Non-power-outage calibration method and device for medium and low voltage current transformer and medium

Abstract

The invention discloses an uninterrupted calibration method and device for a medium and low voltage current transformer and a medium. The method comprises the following steps: measuring a primary side original current signal of a to-be-measured current transformer by using a pre-prepared mobile calibration platform; injecting a reverse current with the same frequency as the injection current source of the current transformer to be detected into the current transformer to be detected, and counteracting a primary side original current signal of the current transformer to be detected; generating a pilot frequency current according to a pre-selected pilot frequency signal by using an injection current source, inputting the pilot frequency current to a primary side of the current transformer to be detected for pilot frequency current calibration, and collecting a secondary side output signal; performing error analysis on the to-be-detected current transformer based on the secondary side output signal, and determining an error analysis result; and adjusting the calibration parameters of the to-be-detected current transformer based on the error analysis result to perform pilot frequency current calibration again until the error analysis result meets a preset requirement, and completing calibration of the to-be-detected current transformer.

Description

Technical Field

[0001] The present invention relates to the technical field of power system detection and calibration, and more particularly to a method, device and medium for non-stop calibration of medium and low voltage current transformers. Background Art

[0002] Current transformers, as crucial equipment in power systems, are widely used in current measurement, metering, and protection. Their accuracy directly impacts the measurement and protection performance of power systems. To ensure proper operation and accurate measurement, regular calibration is essential. However, traditional current transformer calibration methods often require power outages, which not only disrupts the normal operation of the power system but also increases the complexity and cost of maintenance and repairs.

[0003] Traditional calibration methods typically require disconnecting the power supply, shutting down the equipment to be calibrated, performing the calibration, and then restoring power. This is especially true for large power facilities like substations and distribution networks, where power outages can cause significant disruptions, impacting production and power supply. As electricity demand continues to increase, the requirements for power facility operation and maintenance are becoming increasingly stringent. Therefore, developing a method that can perform current transformer calibration without power outages is of great technical significance and application value. Summary of the Invention

[0004] In view of the deficiencies in the prior art, the present invention provides a method, device and medium for non-power-off calibration of medium and low voltage current transformers.

[0005] According to one aspect of the present invention, a method for calibrating a medium- and low-voltage current transformer without power outage is provided, comprising:

[0006] Measure the primary side original current signal of the current transformer to be tested using a pre-prepared mobile calibration platform;

[0007] Injecting a reverse current of the same frequency as the injection current source of the current transformer to be tested into the current transformer to be tested, thereby offsetting the original current signal on the primary side of the current transformer to be tested;

[0008] Using an injection current source to generate a frequency-independent current according to a pre-selected frequency-independent signal, the frequency-independent current is input to the primary side of the current transformer to be tested for frequency-independent current calibration, and the secondary side output signal is collected;

[0009] Perform error analysis on the current transformer to be measured based on the secondary side output signal and determine the error analysis result;

[0010] Based on the error analysis results, the calibration parameters of the current transformer to be tested are adjusted to re-perform the heterodyne current calibration until the error analysis results meet the preset requirements, thus completing the calibration of the current transformer to be tested.

[0011] Optionally, the original current signal includes: current amplitude, current frequency, and current phase, and measuring the primary side original current signal of the current transformer to be tested using a pre-prepared mobile calibration platform includes:

[0012] A standard current transformer is used to measure the current amplitude of the primary side current of the current transformer to be tested;

[0013] Calculating and analyzing the current frequency of the primary side current using a frequency analyzer; and

[0014] The phase measurement equipment is used to calculate, analyze and record the current phase of the primary side current.

[0015] Optionally, injecting a reverse current of the same frequency as the injection current source of the current transformer to be tested into the current transformer to be tested, so as to offset the original current signal of the primary side of the current transformer to be tested, comprises:

[0016] A reverse current with the same frequency but opposite phase as the original current signal is generated by injecting a current source, wherein the amplitude and phase of the reverse current are precisely controlled by adjusting the injection current source;

[0017] The generated reverse current is injected into the primary side of the current transformer to be tested, and the amplitude and phase of the reverse current are feedback-adjusted and superimposed on the original current signal to eliminate the original current signal on the primary side of the current transformer to be tested.

[0018] Optionally, the generated reverse current is injected into the primary side of the current transformer to be measured, and the amplitude and phase of the reverse current are feedback-adjusted to be superimposed on the original current signal to eliminate the original current signal on the primary side of the current transformer to be measured, including:

[0019] Injecting the generated reverse current into the primary side of the current transformer to be tested, and monitoring the output current signal of the secondary side of the current transformer to be tested;

[0020] Perform error analysis based on the output current signal to determine the offset error;

[0021] Based on the cancellation error, the amplitude and phase of the reverse current are adjusted and re-injected into the primary side of the current transformer to be measured until the cancellation error meets the preset requirements to cancel the original current signal on the primary side of the current transformer to be measured.

[0022] Optionally, the method further includes storing calibration data of the current transformer to be tested and generating a calibration report of the current transformer to be tested, wherein the calibration report includes error analysis before and after calibration, a calibration curve of the current transformer to be tested, corrected measurement parameters, and data during the calibration process.

[0023] Optionally, performing error analysis on the current transformer to be measured based on the secondary-side output signal to determine the error analysis result includes:

[0024] Calculate the frequency response and phase difference of the current transformer under test;

[0025] Calculating the proportional error of the current transformer under test based on the frequency response, the secondary side output signal, and the original current signal of the current transformer under test;

[0026] The comprehensive error of the current transformer to be measured is determined based on the phase difference and the proportional error.

[0027] According to another aspect of the present invention, a non-stop calibration device for medium and low voltage current transformers is provided, comprising:

[0028] A measurement module is used to measure the primary side original current signal of the current transformer to be tested using a pre-prepared mobile calibration platform;

[0029] The cancellation module is used to inject a reverse current of the same frequency as the injection current source of the current transformer under test into the current transformer under test, thereby canceling the original current signal of the primary side of the current transformer under test;

[0030] An input module is used to generate a heterofrequency current using an injection current source according to a preselected heterofrequency signal, input the heterofrequency current to the primary side of the current transformer to be tested for heterofrequency current calibration, and collect the secondary side output signal;

[0031] An analysis module is used to perform error analysis on the current transformer to be measured based on the secondary side output signal and determine the error analysis result;

[0032] The calibration module is used to adjust the calibration parameters of the current transformer to be tested based on the error analysis results and re-calibrate the different-frequency current until the error analysis results meet the preset requirements, thereby completing the calibration of the current transformer to be tested.

[0033] According to another aspect of the present invention, a computer-readable storage medium is provided, wherein the storage medium stores a computer program, and the computer program is used to execute the method described in any one of the above aspects of the present invention.

[0034] According to another aspect of the present invention, an electronic device is provided, comprising: a processor; a memory for storing processor-executable instructions; and a processor for reading executable instructions from the memory and executing the instructions to implement the method described in any one of the above aspects of the present invention.

[0035] Thus, the present invention combines the same-frequency reverse current injection method with the different-frequency current calibration method to effectively and precisely calibrate current transformers, particularly in terms of frequency response and nonlinear characteristics. By selecting appropriate low-frequency (e.g., 35Hz) and high-frequency (e.g., 100-200Hz) signals, the transformer's performance at different frequencies can be deeply analyzed, and errors at 50Hz can be calculated and corrected. The integration of intelligent control and data analysis methods ensures the automation, accuracy, and efficiency of the entire calibration process, thereby significantly improving the calibration accuracy and reliability of current transformers. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] A more complete understanding of exemplary embodiments of the present invention may be obtained by referring to the following drawings:

[0037] Figure 1 This is a flow chart of a method for non-power-off calibration of a medium and low voltage current transformer provided by an exemplary embodiment of the present invention;

[0038] Figure 2 1 is a schematic diagram of an implementation architecture of a method for non-power-off calibration of a medium and low voltage current transformer provided by an exemplary embodiment of the present invention;

[0039] Figure 3 This is a flow chart of a primary-side same-frequency reverse current injection current provided by an exemplary embodiment of the present invention;

[0040] Figure 4 This is a flow chart of calibrating a transformer's different-frequency current according to an exemplary embodiment of the present invention;

[0041] Figure 5 2 is a schematic structural diagram of a medium and low voltage current transformer non-stop calibration device provided by an exemplary embodiment of the present invention;

[0042] Figure 6 This is a structure of an electronic device provided by an exemplary embodiment of the present invention. DETAILED DESCRIPTION

[0043] Below, the exemplary embodiments according to the present invention will be described in detail with reference to the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments of the present invention, and it should be understood that the present invention is not limited to the exemplary embodiments described herein.

[0044] It should be noted that the relative arrangement of components and steps, the numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present invention unless specifically stated otherwise.

[0045] Those skilled in the art will understand that the terms "first" and "second" in the embodiments of the present invention are only used to distinguish different steps, devices or modules, and neither represent any specific technical meaning nor indicate the necessary logical order between them.

[0046] It should also be understood that, in the embodiments of the present invention, “a plurality of” may refer to two or more than two, and “at least one” may refer to one, two or more than two.

[0047] It should also be understood that any component, data or structure mentioned in the embodiments of the present invention can generally be understood as one or more, unless explicitly limited or otherwise indicated in the context.

[0048] In addition, the term "and / or" in this invention merely describes an association relationship between related objects, indicating that three possible relationships exist. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. Furthermore, the character " / " in this invention generally indicates that the related objects are in an "or" relationship.

[0049] It should also be understood that the description of the various embodiments of the present invention focuses on the differences between the various embodiments, and the same or similar aspects thereof can be referenced with each other. For the sake of brevity, they will not be described one by one.

[0050] At the same time, it should be understood that for the convenience of description, the sizes of the various parts shown in the drawings are not drawn according to the actual proportional relationship.

[0051] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses.

[0052] Technologies, methods, and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be considered part of the specification.

[0053] It should be noted that like reference numerals and letters refer to like items in the following figures, and therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0054] Embodiments of the present invention can be applied to electronic devices such as terminal devices, computer systems, and servers, and can operate in conjunction with numerous other general-purpose or specialized computing system environments or configurations. Examples of well-known terminal devices, computing systems, environments, and / or configurations suitable for use with terminal devices, computer systems, servers, and other electronic devices include, but are not limited to, personal computer systems, server computer systems, thin clients, thick clients, handheld or laptop devices, microprocessor-based systems, set-top boxes, programmable consumer electronics, network personal computers, minicomputer systems, mainframe computer systems, and distributed cloud computing technology environments including any of the above.

[0055] Electronic devices such as terminal devices, computer systems, and servers can be described in the general context of computer system-executable instructions (such as program modules) executed by a computer system. Generally, program modules can include routines, programs, object programs, components, logic, data structures, etc., which perform specific tasks or implement specific abstract data types. Computer systems / servers can be implemented in a distributed cloud computing environment, where tasks are performed by remote processing devices linked via a communication network. In a distributed cloud computing environment, program modules can be located on local or remote computing system storage media, including storage devices.

[0056] Exemplary Methods

[0057] Figure 1 This is a flow chart of a method for calibrating a medium and low voltage current transformer without power outages provided by an exemplary embodiment of the present invention. This embodiment can be applied to electronic devices, such as Figure 1 As shown, the method 100 for calibrating a medium and low voltage current transformer without power outage includes the following steps:

[0058] Step 101: using a pre-prepared mobile calibration platform to measure the primary side original current signal of the current transformer to be tested;

[0059] Step 102: injecting a reverse current of the same frequency as the injection current source of the current transformer under test into the current transformer under test to offset the original current signal on the primary side of the current transformer under test;

[0060] Step 103: using an injection current source to generate an inter-frequency current according to a pre-selected inter-frequency signal, and inputting the inter-frequency current into the primary side of the current transformer to be tested to perform inter-frequency current calibration, and collecting the secondary side output signal;

[0061] Step 104, performing error analysis on the current transformer to be tested based on the secondary side output signal, and determining an error analysis result;

[0062] Step 105 : Based on the error analysis result, the calibration parameters of the current transformer to be tested are adjusted to re-perform the inter-frequency current calibration until the error analysis result meets the preset requirements, thereby completing the calibration of the current transformer to be tested.

[0063] Specifically, to address the technical problems in the background art, the present invention provides a design method for a mobile medium- and low-voltage current transformer calibration platform without power outages. This method aims to solve the problem of traditional current transformer calibration requiring power outages. Through innovative current injection technology, current transformers can be accurately calibrated without power outages. Combining the different-frequency current calibration method with the same-frequency reverse current injection calibration method, the specific technical solution is as follows:

[0064] refer to Figure 2 The specific implementation block diagram of the present invention shown is as follows:

[0065] Mobile platform structure: provides support and operating interface for the equipment, including a wheeled mobile platform and power interface.

[0066] Injection current source module: includes reverse current injection and frequency-different current injection modules, used to generate the required current signal.

[0067] Measurement and acquisition module: used to collect the secondary output signal of the current transformer.

[0068] Control and feedback system: performs real-time data acquisition, analysis, error correction and optimized calibration control.

[0069] Intelligent control and analysis system: Embedded algorithms analyze data in real time, correct errors, and generate calibration curves.

[0070] Data storage and remote transmission module: wirelessly transmit data to a remote server for storage and monitoring.

[0071] Display and operation interface: Provides an interactive interface between operators and the platform to monitor data in real time.

[0072] Calibration report generation and remote monitoring: Automatically generate calibration reports and support remote monitoring and data management.

[0073] 1. Same frequency reverse current injection calibration method, such as Figure 3 As shown:

[0074] The core idea of the same-frequency reverse current injection calibration method is to inject a current with the same frequency and opposite direction as the original current into the primary side of the current transformer. The offset effect of this reverse current eliminates the influence of the primary current on the calibration process, thus ensuring the measurement accuracy. Detailed process:

[0075] (1) Measure the original primary current:

[0076] Before calibration, measure the current on the primary side of the current transformer and record the current amplitude, frequency, and phase. This current is usually the grid current.

[0077] (2) Injection of reverse current:

[0078] A high-precision current source is used to inject a current signal with the same frequency and opposite direction as the original current into the primary side of the current transformer. To ensure signal accuracy, the waveform of the current source should exactly match that of the original current, and the amplitude and phase should be precisely adjusted.

[0079] (3) Adjust the reverse current amplitude and phase:

[0080] By controlling the current source and adjusting the amplitude and phase of the injected current, the injected reverse current is guaranteed to perfectly cancel the original current. At this point, the influence of the original current disappears completely, and only the calibration signal remains.

[0081] (4) Calibrate the secondary side signal:

[0082] Use accurate measurement equipment to acquire the output signal from the secondary side of the current transformer. At this point, the secondary output should only contain the calibration error caused by the reverse current and not be affected by the primary current.

[0083] (5) Error calculation and correction:

[0084] The collected secondary-side signal is analyzed for errors, and correction data is calculated based on the errors caused by reverse current. Finally, the correction data is used to generate a calibration curve for the current transformer and update the transformer's measurement data.

[0085] 2. Different frequency current calibration method, such as Figure 4 As shown:

[0086] Frequency selection principle: In order to test the response characteristics of the current transformer at different frequencies, it is key to select the appropriate frequency current signal. Generally, the following frequency range is selected:

[0087] Low frequency (less than 50Hz, 35Hz recommended): Low frequency signals are helpful for testing the nonlinear response of current transformers at low frequencies, especially the effects of ferromagnetic properties. At low frequencies, the magnetic permeability of current transformers is high and they are susceptible to magnetic saturation effects.

[0088] High frequency (above 50 Hz, 100-200 Hz recommended): High-frequency signals are used to test the frequency response characteristics of transformers, especially saturation, nonlinear distortion, and electromagnetic hysteresis at high frequencies. The inductance and capacitance effects of transformers are particularly important at high frequencies.

[0089] Frequency selection criteria: Selecting a low frequency (35Hz) helps verify the frequency response capability of the transformer at low frequencies, especially the response characteristics of the core material.

[0090] High frequency (100-200Hz) can test the frequency response of the current transformer at high frequency, especially the distortion caused by electromagnetic saturation and inductance effect at high frequency.

[0091] Derivation of the 50Hz error: The frequency response of a current transformer is closely related to its ferromagnetic and frequency characteristics. The 50Hz error, in particular, is primarily caused by the transformer's nonlinear characteristics and mismatched frequency response. Based on the following model, we can derive the 50Hz error.

[0092] 1. Frequency response model of transformer:

[0093] Assume that the frequency response function of the current transformer is:

[0094]

[0095] Where: A is the gain of the transformer; f c is the critical frequency of the transformer, indicating the frequency point where the response begins to attenuate; f is the frequency.

[0096] When the frequency is 50Hz, the frequency response is:

[0097]

[0098] 2. Phase difference calculation:

[0099] The phase difference caused by the frequency response of the transformer can be expressed as:

[0100]

[0101] Here, arg() represents the complex phase angle. This formula can be used to calculate the phase difference at 50 Hz.

[0102] 3. Error correction:

[0103] Based on the frequency response and phase difference, the error at 50Hz is derived. Assuming the actual current is Iactual and the output of the transformer is Ioutput, the error can be calculated using the following formula:

[0104] I output =I actual ·H(50)

[0105] The error ε(50) is:

[0106] ε(50)=I actual -I output

[0107] The comprehensive error w is the sum of ε(50) and the phase difference. The error w can be corrected to adjust the measurement data of the mutual inductor.

[0108] 4. Generate error correction curve:

[0109] By calculating the error at 50 Hz, an error correction curve can be generated. This curve provides correction values at the actual operating frequency, thereby adjusting the transformer error and ensuring accurate current measurement.

[0110] 5. Intelligent control and data analysis methods

[0111] The design of the intelligent control system ensures the automation and efficiency of the calibration process. The system provides intelligent support for calibration through real-time data collection, analysis and processing. Specific methods and processes:

[0112] 1. Data collection:

[0113] The signal acquisition module monitors the output signal of the current transformer's secondary side in real time, collecting information such as amplitude, phase, and frequency. The collected data must be sufficiently accurate, especially the current transformer's response data at different frequencies.

[0114] 2. Real-time error analysis:

[0115] During real-time data acquisition, embedded algorithms perform error analysis, comparing actual measured data with theoretical models (or standard signals). Using methods such as frequency response models and phase difference calculations, they estimate the source of the error in real time and determine whether the current transformer has nonlinear response or frequency response deviation.

[0116] 3. Error correction and optimization:

[0117] The system performs error correction based on the error analysis results, adjusting the current transformer's internal parameters (such as gain and frequency response function) to maximize error correction. After error correction, the control algorithm retests the transformer to ensure measurement accuracy at the target frequency (such as 50 Hz).

[0118] 4. Generate calibration report:

[0119] After the calibration process is complete, the intelligent control system generates a detailed calibration report that includes all test data, error analysis results, corrective actions, and the final calibration curve. The calibration report can be used to document equipment performance and provide a reference for long-term tracking and optimization.

[0120] 5. Remote monitoring and data transmission:

[0121] Calibration data is uploaded to a remote server via a wireless data transmission module, supporting remote monitoring and data storage. Through the network platform, technicians can view calibration status in real time and perform data management and analysis.

[0122] Thus, the present invention combines the same-frequency reverse current injection method with the different-frequency current calibration method to effectively and precisely calibrate current transformers, particularly in terms of frequency response and nonlinear characteristics. By selecting appropriate low-frequency (e.g., 35Hz) and high-frequency (e.g., 100-200Hz) signals, the transformer's performance at different frequencies can be deeply analyzed, and errors at 50Hz can be calculated and corrected. The integration of intelligent control and data analysis methods ensures the automation, accuracy, and efficiency of the entire calibration process, thereby significantly improving the calibration accuracy and reliability of current transformers.

[0123] In one embodiment of the present invention, using the calibration of medium and low voltage current transformers in a substation as an example, we describe in detail how to achieve precise calibration using the technical solution of the present invention. This embodiment focuses on the specific steps and operational procedures for the reverse current injection method and the inter-frequency current calibration method in practical applications.

[0124] 1. Equipment preparation and on-site installation

[0125] Before starting the calibration work, you first need to check and prepare the various equipment on the calibration platform.

[0126] Mobile platform: This wheeled platform allows for easy movement within the substation. Adjusting the platform's position via the control panel ensures calibration coverage of multiple current transformers.

[0127] Injection Current Source: Equipped with a high-precision, adjustable current source, it supports generating both inverse and reverse currents at the same and different frequencies. This current source is regulated via a computer or remote control panel to ensure high output current accuracy, meeting calibration requirements.

[0128] Measurement and feedback system: Using high-precision current sensors and data acquisition devices, the secondary-side current signal is monitored and recorded in real time. This data will be used for subsequent error analysis and calibration.

[0129] 2. Measure the original current signal

[0130] Before calibrating the current transformer, you first need to measure and record the original current signal on the primary side of the current transformer. The measurement content includes:

[0131] Current Amplitude: Use a standard current transformer to measure the current amplitude on the primary side.

[0132] Current frequency: Use a frequency analyzer to measure the frequency of the current and ensure that the frequency range of the original current is within the expected range.

[0133] Current phase: Use a phase measurement device to record the phase of the current to ensure that the signal can be correctly phase-adjusted during the calibration process.

[0134] 3. Same frequency reverse current injection

[0135] Next, reverse current injection is used to offset the effect of the original current. The steps are as follows:

[0136] Generate reverse current: A current source is used to generate a reverse current with the same frequency as the original current but opposite phase. The amplitude and phase of the reverse current need to be precisely controlled by adjusting the current source.

[0137] Reverse current injection: This generates a reverse current that is injected into the primary side of the current transformer, where it is superimposed on the original current. This reverse current eliminates the effects of the original current and provides pure calibration data for the calibration signal on the secondary side.

[0138] Feedback Regulation: During reverse current injection, the secondary-side output signal is monitored in real time, and the feedback system analyzes errors. If the secondary-side signal fails to completely offset the effect of the primary current, the system automatically adjusts the amplitude and phase of the reverse current until the error is minimized.

[0139] 4. Different frequency current calibration

[0140] After completing the reverse current injection, in order to further improve the calibration accuracy of the current transformer, perform the frequency-differential current calibration. The steps are as follows:

[0141] Selecting a frequency-varying signal: Based on the operating requirements of the current transformer, select an appropriate frequency-varying current signal. Typically, a low-frequency signal (e.g., 35 Hz) and a high-frequency signal (e.g., 100 Hz to 200 Hz) are selected to test the transformer's response at different frequencies.

[0142] Generating a current at a different frequency: A current source is used to generate a current signal at a different frequency and inject it into the primary side of the current transformer. The output frequency of the current source should match the selected frequency and be precisely adjustable within the desired frequency range.

[0143] Acquiring secondary-side signals: After injecting a current with an irregular frequency, use high-precision measurement equipment to acquire the output signal from the secondary side of the current transformer. By analyzing the output signal, the frequency response characteristics of the transformer can be evaluated.

[0144] Analyze errors: Analyze errors in the secondary-side signal due to frequency response mismatch by comparing it with a theoretical model or a standard signal.

[0145] Error correction and optimization: Based on the analysis results, adjust the current transformer calibration parameters (such as gain, frequency response function, etc.) to minimize errors and optimize calibration accuracy.

[0146] 5. Data storage and report generation

[0147] Real-time data storage: Through the control system, all calibration data (including current amplitude, frequency, phase, and correction parameters) are stored in real time in a local database or cloud platform. This data is used for subsequent analysis, tracking, and optimization.

[0148] Generate calibration report: After the calibration process is completed, the intelligent control system will automatically generate a detailed calibration report. The report includes:

[0149] 1) Error analysis before and after calibration

[0150] 2) Calibration curve of current transformer

[0151] 3) Corrected measurement parameters

[0152] 4) Important data during calibration

[0153] 5) The calibration report can be transmitted to the remote monitoring system via the network, facilitating subsequent monitoring and management by the power company or maintenance personnel.

[0154] 6. Remote monitoring and optimization

[0155] Calibration data can be uploaded to the cloud or remote servers in real time via a wireless data transmission module, enabling remote monitoring by power companies or personnel. The intelligent control system analyzes the stored data in real time, providing calibration optimization recommendations and automatically adjusting and optimizing calibration results based on real-time operating data.

[0156] 7. Complete calibration

[0157] After completing the above steps, the current transformer calibration is complete. At this point, the current transformer's performance is optimized to the maximum extent possible, and the calibration accuracy meets the required requirements. The entire process requires no power outage, ensuring continuous and stable operation of the power system.

[0158] Summary: Through the specific application of this embodiment, it can be seen that the mobile medium and low voltage current transformer non-power-off calibration platform of the present invention has strong practicality and flexibility. The combination of reverse current injection and frequency-differential current calibration can not only accurately offset the interference of the original current, but also ensure comprehensive calibration of the current transformer at multiple frequencies, greatly improving the measurement accuracy and reliability of the current transformer, while avoiding unnecessary production interruptions caused by power outages.

[0159] In summary, the present invention's mobile, non-power-off calibration platform for medium- and low-voltage current transformers offers significant technical advantages, effectively resolving key challenges in conventional technologies, particularly those related to power-off calibration, accuracy, and applicability. The following details the advantages of the present invention and highlights its uniqueness and innovations by contrasting it with the shortcomings of conventional technologies.

[0160] 1. Avoid power outage calibration (the main difference from traditional technology)

[0161] Traditional technology: In traditional current transformer calibration methods, the calibration process often requires a power outage. To accurately calibrate the current transformer, the power supply must be shut down, which means long outages and disruptions to the power system, affecting grid stability and normal operations.

[0162] Power outage calibration not only increases the operating cost of the power system, but may also lead to significant economic losses, especially in places where frequent calibration is required (such as substations, distribution networks, etc.).

[0163] This invention uses a non-stop calibration method to perform calibration while the current transformer is operating normally, without disconnecting the power supply. Through innovative current injection techniques (such as frequency-reversed current injection and frequency-differential current calibration), accurate calibration can be performed without interrupting grid operation.

[0164] This technology significantly reduces the impact of power outages on grid operations, saves operation and maintenance costs, avoids production interruptions caused by power outages, and improves grid reliability.

[0165] 2. High-precision calibration effect (difference from the calibration accuracy of traditional technology)

[0166] Traditional techniques: Traditional calibration methods typically perform error correction by directly measuring the output signal of the current transformer. However, these methods often suffer from insufficient calibration accuracy, especially when the current waveforms do not match during measurement, which can affect the accuracy of the measurement results. Traditional calibration relies on manual adjustment and testing, which is prone to human error. The calibration process can also be significantly affected by external factors (such as current fluctuations and equipment aging).

[0167] This invention utilizes a high-precision current source and intelligent algorithm for calibration through both the same-frequency reverse current injection method and the different-frequency current calibration method. This method can accurately measure the error of current transformers at different frequencies, eliminating the error sources associated with traditional methods. The same-frequency reverse current injection method eliminates interference from the primary current on calibration by injecting a current of the same frequency opposite to the primary current, improving the accuracy of the calibration process.

[0168] The different-frequency current calibration method can accurately analyze the frequency response of the transformer by injecting different-frequency current signals without affecting the original current measurement function, thereby further improving the calibration accuracy.

[0169] 3. Wide applicability (adaptability difference from traditional technologies)

[0170] Traditional techniques: Traditional calibration methods often rely on specialized laboratory equipment or are only applicable to specific current transformer specifications and types. For example, some methods may only calibrate low-voltage current transformers or require specialized operating conditions to ensure calibration accuracy. These methods are limited in scope and may require significant downtime, making them inflexible for the diverse range of current transformer types in the field.

[0171] This mobile platform is highly adaptable and suitable for a wide range of low- and medium-voltage current transformers, from those in low-voltage substations to equipment in industrial power distribution systems. Its portable design allows for easy portability and deployment, supports field use, and allows for flexible configuration based on the needs of diverse scenarios. Therefore, it is widely applicable to calibration needs across various power systems and power equipment manufacturing sectors.

[0172] 4. Intelligent control and automated analysis (difference from traditional manual calibration)

[0173] Traditional Technology: Traditional calibration processes often rely on manual measurement and adjustment, making the process cumbersome and time-consuming. Analysis and correction of calibration results are also often manual, susceptible to operator experience and skill level. Furthermore, traditional calibration methods lack real-time data monitoring and remote control capabilities, resulting in inadequate data tracking and archiving during the calibration process.

[0174] The present invention introduces an intelligent control system, which uses an embedded algorithm to perform real-time analysis and error correction on the collected data. The entire calibration process is automated, reducing human intervention and improving calibration efficiency and accuracy.

[0175] The intelligent control system supports real-time data visualization, displaying calibration data and error correction status in real time, allowing operators to monitor calibration progress and improve work efficiency. The system also features a wireless data transmission module that supports remote monitoring and storage of calibration data, facilitating subsequent calibration tracking and optimization. Automatically generated calibration reports allow operators to more accurately analyze calibration results, reducing operational complexity and error rates.

[0176] 5. Portability and flexibility (difference from traditional fixed equipment)

[0177] Traditional technology: Traditional calibration equipment is typically bulky and fixed in design, requiring on-site operation by professionals and requiring complex equipment installation and commissioning. This limits the equipment’s transportation and use, making it particularly inflexible in field applications.

[0178] This invention utilizes a mobile platform design, resulting in excellent portability and flexibility. This allows for rapid deployment and commissioning based on actual needs, adapting to a variety of field testing conditions. In particular, in scenarios such as substations and distribution networks, the mobile calibration platform can be quickly deployed for rapid and efficient calibration, significantly improving the convenience and efficiency of field work.

[0179] Therefore, this invention significantly improves the calibration efficiency, accuracy, and adaptability of current transformers through its innovative, non-power-off calibration method, high-precision current source, and intelligent control system. Compared with traditional methods, this invention offers significant advantages in practical applications due to its avoidance of power outages, improved accuracy, increased applicability, and intelligent control. It not only overcomes the limitations of traditional calibration methods but also better meets the high calibration accuracy and efficiency requirements of modern power systems.

[0180] Exemplary devices

[0181] Figure 5 FIG. 1 is a schematic diagram of a non-stop calibration device for medium and low voltage current transformers provided by an exemplary embodiment of the present invention. Figure 5 As shown, the apparatus 500 includes:

[0182] The measurement module 510 is configured to measure the primary side original current signal of the current transformer to be tested using a pre-prepared mobile calibration platform;

[0183] The cancellation module 520 is used to inject a reverse current of the same frequency as the injection current source of the current transformer under test into the current transformer under test, thereby canceling the original current signal of the primary side of the current transformer under test;

[0184] An input module 530 is configured to generate an inter-frequency current using an injection current source according to a pre-selected inter-frequency signal, input the inter-frequency current to the primary side of the current transformer to be tested for inter-frequency current calibration, and collect a secondary side output signal;

[0185] An analysis module 540 is configured to perform error analysis on the current transformer to be measured based on the secondary side output signal and determine an error analysis result;

[0186] The calibration module 550 is configured to adjust the calibration parameters of the current transformer to be tested based on the error analysis result and re-perform the inter-frequency current calibration until the error analysis result meets the preset requirements, thereby completing the calibration of the current transformer to be tested.

[0187] Optionally, the original current signal includes: current amplitude, current frequency and current phase, and the measurement module 510 includes:

[0188] A measurement submodule, configured to measure the current amplitude of the primary side current of the current transformer to be measured using a standard current transformer;

[0189] A first analysis submodule is configured to calculate and analyze the current frequency of the primary side current using a frequency analyzer; and

[0190] The second analysis submodule is used to calculate, analyze and record the current phase of the primary side current using a phase measurement device.

[0191] Optionally, the offset module 520 includes:

[0192] a generation submodule, configured to generate a reverse current having the same frequency as the original current signal but opposite phase through an injection current source, wherein the amplitude and phase of the reverse current are precisely controlled by adjusting the injection current source;

[0193] The injection submodule is used to inject the generated reverse current into the primary side of the current transformer to be tested, and feedback-adjust the amplitude and phase of the reverse current to superimpose with the original current signal to eliminate the original current signal on the primary side of the current transformer to be tested.

[0194] Optionally, inject submodules, including:

[0195] Injecting the generated reverse current into the primary side of the current transformer to be tested, and monitoring the output current signal of the secondary side of the current transformer to be tested;

[0196] Perform error analysis based on the output current signal to determine the offset error;

[0197] Based on the cancellation error, the amplitude and phase of the reverse current are adjusted and re-injected into the primary side of the current transformer to be measured until the cancellation error meets the preset requirements to cancel the original current signal on the primary side of the current transformer to be measured.

[0198] Optionally, the device 500 further includes: a generation module for storing the calibration data of the current transformer to be tested and generating a calibration report of the current transformer to be tested, wherein the calibration report includes: error analysis before and after calibration, a calibration curve of the current transformer to be tested, corrected measurement parameters, and data during the calibration process.

[0199] Optionally, the analysis module 540 includes:

[0200] A first calculation submodule is used to calculate the frequency response and phase difference of the current transformer to be tested;

[0201] A second calculation submodule is used to calculate the proportional error of the current transformer to be measured based on the frequency response, the secondary side output signal and the original current signal of the current transformer to be measured;

[0202] The determination submodule is used to determine the comprehensive error of the current transformer to be measured based on the phase difference and the proportional error.

[0203] Exemplary electronic devices

[0204] Figure 6 This is the structure of an electronic device provided by an exemplary embodiment of the present invention. Figure 6 As shown, the electronic device 60 includes one or more processors 61 and a memory 62 .

[0205] The processor 61 may be a central processing unit (CPU) or other forms of processing units having data processing capabilities and / or instruction execution capabilities, and may control other components in the electronic device to perform desired functions.

[0206] The memory 62 may include one or more computer program products, which may include various forms of computer-readable storage media, such as volatile memory and / or non-volatile memory. The volatile memory may, for example, include random access memory (RAM) and / or cache memory (cache), etc. The non-volatile memory may, for example, include read-only memory (ROM), a hard disk, a flash memory, etc. One or more computer program instructions may be stored on the computer-readable storage medium, and the processor 61 may execute the program instructions to implement the methods of the software programs of the various embodiments of the present invention described above and / or other desired functions. In one example, the electronic device may further include: an input device 63 and an output device 64, which are interconnected via a bus system and / or other forms of connection mechanisms (not shown).

[0207] In addition, the input device 63 may also include, for example, a keyboard, a mouse, etc.

[0208] The output device 64 can output various information to the outside. The output device 64 can include, for example, a display, a speaker, a printer, a communication network and a remote output device connected thereto.

[0209] Of course, to simplify, Figure 6 Only some of the components related to the present invention in the electronic device are shown, and components such as a bus, an input / output interface, etc. are omitted. In addition, the electronic device may further include any other appropriate components according to specific application conditions.

[0210] Exemplary computer program products and computer-readable storage media

[0211] In addition to the above-mentioned methods and devices, an embodiment of the present invention may also be a computer program product, which includes computer program instructions, which, when executed by a processor, enable the processor to perform the steps of the method according to various embodiments of the present invention described in the above "Exemplary Method" section of this specification.

[0212] The computer program product may be written in any combination of one or more programming languages to implement the operations of embodiments of the present invention, including object-oriented programming languages such as Java, C++, and conventional procedural programming languages such as C or similar programming languages. The program code may be executed entirely on the user's computing device, partially on the user's computing device, as a stand-alone software package, partially on the user's computing device and partially on a remote computing device, or entirely on a remote computing device or server.

[0213] In addition, an embodiment of the present invention may also be a computer-readable storage medium having computer program instructions stored thereon, which, when executed by a processor, enable the processor to execute the steps of the method according to various embodiments of the present invention described in the above "Exemplary Method" section of this specification.

[0214] The computer-readable storage medium can adopt any combination of one or more readable media. The readable medium can be a readable signal medium or a readable storage medium. The readable storage medium can, for example, include but is not limited to a system, system or device of electricity, magnetism, light, electromagnetic, infrared, or semiconductor, or any combination thereof. More specific examples (non-exhaustive list) of readable storage media include: an electrical connection with one or more wires, a portable disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination thereof.

[0215] The basic principles of the present invention have been described above in conjunction with specific embodiments. However, it should be noted that the advantages, strengths, and effects mentioned in the present invention are merely illustrative and non-limiting, and should not be construed as necessarily possessed by each embodiment of the present invention. Furthermore, the specific details disclosed above are provided for illustrative purposes and to facilitate understanding, and are not intended to be limiting. These details do not necessarily limit the present invention to being implemented using these specific details.

[0216] Each embodiment in this specification is described in a progressive manner, with each embodiment focusing on its differences from the other embodiments. References to the same or similar parts between the various embodiments are sufficient. For system embodiments, since they largely correspond to method embodiments, their description is relatively simple. For relevant parts, references to the description of the method embodiments are sufficient.

[0217] The block diagrams of the devices, systems, equipment, and systems involved in the present invention are merely illustrative examples and are not intended to require or imply that they must be connected, arranged, or configured in the manner shown in the block diagrams. As will be appreciated by those skilled in the art, these devices, systems, equipment, and systems can be connected, arranged, or configured in any manner. Words such as "including," "comprising," "having," and the like are open-ended words, meaning "including but not limited to," and can be used interchangeably therewith. The words "or" and "and" used herein refer to the words "and / or" and can be used interchangeably therewith, unless the context clearly indicates otherwise. The word "such as" used herein refers to the phrase "such as but not limited to," and can be used interchangeably therewith.

[0218] The method and system of the present invention may be implemented in many ways. For example, the method and system of the present invention may be implemented by software, hardware, firmware, or any combination of software, hardware, and firmware. The above sequence of steps for the method is for illustration only, and the steps of the method of the present invention are not limited to the sequence specifically described above, unless otherwise specified. In addition, in some embodiments, the present invention may also be implemented as a program recorded in a recording medium, which includes machine-readable instructions for implementing the method according to the present invention. Thus, the present invention also covers recording media that store programs for executing the method according to the present invention.

[0219] It should also be noted that, in the system, device and method of the present invention, each component or each step can be decomposed and / or recombined. These decompositions and / or recombinations should be regarded as equivalent schemes of the present invention. The above description of the disclosed aspects is provided to enable any technician in this field to make or use the present invention. Various modifications to these aspects will be very obvious to those skilled in the art, and the general principles defined here can be applied to other aspects without departing from the scope of the present invention. Therefore, the present invention is not intended to be limited to the aspects shown here, but according to the widest scope consistent with the principles disclosed here and novel features.

[0220] The above description has been presented for purposes of illustration and description. Furthermore, this description is not intended to limit the embodiments of the present invention to the forms disclosed herein. Although a number of example aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, alterations, additions, and sub-combinations thereof.

Claims

1. A method for calibrating a medium and low voltage current transformer without power outage, characterized in that: include: Measure the primary side original current signal of the current transformer to be tested using a pre-prepared mobile calibration platform; Injecting a reverse current of the same frequency as the injection current source of the current transformer to be tested into the current transformer to be tested, thereby offsetting the original current signal of the primary side of the current transformer to be tested; Using the injection current source to generate a heterofrequency current according to a preselected heterofrequency signal, and inputting the heterofrequency current into the primary side of the current transformer to be tested to perform heterofrequency current calibration, and collecting a secondary side output signal; performing error analysis on the current transformer to be tested based on the secondary side output signal, and determining an error analysis result; Based on the error analysis result, the calibration parameters of the current transformer to be measured are adjusted to re-perform the different-frequency current calibration until the error analysis result meets the preset requirements, thereby completing the calibration of the current transformer to be measured.

2. The method according to claim 1, characterized in that The original current signal includes: current amplitude, current frequency and current phase, and the primary side original current signal of the current transformer is measured using a pre-prepared mobile calibration platform, including: Measuring the current amplitude of the primary side current of the current transformer to be measured using a standard current transformer; Calculating and analyzing the current frequency of the primary side current using a frequency analyzer; and The phase measurement equipment is used to calculate, analyze and record the current phase of the primary side current.

3. The method according to claim 1, characterized in that Injecting a reverse current of the same frequency as the injection current source of the current transformer to be measured into the current transformer to be measured, so as to offset the original current signal of the primary side of the current transformer to be measured, comprising: generating a reverse current having the same frequency as the original current signal but opposite phase through the injection current source, wherein the amplitude and phase of the reverse current are precisely controlled by adjusting the injection current source; The generated reverse current is injected into the primary side of the current transformer to be measured, and the amplitude and phase of the reverse current are feedback-adjusted and superimposed on the original current signal to eliminate the original current signal on the primary side of the current transformer to be measured.

4. The method according to claim 3, characterized in that Injecting the generated reverse current into the primary side of the current transformer to be measured, and feedback-adjusting the amplitude and phase of the reverse current to be superimposed on the original current signal to eliminate the original current signal on the primary side of the current transformer to be measured, comprising: Injecting the generated reverse current into the primary side of the current transformer to be tested, and monitoring the output current signal of the secondary side of the current transformer to be tested; performing error analysis based on the output current signal to determine a cancellation error; The amplitude and phase of the reverse current are adjusted based on the cancellation error and re-injected into the primary side of the current transformer to be measured until the cancellation error meets a preset requirement to cancel the original current signal on the primary side of the current transformer to be measured.

5. The method according to claim 1, wherein Also includes: The calibration data of the current transformer to be tested is stored and a calibration report of the current transformer to be tested is generated, wherein the calibration report includes: error analysis before and after calibration, a calibration curve of the current transformer to be tested, corrected measurement parameters, and data during the calibration process.

6. The method according to claim 1, characterized in that Performing error analysis on the current transformer to be tested based on the secondary side output signal to determine an error analysis result includes: Calculating the frequency response and phase difference of the current transformer to be tested; Calculating a proportional error of the current transformer to be measured based on the frequency response, the secondary-side output signal, and the original current signal of the current transformer to be measured; A comprehensive error of the current transformer to be measured is determined according to the phase difference and the proportional error.

7. A non-stop calibration device for medium and low voltage current transformers, characterized in that: include: A measurement module is used to measure the primary side original current signal of the current transformer to be tested using a pre-prepared mobile calibration platform; a cancellation module, configured to inject a reverse current of the same frequency as the injection current source of the current transformer to be measured into the current transformer to be measured, so as to cancel the original current signal of the primary side of the current transformer to be measured; An input module, configured to generate a heterofrequency current using the injection current source according to a preselected heterofrequency signal, input the heterofrequency current into the primary side of the current transformer to be tested for heterofrequency current calibration, and collect a secondary side output signal; an analysis module, configured to perform error analysis on the current transformer to be tested based on the secondary side output signal, and determine an error analysis result; The calibration module is used to adjust the calibration parameters of the current transformer to be measured based on the error analysis result and re-perform the different-frequency current calibration until the error analysis result meets the preset requirements, thereby completing the calibration of the current transformer to be measured.

8. The device according to claim 7, characterized in that The original current signal includes: current amplitude, current frequency and current phase, and the measurement module includes: a measuring submodule, configured to measure the current amplitude of the primary side current of the current transformer to be measured using a standard current transformer; A first analysis submodule is configured to calculate and analyze the current frequency of the primary side current using a frequency analyzer; and The second analysis submodule is used to calculate, analyze and record the current phase of the primary side current using a phase measurement device.

9. A computer-readable storage medium, characterized in that The storage medium stores a computer program, and the computer program is used to execute the method according to any one of claims 1 to 6.

10. An electronic device, characterized in that: The electronic device comprises: processor; a memory for storing instructions executable by the processor; The processor is configured to read the executable instructions from the memory and execute the instructions to implement the method according to any one of claims 1 to 6.

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