A remote self-calibration method for electromagnetic current transformer

Abstract

The present invention discloses a remote self-calibration method for an electromagnetic current transformer, which relates to the technical field of transformer calibration, and includes the following calibration method: based on calculating the calibrated current ratio output by a calibration module. The present invention has the ability to more accurately reflect the influence of temperature and other factors on the measurement accuracy by real-time monitoring of the operating status and measurement error of the current transformer and combining the calculation of the current ratio error index. At the same time, by calculating the temperature compensation coefficient and the calibrated current ratio, accurate compensation for temperature and other factors is achieved, thereby significantly improving the measurement accuracy of the current transformer. The method has remote self-calibration, which can realize remote monitoring and automatic calibration of the current transformer, and the system will automatically start the calibration process to complete the calibration work without manual intervention, which not only reduces the maintenance cost and workload, but also improves the timeliness and accuracy of calibration. The method can calculate the compensation parameters in real time, so that it has excellent adaptability.

Description

Technical Field

[0001] The invention relates to the technical field of mutual inductor calibration, and in particular to a remote self-calibration method for an electromagnetic current mutual inductor. Background Art

[0002] In the power system, electromagnetic current transformer is a key measuring device. It is widely used in current measurement and conversion, which is of great significance to the stable operation of the power system and the guarantee of power quality. Electromagnetic current transformer has the advantages of simple structure and low cost, and has been widely used in the power industry. However, with the continuous development of the power system, the requirements for the measurement accuracy of electromagnetic current transformer are getting higher and higher. Especially in an environment with large temperature changes, the measurement accuracy of electromagnetic current transformer is easily affected by temperature, resulting in increased measurement errors, affecting the stable operation of the power system, and then the electromagnetic current transformer needs to be calibrated.

[0003] However, the current existing calibration methods may be based on simplified mathematical models, which are difficult to fully and accurately reflect the actual impact of temperature on the performance of current transformers. This leads to the fact that in environments with large temperature changes, the measurement error of the current transformer may still be large, and the temperature compensation parameters in the prior art may be determined through experiments before leaving the factory and remain unchanged during use. However, with the aging of the current transformer and changes in the use environment, these fixed compensation parameters may no longer provide effective compensation effects, and most electromagnetic current transformers may lack remote self-calibration functions, requiring manual on-site calibration and maintenance on a regular basis, which not only increases maintenance costs and workload, but may also lead to accumulation of measurement errors due to untimely calibration. Summary of the invention

[0004] The purpose of the present invention is to provide a remote self-calibration method for an electromagnetic current transformer, which solves the problems raised in the above background technology.

[0005] To achieve the above object, the present invention provides the following technical solution: a remote self-calibration method for an electromagnetic current transformer, comprising the following calibration method:

[0006] Step 1: collect the primary current value, the secondary current value, the magnetizing current value of the electromagnetic current transformer and the working environment temperature value of the current transformer through a data acquisition module;

[0007] Step 2: Based on the data transmission module, the primary current value, the secondary current value, the magnetizing current value of the electromagnetic current transformer and the working environment temperature value of the current transformer are input into the calculation and calibration module;

[0008] Step 3: Based on the calculation and calibration module, the primary current value, the secondary current value, the magnetizing current value of the electromagnetic current transformer and the working environment temperature value of the current transformer are processed, and the current ratio error index, the temperature compensation coefficient and the calibrated current ratio are output;

[0009] Step 4: Based on the calibrated current ratio, the primary current value and the secondary current value are collected again through the data acquisition module, and the calibrated current ratio is used for verification to ensure that the error is within an acceptable range;

[0010] Step 5: Based on the output module, the data and calculation results of the calibration process are organized into a report for display on the display terminal, and the calibration time, calibration results, adjustment parameters and other information are recorded in the maintenance file of the current transformer.

[0011] Optionally, the calculation and calibration module includes: a current ratio error submodule, a temperature influence submodule, a summary submodule and an adjustment submodule.

[0012] Optionally, the calculation formula of the current ratio error submodule is as follows:

[0013] ;

[0014] in:

[0015] GALAP refers to the current ratio error index;

[0016] I a Refers to the primary current value, I b Refers to the secondary current value, Na refers to the rated transformation ratio of the current transformer,

[0017] TG refers to the working environment temperature of the current transformer, TA refers to the calibration reference temperature, I m refers to the magnetizing current value of the transformer, A1 refers to the coefficient of the influence of temperature on the transformation ratio, A2 refers to the correction adjustment factor, 1+A1×(TG-TA) is the adjustment factor of the influence of temperature on the transformation ratio, I b +I m Refers to the actual situation degree value of the current transformer;

[0018] The processing process of the current ratio error submodule is as follows: the primary current value I a , secondary current value I b , the working environment temperature value TG of the current transformer and the magnetizing current value I of the transformer m Substitute them together into the current ratio error submodule, and output the current ratio error index GALAP based on the coefficient A1 of the temperature effect on the transformation ratio and the correction adjustment factor A2.

[0019] Optionally, the calculation formula of the temperature impact submodule is as follows:

[0020] MLXGA=B1+[BA×(1+α×GALAP)] 2 ×(TG-TA)+B3×(TG-TA) 3 +B4×exp[(TG-TA) / TS];

[0021] in:

[0022] MLXGA refers to the temperature compensation coefficient;

[0023] TS refers to the relevant constant of the temperature compensation curve, exp refers to the exponential function, BA refers to the temperature compensation coefficient, α refers to the adjustment factor, B1 refers to the initial value of the temperature compensation coefficient, B3 refers to the coefficient of the quadratic temperature compensation term, B4 refers to the temperature compensation factor, and BA×(1+α×GALAP) refers to the coefficient of the linear temperature compensation term;

[0024] The processing process of the temperature influence submodule is as follows: the current ratio error index GALAP and the working environment temperature value TG of the current transformer are input into the temperature influence submodule, and based on the relevant constant TS and the temperature compensation coefficient BA of the temperature compensation curve, the temperature compensation coefficient MLXGA is output.

[0025] Optionally, the calculation formula of the summary submodule is as follows:

[0026] ;

[0027] in:

[0028] UZIE refers to the calibrated current ratio;

[0029] β refers to the adjustment factor of temperature compensation, γ refers to the temperature sensitivity coefficient, β×MLXGA refers to the influence value of the temperature compensation coefficient, I a / Na refers to the theoretical current ratio;

[0030] The processing process of the summary submodule is as follows: the temperature compensation coefficient MLXGA and the current ratio error index GALAP are input into the summary submodule, and based on the temperature compensation adjustment factor β and the temperature sensitivity coefficient γ, the calibrated current ratio UZIE is output.

[0031] Optionally, the processing process of the adjustment submodule is as follows:

[0032] First: A2 i+1 =A2 i +KNA×(UZIE-IY) 2 ;

[0033] Second: Set the loop convergence conditions:

[0034] Convergence condition 1: The number of iterations i is 152;

[0035] Convergence condition 2: |A2 i+1 -A2 i |<PP,PP=0.00027;

[0036] in:

[0037] A2 i+1 Refers to the correction adjustment factor after the i+1th iteration;

[0038] A2 i Refers to the correction adjustment factor after the i-th iteration;

[0039] KNA refers to the adjustment factor, IY refers to the expected current ratio, and PP refers to the iteration tolerance;

[0040] Based on the difference between the calibrated current ratio UZIE and the expected current ratio IY, the correction adjustment factor A2 after the i-th iteration is adjusted by the adjustment factor KNA i The change range is output, and the correction adjustment factor A2 after the i+1th iteration is output i+1 , the correction adjustment factor A2 after the i+1th iteration i+1 Replace the correction adjustment factor A2 in the current ratio error submodule, and then continuously influence and iterate the values ​​of the current ratio error index GALAP, the temperature compensation coefficient MLXGA and the calibrated current ratio UZIE, and terminate the convergence of the iteration of the correction adjustment factor A2 through convergence conditions one and two.

[0041] Optionally, the data acquisition module uses a high-precision current measurement device to collect the primary current value and the secondary current value of the electromagnetic current transformer, and collects the working environment temperature of the current transformer in real time through a temperature sensor.

[0042] Optionally, the data transmission module uses wireless transmission technology to transmit the primary current value, secondary current value, magnetizing current value of the electromagnetic current transformer and the working environment temperature value of the current transformer to the calculation and calibration module in the computer.

[0043] Compared with the prior art, the present invention has the following beneficial effects:

[0044] 1. The present invention calculates the current ratio error index GALAP through the current ratio error submodule. The real-time calculation of the current ratio error can instantly feedback the measurement status of the current transformer, providing a basis for subsequent calibration and adjustment. This submodule comprehensively considers multiple factors such as primary current, secondary current, rated transformation ratio, temperature influence coefficient, current temperature, reference temperature and magnetizing current, and accurately calculates the current ratio error of the current transformer, which directly reflects the measurement accuracy of the current transformer under specific working conditions. It is an important basis for subsequent calibration and adjustment, and the calculated current ratio error can timely discover and deal with potential measurement deviations.

[0045] 2. The present invention calculates the temperature compensation coefficient MLXGA through the current ratio error submodule. The calculation of the temperature compensation coefficient MLXGA can accurately reflect the impact of temperature changes on the performance of the current transformer, thereby improving the measurement stability of the equipment in different temperature environments. This submodule takes into account the impact of temperature on the performance of the current transformer, enhances the adaptability of the equipment in different environments, and dynamically adjusts the temperature compensation coefficient according to real-time temperature data to ensure the stability of the measurement accuracy. It combines intelligent algorithms and temperature sensing technology to realize automatic perception and compensation of temperature changes.

[0046] 3. The present invention calculates the calibrated current ratio UZIE through a summary submodule. The calculation of the calibrated current ratio UZIE comprehensively considers the influence of the current ratio error and the temperature compensation coefficient, thereby realizing a comprehensive calibration of the current transformer. The calibrated current ratio can more accurately reflect the actual current value, thereby improving the measurement accuracy of the current transformer. The precise calibration calculation of this submodule improves the measurement accuracy of the current transformer. The calibrated current ratio can be used as an important basis for evaluating the calibration effect and is verifiable. This remote self-calibration technology comprehensively considers various factors such as current ratio error and temperature, thereby realizing a comprehensive and accurate calibration of the current transformer. The calculation result of the calibrated current ratio reflects the comprehensiveness and accuracy of the remote self-calibration technology.

[0047] 4. The present invention uses the adjustment submodule to correct the adjustment factor A2 i By iteratively correcting the adjustment factor A2, I can be adjusted more finely. b The value of I can improve the calibration accuracy and easily adapt to the influence of different temperatures, environmental conditions and transformer aging on the current ratio. b The method can be completed remotely and automatically, which greatly simplifies the calibration process and improves efficiency. When applied to the remote self-calibration system, it does not require physical contact with the transformer, and can send calibration instructions and adjustment parameters through the network, thereby reducing maintenance costs and improving system reliability and availability. The automatic iterative correction adjustment factor A2 iThe method can more accurately match the actual current ratio and reduce errors. The calibrated transformer can measure current more accurately, which is crucial for the stable operation of the power system. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 is a flowchart of the steps of the electromagnetic current transformer remote self-calibration method;

[0049] Figure 2 Schematic diagram of the overall structure of the electromagnetic current transformer remote self-calibration method;

[0050] Figure 3 It is a structural diagram of the calculation calibration module in the remote self-calibration method of the electromagnetic current transformer. DETAILED DESCRIPTION

[0051] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0052] The electromagnetic current transformer remote self-calibration method is different from the existing remote self-calibration method. In an environment with large temperature changes, the measurement accuracy of the electromagnetic current transformer is easily affected by temperature, resulting in increased measurement errors and affecting the stable operation of the power system. Although the existing calibration method will consider the influence of temperature on the measurement accuracy and take corresponding temperature compensation measures, these temperature compensation measures are often based on certain assumptions and simplified models, and it is difficult to fully and accurately reflect the actual influence of temperature on the performance of the current transformer. In addition, with the complexity of the power system, the electromagnetic current transformer may be affected by other factors during use, such as magnetizing current, etc. These factors may also lead to increased measurement errors.

[0053] The module of the electromagnetic current transformer remote self-calibration system method can monitor the operating status and measurement error of the current transformer in real time, and combined with the current ratio error sub-module, it can more accurately reflect the influence of temperature and other factors on the measurement accuracy. At the same time, through the calculation of the temperature influence sub-module and the summary sub-module, accurate compensation for temperature and other factors is achieved, thereby significantly improving the measurement accuracy of the current transformer. The remote self-calibration method proposed in the present invention can realize remote monitoring and automatic calibration of the current transformer. When it is detected that the measurement error exceeds the preset range, the system will automatically start the calibration process and complete the calibration work without human intervention. This not only reduces maintenance costs and workload, but also improves the timeliness and accuracy of calibration.

[0054] For examples, see Figures 1 to 3 , this embodiment provides a remote self-calibration method for an electromagnetic current transformer as follows:

[0055] The data acquisition module is used to collect the primary current value, the secondary current value, the magnetizing current value of the electromagnetic current transformer and the working environment temperature value of the current transformer;

[0056] Based on the data transmission module, the primary current value, the secondary current value, the magnetizing current value of the electromagnetic current transformer and the working environment temperature value of the current transformer are input into the calculation and calibration module;

[0057] Based on the calculation and calibration module, the primary current value, the secondary current value, the magnetizing current value of the electromagnetic current transformer and the working environment temperature value of the current transformer are processed, and the current ratio error index, the temperature compensation coefficient and the calibrated current ratio are output;

[0058] Based on the calibrated current ratio, the primary current value and the secondary current value are collected again through the data acquisition module, and the calibrated current ratio is used for verification to ensure that the error is within an acceptable range;

[0059] Based on the output module, the data and calculation results of the calibration process are organized into a report for display on the display terminal, and the calibration time, calibration results, adjustment parameters and other information are recorded in the maintenance file of the current transformer;

[0060] The calculation and calibration module includes a current ratio error submodule, a temperature influence submodule, a summary submodule and an adjustment submodule.

[0061] In this embodiment, the remote self-calibration of the method can monitor the measurement performance of the current transformer in real time and make dynamic adjustments as needed, while the traditional calibration method often needs to be performed offline and has a long calibration cycle. By accurately calculating the current ratio error and dynamically adjusting the temperature compensation coefficient, the remote self-calibration method can significantly improve the measurement accuracy of the current transformer. The remote self-calibration method combines sensor technology, network communication technology and intelligent algorithms to realize intelligent operation, maintenance and management of the current transformer. By real-time monitoring of the measurement data of the current transformer and making dynamic adjustments as needed, it is ensured that the current transformer is always in the best working state. By accurately calculating the current ratio error and dynamically adjusting the temperature compensation coefficient, the measurement accuracy and stability of the current transformer are improved. The method combines intelligent algorithms and automatic control technology to realize intelligent operation, maintenance and management of the current transformer, reduce the cost of manual intervention and improve work efficiency.

[0062] In general, the current ratio error index GALAP is calculated by the current ratio error submodule, and then the system automatically evaluates whether the error is within an acceptable range. If it exceeds, it enters the next calibration process. After that, the temperature compensation coefficient MLXGA is calculated by the temperature impact submodule. Then, the system automatically applies the newly calculated temperature compensation coefficient to the measurement circuit of the current transformer through the remote control interface. Finally, the calibrated current ratio UZIE is calculated by the summary submodule. The system automatically collects the primary and secondary current data again, and uses the calibrated current ratio for verification to ensure that the error is within an acceptable range.

[0063] See also Figures 1 to 3 , the processing process of the current ratio error submodule is as follows:

[0064] ;

[0065] in:

[0066] GALAP refers to the current ratio error index;

[0067] I a Refers to the primary current value;

[0068] I b Refers to the secondary current value, the secondary current I b is the current at the output end of the current transformer. It is the primary current I a It is converted according to a certain transformation ratio Na. Ideally, the secondary current should accurately reflect the magnitude of the primary current. However, in practical applications, due to various factors, such as temperature and magnetization effect, the secondary current I b There will be some deviation in the measured value;

[0069] Na refers to the rated transformation ratio of the current transformer.

[0070] TG refers to the working environment temperature value of the current transformer;

[0071] TA refers to the calibration reference temperature value. TA is a reference temperature point used for calibration and comparison. This temperature point is usually selected under specific conditions so that there can be a unified and repeatable temperature reference when evaluating the performance of the current transformer. For example, it can be usually 25°C.

[0072] I m Refers to the magnetizing current value of the transformer, magnetizing current I mIt is the current generated by the current transformer during the magnetization process. It is not directly induced by the primary current, but is caused by the magnetization characteristics of the transformer core. The existence of the magnetization current will affect the measurement accuracy of the current transformer because it will be superimposed on the secondary current, making the measured secondary current value larger.

[0073] A1 refers to the coefficient of temperature effect on the transformation ratio, A2 refers to the correction adjustment factor, and 1+A1×(TG-TA) is the adjustment factor of temperature effect on the transformation ratio;

[0074] I b +I m Refers to the actual degree value of the current transformer. When calibrating the current transformer, we need to consider the influence of the magnetizing current on the measurement result. Therefore, when calculating the current ratio or performing error analysis, the secondary current value I b The magnetizing current value I m The sum is considered as a whole, which can more accurately reflect the actual working conditions of the current transformer, thereby improving the accuracy and reliability of calibration;

[0075] The primary current value I a , secondary current value I b , the working environment temperature value TG of the current transformer and the magnetizing current value I of the transformer m Substitute them together into the current ratio error submodule, and output the current ratio error index GALAP based on the coefficient A1 of the temperature effect on the transformation ratio and the correction adjustment factor A2.

[0076] In this embodiment: the current ratio error index GALAP represents the deviation between the actual measured current and the theoretical current. The current ratio error index GALAP directly reflects the measurement accuracy of the current transformer and is an important indicator for evaluating its performance. In the remote self-calibration system, the real-time calculation of the current ratio error can instantly feedback the measurement status of the current transformer and provide a basis for subsequent calibration and adjustment. This submodule comprehensively considers multiple factors such as primary current, secondary current, rated transformation ratio, temperature influence coefficient, current temperature, reference temperature and magnetizing current to accurately calculate the current ratio error of the current transformer. This error value directly reflects the measurement accuracy of the current transformer under specific working conditions and is an important basis for subsequent calibration and adjustment. Compared with the traditional calibration method, this remote self-calibration can calculate the current ratio error in real time. Difference, timely discover and deal with potential measurement deviations. Through precise mathematical models and algorithms, this submodule can more accurately reflect the actual measurement performance of the current transformer, improve calibration accuracy, thereby reducing manual intervention and improving calibration efficiency and accuracy. Existing technologies often rely on offline calibration or regular detection, and cannot reflect the measurement status of the current transformer in real time. The remote self-calibration technology realizes continuous monitoring and adjustment of the current transformer performance by calculating the current ratio error in real time. Real-time calculation of the current ratio error is one of the core functions of the remote self-calibration technology. It embodies the concepts of remote monitoring, real-time feedback and automatic adjustment, ensures the continuity and stability of the current transformer measurement accuracy, and accurately calculates the current ratio error as a quantitative indicator for the calibration of the current transformer, making the calibration process more scientific and accurate.

[0077] See also Figures 1 to 3 , the processing process of the temperature impact submodule is as follows:

[0078] MLXGA=B1+[BA×(1+α×GALAP)] 2 ×(TG-TA)+B3×(TG-TA) 3 +B4×exp[(TG-TA) / TS];

[0079] in:

[0080] MLXGA refers to the temperature compensation coefficient;

[0081] TS refers to the relevant constant of the temperature compensation curve, exp refers to the exponential function, BA refers to the temperature compensation coefficient, α refers to the adjustment factor, B1 refers to the initial value of the temperature compensation coefficient, and B3 refers to the coefficient of the secondary temperature compensation term;

[0082] B4 refers to the temperature compensation factor, which is used to control the value of (TG-TA) / TS;

[0083] BA×(1+α×GALAP) refers to the coefficient of the linear temperature compensation term. BA×(1+α×GALAP) reflects the linear part of the temperature compensation coefficient changing with temperature when the temperature deviates from the reference temperature.

[0084] The current ratio error index GALAP and the working environment temperature value TG of the current transformer are input into the temperature influence submodule, and the temperature compensation coefficient MLXGA is output based on the relevant constant TS and the temperature compensation coefficient BA of the temperature compensation curve.

[0085] In this embodiment, the temperature compensation coefficient MLXGA can more accurately reflect the impact of temperature changes on the performance of the current transformer, thereby improving the measurement stability of the device in different temperature environments. The initial value B1 of the temperature compensation coefficient is corrected by introducing the current ratio error index GALAP, so that the temperature compensation coefficient can more accurately reflect the impact of temperature changes on the current ratio, thereby improving the measurement stability and accuracy of the current transformer at different temperatures. By introducing the temperature variable, the impact of temperature on the current ratio error is calculated, and the temperature compensation coefficient is obtained accordingly. This coefficient is used to correct the measurement deviation caused by temperature changes and improve the measurement stability of the current transformer. This submodule takes into account the impact of temperature on the performance of the current transformer and enhances the adaptability of the device in different environments. It can dynamically adjust the temperature compensation coefficient according to real-time temperature data to ensure the stability of measurement accuracy. It also combines intelligent algorithms and temperature sensing technology to realize automatic perception and compensation of temperature changes. Compared with the temperature compensation in the prior art, it may be relatively simple or fixed and cannot fully adapt to temperature fluctuations in the actual working environment. The remote self-calibration technology achieves accurate compensation for temperature changes by dynamically calculating the temperature compensation coefficient. The dynamic calculation of the temperature compensation coefficient reflects the intelligence and flexibility of the remote self-calibration technology. It can automatically adjust the calibration parameters according to changes in the actual working environment to ensure the stability and reliability of the current transformer measurement accuracy.

[0086] See also Figures 1 to 3 , the processing of the summary submodule is as follows:

[0087] ;

[0088] in:

[0089] UZIE refers to the calibrated current ratio;

[0090] β refers to the adjustment factor of temperature compensation. By adjusting the value of β, the shape of the temperature compensation curve can be optimized to better match the actual measurement data;

[0091] γ refers to the temperature sensitivity coefficient. The performance of certain materials or structures in the current transformer will change with the change of temperature. This change can be quantified by γ. The value of γ may reflect the sensitivity of the material or structure to temperature changes, thereby affecting the change of current ratio with temperature;

[0092] β×MLXGA refers to the influence degree value of the temperature compensation coefficient;

[0093] I a / Na refers to the theoretical current ratio, that is, the theoretical current ratio without considering the temperature effect;

[0094] The temperature compensation coefficient MLXGA and the current ratio error index GALAP are input into the summary submodule, and based on the temperature compensation adjustment factor β and the temperature sensitivity coefficient γ, the calibrated current ratio UZIE is output.

[0095] In this embodiment: the calibrated current ratio UZIE comprehensively considers the influence of the current ratio error and the temperature compensation coefficient, realizes the comprehensive calibration of the current transformer, and the calibrated current ratio can more accurately reflect the actual current value, thereby improving the measurement accuracy of the current transformer. This submodule comprehensively considers the current ratio error and temperature influence, realizes the comprehensive calibration of the current transformer, and improves the measurement accuracy of the current transformer through accurate calibration calculation. The calibrated current ratio can be used as an important basis for evaluating the calibration effect, and is verifiable. Compared with the calibration method in the prior art, it may be relatively simple or unable to fully consider various influencing factors. The remote self-calibration technology realizes the comprehensive and accurate calibration of the current transformer by comprehensively considering multiple factors, such as current ratio error, temperature, etc. The calculation result of the calibrated current ratio reflects the comprehensiveness and accuracy of the remote self-calibration technology. It demonstrates the high-precision calibration effect achieved by means of real-time monitoring, accurate calculation and automatic adjustment, and further reflects the advantages and value of the remote self-calibration technology. The remote self-calibration method can calculate and verify the calibrated current ratio in real time to ensure that the current transformer always maintains high accuracy and high reliability in a complex and changeable power system.

[0096] See also Figures 1 to 3 , the processing of the adjustment submodule is as follows:

[0097] First: A2 i+1 =A2 i +KNA×(UZIE-IY) 2 ;

[0098] Second: Set the loop convergence conditions:

[0099] Convergence condition 1: The number of iterations i is 152;

[0100] Convergence condition 2: |A2i+1 -A2 i |<PP,PP=0.00027;

[0101] in:

[0102] A2 i+1 Refers to the correction adjustment factor after the i+1th iteration;

[0103] A2 i Refers to the correction adjustment factor after the i-th iteration;

[0104] KNA refers to the adjustment factor, IY refers to the expected current ratio, and PP refers to the iteration tolerance;

[0105] Based on the difference between the calibrated current ratio UZIE and the expected current ratio IY, the correction adjustment factor A2 after the i-th iteration is adjusted by the adjustment factor KNA i The change range is output, and the correction adjustment factor A2 after the i+1th iteration is output i+1 , the correction adjustment factor A2 after the i+1th iteration i+1 Replace the correction adjustment factor A2 in the current ratio error submodule, and then continuously influence and iterate the values ​​of the current ratio error index GALAP, the temperature compensation coefficient MLXGA and the calibrated current ratio UZIE, and terminate the convergence of the iteration of the correction adjustment factor A2 through convergence conditions one and two.

[0106] In this embodiment: Since the secondary current value I b Iteration may be limited by measurement noise and instrument accuracy, and then the adjustment factor A2 can be adjusted more finely by iterative correction. b The value of A2 can improve the calibration accuracy. Since A2 is a continuously adjustable parameter, it can be adjusted within a small range to meet different calibration requirements. b , can more easily adapt to the influence of different temperature, environmental conditions and transformer aging on the current ratio, so I b It can be used as a compensation factor to correct the errors caused by these external factors. Compared with the traditional method, which may require multiple manual adjustments and re-measurements, the iterative I b The method can be completed remotely and automatically, which greatly simplifies the calibration process and improves efficiency. In addition, when applied to the remote self-calibration system, it does not require physical contact with the transformer, but only needs to send calibration instructions and adjust parameters through the network, which reduces maintenance costs and improves system reliability and availability. Compared with the method of directly adjusting hardware parameters or relying on fixed calibration curves, the automatic iteration I bThe method can more accurately match the actual current ratio and reduce errors. The calibrated transformer can measure current more accurately, which is crucial for the stable operation of the power system. Through regular calibration, the error of the transformer can be discovered and corrected in time to avoid damage to the equipment caused by accumulated errors in long-term operation. Accurate current measurement is the basis of power system protection and control. The calibrated transformer can improve the reliability of the entire system.

[0107] In the specific implementation process, the multiple sub-modules in the method are used to form an electromagnetic current transformer remote self-calibration system, and the primary current value I a , secondary current value I b , the working environment temperature value TG of the current transformer and the magnetizing current value I of the transformer m Substitute them together into the current ratio error submodule, and output the current ratio error index GALAP. In the remote self-calibration system, the real-time calculation of the current ratio error can immediately feedback the measurement status of the current transformer, providing a basis for subsequent calibration adjustments. This submodule comprehensively considers multiple factors such as primary current, secondary current, rated transformation ratio, temperature influence coefficient, current temperature, reference temperature and magnetizing current, and accurately calculates the current ratio error of the current transformer. This error value directly reflects the measurement accuracy of the current transformer under specific working conditions and is an important basis for subsequent calibration and adjustment. This remote self-calibration can calculate the current ratio error in real time, and promptly discover and handle potential measurement deviations. Through precise mathematical models and algorithms, this submodule can more accurately reflect the actual measurement performance of the current transformer, improve calibration accuracy, thereby reducing manual intervention and improving calibration efficiency and accuracy.

[0108] The current ratio error index GALAP and the working environment temperature value TG of the current transformer are input into the temperature influence submodule, and the temperature compensation coefficient MLXGA is output. The calculation of the temperature compensation coefficient MLXGA can more accurately reflect the influence of temperature changes on the performance of the current transformer, thereby improving the measurement stability of the equipment in different temperature environments. This submodule considers the influence of temperature on the performance of the current transformer, enhances the adaptability of the equipment in different environments, and can dynamically adjust the temperature compensation coefficient according to the real-time temperature data, ensuring the stability of the measurement accuracy. It also combines intelligent algorithms and temperature sensing technology to realize automatic perception and compensation of temperature changes.

[0109] The temperature compensation coefficient MLXGA and the current ratio error index GALAP are input into the summary submodule, and the calibrated current ratio UZIE is output. The calculation of the calibrated current ratio UZIE comprehensively considers the influence of the current ratio error and the temperature compensation coefficient, and realizes the comprehensive calibration of the current transformer. The calibrated current ratio can more accurately reflect the actual current value, thereby improving the measurement accuracy of the current transformer. This submodule improves the measurement accuracy of the current transformer through accurate calibration calculation. The calibrated current ratio is verifiable as an important basis for evaluating the calibration effect. This remote self-calibration technology realizes comprehensive and accurate calibration of the current transformer by comprehensively considering multiple factors, such as current ratio error and temperature. The calculation result of the calibrated current ratio reflects the comprehensiveness and accuracy of the remote self-calibration technology.

[0110] Correction adjustment factor A2 based on the calibrated current ratio UZIE i By iteratively correcting the adjustment factor A2, I can be adjusted more finely. b The value of I can be used to improve the calibration accuracy and easily adapt to the influence of different temperature, environmental conditions and transformer aging on the current ratio. b The method can be completed remotely and automatically, which greatly simplifies the calibration process and improves efficiency. In addition, it does not require physical contact with the transformer when applied to the remote self-calibration system. It only needs to send calibration instructions and adjustment parameters through the network, which reduces maintenance costs and improves system reliability and availability. The automatic iterative correction adjustment factor A2 i The method can more accurately match the actual current ratio and reduce errors. The calibrated transformer can measure the current more accurately, which is crucial for the stable operation of the power system. It enables the overall multiple sub-modules to cooperate with each other in calculations, and can also perform overall cycles and iterations, so that the overall system has the effect of automatic optimization and updating, and thus better adaptability.

[0111] See also Figure 1 , Figure 2 and Figure 3 The data acquisition module uses a high-precision current measurement device to collect the primary current value and secondary current value of the electromagnetic current transformer, and uses a temperature sensor to collect the working environment temperature of the current transformer in real time. The data transmission module uses wireless transmission technology to transmit the primary current value, secondary current value, magnetizing current value of the electromagnetic current transformer and the working environment temperature value of the current transformer to the calculation and calibration module in the computer.

[0112] In this embodiment, the high-precision current measuring device includes: a Hall effect sensor, a shunt and a flux meter, etc. The wireless transmission technology can adopt the LoRa wide area network remote transmission technology: LoRa is suitable for long-distance, low-power wireless transmission, and is particularly suitable for remote monitoring and Internet of Things applications.

[0113] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A remote self-calibration method for an electromagnetic current transformer, characterized in that: The following calibration methods are included: Step 1: collect the primary current value, the secondary current value, the magnetizing current value of the electromagnetic current transformer and the working environment temperature value of the current transformer through a data acquisition module; Step 2: Based on the data transmission module, the primary current value, the secondary current value, the magnetizing current value of the electromagnetic current transformer and the working environment temperature value of the current transformer are input into the calculation and calibration module; Step 3: Based on the calculation and calibration module, the primary current value, the secondary current value, the magnetizing current value of the electromagnetic current transformer and the working environment temperature value of the current transformer are processed, and the current ratio error index, the temperature compensation coefficient and the calibrated current ratio are output; Step 4: Based on the calibrated current ratio, the primary current value and the secondary current value are collected again through the data acquisition module, and the calibrated current ratio is used for verification to ensure that the error is within an acceptable range; Step 5: Based on the output module, the data and calculation results of the calibration process are organized into a report for display on the display terminal, and the information of the calibration time, calibration results, and adjustment parameters are recorded in the maintenance file of the current transformer; The calculation and calibration module includes a current ratio error submodule, a temperature influence submodule, a summary submodule and an adjustment submodule; The calculation formula of the current ratio error submodule is as follows: ； in: GALAP refers to the current ratio error index; I a Refers to the primary current value, I b Refers to the secondary current value, Na refers to the rated transformation ratio of the current transformer, TG refers to the working environment temperature of the current transformer, TA refers to the calibration reference temperature, I m refers to the magnetizing current value of the transformer, A1 refers to the coefficient of the influence of temperature on the transformation ratio, A2 refers to the correction adjustment factor, 1+A1×(TG-TA) is the adjustment factor of the influence of temperature on the transformation ratio, I b +I m Refers to the actual situation degree value of the current transformer; The processing process of the current ratio error submodule is as follows: The primary current value I a , secondary current value I b , the working environment temperature value TG of the current transformer and the magnetizing current value I of the transformer m Substitute them together into the current ratio error submodule, and output the current ratio error index GALAP based on the coefficient A1 of the temperature effect on the transformation ratio and the correction adjustment factor A2.

2. The electromagnetic current transformer remote self-calibration method according to claim 1, characterized in that: The calculation formula of the temperature impact submodule is as follows: MLXGA=B1+[BA×(1+α×GALAP)] 2 ×(TG-TA)+B3×(TG-TA) 3 +B4×exp[(TG-TA) / TS]; in: MLXGA refers to the temperature compensation coefficient; TS refers to the relevant constant of the temperature compensation curve, exp refers to the exponential function, BA refers to the temperature compensation coefficient, α refers to the adjustment factor, B1 refers to the initial value of the temperature compensation coefficient, B3 refers to the coefficient of the quadratic temperature compensation term, B4 refers to the temperature compensation factor, and BA×(1+α×GALAP) refers to the coefficient of the linear temperature compensation term; The processing process of the temperature influence submodule is as follows: the current ratio error index GALAP and the working environment temperature value TG of the current transformer are input into the temperature influence submodule, and based on the relevant constant TS and the temperature compensation coefficient BA of the temperature compensation curve, the temperature compensation coefficient MLXGA is output.

3. The electromagnetic current transformer remote self-calibration method according to claim 2, characterized in that: The calculation formula of the summary submodule is as follows: ； in: UZIE refers to the calibrated current ratio; β refers to the adjustment factor of temperature compensation, γ refers to the temperature sensitivity coefficient, β×MLXGA refers to the influence value of the temperature compensation coefficient, I a / Na refers to the theoretical current ratio; The processing process of the summary submodule is as follows: The temperature compensation coefficient MLXGA and the current ratio error index GALAP are input into the summary submodule, and based on the temperature compensation adjustment factor β and the temperature sensitivity coefficient γ, the calibrated current ratio UZIE is output.

4. The electromagnetic current transformer remote self-calibration method according to claim 3, characterized in that: The processing process of the adjustment submodule is as follows: First: A2 i+1 =A2 i +KNA×(UZIE-IY) 2 ; Second: Set the loop convergence conditions: Convergence condition 1: The number of iterations i is 152; Convergence condition 2: |A2 i+1 -A2 i |<PP,PP=0.00027; in: A2 i+1 Refers to the correction adjustment factor after the i+1th iteration; A2 i Refers to the correction adjustment factor after the i-th iteration; KNA refers to the adjustment factor, IY refers to the expected current ratio, and PP refers to the iteration tolerance; Based on the difference between the calibrated current ratio UZIE and the expected current ratio IY, the correction adjustment factor A2 after the i-th iteration is adjusted by the adjustment factor KNA i The change range is output, and the correction adjustment factor A2 after the i+1th iteration is output i+1 , the correction adjustment factor A2 after the i+1th iteration i+1 Replace the correction adjustment factor A2 in the current ratio error submodule, and then continuously influence and iterate the values ​​of the current ratio error index GALAP, the temperature compensation coefficient MLXGA and the calibrated current ratio UZIE, and terminate the convergence of the iteration of the correction adjustment factor A2 through convergence conditions one and two.

5. The electromagnetic current transformer remote self-calibration method according to claim 1, characterized in that: The data acquisition module uses a high-precision current measurement device to collect the primary current value and the secondary current value of the electromagnetic current transformer, and uses a temperature sensor to collect the working environment temperature of the current transformer in real time.

6. The electromagnetic current transformer remote self-calibration method according to claim 1, characterized in that: The data transmission module uses wireless transmission technology to transmit the primary current value, the secondary current value, the magnetizing current value of the electromagnetic current transformer and the working environment temperature value of the current transformer to the calculation and calibration module in the computer.

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