Wideband Current Transformer Testing Methods, Apparatus, Equipment and Medium

Abstract

This invention discloses a method, apparatus, equipment, and medium for testing wideband current transformers, relating to the field of transformer calibration technology. First, a first frequency signal of a standard current and the current to be measured is simultaneously acquired. The frequency of the current to be measured is tracked in real time using a high-speed comparator, and a second frequency signal is accurately generated using digital frequency synthesis technology. Subsequently, analog mixing technology is used to shift the signal spectrum, generating a composite signal containing difference frequency and sum frequency components. Finally, a high-order digital filter accurately filters out the sum frequency component, allowing the measurement of only the difference frequency signal to obtain the ratio difference and angle difference of the wideband signal. By converting the measurement of the wideband signal into the measurement of a fixed low-frequency signal, the technical bottleneck of direct sampling in the high-frequency band by traditional sampling techniques is overcome, effectively improving the accuracy of the measured ratio difference and angle difference of wideband current transformers. While ensuring measurement accuracy, system power consumption and hardware costs are significantly reduced, ensuring the reliability and accuracy of wideband current transformer testing.

Description

Technical Field

[0001] This invention relates to the field of current transformer testing technology, and in particular to a broadband current transformer testing method, apparatus, equipment and medium. Background Technology

[0002] Currently, the testing of broadband current transformers mainly employs direct sampling technology. This technology first converts the standard current signal and the current signal under test output by the broadband current transformer into digital signals, and then performs synchronous sampling through a dual-channel analog-to-digital converter. However, this direct sampling method has inherent limitations: due to the performance limitations of the analog-to-digital converter chip, it is difficult to achieve a high sampling rate while ensuring high sampling accuracy. This contradiction can lead to the loss or distortion of signal details during the testing process, thus affecting the accuracy and reliability of the final test results. Summary of the Invention

[0003] In view of this, the present invention provides a broadband current transformer testing method, apparatus, electronic device and medium to solve the inherent limitations of the direct sampling method, which is mainly reflected in the difficulty of analog-to-digital conversion chips to simultaneously achieve sampling accuracy and sampling rate. This contradiction leads to the loss or distortion of signal details during the testing process, thereby affecting the accuracy and reliability of the final test results.

[0004] Firstly, a broadband current transformer testing method is provided, the method comprising:

[0005] Acquire the standard current signal, the current signal under test from the broadband current transformer, and the first frequency signal of the standard current signal and the current signal under test;

[0006] Based on the first frequency signal, a second frequency signal is generated through frequency synthesis technology, wherein the second frequency signal is equal to the difference between the first frequency signal and a preset frequency difference;

[0007] Based on the standard current signal, the current signal under test, the first frequency signal, and the second frequency signal, a first mixed analog signal and a second mixed analog signal are generated, and the sum-frequency component is filtered out from the first mixed analog signal and the second mixed analog signal to obtain a first low-frequency signal and a second low-frequency signal.

[0008] Based on the first low-frequency signal and the second low-frequency signal, the ratio difference and angle difference of the current signal under test relative to the standard current signal are determined.

[0009] Secondly, a wideband current transformer testing device is provided, the device comprising:

[0010] The acquisition module is used to acquire the standard current signal, the current signal under test from the broadband current transformer, and the first frequency signal of the standard current signal and the current signal under test.

[0011] The first generation module is used to generate a second frequency signal based on the first frequency signal using frequency synthesis technology, wherein the second frequency signal is equal to the difference between the first frequency signal and a preset frequency difference;

[0012] The second generation module is used to generate a first mixed analog signal and a second mixed analog signal based on the standard current signal, the current signal to be measured, the first frequency signal and the second frequency signal, and to filter out the sum-frequency component from the first mixed analog signal and the second mixed analog signal to obtain a first low-frequency signal and a second low-frequency signal.

[0013] The determination module is used to determine the ratio difference and angle difference of the current signal under test relative to the standard current signal based on the first low-frequency signal and the second low-frequency signal.

[0014] Thirdly, an electronic device is provided, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the steps of the above-described broadband current transformer testing method.

[0015] Fourthly, a computer-readable storage medium is provided, which stores a computer program that, when executed by a processor, implements the steps of the aforementioned broadband current transformer testing method.

[0016] The aforementioned method, apparatus, electronic equipment, and storage medium for testing broadband current transformers first synchronously acquire the first frequency signals of the standard current and the current under test. A high-speed comparator tracks the frequency of the signal under test in real time, and digital frequency synthesis technology is used to accurately generate the second frequency signal. Subsequently, analog mixing technology is employed to shift the signal spectrum, generating a composite signal containing difference frequency and sum frequency components. Finally, a high-order digital filter precisely filters out the sum frequency component, allowing the measurement of only the difference frequency signal to obtain the ratio and angle difference parameters of the broadband signal. By converting the measurement of the broadband signal into the measurement of a fixed low-frequency signal, the technical bottleneck of direct sampling in the high-frequency band by traditional sampling techniques is overcome, effectively improving the accuracy of the measured ratio and angle difference of broadband current transformers. While ensuring measurement accuracy, system power consumption and hardware costs are significantly reduced, ensuring the reliability and accuracy of broadband current transformer testing in smart grids. Attached Figure Description

[0017] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0018] Figure 1This is a flowchart illustrating a broadband current transformer testing method according to an embodiment of the present invention.

[0019] Figure 2 This is a schematic diagram of a broadband current transformer testing system according to an exemplary embodiment;

[0020] Figure 3 This is a schematic diagram of the structure of a broadband current transformer testing device in one embodiment of the present invention. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. It should be understood that the accompanying drawings in the present invention are only for illustrative and descriptive purposes and are not intended to limit the scope of protection of the present invention.

[0022] Furthermore, it should be understood that the schematic drawings are not drawn to scale. The flowcharts used in this invention illustrate operations implemented according to some embodiments of the invention. It should be understood that the operations in the flowcharts may not be implemented in sequence, and steps without logical contextual relationships may be reversed or performed simultaneously. Moreover, those skilled in the art, guided by the content of this invention, may add one or more other operations to the flowcharts, or remove one or more operations from the flowcharts.

[0023] Furthermore, the embodiments described herein are merely some, not all, of the embodiments of the invention. The components of the embodiments of the invention described and illustrated herein can typically be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0024] It should be noted that the term "comprising" will be used in the embodiments of the present invention to indicate the presence of a feature subsequently declared, but does not exclude the addition of other features. It should also be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0025] The following is a detailed description of this case, in conjunction with the relevant accompanying drawings in the instruction manual.

[0026] Please see Figure 1 This specification provides a broadband current transformer testing method, which specifically includes the following steps:

[0027] S10: Acquire the standard current signal, the current signal under test from the broadband current transformer, and the first frequency signal of the standard current signal and the current signal under test.

[0028] It is understood that the executing entity of this invention can be a broadband current transformer testing device, a terminal, or a server; no specific limitation is made here. This embodiment of the invention will be described using a server as an example.

[0029] In this step, the standard current signal refers to a known, precise current signal used as a reference during the calibration process. It is typically generated by a high-precision standard current source to provide a measurement reference. The current signal to be measured is the output signal of the broadband current transformer being tested. Since the standard current and the current to be measured have the same frequency characteristics, the frequency value can be extracted from both signals using a frequency measurement device and recorded as the first frequency signal.

[0030] S20: Based on the first frequency signal, a second frequency signal is generated through frequency synthesis technology, wherein the second frequency signal is equal to the difference between the first frequency signal and the preset frequency difference.

[0031] In this step, frequency synthesis technology can generate multiple frequency signals based on the input reference frequency signal. Processing the first frequency signal using this technology yields a new frequency signal, denoted as the second frequency signal. The frequency of the newly generated signal strictly satisfies the relationship: Second frequency signal = First frequency signal - Preset frequency difference.

[0032] Optionally, the preset frequency difference can be set to 10Hz. By setting a fixed frequency difference of 10Hz, the frequency difference between the first frequency signal and the second frequency signal is strictly locked at 10Hz, realizing the conversion of high-frequency signals to low-frequency signals. This frequency conversion method effectively reduces the difficulty of signal processing, making low-frequency signals easier to accurately test and quantify, thereby significantly improving the resolution and accuracy of the measurement and ensuring the reliability of the final measurement results.

[0033] In one embodiment of this application, a specific second frequency signal generation scheme is provided. In S20, that is, based on the first frequency signal, the second frequency signal is generated through frequency synthesis technology, specifically including the following steps S21-S23:

[0034] S21: The standard current signal is tracked by an analog comparator to generate a square wave signal synchronized with the first frequency signal.

[0035] In this step, the standard current signal is converted into a square wave signal with the same frequency as the first frequency signal by an analog comparator. This square wave signal serves as the reference clock input of the direct frequency synthesizer (DDS), providing a synchronization reference for the system, thereby ensuring that the second frequency signal output by the DDS maintains a strict frequency correlation with the original input signal.

[0036] S22: Input the square wave signal to the direct frequency synthesizer, and generate the system clock frequency signal through the internal clock multiplication function of the direct frequency synthesizer.

[0037] In this step, after the DDS receives a square wave input synchronized with the first frequency signal, the DDS uses its built-in frequency multiplier circuit to multiply the frequency of the input square wave signal, thereby generating a high-precision system clock frequency signal. This effectively ensures that the frequency synthesis process has excellent accuracy and stability.

[0038] S23: Generate a second frequency signal based on the system clock frequency signal and the preset frequency division setting of the direct frequency synthesizer.

[0039] In this step, a pre-configured frequency division setting is set in the direct frequency synthesizer according to a preset frequency difference. The direct frequency synthesizer, based on the system clock frequency signal, performs precise frequency division processing according to the preset frequency division setting through its internal frequency division circuit, and finally outputs the required second frequency signal.

[0040] In the above manner, through the coordinated operation of an analog comparator and a direct frequency synthesizer, the standard current signal is sequentially processed through waveform conversion, frequency multiplication, and frequency division to ultimately generate a precise second frequency signal.

[0041] In one embodiment of this application, a specific second frequency signal verification scheme is provided. After S20, that is, after generating the second frequency signal based on the first frequency signal using a direct frequency synthesizer, the following steps are further included:

[0042] Obtain the difference between the first frequency signal and the second frequency signal;

[0043] Determine whether the difference is equal to the preset frequency difference;

[0044] If the difference is not equal to the preset frequency difference, the second frequency signal is adjusted by adjusting the preset frequency division setting until the difference between the first frequency signal and the second frequency signal is equal to the preset frequency difference.

[0045] In this embodiment, to ensure that the frequency difference between the first and second frequency signals is strictly locked to a preset frequency difference, the difference between the first and second frequency signals is obtained by subtracting the frequency value of the second frequency signal from the frequency value of the first frequency signal, and then compared with the preset frequency difference. If they match, the current frequency relationship conforms to the design specifications; if there is a deviation, adjustment is required. Since the direct frequency synthesizer generates the second frequency signal based on the system clock frequency and a preset frequency division setting, when the measured difference does not match the preset frequency difference, the output of the second frequency signal is precisely corrected by dynamically adjusting the preset frequency division setting until the difference between the first and second frequency signals perfectly matches the preset frequency difference, thereby achieving high-precision frequency control.

[0046] S30: Based on the standard current signal, the current signal to be measured, the first frequency signal, and the second frequency signal, generate a first mixed analog signal and a second mixed analog signal, and filter out the sum-frequency components in the first mixed analog signal and the second mixed analog signal to obtain a first low-frequency signal and a second low-frequency signal.

[0047] In this step, the standard current signal is mixed with the second frequency signal. Then, the sum frequency component is filtered out, and its difference frequency component is extracted as the first low-frequency signal; using the same processing method, the current signal to be measured is mixed with the second frequency signal, and the difference frequency component is retained to obtain the second low-frequency signal.

[0048] In one embodiment of this application, a specific low-frequency signal generation scheme is provided. In S30, a first low-frequency signal and a second low-frequency signal are generated based on a standard current signal, a current signal to be measured, a first frequency signal, and a second frequency signal. Specifically, this includes the following steps S31-S32:

[0049] S31: Based on the standard current signal, the current signal to be measured, the first frequency signal, and the second frequency signal, a first mixed analog signal and a second mixed analog signal are obtained through analog mixing technology, wherein the mixed analog signal includes a difference frequency component and a sum frequency component.

[0050] In this step, the standard current signal is mixed with the second frequency signal to generate a first mixed analog signal. Similarly, the current signal to be measured is mixed with the second frequency signal to form a second mixed analog signal. During the mixing process, when two signals of different frequencies interact, a difference frequency component and a sum frequency component are generated. During the mixing process, the interaction of the signals generates two main frequency components: a difference frequency component (frequency value is the difference between the first frequency signal and the second frequency signal) and a sum frequency component (frequency value is the sum of the first frequency component and the second frequency signal).

[0051] The above method converts the high-frequency standard current signal and the current signal under test into a mixed analog signal containing difference frequency and sum frequency, which facilitates subsequent signal processing and analysis.

[0052] In one embodiment of this application, a specific hybrid analog signal generation scheme is provided. In S31, based on a standard current signal, a current signal to be measured, a first frequency signal, and a second frequency signal, a first hybrid analog signal and a second hybrid analog signal are obtained through analog mixing technology. Specifically, this includes the following steps S311-S312:

[0053] S311: Multiply the first frequency signal of the standard current signal with the second frequency signal to obtain the first hybrid analog signal corresponding to the standard current signal.

[0054] In this step, an analog multiplier is used to linearly mix the first frequency signal and the second frequency signal of the standard current signal to generate a first mixed analog signal.

[0055] S312: Multiply the first frequency signal of the current signal to be measured with the second frequency signal to obtain the second hybrid analog signal corresponding to the current signal to be measured.

[0056] In this step, an analog multiplier is used to linearly mix the first frequency signal and the second frequency signal of the current signal to be measured to generate a second mixed analog signal.

[0057] S32: Perform analog-to-digital conversion on the first mixed analog signal and the second mixed analog signal, and filter out the sum-frequency components based on the preset sampling rate to obtain the first low-frequency signal corresponding to the standard current signal and the second low-frequency signal corresponding to the current signal to be measured.

[0058] In this step, the analog-to-digital converter (ADC) discretizes the analog signal into a digital signal. When the first and second mixed analog signals are digitized using the ADC, a pre-set sampling rate is required to ensure complete acquisition of the signal information. Since the sum frequency component in the mixed analog signal is significantly higher than the difference frequency component, a digital low-pass filter designed based on the preset sampling rate can effectively filter out the high-frequency sum frequency component, thereby extracting the low-frequency difference frequency component corresponding to the standard current signal (i.e., the first low-frequency signal) and the low-frequency difference frequency component corresponding to the current signal under test (i.e., the second low-frequency signal).

[0059] By using the above method, the standard current signal and the current signal under test are converted into corresponding low-frequency signals, which not only facilitates subsequent processing and analysis but also significantly reduces the amount of data and computational complexity. While ensuring signal integrity, this effectively improves the efficiency and accuracy of signal processing.

[0060] In one embodiment of this application, a specific low-frequency signal acquisition scheme is provided. In S32, the first mixed analog signal and the second mixed analog signal are converted from analog to digital, and high-frequency components are filtered out based on a preset sampling rate to obtain the first low-frequency signal corresponding to the standard current signal and the second low-frequency signal corresponding to the current signal to be measured. Specifically, it includes the following steps S321-S325:

[0061] S321: Based on the trigonometric identity, the first mixed analog signal is decomposed to obtain the first difference frequency component and the first sum frequency component.

[0062] S322: Based on the trigonometric identity, the second hybrid analog signal is decomposed to obtain the second difference frequency component and the second sum frequency component.

[0063] For steps S321-S322, based on the product-to-sum principle of trigonometric functions, the first mixed analog signal is decomposed to obtain two characteristic frequency components: the first difference frequency component and the first sum frequency component. Similarly, based on the product-to-sum principle of trigonometric functions, the second mixed analog signal is decomposed to obtain two characteristic frequency components: the second difference frequency component and the second sum frequency component.

[0064] S323: Perform analog-to-digital conversion on the first mixed analog signal and the second mixed analog signal to generate a first digital signal and a second digital signal.

[0065] In this step, the analog-to-digital converter (ADC) discretizes the analog input signal (first mixed analog signal and second mixed analog signal) at a fixed sampling period, and converts the sampled analog values ​​into digital codes through quantization, thereby generating a first digital signal representing the standard current signal and a second digital signal representing the standard measured current signal, respectively.

[0066] The above method achieves a precise mapping from analog signals to the digital domain.

[0067] S324: The first digital signal is downsampled to the target rate using a digital filter, the first sum frequency component of the first digital signal is filtered out, and the digital signal corresponding to the first difference frequency component is output, which is denoted as the first low frequency signal.

[0068] In this step, downsampling refers to reducing the sampling rate of the signal through digital filtering and decimation techniques. When downsampling the first digital signal, high-frequency components are first filtered out using a digital filter, then the sampling points are proportionally decimated, ultimately reducing the sampling rate to the target rate. This processing method significantly reduces the amount of data, lowering the system's processing load and computational complexity. Furthermore, while retaining effective low-frequency information, it optimizes signal characteristics by removing redundant high-frequency components, thus better meeting the needs of subsequent low-frequency signal processing.

[0069] Furthermore, employing a digital low-pass filter to perform frequency domain filtering on the signal effectively removes the first sum-frequency component while fully preserving the digital signal characteristics corresponding to the first difference-frequency component. The first low-frequency signal output by this processing method fully retains the amplitude and phase characteristics of the original difference-frequency signal: the amplitude parameter characterizes the signal intensity characteristics, and the phase parameter reflects the signal timing relationship. These two key parameters provide an important basis for subsequent accurate signal analysis and processing.

[0070] By using the above method, selective processing of the frequency domain is performed, which achieves optimized extraction of signal features while ensuring the integrity of signal features.

[0071] S325: The second digital signal is downsampled to the target rate using a digital filter, the second sum frequency component of the second digital signal is filtered out, and the digital signal corresponding to the second difference frequency component is output, which is denoted as the second low frequency signal.

[0072] The digital signal includes the amplitude and phase information of the difference frequency signal.

[0073] In this step, the second digital signal is downsampled to reduce its sampling rate to the target rate, effectively reducing the amount of data while meeting the requirements of subsequent processing. Then, the second sum-frequency component is filtered out using a digital filter (such as a low-pass filter), accurately extracting the digital signal corresponding to the second difference-frequency component, i.e., the second low-frequency signal. This signal fully preserves the amplitude intensity characteristics and phase timing characteristics of the second difference-frequency signal, providing a reliable data foundation for subsequent accurate signal analysis.

[0074] The above method converts the mixed analog signal into a low-frequency digital signal containing difference frequency information, which facilitates more accurate signal analysis and measurement in the future.

[0075] S40: Based on the first low-frequency signal and the second low-frequency signal, determine the ratio difference and angle difference of the current signal under test relative to the standard current signal.

[0076] In this step, ratio error and phase angle error are two key metrological parameters in the performance testing of broadband current transformers. Ratio error characterizes the amplitude deviation between the measured current signal and the standard current signal. By analyzing the amplitude difference between the first and second low-frequency signals, the amplitude error of the measured current signal can be accurately calculated. Phase angle error, on the other hand, reflects the phase shift between the measured current signal and the standard current signal. By measuring the phase difference between the first and second low-frequency signals, the phase deviation of the measured current signal can be directly determined. Ultimately, based on the accurate measurement results of ratio error and phase angle error, the metrological stability and operating performance of the broadband current transformer can be effectively evaluated.

[0077] In one embodiment of this application, a specific scheme for calculating the ratio difference and angle difference is provided. In S40, that is, based on the first low-frequency signal and the second low-frequency signal, the ratio difference and angle difference of the current signal to be measured relative to the standard current signal are determined, specifically including the following steps S41-S44:

[0078] S41: Extract the first amplitude and first phase of the first low-frequency signal.

[0079] S42: Extract the second amplitude and second phase of the second low-frequency signal.

[0080] For steps S41-S42, the first low-frequency signal, as a representation of the standard current signal after system processing, fully preserves the signal characteristics of the standard current signal. Using digital signal processing methods such as Fast Fourier Transform (FFT) or correlation algorithms, its amplitude and phase parameters can be accurately extracted from the first low-frequency signal, denoted as the first amplitude and the first phase, respectively. These two parameters constitute the reference values ​​for the standard current signal. Similarly, the second low-frequency signal characterizes the features of the current signal under test after the same processing flow. Through the same algorithm, its corresponding second amplitude and second phase parameters can be extracted, fully reflecting the signal characteristics of the channel under test.

[0081] S43: Calculate the ratio difference based on the first amplitude and the second amplitude.

[0082] In this step, the difference is used to measure the degree of deviation of the amplitude of the tested channel signal from the amplitude of the standard current signal. The calculation formula is:

[0083] .

[0084] Substitute the first and second amplitude values ​​into the ratio difference calculation formula to reflect the relative difference between the amplitude of the tested channel signal and the amplitude of the standard current signal.

[0085] S44: Calculate the angle difference based on the first phase and the second phase.

[0086] In this step, the phase difference is used to measure the degree of deviation of the phase of the tested channel signal relative to the phase of the standard current signal. The calculation formula is:

[0087] Angular difference = second phase - first phase;

[0088] Substituting the first and second phases into the angle difference calculation formula reflects whether the phase relationship between current and voltage meets the requirements.

[0089] By calculating the ratio difference and angle difference using the above methods, the difference between the tested channel signal and the standard current signal can be comprehensively evaluated, thereby accurately judging and calibrating the performance of the broadband current transformer.

[0090] As can be seen, in the above scheme, the first frequency signals of the standard current and the current under test are first acquired synchronously. A high-speed comparator tracks the frequency of the signal under test in real time, and digital frequency synthesis technology is used to accurately generate the second frequency signal. Subsequently, analog mixing technology is used to shift the signal spectrum, generating a composite signal containing difference frequency and sum frequency components. Finally, a high-order digital filter accurately filters out the sum frequency component, allowing the measurement of only the difference frequency signal to obtain the ratio and angle difference parameters of the wideband signal. By converting the measurement of the wideband signal into the measurement of a fixed low-frequency signal, the technical bottleneck of direct sampling in the high-frequency band by traditional sampling techniques is overcome, effectively improving the accuracy of the measured ratio and angle difference of the wideband current transformer. While ensuring measurement accuracy, system power consumption and hardware costs are significantly reduced, ensuring the reliability and accuracy of wideband current transformer testing in smart grids.

[0091] In practical applications, with the continuous and rapid growth of new energy power generation such as photovoltaics and wind power, and the grid connection of a large number of rectifiers and nonlinear loads such as high-speed rail, harmonic currents with frequencies as high as 2kHz or even higher have appeared in the power system. The "double high" problem of high-proportion new energy access and high-proportion power electronic equipment application is becoming increasingly prominent, leading to increasingly complex dynamic characteristics of the power grid and a significant increase in measurement errors. The resulting broadband power metering inaccuracy problem is highly likely to cause disputes in power settlement and trade. Both power quality assessment and power metering rely on the acquisition of signals from the secondary side of current transformers; therefore, only by ensuring the accurate transmission of broadband signals by current transformers can the accuracy of measurement signals be guaranteed from the source. To ensure the accuracy of broadband current transformer test results, this application proposes a broadband current transformer test system to implement the aforementioned broadband current transformer test method, such as... Figure 2 The diagram shows the structure of a wideband current transformer testing system. The system includes: a multi-channel AD synchronous conversion module U1, analog front-end drivers A1 and A2, analog multipliers M1 and M2, an analog comparator A3, wideband shunts R1 and R2, a direct digital frequency synthesizer (DDS) U5, a DSP (Digital Signal Processor) module U2, an LCD display U3, a keypad module U4, and a resistor R3. The specific connection method is as follows:

[0092] The input terminals of wideband shunts R1 and R2 are connected to the external current to be measured Ix and the standard current Ib respectively via copper wires. The output terminals of wideband shunts R1 and R2 are connected to the input terminals of analog multipliers M1 and M2 respectively, and the output of wideband shunt R2 is also connected to the input terminal of analog comparator A3.

[0093] The output of analog comparator A3 is connected to the reference clock input CLKREF (Reference Clock) of direct digital frequency synthesizer U5. The clock output CLKOUT of direct digital frequency synthesizer U5 is converted into a voltage signal through resistor R3 and simultaneously connected to the inputs of analog multipliers M1 and M2, with its low potential (GND) grounded.

[0094] The outputs of analog multipliers M1 and M2 are connected to the inputs of analog front-end drivers A1 and A2, respectively, and their low-potential terminals (GND) are grounded.

[0095] The output terminals of analog front-end drivers A1 and A2 are connected to CH1 (channel 1) and CH2 (channel 2) of the multi-channel AD synchronous conversion module U1, respectively, and the low-potential terminals are grounded.

[0096] In the DSP processing module, the multi-channel AD synchronous conversion module U1 communicates with the DSP processing module via an SPI interface, and the direct digital frequency synthesizer U5 is also connected to the DSP processing module's SPI interface via an SPI interface. The LCD display U3 is connected to the DSP processing module via an AMC (Asynchronous Memory Bus) interface. The KEY keyboard module U4 interacts with the DSP processing module via six GPIO (General Purpose Input / Output) interfaces.

[0097] The wideband shunts R1 and R2 are used to achieve wideband conversion from high current to low voltage signals. In this embodiment, the conversion range is 0-1A input current. The operating frequency band is 50Hz-100kHz. A Fluke A40B-1A shunt is selected, with an actual accuracy of 50ppm.

[0098] The analog front-end drives A1 and A2 to adapt the output of the analog multiplier to the drive current and voltage of the multi-channel AD synchronous conversion module U1. THD (Total Harmonic Distortion) ≥120dB. Optional op-amp OPA1632 (measured THD 130dB).

[0099] Analog comparator A3, response time: ≤5μs, LM339 optional (actual switching time 1µs).

[0100] The multi-channel synchronous AD conversion module U1 has an integration error of no less than ±0.01%, operates on the sigma-delta AD principle, and incorporates a robust built-in filter. This embodiment selects the 24-bit 8-channel synchronous sigma-delta AD converter ADS1278, with a typical integration error of ±0.0003%, a maximum sampling rate of 128KSPS, and uses the ADR441B reference voltage of 2.5V (temperature drift less than 3ppm).

[0101] The DSP processing module U2 has at least two SPI interfaces, six I / O interfaces, and one AMC interface. It can optionally consist of an ADI BF609 chip and its peripherals. The chip integrates numerous peripherals, including one SPI interface, 16 general-purpose I / O ports, an AMC interface (asynchronous memory interface), and 256MB YTE DRAM, used to implement the core algorithms, task scheduling, display, and input functions of the embodiments described in this application.

[0102] Human-computer interaction module: LCD display U3, interface method: AMC bus driven. Keyboard module U4 is a simple keyboard with a 6-key layout. The inputs are connected to the 6 I / O pins of the DSP processing module U2 for starting and stopping the test and inputting the frequency to be tested.

[0103] The U5 direct digital frequency synthesizer is used for precise frequency generation (f1 to f1-10Hz) and clock multiplication (≥64x). The AD9913 chip is optional.

[0104] The current-to-voltage conversion resistor R3 is a 1kΩ high-precision resistor with a temperature drift of 10ppm.

[0105] When testing a broadband current transformer, the testing steps are as follows:

[0106] First, the operator inputs the desired wideband frequency f1 (the frequency of the test current source) via the keyboard module U4. The DSP processing module U2 controls the DDS to output the corresponding frequency f2 via the SPI interface. Then, the DSP processing module U2 acquires data from the multi-channel AD synchronous conversion module U1 at a 40Hz sampling rate via the SPI interface. U1 automatically filters out the (f1+f2) frequency component at the 40Hz sampling rate. Subsequently, the DSP processing module U2 calculates the ratio and angle difference of the wideband signal f1 in real time, completing the measurement data analysis and processing. Finally, the measurement results are output to the LCD display U4 via the AMC bus interface.

[0107] Specifically, the working principle of the broadband current transformer testing system is as follows:

[0108] Let the standard current signal be:

[0109] (1)

[0110] Where Ib is the instantaneous value of the standard current signal; IbA is the amplitude of the standard current signal; f1 is the first frequency signal of the standard current signal; and t is the time variable. This is the initial phase angle of the standard current signal.

[0111] Let the current signal to be measured be:

[0112] (2)

[0113] Where Ix is the instantaneous value of the current signal to be measured; IxA is the amplitude of the current signal to be measured; f1 is the first frequency signal of the current signal to be measured; and t is the time variable. The initial phase angle of the current signal to be measured is denoted as .

[0114] The formula for calculating the ratio difference of a broadband current transformer is:

[0115] (3)

[0116] Where ferr is the ratio difference.

[0117] The formula for calculating the angle difference of a broadband current transformer is:

[0118] (4)

[0119] in, The difference is the angle.

[0120] Analog comparator A3 converts the input analog signal into a square wave signal of the same frequency (f1), which serves as the reference clock source for the DDS.

[0121] The DDS internally multiplies the input clock of f1 by N times to form the system's internal clock frequency fsysclk = N × f1.

[0122] Then the frequency f2 of the DDS clock output CLKOUT is:

[0123] (5)

[0124] Where f2 is the second frequency signal output by the DDS; FTW is the preset frequency division setting of the DDS; N is the clock multiplication factor inside the DDS; f1 is the first frequency signal; 2 32 fsysclk is the 32-bit frequency resolution of DDS; fsysclk is the internal clock frequency of DDS.

[0125] Let f2 = f1 - 10, meaning the output frequency f2 of the DDS is set to be 10 Hz less than the input frequency f1. Then the frequency relationship is:

[0126] (6)

[0127] Therefore, the FTW calculation formula is:

[0128] (7)

[0129] The frequency control mechanism based on formula (7) can accurately set the DDS output frequency f2=f1-10Hz.

[0130] Let the reference signal output by the DDS be:

[0131] (8)

[0132] Where Uref is the instantaneous value of the reference signal output by the DDS; UrefA is the amplitude of the reference signal; The initial phase of the reference signal.

[0133] The output waveform of analog multiplier M1 is the product of formulas (1) and (8), and the output waveform of M2 is the product of formulas (2) and (8). After product-to-difference operations, the final output signal is obtained:

[0134] (9)

[0135] Where IbMP is the first mixed analog signal output by analog multiplier M1; f1-f2 is the difference frequency component; and f1+f2 is the sum frequency component.

[0136] (10)

[0137] Wherein, IxMP is the second mixed analog signal output by analog multiplier M2.

[0138] The difference frequency signal (f1-f2) = 10Hz is precisely set by DDS, as shown in formulas (6) and (7). The multi-channel AD synchronous conversion module U1 uses the ADS1278 chip, configured with a sampling rate of 40Hz, and its passband characteristic is 0.453×40=18.12Hz, which fully meets the sampling requirements of the 10Hz signal. The system cutoff frequency is set to 0.49×40Hz=19.6Hz. Since the test frequencies in this application embodiment are all above 50Hz, the attenuation of the signal in this frequency band by the module exceeds 100dB, and its influence can be completely ignored. That is, the waveform of (f1+f2) is completely attenuated. =f1-f2 is set to 10Hz. Therefore, the actual signal waveform acquired by the multi-channel AD synchronous conversion module U1 is shown in formula (11) and formula (12). This design ensures the accurate extraction of the difference frequency signal and the effective suppression of high-frequency interference.

[0139]

[0140] Wherein, IbMP is the first low-frequency signal after filtering; This represents the phase difference between the standard current and the reference signal.

[0141]

[0142] Where IxMP is the filtered second low-frequency signal.

[0143] The difference frequency testing method used in this application embodiment achieves high-precision wideband measurement through the signal processing mechanism shown in formulas (11) and (12). The system accurately tracks and sets a fixed difference frequency of 10Hz, uses an analog multiplier to perform multiplication of two frequency signals, and outputs a composite signal containing the difference frequency (f1-f2) and the sum frequency (f1+f2). With the help of the high-performance anti-aliasing filter built into the multi-channel AD synchronous conversion module U1, the sum frequency (f1+f2) component can be effectively filtered out, and only the 10Hz difference frequency signal is retained for subsequent processing. The ratio difference and angle difference of the standard current and the current under test at any frequency f2 are accurately measured. The system sampling rate requirement is greatly reduced, and only a 10Hz sampling rate is needed to complete the high-precision measurement. Moreover, through the synergistic optimization of analog domain preprocessing and digital domain filtering, the system power consumption and hardware cost are significantly reduced while ensuring measurement accuracy.

[0144] By synchronously sampling and demodulating the IbMP mixing signal, the amplitude and phase characteristic parameters of the standard current signal are accurately extracted.

[0145]

[0146] Wherein, IbA is the amplitude measurement result of the standard current signal after multi-channel AD synchronous sampling.

[0147]

[0148] in, This is the phase measurement result of the standard current signal after multi-channel AD synchronous sampling.

[0149] By synchronously sampling and demodulating the mixing signal IxMP, the amplitude and phase characteristic parameters of the current signal under test are accurately extracted.

[0150]

[0151] Wherein, IxA is the amplitude measurement result of the current signal under test after multi-channel AD synchronous sampling.

[0152]

[0153] in, This is the phase measurement result of the current signal under test after multi-channel AD synchronous sampling.

[0154] Therefore, the ratio error of the broadband current transformer is:

[0155]

[0156] It should be noted that the amplitudes IxA and IbA of the mixing signal both contain the same scaling factor UrefA / 2, which is automatically canceled out during the ratio difference calculation.

[0157] The phase angle difference of a broadband current transformer is:

[0158]

[0159] It should be noted that the influence of the reference signal phase φref is automatically eliminated by the signal processing algorithm, and only the relative difference between the phase φx of the current signal under test and the phase φb of the standard current signal needs to be accurately measured.

[0160] By comparing and analyzing the mathematical relationship between formulas (17)-(18) and formulas (3)-(4), it can be clearly seen that the core testing principle of this application embodiment is that the system indirectly achieves high-precision testing of the amplitude ratio difference and phase angle difference of the original frequency f2 signal by accurately measuring the amplitude and phase characteristics of the difference frequency component (f1-f2).

[0161] The wideband current transformer testing system provided in this application firstly employs a DDS chip with a built-in clock multiplier to track the frequency f1 of the signal under test in real time through a comparator and accurately generate a reference signal f2 = f1 - 10Hz. Secondly, a spectrum shifting operation is performed using an analog multiplier to generate two frequency bands: f1 - f2 (10Hz) and f1 + f2. Then, a high-performance digital filter built into a Σ-Δ ADC automatically filters out sum and difference frequency components, retaining only the 10Hz difference frequency signal for measurement. This achieves the goal of testing the f1 of a high-frequency signal by testing a low-frequency signal of f1 - f2 = 10Hz. By indirectly achieving high-frequency signal testing through low-frequency measurement, the measurement of high-frequency signals of 100kHz and above is converted into a fixed 10Hz low-frequency measurement, breaking through the technical bottleneck of traditional sampling systems that directly sample high-frequency signals. Benefiting from the wideband characteristics (up to 100MHz and above) of the DDS and analog multiplier, and in conjunction with a wideband shunt, it can theoretically achieve accurate measurement of frequencies above 100kHz, an order of magnitude improvement over the existing mainstream 10kHz test bandwidth. Furthermore, the system only requires a 40Hz sampling rate to process the 10Hz difference frequency signal, which significantly reduces the requirements for DSP processing capabilities and performance, making the system feature low power consumption (typical value <5W) and obvious cost advantages, while ensuring measurement accuracy.

[0162] In one embodiment, a broadband current transformer testing device is provided, which corresponds one-to-one with the broadband current transformer testing method described in the above embodiments. For example... Figure 3 As shown, the broadband current transformer testing device 100 includes: an acquisition module 101, a first generation module 102, a second generation module 103, and a determination module 104. Detailed descriptions of each functional module are as follows:

[0163] The acquisition module 101 is used to acquire the standard current signal, the current signal under test of the broadband current transformer, and the first frequency signal of the standard current signal and the current signal under test.

[0164] The first generation module 102 is used to generate a second frequency signal based on the first frequency signal using frequency synthesis technology, wherein the second frequency signal is equal to the difference between the first frequency signal and a preset frequency difference.

[0165] The second generation module 103 is used to generate a first mixed analog signal and a second mixed analog signal based on a standard current signal, a current signal to be measured, a first frequency signal and a second frequency signal, and to filter out the sum-frequency component from the first mixed analog signal and the second mixed analog signal to obtain a first low-frequency signal and a second low-frequency signal.

[0166] The determination module 104 is used to determine the ratio difference and angle difference of the current signal under test relative to the standard current signal based on the first low-frequency signal and the second low-frequency signal.

[0167] In one embodiment, the first generation module 102 is specifically used for:

[0168] A standard current signal is tracked using an analog comparator to generate a square wave signal synchronized with the first frequency signal.

[0169] The square wave signal is input to the direct frequency synthesizer, and the system clock frequency signal is generated by the internal clock multiplication function of the direct frequency synthesizer.

[0170] A second frequency signal is generated based on the system clock frequency signal and the preset frequency division setting of the direct frequency synthesizer.

[0171] In one embodiment, the acquisition module 101 is further configured to: acquire the difference between the first frequency signal and the second frequency signal.

[0172] In one embodiment, the device further includes:

[0173] The judgment module is used to determine whether the difference is equal to the preset frequency difference;

[0174] The adjustment module is used to adjust the second frequency signal by adjusting the preset frequency division setting value if the difference is not equal to the preset frequency difference, until the difference between the first frequency signal and the second frequency signal is equal to the preset frequency difference.

[0175] In one embodiment, the second generation module 103 is specifically used for:

[0176] Based on the standard current signal, the current signal under test, the first frequency signal, and the second frequency signal, a first mixed analog signal and a second mixed analog signal are obtained through analog mixing technology. The mixed analog signal includes a difference frequency component and a sum frequency component.

[0177] The first and second mixed analog signals are converted from analog to digital, and the sum and frequency components are filtered out based on a preset sampling rate to obtain the first low-frequency signal corresponding to the standard current signal and the second low-frequency signal corresponding to the current signal under test.

[0178] In one embodiment, the second generation module 103 is further configured to:

[0179] Multiply the first frequency signal of the standard current signal with the second frequency signal to obtain the first hybrid analog signal corresponding to the standard current signal;

[0180] Multiply the first frequency signal of the current signal to be measured with the second frequency signal to obtain the second hybrid analog signal corresponding to the current signal to be measured.

[0181] In one embodiment, the second generation module 103 is further configured to:

[0182] Based on the trigonometric identity, the first hybrid analog signal is decomposed to obtain the first difference frequency component and the first sum frequency component.

[0183] Based on the trigonometric identity, the second hybrid analog signal is decomposed to obtain the second difference frequency component and the second sum frequency component.

[0184] The first mixed analog signal and the second mixed analog signal are converted from analog to digital to generate a first digital signal and a second digital signal.

[0185] The first digital signal is downsampled to the target rate by a digital filter, the first sum frequency component of the first digital signal is filtered out, and the digital signal corresponding to the first difference frequency component is output, which is denoted as the first low frequency signal.

[0186] The second digital signal is downsampled to the target rate by a digital filter, the second sum frequency component of the second digital signal is filtered out, and the digital signal corresponding to the second difference frequency component is output, which is denoted as the second low frequency signal.

[0187] The digital signal includes the amplitude and phase information of the difference frequency signal.

[0188] In one embodiment, the determining module 104 is specifically used for:

[0189] Extract the first amplitude and first phase of the first low-frequency signal;

[0190] Extract the second amplitude and second phase of the second low-frequency signal;

[0191] Calculate the ratio difference based on the first and second amplitude values;

[0192] The angular difference is calculated based on the first phase and the second phase.

[0193] This invention provides a wideband current transformer testing device 100. First, it synchronously acquires the first frequency signals of a standard current and the current under test. A high-speed comparator tracks the frequency of the signal under test in real time, and digital frequency synthesis technology is used to accurately generate a second frequency signal. Subsequently, analog mixing technology is used to shift the signal spectrum, generating a composite signal containing difference frequency and sum frequency components. Finally, a high-order digital filter accurately filters out the sum frequency component, allowing the measurement of only the difference frequency signal to obtain the ratio and angle difference parameters of the wideband signal. By converting the measurement of the wideband signal into the measurement of a fixed low-frequency signal, it overcomes the technical bottleneck of direct sampling in the high-frequency band using traditional sampling techniques, effectively improving the accuracy of the measured ratio and angle difference of the wideband current transformer. While ensuring measurement accuracy, it significantly reduces system power consumption and hardware costs, ensuring the reliability and accuracy of wideband current transformer testing in smart grids.

[0194] Specific limitations regarding the broadband current transformer testing device can be found in the limitations of the broadband current transformer testing method described above, and will not be repeated here. Each module in the aforementioned broadband current transformer testing device can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in the processor of the electronic device in hardware form or independently of the processor, or stored in the memory of the electronic device in software form, so that the processor can call and execute the corresponding operations of each module.

[0195] In one embodiment, an electronic device is provided, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the above-described wideband current transformer testing method.

[0196] In one embodiment, a computer-readable storage medium is provided, which stores a computer program that, when executed by a processor, implements the above-described broadband current transformer testing method.

[0197] It should be noted that the functions or steps that can be implemented by the computer-readable storage medium or electronic device described above can be referred to the relevant descriptions on the server side and client side in the foregoing method embodiments. To avoid repetition, they will not be described one by one here.

[0198] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. Any references to memory, storage, databases, or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory. Non-volatile memory can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memory can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in various forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), dual data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link DRAM (SLDRAM), Rambus direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM), etc.

[0199] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the above-described division of functional units and modules is used as an example. In practical applications, the above functions can be assigned to different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above.

[0200] The above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included within the protection scope of the present invention.

Claims

1. A broadband current transformer testing method, characterized in that, include: Acquire a standard current signal, a test current signal from a broadband current transformer, and a first frequency signal of the standard current signal and the test current signal; Based on the first frequency signal, a second frequency signal is generated by frequency synthesis technology, wherein the second frequency signal is equal to the difference between the first frequency signal and a preset frequency difference; Based on the standard current signal, the current signal to be measured, the first frequency signal, and the second frequency signal, a first mixed analog signal and a second mixed analog signal are generated, and the sum-frequency component is filtered out from the first mixed analog signal and the second mixed analog signal to obtain a first low-frequency signal and a second low-frequency signal. Based on the first low-frequency signal and the second low-frequency signal, determine the ratio difference and angle difference of the current signal under test relative to the standard current signal; The step of generating a first hybrid analog signal and a second hybrid analog signal based on the standard current signal, the current signal under test, the first frequency signal, and the second frequency signal specifically includes: Based on the standard current signal, the current signal under test, the first frequency signal, and the second frequency signal, a first mixed analog signal and a second mixed analog signal are obtained through analog mixing technology, wherein the mixed analog signal includes a difference frequency component and a sum frequency component; The step of obtaining a first mixed analog signal and a second mixed analog signal based on the standard current signal, the current signal under test, the first frequency signal, and the second frequency signal using analog mixing technology specifically includes: Multiplying the first frequency signal of the standard current signal with the second frequency signal yields the first hybrid analog signal corresponding to the standard current signal; Multiply the first frequency signal of the current signal under test by the second frequency signal to obtain the second hybrid analog signal corresponding to the current signal under test.

2. The method according to claim 1, characterized in that, The step of generating a second frequency signal based on the first frequency signal using frequency synthesis technology specifically includes: The standard current signal is tracked by an analog comparator to generate a square wave signal synchronized with the first frequency signal. The square wave signal is input to a direct frequency synthesizer, and the system clock frequency signal is generated by the internal clock multiplication function of the direct frequency synthesizer. The second frequency signal is generated based on the system clock frequency signal and the preset frequency division setting of the direct frequency synthesizer.

3. The method according to claim 2, characterized in that, After generating the second frequency signal based on the system clock frequency signal and the preset frequency division setting value of the direct frequency synthesizer, the method further includes: Obtain the difference between the first frequency signal and the second frequency signal; Determine whether the difference is equal to a preset frequency difference; If the difference is not equal to the preset frequency difference, the second frequency signal is adjusted by adjusting the preset frequency division setting value until the difference between the first frequency signal and the second frequency signal is equal to the preset frequency difference.

4. The method according to claim 1, characterized in that, The step of filtering out the sum-frequency components from the first and second mixed analog signals to obtain the first low-frequency signal and the second low-frequency signal specifically includes: The first mixed analog signal and the second mixed analog signal are converted from analog to digital, and the sum and frequency components are filtered out based on a preset sampling rate to obtain the first low-frequency signal corresponding to the standard current signal and the second low-frequency signal corresponding to the current signal under test.

5. The method according to claim 4, characterized in that, The step of performing analog-to-digital conversion on the first mixed analog signal and the second mixed analog signal, and filtering out the sum-frequency components based on a preset sampling rate to obtain the first low-frequency signal corresponding to the standard current signal and the second low-frequency signal corresponding to the current signal under test, specifically includes: Based on the trigonometric identity, the first hybrid analog signal is decomposed to obtain the first difference frequency component and the first sum frequency component. Based on the trigonometric identity, the second hybrid analog signal is decomposed to obtain the second difference frequency component and the second sum frequency component; The first mixed analog signal and the second mixed analog signal are subjected to analog-to-digital conversion to generate a first digital signal and a second digital signal; The first digital signal is downsampled to the target rate by a digital filter, the first sum frequency component of the first digital signal is filtered out, and the digital signal corresponding to the first difference frequency component is output, which is denoted as the first low frequency signal. The second digital signal is downsampled to the target rate by a digital filter, the second sum frequency component of the second digital signal is filtered out, and the digital signal corresponding to the second difference frequency component is output, which is denoted as the second low frequency signal. The digital signal includes the amplitude and phase information of the difference frequency signal.

6. The method according to claim 1, characterized in that, The step of determining the ratio difference and angle difference of the measured current signal relative to the standard current signal based on the first low-frequency signal and the second low-frequency signal specifically includes: Extract the first amplitude and first phase of the first low-frequency signal; Extract the second amplitude and second phase of the second low-frequency signal; The ratio difference is calculated based on the first amplitude and the second amplitude; The angle difference is calculated based on the first phase and the second phase.

7. A broadband current transformer testing device, characterized in that, include: The acquisition module is used to acquire a standard current signal, a test current signal from a broadband current transformer, and a first frequency signal of the standard current signal and the test current signal. The first generation module is used to generate a second frequency signal based on the first frequency signal using frequency synthesis technology, wherein the second frequency signal is equal to the difference between the first frequency signal and a preset frequency difference; The second generation module is used to generate a first mixed analog signal and a second mixed analog signal based on the standard current signal, the current signal to be measured, the first frequency signal and the second frequency signal, and to filter out the sum-frequency component from the first mixed analog signal and the second mixed analog signal to obtain a first low-frequency signal and a second low-frequency signal. The determination module is used to determine the ratio difference and angle difference of the current signal under test relative to the standard current signal based on the first low-frequency signal and the second low-frequency signal; The second generation module is specifically used for: Based on the standard current signal, the current signal under test, the first frequency signal, and the second frequency signal, a first mixed analog signal and a second mixed analog signal are obtained through analog mixing technology. The mixed analog signal includes a difference frequency component and a sum frequency component. The second generation module is further used for: Multiply the first frequency signal of the standard current signal with the second frequency signal to obtain the first hybrid analog signal corresponding to the standard current signal; Multiply the first frequency signal of the current signal to be measured with the second frequency signal to obtain the second hybrid analog signal corresponding to the current signal to be measured.

8. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the steps of the broadband current transformer testing method as described in any one of claims 1 to 6.

9. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, it implements the steps of the broadband current transformer testing method as described in any one of claims 1 to 6.

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