A current transformer magnetic saturation fault-tolerant processing method and system

Abstract

The application discloses a current transformer magnetic saturation fault-tolerant processing method and system, relates to the technical field of power system distribution network automation, and comprises the following steps: acquiring a multi-phase current signal and a voltage signal; determining whether a current transformer is in a magnetic saturation state based on at least one of amplitude characteristics, sampling limit characteristics and waveform distortion characteristics of the multi-phase current signal, in combination with voltage drop characteristics of the voltage signal; in response to determining that the current transformer is in the magnetic saturation state, setting a memory identifier of an overcurrent fault; and in response to detecting that a line is in a state of no voltage and no current and the memory identifier of the overcurrent fault is in a set state, performing output of the overcurrent signal and resetting the memory identifier of the overcurrent fault. The application effectively distinguishes the magnetic saturation from interference signals, avoids misoperation and solves the problem of missing overcurrent signal output.

Description

Technical Field

[0001] This invention belongs to the field of power system distribution network automation technology, specifically relating to a method and system for handling magnetic saturation fault tolerance of current transformers. Background Technology

[0002] In distribution network automation systems, feeder automation (FA) relies on current signals collected by current transformers (CTs) for fault location and isolation. However, when a short-circuit fault occurs in the distribution network, the short-circuit current may far exceed the linear operating range of the CT, causing the CT to enter a magnetic saturation state. CT magnetic saturation causes severe distortion of the secondary current waveform and a significant attenuation of the fundamental component, making it impossible for the distribution terminal to accurately identify overcurrent faults, resulting in missed overcurrent signals, switch failures, or FA system misjudgments. In existing technologies, CT magnetic saturation detection often relies on single harmonic characteristics or amplitude characteristics, which can easily misjudge interference signals such as transformer inrush current as magnetic saturation. At the same time, existing solutions lack a safe retransmission mechanism in coordination with the FA master station. If a signal is directly retransmitted after magnetic saturation causes signal loss, it may cause protection malfunctions; if no retransmission is made, fault location will be inaccurate, making it difficult to balance safety and reliability. Summary of the Invention

[0003] To address the shortcomings of existing technologies, the present invention aims to provide a method and system for handling magnetic saturation faults in current transformers, enabling accurate identification of magnetic saturation states and reliable retransmission of overcurrent signals while ensuring safety.

[0004] This invention provides a method for handling magnetic saturation fault tolerance in current transformers, comprising:

[0005] Acquire multiphase current and voltage signals;

[0006] Based on at least one of the amplitude characteristics, sampling limit characteristics, and waveform distortion characteristics of at least one phase current signal in the multiphase current signal, combined with the voltage drop characteristics of the voltage signal, it is determined whether the current transformer is in a magnetic saturation state.

[0007] In response to determining that the current transformer is in the magnetic saturation state, the overcurrent fault memory flag is set;

[0008] In response to the detection that the line is in a state of no voltage and no current and the overcurrent fault memory flag is in a set state, the overcurrent signal is retransmitted and the overcurrent fault memory flag is reset.

[0009] After receiving the overcurrent signal retransmission output, the distribution terminal uploads the signal to the distribution network system master station. The master station then uses the overcurrent signal and the FA fault location logic to determine the fault range.

[0010] The method for determining whether a current transformer is in a magnetic saturation state employs three detection algorithms: high current detection, analog-to-digital conversion saturation detection, and waveform feature detection.

[0011] Optionally, high current detection, analog-to-digital conversion saturation detection, and waveform feature detection are performed in parallel. In the high current detection, when the fundamental effective value of at least two phase current signals in the multi-phase current signals is greater than a preset current initiation threshold, and the corresponding fundamental effective value of the line voltage is less than a preset voltage threshold, the current transformer is determined to be in the magnetic saturation state. In the analog-to-digital conversion saturation detection, when the absolute value of at least two phase current signals within a single power frequency cycle is greater than a preset positive limit threshold, and the absolute value of the corresponding line voltage is less than a preset negative limit threshold, and the corresponding line voltage is less than a preset voltage threshold, the current transformer is determined to be in the magnetic saturation state. When the effective value of the fundamental wave is less than the preset voltage threshold, the current transformer is determined to be in the magnetic saturation state. In the waveform feature detection, when the effective value of the fundamental wave of at least two phase current signals is greater than the preset current feature threshold, the absolute values ​​of the forward and reverse peak values ​​are both greater than the preset peak threshold, the effective value of the corresponding line voltage fundamental wave is less than the preset voltage threshold, and the third harmonic content is greater than the preset harmonic threshold, the current transformer is determined to be in the magnetic saturation state. Wherein, if any one of the high current detection, the analog-to-digital conversion saturation detection, and the waveform feature detection meets the condition, the current transformer is determined to be in the magnetic saturation state.

[0012] In the high current detection, the preset current start-up threshold is a preset start-up multiple of the current rating; in the analog-to-digital conversion saturation detection, the absolute values ​​of the preset positive limit threshold and the preset negative limit threshold are equal, and correspond to the analog-to-digital conversion sampling value of the current transformer at its maximum range; the preset number is a preset sampling ratio of the total sampling points of a single power frequency cycle; when the absolute values ​​of the analog-to-digital conversion sampling values ​​of the at least two phase current signals within the single power frequency cycle are such that the absolute values ​​of the preset number of sampling points are greater than the preset positive limit threshold, and the absolute values ​​of the preset number of sampling points are such that the absolute values ​​are less than the preset negative limit threshold, the conditions for the analog-to-digital conversion saturation detection are determined to be met.

[0013] The preset current characteristic threshold is a preset characteristic multiple of the current rating; the preset peak threshold is a preset peak multiple of the preset current characteristic threshold; the preset harmonic threshold is a preset harmonic percentage; in the waveform characteristic detection, it is required that the absolute values ​​of the positive peak and the negative peak of the at least two phase current signals are both greater than the preset peak threshold to characterize the symmetry of waveform distortion, and the percentage of the third harmonic content of the at least two phase current signals relative to the fundamental wave is greater than the preset harmonic threshold.

[0014] The system monitors the line voltage and three-phase current of the line in real time. When the effective value of the line voltage is less than a preset no-voltage threshold and the effective values ​​of the three-phase currents are all less than a preset no-current threshold, and this state continues for more than a preset confirmation time, the line is determined to be in the no-voltage and no-current state. When it is determined that the current transformer is in the magnetic saturation state, the overcurrent fault general flag and the overcurrent fault memory flag are set. When it is determined that the current transformer is not in the magnetic saturation state, the overcurrent fault general flag is immediately reset, and the overcurrent fault memory flag is reset after a preset delay. When the overcurrent fault memory flag is set and the line is detected to be in the no-voltage and no-current state, the overcurrent signal is immediately retransmitted, and the overcurrent fault memory flag is immediately reset.

[0015] The overcurrent compensation flag is set, a hard contact closure signal is output, and an event sequence record signal is sent to the master station system; the overcurrent compensation flag is automatically reset after a preset holding time to restore the initial state; wherein, the preset holding time is greater than the hard remote signaling detection debounce time of the power distribution terminal.

[0016] After the overcurrent signal is re-transmitted, the process also includes terminal-side signal processing and uploading steps. The terminal-side signal processing and uploading steps can be performed in any of the following ways: Method 1: The original overcurrent signal and the overcurrent re-transmission signal are ORed within the distribution terminal to generate a fused overcurrent signal and uploaded to the master station system; Method 2: A magnetic saturation re-transmission overcurrent remote signaling point is added to the existing remote signaling points of the distribution terminal, and the master station system performs equivalent processing on the magnetic saturation re-transmission overcurrent remote signaling point and the original overcurrent signal.

[0017] This invention also provides a current transformer magnetic saturation fault-tolerant processing system, comprising: a current transformer magnetic saturation detection module configured to acquire multi-phase current signals and voltage signals, and determine whether the current transformer is in a magnetic saturation state based on at least one of the amplitude characteristics, sampling limit characteristics, and waveform distortion characteristics of at least one phase current signal in the multi-phase current signals, combined with the voltage drop characteristics of the voltage signals; a distribution terminal configured to, in response to determining that the current transformer is in the magnetic saturation state, set an overcurrent fault memory flag; and in response to detecting that the line is in a state of no voltage and no current and the overcurrent fault memory flag is set, execute a supplementary overcurrent signal output and reset the overcurrent fault memory flag; a master station system configured to receive overcurrent information uploaded by the distribution terminal and perform fault range judgment; wherein, the current transformer magnetic saturation detection module and the distribution terminal share the voltage transformer and the secondary output signal of the current transformer of the primary switch.

[0018] The above system achieves decoupling of magnetic saturation detection and signal retransmission through a modular architecture, supports external deployment or software upgrade integration, and solves the problem of difficult replacement of the CT body of existing distribution network equipment.

[0019] In addition, the present invention provides a computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the current transformer magnetic saturation fault-tolerant processing method as described above.

[0020] In addition, the present invention also provides a power distribution terminal device, including: a processor; a memory for storing a computer program; wherein, when the processor executes the computer program, it implements the current transformer magnetic saturation fault-tolerant processing method as described above.

[0021] This invention discloses a method and system for handling magnetic saturation fault tolerance in current transformers. By integrating multi-dimensional features such as current amplitude, sampling limits, and waveform distortion with voltage drop characteristics for composite judgment, it overcomes the shortcomings of traditional single-feature detection, which is susceptible to interference from inrush current and other factors, significantly improving the accuracy of magnetic saturation identification. Based on this, an innovative safety retransmission mechanism based on overcurrent fault memory and no-voltage / no-current state triggering is designed. The signal retransmission action is strictly limited to after the fault has been cleared by the upstream switch, solving the problem of missed overcurrent signals caused by CT saturation and completely avoiding the risk of protection malfunction caused by erroneous retransmission during the fault's duration. Furthermore, the system architecture is compatible with existing distribution network equipment, requiring no replacement of the CT itself or large-scale modification of the FA master station; fault tolerance can be achieved only through software upgrades or external modules, demonstrating high engineering practical value and promising prospects for widespread application. Attached Figure Description

[0022] Figure 1 This is a schematic flowchart of the current transformer magnetic saturation fault-tolerant processing method according to an embodiment of this application;

[0023] Figure 2 This is a schematic diagram of the overall architecture of the current transformer magnetic saturation fault-tolerant processing system according to an embodiment of this application;

[0024] Figure 3 This is a schematic diagram of the power distribution terminal software upgrade system architecture and functional modules according to an embodiment of this application;

[0025] Figure 4 This is a schematic diagram of the internal functional modules of the CT magnetic saturation detection module in an embodiment of this application. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0027] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0028] like Figure 1 As shown, this embodiment provides a method for handling magnetic saturation faults in current transformers. This method aims to solve the problem of overcurrent signal leakage caused by magnetic saturation of current transformers and the resulting misjudgment in feeder automation systems. This embodiment constructs a higher-level logic framework for magnetic saturation identification and safety signal retransmission from an overall process perspective, specifically including the following steps.

[0029] Step S100: Acquire multiphase current and voltage signals. Specifically, this step is the fundamental data source for all subsequent analysis and control. The multiphase current signal typically comes from the secondary output of the current transformer on the primary switch side, reflecting the current load or fault current state of the line; the voltage signal typically comes from the secondary output of the voltage transformer, reflecting the voltage level of the line. In practical applications, the acquired analog signals need to undergo analog-to-digital conversion and necessary digital filtering preprocessing to eliminate the impact of on-site electromagnetic interference on subsequent feature extraction. It should be understood that although this embodiment uses a distribution network scenario as an example, this signal acquisition method is also applicable to other power monitoring and protection scenarios where there is a risk of magnetic saturation of current transformers.

[0030] Step S200: Based on at least one of the amplitude characteristics, sampling limit characteristics, and waveform distortion characteristics of at least one phase current signal in the multi-phase current signal, combined with the voltage drop characteristics of the voltage signal, determine whether the current transformer is in a magnetic saturation state. This step is the core of this application's accurate identification. Specifically, when a current transformer is magnetically saturated, its secondary output often exhibits various abnormal forms, such as an abnormally large increase in the fundamental amplitude, clipping of the sampled value when it reaches the range limit, or severe waveform distortion containing a large number of harmonics. However, relying solely on a single current characteristic can easily misjudge non-fault interferences such as transformer inrush current and motor starting current as magnetic saturation. Therefore, this application innovatively introduces the voltage drop characteristics of the voltage signal as an auxiliary criterion. From a physical mechanism perspective, when a true short-circuit fault leads to magnetic saturation, it is inevitably accompanied by a significant drop in line voltage; while when most non-fault interferences occur, the system voltage usually remains normal or only exhibits fluctuations in a specific pattern. Therefore, by logically combining the multidimensional anomaly characteristics of current with voltage drop characteristics, it is possible to fundamentally distinguish between fault-related magnetic saturation and non-fault-related interference, significantly improving detection accuracy. Furthermore, the use of the expression "at least one" current characteristic means that in practical implementation, a single or multi-feature fusion strategy can be flexibly selected based on hardware computing power or application scenario, rather than being limited to using all features simultaneously, thus ensuring the broadest applicability of the technical solution.

[0031] In step S300, in response to determining that the current transformer is in a magnetic saturation state, the overcurrent fault memory flag is set. Specifically, when magnetic saturation is confirmed in step S200, it is essentially equivalent to confirming a serious overcurrent fault in the line. However, since magnetic saturation causes distortion of the secondary current waveform and attenuation of the fundamental component, traditional distribution terminal protection devices may not be able to correctly identify the fault, resulting in missed overcurrent signals or switch failure. To avoid this "missed signal" leading to the loss of fault information, this embodiment designs an overcurrent fault memory mechanism. Once magnetic saturation is detected, the overcurrent fault memory flag is immediately set, which is equivalent to establishing a "temporary storage area" for the fault state within the system. This flag is independent of the conventional protection tripping logic and is specifically used to record the occurrence of the magnetic saturation event, ensuring that even if conventional protection fails to operate, the fault trace will not be overwritten or forgotten by subsequent normal operation data.

[0032] In step S400, in response to the detection that the line is in a state of no voltage and no current and the overcurrent fault memory flag is in the set state, the overcurrent signal is re-transmitted and the overcurrent fault memory flag is reset. This step is the key control logic for achieving safe re-transmission. Specifically, the re-transmission of the overcurrent signal must be extremely cautious. If re-transmission is performed blindly before the fault has been cleared, it may lead to the failure of the upstream power supply to reclose or expand the scope of the accident. Therefore, this embodiment sets strict dual triggering conditions: first, the overcurrent fault memory flag must be in the set state, proving that a magnetic saturation fault has indeed occurred; second, the line must be in a state of no voltage and no current, which indicates that the upstream switch has successfully tripped and cleared the fault, and the line has entered a state of power de-isolation. Only when both conditions are met simultaneously does the system determine that the current period is a safe window for re-transmitting the signal, and then executes the re-transmission of the overcurrent signal to provide the master station system with key fault boundary information. After the re-transmission is completed, the memory flag is immediately reset to prevent repeated re-transmission. This timing-based mechanism of "memory + status confirmation" fundamentally eliminates the risk of erroneous resending during the fault's duration, perfectly resolving the technical contradiction in traditional solutions where missed resending and erroneous operation are difficult to balance.

[0033] Through the above process, this embodiment establishes a general methodology for magnetic saturation fault-tolerant handling of current transformers without relying on specific algorithm details. This overarching approach not only covers various existing magnetic saturation detection technologies but also reserves protection space for new detection methods that may emerge in the future, ensuring the legal defensiveness and forward-looking nature of the technical solution.

[0034] Furthermore, such as Figure 4 As shown, a detailed implementation method for magnetic saturation composite detection of a current transformer is presented.

[0035] Specifically, the process of determining whether a current transformer is in a magnetically saturated state, based on at least one of the amplitude characteristics, sampling limit characteristics, and waveform distortion characteristics of at least one phase current signal in a multi-phase current signal, combined with the voltage drop characteristics of the voltage signal, can be achieved by executing high-current detection, analog-to-digital conversion saturation detection, and waveform characteristic detection in parallel. The initial design intention of this parallel processing architecture is that the occurrence of magnetic saturation in current transformers is instantaneous and variable, and single-dimensional detection algorithms may have blind spots or response delays. By placing three detection algorithms based on different physical characteristics into the same time window for independent computation and summarizing the results, if any one of the algorithms meets the judgment condition, the current transformer is determined to be in a magnetically saturated state. This approach can cover various abnormal scenarios from mild to deep saturation, and from symmetrical to asymmetrical faults, to the greatest extent possible, significantly improving the sensitivity and reliability of detection.

[0036] In all three parallel detection algorithms mentioned above, an auxiliary criterion of "the corresponding effective value of the fundamental line voltage being less than a preset voltage threshold" is forcibly introduced. This design is the key difference between this application and existing technologies that rely solely on current characteristics for saturation identification. From the perspective of power system fault mechanisms, when a true short-circuit fault triggers magnetic saturation, the system impedance drops sharply, inevitably accompanied by a significant drop in line voltage. While non-fault interferences such as transformer inrush current, large motor startup, or severe load fluctuations may also cause current waveform distortion or increased amplitude, the system bus voltage usually remains at a normal level or experiences only minor fluctuations. Therefore, using line voltage drop as a necessary prerequisite for all current characteristic criteria can filter out the vast majority of non-fault interference signals at the source, effectively solving the technical problem of easy misjudgment in traditional single-feature detection methods. For example, the preset voltage threshold can be set to 0.8 times the rated line voltage. In practical applications, this threshold can be adjusted according to the grounding method and operating experience of the distribution network system, and is not limited to this specific value.

[0037] The core logic of the high-current detection algorithm is that when the fundamental RMS values ​​of at least two phase current signals in a multi-phase current signal are greater than a preset current initiation threshold, and the corresponding fundamental RMS value of the line voltage is less than a preset voltage threshold, the current transformer is determined to be in a magnetic saturation state. Specifically, this algorithm is mainly for scenarios where the current transformer has not yet entered deep saturation but the overcurrent is severe. The preset current initiation threshold is usually set as a preset initiation multiple of the rated current, such as 5 times the rated current (5In). "At least two phases" is chosen as the judgment object because faults causing CT saturation in distribution networks are mostly phase-to-phase short circuits or three-phase short circuits; single-phase ground fault currents are usually small and generally do not lead to phase CT saturation. By setting a high current initiation threshold and combining it with voltage drop criteria, this algorithm can quickly identify the saturation risk caused by obvious overcurrent faults, serving as a basic protection layer.

[0038] The analog-to-digital converter (CT) saturation detection algorithm aims to capture the "cropping" phenomenon in the secondary current waveform when a current transformer is deeply saturated. The specific criteria are: when at least two phase current signals have a predetermined number of consecutive sampling points with absolute values ​​greater than a predetermined positive threshold within a single power frequency cycle, and a predetermined number of consecutive sampling points with absolute values ​​less than a predetermined negative threshold, while the corresponding line voltage fundamental RMS value is less than a predetermined voltage threshold, the current transformer is determined to be in a magnetic saturation state. In this algorithm, the absolute values ​​of the predetermined positive and negative thresholds are equal and correspond to the analog-to-digital converter sampling values ​​at the current transformer's maximum range; the predetermined number is a predetermined sampling ratio of the total sampling points for a single power frequency cycle. For example, for a system sampling N points per cycle, the predetermined number can be N / 32. When the CT experiences deep saturation, the top of the secondary current waveform is clipped, which is reflected in the digital sampling sequence as multiple consecutive sampling points remaining near the positive or negative limits of the ADC range. This waveform characteristic is a physical fingerprint unique to magnetic saturation. Even if the fundamental effective value is attenuated to below the conventional protection setting due to waveform distortion, the algorithm can still act sensitively, thereby making up for the failure defect of traditional protection based on the fundamental effective value in the deep saturation range.

[0039] The waveform feature detection algorithm focuses on analyzing the distortion characteristics and symmetry of the current waveform. Specific judgment conditions include: when the fundamental effective value of at least two phase current signals is greater than a preset current characteristic threshold, the absolute values ​​of both forward and reverse peak values ​​are greater than a preset peak threshold, the corresponding line voltage fundamental effective value is less than a preset voltage threshold, and the third harmonic content is greater than a preset harmonic threshold, the current transformer is determined to be in a magnetic saturation state. Here, the preset current characteristic threshold is a preset characteristic multiple of the rated current value (e.g., 2In), the preset peak threshold is a preset peak multiple of the preset current characteristic threshold (e.g., 1.414 times), and the preset harmonic threshold is a preset harmonic percentage (e.g., 20%). It is particularly important to note that requiring both forward and reverse peak values ​​to be greater than the preset peak threshold is to characterize the symmetry of the waveform distortion. This is because the magnetic saturation caused by a real short-circuit fault usually exhibits symmetrical saturation in both the positive and negative half-cycles; while certain external interferences or DC bias magnetization may cause unidirectional waveform distortion. By combining the third harmonic content as a saturation-sensitive indicator, the algorithm can provide high-precision recognition capabilities at moderate saturation levels, further enriching the depth of multidimensional feature detection.

[0040] It should be understood that the specific parameter values ​​listed in the above embodiments (such as 5In, N / 32, 20%, 0.8Un, etc.) are only preferred examples adapted to typical distribution network scenarios and are not intended to limit the scope of protection of this application. In actual engineering implementation, technicians can adaptively adjust the above thresholds according to the specific model of the instrument transformer, the system short-circuit capacity, and the level of on-site interference. Furthermore, the parallel execution of the three detection algorithms does not mean that they must be started simultaneously or use the same calculation cycle; it is sufficient that their respective logical operations are completed and results are output within the time window for fault assessment. This flexible and multi-dimensional detection mechanism ensures that the technical solution of this application always possesses excellent robustness and accuracy when facing complex and ever-changing on-site conditions.

[0041] Furthermore, the specific implementation methods of overcurrent fault memory management and safe re-issuance control logic are refined.

[0042] This logic refines the aforementioned steps S300 and S400, aiming to define the technical boundaries of safe retransmission through strict timing constraints, fundamentally resolving the contradiction between overcurrent signal leakage and malfunction in magnetic saturation scenarios. Specifically, the process of retransmitting the overcurrent signal and resetting the overcurrent fault memory flag in response to detecting that the line is in a state of no voltage and no current and that the overcurrent fault memory flag is in a set state includes the following three key control steps.

[0043] The first crucial step is the accurate determination of the no-voltage and no-current state. Real-time monitoring of line voltage and three-phase current is used. When the effective value of the line voltage is less than a preset no-voltage threshold, and the effective values ​​of all three-phase currents are less than the preset no-current threshold, and this state persists for more than a preset confirmation time, the line is determined to be in a no-voltage and no-current state. In this determination logic, the "persistently exceeding the preset confirmation time" is the first line of defense against erroneous re-signaling. At the moment a distribution network fault is cleared, voltage and current signals may exhibit brief false zero values ​​or abnormal fluctuations due to circuit breaker arc extinguishing, electromagnetic transient processes, or interference from the sampling circuit. If judgment is based solely on instantaneous values, this transient process can easily be mistaken for a power outage, leading to erroneous re-signaling before the fault is fully isolated. For example, the preset confirmation time can be set to 0.1 seconds. This duration is sufficient to filter out most transient interference caused by switching operations, while being far less than the timeliness requirements for fault location in feeder automation systems, ensuring a balance between safety and speed in the determination. It should be understood that 0.1 seconds is only an optimal value to adapt to typical distribution network conditions. In practical applications, it can be adjusted according to the on-site interference level and the circuit breaker's operating characteristics.

[0044] The second key element is the dual-identifier management mechanism for overcurrent fault memory. When it is determined that the current transformer is in a magnetically saturated state, both the overall overcurrent fault identifier and the overcurrent fault memory identifier are simultaneously set. When it is determined that the current transformer is not in a magnetically saturated state, the overall overcurrent fault identifier is immediately reset, and the overcurrent fault memory identifier is reset after a preset delay. When the overcurrent fault memory identifier is set and a state of no voltage and no current is detected in the line, the overcurrent signal is immediately re-issued, and the overcurrent fault memory identifier is immediately reset. This design constructs a state machine model that separates "real-time state" from "historical memory." The overall overcurrent fault identifier faithfully reflects the current magnetic saturation detection result and is immediately cleared once the saturation characteristic disappears, ensuring the real-time nature of state perception. The overcurrent fault memory identifier, on the other hand, has "stickiness." Its function is to maintain the fault record even when the magnetic saturation characteristic becomes unstable due to severe waveform distortion or even disappears temporarily, preventing the loss of fault information due to the momentary failure of the detection algorithm. More importantly, the reset strategy of this memory identifier employs conditional branching logic: if the fault disappears naturally (e.g., load recovery) and no retransmission is triggered, it is automatically cleared after a preset delay (e.g., 1 second), completing a full fault recording cycle; if a retransmission is triggered due to the detection of no voltage or no current, it is immediately cleared during the retransmission. This "immediate reset" mechanism ensures that the same fault event is only retransmitted once, completely eliminating the problem of repeated retransmissions caused by signal jitter or repeated states, and guaranteeing the uniqueness and accuracy of the information received by the master station system.

[0045] The third key aspect is the reliable output and maintenance of the retransmission signal. Immediately executing the retransmission of the overcurrent signal specifically includes: setting the overcurrent retransmission flag, outputting a hard contact closure signal, and sending an event sequence record signal to the master station system; the overcurrent retransmission flag automatically resets after a preset hold time to restore its initial state; wherein, the preset hold time is greater than the hard remote signaling detection debouncing time of the distribution terminal. In engineering practice, to suppress contact jitter and electromagnetic interference, distribution terminals typically incorporate software or hardware debouncing filters in the hard remote signaling acquisition circuit, with debouncing times generally between 20 and 100 milliseconds. If the pulse width of the retransmission signal is less than this debouncing time, the signal will be treated as interference noise and filtered out by the terminal, leading to retransmission failure. Therefore, this embodiment explicitly requires that the hold time of the retransmission signal must be greater than the terminal's debouncing time. For example, the preset hold time can be set to 0.5 seconds, which not only far exceeds the conventional debouncing time but also provides sufficient margin for communication delays and master station polling cycles. Meanwhile, a dual output mode of "hard contact + Sequence of Events (SOE)" is adopted, balancing compatibility and accuracy: the hard contact signal can be directly connected to the backup remote signaling port of the existing power distribution terminal, achieving physical-level signal transmission without modifying the terminal hardware; the SOE signal is uploaded through the communication protocol, carrying a timestamp accurate to the millisecond level, providing crucial data support for fault timing analysis and precise location of the main station system. This hardware and software collaborative output strategy ensures that the retransmitted signal can be reliably acquired and identified under various equipment conditions and communication environments.

[0046] After the overcurrent signal is retransmitted, the process includes terminal-side signal processing and uploading steps, which can be performed using any of the following methods. This design aims to solve the signal access problem in existing distribution network automation systems caused by equipment heterogeneity and differences in master station strategies. By providing multiple compatibility modes, it ensures that the magnetic saturation fault tolerance function can be seamlessly integrated into the existing feeder automation system without requiring high-risk, high-cost modifications to the master station's core fault location logic.

[0047] Method 1 involves performing an OR operation between the original overcurrent signal and the overcurrent compensation signal within the distribution terminal to generate a fused overcurrent signal, which is then uploaded to the master station system. Specifically, this method is primarily suitable for scenarios where the master station system has a fixed point table, does not support online expansion of remote signaling points, or where maintenance management regulations strictly limit modifications to the master station database. In implementation, the distribution terminal's software program allocates a logic operation unit in memory to perform a real-time logical OR operation between the remote signaling status bit originally used to represent conventional overcurrent protection and the overcurrent compensation flag status bit generated in the aforementioned embodiments of this application. As long as either bit is true (i.e., set), the generated fused overcurrent signal is true and is uploaded via existing communication protocols as the standard for overcurrent remote signaling. The biggest advantage of this processing method is its complete transparency to the master station system. From the master station's perspective, it still receives the original overcurrent signal point; its data model, alarm triggering mechanism, and logical weights involved in fault location remain unchanged. This means that even on the oldest and most closed master station systems, only a single software upgrade or parameter configuration of the power distribution terminal is needed to immediately obtain CT magnetic saturation fault tolerance capability, greatly reducing the threshold for engineering implementation and acceptance risks. At the same time, since the timing of the fused signal is consistent with that of the conventional overcurrent signal, it also avoids logical misjudgments that may be caused by timestamp alignment issues from multiple signal sources.

[0048] Method two involves adding a magnetic saturation compensation overcurrent remote signaling point to the existing remote signaling points in the distribution terminal. The master station system then performs equivalent processing between the magnetic saturation compensation overcurrent remote signaling point and the original overcurrent signal. Specifically, this method is suitable for scenarios where the master station system has flexible point table management capabilities, and the maintenance department wants to independently statistically analyze magnetic saturation faults. At the hardware level, distribution terminals typically have several reserved spare hard remote signaling input ports. The overcurrent compensation flag output by the CT magnetic saturation detection module can be directly connected to these spare ports without modifying the terminal's internal circuitry. At the software and master station configuration level, the remote signaling address corresponding to the spare port needs to be enabled in the distribution terminal's point table, and the corresponding remote signaling definition needs to be added to the master station system. Crucially, although a new independent physical point is added, the master station's feeder automation fault location algorithm will configure this new point to have the same topological association attributes and logical priority as the original overcurrent signal, thus achieving equivalent processing. When the master station receives the action signal from the newly added point, it will treat it as an overcurrent fault in the switch, thus correctly participating in the fault range assessment. Compared to Method 1, Method 2 retains the original granularity of the information. Maintenance personnel can clearly distinguish whether an overcurrent event was triggered by conventional protection or by the CT magnetic saturation fault-tolerant mechanism by checking the status of this independent point. This improved observability is of significant data value for post-fault review, CT saturation frequency statistics, and equipment health assessment. Simultaneously, because the two signals are physically independent, the risk of coupling interference from software logic operations is completely eliminated, improving the overall reliability of the system.

[0049] It should be understood that although the two methods differ in implementation path and information presentation, their core technology is essentially the same: both achieve decoupling between the detection module and the core logic of the main station. Regardless of the method used, there is no need to modify the core algorithm code in the main station system regarding network topology, fault location, and isolation strategies. This is crucial for ensuring the safe and stable operation of existing distribution network automation systems. In practical engineering applications, technicians can flexibly choose the most suitable signal access mode based on the hardware margins of the field distribution terminals, the openness of the main station system, and the specific needs of operation and maintenance management. For example, within the same power supply area, method two can be used for critical nodes to obtain richer diagnostic information, while method one can be used for general branch nodes to achieve rapid batch coverage. This high degree of engineering adaptability makes the technical solution of this application not only theoretically advanced but also practically feasible for large-scale promotion and application.

[0050] like Figure 2As shown, this embodiment provides a magnetic saturation fault-tolerant processing system for current transformers. This system aims to achieve magnetic saturation identification and signal retransmission functions without replacing primary equipment in the field through a modular architecture design. Specifically, the system includes a current transformer magnetic saturation detection module, a power distribution terminal, and a master station system.

[0051] The current transformer magnetic saturation detection module is configured to acquire multi-phase current and voltage signals. Based on at least one of the amplitude characteristics, sampling limit characteristics, and waveform distortion characteristics of at least one phase current signal, combined with the voltage drop characteristics of the voltage signal, it determines whether the current transformer is in a magnetic saturation state. This module, as the core of the system's sensing capabilities, independently undertakes the complex tasks of signal analysis and saturation assessment. Physically, the current transformer magnetic saturation detection module shares the voltage transformer and secondary output signals of the current transformer with the distribution terminal. Specifically, this "sharing" mechanism is typically achieved by parallel wiring on the secondary terminal blocks within the ring main unit or switchgear. This involves extending an additional set of cables from the existing CT / PT secondary output terminals to the detection module, while the existing cables connected to the distribution terminal remain unchanged. The core value of this architecture lies in completely avoiding the engineering challenges of replacing the primary current transformer. Due to the extremely compact internal space of existing distribution network equipment, larger, high-precision CTs are often unsuitable, and replacing a CT requires power outages and dismantling of the primary busbar, resulting in extremely high construction risks and costs. By sharing the secondary side signal, this application only requires the addition of a small detection module to complete the functional upgrade, greatly reducing the threshold for modification. It should be understood that, although... Figure 2 While the example demonstrates an external, independent module, in other embodiments, as long as the functional logic of signal acquisition and processing is satisfied, the specific physical form of the detection module can be an independent box-type device, a board plug-in, or a sub-unit integrated into other secondary equipment, all of which fall within the protection scope of this application.

[0052] The distribution terminal is configured to set the overcurrent fault memory flag in response to determining that the current transformer is in a magnetic saturation state; and to execute a supplementary overcurrent signal output and reset the overcurrent fault memory flag in response to detecting that the line is in a state of no voltage and no current and the overcurrent fault memory flag is set. In this embodiment, the interaction between the distribution terminal and the current transformer magnetic saturation detection module is diverse. As a preferred implementation, the two can be connected via hard contacts, that is, when the detection module determines that a supplementary signal needs to be sent, it closes its internal relay contacts, which are directly connected to the backup remote signaling input port of the distribution terminal. This method has strong compatibility and is applicable to almost all models of existing distribution terminals, and does not depend on the adaptation of communication protocols. As another implementation, the two can also be connected via a communication interface (such as RS485, CAN bus, or UART). The detection module packages information such as saturation state and fault records into a message and sends it to the distribution terminal, which then parses it and triggers its internal logic. This method has a large information carrying capacity and is convenient for transmitting richer diagnostic data. Regardless of the interaction method used, the power distribution terminal acts as a signal relay and execution node, converting the judgment results of the front-end detection module into an overcurrent signal that conforms to the feeder automation standard.

[0053] The master station system is configured to receive overcurrent information uploaded by the distribution terminals and determine the fault range. Specifically, the distribution terminals upload supplementary overcurrent signals to the master station system via power standard communication protocols (such as IEC 60870-5-101 / 104). Since the supplementary signals are semantically equivalent to regular overcurrent signals, or have been mapped to equivalent fault indications, the master station system can directly use this information to correctly determine the fault range without modifying its core fault location algorithm or topology model. This "transparent" design to the master station avoids the systemic risks associated with large-scale modifications to the master station software, further improving the engineering feasibility of the solution.

[0054] In addition, such as Figure 3As shown, for intelligent distribution terminals with software upgrade capabilities, this application also provides a software-integrated system architecture variant. In this variant, the current transformer magnetic saturation detection module no longer exists as independent hardware, but is embedded in the distribution terminal's internal program as a software functional module. At this time, the characteristic of "sharing the secondary output signals of the voltage transformer and current transformer of the primary switch" manifests physically as the distribution terminal's own sampling circuit directly acquiring CT / PT signals, and logically as the magnetic saturation detection software module sharing the same sampling data buffer with the original protection and control program. Correspondingly, the interaction between the detection module and the distribution terminal changes from external hard contacts or communication interfaces to internal inter-process communication or shared memory variable transfer. This software integration method eliminates the hardware cost and installation wiring work of external detection modules, making it particularly suitable for new projects or batch software upgrade scenarios. It should be understood that regardless of... Figure 2 The external hardware mode shown is still Figure 3 The software integration mode shown maintains the same core signal processing logic and control strategy, differing only in the physical carrier and data path. The two complement each other and together constitute the complete system protection system of this application.

[0055] Through the above system architecture, this embodiment achieves seamless integration of magnetic saturation detection functionality with the existing distribution network automation system. The shared secondary signal design overcomes the physical bottleneck of hardware upgrades, the flexible interaction method adapts to different generations of terminal equipment, and the zero-intrusion into the master station logic ensures system-level security and stability. This multi-layered, highly compatible architecture design ensures the technical solution has broad applicability and promotional value in practical engineering.

[0056] This application also provides a computer-readable storage medium storing a computer program. When executed by a processor, the computer program implements the aforementioned current transformer magnetic saturation fault-tolerant processing method. Specifically, this computer-readable storage medium is the physical carrier for the software implementation of the technical solution of this application, enabling the aforementioned complex magnetic saturation detection and safety re-issuance logic to be distributed, installed, and upgraded as a software product. In practical applications, the storage medium can be non-volatile, such as read-only memory, electrically erasable programmable read-only memory, flash memory, disk storage devices, optical disk storage devices, etc.; or it can be volatile, such as random access memory, as long as it can retain program instructions for a certain period of time for the processor to read and execute. When the processor loads and runs the aforementioned computer program from the storage medium, general-purpose computing hardware is configured as a functional module specifically for solving the CT magnetic saturation problem, automatically executing a series of steps including multi-dimensional feature composite judgment, overcurrent fault memory management, and no-voltage and no-current state triggered re-issuance. This software-based implementation greatly enhances the flexibility of the technical solution. For existing power distribution terminals, maintenance personnel only need to update the program code in the storage medium through on-site or remote upgrades to give the equipment magnetic saturation fault tolerance, without having to replace the hardware board, which significantly reduces the maintenance cost throughout the entire life cycle.

[0057] Furthermore, this application also provides a power distribution terminal device, including a processor and a memory. The memory stores a computer program, wherein the processor executes the computer program to implement the current transformer magnetic saturation fault-tolerant processing method described above. Specifically, this power distribution terminal device is the physical implementation of the technical solution of this application in a power distribution network automation system. The processor can be a central processing unit (CPU), digital signal processor (DSP), microcontroller (MCU), or field-programmable gate array (FPGA) chip with data processing capabilities; the memory corresponds to the aforementioned computer-readable storage medium and is used to persistently or temporarily store the instruction set and operating data for implementing the method of this application. In terms of hardware architecture, the processor is connected to the memory, sampling circuit, communication interface, and hard contact output circuit through an internal bus to form a complete embedded control system. When the device is running, the processor calls the program in the memory in real time to perform parallel analysis of the current and voltage data obtained by the sampling circuit, and drives the hard contact output circuit to close or sends an SOE signal through the communication interface when preset conditions are met. It should be understood that the specific product form of this power distribution terminal equipment is not limited to traditional stand-alone DTU cabinets. It can also be a compact intelligent component integrated inside a ring main unit, a control unit in a primary and secondary integrated switch body, or even a new type of power Internet of Things terminal such as an edge computing gateway. Regardless of the physical packaging form, as long as it contains a processor and memory combination that executes the method described in this application, it falls within the protection scope of this application. By embedding the core algorithm inside the terminal equipment, this application ensures the real-time performance and reliability of magnetic saturation fault-tolerant processing, enabling it to complete fault assessment and signal retransmission within a millisecond timescale, effectively supporting the performance requirements of centralized feeder automation systems for rapid fault isolation.

[0058] To more clearly illustrate the application value of the technical solution in practical engineering, this embodiment provides a full-process application example of magnetic saturation fault-tolerant handling of current transformers in a centralized feeder automation scenario of a distribution network. This example substitutes the abstract method steps described in the previous embodiments into a specific fault handling sequence, verifying its effectiveness in resolving the contradiction between signal leakage and malfunction under extreme operating conditions.

[0059] The specific application scenario is as follows: A 10kV distribution network line adopts a centralized feeder automation mode. The ring main unit is equipped with a phase current transformer with a transformation ratio of 600 / 5A and an accuracy class of 5P10. Its theoretical unsaturation upper limit is approximately 6kA. The system rated frequency is 50Hz, and the sampling rate is 128 points per cycle. At a certain moment, a two-phase metallic short-circuit fault occurs on this line, and the short-circuit current at the fault point reaches as high as 20kA, far exceeding the linear operating range of the current transformer.

[0060] At the instant the fault occurs, the steps of acquiring multiphase current and voltage signals are executed. Specifically, due to the short-circuit current reaching 20kA, the current transformer core rapidly enters a state of deep magnetic saturation, resulting in severe distortion of the secondary side output waveform, exhibiting obvious clipping characteristics, and the fundamental component attenuates significantly to about twice the rated value, accompanied by the generation of a large number of odd harmonics. Simultaneously, the fault causes a sharp drop in line impedance, with the corresponding effective value of the line voltage fundamental wave falling from the rated value to below 0.2 times the rated value. Data acquisition at this stage provides the initial basis for subsequent accurate analysis.

[0061] Next, the system determines whether the current transformer is in a magnetically saturated state based on at least one of the amplitude characteristics, sampling limit characteristics, and waveform distortion characteristics of at least one phase current signal in the multi-phase current signal, combined with the voltage drop characteristics of the voltage signal. In this scenario, the three parallel detection algorithms mentioned above play a crucial complementary role. Although the high-current detection algorithm may not reach the preset high threshold (e.g., 5In) due to the attenuation of the fundamental effective value, the analog-to-digital conversion saturation detection algorithm keenly captures the clipping characteristic of multiple consecutive sampling points maintaining positive and negative limit values ​​within a single power frequency cycle; at the same time, the waveform feature detection algorithm also identifies the third harmonic content exceeding 20% ​​and the abnormal symmetry of positive and negative peaks. More importantly, all the above-mentioned current characteristic anomalies are accompanied by the necessary condition that the line voltage fundamental effective value is less than the preset voltage threshold (e.g., 0.8Un), thus completely eliminating the possibility of non-fault interference such as transformer inrush current. Finally, the system determines that the current transformer is in a magnetically saturated state through "OR" logic synthesis, confirming the occurrence of a severe overcurrent fault.

[0062] In response to the determination that the current transformer is in a magnetic saturation state, the system immediately sets the overcurrent fault memory flag. Specifically, although the conventional overcurrent protection of the distribution terminal may fail to activate at this time because the fundamental wave measurement value is lower than the set value, or even if it activates, the output relay may be unreliable due to waveform distortion, the fault tolerance mechanism of this application has established an independent fault record internally. This memory flag acts like a black box, faithfully recording the occurrence of the magnetic saturation event, ensuring that fault information is not lost due to distortion in front-end perception. In contrast, in traditional technical solutions, this stage often manifests as the protection device failing to operate or the alarm signal being missing, causing the master station system to be unable to perceive the fault state of this node, thus resulting in incorrect fault range location.

[0063] Subsequently, after the fault current persisted for tens of milliseconds, the protection device of the outgoing line switch of the upstream substation correctly operated and tripped to clear the fault, and the line entered a de-energized state. At this time, the system responded by detecting that the line was in a state of no voltage and no current and that the overcurrent fault memory flag was in the set state, executing the re-transmission of the overcurrent signal and resetting the overcurrent fault memory flag. Specifically, after the upstream switch tripped, the system monitored in real time that the effective value of the line voltage was lower than 0.3Un and the effective values ​​of the three-phase currents were all lower than 0.03In, and this state lasted for more than the preset confirmation time of 0.1 seconds, thus confirming that the fault had been isolated and was not a transient interference. Within this safety window, the system immediately closed the hard contact output circuit and sent an SOE signal with a precise time stamp to the master station, while automatically resetting the re-transmission flag after 0.5 seconds. This timing control ensured that the re-transmission signal was only issued after the fault was cleared, which not only avoided the risk of reclosing failure caused by erroneous re-transmission during the fault period, but also successfully filled the signal gap caused by CT saturation.

[0064] Ultimately, after receiving the overcurrent signal reissued by the ring main unit, the distribution network FA master station, combined with the tripping information of the substation outgoing switches and remote signaling data from other nodes, accurately determines that the faulty section is downstream of the ring main unit according to the established topology logic, and remotely controls the relevant tie switches to restore power supply to the non-faulty area. As can be seen from the above full-process application example, the technical solution of this application, even when facing extreme short-circuit faults far exceeding the CT's tolerance, can still ensure the correct decision-making of the feeder automation system through multi-dimensional feature composite judgment and a safe reissue mechanism. This robustness and reliability demonstrated in real fault scenarios is a direct manifestation of the substantial technological advancement and distinguishes this application from existing technologies. It should be understood that the above scenario parameters are only illustrative examples. In actual applications, parameters such as short-circuit current magnitude, CT ratio, and protection action time may differ, but as long as the core processing logic described in this application is followed, the expected fault-tolerant effect can be achieved.

[0065] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for handling magnetic saturation fault tolerance in a current transformer, characterized in that, include: Acquire multiphase current and voltage signals; Based on at least one of the amplitude characteristics, sampling limit characteristics, and waveform distortion characteristics of at least one phase current signal in the multiphase current signal, combined with the voltage drop characteristics of the voltage signal, it is determined whether the current transformer is in a magnetic saturation state. In response to determining that the current transformer is in the magnetic saturation state, the overcurrent fault memory flag is set; In response to the detection that the line is in a state of no voltage and no current and the overcurrent fault memory flag is in a set state, the overcurrent signal is retransmitted and the overcurrent fault memory flag is reset.

2. The method according to claim 1, characterized in that, The determination of whether the current transformer is in a magnetic saturation state based on at least one of the amplitude characteristics, sampling limit characteristics, and waveform distortion characteristics of at least one phase current signal in the multiphase current signal, combined with the voltage drop characteristics of the voltage signal, includes: Parallel execution of high current detection, analog-to-digital conversion saturation detection, and waveform feature detection; In the high current detection, when the fundamental effective value of at least two phase current signals in the multiphase current signal is greater than the preset current start threshold, and the corresponding line voltage fundamental effective value is less than the preset voltage threshold, the current transformer is determined to be in the magnetic saturation state. In the analog-to-digital conversion saturation detection, when the absolute value of a consecutive preset number of sampling points of the at least two-phase current signals is greater than a preset positive limit threshold within a single power frequency cycle, and there is a consecutive preset number of sampling points with an absolute value less than a preset negative limit threshold, and the corresponding line voltage fundamental effective value is less than the preset voltage threshold, the current transformer is determined to be in the magnetic saturation state. In the waveform feature detection, when the fundamental effective value of the at least two phase current signals is greater than the preset current feature threshold, the absolute values ​​of the forward and reverse peaks are both greater than the preset peak threshold, the corresponding line voltage fundamental effective value is less than the preset voltage threshold, and the third harmonic content is greater than the preset harmonic threshold, the current transformer is determined to be in the magnetic saturation state. If any one of the high current detection, the analog-to-digital conversion saturation detection, and the waveform feature detection meets the condition, it is determined that the current transformer is in the magnetic saturation state.

3. The method according to claim 2, characterized in that, The determination conditions for the high current detection and the analog-to-digital conversion saturation detection include: In the high current detection, the preset current start threshold is a preset start multiple of the current rating; In the analog-to-digital conversion saturation detection, the absolute values ​​of the preset positive limit threshold and the preset negative limit threshold are equal, and they correspond to the analog-to-digital conversion sampling value of the current transformer at its maximum range; the preset quantity is the preset sampling ratio of the total sampling points of a single power frequency cycle; When the absolute value of the analog-to-digital conversion sampled value of the at least two phase current signals is greater than the preset positive limit threshold and the absolute value of the preset number of sampled points is less than the preset negative limit threshold within the single power frequency cycle, it is determined that the conditions for analog-to-digital conversion saturation detection are met.

4. The method according to claim 2, characterized in that, The determination criteria for waveform feature detection include: The preset current characteristic threshold is a preset characteristic multiple of the current rated value; The preset peak threshold is a preset peak multiple of the preset current characteristic threshold; The preset harmonic threshold is a preset harmonic percentage; In the waveform feature detection, it is required that the absolute values ​​of the positive peak and the negative peak of the at least two phase current signals are both greater than the preset peak threshold to characterize the symmetry of waveform distortion, and the percentage of the third harmonic content of the at least two phase current signals relative to the fundamental wave is greater than the preset harmonic threshold.

5. The method according to claim 1, characterized in that, The step of responding to the detection that the line is in a state of no voltage and no current and the overcurrent fault memory flag is in a set state, performing a retransmission of the overcurrent signal and resetting the overcurrent fault memory flag, includes: The line voltage and three-phase current of the line are monitored in real time. When the effective value of the line voltage is less than the preset no-voltage threshold and the effective value of the three-phase current is less than the preset no-current threshold, and this state continues for more than the preset confirmation time, the line is determined to be in the state of no voltage and no current. When it is determined that the current transformer is in the magnetic saturation state, the overcurrent fault general flag and the overcurrent fault memory flag are set; When it is determined that the current transformer is not in the magnetic saturation state, the overcurrent fault general flag is immediately reset, and the overcurrent fault memory flag is reset after a preset delay. When the overcurrent fault memory flag is set and the line is detected to be in the state of no voltage and no current, the overcurrent signal is immediately re-issued and the overcurrent fault memory flag is immediately reset.

6. The method according to claim 5, characterized in that, The immediate execution of the overcurrent signal retransmission output includes: Set the overcurrent compensation flag, output a hard contact closure signal, and send an event sequence record signal to the master station system; The overcurrent compensation flag is automatically reset after a preset holding time to restore its initial state; The preset holding time is longer than the hard remote signaling detection debounce time of the power distribution terminal.

7. The method according to claim 1, characterized in that, After the overcurrent signal is retransmitted, the process further includes a terminal-side signal processing and uploading step, which can be performed in any of the following ways: Method 1: Perform an OR operation between the original overcurrent signal and the overcurrent compensation signal inside the power distribution terminal to generate a fused overcurrent signal and upload it to the main station system; Method 2: Based on the existing remote signaling points of the power distribution terminal, a new magnetic saturation compensation overcurrent remote signaling point is added, and the master station system performs equivalent processing on the magnetic saturation compensation overcurrent remote signaling point and the original overcurrent signal.

8. A magnetic saturation fault-tolerant processing system for a current transformer, characterized in that, include: The current transformer magnetic saturation detection module is configured to acquire multiphase current signals and voltage signals, and determine whether the current transformer is in a magnetic saturation state based on at least one of the amplitude characteristics, sampling limit characteristics and waveform distortion characteristics of at least one phase current signal in the multiphase current signals, combined with the voltage drop characteristics of the voltage signals. The power distribution terminal is configured to set an overcurrent fault memory flag in response to determining that the current transformer is in the magnetic saturation state. In response to detecting that the line is in a state of no voltage and no current and the overcurrent fault memory flag is in a set state, the overcurrent signal is retransmitted and the overcurrent fault memory flag is reset. The main station system is configured to receive overcurrent information uploaded by the power distribution terminal and determine the fault range. The current transformer magnetic saturation detection module shares the secondary output signals of the voltage transformer and current transformer of the primary switch with the power distribution terminal.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the current transformer magnetic saturation fault-tolerant processing method as described in any one of claims 1 to 7.

10. A power distribution terminal device, characterized in that, include: processor; Memory, used to store computer programs; Wherein, when the processor executes the computer program, it implements the current transformer magnetic saturation fault-tolerant processing method as described in any one of claims 1 to 7.

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