary terminal time stamp deviation.

[0110] During coefficient writing and communication interaction, refer to Figure 7 At the bottom, the edge self-calibration device sends the corrected measurement data, calibration confidence level, coefficient version number, and calibration alarms to the distribution master station or operation and maintenance platform. The distribution master station or operation and maintenance platform can issue threshold configuration, line parameter configuration, zero-sequence output definition configuration, and coefficient rollback commands. When communication is normal, the master station can display the current correction coefficients, confidence levels, and nearest source windows for each measurement channel. When communication is interrupted, the edge self-calibration device still performs caching, candidate saving, and alarm recording locally; whether automatic application continues can be determined by local security policies. If the master station issues a rollback command, the coefficient management module restores the previous version of the coefficients and records the rollback reason in the audit log.

[0111] To illustrate the processing effect of the technical solution of this invention, this embodiment uses operational data generated by the same pole-mounted circuit breaker under the same feeder topology, line parameters, sensor configuration, and communication time synchronization conditions as the basis for analysis. The comparison is between the conventional processing method and the processing method of this invention. The conventional processing method refers to using data solely based on the original measurements from secondary terminals, single threshold alarms, and manual periodic verification results; it does not jointly generate correction coefficients based on distribution network power flow constraints, zero-sequence balance constraints, and switch transient event constraints. The processing method of this invention refers to, based on the same input data, according to... Figure 1 The process shown completes time caching, quality marking, window filtering, constraint residual construction, joint estimation, and confidence-driven coefficient management.

[0112] The above comparative analysis uses the same batch of historical operating data for offline replay or parallel field observation. During offline replay, both the conventional processing method and the method of this invention read the same three-phase voltage, three-phase current, zero-sequence quantity, SOE records, and transient waveform data, and both use the same window start and end times, the same outlier removal rules, and the same line parameters. During parallel field observation, the conventional processing method is only used as a comparison calculation path and does not issue control commands to the protection and control system; the method of this invention only writes correction coefficients when the reliability meets the automatic application threshold. This setup avoids incomparable comparison results due to differences in load levels, topology status, event types, or sampling conditions.

[0113] The comparison metrics include comprehensive normalized residual, calibration reliability, timescale deviation estimate, anomaly handling path, and amplitude correction coefficient stability. The comprehensive normalized residual is obtained by fusing distribution network power flow residual, zero-sequence balance residual, and event time difference residual according to their corresponding weights, and is used to evaluate the consistency between the measurement link and operational constraints. Calibration reliability is obtained by fusing data quality components, constraint residual components, event validity components, and historical stability components. The timescale deviation estimate is obtained from the cross-correlation matching results between the primary waveform characteristic time and the secondary terminal event timescale. Anomaly handling paths are recorded according to four status categories: available, downweighted, candidate saved, and alarm. The stability of the amplitude correction coefficient is evaluated by the range of variation of the correction coefficient in the same channel within consecutive calibration batches. Figure 8 The curves and matrices provided are used to express the above evaluation methods and trend relationships. The values ​​can be recalculated based on actual line data and should not be interpreted as test results that are fixed and applicable to all field equipment.

[0114] Reference Figure 8 This embodiment also illustrates the processing effect after applying the present invention. Figure 8 The top-left subplot illustrates the trend of constraint residual changes. The uncorrected composite residual represents the normalized residual calculated from the original measurement data using conventional processing methods. The corrected composite residual represents the normalized residual recalculated using the processing method of this invention after writing or simulating the writing of correction coefficients. The horizontal axis of this subplot represents the calibration windows arranged in chronological order, and the vertical axis represents the composite residual normalized to rated capacity, rated current, rated voltage, or event time difference scales. Because the two curves use the same batch of window data, the same line parameters, and the same residual normalization method, they can be used to illustrate the impact of multi-constraint joint estimation on measurement consistency. Figure 8 The values ​​in the upper left subgraph are schematic normalized results. In actual implementation, they should be recalculated based on the data collected on site and the preset weights.

[0115] Figure 8The top right subplot illustrates the convergence of confidence and timescale deviation, with data sourced from the same batch of switch transient event windows. The calibration confidence curve is obtained by fusing data quality components, constraint residual components, event validity components, and historical stability components. The timescale deviation curve is obtained by... Figure 6 The cross-correlation matching results between the characteristic moments of the primary waveform and the timescales of the secondary terminal events are shown. As the number of valid events increases, if the time offset estimates of multiple events are consistent, the confidence level can increase, and the timescale deviation estimate can tend to stabilize. If the quality of subsequent events deteriorates, SOE records are missing, or time offset estimates between different events conflict, the confidence level curve can decrease, and the system will correspondingly switch to the candidate saving or alarm path. This sub-figure is used to illustrate the evaluation process of timescale calibration, rather than claiming that all sites achieve the same convergence value.

[0116] Figure 8 The lower left subplot illustrates the anomaly levels and processing paths. Its matrix cells represent the processing path selection rules for different anomaly scenarios. Data missing, weak events, constraint conflicts, and interlocking anomalies correspond to different data reliability and security risk levels, respectively. Normal, reduced weight, candidate, and alarm correspond to directly participating in the calculation, participating in the calculation after reducing weight, saving candidate coefficients and continuing observation, and not writing coefficients and outputting an alarm, respectively. This subplot is not a comparison of single numerical indicators, but a graphical representation of anomaly handling rules. Through this processing path, Figure 8 Trend analysis in the top left and top right subplots will not be directly converted into effective coefficients when data quality is insufficient or security conditions are not met, thereby reducing the risk of misjudgment due to insufficient comparative data.

[0117] Figure 8 The lower right sub-figure illustrates the stable range of the amplitude correction coefficient. The horizontal axis represents consecutive calibration batches, and the vertical axis represents the amplitude correction coefficient for the same measurement channel. The allowable range in this sub-figure is determined by the equipment accuracy level, factory calibration range, and on-site maintenance strategy. The schematic curve illustrates the method for determining whether the correction coefficient tends to stabilize and remain within the allowable range after multiple calibration batches. Before the correction coefficient enters the effective range, the edge self-calibration device needs to simultaneously determine whether it is within the allowable range, whether the change in coefficient relative to the previous version meets the safety policy, and whether the overall residual after correction has not deteriorated. If the correction coefficient exceeds the allowable range, even if the residual in a certain window decreases, it should be switched to an alarm or manual confirmation path. This sub-figure illustrates that the coefficient management module not only saves the correction results but also constrains the stability, source conditions, and applicable scope of the correction results.

[0118] In a specific execution example, after a 10kV overhead feeder pole-mounted circuit breaker had been operating for a period of time, the edge self-calibration device detected that the branch power balance residuals involved in the calculation of the A-phase current channel were consistently high in multiple steady-state windows, while the voltage drop residuals pointed in the same direction. The device combined the zero-sequence balance window and the switch transient event window for joint estimation, obtaining an A-phase current channel amplitude correction coefficient of 1.018, a phase correction coefficient of -0.4 degrees, an initial timescale correction of 3.2 ms, a timescale drift rate of 2 ppm, and a calibration confidence score of 86. Since the confidence score reached the automatic application threshold, the coefficient management module wrote this set of coefficients into the effective coefficient area and recorded the source window and event number. After writing, the device continued to monitor the constraint residual changes. If the comprehensive residuals remained decreasing or stable in the subsequent three steady-state windows, the current version of the coefficients was maintained; if the comprehensive residuals increased, the previous version of the coefficients was restored.

[0119] In another specific example of the processing effect, the transient waveform in a certain reclosing event was not completely preserved. The SOE record still existed, but the event cross-correlation peak was low. The edge self-calibration device could calculate the event time difference residual, but the event validity component was low. If both power flow constraints and zero-sequence constraints did not form sufficiently consistent correction directions, the calibration reliability might only reach the candidate preservation threshold. In this case, the coefficient management module did not write the correction coefficients into the effective area, but instead saved the candidate coefficients and sent the candidate status and continued observation information to the distribution master station or maintenance platform. This processing result corresponds to... Figure 8 The candidate paths in the algorithm can avoid directly applying calibration results when the event quality is insufficient.

[0120] This embodiment can also be applied to scenarios involving feeder power transfer or large load fluctuations. When a feeder power transfer operation occurs... Figure 7 The relationships between upstream nodes, downstream nodes, and branches may change. The device suspends the use of data from the transfer period to construct steady-state power flow constraints based on these topology changes. Once the transfer is complete and the topology stabilizes, the device rereads line parameters and measurements from adjacent terminals to resume operation. Figure 4 The power flow residual calculation is shown. During daytime periods with large load fluctuations, the device can reduce the steady-state window weight and rely more on the zero-sequence balance window and switching transient event window; during nighttime periods with relatively stable loads, the device can increase the power flow constraint weight. Through dynamic weight configuration, this invention can adapt to the data characteristics of different operating periods.

[0121] As can be seen from this embodiment, Figure 7 This demonstrates the deployment relationship of the invention in a power distribution line field. Figure 8This paper demonstrates the effectiveness of the present invention in handling constraint residuals, reliability, abnormal paths, and the stability of correction coefficients. The application illustrates that the present invention can perform edge self-calibration of amplitude, phase, and timescale drift between primary sensors and secondary terminals under conditions of uninterrupted operation of the pole-mounted circuit breaker, and controls automatic application risks through reliability, candidate saving, alarm, and rollback mechanisms. The specific line voltage level, window length, threshold range, sensor model, communication method, and time synchronization method can all be adjusted according to field equipment conditions. As long as the processing relationships of multi-source data time caching, calibration window filtering, distribution network power flow constraints, zero-sequence balance constraints, switch transient event constraints, joint estimation, and reliability-driven coefficient management are still employed, they all fall under the implementation methods of the present invention.

[0122] The embodiments described above are used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. For those skilled in the art, equivalent substitutions or adaptive adjustments can be made to the data acquisition method, window filtering conditions, residual construction method, weight configuration method, reliability calculation method, module deployment location, communication interface form, and coefficient management strategy without departing from the technical concept of the present invention. All equivalent technical solutions based on the distribution network power flow constraints, zero-sequence balance relationship, and switch transient events described in this invention to jointly achieve edge self-calibration of primary and secondary integrated pole-mounted circuit breakers should be included within the scope of protection of this invention.

Claims

1. A method for edge self-calibration of a primary and secondary integrated pole-mounted circuit breaker, characterized in that, include: S1 collects three-phase voltage, three-phase current, zero-sequence voltage, zero-sequence current, switch status, secondary terminal event records, and transient waveform data during the operation of the pole-mounted circuit breaker, and performs unified time buffering and quality marking on the collected data. S2, based on the switch status, topology status, load fluctuation, zero-sequence abnormal status and time synchronization status, filter the steady-state calibration window, zero-sequence balance window and switch transient event window from the data; S3, construct the power flow constraint residual of the distribution network based on the steady-state calibration window, construct the zero-sequence balance residual between the three-phase quantity and the zero-sequence quantity based on the zero-sequence balance window, and construct the event time difference residual between the primary waveform characteristic moment and the secondary terminal event time scale based on the switch transient event window; S4. Input the power flow constraint residual, zero-sequence balance residual and event time difference residual into the joint estimation model to obtain the amplitude correction coefficient, phase correction coefficient, initial time scale correction amount and time scale drift rate of the measurement channel; S5 generates calibration confidence based on data quality, constraint residuals, event validity, and historical stability, and writes correction coefficients, saves candidate coefficients, or outputs calibration alarms based on the calibration confidence.

2. The edge self-calibration method for a primary and secondary integrated pole-mounted circuit breaker according to claim 1, characterized in that, The unified time caching and quality marking of the collected data in S1 includes: mapping phasor data, zero-sequence data, switch state data, event record data, and transient waveform data with different sampling frequencies to the same time axis according to the unified control time of the secondary terminal; recording the sampling frequency, clock source, time synchronization status, communication status, range status, and waveform integrity for each data entry; setting an anomaly level for the corresponding data when the data has time bounce, continuous fixedness, range out-of-bounds, sampling loss, communication interruption, or sensor saturation; removing the corresponding data from the automatic calibration calculation when the anomaly level exceeds the preset usable level, and retaining the corresponding data and reducing its weight in subsequent constraint calculations when the anomaly level does not exceed the preset usable level.

3. The edge self-calibration method for a primary and secondary integrated pole-mounted circuit breaker according to claim 1, characterized in that, The steady-state calibration window selection in S2 includes: calculating the load change rate, power factor change rate, and phasor effectiveness score within a time interval where the switch opening / closing status remains unchanged, the feeder topology remains unchanged, no protection actions occur, the frequency deviation is within the allowable range, and no sudden changes occur in the three-phase voltage and three-phase current; when the load change rate, power factor change rate, and phasor effectiveness score meet the steady-state window conditions, this time interval is used as the steady-state calibration window; when there are remote control operations, fault trips, reclosing, single-phase grounding disturbances, transformer saturation, or master station time synchronization anomalies, this time interval is excluded from the steady-state calibration window or downweighted.

4. The edge self-calibration method for a primary and secondary integrated pole-mounted circuit breaker according to claim 1, characterized in that, The construction of distribution network power flow constraint residuals in S3 includes: calculating branch power balance residuals, node current balance residuals, and voltage drop residuals based on the line impedance, phase connection relationship, switch topology status, and phasor data of the feeder where the pole-mounted circuit breaker is located; among them, the branch power balance residual represents the deviation between the corrected active power and reactive power and the power calculated from voltage, current, and phase angle; the node current balance residual represents the deviation between the current entering and leaving the node; and the voltage drop residual represents the deviation between the branch head voltage, branch current, line impedance, and branch end voltage; when upstream or downstream measurement data is missing, historical load curves or adjacent terminal measurements are used to form weak constraints, and the residual weight corresponding to the weak constraints is reduced.

5. The edge self-calibration method for a primary and secondary integrated pole-mounted circuit breaker according to claim 1, characterized in that, The construction of zero-sequence balance residuals in S3 includes: establishing the relationship r_zero_I=Îa+Îb+Îc-k_IÎ0 for the current channel and the relationship r_zero_U=Ûa+Ûb+Ûc-k_UÛ0 for the voltage channel, where Îa, Îb, and Îc represent the corrected three-phase current phasors, Î0 represents the corrected zero-sequence current, Ûa, Ûb, and Ûc represent the corrected three-phase voltage phasors, Û0 represents the corrected zero-sequence voltage, and k_I and k_U are configuration coefficients corresponding to the zero-sequence sensor output definition; when the zero-sequence quantity is a residual current or residual voltage output, the configuration coefficients are taken as values ​​matching the residual current or residual voltage definition; when the zero-sequence quantity is a symmetrical component output, the configuration coefficients are taken as values ​​matching the symmetrical component definition; and the three-phase channel proportional error, polarity error, phase connection error, and zero-sequence channel proportional error are identified based on the zero-sequence balance residuals.

6. The edge self-calibration method for a primary and secondary integrated pole-mounted circuit breaker according to claim 1, characterized in that, The construction of event time difference residuals in S3 includes: when a tripping, closing, fault tripping, or reclosing event occurs, extracting the moment of current change, voltage drop, peak moment of transient energy envelope, or arrival moment of oscillation characteristics from transient waveform data, and reading the protection start time stamp, switch change time stamp, and event sequence record time stamp from the secondary terminal event record; performing cross-correlation calculation on the primary waveform feature sequence and the secondary terminal event sequence to obtain the time delay corresponding to the correlation peak; when there are multiple sampling points near the correlation peak, using interpolation to determine the subsampling level time delay; using the difference between the time delay and the current channel time stamp correction amount as the event time difference residual, and determining the weight of the event time difference residual based on the event amplitude, signal-to-noise ratio, and event record integrity.

7. The edge self-calibration method for a primary and secondary integrated pole-mounted circuit breaker according to claim 1, characterized in that, In S4, the joint estimation model uses the amplitude correction coefficient, phase correction coefficient, initial time scale correction, and time scale drift rate of each measurement channel as calibration parameters to be determined. Under the action of the candidate calibration parameters, candidate corrections are performed on the amplitude, phase, and time position of the phasor data, and candidate corrections are performed on the time axis of the transient waveform data. The residuals of distribution network power flow constraints, zero-sequence balance, and event time difference after the candidate corrections are calculated respectively, and corresponding weights are set according to data quality, constraint type, and event validity. When the overall residual meets the convergence condition and the change of the candidate calibration parameter relative to the previous effective version is within a safe range, the candidate calibration parameter is output as the correction coefficient of the corresponding measurement channel.

8. The edge self-calibration method for a primary and secondary integrated pole-mounted circuit breaker according to claim 1, characterized in that, In S5, generating calibration reliability includes: calculating data quality components based on data missing rate, range validity, sampling integrity, and time synchronization status; calculating constraint residual components based on the normalized results of distribution network power flow constraint residuals and zero-sequence balance residuals; calculating event validity components based on the number of switch transient events, event intensity, cross-correlation peak value, and event record integrity; and calculating historical stability components based on the differences between correction coefficients obtained from multiple consecutive calibration windows. These components are then fused to obtain calibration reliability C. When C reaches the automatic application threshold, the amplitude correction coefficient, phase correction coefficient, initial timescale correction, and timescale drift rate are written into the effective coefficient area, and the version number, source window, and event number are recorded. When C reaches the candidate saving threshold but is lower than the automatic application threshold, the corresponding correction coefficients are saved to the candidate coefficient area and observation is extended. When C is lower than the candidate saving threshold, a calibration alarm is output without writing correction coefficients.

9. A self-calibrating device for the edge of a primary and secondary integrated pole-mounted circuit breaker, characterized in that, It includes a multi-source data acquisition module, a time buffer and quality labeling module, a calibration window filtering module, a distribution network power flow constraint module, a zero-sequence balance constraint module, a switch transient event module, a joint estimation module, a reliability assessment module, and a coefficient management module; The multi-source data acquisition module is used to acquire three-phase voltage, three-phase current, zero-sequence voltage, zero-sequence current, switch status, secondary terminal event records, and transient waveform data during the operation of the pole-mounted circuit breaker. The time caching and quality marking module is used to map the collected data to a unified time axis and set quality markings; The calibration window filtering module is used to filter steady-state calibration windows, zero-sequence equilibrium windows, and switching transient event windows. The distribution network power flow constraint module is used to construct the distribution network power flow constraint residual based on the steady-state calibration window; the zero-sequence balance constraint module is used to construct the zero-sequence balance residual between the three-phase quantity and the zero-sequence quantity based on the zero-sequence balance window. The switch transient event module is used to construct the event time difference residual between the primary waveform characteristic moment and the secondary terminal event time scale based on the switch transient event window; The joint estimation module is used to estimate the amplitude correction coefficient, phase correction coefficient, initial timescale correction amount, and timescale drift rate of the measurement channel based on the distribution network power flow constraint residual, zero-sequence balance residual, and event time difference residual. The credibility assessment module is used to generate calibration credibility; the coefficient management module is used to write correction coefficients, save candidate coefficients or output calibration alarms based on the calibration credibility.

10. A primary and secondary integrated pole-mounted circuit breaker, characterized in that, The system includes a primary switch body, three-phase current sensors, three-phase voltage sensors, a zero-sequence sensor, a switch status acquisition unit, a secondary measurement and control terminal, an edge computing unit, and a communication unit. The three-phase current sensors, three-phase voltage sensors, and zero-sequence sensor are connected to the primary switch body and are used to collect feeder operation measurement data. The switch status acquisition unit is used to collect open status, closed status, and switch change information. The secondary measurement and control terminal is used to generate phasor data, event records, and transient waveform data. The edge computing unit is equipped with the edge self-calibration device for the integrated primary and secondary pole-mounted circuit breaker as described in claim 9, and is used to output corrected measurement data, correction coefficients, calibration reliability, and calibration alarms. The communication unit is used to send the corrected measurement data, calibration reliability, coefficient version number, and calibration alarms to the distribution master station or operation and maintenance platform, and to receive calibration strategy configuration, threshold configuration, and coefficient rollback instructions from the distribution master station or operation and maintenance platform.

Images