A detection method and system for adjacent two-phase mutual exchange of a three-phase metering box

Abstract

The application relates to the technical field of power system electric energy metering anomaly detection, and discloses a detection method and a detection system for adjacent two-phase mutual exchange through cores of a three-phase metering box. The detection system is executed, and is used for the three-phase metering box which is internally provided with three fixedly arranged current transformers. After correct external terminal wiring and power-off conduction detection pass, two adjacent phases are selected as target phase pairs, and the remaining one phase is taken as a non-target phase. Opposite directions and equal amplitudes of test excitation are applied to the two-phase primary conductors in the target phase pair, the secondary circuit responses of two target current transformers and a non-target current transformer are synchronously collected, and when the non-target current transformer meets a preset residual response limit condition, whether the mutual exchange through cores occurs is determined according to the matching result of the target current transformer response and a preset reverse response signature. The application can detect the adjacent two-phase mutual exchange through cores under the conditions of power-off and without disassembling the box, and improves the pertinence and accuracy of detection.

Description

Technical Field

[0001] This application relates to the technical field of power system energy metering anomaly detection, and in particular to a detection method and system for detecting adjacent double-phase cross-connection of a three-phase metering box. Background Technology

[0002] Three-phase metering boxes are widely used in power system energy metering scenarios to collect and measure the energy parameters of three-phase lines. For three-phase metering boxes that use current transformers for current sampling, the box body generally contains current transformers corresponding to the primary conductors of each phase. Current detection is achieved by having the primary conductors pass through the corresponding current transformers. Since three-phase metering boxes usually have a fixed box type, the installation position and arrangement of the three-phase primary conductors and current transformers are usually relatively fixed.

[0003] During actual assembly, maintenance, or replacement, abnormalities may occur in the conductor-to-current transformer connection, such as the conductors of two adjacent phases being interchanged between two adjacent current transformers. This type of abnormality differs from external terminal wiring errors or obvious open-circuit faults because it can still exist even when the external terminal wiring is correct and continuity tests pass, making it highly concealed. If this type of abnormality is not detected in time, it may lead to inaccurate subsequent metering results, affecting the accuracy of electricity metering.

[0004] In existing technologies, the verification of the internal wiring status or current transformer correspondence of three-phase metering boxes typically involves opening the box for inspection or making judgments based on electrical testing results. The former relies on on-site operating conditions and is not conducive to rapid verification without opening the box; while the latter can be implemented without opening the box, it still lacks an effective means of identifying cases where the external wiring is normal and the continuity test passes, but there are still abnormalities in the internal current transformer correspondence, particularly for cases where adjacent two-phase current transformers are swapped.

[0005] Therefore, how to accurately detect whether adjacent two-phase circuits inside a fixed-box three-phase metering box have interchanged through-holes, without opening the box, provided that the external terminal wiring is correct and the continuity test is passed, has become an urgent technical problem to be solved. Summary of the Invention

[0006] (I) The technical problem to be solved by the present invention is: under the premise that the external terminal wiring of the three-phase metering box is correct and the power failure continuity test is passed, how to detect whether the primary conductors of two adjacent phases inside the fixed box-type three-phase metering box have been interchanged between two adjacent current transformers without disassembling the box.

[0007] (II) Technical Solution

[0008] The technical problem to be solved by this invention is: in a three-phase metering box with a fixed box type and fixed CT arrangement, under the condition of correct external terminal wiring and passing continuity test, how to detect whether the primary conductors of two adjacent phases have been interchanged between two adjacent current transformers under the condition of power failure and without disassembling the box.

[0009] To address the aforementioned technical problems, this application provides a detection method for adjacent double-phase current transformers in a three-phase metering box. The method is executed by a detection system, which detects the three-phase metering box, which is a fixed box type containing three current transformers arranged in a fixed configuration. After confirming that the external terminals of the three-phase metering box are correctly wired and that the power-off continuity test has passed, the specific steps of the detection method include:

[0010] S1. Without unpacking, select two adjacent phases to be checked and establish them as target phase pairs. The target phase pairs include the primary conductor of the first phase and the corresponding first target current transformer, the primary conductor of the second phase and the corresponding second target current transformer, and establish the remaining primary conductor of the first phase and the corresponding current transformer as non-target phase primary conductors and non-target current transformers respectively.

[0011] S2. Apply a first-direction test excitation to the first-phase primary conductor, and simultaneously apply a second-direction test excitation to the second-phase primary conductor that is opposite to the first-direction test excitation and has the same amplitude, and keep the non-target phase primary conductor without test excitation input during the detection cycle;

[0012] S3. Synchronously acquire the secondary circuit responses of the first target current transformer and the second target current transformer, as well as the secondary circuit responses of the non-target current transformer;

[0013] S4. When the secondary circuit response of the non-target current transformer meets the preset residual response restriction condition, the target phase pair is determined to have undergone a crossover based on the matching result of the secondary circuit responses of the first target current transformer and the second target current transformer with the preset reverse response signature.

[0014] First, assuming the external terminal wiring is correct and the power-off continuity test passes, the objects to be checked are limited to two adjacent phase primary conductors and their corresponding two target current transformers. The remaining corresponding current transformer is considered a non-target current transformer, thus focusing the detection range on the specific anomaly of adjacent double-phase cross-connection. Subsequently, by simultaneously applying test excitations of opposite directions and equal amplitudes to the two phase primary conductors in the target phase pair, and keeping the non-target phase primary conductor without test excitation input during the detection cycle, the target phase pair forms a distinguishable pairwise response basis during the detection process.

[0015] Based on this, the secondary circuit responses of the first target current transformer, the second target current transformer, and the non-target current transformer are simultaneously collected. When the secondary circuit response of the non-target current transformer meets the preset residual response limit condition, the matching results of the secondary circuit responses of the first and second target current transformers with the preset reverse response signature are combined to determine whether the target phase pairs have undergone cross-connection. Therefore, under the condition of power outage and without disassembling the box, it is possible to detect whether the primary conductors of adjacent two phases inside a fixed box-type three-phase metering box have undergone cross-connection between adjacent two current transformers. This is beneficial for identifying hidden faults where the external wiring is normal but the internal cross-connection correspondence is abnormal, and improves the pertinence, accuracy, and reliability of adjacent pair cross-connection detection.

[0016] Furthermore, in step S4, the preset residual response limitation condition includes a residual response threshold set for the secondary circuit response of the non-target current transformer. The residual response threshold is preset or calibrated based on the relative position parameters of the target phase and the primary conductor of the non-target phase in a fixed-box three-phase metering box.

[0017] The residual response threshold corresponding to the secondary circuit response of the non-target current transformer is pre-set or calibrated by combining it with the relative position parameters between the target phase and the primary conductors of the non-target phase under a fixed box configuration. This ensures that the residual response constraint is no longer a general constant detached from the actual spatial structure of the metering box, but rather adapts to the relative spatial relationship between the conductors and current transformers within the fixed box. This helps reduce the impact of non-target phase coupling residues caused by different fixed box configurations or relative positional relationships on the detection results, improves the ability to distinguish non-target interference, and thus enhances the accuracy and stability of adjacent double-phase cross-connection determination.

[0018] Furthermore, the relative position parameters include the center distance between the two primary conductors of the target phase pair, and the geometric distance from the non-target phase primary conductor to the target phase pair;

[0019] The residual response threshold is configured with both absolute threshold conditions and relative threshold conditions. The relative threshold condition is configured such that the secondary circuit response amplitude of the non-target current transformer is less than a preset proportion of the smaller of the secondary circuit response amplitudes of the first target current transformer and the second target current transformer.

[0020] This invention further refines the criteria for determining the degree of coupling between non-target phases, and through a more robust threshold constraint method, the identification of residual interference no longer relies on a single, coarse judgment standard. This helps to reduce the impact of spatial coupling changes on the detection results and further improves the accuracy and adaptability of the detection of adjacent double-crossing.

[0021] Further, in step S4, based on the matching result of the secondary circuit responses of the first target current transformer and the second target current transformer with the preset reverse response signature, it is determined whether the target phase pair has undergone a crossover. Specifically:

[0022] A first polarity response relationship between the fixed channel of the first target current transformer and the first direction test excitation, and a second polarity response relationship between the fixed channel of the second target current transformer and the second direction test excitation are established in advance.

[0023] When the actual response polarity extracted from the secondary circuit response of the first target current transformer and the second target current transformer, and its affiliation on the fixed channel of the first target current transformer and the second target current transformer, is reversed relative to the first polarity response relationship and the second polarity response relationship, it is determined that the target phase pair has undergone a cross-connection.

[0024] By establishing the recognition of interchangeable cores on the basis of response assignment changes on fixed channels, the originally abstract response comparison is transformed into a judgment criterion corresponding to physical channels, thereby reducing the ambiguity when judging solely based on response strength or general polarity relationships, and improving the pertinence and rigidity of interchangeable core recognition.

[0025] Furthermore, the actual response polarity extracted from the secondary circuit responses of the first target current transformer and the second target current transformer is specifically determined by extracting the signed response quantity of the secondary circuit responses of the first target current transformer and the second target current transformer within a preset detection window.

[0026] The signed response quantity is composed of at least one of the integral value of the response waveform within the preset detection window, the phase sign quantity, or the polarity sign quantity.

[0027] The preset detection window is located within the time overlap interval between the first direction test stimulus and the second direction test stimulus, and excludes the initial transient response interval and the removal transient response interval of the test stimulus.

[0028] The actual response polarity corresponding to the fixed channel assignment is further converted into a measurable, extractable, and reproducible physical judgment quantity, and the interference of transient fluctuations in the initial and removal stages of test excitation on the response polarity extraction results is reduced, thereby improving the stability of the fixed channel assignment reversal criterion and thus improving the accuracy and reliability of adjacent double mutual interchange detection.

[0029] Furthermore, it also includes a reverse verification step, the specific steps of which include:

[0030] After completing steps S2 to S4 and obtaining the first determination result, the directions of the test excitation applied to the first phase primary conductor and the second phase primary conductor are simultaneously reversed to execute the second detection cycle.

[0031] During the second detection cycle, the secondary circuit responses of the first target current transformer, the second target current transformer, and the non-target current transformer are resynchronized and collected. The second determination result is obtained again based on the matching result of the residual response constraint and the reverse response signature.

[0032] The first determination result is compared with the second determination result for consistency, and the comparison result is used as the basis for the final detection conclusion.

[0033] By reversing the overall test excitation of the two paths after the first test and performing a second test, the symmetrical change in the excitation direction between the two tests is used to verify the risk of misjudgment caused by differences in test fixture contact, excitation imbalance or accidental coupling disturbance in a single test, thereby improving the stability and reliability of the interchangeable core judgment result.

[0034] Furthermore, the first determination result and the second determination result are compared for consistency, and the comparison result is used as the basis for the final detection conclusion, specifically including:

[0035] When the first determination result is consistent with the second determination result, based on the consistent determination result, a definite conclusion is output that adjacent pairs exchange through the center or the center is correct.

[0036] When the first determination result is inconsistent with the second determination result, the detection conclusion of abnormal coupling to be reviewed is output.

[0037] By setting different output rules for consistent and inconsistent cases, it is beneficial to output a clear conclusion when the two detection results are consistent, and to avoid forcibly giving a judgment of interchangeable cores or correct cores when the two detection results are inconsistent. This reduces the misleading influence of accidental disturbances, contact differences or local abnormal coupling on the final detection conclusion, and improves the reliability and engineering applicability of the detection results of adjacent double interchangeable cores.

[0038] Furthermore, the first direction test excitation and the second direction test excitation applied in step S2 are generated from the same reference test signal after phase inversion and amplitude balancing, so that the start-up time of the two test excitations applied to the first phase primary conductor and the second phase primary conductor are synchronized, the amplitudes are equal and the directions are opposite.

[0039] By uniformly constraining the generation method of the two test excitations, it is beneficial to reduce the detection error caused by amplitude deviation, phase deviation or trigger timing deviation between independent excitation sources, make the symmetry between the two test excitations more stable, thus making it easier to form a clear and comparable target response relationship, and reduce the risk of misjudgment caused by the inconsistency of the excitations themselves, thereby improving the stability and reliability of adjacent double mutual interchange through-core detection.

[0040] This invention also provides a detection system for adjacent double-phase current transformers in a three-phase metering box, used for detecting the three-phase metering box, wherein the three-phase metering box is a fixed box type and has three current transformers arranged in a fixed manner inside; the detection system includes:

[0041] The processing control unit is used to select two adjacent phases to be checked as target phase pairs without opening the box after the wiring of the external terminals of the three-phase metering box is correct and the power failure continuity test is passed. The target phase pairs include the primary conductor of the first phase and the corresponding first target current transformer, the primary conductor of the second phase and the corresponding second target current transformer, and the remaining primary conductor of the remaining phase and the corresponding current transformer are respectively identified as non-target phase primary conductors and non-target current transformers.

[0042] The excitation unit is used to apply a first-direction test excitation to the first-phase primary conductor, and simultaneously apply a second-direction test excitation to the second-phase primary conductor that is opposite to the first-direction test excitation and has the same amplitude, and to keep the non-target phase primary conductor without test excitation input during the detection cycle;

[0043] The acquisition unit is used to simultaneously acquire the secondary circuit responses of the first target current transformer and the second target current transformer, as well as the secondary circuit responses of the non-target current transformers.

[0044] The processing control unit is further configured to determine whether the target phase pair has undergone a crossover when the secondary circuit response of the non-target current transformer meets the preset residual response limitation conditions, based on the matching result of the secondary circuit responses of the first target current transformer and the second target current transformer with the preset reverse response signature.

[0045] By setting up a processing control unit, an excitation unit, and an acquisition unit, the detection process of adjacent pairs exchanging through the center can form a clear division of system functions. This ensures a clear correspondence between target phase pair determination, differential test excitation application, target and non-target response acquisition, and exchange determination, thereby improving the actual deployment capability, execution stability, and engineering application value of the detection method.

[0046] The present invention also provides a computer-readable storage medium having a computer program stored thereon, characterized in that: when the computer program is executed by a processor, it implements the detection method for adjacent double-interchange cores of a three-phase metering box as described in any one of claims 1 to 8.

[0047] In summary, this application includes the following beneficial technical effects: This invention can perform targeted identification of adjacent double-phase cross-connection points inside a fixed-box three-phase metering box without opening the box. This not only helps to distinguish hidden faults with correct external wiring but abnormal internal cross-connection relationships from ordinary conduction abnormalities, but also, compared with the detection method of phase-by-phase excitation and single-channel main response comparison, it is more conducive to highlighting the paired response characteristics of the target phase pair and suppressing the influence of non-target phase interference on the judgment result, thereby improving the accuracy and reliability of adjacent double-phase cross-connection point detection. Attached Figure Description

[0048] Figure 1 This is a schematic diagram of the structure of the three-phase metering box and detection system provided in one embodiment of the present invention;

[0049] Figure 2 This is a flowchart illustrating a method for detecting adjacent dual-phase cross-connection in a three-phase metering box according to an embodiment of the present invention.

[0050] Reference numerals in the attached diagram: 1. Three-phase metering box; 11. Current transformer; 2. Detection system; 21. Excitation unit; 22. Acquisition unit; 23. Processing and control unit; 24. Result output unit. Detailed Implementation

[0051] To enable those skilled in the art to better understand this solution, the following detailed description of the detection method and system for adjacent double-phase cross-connection in a three-phase metering box, using a typical application scenario, is provided. It should be noted that the following embodiments are for illustrative purposes only and are not intended to limit the scope of protection. Any conventional substitutions or modifications made by those skilled in the art to the relevant structures, connection methods, and signal processing flows without departing from the concept of this solution should fall within the scope of protection of this solution.

[0052] like Figure 1As shown, in the field metering scenario of a power system, a three-phase metering box 1 is typically installed in the user-side distribution circuit, low-voltage metering circuit, or distribution cabinet metering unit to collect and meter the current and energy parameters of the three-phase lines. During actual assembly, maintenance, or replacement, even if the external terminal wiring is correct and the continuity test results are passed under power outage conditions, there may still be abnormalities in the through-core correspondence between the primary conductor and the current transformer inside the box, especially when the primary conductors of adjacent phases are interchanged between adjacent current transformers. These abnormalities are located inside the box and are difficult to observe directly without disassembling it. Ordinary continuity checks cannot directly reflect whether the primary conductor has passed through the correct current transformer. Therefore, a dedicated detection solution is needed that can be implemented under power outage conditions without disassembling the box.

[0053] In this embodiment, the detection object is a fixed-box three-phase metering box 1. A fixed box means that the box structure, internal mounting positions, conductor routing paths, and current transformer arrangement are all predetermined and fixed in design and assembly. Three current transformers are fixedly arranged inside the metering box along a predetermined direction, which can be referred to as the first current transformer, second current transformer, and third current transformer in physical order. Three-phase primary conductors are also arranged inside the box, with each phase primary conductor passing through the corresponding current transformer to form a current detection circuit. Since this embodiment focuses on the anomaly of adjacent double-phase crossover, in subsequent detection, two adjacent phases to be checked are selected from the three-phase primary conductors as the target phase pair, and the remaining phase is designated as the non-target phase. Accordingly, the two primary conductors in the target phase pair correspond to the first target current transformer and the second target current transformer, respectively, and the remaining corresponding current transformer is designated as the non-target current transformer.

[0054] In one example, the two adjacent phases to be checked can be the first two phases that are physically adjacent; in another example, the two adjacent phases to be checked can also be the last two phases that are physically adjacent. In other words, the target phase pair is selected from the three-phase primary conductors according to the adjacency relationship, rather than being a unique correspondence between a specific phase and a specific current transformer that is predetermined at the beginning of this embodiment. The purpose of this setting is to ensure that the subsequent detection logic always revolves around the structure of "target phase pair with one or two target current transformers and one non-target current transformer", so as to specifically determine whether the adjacent two phases have swapped their cores between the two adjacent current transformers.

[0055] To achieve the above-mentioned detection, this embodiment also includes a detection system 2. The detection system 2 can be a portable handheld terminal or a fixed detection device. Its core task is to apply test excitation to the target phase pairs, collect the secondary circuit response of the current transformer, and complete the interchangeability determination based on the collected results, under power failure and without disassembling the casing. The detection system 2 includes at least an excitation unit 21, a data acquisition unit 22, a processing control unit 23, and a result output unit 24.

[0056] The excitation unit 21 is used to apply test excitation to the two primary conductors of the target phase pair. The output of the excitation unit 21 can be connected to the corresponding phase line access position outside the three-phase metering box 1 through a test cable, external access terminal, or dedicated test fixture, so that the test signal can act on the corresponding primary conductor inside the box. The excitation unit 21 should have at least dual-channel synchronous output capability, and under the control of the processing control unit 23, be able to apply test excitations with opposite directions and equal amplitudes to the two primary conductors of the target phase pair, and reverse the two test excitations as a whole when reverse verification is required later. As a preferred implementation, the two test excitations can be generated from the same reference test signal after phase inversion and amplitude balancing to improve the synchronicity and symmetry between the two excitations.

[0057] The acquisition unit 22 is used to acquire the secondary circuit responses of the three current transformers. The input terminal of the acquisition unit 22 can be connected to the secondary side terminal block of the current transformers outside the three-phase metering box 1, so as to acquire the secondary circuit response signals corresponding to the first, second, and third current transformers without disassembling the box. The acquisition unit 22 preferably has at least three independent synchronous sampling channels and may include signal conditioning circuitry, analog-to-digital conversion circuitry, and necessary isolation and protection circuitry, thereby ensuring that the response waveforms from the secondary sides of the three current transformers can be acquired synchronously and stably.

[0058] The processing control unit 23 controls the entire detection process. The processing control unit 23 can be implemented using a microprocessor, a single-chip microcomputer, a digital signal processor, an industrial controller, or a combination thereof. On one hand, the processing control unit 23 controls the excitation unit 21 to generate and output test stimuli; on the other hand, it controls the acquisition unit 22 to perform synchronous sampling and process the acquired response data, completing functions such as target phase pair determination, detection window selection, response quantity extraction, reverse response signature matching, residual response condition judgment, and final conclusion output. In other words, although the subsequent detection method unfolds in steps, its implementation is based on the collaborative work of the software logic executed by the processing control unit 23 and the excitation and acquisition hardware units.

[0059] The result output unit 24 is used to provide feedback on the test results to the operators. The result output can be in the form of a display screen prompt, indicator light display, buzzer alarm, or uploaded to the host computer or background system via a communication interface. Although the focus of the main method is on judgment, setting up the result output unit 24 in the actual system helps to provide feedback on the test results such as interchangeable cores, correct core penetration, or pending verification to the on-site personnel.

[0060] Before implementation, detection system 2 typically confirms that the preconditions are met. These preconditions include: first, confirming the correct wiring of the external terminals; and second, confirming that the continuity test passes under power-off conditions. Here, correct external terminal wiring is used to rule out obvious external wiring errors, and passing the power-off continuity test confirms that the detection circuit is in a detectable state. It should be noted that this preconditioning does not directly determine whether there are interchangeable cores, but rather aims to focus subsequent testing on hidden anomalies that appear normal externally but may still exist inside the enclosure where adjacent double cores are interchanged.

[0061] In addition to the hardware foundation, the method in this embodiment also relies on the program control foundation. Although the subsequent steps are carried out in the form of a detection method, they are essentially implemented by the processing control unit 23 executing program instructions in coordination with the excitation unit 21 and the acquisition unit 22.

[0062] In one implementation, the detection program can be pre-stored in the memory inside the detection system 2, such as flash memory, EEPROM, on-chip memory, or solid-state memory. After the processing control unit 23 is started, it can read and execute the corresponding program instructions to sequentially complete the target phase pair determination, test stimulus application, response acquisition, signature matching, reverse verification, and result output.

[0063] In another embodiment, the relevant program can also be stored in a removable memory card, USB flash drive, or other computer-readable storage medium and executed after being loaded into the processing control unit 23. That is, the implementation of subsequent methods can rely either on a program integrated within the detection system 2 or on a program stored in an external storage medium and invoked by the processor. This description also provides a basis for the storage medium scheme discussed later.

[0064] In summary, in this embodiment, the fixed-box three-phase metering box 1 structure, the fixed arrangement of the three current transformers, the division of adjacent phase pairs and non-target phases, the hardware composition of the detection system 2 and its external access method, and the control basis of the processing control unit 23 for the detection process have all been established. Based on this, the specific detection process of adjacent double-phase cross-connection will be described below in conjunction with the main detection process.

[0065] like Figure 2As shown below, the detection method for adjacent double-phase cross-connection of a three-phase metering box provided in this embodiment will be described in detail.

[0066] In this embodiment, the detection process does not perform a generalized check on all three phases, but rather focuses on a specific anomaly: whether two adjacent phases have experienced a cross-connection between two adjacent current transformers. Therefore, before formally applying the test excitation, it is necessary to confirm the detection boundary and determine the target phase pair, non-target phases, and the three current transformers involved in the judgment.

[0067] Step S1: Determination of target phase and non-target phase

[0068] In this embodiment, the detection system 2 first confirms whether the current three-phase metering box 1 meets the prerequisites for entering the interchange through-hole testing process. These prerequisites include: the external terminal wiring relationship is correct, and the continuity test result is passed under power-off conditions.

[0069] Here, correct external terminal wiring is used to rule out obvious external phase line misconnection, terminal misconnection, or secondary side wiring abnormalities; power failure continuity test results are used to confirm that the current test circuit is continuously usable and there are no obvious open circuits, serious loose connections, or situations where an effective test path cannot be formed.

[0070] It should be noted that the aforementioned preconditions do not necessarily mean that the primary conductor inside the metering box and the current transformer are in a correct through-hole correspondence. Rather, they only indicate that, from an external observation and basic continuity perspective, the current object meets the conditions for entering the dedicated testing process of this embodiment. It is precisely in this scenario, where "the exterior appears normal and the continuity is passed, but there may still be an abnormal through-hole correspondence internally," that the testing in this embodiment has practical significance.

[0071] After confirming that the preconditions are met, the processing control unit 23 selects two adjacent phases to be checked from the three-phase primary conductors as the target phases for this test, and determines the remaining phase as the non-target phase.

[0072] The term "adjacent" here is determined based on the physical arrangement of the three-phase primary conductors in a fixed box configuration. In other words, the target phase pair is not an arbitrarily selected pair of phases, but rather two phases that are adjacent to each other along a predetermined arrangement direction inside the metering box.

[0073] In a typical implementation, the three-phase primary conductors can be numbered sequentially according to their physical arrangement as the first position primary conductor, the second position primary conductor, and the third position primary conductor. Then, the target phase pair that can be selected this time can be an adjacent phase pair composed of the first two phases or an adjacent phase pair composed of the last two phases.

[0074] For example, in one example, the two phases physically located at the front of the array can be selected as the target phase pair for detection; in another example, the two phases physically located at the back of the array can also be selected as the target phase pair. The purpose of this setting is to ensure that subsequent detection always revolves around the specific abnormal object of "adjacent pairs of phases", rather than degenerating into a general check of the overall relationship of the three phases.

[0075] Once the target phase is determined, the processing control unit 23 further completes the object binding in this detection task.

[0076] The first phase primary conductor in the target phase pair is denoted as the first phase primary conductor in this testing task; the current transformer corresponding to the first phase primary conductor participating in this testing is denoted as the first target current transformer.

[0077] The second phase primary conductor in the target phase pair is referred to as the second phase primary conductor in this testing task; the current transformer corresponding to the primary conductor of this phase and participating in this testing is referred to as the second target current transformer.

[0078] The remaining primary conductor of one phase is designated as the non-target primary conductor; the corresponding current transformer participating in this test is designated as the non-target current transformer.

[0079] It is important to note that the terms "first target current transformer," "second target current transformer," and "non-target current transformer" are defined as detection roles established within the current detection task. Their purpose is to provide a unified object basis for subsequent test excitation output, response acquisition, and cross-connection determination, rather than a priori and permanently assigning a phase to a specific current transformer at the beginning of the embodiment. This approach ensures consistency between the specification and the detection logic in the claims; that is, what truly needs to be determined is whether the primary conductors of these two phases have undergone cross-connection between these two adjacent current transformers.

[0080] To facilitate the subsequent unified invocation of the control unit 23, in this embodiment, the set of detection task parameters required for this detection can also be established synchronously in step S1.

[0081] The parameter set may include at least: the current target phase pair identifier; the acquisition channel identifiers corresponding to the first target current transformer, the second target current transformer, and the non-target current transformer; the relative position parameters between the current target phase pair and the non-target phase; the preset reverse response signature template corresponding to the current target phase pair; and the threshold parameters or threshold coefficients related to the residual response limit of the non-target channel.

[0082] In other words, step S1 not only determines "who is being detected," but also prepares a unified data entry and parameter entry for subsequent test stimulus application, synchronous response acquisition, residual response judgment, and reverse response signature matching. This avoids repeatedly switching detection objects, reloading parameters, or rebinding sampling channels in subsequent steps, thus ensuring that the entire backbone detection process is logically continuous and uniform in program execution.

[0083] In an optional implementation, if the detection system 2 has pre-stored parameter templates corresponding to different fixed box types, the processing control unit 23 can also automatically load the corresponding parameter template according to the current box type number in step S1.

[0084] For example, the spacing of the three-phase primary conductors, the installation position of the current transformer, the division method of the candidate target phase pair, and the preset reverse response signature template may be different for different fixed box types. In this case, the processing control unit 23 can first match the corresponding template according to the box type number, and then determine the current target phase pair based on the template.

[0085] In another alternative implementation, if the objects being tested on-site are all three-phase metering boxes 1 of the same batch and type, the relevant templates and parameters can also be pre-fixed in the testing program. During testing, the operator only needs to select whether the current phase to be checked is the first two phases or the last two phases.

[0086] Through the above steps, this embodiment has completed three levels of preparation before formally outputting test stimuli: First, it confirms that the current object belongs to a valid testing scenario where "external wiring is normal, continuity test passes, but internal through-core anomalies may still exist"; second, it completes the classification of testing roles for the target phase pair, non-target phases, and the corresponding three current transformers; third, it completes the loading of the channels, parameters, and signature templates required for subsequent testing. It is only after completing these preparations that subsequent steps can establish a dedicated response relationship around the target phase pair, rather than remaining at a general three-phase overall test.

[0087] After completing step S1, the processing control unit 23 further controls the excitation unit to apply test excitation only to the two primary conductors of the target phase pair, while keeping the primary conductors of the non-target phases from being tested during the detection cycle. The process of applying the test excitation is described below.

[0088] Step S2: Apply equal-amplitude reverse test excitation to the target phase simultaneously.

[0089] After completing the detection role assignment for the target phase pair, non-target phases, and the corresponding three current transformers in step S1, the processing control unit 23 begins to control the excitation unit 21 to enter the test excitation output stage. In this embodiment, the test excitation is not applied simultaneously to all three primary conductors, nor is it performed sequentially in a conventional phase-by-phase injection manner. Instead, a set of synchronous, reverse, and equal-amplitude dual-channel test excitations is established only around the two primary conductors in the current target phase pair. In this way, the subsequent detection basis is no longer a "comparison of the general response of the three phases as a whole," but rather a set of paired responses with a clear correspondence formed around the target phase pair.

[0090] In a typical implementation, once the current target phase pair has been determined to be the first phase primary conductor and the second phase primary conductor, the excitation unit 21 outputs a first-direction test excitation to the first phase primary conductor and a second-direction test excitation to the second phase primary conductor within the same detection cycle. The second-direction test excitation is opposite in direction to the first-direction test excitation, equal in amplitude, and the start times of the two test excitations are synchronized.

[0091] Here, "direction" can be understood as the direction of the test current applied to the primary conductor, the polarity of the test voltage, or the direction of the excitation output under a unified reference definition. In other words, as long as the two test excitations satisfy a logical relationship of one being positive and the other negative, they can constitute opposite-direction test excitations in the current implementation. "Equal amplitude" means that the two test excitations have the same amplitude reference during the target detection stage, making the response relationship formed by the subsequent target channel more suitable for pairwise comparison. During the application of the test excitation, the remaining primary conductor of the current detection cycle, i.e., the non-target primary conductor, does not participate in the test excitation input, making the subsequent response acquired from the non-target current transformer more suitable for analysis as a non-target residual response.

[0092] Step S2-1: Method for generating test stimuli

[0093] To ensure the synchronization and symmetry between the dual-channel test excitations, in this embodiment, the two test excitations are preferably generated from the same reference test signal. More specifically, the excitation unit 21 can first generate a reference test signal, which can be an AC test signal with a preset amplitude, a pulse-type test signal output according to a predetermined waveform, or a low-frequency variation test signal.

[0094] Based on this, the excitation unit 21 splits the reference test signal into two paths: one path is directly used as the first direction test excitation output; the other path is inverted to form the second direction test excitation. In order to further ensure that the two excitations maintain an equal amplitude relationship when actually output to the primary conductor, amplitude balancing processing can be performed on the second test excitation after inversion, and if necessary, the corresponding amplitude calibration can also be performed on the first excitation at the same time.

[0095] By generating two test stimuli from the same reference test signal, and then inverting one of them and balancing the amplitude of both test stimuli, the start-up time of the two test stimuli can be based on the same reference clock or the same trigger control, thereby reducing the amplitude deviation, phase deviation and trigger asynchrony problems that may occur when independent excitation sources output separately.

[0096] In a understandable example, if the benchmark signal is denoted as Then the first test stimulus can be expressed as:

[0097]

[0098] The second-path test stimulus can be represented as:

[0099]

[0100] in, and Let be the amplitude balancing factor. After amplitude balancing is completed, let and By satisfying an equal or approximately equal relationship, the two test excitations can form a test relationship with opposite directions and equal amplitudes when output to the primary conductors of the first and second phases. In practical engineering implementation, amplitude balancing can be achieved through analog gain adjustment circuits, amplitude parameter calibration in digital waveform generation modules, or by combining factory calibration parameters or field self-calibration parameters.

[0101] During the application of test excitation, the remaining primary conductor of the current detection cycle, i.e., the non-target phase primary conductor, does not participate in the test excitation input. In other words, in this detection cycle, the excitation unit 21 only establishes dual-channel test excitation for the two primary conductors of the target phase pair, and does not actively inject test excitation signals into the non-target phase primary conductor. This setting has two effects:

[0102] Firstly, it can prevent the non-target phase from playing the role of the main detection object in this detection cycle, so that the response collected from the non-target current transformer in the future is more suitable for analysis as the "non-target residual response".

[0103] Secondly, it can enable a clear division of labor among the three responses in the subsequent detection process: two target responses are used to establish the basis for interchangeable core determination, and one non-target response is used to constrain or eliminate interference from non-target channels.

[0104] In terms of timing control, the processing control unit 23 can divide a single detection cycle into an excitation establishment phase, an excitation stabilization phase, and an excitation removal phase.

[0105] The stimulus setup phase is used to transition the two test stimuli from zero to the set output state; the stimulus stabilization phase is used to maintain the synchronous output and amplitude stability of the first and second direction test stimuli; the stimulus removal phase is used to end the current test cycle, so that the two test stimuli gradually or quickly return to the zero output state.

[0106] The detection window involved in subsequent steps is generally set within the time interval corresponding to the stable phase of the excitation, rather than directly using the transient interval when the excitation is just established or removed.

[0107] The purpose of this is to provide a more stable time-domain basis for subsequent response acquisition and actual response polarity extraction, and to reduce the interference of establishing and removing transients on the target channel response and non-target channel response.

[0108] In one implementation example, after completing step S1, the processing control unit 23 can first output a synchronous trigger command to start the reference test signal generation module inside the excitation unit 21; then, through the inverting branch and the amplitude balancing branch, two output signals are formed respectively, and test excitations are synchronously applied to the first phase primary conductor and the second phase primary conductor under the same clock reference.

[0109] In another implementation example, the excitation unit 21 can also adopt a dual-channel digital waveform generator structure. However, these two digital waveform generators do not operate independently. Instead, they are controlled by the same master clock and the same synchronous trigger signal, and are balanced by an amplitude calibration module before output. This forms an implementation method that is technically equivalent to "generating the same reference test signal after inversion and amplitude balancing". In other words, this embodiment does not limit the excitation unit 21 to a single circuit structure, but emphasizes that as long as the two test excitations can be synchronized at the start time, have equal amplitudes, and opposite directions, the requirements in step S2 of this application can be met.

[0110] Furthermore, in some extended embodiments, to further improve the stability of on-site testing, a zero-point calibration or amplitude self-checking process can be added before the excitation output. For example, before formal testing, the testing system 2 can output a set of short-time test excitations under no-load or standard reference load conditions, detect the amplitude error and phase error between the two outputs through the internal calibration circuit, and automatically adjust the balancing coefficient.

[0111] For example, during the testing process, if the processing control unit 23 detects that the output amplitude deviation of the excitation unit 21 exceeds the preset tolerance range, it can also stop the current testing cycle and issue a prompt to avoid entering the subsequent judgment with obviously asymmetrical test excitation.

[0112] While these contents may not necessarily need to be included in the current main claims, embedding them in specific embodiments can enhance the engineering feasibility of the solution and facilitate subsequent supplementary explanations based on examination opinions.

[0113] Through the above steps, this embodiment has established a synchronous, reverse, and equal-amplitude dual-channel test excitation relationship on the primary conductors of the two phases in the current target phase pair, while keeping the primary conductors of the non-target phases without test excitation input within the same detection cycle. This ensures that the secondary circuit responses subsequently acquired from the three current transformers are no longer isolated responses from a single channel, but rather form a detection structure of "two paired responses of the target phase pair and one residual response of the non-target phase".

[0114] It is on this basis that subsequent steps can simultaneously collect the secondary circuit responses of the two target current transformers and one non-target current transformer, and further determine whether the target phase pairs have swapped their cores.

[0115] Step S3: Synchronously acquire the secondary circuit responses of the target current transformer and the non-target current transformer.

[0116] In step S2, two synchronous, opposite-direction, and equal-amplitude test excitations have been established around the current target phase pair, and the primary conductor of the non-target phase is kept out of the test excitation input during the same detection cycle. Based on this, detection system 2 enters the response acquisition stage. The core task of this step is to synchronously acquire the secondary circuit responses of the two target current transformers corresponding to the target phase pair, as well as the secondary circuit response of the non-target current transformer corresponding to the remaining phase pair, within the current detection cycle. This provides a unified data foundation for subsequent non-target residual response judgment and target channel signature matching.

[0117] In this embodiment, under the control of the processing control unit 23, the acquisition unit 22 simultaneously activates three sampling channels corresponding to the first target current transformer, the second target current transformer, and the non-target current transformer to synchronously sample the responses of the three secondary circuits. This "synchronous sampling" does not require the three channels to share the same analog-to-digital converter in physical structure. Rather, it requires that the three response data be acquired under the same clock reference, the same detection period, and unified timing control, so that the response relationship between the target channel and the non-target channel can be analyzed within the same time reference system. In other words, this step emphasizes not simply "acquiring data from the three channels," but ensuring that these three data points correspond in the time dimension, avoiding the impact on subsequent judgments due to different sampling starting points, clock drift, or differences in acquisition delays.

[0118] In a typical implementation, the three sampling channels of the acquisition unit 22 can be connected to the secondary circuits of three current transformers, respectively. The first sampling channel corresponds to the first target current transformer, the second sampling channel corresponds to the second target current transformer, and the third sampling channel corresponds to the non-target current transformer. The processing control unit 23 sends a synchronous sampling start command to the acquisition unit 22 simultaneously with the issuance of a synchronous start command for the two test excitations, enabling the three channels to record the secondary circuit response from the same detection starting point. In another implementation, sampling can also begin before the test excitation reaches a stable output, ensuring that the sampled data covers the excitation setup phase, the excitation stabilization phase, and the excitation removal phase. This approach facilitates subsequent extraction of preset detection windows, identification of the initial transient interval and the removed transient interval from the complete response waveform, and extraction of the truly effective response segments for judgment, based on different analysis objectives.

[0119] The secondary circuit response acquired in this step can be a sampled current signal proportional to the secondary current of the current transformer, a sampled voltage signal converted by a sampling resistor and signal conditioning circuit, or other electrical quantities that can characterize the response state of the secondary side of the current transformer. As long as the response quantity can reflect the time-domain variation characteristics of the target phase and non-target phases under test excitation within the detection period, it can be used as the basic data for subsequent analysis.

[0120] In a preferred embodiment, the acquisition unit 22 converts the three secondary loop responses into a unified digital response sequence, which is then denoted as the first target response sequence, the second target response sequence, and the non-target response sequence, respectively. This facilitates subsequent processing such as detection window capture, waveform integration, polarity sign determination, and threshold comparison using a unified data format.

[0121] For ease of subsequent analysis, in this embodiment, the response waveforms acquired by the first target current transformer, the second target current transformer, and the non-target current transformer during the current detection period can be represented as follows:

[0122]

[0123] in, This indicates the secondary circuit response of the first target current transformer during the current detection cycle. This indicates the secondary circuit response of the second target current transformer during the current detection cycle. This indicates the secondary circuit response of the non-target current transformer during the current detection cycle. This represents the time variable under a unified sampling clock. Subsequent actions, such as determining whether a non-target current transformer meets the residual response constraint, extracting the actual response polarity from the responses of the two target current transformers, and performing preset reverse response signature matching, can all be performed under this unified time reference.

[0124] The reason why we need to simultaneously collect the secondary circuit responses of two target current transformers and one non-target current transformer in this step, instead of only collecting the two target responses of the target phase pair, is mainly because:

[0125] On the one hand, the secondary circuit responses of the two target current transformers are the core data for establishing the basis for subsequent interchangeability determination. In subsequent steps, it is necessary to extract the actual response polarity from these two responses and determine whether their affiliation on the fixed channel matches the preset reverse response signature. On the other hand, although the non-target current transformers do not participate in the main determination of the current target phase pair, their secondary circuit responses can reflect whether there are residual responses exceeding the allowable range in the non-target channels during the current detection cycle. Without synchronous acquisition of this channel, it becomes difficult to determine whether non-target phase interference has been mixed into the current detection results, and thus, it is impossible to constrain the detection boundary before actually performing target signature matching.

[0126] To improve the stability of the acquisition results, in one embodiment, the acquisition unit 22 can set consistent signal conditioning links before the three input channels, such as filter circuits with the same bandwidth, preamplifier circuits with the same gain, and consistent isolation protection structures. The purpose of this is to minimize channel response imbalances caused by differences in the sampling links themselves, so that subsequent comparisons between target channels and between target / non-target channels better reflect the differences in the object under test itself, rather than the systematic errors of the measurement links. In another embodiment, the processing control unit 23 can also perform zero-point calibration or baseline acquisition on the three sampling channels before sampling begins, so as to subtract static offsets in subsequent processing.

[0127] In this embodiment, after the three-channel response acquisition is completed, the processing control unit 23 can temporarily store the raw response data in a buffer or storage unit, and further generate a data record corresponding to the current detection task. This data record may include at least the following:

[0128] Current detection task identifier; response data corresponding to the first target current transformer; response data corresponding to the second target current transformer; response data corresponding to the non-target current transformer; time parameters related to sampling, such as sampling start point, sampling period, sampling frequency and detection period identifier; parameters related to excitation, such as the output direction, output amplitude and synchronous trigger time of the two test excitations in the current detection period.

[0129] By recording these data uniformly under the same detection task, subsequent steps can not only make immediate judgments using the three-way response, but also review, replay, or debug and analyze the detection results when needed.

[0130] For example, in some extended implementations, if subsequent consistency comparison results show abnormal coupling that needs to be verified, the three original response data saved in this step can be retrieved to further compare and analyze the response differences between the two detection cycles.

[0131] In an optional implementation, the processing control unit 23 may further preprocess the three acquired responses after this step. This preprocessing may include: removing DC bias; filtering out significant high-frequency noise; normalizing the amplitude according to the sampling gain or calibration parameters; and performing uniform time-base resampling on the response waveform.

[0132] It should be noted that these preprocessing steps do not change the core logic of "synchronously acquiring the responses of three secondary loops" in this step, but rather serve as a data processing method before subsequent judgment. As long as the intrinsic correspondence between the target channel and the non-target channel is not changed, the relevant preprocessing can be used as an optional implementation in this embodiment.

[0133] Through the above steps, this embodiment has obtained the secondary circuit responses of two target current transformers and one non-target current transformer within the same detection cycle, and established the three responses under the same time reference, the same excitation background and the same detection task.

[0134] In this way, the subsequent steps can first use the response of the non-target current transformer to determine whether the current detection meets the residual response constraint condition. Then, when the condition is met, the actual response polarity is extracted based on the responses of the two target current transformers and matched with the preset reverse response signature to determine whether the current target phase pair has swapped the core.

[0135] Step S4: Determine based on residual response constraints and reverse response signature.

[0136] In step S3, the processing control unit 23 has acquired the secondary circuit responses of the first target current transformer, the second target current transformer, and the non-target current transformer within the same detection cycle.

[0137] Based on this, this embodiment does not immediately perform a cross-connection judgment on the responses of the two target current transformers, but first performs a constraint judgment on the secondary circuit response of the non-target current transformer.

[0138] Only when the response of the non-target channel is within the allowable range can the response relationship formed by the target channel be used as a valid basis for subsequent cross-channel determination; if the response of the non-target channel exceeds the allowable range, the residual influence of the non-target phase that exceeds the normal allowable range may be mixed in during the current detection cycle, thereby affecting the subsequent determination.

[0139] Therefore, step S4 adopts the processing logic of "first performing non-target channel constraints, then performing target channel main determination". Only when the secondary circuit response of the non-target current transformer meets the preset residual response limit condition will the responses of the two target current transformers be used to match the preset reverse response signature; otherwise, the data obtained in the current detection cycle will not be directly used as the input basis for the main determination of the interchange channel.

[0140] In a typical implementation, the processing control unit 23 first extracts a non-target response amplitude from the secondary circuit response of the non-target current transformer to characterize its response strength. This non-target response amplitude can be obtained in various ways, such as by using the peak value, RMS value, absolute average value, envelope amplitude, or integral amplitude of the response waveform within a preset detection window.

[0141] In a preferred embodiment, to maintain consistency with the amplitude comparison of the response of the subsequent target channel, the response amplitudes of the first target current transformer, the second target current transformer, and the non-target current transformer can be extracted separately within a unified detection window, and these three values ​​are respectively denoted as:

[0142]

[0143] in, This indicates the response amplitude of the first target current transformer within the current detection window. This indicates the response amplitude of the second target current transformer within the current detection window. This indicates the response amplitude of the non-target current transformer within the current detection window.

[0144] The detection window here can be the same as the detection window used for subsequent target response polarity extraction, or it can be a window that corresponds to it in time but is more suitable for amplitude evaluation, as long as the three responses are all established under the same detection period and unified time reference.

[0145] S4-1: Determination of Residual Response Threshold and Relative Position Parameters

[0146] In this embodiment, the residual response limitation condition of the non-target current transformer is not simply constituted by a fixed empirical threshold, but includes a residual response threshold set for the secondary circuit response of the non-target current transformer. This residual response threshold is not set independently of the actual spatial structure, but is preset or calibrated based on the relative position parameters of the target phase pair and the primary conductor of the non-target phase in the fixed box-type three-phase metering box 1. That is to say, under the fixed box type, the relative positional relationship between the target phase pair and the non-target phase is deterministic, so the residual response allowed in the non-target channel can be set in combination with this spatial relationship.

[0147] In one specific embodiment, the aforementioned relative position parameter includes at least two parts. The first part is the center distance between the two primary conductors of the target phase pair. For example, if the centerline positions of the two primary conductors of the target phase pair are respectively denoted as... and The center distance between the two can be expressed as:

[0148]

[0149] The second part is the geometric distance from the non-target phase primary conductor to the target phase pair.

[0150] In this embodiment, to facilitate calculation and maintain a consistent definition, the geometric distance is preferably defined as: the shortest distance from the center line of the primary conductor of the non-target phase to the center line of the line connecting the center lines of the primary conductors of the two phases in the target phase pair.

[0151] If the position of the centerline of the primary conductor of the non-target phase is denoted as Then the geometric distance can be expressed as:

[0152]

[0153] Of course, without changing the technical essence, the geometric distance can also be defined in other equivalent ways that can characterize the spatial proximity between the non-target phase and the target phase pair. For example, it can be the distance from the primary conductor of the non-target phase to the geometric center of the target phase pair, or the shortest distance from the primary conductor of the non-target phase to the nearest primary conductor in the target phase pair. In this embodiment, the aforementioned "shortest distance to the centerline of the target phase pair" is preferably used as the geometric distance.

[0154] After obtaining the relative position parameters, the processing control unit 23 or the preset parameter library can further form the residual response threshold corresponding to the current target phase.

[0155] In one implementation, the residual response threshold can be calibrated offline at the factory stage based on the same fixed box-type prototype and stored in a parameter library; during on-site testing, the processing control unit 23 calls the corresponding threshold parameter according to the current box-type number and the current target phase pair. In another implementation, it can also be based on the center distance of the target phase pair in the current box type. Geometric distance between the non-target phase and the target phase Calculate or correct residual response thresholds in real time.

[0156] Whether pre-calibrated or calculated in real time, the residual response constraints are linked to the spatial relationships under the current fixed box configuration.

[0157] To further improve the stability of residual response determination, in this embodiment, the residual response threshold is preferably configured with both absolute threshold conditions and relative threshold conditions. The absolute threshold condition constrains the non-target channel response itself from exceeding an upper limit; the relative threshold condition constrains the non-target channel response to be sufficiently small relative to the responses of the two target channels.

[0158] If only absolute thresholds are used, the normal residual response of non-target channels may also increase when the overall test stimulus is strong; if only relative thresholds are used, even small fluctuations in non-target channels may be amplified when the responses of the two target channels are weak. Therefore, combining absolute and relative threshold conditions is more suitable for the current detection scenario.

[0159] In a preferred embodiment, the absolute threshold condition can be expressed as:

[0160]

[0161] in, This indicates the absolute threshold value set or calibrated for the current fixed box type and the current target phase.

[0162] The relative threshold condition can be expressed as:

[0163]

[0164] in, This represents a relative threshold.

[0165] Furthermore, the relative threshold is preferably determined based on the smaller of the response amplitudes of the two target current transformers.

[0166] For example, it can be defined as:

[0167]

[0168] in, This is a preset proportional coefficient. This represents the smaller of the secondary circuit response amplitudes of the first target current transformer and the second target current transformer.

[0169] Therefore, the relative threshold condition can be further written as:

[0170]

[0171] Even if the response amplitudes of the two target current transformers are not completely consistent in a certain detection cycle, the smaller one is still used as the comparison benchmark, thereby making the constraints on the non-target residual response more stringent.

[0172] Therefore, in this embodiment, the non-target current transformer satisfies the residual response constraint condition, which can preferably be understood as the following two conditions being met simultaneously:

[0173]

[0174] and

[0175]

[0176] When the above conditions are met simultaneously, the processing control unit 23 can consider that the response of the non-target channel within the current detection cycle is within the allowable residual range, and the current detection data has the condition to continue to enter the target channel signature matching.

[0177] If any condition is not met, it means that the response of the non-target channel in the current detection cycle exceeds the allowable boundary. At this time, instead of directly giving the interchange pass-through judgment based on the target channel response, the current detection cycle is marked as having abnormal coupling or interference risk and handed over to the subsequent review process or abnormal output process for processing.

[0178] In one alternative implementation, absolute threshold It can also be written as a function related to relative position parameters.

[0179] For example, in certain fixed box types, the geometric distance between the non-target phase primary conductor and the target phase varies. As the distance between the target phases and the center can decrease, the upper limit of the allowable residual response can be adjusted accordingly; for example, when the target phases are respectively... When the absolute threshold is increased or decreased, it can also be changed according to a preset mapping relationship.

[0180] For example, the following functional relationship can be used:

[0181]

[0182] in, This can be a lookup function, a fitting function, or a piecewise function obtained through calibration. This functional relationship further demonstrates that the residual response threshold, based on the pre-setting or calibration of the relative position parameters, has a clear technical basis for implementation.

[0183] After completing the above judgment, the processing control unit 23 can distinguish the current detection cycle into two categories:

[0184] The first scenario is that the non-target current transformer meets the residual response constraint, and the current detection cycle can continue to be used for the target channel's interchangeability determination. The second scenario is that the non-target current transformer does not meet the residual response constraint, and the current detection cycle does not directly enter the target signature matching, but is recorded as an abnormal detection cycle. Through this processing, the subsequent signature matching and polarity attribution determination of the target channel are all based on the data that has passed the boundary constraints of the non-target channel.

[0185] After the non-target current transformers meet the residual response constraint conditions, the processing control unit 23 further enters the target channel determination stage. That is, based on the secondary circuit responses of the first and second target current transformers, the actual response polarity is extracted and matched with the preset reverse response signature to determine whether the current target phase pair has undergone a crossover. This process is explained below.

[0186] S4-2: Target Channel Response Polarity Extraction and Reverse Response Signature Matching

[0187] In this embodiment, the preset reverse response signature is not an abstract label, but a response polarity relationship that corresponds to the current target and can be assigned to a fixed channel.

[0188] More specifically, in the current detection task, the processing control unit 23 pre-establishes a first polarity response relationship between the fixed channel of the first target current transformer and the first direction test excitation, and a second polarity response relationship between the fixed channel of the second target current transformer and the second direction test excitation.

[0189] The "fixed channel" here can be understood as the acquisition channel in detection system 2 that is stably connected to the secondary circuit of the corresponding target current transformer and corresponds one-to-one. In other words, during the current detection task, the response of the first target current transformer is always received by the first target sampling channel, and the response of the second target current transformer is always received by the second target sampling channel; their physical channel positions do not change regardless of whether the current transformer is swapped later. Since the physical affiliation of the fixed channel in detection system 2 remains unchanged, the location of the response polarity on which fixed channel it falls into can be used as one of the criteria for identifying swapped current transformers.

[0190] In a typical implementation, the processing control unit 23 first extracts the actual response polarity from the secondary circuit responses of the first and second target current transformers. Here, the "actual response polarity" is not obtained by directly and roughly reading a momentary symbol over the entire sampling period, but rather by processing the valid response data within a preset detection window. The preset detection window is preferably located within the time overlap interval between the first-direction test excitation and the second-direction test excitation, excluding the initial transient response interval during the initial setup of the test excitation and the removal transient response interval during the excitation removal phase. This setting helps to establish the polarity determination of the target channel within the stable setup time interval of the dual-channel test excitation, thereby reducing the impact of initial overshoot, removal fluctuations, or transient imbalances on the polarity determination.

[0191] In a preferred embodiment, the processing control unit 23 extracts the signed response quantities of the first target current transformer and the second target current transformer respectively within the aforementioned preset detection window, and uses these as the basis for determining the actual response polarity. Here, "signed response quantity" refers to a response quantity that reflects not only the strength of the response but also its direction or positive / negative attribute. This signed response quantity can be obtained in various ways, such as using the integral value of the response waveform within the detection window, the phase sign quantity obtained by comparing with a reference benchmark, or the polarity sign quantity of the dominant waveform polarity. In a preferred embodiment, the integral value of the response waveform within the detection window is preferably used as the signed response quantity.

[0192] For example, if the preset detection window is denoted as The response waveforms of the first and second target current transformers within this window are respectively denoted as... and Then the two signed responses can be expressed as follows:

[0193]

[0194] in, This represents the signed response of the first target current transformer within the preset detection window. This represents the signed response of the second target current transformer within the preset detection window.

[0195] when When the value is greater than zero, the actual response polarity of the first target current transformer on its fixed channel during the current detection cycle can be considered as the first polarity; when... When the value is less than zero, its actual response polarity can be considered to be the second polarity, opposite to the first polarity. The actual response polarity of the second target current transformer can be similarly determined by... The symbol is determined.

[0196] In certain implementation scenarios, phase sign or polarity sign may be more suitable for on-site detection conditions. Alternatively, the actual response polarity of the target channel can be determined by comparing the phase lead / lag relationship between the response waveform and the reference signal, or by considering the positive or negative attribute of the dominant half-cycle of the response waveform. The extraction of actual response polarity is not limited to a single mathematical expression, but its core lies in converting the target channel response into a directional determination quantity that can be used for fixed channel attribution within a preset detection window.

[0197] After obtaining the actual response polarities of the first and second target current transformers, the processing control unit 23 further matches them with a pre-established reverse response signature. This reverse response signature can preferably be understood as: under the current target phase pair, current test excitation direction, and current fixed channel definition, a predetermined polarity assignment relationship that the two target current transformers should exhibit on their respective fixed channels.

[0198] In one example, if the current testing task specifies that under a first-direction test excitation, the fixed channel of the first target current transformer should exhibit a first-polarity response, and under a second-direction test excitation, the fixed channel of the second target current transformer should exhibit a second-polarity response opposite to the first polarity, then this relationship of "first fixed channel is first polarity, second fixed channel is second polarity" constitutes the preset reverse response signature corresponding to the current target phase pair. If the current box type or current wiring direction definition is different, the preset reverse response signature can also adopt another set of fixed channel polarity attribution relationships corresponding to it. Therefore, the reverse response signature is not a symbol that exists in isolation from the box type, channel, and direction definitions, but rather a response template that is jointly bound to the current target phase pair, the current test excitation direction, and the current fixed channel allocation.

[0199] In this embodiment, the determination of interchangeable current transformers does not simply rely on "which response is larger" or "whether the two responses are positive and negative," but rather focuses on whether the actual response polarities of the two target current transformers are reversed relative to the aforementioned first and second polarity response relationships in their respective fixed channels. In other words, if, in the current detection cycle, the actual response polarities extracted from the secondary circuit responses of the first and second target current transformers, and their corresponding placement on the fixed channels of the first and second target current transformers, are consistent with the pre-established first and second polarity response relationships, then the current target phase pair does not exhibit interchangeable current transformer characteristics. Conversely, if the actual response polarities of these two paths are reversed relative to the predetermined relationship in their fixed channels, it indicates that the current target phase pair has already exhibited interchangeable current transformer characteristics between the two adjacent current transformers.

[0200] To facilitate understanding, a simplified example can be given. Assume that under the normal state corresponding to the current target phase pair, the fixed channel of the first target current transformer should exhibit a positive polarity response, and the fixed channel of the second target current transformer should exhibit a negative polarity response. That is, the preset reverse response signature can be simplified as follows:

[0201]

[0202] If the actual response polarity result extracted within the current detection period is also: This indicates that the fixed channel polarity of the current target channel has not been reversed, and it can be considered that the current target phase pair has not undergone a crossover.

[0203] If the actual response polarity result extracted in the current detection period becomes: This indicates that the actual response polarity on the target channel has been reversed relative to the preset reverse response signature, and it can be determined that the current target phase pair has undergone a crossover. In actual implementation, the processing control unit 23 can also store and compare signatures by channel number, polarity flag bit, or lookup table template.

[0204] In a preferred embodiment, the processing control unit 23 can further abstract the target channel polarity determination process under the current detection task into the following logic: First, based on the signed response quantity within the preset detection window, determine the actual response polarity of the first target current transformer and the second target current transformer on their respective fixed channels; then, compare these two polarity results with the preset reverse response signature corresponding to the current target phase pair; if the comparison result shows that the fixed channel affiliation has reversed, output the determination result "target phase pair has swapped cores"; if the comparison result shows that the fixed channel affiliation has not reversed, output the determination result "target phase pair core relationship is normal". In some extended embodiments, consistency confidence judgment or amplitude validity judgment can also be introduced, for example, only when the amplitudes of both target channels are higher than the minimum valid amplitude threshold, is it allowed to enter the signature matching stage.

[0205] Through the above steps, the identification of target phase pair interchange is based on the response polarity attribution relationship on a fixed channel. The first part constrains the detection boundary using the residual response limitation condition of the non-target current transformer, and the second part completes the main determination through actual response polarity extraction and reverse response signature matching. Together, these two parts constitute the complete judgment logic for whether the target phase pair has undergone interchange within the current detection cycle. After the first determination result has been given in the current detection cycle, to further reduce the impact of accidental disturbances, contact differences, or excitation imbalances in a single detection on the final conclusion, this embodiment can also perform a reverse verification process in subsequent steps. This process is described below.

[0206] S4-3: Reverse verification and final test result output

[0207] In the aforementioned steps, the processing control unit 23 has obtained the first judgment result corresponding to the current detection cycle based on the residual response constraints of the non-target current transformer and the matching results between the two target current transformers and the preset reverse response signature. However, in actual field testing, a single detection may still be affected by local contact differences, unbalanced test excitation output, transient coupling fluctuations, or external random interference. To avoid misjudgment caused by giving a final conclusion based solely on a single detection result, this embodiment further sets up a reverse verification process after completing the first judgment of the current detection cycle to reconfirm the previous judgment result.

[0208] The reverse verification in this embodiment is not simply a mechanical repetition of the original detection process. Instead, while keeping the definitions of the target phase pair, target current transformer, and non-target current transformer unchanged, the directions of the two test excitations applied to the first and second phase primary conductors are simultaneously reversed, and the second detection cycle is executed again accordingly. That is, if the first phase primary conductor receives a test excitation in the first direction and the second phase primary conductor receives a test excitation in the opposite direction in the first detection cycle, then in the second detection cycle, the first phase primary conductor receives a test excitation in the opposite direction to the first, and the second phase primary conductor also receives a test excitation in the opposite direction to the corresponding direction in the first. Through this overall reverse approach, the two detections maintain consistency in the target object, detection boundary, acquisition channel, and judgment logic, changing only the excitation direction relationship, thus forming a symmetrical verification structure.

[0209] In a typical implementation, after obtaining the first determination result, the processing control unit 23 first resets the two test stimuli in the current detection cycle, and then calls the stimuli unit 21 again to execute the second detection cycle. The execution flow of the second detection cycle is consistent with the first detection cycle in its main structure, that is, it still includes:

[0210] Two synchronous, opposite, and equal-amplitude test excitations are applied to the primary conductors of the first and second phases; no test excitation input is applied to the primary conductor of the non-target phase during this detection cycle; the secondary circuit responses of the first target current transformer, the second target current transformer, and the non-target current transformer are simultaneously acquired; it is first determined whether the non-target current transformer meets the residual response constraint condition; after meeting the residual response constraint condition, the actual response polarity of the two target current transformers is matched with the preset reverse response signature. Therefore, the second detection cycle is a re-detection process that verifies the first detection result using reverse excitation within the same detection framework.

[0211] To facilitate the distinction between the results of two consecutive tests, in this embodiment, the result obtained in the first test cycle is recorded as the first determination result, and the result obtained in the second test cycle is recorded as the second determination result.

[0212] The first and second determination results can be of the same type, for example, both can be "target phase pair has swapped cores" or "target phase pair core relationship is normal"; in the preferred implementation of this embodiment, the first and second determination results are mainly used for subsequent consistency comparison.

[0213] In a preferred embodiment, after obtaining the second determination result, the processing control unit 23 performs a consistency comparison between the first and second determination results. This consistency comparison does not involve comparing each point of the two detection waveforms to ensure they are identical, but rather determining whether the two detections are consistent at the level of the conclusion that "exchange through-core has occurred." In other words, if both detections conclude that "exchange through-core has occurred," or both conclude that "the through-core relationship is normal," the two determination results are considered consistent; if the two detection conclusions are opposite, the two determination results are considered inconsistent. In this way, the focus of reverse verification is not on requiring the two detection waveform values ​​to completely overlap, but on examining whether the detection conclusion remains stable under overall reverse excitation conditions.

[0214] In one example, if the first determination result of the first detection cycle is "target phase pair has swapped through each other", and the second determination result of the second detection cycle is also "target phase pair has swapped through each other", then the processing control unit 23 can determine that the two detection results are consistent and output a definitive conclusion that adjacent pairs have swapped through each other. In another example, if the first determination result of the first detection cycle is "target phase pair has a normal through-heart relationship", and the second determination result of the second detection cycle is also "target phase pair has a normal through-heart relationship", then the processing control unit 23 can determine that the two detection results are also consistent and output a definitive conclusion that the through-heart relationship is correct. Furthermore, if the determination results of the first and second detection cycles are opposite to each other, for example, the first determination is "swapping through each other" and the second determination is "through-heart relationship is normal", or the first determination is "through-heart relationship is normal" and the second determination is "swapping through each other", then the processing control unit 23 does not directly take either single detection result as the final conclusion, but outputs the detection conclusion "abnormal coupling needs to be verified".

[0215] Therefore, in this embodiment, the consistency comparison result between the first determination result and the second determination result is preferably used as the basis for the final detection conclusion output. More specifically, in a preferred embodiment, the final output can be executed according to the following logic:

[0216] When the first judgment result is consistent with the second judgment result, a definite conclusion of adjacent double mutual exchange of cores or correct cores is output based on the consistent judgment result; when the first judgment result is inconsistent with the second judgment result, a detection conclusion of abnormal coupling pending verification is output.

[0217] If expressed using a logical expression, the first decision result can be denoted as: The second judgment result is recorded as The final test result It can be represented as:

[0218]

[0219] Among them, when hour, and Both can be either "interchangeable core" or "correct core"; when If the result is negative, it indicates that the two tests did not form a stable and consistent judgment result under the overall reverse verification condition. In this case, it is preferable not to directly output a definite conclusion of interchangeable core or correct core, but to leave it as pending verification.

[0220] In one optional implementation, when the output "Abnormal coupling pending verification" is received, the processing control unit 23 can also simultaneously record the three original response data corresponding to the first and second detection cycles, the extracted signed response quantity, the response amplitude of the non-target current transformer in the two detections, and the two signature matching results, for subsequent manual verification, host computer analysis, or a third supplementary detection. For example, the operator can check whether the test fixture is making stable contact, whether the wiring of the detection system 2 is in place, or re-execute the detection process according to the prompts on the equipment interface. In another implementation, the detection system 2 can also automatically trigger a supplementary detection cycle when the two judgment results are inconsistent, to further improve the robustness of field use. These contents can be used as extended implementation forms in the embodiments.

[0221] With the above settings, the reverse verification process ensures that the final detection conclusion no longer relies solely on a single detection, but is based on two corresponding detection results in the same direction of the stimulus, thereby improving the stability of the final conclusion.

[0222] In summary, this embodiment focuses on detecting whether adjacent two-phase current transformers in a fixed-box three-phase metering box 1 have undergone cross-connection. First, under power-off conditions and without disassembling the box, the target phase pair and non-target phases are determined. Then, synchronous, opposite-direction, and equal-amplitude test excitations are applied to the primary conductors of the two phases in the target phase pair, and the secondary circuit responses of the two target current transformers and the non-target current transformers are simultaneously acquired. Based on this, the boundary of the current detection cycle is established using the residual response constraint of the non-target current transformer. Then, the cross-connection determination is completed by matching the actual response polarity of the two target current transformers on the fixed channel with the preset reverse response signature. Further reverse verification and consistency comparison can be used to form the final detection conclusion. Thus, the aforementioned steps, parameter relationships, channel relationships, and system execution relationships together constitute the complete detection process in this embodiment.

[0223] It should be noted that the test stimulus generation method, response amplitude extraction method, signed response quantity extraction method, residual response threshold formation method, relative position parameter definition method, reverse response signature storage method, and reverse verification output method in the above embodiments can all be adapted or equivalently replaced without departing from the technical concept of this application; any implementation method that uses the same or similar technical ideas to detect adjacent double-interchange through-holes inside the fixed box-type three-phase metering box 1 should fall within the protection scope of this application.

Claims

1. A method for detecting adjacent double current transformers in a three-phase metering box, executed by a detection system (2), the detection system (2) being used to detect the three-phase metering box (1), the three-phase metering box (1) being a fixed box type, with three current transformers arranged in a fixed manner inside; characterized in that, After the external terminals of the three-phase metering box (1) are correctly wired and the power-off continuity test is passed, the specific steps of the testing method include: S1. Without unpacking, select two adjacent phases to be checked and establish them as target phase pairs. The target phase pairs include the primary conductor of the first phase and the corresponding first target current transformer, the primary conductor of the second phase and the corresponding second target current transformer, and establish the remaining primary conductor of the first phase and the corresponding current transformer as non-target phase primary conductors and non-target current transformers respectively. S2. Apply a first-direction test excitation to the first-phase primary conductor, and simultaneously apply a second-direction test excitation to the second-phase primary conductor that is opposite to the first-direction test excitation and has the same amplitude, and keep the non-target phase primary conductor without test excitation input during the detection cycle; S3. Synchronously acquire the secondary circuit responses of the first target current transformer and the second target current transformer, as well as the secondary circuit responses of the non-target current transformer; S4. When the secondary circuit response of the non-target current transformer meets the preset residual response restriction condition, the target phase pair is determined to have undergone a crossover based on the matching result of the secondary circuit responses of the first target current transformer and the second target current transformer with the preset reverse response signature.

2. The detection method for adjacent double-phase cross-connection of a three-phase metering box according to claim 1, characterized in that: In step S4, the preset residual response limitation conditions include a residual response threshold set for the secondary circuit response of the non-target current transformer. The residual response threshold is preset or calibrated based on the relative position parameters of the target phase and the primary conductor of the non-target phase in the fixed box type three-phase metering box (1).

3. The detection method for adjacent double-phase cross-connection of a three-phase metering box according to claim 2, characterized in that: The relative position parameters include the center distance between the two primary conductors of the target phase pair, and the geometric distance from the non-target phase primary conductor to the target phase pair; The residual response threshold is configured with both absolute threshold conditions and relative threshold conditions. The relative threshold condition is configured such that the secondary circuit response amplitude of the non-target current transformer is less than a preset proportion of the smaller of the secondary circuit response amplitudes of the first target current transformer and the second target current transformer.

4. The detection method for adjacent double-phase cross-connection of a three-phase metering box according to claim 1, characterized in that: In step S4, based on the matching result of the secondary circuit response of the first target current transformer and the second target current transformer with the preset reverse response signature, it is determined whether the target phase pair has undergone a crossover. Specifically: A first polarity response relationship between the fixed channel of the first target current transformer and the first direction test excitation, and a second polarity response relationship between the fixed channel of the second target current transformer and the second direction test excitation are established in advance. When the actual response polarity extracted from the secondary circuit response of the first target current transformer and the second target current transformer, and its affiliation on the fixed channel of the first target current transformer and the second target current transformer, is reversed relative to the first polarity response relationship and the second polarity response relationship, it is determined that the target phase pair has undergone a cross-connection.

5. The detection method for adjacent double-phase cross-connection of a three-phase metering box according to claim 4, characterized in that: The actual response polarity extracted from the secondary circuit responses of the first and second target current transformers is specifically determined by extracting the signed response quantity of the secondary circuit response within a preset detection window. The signed response quantity is composed of at least one of the integral value of the response waveform within the preset detection window, the phase sign quantity, or the polarity sign quantity. The preset detection window is located within the time overlap interval between the first direction test stimulus and the second direction test stimulus, and excludes the initial transient response interval and the withdrawal transient response interval of the test stimulus.

6. The detection method for adjacent double-phase cross-connection of a three-phase metering box according to claim 1, characterized in that: It also includes a reverse verification step, the specific steps of which are: After completing steps S2 to S4 and obtaining the first determination result, the directions of the test excitation applied to the first phase primary conductor and the second phase primary conductor are simultaneously reversed to execute the second detection cycle. During the second detection cycle, the secondary circuit responses of the first target current transformer, the second target current transformer, and the non-target current transformer are resynchronized and collected. The second determination result is obtained again based on the matching result of the residual response constraint and the reverse response signature. The first determination result is compared with the second determination result for consistency, and the comparison result is used as the basis for the final detection conclusion.

7. The detection method for adjacent double-phase cross-connection of a three-phase metering box according to claim 6, characterized in that: The first determination result is compared with the second determination result for consistency, and the comparison result is used as the basis for the final detection conclusion. Specifically, this includes: When the first determination result is consistent with the second determination result, based on the consistent determination result, a definite conclusion is output that adjacent pairs exchange through the center or the center is correct. When the first determination result is inconsistent with the second determination result, the detection conclusion of abnormal coupling to be reviewed is output.

8. The detection method for adjacent double-phase cross-connection of a three-phase metering box according to claim 1, characterized in that, The first direction test excitation and the second direction test excitation applied in step S2 are generated by the same reference test signal after phase inversion and amplitude balancing, so that the start-up time of the two test excitations applied to the first phase primary conductor and the second phase primary conductor are synchronized, the amplitudes are equal and the directions are opposite.

9. A detection system for adjacent double-phase current transformers in a three-phase metering box, used for detecting a three-phase metering box (1), wherein the three-phase metering box (1) is a fixed box type and has three current transformers arranged in a fixed manner inside; characterized in that: The detection system includes: The processing control unit (23) is used to select two adjacent phases to be checked as target phase pairs without opening the box after the wiring of the external terminals of the three-phase metering box (1) is correct and the power failure continuity test is passed. The target phase pairs include the first phase primary conductor and the corresponding first target current transformer, the second phase primary conductor and the corresponding second target current transformer, and the remaining one phase primary conductor and the corresponding current transformer are respectively established as non-target phase primary conductor and non-target current transformer. The excitation unit (21) is used to apply a first-direction test excitation to the first phase primary conductor, and at the same time apply a second-direction test excitation to the second phase primary conductor that is opposite to the first-direction test excitation and has the same amplitude, and keep the non-target phase primary conductor without test excitation input during the detection cycle; The acquisition unit (22) is used to synchronously acquire the secondary circuit response of the first target current transformer and the second target current transformer, as well as the secondary circuit response of the non-target current transformer. The processing control unit (23) is also used to determine whether the target phase pair has undergone a cross-connection when the secondary circuit response of the non-target current transformer meets the preset residual response restriction conditions, based on the matching result of the secondary circuit response of the first target current transformer and the second target current transformer with the preset reverse response signature.

10. 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 detection method for adjacent double mutual cross-passage of the three-phase metering box as described in any one of claims 1 to 8.

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