Mutual inductor detection system based on detection signal injection

Abstract

The invention relates to the technical field of electric power detection, and discloses a mutual inductor detection system based on detection signal injection, which comprises a data acquisition module and an intelligent evaluation module. According to the mutual inductor detection system based on detection signal injection, material specification data, signal detection data and historical maintenance records of all current transformers are acquired through the data acquisition module and are classified to form a data set, the intelligent evaluation module analyzes amplitude errors and angle errors of each current transformer, measurement errors are deeply analyzed, and the detection accuracy of the current transformers is improved. The excitation characteristic of each current transformer is clearly mastered, the intelligent evaluation module analyzes the fault frequency and the quality score of each current transformer, whether the use environment and the load condition of the current transformer are unbalanced or not is judged, and when the total number of times that the measurement error of the current transformer exceeds the standard exceeds an abnormal threshold value, the current transformer is detected. And if the current transformer is not qualified, indicating that the use environment and the load condition of the current transformer are unbalanced, marking the current transformer with the lowest quality score in each batch, and accurately troubleshooting hidden troubles.

Description

Technical Field

[0001] The present invention relates to the technical field of power detection, and specifically to a current transformer detection system based on test signal injection. Background Art

[0002] A current transformer is a device widely used in power systems, mainly for measuring and protecting high-current circuits. The working principle of a current transformer is based on the law of electromagnetic induction. When a high current on the primary side passes through the coil, an induced current will be generated on the secondary side. The magnitude of this induced current is proportional to the primary current and inversely proportional to the number of turns of the secondary coil. The technical specifications of current transformers include accuracy class, rated current, turns ratio, and rated capacity, etc. These parameters determine the performance and applicability of the current transformer. Current transformers are widely used in substations, power plants, industrial and mining enterprises, etc. in power systems to achieve functions such as current measurement, protection, and control. They convert the current value in a high-current circuit into a small current signal that can be received and processed by devices such as meters, protection devices, and recorders. However, in the actual use process, factors such as the core material, core cross-section, and number of turns of the coil of the current transformer will all affect the measurement error. The exciting current is one of the main reasons for the error of the current transformer. The exciting current is the working current required to establish a magnetic field. The exciting current has a different phase from the primary current, resulting in amplitude error and angle error. During normal operation, the exciting impedance is large and the exciting current is small, and the error can be ignored. However, in the saturation state, the exciting impedance becomes small and the exciting current increases, which will make the error larger. The correct selection, configuration, and use of current transformers are crucial for the safe and stable operation of power systems. Through reasonable configuration, accurate measurement and reliable protection of power systems can be ensured.

[0003] Currently, traditional current transformer detection systems based on test signal injection often ignore the angle error caused by the change of the exciting current. This oversight may lead to misoperation or refusal to operate of protection devices, thus threatening the safe and stable operation of power systems. In addition, there is a lack of a unified standard to evaluate the comprehensive quality score of current transformers, and there is a delay in fault detection, making it difficult to detect potential fault hazards in a timely manner. Summary of the Invention

[0004] (1) Technical Problems to be Solved

[0005] Aiming at the deficiencies of the prior art, the present invention provides a current transformer detection system based on test signal injection, which has the advantages of in-depth analysis of measurement errors and accurate investigation of potential fault hazards, and solves the problems that traditional current transformer detection systems based on test signal injection ignore the influence of exciting current changes on angle errors and lack a unified standard to evaluate the comprehensive quality of current transformers.

[0006] (2) Technical Solutions

[0007] To achieve the above object, the present invention provides the following technical solution: A current transformer detection system based on inspection signal injection, comprising a data acquisition module and an intelligent evaluation module;

[0008] The data acquisition module is composed of a material data unit, an inspection data unit, and a historical data unit. The material data unit collects a material data set through a network connection to a database. The material data set includes the material specification data of all current transformers. The inspection data unit collects an inspection data set through a network connection to a current transformer. The inspection data set includes the signal inspection data of all current transformers. The historical data set collects a historical data set through a network connection to a database. The historical data set includes the historical maintenance records of all current transformers. The data acquisition module transmits the material data set, the inspection data set, and the historical data set to the intelligent evaluation module through a network;

[0009] The intelligent evaluation module is composed of an inspection analysis unit, a fault analysis unit, and a scheduling management unit. The inspection analysis unit analyzes the amplitude error Fzwc and the angle error Jdwc of each current transformer according to the material data set and the inspection data set, and transmits them to the scheduling management unit through a network. The fault analysis unit analyzes the fault frequency Gpl of each current transformer according to the material data set and the historical data set, and transmits it to the scheduling management unit through a network. The scheduling management unit sets an evaluation period PZ with a fixed duration, and combines the material data set, the amplitude error Fzwc, the angle error Jdwc, and the fault frequency Gpl to calculate the quality score Zlpc of each current transformer. The scheduling management unit sets an abnormal threshold YY with a fixed range, and then combines the quality score Zlpc to judge whether the usage environment and load conditions of the current transformer are unbalanced, and outputs the corresponding judgment result.

[0010] Preferably, the expression of the material data set is {Q1 d 、Q2 d 、Q3 d 、...、Qm d}, where Q1 d to Qm d are respectively the material specification data of the first to the mth batch of current transformers. The material specification data includes the number of primary turns, the number of secondary turns, and the accuracy class. d represents the specific time when a single batch of current transformers starts to be put into use. In a single batch, the material specification data and the specific time of putting into use of all current transformers are the same.

[0011] Preferably, the expression of the detection data set is to They are the signal inspection data of the first to the nth current transformers respectively. b represents the current value input to the primary side of the current transformer, and c represents the current value output from the secondary side of the current transformer.

[0012] Preferably, the expression of the historical data set is {L1 s , L2 s , L3 s ,..., Ln s}, where L1 s to Ln s are the historical maintenance records of the first to the nth current transformers respectively. The historical maintenance records include the cause of failure and the historical replacement parts, and s represents the total number of historical maintenance of a single current transformer.

[0013] Preferably, the calculation process of the amplitude error Fzwc is as follows:

[0014] Extract the material specification data of the current transformers in the i-th batch from the material data set, and mark the number of turns on the primary side of the i-th batch of current transformers as YC i , mark the number of turns on the secondary side of the i-th batch of current transformers as EC i , and mark the accuracy class of the i-th batch of current transformers as ZQ i ;

[0015] According to the inspection data set, extract the signal inspection data of the k-th current transformer in the i-th batch. Among them, Jk b represents the standard current value input to the primary side of the k-th current transformer, and Jk c represents the actual current value output from the secondary side of the k-th current transformer;

[0016]

[0017] In the formula, Fzwc represents the amplitude error, represents the ratio of the number of turns on the primary side to the number of turns on the secondary side of the current transformer in the i-th batch, that is, the transformation ratio CT of the k-th current transformer k , represents dividing the standard current value on the primary side by the transformation ratio to obtain the predicted value IY of the current output from the secondary side of the k-th current transformer k , IY k - Jk c represents the difference between the predicted value of the current output from the secondary side and the actual current value, represents the ratio of the current difference of the k-th current transformer to the predicted value of the current output from the secondary side, and the amplitude error is expressed in percentage.

[0018] Preferably, the calculation process of the angle error Jdwc is as follows:

[0019] According to the signal test data of the k-th current transformer, use a phase meter to measure the phase angles of the primary-side current waveform and the secondary-side current waveform, and mark the phase angle of the primary-side current waveform as X y , and mark the phase angle of the secondary-side current waveform as X y ;

[0020] Jdwc = sin(X y + X e ) - sin(X y - X e )

[0021] In the formula, Jdwc represents the angle error, and sin(X y + X e ) - sin(X y - X e ) represents that according to the sum-to-product formula, the calculated angular difference is the angle error of the k-th current transformer.

[0022] Preferably, the calculation process of the fault frequency Gpl is as follows:

[0023] According to the historical data set, extract the historical maintenance records of the k-th current transformer in the i-th batch, and mark the total number of historical maintenance of the k-th current transformer as k s ;

[0024]

[0025] In the formula, Gpl represents the fault frequency, DQ represents the current time point, and k d represents the specific time when the k-th current transformer starts to be put into use, and DQ - k d represents the total service life of the k-th current transformer put into use, represents the total number of historical maintenance divided by the total service life put into use, which is the fault frequency of the k-th current transformer.

[0026] Preferably, the calculation process of the quality score Zlpc is as follows:

[0027] According to the accuracy level ZQ of the current transformers in the i-th batch i , set the corresponding amplitude threshold FY and angular difference threshold JY, compare the amplitude error Fzwc of the k-th current transformer in the i-th batch with the amplitude threshold FY, and compare the angle error Jdwc of the k-th current transformer in the i-th batch with the angular difference threshold JY;

[0028] During the statistical evaluation period PZ, count the number of times the amplitude error Fzwc of the k-th current transformer exceeds the amplitude threshold FY, and mark it as FS;

[0029] During the statistical evaluation period PZ, count the number of times the angular error Jdwc of the k-th current transformer exceeds the angular difference threshold JY, and mark it as JS;

[0030]

[0031] In the formula, Zlpc represents the quality score, represents the average value of the quality scores of the current transformers in the i-th batch, FS + JS represents the total number of times the measurement error of the k-th current transformer exceeds the standard, α represents the weight for the number of times the error exceeds the standard, β represents the weight for the failure frequency, both α and β are constants, and α + β = 1, α(FS + JS)+βGpl represents converting the total number of times the measurement error of the k-th current transformer exceeds the standard and the failure frequency into defect scores according to the weights of α and β, represents subtracting the defect score of the k-th current transformer from the average value of the quality scores of the same batch to obtain the quality score of the k-th current transformer.

[0032] Preferably, when the total number of times the measurement error of the current transformer exceeds the standard exceeds the abnormal threshold YY, it indicates that the usage environment and load conditions of the current transformer are out of balance. Extract the historical maintenance records of the current transformer from the historical dataset and generate an abnormal alarm to remind the management staff to perform calibration processing.

[0033] Preferably, the scheduling management unit arranges the current transformers of the same batch in descending order according to the quality score Zlpc, marks the current transformer ranked last in each batch, and forms a replacement list to remind the management staff to replace the current transformer in a timely manner.

[0034] Compared with the prior art, the present invention provides a current transformer detection system based on inspection signal injection, which has the following beneficial effects:

[0035] 1. The present invention connects the database and the current transformer through the data acquisition module network, obtains the material specification data, signal inspection data, and historical maintenance records of all current transformers, classifies and forms a material dataset, an inspection dataset, and a historical dataset. The intelligent evaluation module analyzes the amplitude error Fzwc and angular error Jdwc of each current transformer according to the material dataset and the inspection dataset, accurately calculates the error of each current transformer during the current conversion process, deeply analyzes the measurement error, clearly masters the excitation characteristics of each current transformer, can better match and adjust the current transformer, ensure its stable operation under various load conditions, and optimize the overall performance of the power system.

[0036] 2. According to the material data set and the historical data set, the intelligent evaluation module of the present invention analyzes the failure frequency Gpl and the quality score Zlpc of each current transformer, and judges whether the usage environment and load conditions of the current transformer are out of balance. When the total number of times that the measurement error of the current transformer exceeds the standard exceeds the abnormal threshold YY, it indicates that the usage environment and load conditions of the current transformer are out of balance. The historical maintenance records of the current transformer in the historical data set are extracted, and an abnormal alarm is generated to remind the management personnel to perform calibration processing. The dispatching management unit arranges the current transformers of the same batch according to the quality score Zlpc from high to low, marks the current transformer ranked last in each batch arrangement, and forms a replacement list to remind the management personnel to replace the current transformer in time and accurately detect potential fault hazards. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is a schematic diagram of the system flow of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0038] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0039] Since the traditional current transformer detection system based on test signal injection often ignores the angular error caused by the change of exciting current, this neglect may lead to misoperation or refusal of the protection device, thereby threatening the safe and stable operation of the power system. In addition, there is a lack of a unified standard to evaluate the comprehensive quality score of current transformers, and there is a delay in fault detection, making it difficult to detect potential fault hazards in a timely manner. Therefore, a current transformer detection system based on test signal injection is provided. Please refer to Figure 1 , the system includes a data acquisition module and an intelligent evaluation module;

[0040] The data acquisition module consists of a material data unit, a test data unit, and a historical data unit. The material data unit collects the material data set through the network connection to the database. The material data set includes the material specification data of all current transformers. The expression of the material data set is {Q1 d , Q2 d , Q3 d ,..., Qm d}, Q1 d to Qm dThey are the material specification data of the first to the mth batch current transformers respectively. The material specification data includes the number of primary turns, the number of secondary turns and the accuracy class. The accuracy class includes levels such as 0.2, 0.5, 1, 3, 5. Among them, the 0.2 level is the highest accuracy, and the current value error range is usually +0.2%. d represents the specific time when a single batch of current transformers starts to be put into use. In a single batch, the material specification data and the specific time of putting into use of all current transformers are the same. The current transformers are classified by batch to facilitate the subsequent rapid identification and detection of equipment that may have potential fault hazards in the same batch;

[0041] The inspection data unit collects the inspection data set by connecting to the current transformer through the network. The inspection data set includes the signal inspection data of all current transformers. The expression of the detection data set is to They are the signal inspection data of the first to the nth current transformers respectively. b represents the current value input to the primary side of the current transformer, and c represents the current value output from the secondary side of the current transformer. Real-time monitoring of the output feedback generated by the current transformer for the input inspection signal is the key basis for subsequent judgment of whether the error exceeds the standard;

[0042] The historical data set collects the historical data set by connecting to the database through the network. The historical data set includes the historical maintenance records of all current transformers. The expression of the historical data set is {L1 s 、L2 s 、L3 s 、...、Ln s}, L1 s to Ln s They are the historical maintenance records of the first to the nth current transformers respectively. The historical maintenance record includes the cause of the fault and the historical replacement parts. s represents the total number of historical repairs of a single current transformer. Detailed recording of the historical repair process of each current transformer helps the management personnel to quickly handle potential fault hazards and ensure the safe and stable operation of the power system;

[0043] The data acquisition module transmits the material data set, the inspection data set and the historical data set to the intelligent evaluation module through the network;

[0044] The intelligent evaluation module consists of an inspection analysis unit, a fault analysis unit and a scheduling management unit. The inspection analysis unit analyzes the amplitude error Fzwc and the angle error Jdwc of each current transformer according to the material data set and the inspection data set, and transmits them to the scheduling management unit through the network. The calculation process is as follows:

[0045] Extract the material specification data of the ith batch current transformer in the material data set, and mark the number of primary turns of the ith batch current transformer as YCi Mark the number of secondary turns of the i-th batch current transformer as EC i Mark the accuracy class of the i-th batch current transformer as ZQi;

[0046] According to the test data set, extract the signal test data of the k-th current transformer in the i-th batch, where Kk b represents the standard current value input to the primary side of the k-th current transformer, and Jk c represents the actual current value output from the secondary side of the k-th current transformer;

[0047]

[0048] In the formula, Fzwc represents the amplitude error, represents the ratio of the number of primary turns to the number of secondary turns of the i-th batch current transformer, which is the transformation ratio CTk of the k-th current transformer, represents dividing the primary side standard current value by the transformation ratio to obtain the estimated value IY of the current output from the secondary side of the k-th current transformer k , IY k -Jk c represents the difference between the estimated value of the secondary side output current and the actual current value, represents the ratio of the current difference of the k-th current transformer to the estimated value of the secondary side output current. The amplitude error is expressed as a percentage, and the error of each current transformer during the current conversion process is accurately calculated;

[0049] According to the signal test data of the k-th current transformer, use a phase meter to measure the phase angles of the primary side current waveform and the secondary side current waveform, and mark the phase angle of the primary side current waveform as X y , mark the phase angle of the secondary side current waveform as X y ;

[0050] Jdwc = sin(X y +X e ) - sin(X y -X e )

[0051] In the formula, Jdwc represents the angle error, and sin(X y +X e ) - sin(X y -X e ) represents that according to the sum-to-product formula, the calculated angular difference is the angle error of the k-th current transformer. By deeply analyzing the measurement error and clearly mastering the excitation characteristics of each current transformer, the current transformer can be better matched and adjusted to ensure its stable operation under various load conditions and optimize the overall performance of the power system;

[0052] The fault analysis unit analyzes the fault frequency Gpl of each current transformer according to the material data set and the historical data set, and transmits it to the dispatching management unit through the network. The calculation process is as follows:

[0053] Extract the historical maintenance records of the k-th current transformer in the i-th batch according to the historical data set, and mark the total number of historical maintenance of the k-th current transformer as k s ;

[0054]

[0055] In the formula, Gpl represents the fault frequency, DQ represents the current time point, and k d represents the specific time when the k-th current transformer starts to be put into use, and DQ - k d represents the total duration of the k-th current transformer in use, represents the total number of historical maintenance divided by the total duration of use, that is, the fault frequency of the k-th current transformer;

[0056] The dispatching management unit sets an evaluation period PZ with a fixed duration, and combines the material data set, amplitude error Fzwc, angle error Jdwc and fault frequency Gpl to calculate the quality score Zlpc of each current transformer. The calculation process is as follows:

[0057] According to the accuracy level ZQ of the current transformers in the i-th batch i , set the corresponding amplitude threshold FY and angular difference threshold JY, and compare the amplitude error Fzwc of the k-th current transformer in the i-th batch with the amplitude threshold FY, and compare the angle error Jdwc of the k-th current transformer in the i-th batch with the angular difference threshold JY;

[0058] Count the number of times the amplitude error Fzwc of the k-th current transformer exceeds the amplitude threshold FY during the evaluation period PZ, and mark it as FS;

[0059] Count the number of times the angle error Jdwc of the k-th current transformer exceeds the angular difference threshold JY during the evaluation period PZ, and mark it as JS;

[0060]

[0061] In the formula, Zlpc represents the quality score, denotes the average value of the quality scores of the \(i\)-th batch of current transformers. \(FS + JS\) represents the total number of times the measurement error of the \(k\)-th current transformer exceeds the standard. \(\alpha\) represents the weight for the number of times the error exceeds the standard, and \(\beta\) represents the weight for the failure frequency. Both \(\alpha\) and \(\beta\) are constants, and \(\alpha+\beta = 1\). \(\alpha(FS + JS)+\beta G_{pl}\) represents converting the total number of times the measurement error of the \(k\)-th current transformer exceeds the standard and the failure frequency into defect scores according to the weights of \(\alpha\) and \(\beta\). It means subtracting the defect score of the \(k\)-th current transformer from the average value of the quality scores of the same batch to obtain the quality score of the \(k\)-th current transformer. When the average value of the quality scores of this batch of current transformers has not been calculated yet, the average value of the quality scores of another batch of current transformers with similar material specifications and service life can be selected as the base score.

[0062] The dispatching management unit is set with an abnormal threshold \(YY\) within a fixed range. Combining with the quality score \(Zl_{pc}\), it judges whether the operating environment and load conditions of the current transformer are out of balance. When the total number of times the measurement error of the current transformer exceeds the standard exceeds the abnormal threshold \(YY\), it indicates that the operating environment and load conditions of this current transformer are out of balance. The historical maintenance records of this current transformer in the historical dataset are extracted, and an abnormal alarm is generated to remind the management staff to perform calibration processing. The dispatching management unit arranges the current transformers of the same batch in descending order according to the quality score \(Zl_{pc}\), marks the current transformer ranked last in each batch, and forms a replacement list to remind the management staff to replace the current transformer in time and accurately check for potential faults.

[0063] Example 1: In this experiment, a current transformer with 200 turns on the primary side and 5 turns on the secondary side is selected as the experimental object. After inputting a current of 100 A into the primary side of this current transformer, the actual current value detected at the secondary side output is 2 A. The calculation formula for the amplitude error \(F_{zwc}\) of this current transformer is as follows:

[0064]

[0065] In the formula, \(F_{zwc}\) represents the amplitude error. represents the ratio of the number of turns on the primary side to the number of turns on the secondary side of the current transformer, and 40 is the transformation ratio \(CT\) of this current transformer. k , represents dividing the standard current value on the primary side by the transformation ratio to obtain the estimated value \(I_Y\) of the current output on the secondary side of the current transformer. k is 2.5 A, and 20% represents the ratio of the current difference of this current transformer to the estimated value of the current output on the secondary side. The amplitude error is expressed as a percentage.

[0066] Example 2: In this experiment, current transformers with an average quality score of 90 in the same batch were selected as the experimental objects. After statistics, within one hour, the number of times the amplitude error Fzwc of the current transformer exceeded the amplitude threshold FY was 5 times, and the number of times the angular error Jdwc exceeded the angular difference threshold JY was 2 times. The failure frequency of the current transformer after being put into use was 1 time per month. The calculation formula for the quality score Zlpc of the current transformer is as follows:

[0067]

[0068] In the formula, Zlpc represents the quality score, 90 represents the average quality score of this batch of current transformers, 5 + 2 represents the total number of times the measurement error of the current transformer exceeds the standard, 0.4 represents the weight for the number of times the error exceeds the standard, 0.6 represents the weight for the failure frequency, both α and β are constants, and 0.4 + 0.6 = 1. 0.4(5 + 2) + 0.6×1 represents converting the total number of times the measurement error of the current transformer exceeds the standard and the failure frequency into defect scores according to the weights of α and β. 90 - [0.4(5 + 2) + 0.6×1] represents subtracting the defect score of the current transformer from the average quality score of the same batch. The quality score of this current transformer is 86.6.

[0069] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A transformer detection system based on test signal injection, characterized in that: Including data acquisition module and intelligent evaluation module; The data acquisition module is composed of a material data unit, a test data unit and a history data unit. The material data unit is connected to a database through a network to collect a material data set, and the material data set includes material specification data of all current transformers. The test data unit is connected to a current transformer through a network to collect a test data set, and the test data set includes signal test data of all current transformers. The history data set is connected to a database through a network to collect a history data set, and the history data set includes historical maintenance records of all current transformers. The data acquisition module transmits the material data set, the test data set and the history data set to the intelligent evaluation module through the network. The intelligent evaluation module is composed of an inspection and analysis unit, a fault analysis unit and a scheduling management unit. The inspection and analysis unit analyzes the amplitude error Fzwc and the angle error Jdwc of each current transformer according to the material data set and the inspection data set, and transmits them to the scheduling management unit through the network. The fault analysis unit analyzes the fault frequency Gpl of each current transformer according to the material data set and the historical data set, and transmits them to the scheduling management unit through the network. The scheduling management unit is provided with an evaluation period PZ of a fixed duration, and calculates the quality score Zlpc of each current transformer in combination with the material data set, the amplitude error Fzwc, the angle error Jdwc and the fault frequency Gpl. The scheduling management unit is provided with an abnormal threshold value YY in a fixed range, and then combined with the quality score Zlpc, determines whether the use environment and load conditions of the current transformer are unbalanced, and outputs the corresponding judgment result.

2. A mutual inductor detection system based on test signal injection according to claim 1, characterized in that: The expression of the material data set is {Q1 d 、Q2 d 、Q3 d , ..., Qm d }, Q1 d To Qm d They are the material specification data of the first to mth batches of current transformers, respectively. The material specification data include the primary side turns, the secondary side turns and the accuracy grade. d represents the specific time when a single batch of current transformers begins to be put into use. In a single batch, the material specification data and the specific time of being put into use of all current transformers are the same.

3. A mutual inductor detection system based on test signal injection according to claim 2, characterized in that: The expression of the detection data set is: to They are the signal inspection data of the first to nth current transformers respectively, b represents the current value input to the primary side of the current transformer, and c represents the current value output from the secondary side of the current transformer.

4. The mutual inductor detection system based on test signal injection according to claim 3, characterized in that: The expression of the historical data set is {L1 s 、L2 s 、L3 s , ..., Ln s }, L1 s To Ln s They are the historical maintenance records of the first to the mth current transformers, respectively. The historical maintenance records include the causes of failures and historical replacement parts. s represents the total number of historical maintenance times of a single current transformer.

5. A mutual inductor detection system based on test signal injection according to claim 4, characterized in that: The calculation process of the amplitude error Fzwc is as follows: Extract the material specification data of the i-th batch of current transformers in the material data set, and mark the primary side turns of the i-th batch of current transformers as YC i , mark the secondary turns of the i-th batch of current transformers as EC i , mark the accuracy level of the i-th batch of current transformers as ZQ i ; According to the inspection data set, the signal inspection data of the kth current transformer in the i-th batch is extracted, where Jk b Indicates the standard current value of the primary side of the kth current transformer, Jk c Indicates the actual current value output by the secondary side of the kth current transformer; In the formula, Fzwc represents the amplitude error, It represents the ratio of the primary side turns to the secondary side turns of the i-th batch of current transformers, that is, the transformation ratio CT of the k-th current transformer k , The standard current value on the primary side is divided by the transformation ratio to obtain the estimated value IY of the secondary output current of the kth current transformer. k , IY k -Jk c Indicates the difference between the estimated value and the actual current value of the secondary side output current. It represents the ratio of the kth current transformer current difference to the estimated secondary output current. The amplitude error is expressed as a percentage.

6. A mutual inductor detection system based on test signal injection according to claim 5, characterized in that: The calculation process of the angle error Jdwc is as follows: According to the signal inspection data of the kth current transformer, use the phase meter to measure the phase angle of the primary current waveform and the secondary current waveform, and mark the phase angle of the primary current waveform as X. y , mark the phase angle of the secondary current waveform as X y ; Jdwc=sin(X y +X e )-sin(X y -X e ) In the formula, Jdwc represents the angle error, sin(X y +X e )-sin(X y -X e ) indicates that the angle difference calculated according to the sum-differentiation-product formula is the angle error of the kth current transformer.

7. A mutual inductor detection system based on test signal injection according to claim 6, characterized in that: The fault frequency Gpl calculation process is as follows: According to the historical data set, extract the historical maintenance record of the kth current transformer in the i-th batch, and mark the total number of historical maintenance of the kth current transformer as k s ; In the formula, Gpl represents the fault frequency, DQ represents the current time point, and k d Indicates the specific time when the kth current transformer is put into use, DQ-k d represents the total time that the kth current transformer is put into use, The total number of historical maintenance times divided by the total time in use is the fault frequency of the kth current transformer.

8. The mutual inductor detection system based on test signal injection according to claim 7, characterized in that: The quality score Zlpc calculation process is as follows: According to the accuracy level ZQ of the i-th batch of current transformers i , set the corresponding amplitude threshold FY and angle difference threshold JY, and compare the amplitude error Fzwc of the k-th current transformer in the i-th batch with the amplitude threshold FY, and compare the angle error Jdwc of the k-th current transformer in the i-th batch with the angle difference threshold JY; The number of times the amplitude error Fzwc of the kth current transformer exceeds the amplitude threshold FY during the evaluation period PZ is counted and marked as FS; During the evaluation period PZ, the number of times the angle error Jdwc of the kth current transformer exceeds the angle difference threshold JY is counted and marked as JS; In the formula, Zlpc represents the quality score, represents the average quality score of the i-th batch of current transformers, FS+JS represents the total number of times the k-th current transformer measurement error exceeds the standard, α represents the weight for the number of times the error exceeds the standard, β represents the weight for the fault frequency, α and β are both constants, and α+β=1, α(FS+JS)+βGpl represents the conversion of the total number of times the k-th current transformer measurement error exceeds the standard and the fault frequency into a defect score according to the α and β weights, It means that the defect score of the k-th current transformer is subtracted from the average quality score of the same batch to obtain the quality score of the k-th current transformer.

9. A mutual inductor detection system based on test signal injection according to claim 8, characterized in that: When the total number of times the current transformer measurement error exceeds the abnormal threshold YY, it indicates that the use environment and load conditions of the current transformer are unbalanced, the historical maintenance record of the current transformer in the historical data set is extracted, and an abnormal alarm is generated to remind the management personnel to perform calibration.

10. A mutual inductor detection system based on test signal injection according to claim 9, characterized in that: The dispatch management unit arranges the current transformers of the same batch from high to low according to the quality score Zlpc, marks the last current transformer in each batch, and forms a replacement list to remind the management personnel to replace the current transformers in time.

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