CT thermal stability verification and dynamic parameter comparative analysis system

Abstract

The invention discloses a CT thermal stability verification and dynamic parameter comparative analysis system, and belongs to the technical field of current transformers. The CT thermal stability verification and dynamic parameter comparison analysis system comprises a data acquisition module, a calculation module, a comparison module and a verification analysis module. According to the invention, the problem that the accuracy and reliability of a measurement result are influenced by measurement errors easily caused by temperature change in the prior art is solved, the performance of the CT equipment in a high-temperature environment can be evaluated, equipment damage or failure caused by overheating is avoided, and the reliability of the CT equipment is improved. The method can help to detect parameter changes of the CT equipment in different working states, timely discover potential safety hazards, ensure the measurement precision and stability of the CT equipment at various temperatures, avoid measurement errors caused by temperature changes, ensure the accuracy and reliability of measurement results, timely discover the problems of aging and performance reduction of the equipment, and improve the measurement accuracy and reliability of the CT equipment. Therefore, a reasonable maintenance plan is made.

Description

Technical Field

[0001] The present invention relates to the technical field of current transformers, and specifically to a CT thermal stability verification and dynamic parameter comparison and analysis system. Background Art

[0002] CT devices are important components used to measure, protect, and monitor electrical equipment. They are widely used in power systems and are extremely important electrical equipment. With the increase in switching frequency, the research on the dynamic characteristics of CT devices has become increasingly important.

[0003] Chinese Patent with publication number CN104267271B discloses a circuit and method for quickly obtaining dynamic parameters of power electronic devices. The circuit mainly includes: a DC power supply, a bus capacitor, a multi-pulse signal driving board, a diode, a power electronic device, a load inductor, a current transformer, and an oscilloscope. The method mainly changes the double-pulse test in the national standard to a multi-pulse test in which the width of each pulse, the high and low level durations, and the number of pulses are all adjustable. By measuring the voltage and current across the power electronic device and the multi-pulse signal waveform, it is possible to obtain the waveforms of multiple turn-on and turn-off processes and the dynamic parameters under different currents in one experiment, and it can be artificially adjusted according to the current to be measured.

[0004] In the actual use process of the above patent, if the temperature changes, it is easy to cause measurement errors, which in turn affect the accuracy and reliability of the measurement results. Therefore, it does not meet the existing requirements, and for this reason, we propose a CT thermal stability verification and dynamic parameter comparison and analysis system. Summary of the Invention

[0005] The purpose of the present invention is to provide a CT thermal stability verification and dynamic parameter comparison and analysis system, which can evaluate the performance of CT devices in high-temperature environments, avoid equipment damage or failures caused by overheating, can help detect parameter changes of CT devices in different working states, timely discover potential safety hazards, can ensure the measurement accuracy and stability of CT devices at various temperatures, avoid measurement errors caused by temperature changes, ensure the accuracy and reliability of measurement results, and through regular thermal stability verification and dynamic parameter comparison and analysis, can timely discover equipment aging and performance degradation problems, so as to formulate reasonable maintenance and repair plans and extend the service life of the equipment, solving the problems raised in the above background art.

[0006] To achieve the above purpose, the present invention provides the following technical solution: A CT thermal stability verification and dynamic parameter comparison and analysis system, including:

[0007] A data acquisition module, used to acquire the short-time thermal stability current marked on the nameplate of the CT device and the key parameters of the CT device during operation. The key parameters include: rated current, rated voltage, and temperature rise parameter;

[0008] A calculation module for calculating the steady-state value and the impact value of the short-circuit current and calculating the calorific value using the Joule's law formula;

[0009] A comparison module for comparing the calculated short-circuit current with the short-time thermal stability current marked on the nameplate of the CT device;

[0010] A verification and analysis module for simulating the actual working conditions of the CT device and the mechanical vibration during operation, testing the current value of the CT device according to the simulation results, and analyzing the thermal stability verification and dynamic parameters using the test data.

[0011] Preferably, the calculation module includes:

[0012] A steady-state value calculation unit for measuring and analyzing the current waveform after the short circuit of the CT device and calculating the steady-state value of the short-circuit current using the current waveform;

[0013] An impact value calculation unit for measuring the current waveform when the CT device is short-circuited, determining the maximum instantaneous peak value, and calculating the impact value of the short-circuit current using the maximum instantaneous peak value;

[0014] A heat calculation unit for obtaining the values of the current I, resistance R, and time t of the CT device and calculating the calorific value of the CT device using the Joule's law formula.

[0015] Preferably, the comparison module includes:

[0016] Comparing the calculated short-circuit current with the short-time thermal stability current marked on the nameplate of the CT device to obtain a deviation rate;

[0017] Setting an allowable range for the deviation rate, comparing the deviation rate with the allowable range, if it exceeds the allowable range, adjusting the temperature compensation mechanism, and calibrating the mechanical deformation caused by thermal expansion according to the deviation rate.

[0018] Preferably, the adjustment of the temperature compensation mechanism includes:

[0019] When the deviation rate corresponding to the short-time thermal stability current marked on the nameplate of the CT device exceeds the allowable range, determining the exceeding ratio of the deviation rate exceeding the allowable range;

[0020] Comparing the exceeding ratio of the deviation rate exceeding the allowable range with a preset ratio reference value;

[0021] When the exceeding ratio of the deviation rate exceeding the allowable range exceeds the preset ratio reference value, retrieving the preset steady-state value reference value and impact value reference value;

[0022] Obtain the steady-state deviation rate of the short-circuit current relative to the reference value of the steady-state value by using the difference between the steady-state value of the short-circuit current and the reference value of the steady-state value;

[0023] Obtain the impulse deviation rate of the short-circuit current relative to the reference value of the impulse value by using the difference between the impulse value of the short-circuit current and the reference value of the impulse value;

[0024] Adjust the temperature compensation mechanism by using the steady-state deviation rate and the impulse deviation rate of the short-circuit current in combination with the deviation rate corresponding to the short-time thermal stability current marked on the nameplate of your current CT device.

[0025] Preferably, adjusting the temperature compensation mechanism by using the steady-state deviation rate and the impulse deviation rate of the short-circuit current in combination with the deviation rate corresponding to the short-time thermal stability current marked on the nameplate of your current CT device includes:

[0026] Compare the impulse deviation rate of the short-circuit current with the deviation rate corresponding to the short-time thermal stability current marked on the nameplate of your current CT device to obtain a first comparison result;

[0027] Compare the steady-state deviation rate of the short-circuit current with the deviation rate corresponding to the short-time thermal stability current marked on the nameplate of your current CT device to obtain a second comparison result;

[0028] When the first comparison result indicates that the impulse deviation rate of the short-circuit current exceeds the deviation rate corresponding to the short-time thermal stability current marked on the nameplate of your current CT device, or when the second comparison result indicates that the steady-state deviation rate of the short-circuit current exceeds the deviation rate corresponding to the short-time thermal stability current marked on the nameplate of your current CT device, then retrieve the preset initial temperature compensation coefficient;

[0029] Retrieve the current maximum local temperature and minimum local temperature of the CT device;

[0030] Perform a difference process on the maximum local temperature and the minimum local temperature to obtain the current local temperature difference value of the CT device;

[0031] Adjust the initial temperature compensation coefficient by using the local temperature difference value in combination with the impulse deviation rate, the steady-state deviation rate, and the deviation rate corresponding to the short-time thermal stability current marked on the nameplate of your current CT device to obtain the adjusted temperature compensation coefficient.

[0032] Preferably, the verification and analysis module includes:

[0033] A setting unit for setting the test parameters of the CT device, and the test parameters include: line number, phase, PT number, winding number, rated secondary voltage, level, current temperature, rated frequency, maximum test voltage, and maximum test current parameters;

[0034] A test unit, which is used to simulate the actual working conditions of a CT device and the mechanical vibration during operation, test the current of the CT device, and collect test data;

[0035] An analysis unit, which is used to export test data and analyze the thermal stability verification and dynamic parameters of the CT device by using the test data.

[0036] Preferably, the test unit includes:

[0037] Simulate the actual working conditions of the CT device and the mechanical vibration during operation by using test parameters;

[0038] Test the current of the CT device by using the simulated actual working conditions of the CT device and the mechanical vibration during operation

[0039] Connect the test wire to the CT device and test the current of the CT device by using test parameters;

[0040] Collect the device response test data under the dynamic parameters of the CT device, record the mechanical stability test indexes of the CT device under vibration conditions, and transmit the test results to the analysis unit;

[0041] Preferably, the analysis unit specifically includes:

[0042] Measure the core parameters of the thermal stability verification of the CT device in real time, compare the core parameters of the thermal stability verification measured in real time with the test data, and analyze the secondary winding resistance and heat capacity;

[0043] Correlate the impact value of the short-circuit current with the test data, and obtain the dynamic stability multiple of the CT device by using the ratio of the impact value of the short-circuit current to the rated current;

[0044] Verify the dynamic stability multiple and the impact current of the CT device and analyze the dynamic response characteristics;

[0045] Conduct correlation analysis on the test data and standard parameters, compare the error curve with the standard limit value, and combine the short-circuit current duration and the time constant of the CT device to evaluate whether the thermal accumulation of the CT device under short-term overload is controllable;

[0046] If it is found through comparison that the thermal stability or dynamic parameters do not meet the standards, dynamically adjust the verification frequency according to the change trend of the test data.

[0047] Preferably, the comparison of the core parameters of the thermal stability verification measured in real time with the test data and the analysis of the secondary winding resistance and heat capacity specifically include:

[0048] Compare the effective value and duration of the short-circuit current measured by the CT device with the effective value and duration of the current marked on the nameplate of the CT device to verify whether it meets the thermal stability threshold;

[0049] After correcting the resistance of the secondary winding of the CT device in combination with the ambient temperature, calculate whether the heat capacity loss of the CT device is consistent with the theoretical value.

[0050] Preferably, the verification of the dynamic stability multiple and the impact current and the analysis of the dynamic response characteristics specifically include:

[0051] Compare the peak value of the measured short-circuit impact current of the CT device with the peak value of the short-circuit impact current marked on the nameplate of the CT device to determine whether the CT device can withstand the instantaneous mechanical stress, and obtain the verification result of the verification of the dynamic stability multiple and the impact current;

[0052] Obtain the frequency response characteristics of the CT device, compare the dynamic errors under different current amplitudes, and obtain the analysis of the dynamic response characteristics.

[0053] Compared with the prior art, the beneficial effects of the present invention are:

[0054] Through thermal stability verification, the present invention can evaluate the performance of the CT device in a high-temperature environment, ensure that it can still work normally under extreme conditions, and avoid equipment damage or failure caused by overheating. The comparison and analysis of dynamic parameters can help detect the parameter changes of the CT device under different working conditions, and timely discover potential safety hazards. Thermal stability verification can ensure the measurement accuracy and stability of the CT device at various temperatures, and avoid measurement errors caused by temperature changes. The comparison and analysis of dynamic parameters can verify the parameter consistency of the CT device under different working conditions, and ensure the accuracy and reliability of the measurement results. By regularly performing thermal stability verification and comparison and analysis of dynamic parameters, the problems of equipment aging and performance degradation can be discovered in time, so as to formulate a reasonable maintenance and maintenance plan and extend the service life of the equipment. Brief Description of the Drawings

[0055] Figure 1 It is a schematic diagram of the CT thermal stability verification and dynamic parameter comparison and analysis system of the present invention;

[0056] Figure 2 It is a flow chart of the CT thermal stability verification and dynamic parameter comparison and analysis system of the present invention. Detailed Embodiments

[0057] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work shall fall within the protection scope of the present invention.

[0058] In order to solve the problem that in the actual use process of the existing technology, if the temperature changes, it is easy to cause measurement errors, which in turn affects the accuracy and reliability of the measurement results, please refer to Figure 1 - Figure 2 , the following technical solutions are provided in this embodiment:

[0059] A CT thermal stability verification and dynamic parameter comparison and analysis system, including:

[0060] A data acquisition module, which is used to acquire the short-time thermal stability current marked on the CT device nameplate and the key parameters of the CT device operation. The key parameters include: rated current, rated voltage, and temperature rise parameter;

[0061] A calculation module, which is used to calculate the steady-state value and impulse value of the short-circuit current and calculate the heat generation using the Joule's law formula to ensure that the current and the energization time will not cause overheating when the internal resistance of the CT device is certain;

[0062] A comparison module, which is used to compare the calculated short-circuit current with the short-time thermal stability current marked on the CT device nameplate, such as the 1-second or 3-second thermal stability current;

[0063] A verification and analysis module, which is used to simulate the actual working conditions of the CT device and the mechanical vibration during operation, test the current of the CT device according to the simulation results, analyze the thermal stability verification and dynamic parameters using the test data, optimize the CT device selection, layout method and protection configuration through the comparison results, improve the economy and safety of the system, ensure the safe operation of the device under short-circuit faults by quantitatively evaluating the thermal stability and dynamic stability, and provide data support for system design, protection configuration and operation and maintenance decisions.

[0064] The calculation module includes:

[0065] A steady-state value calculation unit, which is used to measure and analyze the current waveform after the CT device is short-circuited and calculate the steady-state value of the short-circuit current using the current waveform;

[0066] An impulse value calculation unit, which is used to measure the current waveform when the CT device is short-circuited, determine the maximum instantaneous peak value, and calculate the impulse value of the short-circuit current using the maximum instantaneous peak value;

[0067] A heat calculation unit, which is used to obtain the values of the current I, resistance R, and time t of the CT device and calculate the heat generation of the CT device using the Joule's law formula;

[0068] By calculating the calorific value, the temperature distribution of the CT device under different working conditions can be predicted, potential thermal risks can be detected in a timely manner, and corresponding protective measures can be taken to avoid overheating and damage of the device. A reasonable thermal stability design can reduce the probability of device damage caused by overheating, extend the service life of the device, and reduce maintenance costs. As a part of the power system, the thermal stability of the CT device has an important impact on the operation of the entire system. Through thermal stability calculation, it can be ensured that the CT device remains stable even in the event of a fault, reducing the occurrence of system faults.

[0069] A comparison module, including:

[0070] Compare the calculated short-circuit current with the short-time thermal stability current marked on the CT device nameplate to obtain the deviation rate;

[0071] Set the allowable range of the deviation rate, compare the deviation rate with the allowable range. If it exceeds the allowable range, such as ±5%, adjust the temperature compensation mechanism and calibrate the mechanical deformation caused by thermal expansion according to the deviation rate.

[0072] Specifically, the adjustment of the temperature compensation mechanism includes:

[0073] When the deviation rate corresponding to the short-time thermal stability current marked on the CT device nameplate exceeds the allowable range, determine the exceeding ratio of the deviation rate exceeding the allowable range;

[0074] Compare the exceeding ratio of the deviation rate exceeding the allowable range with a preset ratio reference value;

[0075] When the exceeding ratio of the deviation rate exceeding the allowable range exceeds the preset ratio reference value, retrieve the preset steady-state value reference value and impulse value reference value;

[0076] Use the difference between the steady-state value of the short-circuit current and the steady-state value reference value to obtain the steady-state deviation rate of the steady-state value of the short-circuit current compared to the steady-state value reference value;

[0077] Use the difference between the impulse value of the short-circuit current and the impulse value reference value to obtain the impulse deviation rate of the impulse value of the short-circuit current compared to the impulse value reference value;

[0078] Adjust the temperature compensation mechanism by combining the steady-state deviation rate and impulse deviation rate of the short-circuit current with the deviation rate corresponding to the short-time thermal stability current marked on the current CT device nameplate.

[0079] The technical effects of the above technical solution are as follows: First, when the deviation rate corresponding to the short-time thermal stability current exceeds the allowable range, calculate and determine the exceeding ratio of the deviation rate exceeding the allowable range. This step is to preliminarily evaluate the current current state and find out the degree to which the deviation exceeds the allowable range. Compare the calculated exceeding ratio with the preset ratio reference value. Through this comparison operation, judge whether the current deviation degree has reached the standard that requires further processing. If the exceeding ratio exceeds the preset ratio reference value, it indicates that the deviation situation is relatively serious. At this time, retrieve the preset steady-state value reference value and impulse value reference value. These reference values are the basic data for subsequent more detailed deviation analysis. Calculate the steady-state deviation rate of the short-circuit current compared with the steady-state value reference value (using the difference between the two), and the impulse deviation rate of the short-circuit current compared with the impulse value reference value (also using the difference between the two). This step deeply analyzes the differences between the short-circuit current and the reference values in terms of steady state and impulse. Finally, adjust the temperature compensation mechanism by comprehensively considering the steady-state deviation rate, impulse deviation rate of the short-circuit current, and the deviation rate corresponding to the short-time thermal stability current marked on the nameplate of your current CT device. By comprehensively considering multiple deviation factors, achieve precise adjustment of the temperature compensation mechanism to adapt to different current deviation situations.

[0080] By comprehensively considering the steady-state deviation rate, impulse deviation rate of the short-circuit current, and the deviation rate of the short-time thermal stability current, it can more comprehensively reflect the actual situation of the system under different states, thus making the adjustment of the temperature compensation mechanism more precise, avoiding the problem of inaccurate compensation caused by a single deviation factor, and improving the accuracy and reliability of temperature compensation. Timely and accurate adjustment of the temperature compensation mechanism can better cope with the impact brought by current deviation and ensure the stable operation of the system under abnormal current conditions. For example, when the current deviation is large, reasonable adjustment of temperature compensation can prevent damage to system equipment caused by abnormal temperature rise or fall, thus enhancing the stability and safety of the system. Precise temperature compensation helps to maintain the normal working temperature of system equipment, reduce the impact of temperature fluctuations on equipment performance, and thus improve the overall performance of the system. For example, for some temperature-sensitive electronic components or equipment, accurate temperature compensation can ensure the stability and consistency of their performance and improve the working efficiency and reliability of the system. This technical solution can be flexibly adjusted according to different current deviation situations and has good adaptability to various complex working conditions and current changes. Whether it is the deviation of steady-state current or impulse current, the temperature compensation mechanism can be adjusted through corresponding calculations and comparisons to ensure that the system can maintain a good operating state under different conditions. By timely monitoring of current deviation and adjustment of the temperature compensation mechanism, it is possible to prevent equipment failures caused by abnormal temperature to a certain extent. Compensate and adjust the temperature in advance to avoid damage to equipment due to overheating or overcooling, extend the service life of equipment, and reduce the maintenance cost and failure risk of the system.

[0081] Specifically, the temperature compensation mechanism is adjusted by combining the steady-state deviation rate and the impact deviation rate of the short-circuit current with the deviation rate corresponding to the short-time thermal stability current marked on the current CT device nameplate, including:

[0082] Compare the impact deviation rate of the short-circuit current with the deviation rate corresponding to the short-time thermal stability current marked on the current CT device nameplate to obtain a first comparison result;

[0083] Compare the steady-state deviation rate of the short-circuit current with the deviation rate corresponding to the short-time thermal stability current marked on the current CT device nameplate to obtain a second comparison result;

[0084] When the first comparison result indicates that the impact deviation rate of the short-circuit current exceeds the deviation rate corresponding to the short-time thermal stability current marked on the current CT device nameplate, or the second comparison result indicates that the steady-state deviation rate of the short-circuit current exceeds the deviation rate corresponding to the short-time thermal stability current marked on the current CT device nameplate, then call the preset initial temperature compensation coefficient;

[0085] Retrieve the current maximum local temperature and minimum local temperature of the CT device;

[0086] Perform a difference process using the maximum local temperature and the minimum local temperature to obtain the current local temperature difference value of the CT device;

[0087] Adjust the initial temperature compensation coefficient by combining the local temperature difference value with the impact deviation rate, steady-state deviation rate, and the deviation rate corresponding to the short-time thermal stability current marked on the current CT device nameplate to obtain the adjusted temperature compensation coefficient;

[0088] Among them, the adjusted temperature compensation coefficient is obtained through the following formula:

[0089]

[0090] Among them, W represents the adjusted temperature compensation coefficient; W0 represents the temperature compensation coefficient before adjustment; p w and p c represent the steady-state deviation rate and the impact deviation rate respectively; P I represents the deviation rate corresponding to the short-time thermal stability current marked on the current CT device nameplate; T avg represents the average temperature rise gradient of the CT device; ΔT represents the local temperature difference value. Specifically, max(p w -p I ,p c -p I ) calculates the steady-state deviation rate p w , the impact deviation rate p cThe deviation rate p corresponding to the short-time thermal stability current marked on the nameplate of your current CT device I The maximum value in the difference. This step is to measure the deviation degrees of the steady-state deviation and the impact deviation relative to the short-time thermal stability current marked on the nameplate of your current CT device, and the larger deviation degree is used to characterize the main influencing factor of the current deviation on temperature compensation. If the deviation degree of the steady-state deviation rate is large, the steady-state deviation is the dominant factor; if the deviation degree of the impact deviation rate is large, the impact deviation is the dominant factor. max(p w , p c ) takes the larger value between the steady-state deviation rate p w and the impact deviation rate p c as a normalized benchmark. Divide the deviation difference in the numerator by the larger deviation rate in the denominator to obtain a relative ratio value, which reflects the proportion of the deviation degree in the overall deviation and is used to measure the relative importance of the deviation. The Sigmoid function in is a non-linear function with a value range between (0, 1). T avg is the average temperature rise gradient of the CT device, and ΔT is the local temperature difference value. When the average temperature rise gradient T avg is larger relative to the local temperature difference value ΔT, -T avg / ΔT is smaller, and the Sigmoid function value approaches 0; conversely, the Sigmoid function value approaches 1. It is used here to introduce a non-linear adjustment mechanism to non-linearly adjust the temperature compensation coefficient according to the relationship between the average temperature rise gradient of the device and the local temperature difference. For example, if the average temperature rise gradient is large but the local temperature difference is small, it means that the overall temperature rises quickly but the distribution is relatively uniform, the Sigmoid function value is small, and the adjustment amplitude of the temperature compensation coefficient is small; if the average temperature rise gradient is small but the local temperature difference is large, it means that the temperature rises slowly but the distribution is uneven, the Sigmoid function value is large, and the adjustment amplitude of the temperature compensation coefficient is large. In the overall formula above, W0 is the initial temperature compensation coefficient. On this basis, combined with the relative deviation degree of the current deviation (the operation result of the numerator and denominator) and the non-linear adjustment related to the device temperature distribution (the result of the Sigmoid function), the initial temperature compensation coefficient is adjusted to obtain the adjusted temperature compensation coefficient W. That is, the appropriate temperature compensation coefficient is determined by comprehensively considering the current deviation and the device temperature state to meet the temperature adjustment requirements under different operating conditions.

[0091] The technical effects of the above technical solution are as follows: The impact deviation rate and the steady-state deviation rate of the short-circuit current are respectively compared with the deviation rate corresponding to the short-time thermal stability current marked on your current CT device nameplate, obtaining the first comparison result and the second comparison result. Through this comparison, the relative magnitude relationship between the deviation of the short-circuit current in terms of impact and steady state and the deviation of the short-time thermal stability current is judged to determine whether it is necessary to adjust the temperature compensation mechanism and the direction of adjustment. When the impact deviation rate exceeds the deviation rate corresponding to the short-time thermal stability current, or the steady-state deviation rate exceeds the deviation rate corresponding to the short-time thermal stability current, it indicates that the current deviation situation is relatively special and intervention in temperature compensation is required. At this time, the preset initial temperature compensation coefficient is retrieved. This initial coefficient is the basis for subsequent temperature compensation adjustment. The current maximum local temperature and minimum local temperature of the CT device are obtained. These two temperature values reflect the extreme conditions of the internal temperature distribution of the CT device, providing data support for calculating the local temperature difference. The difference between the maximum local temperature and the minimum local temperature is processed to obtain the current local temperature difference value of the CT device. This value reflects the degree of non-uniformity of the internal temperature distribution of the CT device and is an important factor for adjusting the temperature compensation coefficient. Considering comprehensively the local temperature difference value, the impact deviation rate, the steady-state deviation rate, and the deviation rate corresponding to the short-time thermal stability current marked on your current CT device nameplate, the initial temperature compensation coefficient is adjusted to obtain the adjusted temperature compensation coefficient. Through this multi-factor comprehensive adjustment method, the temperature compensation coefficient can be accurately adjusted according to the actual current deviation and temperature distribution of the CT device to achieve more reasonable temperature compensation.

[0092] By comprehensively considering various deviation rates and the local temperature difference value of the CT device to adjust the temperature compensation coefficient, temperature compensation can be more accurately carried out according to the actual operating conditions of the device. This avoids the problem of inaccurate compensation caused by only considering a single factor, improves the accuracy of temperature compensation, and makes the temperature control of the CT device more precise. Precise temperature compensation helps to maintain the temperature of each part of the CT device within a suitable range, reducing the impact of too high or too low temperature and uneven temperature distribution on the performance and lifespan of the device. Thereby enhancing the stability of the CT device operation, reducing the probability of device failure due to temperature problems, and improving the reliability and availability of the device. This technical solution can flexibly adjust the temperature compensation coefficient according to different current deviation situations and the internal temperature distribution of the device, and has good adaptability to various complex operating conditions. Whether in the case of large short-circuit current impact, obvious steady-state current deviation, or large internal temperature difference of the device, reasonable temperature compensation can be achieved through corresponding calculations and adjustments to ensure the stable operation of the device under different conditions. Reasonable temperature compensation can keep the performance of the CT device in a good state, reducing the performance fluctuation of the device caused by temperature factors. For example, for some temperature-sensitive electronic components, accurate temperature control can ensure the stability and consistency of their performance, thereby improving the imaging quality and working efficiency of the entire CT system and optimizing the overall performance of the system. By effectively controlling the temperature of the CT device, the wear and aging caused by the device being in a high-temperature or severely temperature-changing environment for a long time are reduced, the service life of the device is extended, the replacement frequency and maintenance cost of the device are reduced, and it has good economic and social benefits.

[0093] On the other hand, the formula comprehensively considers multiple factors such as the steady-state deviation rate, impact deviation rate, short-time thermal stability current deviation rate marked on the nameplate of your current CT device, average temperature rise gradient, and local temperature difference value. Through the interaction of these factors, the current and temperature states in the actual operation of the CT device can be more comprehensively reflected, making the adjustment basis of the temperature compensation coefficient more sufficient and more in line with the actual temperature compensation requirements of the device, thereby improving the accuracy of the temperature compensation coefficient adjustment. For example, different current deviation situations and temperature distribution conditions can be reflected and processed through the various factors in the formula, avoiding the one-sidedness of single-factor adjustment.

[0094] The non-linear adjustment mechanism introduced by the Sigmoid function can more precisely adjust the temperature compensation coefficient according to the actual relationship between the average temperature rise gradient of the device and the local temperature difference. For different temperature distribution characteristics, non-linear adjustment can give an adjustment range that better conforms to the actual physical process, rather than a simple linear adjustment, further improving the matching degree between the temperature compensation coefficient and the actual temperature compensation requirement and enhancing the accuracy of the adjustment. By calculating and comparing the differences between the steady-state deviation rate, the impact deviation rate and the short-time thermal stability current deviation rate marked on the nameplate of your current CT device, the change of the current deviation can be quickly captured. Once the current deviation changes, the relevant parameters in the formula will immediately change, which will quickly affect the calculation result of the temperature compensation coefficient, enabling the temperature compensation coefficient to respond promptly to the change of the current deviation and ensuring the timeliness of temperature compensation. The Sigmoid function is relatively sensitive to the average temperature rise gradient and the local temperature difference value. Once the device temperature distribution changes slightly, -T avg / ΔT will change, and the output value of the Sigmoid function will also change accordingly, thus quickly reflecting on the adjustment of the temperature compensation coefficient. This enables the temperature compensation coefficient to be adjusted in a timely manner according to the real-time change of the device temperature distribution, improving the sensitivity of temperature compensation.

[0095] Calibration analysis module, including:

[0096] Setting unit, used to set the test parameters of the CT device. The test parameters include: line number, phase, PT number, winding number, rated secondary voltage, level, current temperature, rated frequency, maximum test voltage and maximum test current parameters;

[0097] Testing unit, used to simulate the actual working conditions of the CT device and the mechanical vibration during operation, test the current of the CT device, and collect test data;

[0098] By simulating factors such as short-circuit current and temperature change in the actual working conditions, which directly affect the thermal stability of CT equipment, it is possible to verify whether the CT equipment meets the thermal stability verification formula. Simulating the actual load fluctuation in the actual working conditions can evaluate the thermal accumulation effect of the CT equipment winding. If there are frequent overloads or sudden temperature changes in the actual working conditions, it is necessary to correct the secondary load capacity calculation model by combining parameters such as copper resistivity and wire cross-sectional area to ensure the applicability of the thermal stability multiple. Mechanical vibration may cause loosening of the internal structure or insulation damage of the CT equipment. By simulating the vibration environment, the reliability of the dynamic stability verification formula can be verified, and it can be detected whether the dynamic stability multiple decreases due to mechanical stress. Long-term vibration may cause changes in the contact resistance of the secondary circuit or deformation of the winding, affecting the impedance characteristics of the CT equipment. It is necessary to compare the offset of the dynamic parameters through vibration tests to ensure that it still meets the accuracy and protection action requirements under vibration conditions. The superimposed effect of the actual working conditions and mechanical vibration may shorten the thermal stability time of the CT equipment. Combining vibration monitoring and thermal stability data can analyze the impact of vibration on the performance of the current transformer, including measurement error and stability. According to the analysis results, adjust the vibration parameters or take other measures to optimize the performance of the current transformer to ensure that the current transformer can work stably and accurately under various working conditions.

[0099] An analysis unit for deriving test data and analyzing the thermal stability verification and dynamic parameters of CT equipment using the test data.

[0100] A test unit including:

[0101] Simulating the actual working conditions of CT equipment and mechanical vibration during operation using test parameters;

[0102] Testing the current of the CT equipment using the simulated actual working conditions of the CT equipment and mechanical vibration during operation

[0103] Connecting the test wire to the CT equipment and testing the current of the CT equipment using the test parameters;

[0104] Collecting the equipment response test data under the dynamic parameters of the CT equipment, recording the mechanical stability test indicators of the CT equipment under vibration conditions and transmitting the test results to the analysis unit;

[0105] The analysis unit specifically includes:

[0106] Measuring the core parameters of the thermal stability verification of the CT equipment in real time, comparing the core parameters of the thermal stability verification measured in real time with the test data, and analyzing the secondary winding resistance and heat capacity;

[0107] Associating the impact value of the short-circuit current with the test data and obtaining the dynamic stability multiple of the CT equipment using the ratio of the impact value of the short-circuit current to the rated current;

[0108] Verify the dynamic stability multiple and impact current of the CT device and analyze the dynamic response characteristics;

[0109] Conduct a correlation analysis of the test data and standard parameters, compare the error curve with the standard limit value, and combine the short-circuit current duration and the time constant of the CT device to evaluate whether the thermal accumulation of the CT device under short-term overload is controllable. If the time constant is too small, it may lead to short-term overheating.

[0110] If it is found through comparison that the thermal stability or dynamic parameters do not meet the standards, dynamically adjust the calibration frequency according to the change trend of the test data to improve the operation and maintenance efficiency.

[0111] Compare the core parameters of the thermal stability calibration measured in real time with the test data, and analyze the secondary winding resistance and heat capacity, specifically including:

[0112] Compare the measured short-circuit current effective value and duration of the CT device with the current effective value and duration marked on the CT device nameplate to verify whether it meets the thermal stability threshold;

[0113] After correcting the secondary winding resistance of the CT device in combination with the ambient temperature, calculate whether the heat capacity loss of the CT device is consistent with the theoretical value; if the measured loss is higher than the nominal value, it may indicate winding aging or design defects.

[0114] By verifying the dynamic stability multiple, its thermal tolerance under short-circuit faults can be calibrated, ensuring that the CT device will not be damaged by overheating or deformed mechanically due to overheating during short circuits. At the same time, during the short-circuit process, additional Joule heat will be generated in the resistance of the secondary winding. Through thermal stability calibration, it can be ensured that the overall temperature rise does not exceed the allowable value.

[0115] Verify the dynamic stability multiple and impact current and analyze the dynamic response characteristics, specifically including:

[0116] Compare the measured peak value of the short-circuit impact current of the CT device with the peak value of the short-circuit impact current marked on the CT device nameplate to determine whether the CT device can withstand instantaneous mechanical stress, and obtain the verification result of the dynamic stability multiple and impact current verification;

[0117] Obtain the frequency response characteristics of the CT device, compare the dynamic errors under different current amplitudes, and analyze the dynamic response characteristics to avoid excessive resistance leading to unstable operation of the CT device, affecting the measurement accuracy and total impedance, and further affecting the heat capacity distribution.

[0118] Through thermal stability verification, the performance of the CT under high-temperature environments can be evaluated to ensure its normal operation under extreme conditions and avoid equipment damage or failures caused by overheating. Dynamic parameter comparison and analysis can help detect parameter changes of the CT under different operating conditions and promptly identify potential safety hazards. Thermal stability verification can ensure the measurement accuracy and stability of the CT at various temperatures and avoid measurement errors caused by temperature changes. Dynamic parameter comparison and analysis can verify the parameter consistency of the CT under different operating conditions and ensure the accuracy and reliability of the measurement results. By regularly performing thermal stability verification and dynamic parameter comparison and analysis, problems such as equipment aging and performance degradation can be promptly discovered, thus formulating reasonable maintenance and servicing plans to extend the service life of the equipment.

[0119] Working principle: When using the CT thermal stability verification and dynamic parameter comparison and analysis system of the present invention, according to Figure 1 and Figure 2 , it includes the following steps:

[0120] S1: Obtain the short-time thermal stability current marked on the CT equipment nameplate and the key parameters of the CT equipment operation;

[0121] S2: Measure and analyze the current waveform after the CT equipment is short-circuited, calculate the steady-state value of the short-circuit current using the current waveform, determine the maximum instantaneous peak value, calculate the impulse value of the short-circuit current using the maximum instantaneous peak value, and calculate the calorific value using the Joule's law formula;

[0122] S3: Compare the calculated short-circuit current with the short-time thermal stability current marked on the CT equipment nameplate to obtain the deviation rate, compare the deviation rate with the allowable range. If it exceeds the allowable range (such as ±5%), adjust the temperature compensation mechanism and calibrate the mechanical deformation caused by thermal expansion according to the deviation rate. The adjusted CT parameters can accurately reflect the actual short-circuit current level to ensure the thermal stability and dynamic stability of equipment such as circuit breakers and fuses match the system requirements. If the measured current is long-term lower than the nominal thermal stability value, the equipment redundancy configuration can be appropriately reduced to reduce unnecessary material costs; otherwise, higher-specification equipment needs to be replaced to avoid accelerated aging due to overload operation;

[0123] S4: Simulate the actual working conditions of the CT equipment and the mechanical vibration during operation, and test the current quantity of the CT equipment according to the simulation results;

[0124] S5: Analyze the thermal stability verification and dynamic parameters using the test data, analyze the secondary winding resistance and heat capacity, verify the dynamic stability multiple and impulse current, and analyze the dynamic response characteristics. Compare the error curve with the standard limit value, and combine the short-circuit current duration and the time constant of the CT equipment to evaluate whether the thermal accumulation of the CT equipment under short-term overload is controllable.

[0125] In summary, the CT thermal stability verification and dynamic parameter comparison and analysis system of the present invention can evaluate the performance of CT in a high-temperature environment through thermal stability verification, ensure its normal operation under extreme conditions, and avoid equipment damage or failures caused by overheating. The dynamic parameter comparison and analysis can help detect parameter changes of CT under different working conditions and timely discover potential safety hazards. Thermal stability verification can ensure the measurement accuracy and stability of CT at various temperatures and avoid measurement errors caused by temperature changes. The dynamic parameter comparison and analysis can verify the parameter consistency of CT under different working conditions and ensure the accuracy and reliability of measurement results. By regularly performing thermal stability verification and dynamic parameter comparison and analysis, problems such as equipment aging and performance degradation can be discovered in a timely manner, so as to formulate reasonable maintenance and servicing plans and extend the service life of the equipment. Analyze the thermal stability verification and dynamic parameters using test data, optimize the CT equipment selection, layout method, and protection configuration through comparing the analysis results, and improve the economy and safety of the system. By quantitatively evaluating thermal stability and dynamic stability, ensure the safe operation of the equipment under short-circuit faults and provide data support for system design, protection configuration, and operation and maintenance decisions.

[0126] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent to such process, method, article or device.

[0127] Although the embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention.

Claims

1. CT thermal stability verification and dynamic parameter comparison analysis system, characterized in that Including: A data acquisition module, which is used to acquire the short-time thermal stability current, thermal stability multiple marked on the CT device nameplate, and the key parameters of the CT device operation. The key parameters include: rated current, rated voltage, and temperature rise parameter; A calculation module, which is used to calculate the steady-state value and impulse value of the short-circuit current and calculate the heat generation using the Joule's law formula; A comparison module, which is used to compare the calculated short-circuit current with the short-time thermal stability current marked on the CT device nameplate; A calibration analysis module, which is used to simulate the actual working conditions of the CT device and the mechanical vibration during operation, test the current of the CT device according to the simulation results, and analyze the thermal stability calibration and dynamic parameters using the test data.

2. The CT thermal stability verification and dynamic parameter comparison and analysis system according to claim 1, wherein: The calculation module includes: A steady-state value calculation unit, which is used to measure and analyze the current waveform after the CT device is short-circuited, and calculate the steady-state value of the short-circuit current using the current waveform; An impulse value calculation unit, which is used to measure the current waveform when the CT device is short-circuited, determine the maximum instantaneous peak value, and calculate the impulse value of the short-circuit current using the maximum instantaneous peak value; A heat calculation unit, which is used to obtain the values of the current I, resistance R, and time t of the CT device, and calculate the heat generation of the CT device using the Joule's law formula.

3. The CT thermal stability verification and dynamic parameter comparison and analysis system according to claim 1, characterized in that: The comparison module includes: Compare the calculated short-circuit current with the short-time thermal stability current marked on the CT device nameplate to obtain a deviation rate; Set the allowable range of the deviation rate, compare the deviation rate with the allowable range. If it exceeds the allowable range, adjust the temperature compensation mechanism, and calibrate the mechanical deformation caused by thermal expansion according to the deviation rate.

4. The CT thermal stability verification and dynamic parameter comparison and analysis system according to claim 3, characterized in that: The adjustment of the temperature compensation mechanism includes: When the deviation rate corresponding to the short-time thermal stability current marked on the CT device nameplate exceeds the allowable range, determine the exceeding ratio of the deviation rate exceeding the allowable range; Compare the exceeding ratio of the deviation rate exceeding the allowable range with a preset ratio reference value; When the exceeding ratio of the deviation rate exceeding the allowable range exceeds the preset ratio reference value, retrieve the preset steady-state value reference value and impulse value reference value; Obtain the steady-state deviation rate of the steady-state value of the short-circuit current compared with the steady-state value reference value using the difference between the steady-state value of the short-circuit current and the steady-state value reference value; Obtain the impulse deviation rate of the impulse value of the short-circuit current compared with the impulse value reference value using the difference between the impulse value of the short-circuit current and the impulse value reference value; Adjust the temperature compensation mechanism using the steady-state deviation rate and impulse deviation rate of the short-circuit current combined with the deviation rate corresponding to the short-time thermal stability current marked on the current CT device nameplate.

5. The CT thermal stability verification and dynamic parameter comparison and analysis system according to claim 4, wherein: Adjust the temperature compensation mechanism using the steady-state deviation rate and impulse deviation rate of the short-circuit current combined with the deviation rate corresponding to the short-time thermal stability current marked on the current CT device nameplate, including: Compare the impulse deviation rate of the short-circuit current with the deviation rate corresponding to the short-time thermal stability current marked on the current CT device nameplate to obtain a first comparison result; Compare the steady-state deviation rate of the short-circuit current with the deviation rate corresponding to the short-time thermal stability current marked on the current CT device nameplate to obtain a second comparison result; When the first comparison result indicates that the impact deviation rate of the short-circuit current exceeds the deviation rate corresponding to the short-time thermal stability current marked on the nameplate of your current CT device, or when the second comparison result indicates that the steady-state deviation rate of the short-circuit current exceeds the deviation rate corresponding to the short-time thermal stability current marked on the nameplate of your current CT device, then the preset initial temperature compensation coefficient is retrieved; Retrieve the current maximum local temperature and minimum local temperature of the CT device; Perform a difference process using the maximum local temperature and the minimum local temperature to obtain the current local temperature difference value of the CT device; Adjust the initial temperature compensation coefficient by using the local temperature difference value in combination with the impact deviation rate, steady-state deviation rate, and the deviation rate corresponding to the short-time thermal stability current marked on the nameplate of your current CT device to obtain the adjusted temperature compensation coefficient.

6. The CT thermal stability verification and dynamic parameter comparison and analysis system according to claim 1, characterized in that: The verification and analysis module includes: A setting unit for setting the test parameters of the CT device, and the test parameters include: line number, phase, PT number, winding number, rated secondary voltage, level, current temperature, rated frequency, maximum test voltage, and maximum test current parameters; A test unit for simulating the actual working conditions of the CT device and the mechanical vibration during operation, and testing the current of the CT device to collect test data; An analysis unit for exporting the test data and analyzing the thermal stability verification and dynamic parameters of the CT device by using the test data.

7. The CT thermal stability verification and dynamic parameter comparison and analysis system according to claim 6, characterized in that: The test unit includes: Simulate the actual working conditions of the CT device and the mechanical vibration during operation by using the test parameters; Test the current of the CT device by using the simulated actual working conditions of the CT device and the mechanical vibration during operation; Connect the test wire to the CT device and test the current of the CT device by using the test parameters; Collect the device response test data under the dynamic parameters of the CT device, record the mechanical stability test indicators of the CT device under vibration conditions, and transmit the test results to the analysis unit.

8. The CT thermal stability verification and dynamic parameter comparison and analysis system according to claim 6, wherein: The analysis unit specifically includes: Measure the core parameters of the thermal stability verification of the CT device in real time, compare the core parameters of the thermal stability verification measured in real time with the test data, and analyze the secondary winding resistance and heat capacity; Associate the impact value of the short-circuit current with the test data, and obtain the dynamic stability multiple of the CT device by using the ratio of the impact value of the short-circuit current to the rated current; Verify the dynamic stability multiple and impact current of the CT device and analyze the dynamic response characteristics; Perform a correlation analysis on the test data and standard parameters, compare the error curve with the standard limit value, and evaluate whether the thermal accumulation of the CT device under short-time overload is controllable in combination with the short-circuit current duration and the time constant of the CT device; If it is found through comparison that the thermal stability or dynamic parameters do not meet the standards, dynamically adjust the verification frequency according to the change trend of the test data.

9. The CT thermal stability verification and dynamic parameter comparison and analysis system according to claim 8, wherein: The comparison of the core parameters of the thermal stability verification measured in real time with the test data and the analysis of the secondary winding resistance and heat capacity specifically include: Compare the measured effective value and duration of the short-circuit current of the CT device with the effective value and duration of the current marked on the nameplate of the CT device to verify whether it meets the thermal stability threshold; After correcting the resistance of the secondary winding of the CT device in combination with the ambient temperature, calculate whether the heat capacity loss of the CT device is consistent with the theoretical value.

10. The CT thermal stability verification and dynamic parameter comparison and analysis system according to claim 8, characterized in that: The verification of the dynamic stability multiple and the impulse current and the analysis of the dynamic response characteristics specifically include: Compare the measured peak short-circuit impulse current of the CT device with the peak short-circuit impulse current marked on the nameplate of the CT device to determine whether the CT device can withstand instantaneous mechanical stress, and obtain the verification result of the verification of the dynamic stability multiple and the impulse current; Obtain the frequency response characteristics of the CT device, compare the dynamic errors under different current amplitudes, and analyze the dynamic response characteristics.

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