Operation test system and method for high-precision packaged current transformer

Abstract

The invention provides an operation test system and method for a high-precision packaged current transformer, and relates to the technical field of current transformer testing, and the method comprises the steps: collecting the operation state data of the high-precision packaged current transformer in the operation process; according to the step response trend and the loop disturbance gauge when the current is switched in the corresponding measuring range, generating directional current injection excitation during the operation test of the current transformer; performing deviation splicing on the recessive failure sites to obtain a manifold dielectric loss index when the current transformer is subjected to steady-state modulation calibration in an actual working condition, and determining an equivalent frequency response strategy when the current transformer is operated and tested according to the manifold dielectric loss index; and carrying out differential test on the operation transition characteristic of the loop of the current transformer in the current operation state according to the directional injection excitation and equivalent frequency response strategy. According to the application, the hidden fault can be accurately excited in the actual operation condition, and the whole-process state verification is carried out on the current transformer, so that the accuracy of the operation test of the current transformer is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of current transformer testing, and more particularly to a high-precision packaged current transformer operation test system and method. BACKGROUND

[0002] Current transformer testing refers to a technical process of systematically verifying the precision, stability and reliability of a current transformer in an operating state. The process involves data acquisition, working condition simulation, fault diagnosis and performance verification, etc., and involves multiple requirements such as electrical parameter measurement, dynamic response analysis, and insulation performance evaluation. Since high-precision packaged current transformers are in complex working conditions for a long time, the testing accuracy directly affects the accuracy of power grid metering, the reliability of equipment protection, and even the safety of the system. If the testing is insufficient, it may lead to hidden fault detection, measurement deviation or insulation failure. Therefore, building a testing method close to actual working conditions is a key technical foundation for ensuring the stable operation of the power system.

[0003] However, existing high-precision packaged current transformer operation test methods mostly rely on single electrical parameter detection under standard static working conditions, and only focus on the steady-state precision performance under rated conditions, which makes the testing process seriously disconnected from the actual dynamic operating conditions, resulting in the inability to effectively reproduce the transient response characteristics under real scenarios such as load mutation and range switching. Hidden hidden failure sites are difficult to be triggered and captured, thereby affecting the reliability of the test results. Therefore, how to accurately trigger hidden faults in actual operating conditions and perform full-process state verification on the current transformer to improve the accuracy of current transformer operation testing is a technical problem currently faced. SUMMARY

[0004] The present application provides a high-precision packaged current transformer operation test system and method, which can accurately trigger hidden faults in actual operating conditions and perform full-process state verification on the current transformer to improve the accuracy of current transformer operation testing.

[0005] In a first aspect, the present application provides a high-precision packaged current transformer operation test method, which includes the following steps: Acquiring operating state data of a high-precision packaged current transformer during operation; Resetting the operating state data in a closed loop to obtain step response trends of the current transformer under different load modes, and generating directional current injection excitation for current transformer operation testing according to the step response trends and loop disturbance limits of the current when switching corresponding ranges. Determine the implicit failure site of the current transformer under the disturbance working condition, bias splice the implicit failure site, obtain the manifold dielectric loss index of the current transformer in the actual working condition for steady-state modulation calibration, and then determine the equivalent frequency response strategy of the current transformer in the running test from the manifold dielectric loss index; According to the directional injection flow excitation and the equivalent frequency response strategy, the differential test is performed on the running transition characteristics of the current transformer loop in the current running state.

[0006] In this embodiment, the running state data is closed-loop reset to obtain the step response trend of the current transformer under different load modes, which specifically includes: According to the running state data, determine the current jump constraint of the current transformer under different load modes; All current jump constraints are fed back and reorganized to obtain the step response identification under different load modes; According to all step response identifications, determine the step response trend of the current transformer under different load modes.

[0007] In this embodiment, the step response trend refers to the law of the response characteristics of the current transformer changing with the load.

[0008] In this embodiment, the directional injection flow excitation refers to the current signal injected by the current transformer in the running working condition test of different ranges.

[0009] In this embodiment, determining the implicit failure site of the current transformer under the disturbance working condition specifically includes: Obtain the multi-modal monitoring data of the current transformer under multiple disturbance working conditions; All multi-modal monitoring data are fused to obtain the failure hetero-degree attribute of the current transformer under the disturbance working condition; According to the failure hetero-degree attribute, determine the implicit failure site of the current transformer under the disturbance working condition.

[0010] In this embodiment, the implicit failure site refers to the potential fault position of the current transformer under the disturbance working condition, which is difficult to be found by conventional testing and will affect the running accuracy.

[0011] In this embodiment, determining the equivalent frequency response strategy of the current transformer in the running test from the manifold dielectric loss index specifically includes: According to the manifold dielectric loss index, determine the switching adaptation gradient of the current transformer in the working condition switching operation; According to the switching adaptation gradient, determine the guide frequency response track of the current transformer in the running test; Determine the equivalent frequency response strategy of the current transformer in the running test from the guide frequency response track.

[0012] In the embodiment, the steady-state modulation calibration refers to a process that the current transformer outputs in accordance with the precision standard when adjusting the operation parameters under various steady-state working conditions.

[0013] In the embodiment, the operation transition characteristic refers to a dynamic change characteristic of the loop current of the current transformer when the working condition is switched from one steady state to another steady state.

[0014] In a second aspect, the application provides a high-precision packaged current transformer operation test system for executing a high-precision packaged current transformer operation test method, and the operation test system comprises: a data acquisition module configured to acquire operation state data of the high-precision packaged current transformer during operation; a closed-loop reset module configured to perform closed-loop reset on the operation state data to obtain a step response trend of the current transformer under different load modes, and generate a directional current injection excitation for the current transformer operation test according to the step response trend and a loop disturbance limit when the current is switched in the corresponding range; a deviation splicing module configured to determine an implicit failure site of the current transformer under a disturbance working condition, perform deviation splicing on the implicit failure site, obtain a manifold dielectric loss index of the current transformer when performing steady-state modulation calibration in an actual working condition, and further determine an equivalent frequency response strategy of the current transformer during the operation test according to the manifold dielectric loss index; a differential test module configured to perform differential test on the operation transition characteristic of the loop of the current transformer in the current operation state according to the directional current injection excitation and the equivalent frequency response strategy.

[0015] The technical scheme provided by the embodiments disclosed in the application has the following beneficial effects: By acquiring the operation state data of the high-precision packaged current transformer during operation, performing closed-loop reset on the operation state data to obtain a step response trend of the current transformer under different load modes, generating a directional current injection excitation for the current transformer operation test according to the step response trend and a loop disturbance limit when the current is switched in the corresponding range, determining an implicit failure site of the current transformer under a disturbance working condition, performing deviation splicing on the implicit failure site, obtaining a manifold dielectric loss index of the current transformer when performing steady-state modulation calibration in an actual working condition, and further determining an equivalent frequency response strategy of the current transformer during the operation test according to the manifold dielectric loss index, differential test is performed on the operation transition characteristic of the loop of the current transformer in the current operation state according to the directional current injection excitation and the equivalent frequency response strategy.

[0016] It can be seen that in the present application, the comprehensiveness and accuracy of the operation test can be improved under the defects of the existing current transformer test method, such as static working condition detection, dynamic response and lack of correlation of hidden faults. Among them, by collecting the running state data of high-precision packaged current transformers in the running process, real and full-scene working condition reference data can be provided for testing, avoiding the deviation between traditional laboratory static testing and field dynamic operation, and ensuring the accuracy and representativeness of the test basic data. By resetting the running state data in a closed loop and generating a directional flow excitation, real load mutation and range switching scenarios can be simulated, the dynamic response characteristics under actual working conditions can be reproduced, the problem of disconnection between traditional excitation signals and actual operation can be solved, and the authenticity and safety of the test input can be significantly improved. By determining the hidden failure site and calculating the flow form dielectric loss index, the hidden faults such as insulation deterioration and poor contact that cannot be found by conventional testing can be accurately located, and the influence degree can be quantified, avoiding the operation risk caused by fault omission, and providing accurate basis for test strategy formulation. By differential testing of directional flow excitation and equivalent frequency response strategy, the transition characteristics of the loop under dynamic working conditions and key frequencies can be verified comprehensively, the correlation evaluation of process dynamic response and result static precision can be realized, and the reliability of the test can be significantly improved.

[0017] In summary, the technical scheme adopted by the present application can accurately excite hidden faults in actual running conditions and verify the current transformer in the whole process to improve the accuracy of the current transformer operation test. BRIEF DESCRIPTION OF DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or prior art description will be briefly introduced. Obviously, the drawings in the following description are only the embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0019] Figure 1 is an exemplary flowchart of a high-precision packaged current transformer operation test method according to the present application; Figure 2 is a flowchart of determining a directional flow excitation according to the present application; Figure 3 is a flowchart of determining a flow form dielectric loss index according to the present application; Figure 4 is a module structure diagram of a high-precision packaged current transformer operation test system according to the present application. DETAILED DESCRIPTION

[0020] With reference to the accompanying drawings, the technical solutions in the embodiments of the present application will be described clearly and completely. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without creative work fall within the scope of the present application.

[0021] The embodiments of the present application provide a running test system and method for a high-precision packaged current transformer, the core of which is to collect running state data of the high-precision packaged current transformer in a running process; to perform closed-loop resetting on the running state data to obtain a step response trend of the current transformer under different load modes, to generate a directional injection excitation for the current transformer in a running test according to the step response trend and a loop disturbance limit when the current is switched in a corresponding range; to determine an implicit failure site of the current transformer under a disturbance working condition, to perform deviation splicing on the implicit failure site to obtain a flow form dielectric loss index of the current transformer in a steady-state modulation calibration in an actual working condition, and to further determine an equivalent frequency response strategy of the current transformer in the running test from the flow form dielectric loss index; and to perform differential test on a running transition characteristic of a loop of the current transformer in a current running state according to the directional injection excitation and the equivalent frequency response strategy.

[0022] Embodiment one, in order to better understand the above technical solutions, the above technical solutions will be described in detail below in combination with the description of the drawings and specific embodiments. Referring to FIG. 1, Figure 1 The figure is an exemplary flow chart of a running test method for a high-precision packaged current transformer according to the embodiments of the present application, the running test method comprising the following steps: In step S1, running state data of the high-precision packaged current transformer in a running process is collected.

[0023] In a specific implementation, a 0.05-grade high-precision current sensor can be selected to be connected in series between the primary side and the secondary side loop of the transformer, to collect the primary side input current and the secondary side output current in real time; a ±0.1℃ precision temperature sensor can be pasted on the inner wall and the outer wall of the transformer package respectively, to synchronously collect the internal core component temperature and the external environment temperature; a high-frequency vibration sensor (sampling frequency 1 kHz) can be fixed on the transformer shell, to capture the vibration signal in operation; and a voltage monitoring module can be connected to collect the voltage fluctuation data of the primary side and the secondary side loop. Two core scenarios are covered in the collection: in a steady state scenario, a rated load (such as 100% rated current) is maintained for continuous collection for 24 hours, and a group of data is recorded every 10 seconds; in a dynamic scenario, the process of simulating a load to suddenly increase from 20% rated value to 120% rated value and switching the range from 100A to 500A is simulated, and a group of transient data is recorded every 1 millisecond. After collection, abnormal data is removed by the “3σ criterion”, and the data after removal of abnormal data is used as the operating state data of the high-precision packaged current transformer in the operation process, which is not described here.

[0024] It should be noted that in this application, the operating state data represents the multi-dimensional parameters of the operating characteristics of the high-precision packaged current transformer.

[0025] In step S2, the operating state data is closed-loop reset to obtain the step response trend of the current transformer under different load modes, and the directional injection excitation during the operation test of the current transformer is generated according to the step response trend and the loop disturbance limit when the current is switched in the corresponding range.

[0026] In this embodiment, the step response trend of the current transformer under different load modes can be obtained by resetting the operating state data in a closed loop, which can be realized by the following steps: According to the operating state data, the current jump constraints of the current transformer under different load modes are determined; All current jump constraints are fed back and reorganized to obtain the step response identifiers under different load modes; According to all the step response identifiers, the step response trend of the current transformer under different load modes is determined.

[0027] In a specific implementation, first, the data set corresponding to different load modes is filtered from the running state data, and is classified according to light load (20% to 50% rated load), full load (80% to 100% rated load), and overload (105% to 120% rated load). For the current data of each load mode, the 95% percentile method is used for statistics: the maximum and minimum values of the instantaneous change of the current in this mode are calculated, and then combined with the rated current parameters of the transformer (for example, if the rated current is 100 A, then the maximum jump of the overload should not exceed 20 A), to determine the maximum jump amplitude, minimum jump amplitude, and lower limit of the jump time of the current from the initial value to the target value in each load mode, thereby forming the current jump constraints of the current transformer under different load modes. Then, the feedback reorganization rule is built: first, the initial step signal is generated according to the current jump constraints of each load mode (for example, in the light load mode, the current jumps from 20 A to 50 A), and the signal is input into the current transformer. The output current of the transformer is collected in real time through the data acquisition module, and whether the jump amplitude and time of the output current conform to the current jump constraints of the current load mode is compared. If the output exceeds the constraints (for example, the jump amplitude reaches 55 A), the initial step signal parameters are adjusted (to 48 A), and the output is collected again after the signal is input again. The feedback adjustment process is repeated until the output conforms to the constraints. At this time, the response time, overshoot, and steady-state error of the output current are extracted to form the step response indicators under different load modes. Finally, the step response indicators of each load mode (light load, full load, and overload) are sorted in order from low to high according to the load ratio, and a data set is constructed. The trend analysis tool (such as the trend line function of Excel or the curve fitting tool of MATLAB) is used to perform linear fitting or curve drawing on the response time, overshoot, and steady-state error in the data set, respectively. For example, the load ratio is taken as the horizontal axis, and the response time is taken as the vertical axis to draw a curve, the trend of the curve is observed (for example, as the load ratio increases from 20% to 120%, the response time increases from 0.5 ms to 1.8 ms), and then the change rule of the overshoot from 8% to 2% and the steady-state error from 0.3% to 0.8% is combined, and the trend of the curve is taken as the step response trend of the current transformer under different load modes.

[0028] It should be noted that in this application, the current jump constraint refers to the boundary parameters that limit the current transformer when the current changes suddenly under different load modes; the step response indicator is a parameter set that reflects the core characteristics of the step response; and the step response trend refers to the law of the response characteristics of the current transformer changing with the load.

[0029] Preferably, in this embodiment, the step response trend and the loop disturbance limit of the current when the corresponding range is switched are used to generate the directional current injection excitation in the operation test of the current transformer, and reference is made to FIG. 2. Figure 2 FIG. 2 is a flowchart for determining the directional current injection excitation in some embodiments of the present application, and the directional current injection excitation in this embodiment can be achieved by the following steps: In step S21, the step response trend is analyzed to extract dynamic injection information of the current transformer at different ranges; In step S22, the loop disturbance limit when the current switches at the corresponding range is determined; In step S23, the excitation compensation description when the current transformer is tested is determined according to the loop disturbance limit; In step S24, the directional injection excitation when the current transformer is tested is determined according to all the dynamic injection information and the excitation compensation description.

[0030] In specific implementation, first, the step response trend is classified according to the current transformer range (such as 100A, 300A, 500A), and the corresponding response curve of each range is determined. Use data analysis tools (such as Python Pandas library) to disassemble the curves of each range: extract the "current injection rate" corresponding to the response time (such as 100A range response time 0.5ms, corresponding to the current injection rate from 0A to 200A / ms), the "current injection peak control value" corresponding to the overshoot (such as 300A range overshoot 8%, corresponding to the current injection peak controlled within 324A), and then determine the "current injection stable amplitude range" combined with the steady-state error. All the determined parameters are used as the dynamic current injection information of the current transformer under different ranges. Then, the loop data of all range switching scenes (such as 100A→300A, 300A→500A) are selected from the running state data. Use statistical analysis method (such as 99% confidence interval calculation of SPSS) to respectively calculate the current impulse peak value, voltage fluctuation amplitude and disturbance duration of each switching scene: for example, when 100A→300A is switched, the maximum current impulse peak value is 345A, the maximum voltage fluctuation is ±4.8%, and the disturbance lasts for 0.3ms. Combined with the rated tolerance parameters of the transformer (such as the maximum allowed impulse 1.2 times the rated current), the loop disturbance limit of the current during corresponding range switching is obtained. Then, according to the expert experience or the operation manual of the current transformer, the initial current injection excitation parameters corresponding to the range switching are set (such as the initial current injection impulse of 100A→300A is 350A), and the difference between the parameters and the loop disturbance limit (345A) is compared. If it exceeds the limit, use circuit simulation tool (such as PSCAD) to simulate and adjust: for example, extend the current injection rise time from 0.2ms to 0.25ms, and observe that the impulse peak value decreases to 342A, which meets the limit. Record the adjustment method (extend the rise time by 0.05ms), the adjustment parameter value and the disturbance effect after adjustment, and form the excitation compensation description of the current transformer running test. Finally, match the dynamic current injection information of each range with the excitation compensation description corresponding to the range switching one by one: that is, the dynamic current injection information of 300A range requires a current injection rate of 1200A / ms and a stable amplitude of 300A, and the excitation compensation description requires an extension of the rise time by 0.05ms. Use signal generation tool (such as Tektronix function signal generator) to set parameters: the current injection rate is 960A / ms from 0A to 324A (matching the overshoot control), and the stable amplitude is 300A. The rise time is set to 0.31ms according to the compensation requirement. After generating the waveform, use the oscilloscope to verify that it meets the requirements, and determine the directional current injection excitation of the current transformer running test.

[0031] It should be noted that in the present application, the dynamic injection current information refers to a parameter set of the dynamic requirement of the current transformer for the injected current under different ranges; the loop disturbance limit refers to the maximum disturbance boundary of the current and voltage allowed to appear in the loop during the corresponding range switching process of the current transformer; the excitation compensation description is an adjustment scheme for adjusting the initial injection current parameter to make the excitation disturbance meet the loop disturbance limit; the directional injection current excitation refers to the current signal injected by the current transformer in the operation condition test of different ranges.

[0032] In step S3, the implicit failure site of the current transformer under the disturbance condition is determined, the implicit failure site is deviated and spliced to obtain the manifold dielectric loss index of the current transformer in the steady-state modulation calibration in the actual working condition, and then the equivalent frequency response strategy of the current transformer in the operation test is determined by the manifold dielectric loss index.

[0033] In the present embodiment, the determination of the implicit failure site of the current transformer under the disturbance condition can be realized by the following steps: Obtain the multi-modal monitoring data of the current transformer under multiple disturbance conditions; Fuse all the multi-modal monitoring data to obtain the failure hetero-degree attribute of the current transformer under the disturbance condition; Determine the implicit failure site of the current transformer under the disturbance condition according to the failure hetero-degree attribute.

[0034] In a specific implementation, first, three types of core disturbance conditions are determined, namely, a load sudden drop of 50% of the rated load, a voltage sag of 20% of the rated voltage, and injection of a 1 kHz high-frequency harmonic. The transformer is equipped with multiple types of sensors: a 0.05-level current sensor is used to collect primary and secondary side currents, a ±0.1 ℃ precision temperature sensor is used to collect internal and external temperatures, a high-frequency vibration sensor (with a sampling rate of 1 kHz) is used to collect shell vibration, and a dielectric loss tester is used to collect insulation dielectric loss data. In each disturbance condition, corresponding signals are synchronously collected, for example, current and temperature data are continuously collected for 10 seconds during a load sudden drop, dielectric loss data are collected during a high-frequency harmonic, and finally, the data are stored in a database according to the "disturbance condition-signal type" classification. The multi-modal monitoring data of the current transformer under multiple disturbance conditions are read from the database. Then, the D-S evidence theory can be used for heterogeneous fusion. First, the multi-modal monitoring data are preprocessed: the current data are converted into a deviation rate from the rated value (for example, a primary side current of 102 A corresponds to a deviation rate of 2%), the temperature data are converted into a difference from the normal temperature, the vibration data are converted into a peak amplitude, the dielectric loss data are kept as the original test values, and all the data are normalized to the [0, 1] interval. Then, a confidence level is configured for each data (for example, a current deviation of more than 0.5% has a confidence level of 0.8), and the fusion value is calculated through the evidence synthesis rule. Each disturbance condition corresponds to one set of fusion values, which are combined to form the failure heterogeneous attribute of the current transformer under the disturbance condition. Finally, a failure heterogeneous attribute benchmark library of a healthy current transformer is established, which includes the fusion value range of the healthy transformer under each disturbance condition. The current failure heterogeneous attribute is compared with the benchmark library to locate the significantly different fusion dimensions: if the dielectric loss related fusion value difference is more than 30%, the insulation performance is abnormal; if the vibration related fusion value difference is more than 25%, the internal structure is loose. Combined with the transformer packaging structure (which internally includes a winding, a core, and an insulation layer), the dielectric loss abnormality corresponds to an insulation layer implicit degradation site, and the vibration abnormality corresponds to a winding micro-contact poor site, and finally, the implicit failure site of the current transformer under the disturbance condition is formed.

[0035] It should be noted that, in this application, the multi-modal monitoring data refer to the collection of electrical, temperature, vibration, dielectric loss, and electrical signals of the current transformer under different disturbance conditions; the failure heterogeneous attribute refers to the differential characteristic parameter of the current transformer deviating from the healthy operating state; and the implicit failure site refers to a potential fault position of the current transformer under the disturbance condition that cannot be found by conventional testing and will affect the operation accuracy.

[0036] Preferably, in this embodiment, the implicit failure site is subjected to deviation splicing to obtain a manifold dielectric loss index of the current transformer during steady-state modulation calibration in an actual working condition. Referring to Figure 3 The figure is a flowchart for determining the manifold dielectric loss index in some embodiments of the application. The determination of the manifold dielectric loss index in this embodiment can be achieved by the following steps: In step S31, the operating coordination deviation of the current transformer in the actual working condition is determined according to the implicit failure site; In step S32, the elastic flow rule of the current transformer in the actual working condition is determined when the steady-state modulation calibration is performed. In step S33, the dielectric loss deviation tolerance of the current transformer when the current transformer is running in the actual working condition is determined according to the elastic flow rule. In step S34, the manifold dielectric loss index of the current transformer when the steady-state modulation calibration is performed in the actual working condition is determined according to the operating coordination deviation and the dielectric loss deviation tolerance.

[0037] In specific implementation, first, the type of the implicit failure site (such as insulation layer implicit degradation, winding micro contact failure) is determined, and the associated operating parameters are determined for each site: insulation degradation associated dielectric loss and temperature, winding contact failure associated current deviation and vibration. The real-time values of these parameters in the actual working condition are collected by high-precision monitoring equipment, and the parameter benchmark values (such as dielectric loss 0.005 when healthy, 0.008 in actual) in the same working condition under healthy state are retrieved, and the absolute difference between the real-time value and the benchmark value is calculated. All the difference values are sorted according to the "site-parameter" correspondence to form the operating coordination deviation of the current transformer in the actual working condition. Then, the Isomap (Isometric Mapping) algorithm is used to determine the rule. First, collect the high-dimensional data of the steady-state modulation calibration: current, dielectric loss, temperature, vibration, a total of 4 types of parameters under different loads (20%-120% rated load) and different temperatures (-10℃-60℃), forming a high-dimensional data set. The adjacency graph between data points is constructed by the algorithm, and the geodesic distance (reflecting the real distance in high-dimensional space) between any two points is calculated. Then, the high-dimensional data is reduced to 2-dimensional or 3-dimensional space by principal component analysis, retaining the internal correlation of the data, and finally forming the dimension reduction mapping rule. The dimension reduction mapping rule is used as the elastic flow rule of the current transformer when the steady-state modulation calibration is performed in the actual working condition. Then, according to the low-dimensional data processed according to the elastic flow rule, the dielectric loss data points of the current transformer in different steady-state working conditions (such as light load, full load, different temperatures) under healthy state are selected, and the distribution area of the healthy dielectric loss data is fitted in the low-dimensional space. The mean and standard deviation of the dielectric loss data in the area are calculated, and the 3σ criterion is used to determine the upper and lower limits of the dielectric loss fluctuation (such as mean 0.005, standard deviation 0.001, tolerance range 0.002-0.008), and the tolerance range is used as the dielectric loss deviation tolerance of the current transformer when the current transformer is running in the actual working condition. Finally, the deviation values related to dielectric loss in the operating coordination deviation are extracted, and the range and interval length of the dielectric loss deviation tolerance are retrieved. The formula is used to calculate the index: manifold dielectric loss index = (dielectric loss deviation value) / (dielectric loss deviation interval length) × 100. If the index is > 80, it is determined that the dielectric loss is significantly affected by the failure, and if the index is < 30, it is determined that the influence is slight. Finally, the calculation result is output as the manifold dielectric loss index of the current transformer when the steady-state modulation calibration is performed in the actual working condition.

[0038] It should be noted that in the present application, the operation coordination deviation is the difference value of the current transformer various operation parameters deviating from the parameter matching relationship under the healthy state caused by the implicit failure site; the steady-state modulation calibration refers to the process of adjusting the operation parameters of the current transformer under various steady-state conditions to output the accuracy standard; the elastic epidemic rule refers to the dimension reduction and feature retention rule of high-dimensional operation data in the steady-state modulation calibration of the current transformer; the dielectric loss deviation tolerance refers to the maximum reasonable range of the dielectric loss parameter allowed to deviate from the healthy benchmark value when the current transformer is in steady-state operation in the actual working condition; the manifold dielectric loss index refers to the index quantifying the overall health status of the current transformer in the steady-state modulation calibration.

[0039] In the present embodiment, the equivalent frequency response strategy of the current transformer in the operation test determined by the manifold dielectric loss index can be realized by the following steps: determining the switching adaptation gradient of the current transformer in the working condition switching operation according to the manifold dielectric loss index; determining the guide frequency response trajectory of the current transformer in the operation test according to the switching adaptation gradient; determining the equivalent frequency response strategy of the current transformer in the operation test from the guide frequency response trajectory.

[0040] In a specific implementation, first, the dielectric loss index of the flow is divided into three intervals: flow dielectric loss index < 30 (slight impact), 30-80 (moderate impact), and > 80 (significant impact). For each interval, a corresponding switching adaptation gradient is set: when the flow dielectric loss index < 30, the gradient value is set to 0.5 kHz / ms (fast adaptation, fast frequency adjustment); when 30-80, it is set to 0.3 kHz / ms (moderate adaptation, slow adjustment); and when > 80, it is set to 0.1 kHz / ms (weak adaptation, slower adjustment). By matching the index value to the corresponding gradient, the switching adaptation gradient of the current transformer in the working condition switching operation is formed. Then, based on the switching adaptation gradient, the test frequency range is set to 50 Hz-10 kHz. If the switching adaptation gradient is 0.5 kHz / ms, the frequency points are set at 1 kHz intervals (50 Hz, 1 kHz, 2 kHz…10 kHz), and the trajectory is in the order from low to high; when the switching adaptation gradient is 0.3 kHz / ms, the frequency points are set at 0.5 kHz intervals from 50 Hz to 1 kHz, and at 1 kHz intervals above 1 kHz; when the switching adaptation gradient is 0.1 kHz / ms, the frequency points are set at 0.2 kHz intervals throughout the range. Record each frequency point and order to form the guiding frequency response trajectory of the current transformer in the operation test. Finally, key frequency points are selected from the guiding frequency response trajectory: gradient change nodes in the trajectory (such as 1 kHz, 5 kHz) and frequency points with abnormal historical data (such as 3 kHz) are retained. The key nodes are set to a 10-second test dwell time, and the non-key nodes are set to a 3-second test dwell time; the test order is from low to high according to the trajectory, and the current deviation and dielectric loss value at each frequency are recorded simultaneously. Integrate the frequency points, dwell time, and recorded parameters, and use the integrated results as the equivalent frequency response strategy of the current transformer in the operation test. Details are omitted here.

[0041] It should be noted that in this application, the switching adaptation gradient refers to a gradient parameter that quantifies the adaptability of the current transformer to frequency changes during working condition switching; the guiding frequency response trajectory refers to the frequency change path that the current transformer needs to cover in the operation test; and the equivalent frequency response strategy refers to a scheme that dynamically adjusts the frequency and amplitude of the test excitation according to the dielectric loss characteristics to accurately simulate the actual working condition and optimize the test effect.

[0042] In step S4, the differential test of the operating transition characteristics of the current transformer loop in the current operating state is performed according to the directional injection excitation and the equivalent frequency response strategy.

[0043] In a specific implementation, the differential test on the operating transition characteristics of the current transformer in the current operating state according to the directional current injection excitation and the equivalent frequency response strategy can be implemented in the following manner. First, set the signal generator according to the parameters of the directional current injection excitation to generate a current signal containing load mutation and range switching characteristics, and inject the current signal into the primary loop of the current transformer. At the same time, according to the equivalent frequency response strategy, adjust the frequency of the injected signal according to the key frequency points (such as 1 kHz and 5 kHz) in the frequency band of 50 Hz-10 kHz in sequence, and stay at each frequency point for a preset time (such as 10 seconds). In this process, the real-time waveforms of the primary input current and the secondary output current are synchronously collected by using a high-precision oscilloscope, and the waveform changes at the switching moment (such as the load suddenly increasing from 20% to 120%) are recorded. The amplitude difference and the phase difference between the primary and secondary currents at the same time are calculated by using data comparison software, the variation law of these differences with frequency and operating conditions is analyzed, and the operating state of the current transformer under different operating conditions is adjusted according to the variation law, so as to complete the differential test on the operating transition characteristics of the loop. In other embodiments, the current transformer can also be tested in other manners, which is not limited here.

[0044] It should be noted that in this application, the operating transition characteristics refer to the dynamic variation characteristics of the loop current of the current transformer when the operating conditions are switched from one steady state to another steady state; and the differential test refers to a test method for detecting the dynamic performance of the current transformer loop by comparing the differences between the primary input and the secondary output.

[0045] As can be seen, in this application, the comprehensiveness and accuracy of the operating test can be improved in the presence of the defects of the existing current transformer test method, such as lack of correlation between static operating condition detection, dynamic response and hidden faults. The operating state data of the high-precision packaged current transformer during operation can be collected to provide real and full-scene operating condition reference data for the test, avoid the deviation between the traditional laboratory static test and the field dynamic operation, and ensure the accuracy and representativeness of the test basic data. The operating state data is closed-loop reset and the directional current injection excitation is generated, which can simulate the real load mutation and range switching scene, reproduce the dynamic response characteristics under actual operating conditions, solve the problem of disconnection between the traditional excitation signal and the actual operation, and significantly improve the authenticity and safety of the test input. The hidden failure site is determined and the flow pattern dielectric loss index is calculated, which can accurately locate the hidden faults such as insulation deterioration and poor contact that cannot be found by conventional test, quantify the influence degree, avoid the operating risk caused by fault omission, and provide accurate basis for test strategy formulation. The differential test by the directional current injection excitation and the equivalent frequency response strategy can comprehensively verify the transition characteristics of the loop under dynamic operating conditions and key frequencies, realize the correlation evaluation of the process dynamic response and the result static precision, and significantly improve the reliability of the test.

[0046] In summary, the technical solution adopted in this application can accurately stimulate hidden faults in actual operating conditions and verify the status of the current transformer throughout the entire process, thereby improving the accuracy of the current transformer operation test.

[0047] In the second embodiment, the present application provides a high-precision packaged current transformer operation test system, referring to Figure 4 As shown in FIG, this figure is a module structure diagram of an operation test system of a high-precision packaged current transformer according to this embodiment of the present application, and the operation test system includes: The data acquisition module 100 is used to collect the operating status data of the high-precision packaged current transformer during operation; a closed-loop reset module 200 for performing a closed-loop reset on the operating status data to obtain a step response trend of the current transformer under different load modes, and generating a directional current injection excitation during the current transformer operation test based on the step response trend and the loop disturbance limit when the current switches between corresponding ranges; Deviation splicing module 300, for determining the hidden failure location of the current transformer under disturbed working conditions, performing deviation splicing on the hidden failure location, and obtaining the manifold dielectric loss index of the current transformer during steady-state modulation calibration under actual working conditions, and then determining the equivalent frequency response strategy of the current transformer during the operation test based on the manifold dielectric loss index; The differential test module 400 is used to perform a differential test on the operation transition characteristics of the loop of the current transformer in the current operation state according to the directional current injection excitation and the equivalent frequency response strategy.

[0048] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems) and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0049] Those skilled in the art can understand that all or part of the steps of various methods in the above embodiments can be completed by instructing the relevant hardware by means of a program, and the program can be stored in a computer readable storage medium, including Read-Only Memory (ROM), Random Access Memory (RAM), Programmable Read-Only Memory (PROM), Erasable Programmable Read-Only Memory (EPROM), One-time Programmable Read-Only Memory (OTPROM), Electrically-Erasable Programmable Read-Only Memory (EEPROM), Compact Disc Read-Only Memory (CD-ROM) or other optical disk storage, magnetic disk storage, magnetic tape storage, or any other medium that can be used to carry or store data in a computer readable manner.

[0050] It should also be noted that the terms "comprising", "containing", or any other variant thereof are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements, but can also include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the statement "comprising a" does not exclude the existence of additional identical elements in the process, method, article, or apparatus that includes the element.

Claims

1. A method for operating and testing a high-precision packaged current transformer, characterized in that: The operation test method comprises the following steps: Collect the operating status data of high-precision packaged current transformers during operation; Performing a closed-loop reset on the operating status data to obtain a step response trend of the current transformer under different load modes, and generating a directional current injection excitation during the current transformer operation test based on the step response trend and a loop disturbance limit when the current switches between corresponding ranges; Determine the hidden failure locations of the current transformer under disturbed working conditions, perform deviation splicing on the hidden failure locations, and obtain the manifold dielectric loss index of the current transformer during steady-state modulation calibration under actual working conditions. Then, use the manifold dielectric loss index to determine the equivalent frequency response strategy of the current transformer during operation testing. A differential test is performed on the operating transition characteristics of the loop of the current transformer in the current operating state according to the directional current injection excitation and the equivalent frequency response strategy.

2. The operation test method of a high-precision packaged current transformer according to claim 1, characterized in that: Performing a closed-loop reset on the operating status data to obtain the step response trend of the current transformer under different load modes specifically includes: determining a current jump constraint of the current transformer under different load modes according to the operating status data; Feedback and reorganize all current jump constraints to obtain step response signatures under different load modes; The step response trends of the current transformer under different load modes are determined according to all step response identifiers.

3. The operation test method of a high-precision packaged current transformer according to claim 1, characterized in that: The step response trend refers to the law in which the response characteristics of the current transformer change with load.

4. The operation test method of a high-precision packaged current transformer according to claim 1, characterized in that: The directional current injection excitation refers to the current signal injected by the current transformer during the operation condition test of different ranges.

5. The operation test method of a high-precision packaged current transformer according to claim 1, characterized in that: Determining the hidden failure locations of current transformers under disturbance conditions specifically includes: Obtain multi-modal monitoring data of current transformers under various disturbance conditions; All multimodal monitoring data are heterogeneously fused to obtain the failure heterogeneity properties of the current transformer under disturbance conditions; The hidden failure location of the current transformer under the disturbance condition is determined according to the failure heterogeneity attribute.

6. The operation test method of a high-precision packaged current transformer according to claim 1, characterized in that: The hidden failure location refers to a potential fault location of the current transformer under disturbance conditions that is difficult to detect through conventional testing and may affect the operating accuracy.

7. The operation test method of a high-precision packaged current transformer according to claim 1, characterized in that: The strategy for determining the equivalent frequency response of the current transformer during the operation test based on the manifold dielectric loss index specifically includes: Determining a switching adaptation gradient of the current transformer during operating condition switching according to the manifold dielectric loss index; Determining a guided frequency response trajectory of the current transformer during the operation test according to the switching adaptation gradient; The equivalent frequency response strategy of the current transformer during the operation test is determined by the guided frequency response trajectory.

8. The operation test method of a high-precision packaged current transformer according to claim 1, characterized in that: The steady-state modulation calibration is a process in which the output of the current transformer meets the accuracy standard when adjusting the operating parameters under various steady-state conditions.

9. The operation test method of a high-precision packaged current transformer according to claim 1, characterized in that: The operation transition characteristic refers to the dynamic change characteristic of the loop current of the current transformer transitioning from one steady state to another steady state when the working condition is switched.

10. An operation test system for a high-precision packaged current transformer, used to execute an operation test method for a high-precision packaged current transformer according to any one of claims 1 to 9, characterized in that: The operation test system includes: Data acquisition module, used to collect operating status data of high-precision packaged current transformer during operation; a closed-loop reset module, configured to perform a closed-loop reset on the operating status data to obtain a step response trend of the current transformer under different load modes, and generate a directional current injection excitation during the current transformer operation test based on the step response trend and the loop disturbance limit when the current switches between corresponding ranges; A deviation splicing module is used to determine the hidden failure points of the current transformer under disturbed working conditions, perform deviation splicing on the hidden failure points, and obtain the manifold dielectric loss index of the current transformer during steady-state modulation calibration under actual working conditions. The manifold dielectric loss index is then used to determine the equivalent frequency response strategy of the current transformer during operation testing; A differential test module is used to perform a differential test on the operation transition characteristics of the loop of the current transformer in the current operating state according to the directional injection current excitation and the equivalent frequency response strategy.

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