Measurement method and system of transformer value traceability device, electronic equipment and medium

Abstract

The present application relates to the technical field of electrical measurement, and particularly relates to a measurement method and system of a mutual inductor value traceability device, an electronic device and a medium; the method comprises the following steps: firstly, obtaining initial monitoring information of a mutual inductor measurement loop contact point; calculating a drift current interval by using a thermal effect intensity evaluation method; applying a contact pressure adjustment amount to the measurement loop contact point; obtaining compensation monitoring information after the contact pressure adjustment amount is applied; finally, calculating an optimal working current range, a corresponding pressure value interval and a contact resistance stable range according to the compensation monitoring information and a rated measurement current accuracy technical index, so as to serve as an operation basis of the mutual inductor value traceability device in a subsequent measurement process. In this way, the technical problem that the measurement loop stability and the traceability accuracy are difficult to be improved simultaneously in the prior art is solved, and the measurement stability, accuracy and adaptability of the mutual inductor value traceability device are improved.

Description

Technical Field

[0001] This invention relates to the field of electrical measurement technology, and in particular to a measurement method, system, electronic device, and medium for a current transformer value traceability device. Background Technology

[0002] In the field of electrical measurement, the traceability of instrument transformer values ​​is a core element in ensuring the accuracy and reliability of power system measurements. It directly relates to the safe operation of the power grid and the fairness of electricity metering, and is an indispensable technological foundation for the power industry. With the deepening of smart grid construction, the automation level of instrument transformer calibration is continuously improving, and the requirements for the stability and accuracy of measurement circuits are becoming increasingly stringent. Especially during the instrument transformer error verification process, the performance of the measurement circuit directly affects the reliability of the traceability results; therefore, ensuring the stable operation of the circuit under dynamic loads has become a critical requirement.

[0003] In terms of contact resistance monitoring and stability improvement, existing technologies have made some progress, and methods based on online monitoring and model prediction are gradually being applied to the condition assessment of high-voltage equipment. Current mainstream contact resistance monitoring technologies mostly rely on sensor data acquisition and machine learning algorithms to predict resistance values ​​and provide early warnings of anomalies by acquiring contact point parameters in real time. However, the traceability environment for instrument transformer values ​​is complex and dynamic; the contact resistance in the measurement circuit is significantly affected by changes in load current, and existing technologies still have significant limitations in addressing the issues of oxide layer breakdown and thermal effect balance.

[0004] Application publication number CN118777853A discloses an online monitoring method for the contact resistance of high-voltage disconnecting switches based on a support vector machine model. This method predicts resistance values ​​by integrating sensor data and regression algorithms to improve the accuracy of disconnecting switch status assessment. However, this method primarily targets the static parameter monitoring of disconnecting switches. Its feature extraction logic and optimization objectives are better suited for resistance estimation under fixed operating conditions, failing to fully consider the challenges of oxide layer breakdown and thermal effect coupling caused by dynamic changes in load current during transformer calibration. Specifically, existing technologies generally suffer from two prominent problems: First, they fail to effectively handle the interaction between the oxide layer breakdown threshold and thermal effect drift under varying load currents, especially the contradiction between the high resistance state caused by the lack of oxide layer breakdown in the low-current region and the resistance drift caused by temperature rise in the high-current region, significantly reducing the reliability of monitoring results. Second, their ability to model the dynamic characteristics of contact resistance is insufficient, making it difficult to accurately capture the changes in the contribution of film resistance and shrinkage resistance during current changes, resulting in limited accuracy in stability assessment. These problems, when combined, make it difficult for existing technologies to balance measurement accuracy and circuit stability in practical applications of instrument transformer value traceability, and fail to meet the long-term reliable control requirements for contact resistance in high-precision calibration scenarios. Therefore, existing instrument transformer value traceability technologies based on contact resistance monitoring face technical challenges such as an imbalance between oxide layer breakdown and thermal effect control, insufficient dynamic characteristic modeling, and consequently, difficulty in synergistically improving measurement circuit stability and traceability accuracy. Summary of the Invention

[0005] In view of the above-mentioned deficiencies or disadvantages, the present invention provides a measurement method, system, electronic equipment and medium for a current transformer value traceability device, so as to solve the technical problem that it is difficult to simultaneously improve the stability of the measurement circuit and the traceability accuracy in the existing current transformer value traceability technology.

[0006] In a first aspect, the present invention provides a measurement method for a current transformer value traceability device, the method being based on a multi-parameter monitoring module and a dynamic pressure adjustment module deployed in the current transformer measurement circuit, comprising:

[0007] The initial monitoring information of the contact points of the current transformer measurement circuit is obtained through the multi-parameter monitoring module.

[0008] Based on the breakdown state characteristics constructed from the resistance fluctuation characteristics and temperature response curves in the initial monitoring information, the drift current range is calculated using the thermal effect intensity assessment method. The breakdown state characteristics are used to characterize the physical breakdown state of the oxide layer at the contact point under different load current intensities, and the drift current range is used to characterize the current operating range in which the temperature rise at the contact point causes the contact resistance value to drift.

[0009] The dynamic pressure adjustment module applies a contact pressure adjustment to the contact point of the transformer measurement circuit. The adjustment amount is calculated based on the resistance drift amplitude and drift rate obtained from real-time monitoring of the contact resistance within the drift current range.

[0010] The multi-parameter monitoring module obtains compensation monitoring information of the contact points of the current transformer measurement circuit after the applied contact pressure adjustment.

[0011] Based on the compensation monitoring information and the rated measurement current accuracy technical indicators of the current transformer measurement circuit configured with the current transformer value traceability device, the optimal operating current range, corresponding pressure value range, and contact resistance stability range of the current transformer measurement circuit are calculated.

[0012] Secondly, the present invention provides a measurement system for a current transformer value traceability device. This measurement system is based on a multi-parameter monitoring module and a dynamic pressure adjustment module deployed in the current transformer measurement circuit, and includes:

[0013] The initial monitoring information acquisition module is used to acquire the initial monitoring information of the contact points of the transformer measurement circuit through the multi-parameter monitoring module.

[0014] The drift current range calculation module is used to calculate the drift current range based on the breakdown state characteristics constructed from the resistance fluctuation characteristics and temperature response curves in the initial monitoring information, using the thermal effect intensity assessment method. The breakdown state characteristics are used to characterize the physical breakdown state of the oxide layer at the contact point under different load current intensities, and the drift current range is used to characterize the current operating range in which the temperature rise at the contact point causes the contact resistance value to drift.

[0015] The contact pressure dynamic adjustment module is used to apply a contact pressure adjustment amount to the contact point of the current transformer measurement circuit. The adjustment amount is calculated based on the resistance drift amplitude and drift rate obtained by real-time monitoring of the contact resistance within the drift current range.

[0016] The compensation monitoring information acquisition module is used to acquire the compensation monitoring information of the current transformer measurement circuit contact points after the applied contact pressure adjustment is obtained through the multi-parameter monitoring module.

[0017] The device measurement result generation module is used to calculate the optimal operating current range, corresponding pressure value range, and contact resistance stability range of the transformer measurement circuit based on the compensation monitoring information and the rated measurement current accuracy technical indicators configured in the transformer value traceability device.

[0018] Thirdly, the present invention provides an electronic device, comprising:

[0019] At least one processor; and a memory communicatively connected to the at least one processor;

[0020] The memory stores instructions that can be executed by the at least one processor, which, when executed by the at least one processor, enables the at least one processor to perform the measurement method of any current transformer value traceability device of the present invention.

[0021] Fourthly, the present invention provides a non-transient computer-readable storage medium storing computer instructions, wherein the computer instructions are used to cause a computer to execute the measurement method of any current transformer value traceability device of the present invention.

[0022] The present invention provides a measurement method for a current transformer value traceability device. This method is achieved through the coordinated operation of a multi-parameter monitoring module and a dynamic pressure adjustment module deployed in the current transformer measurement circuit. The multi-parameter monitoring module is used to synchronously collect information on the resistance, temperature, and oxide layer thickness of the contact points, while the dynamic pressure adjustment module is used to achieve online adjustment of the contact pressure. The method includes: first, obtaining initial monitoring information of the contact points of the current transformer measurement circuit through the multi-parameter monitoring module; then, calculating the drift current range based on the breakdown state characteristics constructed from the resistance fluctuation characteristics and temperature response curves in the initial monitoring information using a thermal effect intensity evaluation method; next, applying a contact pressure adjustment amount to the contact points of the current transformer measurement circuit through the dynamic pressure adjustment module; subsequently, obtaining compensation monitoring information after the application of the contact pressure adjustment amount through the multi-parameter monitoring module; finally, calculating the optimal operating current range, the corresponding pressure value range, and the stable contact resistance range based on the compensation monitoring information and the rated measurement current accuracy technical indicators configured in the current transformer value traceability device.

[0023] In this technical solution, the present invention addresses the problem of the difficulty in synergistically improving contact resistance stability and measurement accuracy, as mentioned in the background art. By constructing breakdown state characteristics and calculating drift current ranges, it achieves quantitative identification of the high-resistance state of the oxide layer without breakdown and the drift caused by overcurrent thermal effects, overcoming the deficiency of traditional methods in accurately characterizing the dynamic characteristics of contact resistance under varying load current. Regarding the lack of theoretical basis for contact pressure adjustment, the invention calculates the contact pressure adjustment amount based on real-time monitored resistance drift amplitude and drift rate, establishing a dynamic mapping relationship between contact state and pressure parameters. Addressing the insufficient optimization of measurement circuit operating parameters, the optimal operating range for ensuring traceability accuracy is determined through a comprehensive evaluation of compensation monitoring information and accuracy technical indicators. Therefore, the technical solution of this invention solves the technical problem of the difficulty in synergistically improving measurement circuit stability and traceability accuracy in existing instrument transformer value traceability technologies, achieving deep synergy between contact state monitoring, dynamic pressure adjustment, and measurement accuracy assurance, thus improving the measurement stability, accuracy, and adaptability of the instrument transformer value traceability device. Attached Figure Description

[0024] Figure 1This is a flowchart of a measurement method for a current transformer value traceability device according to an embodiment of the present invention;

[0025] Figure 2 This is a flowchart illustrating a method for improving the measurement accuracy of a current transformer value traceability device according to another embodiment of the present invention.

[0026] Figure 3 This is a schematic diagram of the measurement system of a current transformer value traceability device according to an embodiment of the present invention;

[0027] Figure 4 This is a block diagram of an electronic device used to implement embodiments of the present invention. Detailed Implementation

[0028] The following description, in conjunction with the accompanying drawings, illustrates exemplary embodiments of the present invention, including various details to aid understanding. These details should be considered merely exemplary. Therefore, those skilled in the art will recognize that various changes and modifications can be made to the embodiments described herein without departing from the scope of the invention. Similarly, for clarity and brevity, descriptions of well-known functions and structures are omitted in the following description.

[0029] During the development of this invention, the inventors, through extensive experiments and data analysis, revealed the intrinsic relationship between contact resistance stability and oxide layer breakdown characteristics, as well as the coupling relationship with thermal effects: the drift characteristics of contact resistance not only depend on the oxide layer thickness, but also form a dynamic coupling relationship with the degree of oxide layer breakdown under load current and the resulting Joule heating effect. Based on this relationship, the inventors innovatively proposed this technical solution, utilizing multi-parameter collaborative monitoring technology, quantitatively characterizing breakdown state features, and combining a dynamic pressure compensation mechanism to achieve autonomous optimization and control of the measurement circuit's operating state, embodying the core concept of "state perception - feature extraction - dynamic adjustment - closed-loop optimization".

[0030] Specifically, through comparative experiments, the invention team discovered three major technical defects in traditional fixed-pressure contact resistance control methods: first, they cannot identify the oxide layer breakdown critical point; second, they lack a thermal effect drift early warning mechanism; and third, they lack pressure adaptive adjustment capabilities. These defects cause the contact resistance fluctuation of the measurement circuit to exceed 15% of the initial value within the load current range of 1 ampere to 10 amperes, severely affecting measurement accuracy. However, the multi-parameter dynamic optimization method proposed in this invention can improve contact resistance stability to a fluctuation range of less than 3%; through real-time identification of breakdown state characteristics and drift current ranges, automatic compensation for contact pressure accuracy of 0.1 Newtons can be achieved; and through the autonomous determination of the optimal operating range, the current transformer value traceability device can maintain an accuracy of 0.2 class under 85% of operating conditions.

[0031] Therefore, this invention provides a measurement method for a current transformer value traceability device according to the first aspect, which can be applied to an intelligent current transformer value traceability system (hereinafter referred to as the "system"). This system can run on an industrial control computer via embedded software or a cloud computing platform to complete the tasks of controlling the contact resistance stability and improving the measurement accuracy of the current transformer measurement circuit. Specifically, this system can be deployed in various hardware environments, including but not limited to: industrial computers, embedded microcontrollers, and server clusters. This flexible deployment architecture allows the system to meet the real-time requirements of high-precision measurement for computing resources while adapting to the complex operating conditions of different substation environments.

[0032] like Figure 1 As shown, this method is based on a multi-parameter monitoring module and a dynamic pressure adjustment module deployed in the transformer measurement circuit. The transformer measurement circuit refers to the electrical path used for error verification during the transformer value traceability process, including primary and secondary measurement circuits. The physical state of the contact points (such as contact resistance) directly affects the circuit impedance and load current, thus determining the measurement accuracy. This circuit typically includes automatic wiring or crimping links and is a key part of the traceability device for current transmission and signal acquisition. The multi-parameter monitoring module refers to an integrated monitoring device deployed at the contact points of the transformer measurement circuit, used to simultaneously acquire multi-dimensional parameters such as contact resistance, temperature data, and oxide layer thickness. It achieves real-time data acquisition through units such as contact resistance monitors and temperature acquisition devices, providing basic input for assessing oxide layer breakdown state and thermal effects. The dynamic pressure adjustment module refers to an actuator that can dynamically apply mechanical pressure based on monitoring data. It determines the pressure adjustment amount by calculating the contact resistance drift amplitude and rate, and adjusts the contact point pressure using electric actuators to suppress resistance instability caused by the oxide layer and ensure the stability of the measurement circuit. This method may include:

[0033] Step S110: Obtain the initial monitoring information of the contact point of the current transformer measurement circuit through the multi-parameter monitoring module.

[0034] The initial monitoring information refers to a set of multi-dimensional physical quantities, including contact point resistance, temperature data, and oxide layer thickness, obtained through synchronous acquisition of multiple parameters. This information is the basic data characterizing the current conductivity and thermal stability of the contact point.

[0035] Specifically, the system can acquire resistance values ​​using the four-wire method through the contact resistance monitoring unit of the multi-parameter monitoring module, and acquire temperature data using an attached temperature sensor through the temperature acquisition unit. When an abnormality in the temperature coefficient of resistance is detected, the oxide layer analysis unit applies an AC excitation signal to measure the impedance spectrum characteristics and calculate the oxide layer thickness. For example, in a measurement loop containing six key contact points, the system acquires six sets of complete monitoring data within the same sampling period through six independent monitoring channels: a resistance value of 2.15 milliohms, a temperature of 45.3 degrees Celsius, and an oxide layer thickness of 0.12 micrometers for contact point A; and a resistance value of 3.07 milliohms, a temperature of 47.8 degrees Celsius, and an oxide layer thickness of 0.25 micrometers for contact point B.

[0036] Step S120: Based on the breakdown state characteristics constructed from the resistance fluctuation characteristics and temperature response curves in the initial monitoring information, the drift current range is calculated using the thermal effect intensity assessment method.

[0037] Among them, the breakdown state characteristics are used to characterize the physical breakdown state of the oxide layer at the contact point under different load current intensities; the drift current range is used to characterize the current operating range in which the contact resistance value drifts due to the temperature rise at the contact point; the resistance fluctuation characteristics refer to the fluctuation amplitude and frequency of the contact resistance value as a function of the load current; the temperature response curve refers to the temperature rise rate curve of the contact point as a function of the load current; and the thermal effect intensity assessment method refers to the quantitative analysis method of the relationship between temperature rise and current established based on Joule's law of thermodynamics and the thermal resistance model.

[0038] Specifically, the system can construct a three-dimensional resistance-temperature-current response surface and extract the current range where the resistance change rate exceeds 5% per ampere as a characteristic range. Within this range, the critical point of oxide layer breakdown can be analyzed. For example, within a test range of 1 ampere to 10 amperes, the system identifies a drift current range of 3.5 amperes to 7.2 amperes, within which the temperature rise drift rate of the contact resistance exceeds 0.5% per degree Celsius.

[0039] Step S130: Apply a contact pressure adjustment amount to the contact point of the current transformer measurement circuit through the dynamic pressure adjustment module.

[0040] The adjustment amount is calculated based on the resistance drift amplitude and drift rate obtained from real-time monitoring of the contact resistance within the drift current range. In other words, the (contact pressure) adjustment amount refers to the additional pressure value that needs to be applied to suppress contact resistance drift. The value of the additional pressure value is equal to the algebraic difference between the target pressure value and the current measured pressure. The resistance drift amplitude refers to the maximum deviation of the contact resistance from the initial stable value, and the drift rate refers to the change in resistance value per unit time.

[0041] Specifically, the system can monitor resistance changes within the drift range in real time. When the detected drift amplitude exceeds 5% or the drift rate exceeds 0.01 ohms per second, it triggers the pressure adjustment mechanism. For example, if the system detects that the resistance of a contact point drifts from 2.15 milliohms to 2.48 milliohms (drift amplitude 15.3%) and the drift rate is 0.015 ohms per second, it calculates that an additional 12.5 Newtons of contact pressure adjustment is required.

[0042] Step S140: Obtain compensation monitoring information of the current transformer measurement circuit contact point after the applied contact pressure adjustment through the multi-parameter monitoring module.

[0043] Among them, the compensation monitoring information refers to the set of contact point resistance, temperature and oxide layer thickness data re-collected after pressure adjustment, which is used to verify the pressure adjustment effect and evaluate system stability.

[0044] Specifically, the system can obtain a compensated multi-parameter dataset by re-executing the monitoring process of step S110 after the pressure adjustment has stabilized for 30 seconds. For example, after applying an adjustment pressure of 12.5 Newtons, the system re-monitors and finds that the resistance value of contact point A has recovered to 2.18 milliohms, the temperature has dropped to 42.1 degrees Celsius, and the oxide layer thickness has not changed significantly, indicating that the pressure adjustment is effective.

[0045] Step S150: Calculate the optimal operating current range, corresponding pressure value range, and contact resistance stability range of the transformer measurement circuit based on the compensation monitoring information and the rated measurement current accuracy technical indicators configured in the transformer value traceability device.

[0046] Among them, the optimal operating current range refers to the maximum permissible operating current range that meets accuracy requirements; the corresponding pressure value range refers to the pressure adjustment range required to maintain stable contact resistance within this current range; and the contact resistance stability range refers to the permissible fluctuation range of contact resistance under optimal operating conditions. These optimal operating current ranges, corresponding pressure value ranges, and contact resistance stability ranges are used as the operational basis for the current transformer value traceability device in subsequent measurement processes.

[0047] Specifically, the system can determine the current-pressure combination parameters that meet the accuracy requirements by comparing the compensated resistance stability data with the device's accuracy class requirements (such as 0.2 class). For example, the system determines that the optimal operating current range for this measurement circuit is 4.2 amps to 6.8 amps, corresponding to a pressure value range of 18.5 newtons to 25.3 newtons. Under this parameter combination, the contact resistance is stable within the range of 2.15 ± 0.05 milliohms, meeting the 0.2 class accuracy requirements.

[0048] like Figure 2This diagram illustrates a method for improving the measurement accuracy of a current transformer traceability device. This method can improve the accuracy of current transformers of specific models (e.g., 0.2 accuracy). The method includes: First, the system performs an initialization step, collecting data on the resistance, temperature fluctuation, and oxide layer thickness of the contact points in the current transformer's measurement circuit to obtain initial monitoring information. Specifically, the system connects the primary measurement circuit of the current transformer under test to an automated testing platform, ensuring reliable connection between the various sensors of the multi-parameter monitoring module (including a contact resistance monitor, a patch temperature sensor, and an oxide layer analysis probe) and six preset key contact points (marked as P1 to P6). Next, the system controls the load current source to output a stepped current sequence starting at 0.5 amperes and increasing in 0.5-ampere increments to 10 amperes. During the 5-second period when each current step remains stable, the system synchronously performs data acquisition: the contact resistance monitoring unit measures the resistance value of each contact point using the four-wire method (e.g., at 2 amperes, the resistance at point P1 is 1.85 milliohms); the temperature acquisition unit reads the temperature at each point (e.g., the temperature at point P1 is 38.4 degrees Celsius); and the oxide layer analysis unit automatically applies an AC excitation signal with a frequency scanning from 100 Hz to 10 MHz when a sudden change in the slope of the resistance-temperature curve is detected at a certain point. The oxide layer thickness at that point is calculated based on the inflection frequency of the impedance phase spectrum (e.g., the calculated oxide layer thickness at point P1 is 0.08 micrometers). This process completes step S101, acquiring a complete initial monitoring information set.

[0049] Subsequently, the system enters the state assessment phase. Based on the resistance fluctuation characteristics and temperature response curves in the initial monitoring information of the contact points, it assesses the breakdown state of the oxide layer under different load current intensities, obtaining the breakdown depth, breakdown area ratio, and corresponding critical breakdown current value of the oxide layer after the current increases. Specifically, the system uses a specific software algorithm to process the initial monitoring information, generating resistance-current and temperature-current curves for each contact point. The system identifies that for contact point P1, its resistance value drops sharply (the rate of change exceeds 8%) when the load current increases from 3 amps to 4 amps, and at the same time, the temperature rise rate curve at this point shows a significant inflection point. Based on this, it is determined that the oxide layer breaks down at a current of approximately 3.5 amps, and this current value is recorded as the critical breakdown current value. The system further invokes a preset algorithm, combining the infrared thermal image (taken by an integrated thermal imager) and the potential distribution map (measured by a micro-area probe) at the moment of breakdown, to calculate that the oxide layer breakdown depth is approximately 0.05 micrometers, and the breakdown area accounts for approximately 60% of the theoretical contact area. These parameters together constitute the breakdown state characteristics of the contact point, completing the core analysis of step S102.

[0050] Next, based on the breakdown state characteristics, the system performs a thermal effect assessment. According to the breakdown current critical value, oxide layer breakdown depth, and breakdown area ratio, it evaluates the intensity of the thermal effect generated after the current increases and breaks down the oxide layer, identifies the correspondence between the contact point temperature rise and the current intensity, and confirms the current range in which the temperature rise causes the contact resistance value to drift. The algorithm is based on the formula: "Power density per unit area = The instantaneous power density at the breakdown point is calculated using the formula: × contact resistance / breakdown area. Then, by analyzing the current greater than... The system uses temperature data collected (e.g., in the range of 4 to 7 amps) to fit an approximate linear relationship between the temperature rise rate and the current, and calculates the equivalent thermal resistance coefficient of the contact point. Finally, the model predicts that when the current is greater than 6.8 amps, the steady-state temperature rise will cause a drift rate of more than 0.5% per degree Celsius in the contact resistance. Therefore, the range of 4.0 amps to 6.8 amps is marked as the drift current range, completing step S103.

[0051] During the control execution phase, the system performs real-time monitoring within the drift current range (e.g., setting the test current to 5.5 amps). Based on the current range where resistance drift is caused by temperature rise and the real-time monitored resistance value, it evaluates the drift amplitude and drift rate of the contact resistance, identifies the resistance threshold and temperature threshold where the drift exceeds the stable range, and determines the amount of contact pressure adjustment required to suppress the drift. For example, when the contact resistance at point P1 is detected to drift from 1.88 milliohms to 1.96 milliohms within 30 seconds (drift amplitude of approximately 4.3%), and the instantaneous drift rate is calculated to be 0.006 ohms per second, the system determines that it is close to the preset stability threshold (e.g., 5% amplitude or 0.01 ohms per second rate). Based on the Hertzian contact theory model, the control logic calculates that the current contact pressure of 20 Newtons needs to be increased to 24 Newtons to effectively suppress the drift trend. This calculation result (4 Newtons of pressure adjustment) is sent to the control unit of the dynamic pressure adjustment module, completing the decision in step S104.

[0052] Next, the system applies an adjustment to the contact point of the measurement circuit, collecting data on the resistance, temperature change, and oxide layer thickness after pressure adjustment. This obtains compensated contact point monitoring information, identifies the current range where the resistance drift is less than the initial monitoring value and the drift rate is lower than the set rate of change, evaluates the fluctuation amplitude and frequency of the contact resistance within this current range, and determines the upper and lower limits of the stable operating current. Specifically, the system can precisely adjust the contact pressure at point P1 to 24 Newtons through the pressure execution unit (such as an electric servo lever) of the dynamic pressure adjustment module. After the pressure stabilizes, the system again collects data through the multi-parameter monitoring module, obtaining compensated monitoring information: the resistance at point P1 drops and stabilizes at 1.89 milliohms, and the temperature decreases slightly from 51.2 degrees Celsius to 49.8 degrees Celsius. The system repeats the test within a drift current range of 4.0 amps and 6.8 amps, verifying that under the adjusted pressure, the resistance drift amplitude is controlled within 1.5%, and the drift rate is less than 0.002 ohms per second, meeting the preset stability requirements. This step corresponds to the verification of the compensated state and the confirmation of the stable current boundary in step S105.

[0053] Finally, the system performs parameter optimization. Based on the upper and lower limits of the stable operating current, it compares the error allowable range in the accuracy technical specifications of the rated measuring current of the transformer traceability device. This identifies the accuracy of the measuring circuit under different current intensities, obtains the current operating range that meets traceability requirements, adjusts the contact pressure and load current intensity, and determines the optimal operating current range, corresponding pressure value range, and stable contact resistance range of the measuring circuit, thus realizing the analysis of transformer value traceability. Specifically, the algorithm compares the current range that meets stability verification (e.g., 4.5~6.5 amps) with the error limit required for the transformer traceability device's own 0.2-level accuracy (e.g., relative error less than 5 amps). The system compares the current with the pressure within this current range (e.g., from 22 N to 26 N) to find the widest parameter window that simultaneously satisfies accuracy and stability. Ultimately, the system outputs that the optimal operating current range for this measurement loop for this current transformer is 5.0~6.0 Amps, and the recommended pressure range (in Newtons) is [insert range here]. Under this combination, the expected stable range of contact resistance is: Milliohms. This set of parameters will serve as the core operational basis for subsequent high-precision measurement traceability of the current transformer, thus completing the final optimization and output of step S106. This example demonstrates through specific data and operational procedures... Figure 2 How does the method shown... Figure 1 The logical flow is applied to actual testing scenarios. Through systematic and data-driven iterative adjustments, the optimal working parameters that can simultaneously ensure measurement stability and traceability accuracy are finally obtained.

[0054] Therefore, according to the above implementation method, the system obtains the initial monitoring information of the contact point of the transformer measurement circuit through the multi-parameter monitoring module; then, based on the breakdown state characteristics constructed from the resistance fluctuation characteristics and temperature response curve in the initial monitoring information, the drift current range is calculated using the thermal effect intensity evaluation method; then, the contact pressure adjustment amount is applied to the contact point of the transformer measurement circuit through the dynamic pressure adjustment module; subsequently, the compensation monitoring information after the application of the contact pressure adjustment amount is obtained through the multi-parameter monitoring module; finally, the optimal operating current range, the corresponding pressure value range, and the contact resistance stability range are calculated based on the compensation monitoring information and the rated measurement current accuracy technical indicators configured in the transformer value traceability device.

[0055] Specifically, in this embodiment, addressing the problem of the difficulty in synergistically improving contact resistance stability and measurement accuracy as mentioned in the background technology, the present invention achieves quantitative identification of the high-resistance state of the oxide layer without breakdown and the drift due to overcurrent thermal effects by constructing breakdown state characteristics and calculating drift current range. This solves the defect of traditional methods in accurately characterizing the dynamic characteristics of contact resistance under load current changes. Regarding the lack of theoretical basis for contact pressure adjustment, the contact pressure adjustment amount is calculated based on the real-time monitored resistance drift amplitude and drift rate, establishing a dynamic mapping relationship between contact state and pressure parameters. Addressing the problem of insufficient optimization of measurement circuit operating parameters, the optimal operating range for ensuring traceability accuracy is determined through a comprehensive evaluation of compensation monitoring information and accuracy technical indicators. Therefore, the technical solution of this invention solves the technical problem of the difficulty in synergistically improving measurement circuit stability and traceability accuracy in existing current transformer value traceability technologies, achieving deep synergy between contact state monitoring, dynamic pressure adjustment, and measurement accuracy assurance, thus improving the measurement stability, accuracy, and adaptability of the current transformer value traceability device.

[0056] In some embodiments, the multi-parameter monitoring module is configured with a contact resistance monitoring unit, a temperature acquisition unit, and an oxide layer analysis unit; the initial monitoring information of the contact points of the transformer measurement circuit is obtained through the multi-parameter monitoring module, including:

[0057] The resistance value of the contact point of the transformer measurement circuit is obtained from the electrical signal measurement of the transformer measurement circuit by the contact resistance monitoring unit.

[0058] Electrical signal measurement refers to the measurement process using the four-wire method (Kelvin connection method). This involves applying a known, constant test current to the contact point and measuring the precise voltage drop across the contact point, then calculating the resistance value using Ohm's law. This method eliminates the influence of lead resistance on the measurement results.

[0059] Specifically, the contact resistance monitoring unit includes a constant current source and a high-precision differential voltmeter. The constant current source injects a stable DC current (e.g., 10 mA) into the contact point being measured, and the differential voltmeter simultaneously measures the voltage difference generated across the contact point as this current flows through it. For example, when the test current is 10 mA, the voltage difference between contact points A and B is measured to be 21.5 mV. According to the formula: Resistance = Voltage Difference / Test Current, the resistance of the contact point is calculated to be: 21.5 mV / 10 mA = 2.15 mΩ.

[0060] The temperature data of the current transformer measurement circuit contact point is obtained from the sensing signal output by the temperature sensor attached to the contact point of the current transformer measurement circuit by the temperature acquisition unit.

[0061] Among them, "attachment" refers to the physical installation method of the temperature sensor being tightly coupled to the contact point surface through thermally conductive silicone grease; the sensing signal refers to the analog or digital electrical signal generated by the resistance value of the temperature sensor (such as platinum resistance thermometer PT100) as the temperature changes.

[0062] Specifically, the temperature acquisition unit includes a signal conditioning circuit and an analog-to-digital converter (ADC). The signal conditioning circuit converts the resistance change of the temperature sensor into a standard voltage signal, and the ADC converts this analog voltage signal into a digital quantity that can be read by a microprocessor. For example, a PT100 sensor attached to a contact point has a resistance of 115.54 ohms at 45.3 degrees Celsius. The temperature acquisition unit measures this resistance value and performs a lookup calculation according to the PT100's calibration table, ultimately outputting the digital temperature value of 45.3 degrees Celsius.

[0063] In response to the slope of the resistance value changing with temperature exceeding a preset threshold, an AC excitation signal is applied to the contact point of the transformer measurement circuit through the oxide layer analysis unit, the relationship curve between impedance phase angle and frequency is measured, and the oxide layer thickness is calculated from the inflection point frequency of the relationship curve.

[0064] Among them, the slope of the resistance value changing with temperature (i.e., the temperature coefficient of resistance) refers to the relative change in resistance caused by a unit temperature change; the preset threshold is a judgment value set according to the theoretical temperature coefficient of resistance of metal materials and the insulation characteristics of oxide layer, which is used to trigger oxide layer analysis; the inflection point frequency refers to the characteristic frequency point in the impedance phase angle-frequency relationship curve where the phase angle changes sharply, and this point corresponds to the relaxation frequency of oxide layer medium.

[0065] Specifically, the oxide layer analysis unit includes a sweep frequency signal generator and a phase detection circuit. When a certain contact point is detected... When the voltage ((2.20 mΩ - 2.15 mΩ) / (50°C - 30°C) = 0.0025 mΩ / °C) exceeds the threshold (e.g., 0.002 mΩ / °C), the unit starts. The signal generator produces a sinusoidal excitation signal that scans from 100 Hz to 10 MHz and applies it to the contact point. The phase detection circuit synchronously measures the phase difference (i.e., impedance phase angle) between the voltage and current signals.

[0066] For example, the analysis unit measured a significant inflection point in the impedance phase angle at a frequency of 2.5 MHz, abruptly shifting from near 0 degrees to near 0 degrees. Degree. According to the physical model of the medium, the oxide layer thickness. With inflection point frequency Satisfy approximation relationship ,in A constant related to the contact area and material. Let be the dielectric constant of the oxide layer. Substitute the constant and the measured ... Hertzian calculations yielded an oxide layer thickness of approximately 0.12 micrometers. Among these, This is a constant related to the contact area and the material.

[0067] Among them, resistance value, temperature data and oxide layer thickness constitute the initial monitoring information.

[0068] Specifically, "structure" refers to aligning and packaging resistance, temperature, and oxide layer thickness data collected from different monitoring units at the same time or under the same load current condition, according to contact point numbering, to form a structured data set used to characterize the complete physical characteristics of that contact point in its current state. For example, in the system... Under stable conditions with a load current of 5 amps, the following initial monitoring information data packet was collected and generated for contact point #1: resistance value 2.15 milliohms, temperature 45.3 degrees Celsius, oxide layer thickness 0.12 micrometers.

[0069] Therefore, according to the above implementation method, the system can synchronously and accurately acquire multidimensional physical quantities that reflect the contact point's conductivity, thermal state, and surface dielectric properties, providing accurate and reliable initial data input for subsequent evaluation of oxide layer breakdown state, analysis of thermal effect drift range, and calculation of pressure adjustment.

[0070] In some embodiments, the step of constructing the breakdown state feature includes:

[0071] Based on the resistance fluctuation characteristics and temperature response curves in the initial monitoring information, a correlation model between resistance, temperature, and current parameters is constructed.

[0072] Among them, resistance fluctuation characteristics refer to the random fluctuation amplitude and trend of contact resistance value when the load current changes; temperature response curve refers to the continuous trajectory of contact point temperature changing with load current (or time); correlation model refers to an expression established by mathematical methods (such as multiple nonlinear regression) to describe the quantitative relationship between resistance (R), temperature (T) and load current (I).

[0073] Specifically, the system can use a microprocessor to call a statistical algorithm library, using the resistance and temperature values ​​collected at different load current points as sample data, and fit a result such as... An approximate function of , where As a residual, this function reveals the macroscopic laws governing the change of resistance with current and temperature. For example, based on data collected at five current points of 1, 2, 3, 4, and 5 amperes, the system fits an empirical model: (Unit: milliohms) The model shows that the resistance increases with the square of the current, providing an initial indication of the potential impact of the Joule heating effect.

[0074] Extract the current range where the resistance change rate exceeds a preset threshold from the correlation model, and identify the feature points where the oxide layer begins to break down within the current range.

[0075] The rate of change of resistance refers to the relative change in resistance caused by a unit change in current, i.e. The preset threshold is an empirically set threshold value used to determine whether the resistance change is drastic enough to characterize the oxide layer as "softly broken down"; the feature point refers to the data point on the resistance-current curve where the slope first changes abruptly.

[0076] Specifically, the system can improve the correlation model function. Find information about current. partial derivatives Then, the derivative curve is scanned to locate the current point where its value first exceeds a preset threshold (e.g., 0.15 milliohms / ampere). For example, the derivative curve is calculated at the current... Ampere, The value jumps from 0.08 milliohms / ampere to 0.22 milliohms / ampere, exceeding the threshold of 0.15 milliohms / ampere. The system identifies this current point of 3.4 amperes as the characteristic current point at which oxide layer breakdown begins.

[0077] The contact resistance stabilization time is monitored by using an incremental load current method, and the breakdown current critical value is determined based on the turning point when the stabilization time suddenly changes from the second level to the millisecond level.

[0078] Among them, the incremental load current method refers to gradually increasing the current applied to the measurement circuit in fixed steps (e.g., 0.1 amperes); the contact resistance settling time refers to the time it takes for the contact resistance value to fluctuate within a preset stable bandwidth under a certain constant current (e.g., ...). The required duration within ) ; the inflection point refers to the critical state where the settling time changes by an order of magnitude with increasing current (e.g., from >1 second to <10 milliseconds).

[0079] Specifically, the system can control a programmable power supply to slowly increase the current, starting from the characteristic point current, in smaller steps (e.g., 0.05 amps). During each current step hold period, the contact resistance value is sampled at high frequency, and its standard deviation is calculated in real time using an algorithm. When the standard deviation is less than a threshold for N consecutive sampling periods, the system is considered to have entered a steady state, and the time elapsed from the start of the current step to entering the steady state is recorded. For example, the system measured a settling time of 2.1 seconds at 3.4 amps, 1.8 seconds at 3.45 amps, and a sudden decrease to 8 milliseconds at 3.50 amps. The system then determines 3.50 amps as the breakdown current critical value. At this point, the oxide layer is completely broken down, and a conductive channel is rapidly established.

[0080] Based on the critical value of breakdown current, the breakdown depth and breakdown area ratio of the oxide layer are calculated by measuring the potential distribution and analyzing thermal imaging.

[0081] Among them, potential distribution measurement refers to scanning the surface of the contact point with a micro probe array to obtain a two-dimensional distribution map of the local potential difference before and after breakdown; thermal imaging analysis refers to taking an image of the surface temperature field distribution when current flows through the contact point using an infrared thermal imager; breakdown depth refers to the physical thickness of the oxide layer that is ablated or penetrated by the current channel; breakdown area ratio refers to the ratio of the area where breakdown occurs to the total theoretical electrical contact area.

[0082] Specifically, the system can reach the breakdown current threshold. Under stable operation, the four-probe micro-area potential measurement module is simultaneously activated to scan the contact surface and triggers an infrared thermal imager to take pictures. By analyzing the boundaries of areas with significant gradients in the potential distribution map, the outline of the breakdown region is determined; by analyzing the range of the high-temperature area in the thermal image, the breakdown region is further confirmed. Breakdown depth. Through formula To make an estimate, among which The resistivity of the oxide layer, For breakdown current density, The characteristic time of the breakdown process, For specific heat capacity, Temperature rise. Percentage of breakdown area. This is obtained by calculating the ratio of the profile area of ​​the breakdown region to the apparent area of ​​the contact point. For example, potential and thermal imaging analysis together determine that the breakdown region is approximately circular, with a calculated diameter of about 50 micrometers. The breakdown depth is then estimated by substituting the parameters. Approximately 0.05 micrometers. The area of ​​this circular region, compared to the total area of ​​contact points with a diameter of 200 micrometers, represents the percentage of the breakdown area. Approximately: .

[0083] The breakdown state characteristics are constructed based on the breakdown current critical value, breakdown depth, and breakdown area ratio.

[0084] Here, "construction" refers to combining the three calculated or measured scalar parameters into a feature vector or data structure with specific physical meaning, used to uniquely characterize the breakdown behavior of the oxide layer at the contact point under specific load conditions. Specifically, the system can create a data structure (struct) or array to... The three parameters are stored in a preset order, along with metadata such as timestamps and contact point IDs. For example, the breakdown state characteristic constructed by the system for contact point #1 can be represented as: ampere, micrometer, This feature set quantitatively describes the breakdown of the oxide layer at 3.50 amperes, with shallow breakdown depths but concentrated in a small area.

[0085] Therefore, according to the above implementation method, the system can automatically and quantitatively extract the key physical parameters of oxide layer breakdown from the original resistance and temperature monitoring data through multi-step processing such as modeling, differentiation, dynamic testing and image analysis. This transforms the abstract "contact state" into specific and comparable digital features, providing accurate input basis for subsequent evaluation of thermal effect drift and calculation of pressure compensation.

[0086] In some embodiments, based on the breakdown state characteristics constructed from the resistance fluctuation characteristics and temperature response curves in the initial monitoring information, the drift current range is calculated using a thermal effect intensity assessment method, including:

[0087] Based on the breakdown current critical value, breakdown depth and breakdown area ratio, the power density per unit area of ​​the current transformer measurement circuit contact point is calculated.

[0088] The system calculates power density per unit area using the following formula: .in, The breakdown current threshold, This is the contact resistance value at this current. The percentage of the area that is penetrated. This represents the nominal geometric area of ​​the contact point. For example, given the breakdown characteristics: ampere, milliohm, , The square meter (corresponding to a circular contact point with a diameter of 200 micrometers) is substituted into the formula for calculation:

[0089] Watts per square meter.

[0090] The temperature field distribution characteristics are generated by scanning using infrared thermal imaging technology, based on the intensity of the thermal effect determined by the power density per unit area. The nominal area of ​​the contact point can be obtained through geometric measurement.

[0091] The temperature field distribution characteristics are generated by scanning with infrared thermal imaging technology based on the intensity of the thermal effect determined by the power density per unit area.

[0092] Here, the thermal effect intensity is a function of the power density per unit area, used to qualitatively describe the severity of heating; the temperature field distribution characteristics refer to a two-dimensional image or data matrix obtained by an infrared thermal imager, reflecting the temperature levels at various locations on the contact surface. Specifically, the system operates when the current is slightly higher than the breakdown current critical value (e.g., The system operates stably under conditions of (ampere) and controls the infrared thermal imager to scan the contact area. The thermal imager converts the infrared radiation from the object's surface into temperature values ​​and generates a temperature matrix in pixels, which represents the temperature field distribution characteristics. For example, the infrared thermal imager scans and obtains a... The temperature matrix of the pixels shows that the highest temperature in the central region (corresponding to the breakdown point) is 86.5 degrees Celsius, while the temperature in the edge region is about 45.0 degrees Celsius. This temperature gradient image visually shows the areas where heat is concentrated.

[0093] The thermal resistance coefficient is calculated by analyzing the relationship between the temperature rise rate and the current intensity based on the surface temperature of the contact point collected by an infrared thermal imager under different load currents.

[0094] Among them, the temperature rise rate refers to the rate of change of the surface temperature of the contact point over time before it reaches a steady state (unit: degrees Celsius / second); the thermal resistance coefficient is a physical parameter characterizing the heat dissipation capacity of the contact point, and its value is the ratio between the steady-state temperature rise and the heat power that generates the temperature rise (unit: degrees Celsius / watt).

[0095] Specifically, the system in to Multiple test points were selected within the current range (e.g., 3.5, 4.0, 4.5, 5.0, 5.5, 6.0, 6.5, 7.0 amperes). At each current point, the temperature-time curve was recorded from the instant the current was applied until the temperature stabilized (e.g., the temperature change was less than 0.1 degrees Celsius within 5 consecutive seconds), and the average temperature rise rate was calculated. Assuming the heat dissipation process conforms to Newton's law of cooling, the steady-state temperature rise... With thermal power Proportional, the proportionality coefficient is the thermal resistance ,satisfy By linearly fitting different currents ( The slope of the data points is the thermal resistance coefficient. For example, the steady-state temperature rises at 4.0, 5.0, and 6.0 amperes were measured to be 15, 30, and 50 degrees Celsius, respectively, corresponding to thermal powers of 35.2, 55.0, and 79.2 milliwatts. Linear fitting yielded: Therefore, thermal resistance coefficient It is approximately 625.3 degrees Celsius per watt.

[0096] A mathematical model of current intensity and steady-state temperature rise is constructed based on the thermal resistance coefficient. The mathematical model is used to perform predictive analysis of steady-state temperature and corresponding contact resistance change rate under various current values, thereby generating the drift current range.

[0097] Among them, the mathematical model of current intensity and steady-state temperature rise refers to a function based on the thermal resistance coefficient, used to predict the steady-state temperature that the contact point will reach under any given load current; the contact resistance change rate refers to the relative change in resistance caused by temperature change, usually described by the temperature coefficient of resistance; the predictive analysis operation refers to the process of substituting a series of candidate current values ​​into the mathematical model, calculating the predicted steady-state temperature rise and the resistance drift estimated therefrom, and comparing it with the preset stability tolerance.

[0098] Specifically, the mathematical model is as follows: ,in For ambient temperature, For current The contact resistance is given below (which can be obtained from the correlation model). The formula for estimating the rate of change of resistance is: ,in The temperature coefficient of resistance of the contact material. The system uses the reference temperature as a reference. Within the current range of interest (e.g., 3.0 amps to 8.0 amps), it generates a current sequence in 0.1 amp steps, and sequentially calculates the predicted steady-state temperature rise and rate of change of resistance. Current points where the rate of change of resistance exceeds a preset tolerance (e.g., 0.5%) are selected; the continuous interval formed by these current points is the drift current interval. For example, setting... Celsius / degrees Celsius (typical value for copper). Celsius Celsius / watt. Calculations show that when the current... At amperes, the predicted rate of change in resistance will exceed 0.5%. Therefore, the system generates drift current in the range of... The ampere indicates that when operating within this range, the resistance drift caused by thermal effects will be significant.

[0099] Therefore, according to the above implementation method, the system can quantitatively calculate the local heat source intensity from the characteristic parameters characterizing oxide layer breakdown, and establish an accurate thermal-electric coupling prediction model by combining the measured temperature field and thermal resistance characteristics. Based on this model, it can proactively identify the current operating range that will cause significant thermal drift in contact resistance, thereby providing a clear and quantitative target range for subsequent pressure adjustment decisions. This realizes an intelligent analysis chain from "phenomenon observation" to "mechanism modeling" and then to "risk prediction".

[0100] In some embodiments, the step of calculating the adjustment amount includes:

[0101] The contact resistance value is continuously monitored at a preset sampling frequency within the drift current range, and the instantaneous drift rate data sequence is calculated.

[0102] Among them, the preset sampling frequency refers to the number of times the data acquisition system measures the contact resistance per second; the instantaneous drift rate refers to the rate of change of the contact resistance value relative to the previous sampling time at a certain sampling moment.

[0103] Specifically, the system control data acquisition card (DAQ) performs analog-to-digital conversion (ADC) on the voltage signal output by the contact resistance monitoring unit at a fixed frequency (e.g., 1000 Hz), and converts the continuous resistance sample values... Stored in a circular buffer. Instantaneous drift rate. Through formula Calculation, where The sampling interval is 1 / 1000 = 0.001 seconds. For example, at the 5.0 ampere operating point within the drift current range, the system samples continuously at a frequency of 1000 Hz. Resistance measured in seconds milliohm, in Resistance measured in seconds If the value is milliohm, then the instantaneous drift rate at that moment is calculated. Ohms per second.

[0104] The maximum value and arithmetic mean of the instantaneous drift rate data sequence within the monitoring period are statistically analyzed, and the maximum deviation of the contact resistance value from the initial stable value is recorded as the drift amplitude.

[0105] The monitoring period refers to the continuous sampling time window set for this assessment; the drift amplitude refers to the maximum absolute difference between the contact resistance value and its initial stable value within this monitoring period, usually expressed as... It means that, among them This is the stable resistance value recorded at the set current at the beginning of the monitoring cycle.

[0106] Specifically, after a complete monitoring cycle (e.g., 10 seconds) ends, the system stores all instantaneous drift rates in the buffer. Perform statistical analysis and calculate its maximum value. and arithmetic mean Simultaneously, all resistance samples within that period are iterated over. Find out The absolute value of the largest difference is the drift amplitude. For example, within a 10-second monitoring period, the system measures the instantaneous drift rate. Ohms per second, Ohms per second. The initial stable value of the resistance during this period. The maximum recorded resistance was 2.200 milliohms, while the maximum recorded resistance was 2.260 milliohms and the minimum was 2.195 milliohms. Therefore, the maximum deviation (drift amplitude) is... haoou.

[0107] In response to a preset percentage increase in drift amplitude beyond the initial resistance value or an increase in the arithmetic mean of instantaneous drift rates beyond a preset rate of change, the resistance value at the trigger determination time is recorded as the resistance threshold and the corresponding temperature value is recorded as the temperature threshold.

[0108] Among them, the preset percentage refers to the limit relative value of the contact resistance that is allowed to change relative to its initial value; the preset rate of change refers to the limit value of the average rate of change of the resistance that is allowed; the trigger determination time refers to the precise time point at which the system logic determines that any of the above conditions are met; the resistance threshold refers to the critical resistance value recorded at the determination time that indicates that the contact state is close to instability; and the temperature threshold refers to the contact point temperature corresponding to the critical resistance value that is recorded synchronously at the determination time.

[0109] Specifically, the system compares two judgment conditions in real time:

[0110] 1. ;

[0111] 2. .

[0112] Once any condition is met, the system immediately records the real-time resistance sample value at that moment (the determination time). As resistance threshold And record the temperature value at this moment, which is synchronously acquired from the temperature acquisition unit. As a temperature threshold For example, setting , Ohms per second. Measured within a certain monitoring period. milliohm, The relative change is as follows: (milliohm) Condition 1 is triggered. The system records the trigger time. milliohms Corresponding temperature The temperature is .

[0113] Based on the resistance threshold and temperature threshold, Hertzian contact theory is applied to calculate the minimum contact pressure required to reduce the contact resistance to the threshold level at the current temperature, and the difference between the target pressure value and the current measured pressure value is used as the adjustment amount.

[0114] Hertzian contact theory refers to a classical mechanical model describing the relationship between the contact area and contact pressure, the elastic modulus of the materials, and the radius of curvature of two elastic bodies under pressure. The target pressure value refers to the value calculated according to the model that is expected to stabilize the contact resistance at a threshold value. The following are theoretical values ​​of contact pressure; the current measured pressure value refers to the actual pressure applied to the contact point in real time, which is fed back by the pressure sensing unit; the adjustment amount is the algebraic difference between the target pressure value and the current measured pressure value, which is the direct command value that drives the dynamic pressure adjustment module.

[0115] Specifically, the system's control algorithm is based on Hertzian contact formulas. For spherical or cylindrical contact points, the contact radius... With contact pressure The relationship is: ,in A constant related to the geometry and radius of curvature. This is the equivalent elastic modulus. Contact resistance... With contact radius Approximately inversely proportional, satisfying By considering the effect of temperature on the resistivity of materials, it can be deduced that at a specific temperature... Below, in order to achieve the target resistance Minimum contact pressure required Adjustment amount That is ,in This refers to the current measured pressure value. For example, if the current measured pressure is known... Newton, current temperature Celsius, resistance threshold Milliohms. Calculations based on material parameters and models determine the minimum contact pressure required to reduce the theoretical contact resistance to below 2.200 milliohms (i.e., better than the threshold) at this temperature. Newton. Therefore, the contact pressure adjustment amount is calculated. Newton.

[0116] Therefore, according to the above implementation method, the system can accurately identify the critical state of contact resistance instability based on real-time, high-precision monitoring and statistical analysis of the dynamic characteristics of resistance within the drift current range, and quantitatively calculate the minimum pressure compensation value required to suppress the drift using a classical physical model. This transforms the fuzzy, empirical "voltage adjustment" operation into a precise, model-based closed-loop control command, providing core algorithm support for maintaining high stability of the measurement loop under dynamic load.

[0117] In some embodiments, the dynamic pressure adjustment module is configured with a pressure actuation unit, a pressure sensing unit, and a control unit; applying a contact pressure adjustment amount to the contact point of the current transformer measurement circuit through the dynamic pressure adjustment module includes:

[0118] The control unit receives the adjustment amount and generates pressure control commands.

[0119] Among them, pressure control commands refer to the adjustments received by the control unit's computing core (such as a microprocessor). The calculations show that the digital or analog signal used to drive the pressure actuator typically contains a target pressure value (equivalent to the required minimum contact pressure). The control parameters include the direction of motion (increase or decrease) and control parameters (such as proportional-integral-derivative, i.e., PID parameters). PID (Proportional-Integral-Derivative) refers to the proportional-integral-derivative (controller). It is a closed-loop control algorithm widely used in industrial control systems.

[0120] Specifically, the control unit reads the adjustment amount sent from the upstream computing module (which executes the logic of step S104). and compared with the currently stored measured pressure value Add them together to get the target pressure value. Subsequently, the control unit, based on a preset servo control algorithm, will... Converted into a signal format suitable for driving the actuator. For example, the control unit receives... Newton's adjustment, currently Newton calculated The control unit then generates a digital command containing the target value of 23.5 Newtons and the control mode (such as position mode), and sends it to the actuator of the pressure actuator via a fieldbus (such as a CAN bus). Here, CAN (Controller Area Network) refers to the controller area network bus.

[0121] The pressure actuator responds to the pressure control command and generates mechanical displacement to apply a contact pressure adjustment to the contact point of the transformer measurement circuit.

[0122] Mechanical displacement refers to the linear or rotary motion generated by the output components (such as push rods and pressure heads) of the pressure actuator under the action of the drive source. This motion is converted into positive pressure on the contact point through the transmission mechanism.

[0123] Specifically, after receiving a control command, the driver of the pressure actuator (such as a servo electric cylinder or voice coil motor) drives the motor to rotate. This rotational motion is then converted into linear motion of the push rod via a ball screw or direct drive mechanism, thereby pushing the pressure head towards the contact point and applying pressure. For example, a servo electric cylinder, upon receiving a control command... Upon receiving Newton's command, its actuator controls the motor to rotate, driving the push rod to extend by 0.5 mm. Due to the elasticity of the contact point and its supporting structure, this displacement generates an additional 3.5 Newtons of pressure, increasing the total pressure from 20.0 Newtons to 23.5 Newtons.

[0124] The pressure sensing unit detects the actual pressure value at the contact point in real time and transmits it to the control unit.

[0125] The actual pressure value refers to the magnitude of the force applied to the contact point, which is obtained by directly measuring or indirectly converting the pressure through a pressure sensor. It is a key feedback quantity for closed-loop control.

[0126] Specifically, pressure sensing units (such as strain gauge force sensors) are installed between the pressure head and the contact point or along the force transmission path of the actuator. The sensor converts the sensed force signal into a proportional electrical signal (such as voltage or current). After signal conditioning and ADC, the signal is transmitted in digital form to the control unit in real time via a communication interface (such as RS-485 or analog input). For example, an analog voltage-type force sensor with a range of 50 Newtons and an output of 0-10 volts will output approximately 4.7 volts when sensing a pressure of 23.5 Newtons. The analog input module (AI module) of the control unit acquires this voltage and converts it according to the sensor calibration coefficient (10 volts / 50 Newtons = 0.2 volts / Newton) to obtain the actual pressure value. Newton, and then update this value to the storage unit.

[0127] The control unit compares the actual pressure value with the target pressure value and dynamically adjusts the pressure control command based on the difference until the actual pressure value stabilizes within the target pressure range.

[0128] The target pressure range refers to the pressure range around the target pressure value. A permissible fluctuation range, for example ( (for tolerance); dynamic adjustment refers to the control unit adjusting according to the actual pressure. With target pressure value Real-time error The control algorithm (such as PID control) is used to recalculate and output the corrected pressure control command, forming a closed-loop feedback regulation process.

[0129] Specifically, the control unit reads periodically (e.g., every 1 millisecond). And calculate the error The PID controller calculates a correction based on the proportional, integral, and derivative terms of the error. This correction is used to adjust the commands sent to the pressure actuator driver (such as adjusting the target position or target torque), thereby driving the actuator. Towards Approaching. When The system is considered stable when it remains within the target range (e.g., 23.5 ± 0.1 Newtons) for a preset duration (e.g., 100 milliseconds). For example, after the initial pressure is applied, The feedback is 23.0 Newtons, with an error of Newton. The PID controller calculates that the position of the electric cylinder push rod needs to be finely adjusted by 0.05 mm. After adjustment, It becomes 23.4 Newtons. After several such adjustment cycles, Eventually stabilized Within the range of Newton's law, the control unit immediately stops making large adjustments and enters a maintenance state.

[0130] Therefore, according to the above implementation method, the system can achieve precise, closed-loop servo control of contact pressure. This is achieved through the close coordination of four stages: instruction generation, high-precision execution, real-time sensor feedback, and dynamic algorithm adjustment.

[0131] In some embodiments, the optimal operating current range, corresponding pressure value range, and contact resistance stability range of the transformer measurement circuit are calculated based on compensation monitoring information and the rated measurement current accuracy technical indicators configured in the transformer value traceability device, including:

[0132] Based on the resistance drift amplitude, drift rate, and oxide layer state parameters in the compensation monitoring information, candidate current points that meet the preset stability threshold are selected within the drift current range.

[0133] Among them, the preset stability threshold refers to a set of quantitative standards that are pre-set to determine whether the contact resistance has reached a stable working state at a certain current point. These usually include the upper limit of drift amplitude and the upper limit of drift rate. The candidate current point refers to the discrete current value in the drift current range whose corresponding dynamic parameters of the contact resistance simultaneously meet all the preset stability threshold requirements.

[0134] Specifically, the system reads the test current points recorded in the compensation monitoring information within the drift current range. Resistance drift amplitude and drift rate Then, for each current point and Each with a preset amplitude threshold (e.g., 0.5%) and rate threshold (e.g., 0.01 ohms per second) for comparison. Only when and When both conditions are met, the current point Only then will it be marked as a candidate current point. For example, the drift current range is... The system tested 10 current points within this range in 0.2 ampere increments. Comparison revealed that the current points of 6.4, 6.6, 6.8, 7.0, and 7.2 amperes showed the following results: milliohms (corresponding to 0.5%) (milliohm) and The current values ​​are measured in ohms per second, satisfying all preset thresholds. Therefore, these five current values ​​are selected as candidate current points and stored in an array. ampere.

[0135] The measurement error corresponding to the candidate current point is compared and verified with the error limit specified in the technical specification of the accuracy of the rated measurement current to determine the effective current range that meets the accuracy requirements.

[0136] Among them, measurement error refers to the deviation between the measured value of the current transformer traceability device and the standard value at a certain current point, usually expressed as relative error; error limit refers to the maximum absolute value of the measurement error allowed by the device within the rated current range at its accuracy class (e.g., 0.2 class); effective current range refers to the largest continuous sub-range formed by those continuous current points among all candidate current points whose measurement errors do not exceed the error limit. Specifically, the system targets arrays... Each candidate current point in The standard verification procedure of the traceability device is invoked to obtain the relative measurement error at that point. (Expressed as a percentage). Subsequently, The corresponding error limit specified in the technical specifications of the device (For class 0.2, typically 5% to 120% of rated current) ) for comparison. Only when Only when the candidate point meets the accuracy requirements is the accuracy requirement considered met. Finally, the system finds the largest numerically continuous subset from all the points that meet the requirements, and uses its minimum and maximum values ​​as the lower limit of the effective current range. and upper limit For example, for Error measurements were performed at 5 points, and the results were as follows: , , , , .set up A comparison reveals that... The error has exceeded the limit in amperes. Therefore, the points that meet the accuracy requirements are 6.4 and 6.6 amperes. The largest continuous subinterval formed by them is... Ampere, therefore the effective current range is determined: ,in ampere, ampere.

[0137] Within the effective current range, the contact pressure is adjusted in steps to monitor the contact resistance fluctuation at each pressure point, and the pressure value at which the resistance value remains within the preset fluctuation range is recorded.

[0138] Among them, the stepping method refers to following a pre-set pressure change step size. (like (Newton), the contact pressure is changed sequentially within the pressure adjustment range; the preset fluctuation range refers to the maximum bandwidth allowed for instantaneous fluctuation of the contact resistance to determine whether it is "stable" under a certain pressure, and is usually expressed as the stable value. (like The recorded pressure values ​​refer to all contact pressure test values ​​that, at a certain current point within the effective current range, can maintain the real-time fluctuation of the contact resistance within a preset fluctuation range.

[0139] Specifically, the system selects a representative current point within the effective current range. (For example, the midpoint can be taken) After the current stabilizes, the system controls the dynamic pressure adjustment module to adjust the pressure from the initial pressure. Start with pressure change step size Gradually increase or decrease the contact pressure at each pressure set point. After stabilization (e.g., 5 seconds), the system samples the contact resistance at a high frequency (e.g., 1000 Hz). The duration is a certain period of time (e.g., 10 seconds). Calculate the time within this period. fluctuation range And check if it meets the requirements. (in This represents the average value of the contact resistance. (The set volatility is a preset value, such as 0.005). If this is satisfied, record the current pressure setpoint. This is a valid pressure value. For example, at the point representing the current. Under ampere pressure, initial pressure Newton. The system is based on... Using Newtons as the increment, the pressure was increased from 22.0 Newtons to 25.0 Newtons. Tests revealed that the resistance fluctuation ranges over 10 seconds for pressures of 23.0 Newtons, 23.5 Newtons, and 24.0 Newtons were as follows: milliohm, milliohm, milliohms, their relative fluctuations are all (Right now The pressure values ​​meet the preset fluctuation range requirements. Therefore, the system records these three pressure values: Newton.

[0140] The minimum current value in the effective current range is used as the lower limit of the optimal operating current range, and the maximum current value is used as the upper limit. The minimum value among the recorded pressure values ​​is used as the lower limit of the corresponding pressure value range, and the maximum value is used as the upper limit. The minimum and maximum values ​​of the contact resistance measured within the pressure value range are used as the stable range of the contact resistance.

[0141] Among them, the optimal operating current range refers to the continuous range of load current that is ultimately recommended to users and can simultaneously meet the requirements of stability and accuracy; the corresponding pressure value range refers to the acceptable pressure adjustment range recommended to maintain stable contact resistance within the optimal operating current range; and the contact resistance stability range refers to the upper and lower limits of the contact resistance value that is expected to be maintained under the above combination of current and pressure ranges.

[0142] Specifically, the system directly retrieves As the lower limit of the optimal operating current range ,Pick As the upper limit of the optimal operating current range Thus, the range is obtained. For a pressure value range, the system selects from an array of pressure values. Find the minimum value in As the lower limit of the interval maximum value As the upper limit of the interval , obtain range Finally, the system is in the pressure range. Inside, at the point representing the current. The final round of fine-tuning tests was then conducted, and the minimum contact resistance value observed in all tests was recorded. and maximum value The minimum and maximum values ​​are taken as the stable range of contact resistance. For example, based on the data above, the system determines the optimal operating current range. ampere, Ampere. The corresponding pressure range is... Newton, Newton. In Under ampere pressure, the minimum resistance was finally measured within the range of 23.0 Newtons to 24.0 Newtons. milliohms, maximum value Milliohms. Therefore, the final output result is: recommended to operate at a current of 6.4 to 6.6 amps and adjust the contact pressure between 23.0 and 24.0 newtons, under which the contact resistance is expected to stabilize in the range of 2.195 to 2.208 milliohms.

[0143] Therefore, according to the above implementation method, the system can automatically determine a practically operable parameter window that achieves optimal balance in three dimensions—electrical performance (current), mechanical parameters (pressure), and core state quantity (resistance)—through quantitative analysis of the compensated monitoring data and layer-by-layer screening. This method transforms a complex multi-objective optimization problem into a series of explicit judgment and search steps based on measured data, thereby providing users with specific, reliable, and optimized operational guidance for tracing the values ​​of current transformers.

[0144] Figure 3 This is a structural block diagram of the measurement system of a current transformer value traceability device according to an embodiment of the present invention.

[0145] like Figure 3 As shown, the measurement system of this instrument transformer value traceability device, based on a multi-parameter monitoring module and a dynamic pressure adjustment module deployed in the instrument transformer measurement loop, includes:

[0146] The initial monitoring information acquisition module 210 is used to acquire the initial monitoring information of the contact point of the transformer measurement circuit through the multi-parameter monitoring module.

[0147] The drift current range calculation module 220 is used to calculate the drift current range based on the breakdown state characteristics constructed from the resistance fluctuation characteristics and temperature response curve in the initial monitoring information and using the thermal effect intensity evaluation method. The breakdown state characteristics are used to characterize the physical breakdown state of the oxide layer at the contact point under different load current intensities, and the drift current range is used to characterize the current operating range in which the temperature rise at the contact point causes the contact resistance value to drift.

[0148] The contact pressure dynamic adjustment module 230 is used to apply a contact pressure adjustment amount to the contact point of the transformer measurement circuit through the dynamic pressure adjustment module. The adjustment amount is calculated based on the resistance drift amplitude and drift rate obtained by real-time monitoring of the contact resistance within the drift current range.

[0149] The compensation monitoring information acquisition module 240 is used to acquire the compensation monitoring information of the current transformer measurement circuit contact point after the applied contact pressure adjustment is applied through the multi-parameter monitoring module.

[0150] The device measurement result generation module 250 is used to calculate the optimal operating current range, corresponding pressure value range, and contact resistance stability range of the transformer measurement circuit based on the compensation monitoring information and the rated measurement current accuracy technical indicators configured in the transformer value traceability device.

[0151] The specific functions and examples of each module and submodule of the device in this embodiment can be found in the relevant descriptions of the corresponding steps in the above method embodiments, and will not be repeated here.

[0152] According to embodiments of the present invention, the above-described method of the present invention can be applied to an electronic device and a readable storage medium.

[0153] Figure 4 A schematic block diagram of an example electronic device 600 that can be used to implement embodiments of the present invention is shown. The electronic device is intended to represent various forms of digital computers, such as laptop computers, desktop computers, workstations, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. The electronic device may also represent various forms of mobile devices, such as personal digital assistants, cellular phones, smartphones, wearable devices, and other similar computing devices. The components shown herein, their connections and relationships, and their functions are merely illustrative and are not intended to limit the implementation of the invention described and / or claimed herein.

[0154] like Figure 4 As shown, the electronic device 600 includes a computing unit 601, which can perform various appropriate actions and processes based on a computer program stored in a read-only memory (ROM) 602 or a computer program loaded from a storage unit 608 into a random access memory (RAM) 603. The RAM 603 may also store various programs and data required for the operation of the electronic device 600. The computing unit 601, ROM 602, and RAM 603 are interconnected via a bus 604. An input / output (I / O) interface 605 is also connected to the bus 604.

[0155] Multiple components in electronic device 600 are connected to I / O interface 605, including: input unit 606, such as keyboard, mouse, etc.; output unit 607, such as various types of displays, speakers, etc.; storage unit 608, such as disk, optical disk, etc.; and communication unit 609, such as network card, modem, wireless transceiver, etc. Communication unit 609 allows electronic device 600 to exchange information / data with other devices through computer networks such as the Internet and / or various telecommunications networks.

[0156] The computing unit 601 can be various general-purpose and / or special-purpose processing components with processing and computing capabilities. Some examples of the computing unit 601 include, but are not limited to, a central processing unit (CPU), a graphics processing unit (GPU), various special-purpose artificial intelligence (AI) computing chips, various computing units running machine learning model algorithms, a digital signal processor (DSP), and any suitable processor, controller, microcontroller, etc. The computing unit 601 performs the various methods and processes described above, such as a measurement method for a current transformer value traceability device. For example, in some embodiments, a measurement method for a current transformer value traceability device can be implemented as a computer software program, which is tangibly contained in a machine-readable medium, such as storage unit 608. In some embodiments, part or all of the computer program can be loaded and / or installed on the electronic device 600 via ROM 602 and / or communication unit 609. When the computer program is loaded into RAM 603 and executed by the computing unit 601, one or more steps of the measurement method for a current transformer value traceability device described above can be performed. Alternatively, in other embodiments, the computing unit 601 may be configured by any other suitable means (e.g., by means of firmware) to perform a measurement method of a current transformer value tracing device.

[0157] Various embodiments of the systems and techniques described above herein can be implemented in digital electronic circuit systems, integrated circuit systems, field-programmable gate arrays (FPGAs), application-specific integrated circuits (ASICs), application-specific standard products (ASSPs), systems-on-a-chip (SoCs), payload-programmable logic devices (CPLDs), computer hardware, firmware, software, and / or combinations thereof. These various embodiments may include implementations in one or more computer programs that can be executed and / or interpreted on a programmable system including at least one programmable processor, which may be a dedicated or general-purpose programmable processor, capable of receiving data and instructions from a storage system, at least one input device, and at least one output device, and transmitting data and instructions to the storage system, the at least one input device, and the at least one output device.

[0158] The program code used to implement the methods of the present invention can be written in any combination of one or more programming languages. This program code can be provided to a processor or controller of a general-purpose computer, special-purpose computer, or other programmable data processing device, such that when executed by the processor or controller, the program code causes the functions / operations specified in the flowcharts and / or block diagrams to be implemented. The program code can be executed entirely on the machine, partially on the machine, as a standalone software package partially on the machine and partially on a remote machine, or entirely on a remote machine or server.

[0159] In the context of this invention, a machine-readable medium can be a tangible medium that may contain or store a program for use by or in conjunction with an instruction execution system, apparatus, or device. A machine-readable medium can be a machine-readable signal medium or a machine-readable storage medium. Machine-readable media can include, but are not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatus, or devices, or any suitable combination of the foregoing. More specific examples of machine-readable storage media include electrical connections based on one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fibers, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination of the foregoing.

[0160] To provide interaction with a user, the systems and techniques described herein can be implemented on a computer having: a display device for displaying information to the user (e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor); and a keyboard and pointing device (e.g., a mouse or trackball) through which the user provides input to the computer. Other types of devices can also be used to provide interaction with the user; for example, feedback provided to the user can be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user can be received in any form (including sound input, voice input, or tactile input).

[0161] The systems and technologies described herein can be implemented in computing systems that include backend components (e.g., as a data server), or computing systems that include middleware components (e.g., an application server), or computing systems that include frontend components (e.g., a user computer with a graphical user interface or web browser through which a user can interact with implementations of the systems and technologies described herein), or any combination of such backend, middleware, or frontend components. The components of the system can be interconnected via digital data communication of any form or medium (e.g., a communication network). Examples of communication networks include local area networks (LANs), wide area networks (WANs), and the Internet.

[0162] Computer systems can include clients and servers. Clients and servers are generally located far apart and typically interact via communication networks. Client-server relationships are created by computer programs running on the respective computers and having a client-server relationship with each other. Servers can be cloud servers, servers in distributed systems, or servers incorporating blockchain technology.

[0163] It should be understood that the various forms of processes shown above can be used to reorder, add, or delete steps. For example, the steps described in this invention can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution disclosed in this invention can be achieved, and this is not limited herein.

[0164] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the principles of this invention should be included within the scope of protection of this invention.

Claims

1. A measurement method for a current transformer value traceability device, characterized in that, The method is based on a multi-parameter monitoring module and a dynamic pressure adjustment module deployed in the current transformer measurement circuit, including: The initial monitoring information of the contact point of the current transformer measurement circuit is obtained through the multi-parameter monitoring module. Based on the breakdown state characteristics constructed from the resistance fluctuation characteristics and temperature response curves in the initial monitoring information, the drift current range is calculated using the thermal effect intensity assessment method. The breakdown state characteristics are used to characterize the physical breakdown state of the oxide layer at the contact point under different load current intensities, and the drift current range is used to characterize the current operating range in which the temperature rise at the contact point causes the contact resistance value to drift. The dynamic pressure adjustment module applies a contact pressure adjustment amount to the contact point of the transformer measurement circuit. The adjustment amount is calculated based on the resistance drift amplitude and drift rate obtained from real-time monitoring of the contact resistance within the drift current range. The multi-parameter monitoring module obtains compensation monitoring information of the contact points of the current transformer measurement circuit after the applied contact pressure adjustment has been applied. Based on the compensation monitoring information and the rated measurement current accuracy technical indicators configured in the current transformer value traceability device, the optimal operating current range, corresponding pressure value range, and contact resistance stability range of the current transformer measurement circuit are calculated.

2. The method according to claim 1, characterized in that, The multi-parameter monitoring module is equipped with a contact resistance monitoring unit, a temperature acquisition unit, and an oxide layer analysis unit; the initial monitoring information of the contact points of the transformer measurement circuit obtained through the multi-parameter monitoring module includes: The resistance value of the contact point of the current transformer measurement circuit is obtained from the electrical signal measurement of the current transformer measurement circuit by the contact resistance monitoring unit. The temperature data of the contact point of the current transformer measurement circuit is obtained from the sensing signal output by the temperature sensor attached to the contact point of the current transformer measurement circuit by the temperature acquisition unit. In response to the slope of the resistance value changing with temperature exceeding a preset threshold, an AC excitation signal is applied to the contact point of the current transformer measurement circuit through the oxide layer analysis unit, the relationship curve between impedance phase angle and frequency is measured, and the oxide layer thickness is calculated from the inflection frequency of the relationship curve. The resistance value, the temperature data, and the oxide layer thickness constitute the initial monitoring information.

3. The method according to claim 2, characterized in that, The steps for constructing the breakdown state characteristics include: Based on the resistance fluctuation characteristics and temperature response curve in the initial monitoring information, a correlation model between resistance, temperature, and current parameters is constructed. Extract current ranges where the resistance change rate exceeds a preset threshold from the correlation model, and identify feature points where the oxide layer begins to break down within the current range. The contact resistance stabilization time is monitored by using an incremental load current method, and the breakdown current critical value is determined based on the turning point when the stabilization time suddenly changes from the second level to the millisecond level. Based on the aforementioned critical breakdown current value, the breakdown depth and breakdown area ratio of the oxide layer are calculated through potential distribution measurement and thermal imaging analysis. The breakdown state characteristics are constructed based on the breakdown current critical value, the breakdown depth, and the breakdown area ratio.

4. The method according to claim 3, characterized in that, The breakdown state characteristics, constructed based on the resistance fluctuation characteristics and temperature response curves in the initial monitoring information, are used to calculate the drift current range using a thermal effect intensity assessment method, including: Based on the breakdown current critical value, the breakdown depth and the breakdown area ratio, the power density per unit area of ​​the current transformer measurement circuit contact point is calculated. Based on the thermal effect intensity determined by the power density per unit area, the temperature field distribution characteristics are generated by scanning using infrared thermal imaging technology. The thermal resistance coefficient is calculated by analyzing the relationship between the temperature rise rate and the current intensity based on the surface temperature of the contact point collected by an infrared thermal imager under different load currents. A mathematical model of current intensity and steady-state temperature rise is constructed based on the thermal resistance coefficient. The mathematical model is used to perform predictive analysis of steady-state temperature and corresponding contact resistance change rate under each current value, thereby generating the drift current range.

5. The method according to claim 4, characterized in that, The step of calculating the adjustment amount includes: Within the drift current range, the contact resistance value is continuously monitored at a preset sampling frequency to calculate the instantaneous drift rate data sequence; The maximum value and arithmetic mean of the instantaneous drift rate data sequence within the monitoring period are statistically analyzed, and the maximum deviation of the contact resistance value from the initial stable value is recorded as the drift amplitude. In response to the drift amplitude exceeding a preset percentage of the initial resistance value or the arithmetic mean of the instantaneous drift rate exceeding a preset rate of change, the resistance value at the trigger determination time is recorded as a resistance threshold and the corresponding temperature value is recorded as a temperature threshold. Based on the resistance threshold and temperature threshold, Hertzian contact theory is applied to calculate the minimum contact pressure required to reduce the contact resistance to the threshold level at the current temperature, and the difference between the target pressure value and the current measured pressure value is used as the adjustment amount.

6. The method according to claim 5, characterized in that, The dynamic pressure adjustment module is equipped with a pressure execution unit, a pressure sensing unit, and a control unit; the application of the contact pressure adjustment amount to the contact point of the current transformer measurement circuit through the dynamic pressure adjustment module includes: The control unit receives the adjustment amount and generates a pressure control command. The pressure actuator responds to the pressure control command and generates a mechanical displacement to apply the contact pressure adjustment to the contact point of the current transformer measurement circuit. The pressure sensing unit detects the actual pressure value at the contact point in real time and transmits it to the control unit. The control unit compares the actual pressure value with the target pressure value and dynamically adjusts the pressure control command based on the difference until the actual pressure value stabilizes within the target pressure range.

7. The method according to claim 5, characterized in that, The calculation of the optimal operating current range, corresponding pressure value range, and contact resistance stability range of the current transformer measurement circuit based on the compensation monitoring information and the rated measurement current accuracy technical indicators configured in the current transformer value traceability device includes: Based on the resistance drift amplitude, drift rate and oxide layer state parameters in the compensation monitoring information, candidate current points that meet the preset stability threshold are selected within the drift current range. The measurement error corresponding to the candidate current point is compared and verified with the error limit specified in the technical specification of the accuracy of the rated measurement current to determine the effective current range that meets the accuracy requirements. Within the effective current range, the contact pressure is adjusted in a stepwise manner, the contact resistance fluctuation at each pressure point is monitored, and the pressure value at which the resistance value remains within the preset fluctuation range is recorded. The minimum current value within the effective current range is used as the lower limit of the optimal operating current range, and the maximum current value is used as the upper limit. The minimum value among the recorded pressure values ​​is used as the lower limit of the corresponding pressure value range, and the maximum value is used as the upper limit. The minimum and maximum values ​​of the contact resistance measured within the pressure value range are used as the stable range of the contact resistance.

8. A measurement system for a current transformer value traceability device, characterized in that, The measurement system is based on a multi-parameter monitoring module and a dynamic pressure adjustment module deployed in the current transformer measurement loop, including: The initial monitoring information acquisition module is used to acquire the initial monitoring information of the contact point of the current transformer measurement circuit through the multi-parameter monitoring module. The drift current range calculation module is used to calculate the drift current range based on the breakdown state characteristics constructed from the resistance fluctuation characteristics and temperature response curve in the initial monitoring information and using the thermal effect intensity evaluation method. The breakdown state characteristics are used to characterize the physical breakdown state of the oxide layer of the contact point under different load current intensities. The drift current range is used to characterize the current operating range in which the temperature rise of the contact point causes the contact resistance value to drift. A dynamic contact pressure adjustment module is used to apply a contact pressure adjustment amount to the contact point of the current transformer measurement circuit through the dynamic pressure adjustment module. The adjustment amount is calculated based on the resistance drift amplitude and drift rate obtained by real-time monitoring of the contact resistance within the drift current range. The compensation monitoring information acquisition module is used to acquire the compensation monitoring information of the current transformer measurement circuit contact point after the contact pressure adjustment amount has been applied through the multi-parameter monitoring module. The device measurement result generation module is used to calculate the optimal operating current range, corresponding pressure value range, and contact resistance stability range of the current transformer measurement circuit based on the compensation monitoring information and the rated measurement current accuracy technical indicators configured in the current transformer value traceability device.

9. An electronic device, characterized in that, include: At least one processor; and a memory that is communicatively connected to the at least one processor; The memory stores instructions that can be executed by the at least one processor to enable the at least one processor to perform the method of any one of claims 1-7.

10. A non-transitory computer-readable storage medium storing computer instructions, characterized in that, in, Computer instructions are used to cause a computer to perform the method according to any one of claims 1-7.

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