Method and system for synchronously measuring multidirectional dielectric loss of current transformer

Abstract

The invention provides a current transformer multidirectional dielectric loss synchronous measurement method and system, and relates to the technical field of power detection, and the method comprises the steps: building a dielectric loss detection model of a current transformer under a frequency conversion test, setting a frequency adjustment interval and a voltage value adjustment interval according to the saturation characteristics of a to-be-detected current transformer, gradually adjusting the output frequency and the output voltage value of the variable-frequency power supply, determining transfer functions under different output frequencies and output voltage values, and obtaining an initial transfer function curve; and determining a target frequency interval and a target voltage value interval based on the curve characteristics of the initial transfer function curve, and determining the dielectric loss condition of the to-be-detected current transformer based on a target transfer function corresponding to the target frequency interval and the target voltage value interval. According to the invention, the medium loss is determined by measuring the transfer function of the current transformer, the frequency and voltage value adjustment interval is set by combining the saturation characteristic of the current transformer to be measured, the measurement distortion caused by saturation is reduced, and the measurement precision is improved.

Description

Technical Field

[0001] This invention relates to the field of power detection technology, and in particular to a method and system for synchronous measurement of multi-directional dielectric loss of current transformers. Background Technology

[0002] Current transformers, as key components in power systems, are responsible for converting large currents on the high-voltage side into smaller currents on the low-voltage side, facilitating measurement and protection equipment monitoring the power grid's operational status. The performance of their internal insulation materials directly affects the transformer's reliability and service life. Dielectric loss, the energy loss caused by polarization hysteresis in the insulation material under an alternating electric field, is an important indicator of insulation performance. Over time and with changes in operating conditions, the insulation material may gradually age, leading to increased dielectric loss. This, in turn, affects the safety and stability of the current transformer and may even cause partial discharge or high-energy explosions, seriously impacting the safety of the power system.

[0003] During the operation of current transformers, early insulation defects may not immediately lead to equipment failure, but if not detected and addressed in time, they can gradually develop into serious malfunctions. Highly sensitive detection methods can identify these potential problems early, allowing for appropriate repair or replacement measures to prevent failures and ensure the safe operation of the power system. However, current dielectric loss detection methods often only focus on conditions at specific frequencies, failing to comprehensively reflect the actual insulation status of the transformer. This results in discrepancies between the obtained dielectric loss values ​​and the actual values, or even omissions. Summary of the Invention

[0004] In view of this, the present invention proposes a method and system for synchronous measurement of multi-directional dielectric loss of current transformer.

[0005] The technical solution of this invention is implemented as follows: The first aspect of this invention provides a method for synchronous measurement of multi-directional dielectric loss in a current transformer, comprising:

[0006] A dielectric loss detection model for a current transformer under frequency conversion test is established. The dielectric loss detection model includes a frequency conversion power supply and a current transformer under test. The frequency conversion power supply is used to output voltage signals of different frequencies and / or different voltage values.

[0007] Based on the saturation characteristics of the current transformer under test, a frequency adjustment range and a voltage adjustment range are set. In the frequency adjustment range, the output frequency of the frequency converter is gradually adjusted with a preset frequency step size, and the output voltage of the frequency converter is synchronously adjusted in the voltage adjustment range. The transfer function under different output frequencies and output voltage values ​​is determined, and the initial transfer function curve is obtained.

[0008] The target frequency range and target voltage range are determined based on the curve characteristics of the initial transfer function curve, and the dielectric loss of the current transformer under test is determined based on the target transfer function corresponding to the target frequency range and target voltage range; the curve characteristics include the slope change, inflection point position, and amplitude fluctuation of the curve.

[0009] Based on the above technical solutions, preferably, the establishment of the dielectric loss detection model for the current transformer under frequency conversion test further includes:

[0010] The frequency converter and the current transformer under test are shielded and grounded from the external environment, and the temperature and humidity of the environment are controlled within the expected range.

[0011] Based on the above technical solutions, preferably, the step of setting the frequency adjustment range and voltage value adjustment range according to the saturation characteristics of the current transformer under test includes:

[0012] At the rated frequency, the waveform and amplitude of the secondary current are obtained when the output voltage value is different. When the waveform of the secondary current is distorted and the amplitude error exceeds the specified value, the corresponding voltage value is determined as the critical voltage.

[0013] By plotting the critical voltage values ​​corresponding to different frequencies as curves, the saturation characteristic curves of the current transformer can be obtained.

[0014] Based on the saturation characteristic curve, determine the combination of frequency adjustment range and voltage value adjustment range.

[0015] Based on the above technical solutions, preferably, the step of gradually adjusting the output frequency of the variable frequency power supply within the frequency adjustment range with a preset frequency step size, and simultaneously adjusting the output voltage value of the variable frequency power supply within the voltage value adjustment range, determining the transfer function under different output frequencies and output voltage values, and obtaining the initial transfer function curve, includes:

[0016] Set the output frequency of the variable frequency power supply to the starting frequency and set the corresponding initial voltage value;

[0017] After the current transformer reaches a steady state, the primary and secondary currents of the current transformer are measured to obtain the current transfer function.

[0018] The starting frequency of the variable frequency power supply is gradually increased according to the preset frequency step size, while the initial voltage value is adjusted synchronously. After each adjustment, the transfer function of the current transformer after reaching a stable state is obtained until the termination frequency is reached, and multiple sets of transfer functions corresponding to the output frequency and output voltage value are obtained.

[0019] The initial transfer function curves are obtained by using spline interpolation algorithm to fit the transfer functions corresponding to multiple sets of output frequencies and output voltage values.

[0020] Based on the above technical solutions, preferably, the step of determining the target frequency range and target voltage value range based on the curve characteristics of the initial transfer function curve includes:

[0021] The linearity of the initial transfer function curve is determined using the Pearson correlation coefficient, and the frequency range and voltage range corresponding to the initial transfer function curve with linearity greater than a first preset threshold are determined as the target frequency range and target voltage range.

[0022] Based on the above technical solutions, preferably, the determination of the dielectric loss of the current transformer under test based on the target transfer function corresponding to the target frequency range and the target voltage value range includes:

[0023] Obtain the equivalent parallel resistance and equivalent capacitance of the current transformer under test;

[0024] The dielectric loss parameters are determined based on the target transfer function corresponding to the target frequency range and target voltage range, as well as the equivalent parallel resistance and the equivalent capacitance.

[0025] The dielectric loss of the current transformer under test is determined based on the mapping relationship between the dielectric loss parameter, the output frequency, and the output voltage value.

[0026] Based on the above technical solutions, preferably, the determination of dielectric loss parameters based on the target transfer function corresponding to the target frequency range and target voltage value range, the equivalent parallel resistance, and the equivalent capacitance includes determining the target transfer function H(f) based on the following formula:

[0027]

[0028] Where I1 is the primary side current, I2 is the primary side current, ω=2πf is the angular frequency, f is the output frequency of the variable frequency power supply, j is the sign of the imaginary part of the complex number, and R p For the equivalent parallel resistance, C p Equivalent capacitance;

[0029] The dielectric loss parameter tanδ satisfies: tanδ=ωR p C p .

[0030] More preferably, a second aspect of the present invention provides a multi-directional dielectric loss synchronous measurement system for a current transformer, comprising: a model establishment module, an adjustment and testing module, and a loss determination module; wherein,

[0031] The model building module is configured to build a dielectric loss detection model of a current transformer under frequency conversion test; the dielectric loss detection model includes a frequency conversion power supply and a current transformer under test, and the frequency conversion power supply is used to output voltage signals of different frequencies and / or different voltage values.

[0032] The adjustment test module is configured to set a frequency adjustment range and a voltage adjustment range according to the saturation characteristics of the current transformer under test, gradually adjust the output frequency of the frequency converter in the frequency adjustment range with a preset frequency step size, and synchronously adjust the output voltage value of the frequency converter in the voltage adjustment range, determine the transfer function under different output frequencies and output voltage values, and obtain the initial transfer function curve.

[0033] The loss determination module is configured to determine the target frequency range and the target voltage range based on the curve characteristics of the initial transfer function curve, and to determine the dielectric loss of the current transformer under test based on the target transfer function corresponding to the target frequency range and the target voltage range; the curve characteristics include the slope change, inflection point position, and amplitude fluctuation of the curve.

[0034] More preferably, a third aspect of the present invention provides an electronic device, including a processor and a memory; the memory has a stored computer program, wherein the computer program, when executed by the processor, implements the multi-directional dielectric loss synchronous measurement method for current transformers described in the first aspect.

[0035] More preferably, a fourth aspect of the present invention provides a computer storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the multi-directional dielectric loss synchronous measurement method for current transformers described in the first aspect.

[0036] The multi-directional dielectric loss synchronous measurement method and system for current transformers of the present invention have the following advantages over the prior art:

[0037] 1. By setting the frequency and voltage adjustment range based on the saturation characteristics of the current transformer under test, the measurement is ensured to be performed within the normal operating range of the current transformer, reducing measurement distortion caused by saturation and making the dielectric loss detection results closer to the true value. Combined with the curve characteristics of the initial transfer function curve, the target frequency range and target voltage range can be accurately determined, avoiding errors caused by measurement in nonlinear or unstable regions, ensuring more reliable measurement data, and thus improving the accuracy of dielectric loss detection.

[0038] 2. By gradually adjusting the output frequency and output voltage of the variable frequency power supply with a preset frequency step size, the transfer function under different frequencies and voltage values ​​can be obtained, thus obtaining a detailed transfer function curve. This helps to understand the characteristics of the current transformer under different operating conditions more comprehensively, providing a rich data foundation for subsequent determination of the target transfer function, thereby improving the accuracy of dielectric loss calculation.

[0039] 3. The target frequency range and target voltage range are determined based on the curve characteristics of the initial transfer function curve, avoiding blind measurements across the entire frequency and voltage range and significantly shortening the detection time. Determining the target frequency and target voltage ranges allows the detection process to proceed under relatively stable and linear conditions, reducing the influence of external factors on the measurement results and thus improving the reliability and stability of the detection. Attached Figure Description

[0040] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0041] Figure 1 A flowchart illustrating a method for synchronous measurement of multi-directional dielectric loss of a current transformer, provided in an embodiment of the present invention;

[0042] Figure 2 This is a schematic diagram of the equivalent circuit structure of a current transformer provided in an embodiment of the present invention;

[0043] Figure 3 This is a schematic diagram of the structure of a multi-directional dielectric loss synchronous measurement device for a current transformer provided in an embodiment of the present invention;

[0044] Figure 4 This is a schematic diagram of the structure of an electronic device provided in an embodiment of the present invention. Detailed Implementation

[0045] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0046] In some embodiments, such as Figure 1 As shown, Figure 1This is a flowchart illustrating a method for synchronous measurement of multi-directional dielectric loss in a current transformer, provided by an embodiment of the present invention. The method includes:

[0047] S110, Establish a dielectric loss detection model for a current transformer under frequency conversion test; the dielectric loss detection model includes a frequency conversion power supply and a current transformer under test, the frequency conversion power supply is used to output voltage signals of different frequencies and / or different voltage values.

[0048] In this embodiment, the frequency converter should have a wide frequency and voltage regulation range to meet the testing requirements of different types of current transformers. Furthermore, its frequency regulation accuracy should be no less than ±0.1Hz, and its voltage regulation accuracy should be no less than ±0.1% to ensure the accuracy of the output signal. During frequency and voltage regulation, the frequency converter should maintain the stability of the output signal to avoid measurement errors introduced by output signal instability. The output voltage signal waveform should be close to a sine wave to reduce the influence of harmonics on the measurement of dielectric loss of the current transformer. The frequency converter is connected to the primary winding of the current transformer under test via a high-voltage cable, applying the regulated voltage signal to the current transformer.

[0049] In some embodiments, S110, establishing a dielectric loss detection model for a current transformer under frequency conversion testing further includes:

[0050] The frequency converter and the current transformer under test are shielded and grounded from the external environment, and the temperature and humidity of the environment are controlled within the expected range.

[0051] Various electromagnetic signals exist in the external environment, such as radio broadcasts, mobile communication base station signals, and harmonics in power lines. These electromagnetic signals can enter the detection system through spatial coupling or conduction, interfering with the output signal of the frequency converter and the measurement signal of the current transformer under test. Shielding can create a closed electromagnetic protection space, blocking the entry of external electromagnetic signals; grounding can divert any potential interference signals to the ground, preventing their accumulation and amplification in the detection system. Shielding and grounding reduce stray currents and noise in the detection system, allowing the current signal in the secondary winding of the current transformer and the voltage signal across the primary winding to more accurately reflect the actual electrical parameters, significantly reducing the impact of electromagnetic interference on the detection signal, and making the measurement data more stable and reliable.

[0052] S120: Set the frequency adjustment range and voltage adjustment range according to the saturation characteristics of the current transformer under test. In the frequency adjustment range, gradually adjust the output frequency of the frequency converter with a preset frequency step size, and synchronously adjust the output voltage value of the frequency converter in the voltage adjustment range. Determine the transfer function under different output frequencies and output voltage values, and obtain the initial transfer function curve.

[0053] The saturation characteristic of a current transformer refers to the phenomenon that, after the magnetic field strength reaches a certain value, the magnetic flux density of its core no longer increases significantly with the increase of the magnetic field strength. Saturation disrupts the linear relationship between the output current and the input current of the current transformer, thus affecting the measurement results of dielectric loss.

[0054] In this embodiment, the starting frequency is higher than the lowest frequency at which the current transformer may saturate, and the ending frequency is lower than the high-frequency response limit of the current transformer to avoid the influence of high-frequency effects on the measurement. The starting voltage can be set to 50%-70% of the rated voltage of the current transformer to avoid introducing unnecessary noise at low voltages. At each frequency point, the voltage value is gradually increased, and the output current and voltage signals of the current transformer are recorded to observe the saturation characteristics of the current transformer at different frequencies and voltages.

[0055] In some embodiments, S120, setting the frequency adjustment range and voltage value adjustment range according to the saturation characteristics of the current transformer under test includes:

[0056] At the rated frequency, the waveform and amplitude of the secondary current are obtained when the output voltage value is different. When the waveform of the secondary current is distorted and the amplitude error exceeds the specified value, the corresponding voltage value is determined as the critical voltage.

[0057] By plotting the critical voltage values ​​corresponding to different frequencies as curves, the saturation characteristic curves of the current transformer can be obtained.

[0058] Based on the saturation characteristic curve, determine the combination of frequency adjustment range and voltage value adjustment range.

[0059] In this embodiment, the output frequency of the frequency converter is set to the rated frequency of the current transformer. Starting from a lower voltage value, the output voltage of the frequency converter is gradually increased, with each increase being a small voltage step. At each voltage value, a measurement system is used to collect the current waveform and amplitude on the secondary side of the current transformer. By observing the shape of the secondary side current waveform, it is determined whether distortion has occurred. The harmonic content of the waveform is analyzed using methods such as Fourier transform. When the harmonic content exceeds a certain threshold, the waveform is considered to be distorted. The error between the actual measured value and the theoretical calculated value of the secondary side current amplitude is calculated. When the error exceeds a specified value, the amplitude error is considered to exceed the specified value. When the secondary side current waveform is distorted and the amplitude error exceeds the specified value, the corresponding voltage value can be determined as the critical voltage. By repeating the above process of determining the critical voltage at different frequencies, the critical voltage values ​​corresponding to different frequencies can be obtained. By plotting these critical voltage values ​​as curves, the saturation characteristic curve of the current transformer can be obtained.

[0060] In some embodiments, S120, the output frequency of the inverter power supply is gradually adjusted in the frequency adjustment range with a preset frequency step size, and the output voltage value of the inverter power supply is synchronously adjusted in the voltage value adjustment range to determine the transfer function under different output frequencies and output voltage values, thereby obtaining an initial transfer function curve, including:

[0061] Set the output frequency of the frequency converter to the starting frequency and set the corresponding initial voltage value;

[0062] After the current transformer reaches a steady state, the primary and secondary currents of the current transformer are measured to obtain the current transfer function.

[0063] The starting frequency of the frequency converter is gradually increased according to the preset frequency step size, while the initial voltage value is adjusted synchronously. After each adjustment, the transfer function of the current transformer after reaching a stable state is obtained until the termination frequency is reached, and multiple sets of transfer functions corresponding to the output frequency and output voltage value are obtained.

[0064] The initial transfer function curves are obtained by using spline interpolation algorithm to fit the transfer functions corresponding to multiple sets of output frequencies and output voltage values.

[0065] In this embodiment, by gradually adjusting the frequency from the starting frequency to the ending frequency and simultaneously adjusting the voltage value, the possible operating frequencies and voltage ranges of the current transformer can be fully covered. This results in richer transfer function data, accurately reflecting the characteristics of the current transformer under different operating conditions and avoiding measurement errors caused by insufficient measurement points. After each frequency and voltage adjustment, considering the dynamic response process of the current transformer, measurements are taken only after the current transformer reaches a stable state. This avoids measurement errors caused by the current transformer not reaching a stable state and improves the accuracy of the transfer function measurement.

[0066] S130, the target frequency range and target voltage range are determined based on the curve characteristics of the initial transfer function curve, and the dielectric loss of the current transformer under test is determined based on the target transfer function corresponding to the target frequency range and target voltage range; the curve characteristics include the slope change, inflection point position, and amplitude fluctuation of the curve.

[0067] The initial transfer function curve reflects the characteristics of a current transformer at different frequencies and voltages. Curve features such as slope changes, inflection point locations, and amplitude fluctuations can intuitively demonstrate the operating state and performance changes of the current transformer. By analyzing these characteristics, the regions where the current transformer's operating performance is relatively stable and exhibits good linearity can be determined, namely the target frequency range and the target voltage range.

[0068] In some embodiments, S130, determining the target frequency range and the target voltage value range based on the curve characteristics of the initial transfer function curve includes;

[0069] The linearity of the initial transfer function curve is determined using the Pearson correlation coefficient, and the frequency range and voltage range corresponding to the initial transfer function curve with linearity greater than a first preset threshold are determined as the target frequency range and target voltage range.

[0070] The Pearson correlation coefficient measures the degree of linear correlation between two variables, ranging from -1 to 1. A correlation coefficient close to 1 or -1 indicates a strong linear relationship between the two variables; a correlation coefficient close to 0 indicates a weak linear relationship. In the initial transfer function curve of a current transformer, its linearity can be assessed by calculating the Pearson correlation coefficient across different frequency and voltage ranges. The intervals with linearity greater than a first preset threshold are defined as the target frequency and target voltage ranges. Current transformers operate more stably within these ranges, and their transfer functions better conform to the linear model, which is beneficial for subsequent analyses such as dielectric loss measurement.

[0071] In some embodiments, S130, determining the dielectric loss of the current transformer under test based on the target transfer function corresponding to the target frequency range and the target voltage value range includes:

[0072] Obtain the equivalent parallel resistance and equivalent capacitance of the current transformer under test;

[0073] The dielectric loss parameters are determined based on the target transfer function and equivalent parallel resistance and equivalent capacitance corresponding to the target frequency range and target voltage range.

[0074] Based on the mapping relationship between dielectric loss parameters and output frequency and output voltage, the dielectric loss of the current transformer under test is determined.

[0075] Within a certain frequency range, the frequency response characteristics of a current transformer are measured. By fitting the measurement data, the parameters of the equivalent circuit can be obtained. For example, the impedance characteristics of a current transformer can be measured using the time-domain reflection method, indirectly obtaining the equivalent parallel resistance and equivalent capacitance.

[0076] In some embodiments, S130, determining the dielectric loss parameters based on the target transfer function and equivalent parallel resistance and equivalent capacitance corresponding to the target frequency range and target voltage range includes determining the target transfer function H(f) based on the following formula:

[0077]

[0078] Where I1 is the primary side current, I2 is the primary side current, ω=2πf is the angular frequency, f is the output frequency of the variable frequency power supply, j is the sign of the imaginary part of the complex number, and R p For the equivalent parallel resistance, C p Equivalent capacitance;

[0079] The dielectric loss parameter tanδ satisfies: tanδ=ωR p C p .

[0080] In some embodiments, please refer to Figure 2 , Figure 2 This is a schematic diagram of the equivalent circuit structure of a current transformer provided in an embodiment of the present invention; wherein, i1 represents the primary high-voltage current, i2 represents the secondary low-voltage current; R2 represents the sum of the secondary winding impedance and the load impedance, L2 represents the sum of the secondary leakage inductance and the load inductance, and Z... m Characterizing the magnetizing impedance; i μ The excitation current is characterized, and the remaining resistances and capacitances are determined based on data fitting.

[0081] Based on the working principle of the current transformer, under normal conditions, the relationship between i1 and i2 satisfies:

[0082] i1N1 = i2N2;

[0083] In the formula, N1 and N2 represent the number of turns of the high-voltage and low-voltage side coils of the current transformer, respectively. Dividing both ends by i2N1 simultaneously, we get:

[0084] n is the ratio

[0085] Therefore, under normal conditions, the high-voltage side current value i1 is proportional to the low-voltage side current value i2, and the phase difference is 0.

[0086] In some embodiments, please refer to Figure 3 , Figure 3 A multi-directional dielectric loss synchronous measurement system 300 for a current transformer, provided in an embodiment of the present invention, includes: a model establishment module 310, an adjustment and testing module 320, and a loss determination module 330; wherein,

[0087] The model building module 310 is configured to build a dielectric loss detection model of a current transformer under frequency conversion test. The dielectric loss detection model includes a frequency conversion power supply and a current transformer under test. The frequency conversion power supply is used to output voltage signals of different frequencies and / or different voltage values.

[0088] The adjustment test module 320 is configured to set a frequency adjustment range and a voltage adjustment range according to the saturation characteristics of the current transformer under test. In the frequency adjustment range, the output frequency of the frequency converter is gradually adjusted with a preset frequency step size, and the output voltage value of the frequency converter is synchronously adjusted in the voltage adjustment range. The transfer function under different output frequencies and output voltage values ​​is determined, and the initial transfer function curve is obtained.

[0089] The loss determination module 330 is configured to determine the target frequency range and target voltage range based on the curve characteristics of the initial transfer function curve, and to determine the dielectric loss of the current transformer under test based on the target transfer function corresponding to the target frequency range and target voltage range; the curve characteristics include the slope change, inflection point position, and amplitude fluctuation of the curve.

[0090] In some embodiments, the model building module 310 is specifically configured as follows:

[0091] The frequency converter and the current transformer under test are shielded and grounded from the external environment, and the temperature and humidity of the environment are controlled within the expected range.

[0092] In some embodiments, the adjustment test module 320 is specifically configured as follows:

[0093] At the rated frequency, the waveform and amplitude of the secondary current are obtained when the output voltage value is different. When the waveform of the secondary current is distorted and the amplitude error exceeds the specified value, the corresponding voltage value is determined as the critical voltage.

[0094] By plotting the critical voltage values ​​corresponding to different frequencies as curves, the saturation characteristic curves of the current transformer can be obtained.

[0095] Based on the saturation characteristic curve, determine the combination of frequency adjustment range and voltage value adjustment range.

[0096] In some embodiments, the adjustment test module 320 is specifically configured as follows:

[0097] Set the output frequency of the frequency converter to the starting frequency and set the corresponding initial voltage value;

[0098] After the current transformer reaches a steady state, the primary and secondary currents of the current transformer are measured to obtain the current transfer function.

[0099] The starting frequency of the frequency converter is gradually increased according to the preset frequency step size, while the initial voltage value is adjusted synchronously. After each adjustment, the transfer function of the current transformer after reaching a stable state is obtained until the termination frequency is reached, and multiple sets of transfer functions corresponding to the output frequency and output voltage value are obtained.

[0100] The initial transfer function curves are obtained by using spline interpolation algorithm to fit the transfer functions corresponding to multiple sets of output frequencies and output voltage values.

[0101] In some embodiments, the loss determination module 330 is specifically configured as follows:

[0102] The linearity of the initial transfer function curve is determined using the Pearson correlation coefficient, and the frequency range and voltage range corresponding to the initial transfer function curve with linearity greater than a first preset threshold are determined as the target frequency range and target voltage range.

[0103] In some embodiments, the loss determination module 330 is specifically configured as follows:

[0104] Obtain the equivalent parallel resistance and equivalent capacitance of the current transformer under test;

[0105] The dielectric loss parameters are determined based on the target transfer function and equivalent parallel resistance and equivalent capacitance corresponding to the target frequency range and target voltage range.

[0106] Based on the mapping relationship between dielectric loss parameters and output frequency and output voltage, the dielectric loss of the current transformer under test is determined.

[0107] In some embodiments, the loss determination module 330 is specifically configured to determine the target transfer function H(f) based on the following formula:

[0108]

[0109] Where I1 is the primary side current, I2 is the primary side current, ω=2πf is the angular frequency, f is the output frequency of the variable frequency power supply, j is the sign of the imaginary part of the complex number, and R p For the equivalent parallel resistance, C p Equivalent capacitance;

[0110] The dielectric loss parameter tanδ satisfies: tanδ=ωR p C p .

[0111] It should be noted that the current transformer multi-directional dielectric loss synchronous measurement system provided in this application embodiment and the current transformer multi-directional dielectric loss synchronous measurement method provided in this application embodiment are based on the same application concept. Therefore, the specific implementation of this embodiment can refer to the implementation of the aforementioned current transformer multi-directional dielectric loss synchronous measurement method, and the repeated parts will not be described again.

[0112] In some embodiments, please refer to Figure 4 , Figure 4This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application. The electronic device 400 provided in this embodiment includes a processor 410 and a memory 420; the memory 420 stores a computer program, wherein the computer program, when executed by the processor, implements the aforementioned method for synchronous measurement of multi-directional dielectric losses of a current transformer.

[0113] Specifically, processor 410 may include, for example, a general-purpose microprocessor, an instruction set processor and / or an associated chipset and / or a special-purpose microprocessor (e.g., an application-specific integrated circuit (ASIC)), etc. Processor 410 may also include onboard memory for caching purposes. Processor 410 may be a single processing unit or multiple processing units for performing different actions of the method flow according to embodiments of this application.

[0114] Memory 420 may be any medium capable of containing, storing, transmitting, propagating, or transmitting instructions. For example, memory 420 may include, but is not limited to, electrical, magnetic, optical, electromagnetic, infrared, or semiconductor systems, devices, instruments, or propagation media. Specific examples of memory 420 include: magnetic storage devices such as magnetic tape or hard disk drives (HDDs); optical storage devices such as optical discs (CD-ROMs); and may also be random access memory (RAM) or flash memory; and / or wired / wireless communication links.

[0115] This application also provides a computer-readable medium storing a computer program that, when executed by a processor, implements the aforementioned method for synchronous measurement of multi-directional dielectric losses in a current transformer. This computer-readable medium may be included in the device / apparatus / system described in the above embodiments; or it may exist independently and not assembled into that device / apparatus / system. The aforementioned computer-readable medium carries one or more programs, which, when executed, implement the method according to the embodiments of this application.

[0116] According to embodiments of this application, a computer-readable medium may be a computer-readable signal medium or a computer-readable storage medium, or any combination thereof. A computer-readable storage medium may be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination thereof. More specific examples of a computer-readable storage medium may include, but are not limited to: an electrical connection having one or more wires, a portable computer disk, a hard disk, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage device, magnetic storage device, or any suitable combination thereof. In this application, a computer-readable storage medium may be any tangible medium containing or storing a program that can be used by or in conjunction with an instruction execution system, apparatus, or device. In this application, a computer-readable signal medium may include a data signal propagated in baseband or as part of a carrier wave, carrying computer-readable program code. Such propagated data signals may take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination thereof. Computer-readable signal media can also be any computer-readable medium other than computer-readable storage media, which can send, propagate, or transmit a program for use by or in connection with an instruction execution system, apparatus, or device. The program code contained on the computer-readable medium can be transmitted using any suitable medium, including but not limited to: wireless, wired, optical fiber, radio frequency signals, etc., or any suitable combination thereof.

[0117] Those skilled in the art will understand that the features described in the various embodiments and / or claims of this application can be combined and / or combined in various ways, even if such combinations or combinations are not explicitly described in this application. In particular, the features described in the various embodiments and / or claims of this application can be combined and / or combined in various ways without departing from the spirit and teachings of this application. All such combinations and / or combinations fall within the scope of this application. Therefore, the scope of this application should not be limited to the above embodiments, but should be defined not only by the appended claims, but also by their equivalents. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this invention should be included within the protection scope of this invention.

Claims

1. A method for synchronous measurement of multi-directional dielectric loss of a current transformer, characterized in that, include: Establish a dielectric loss detection model for current transformers under frequency conversion tests; The dielectric loss detection model includes a frequency converter and a current transformer under test. The frequency converter is used to output voltage signals with different frequencies and / or different voltage values. Based on the saturation characteristics of the current transformer under test, a frequency adjustment range and a voltage adjustment range are set. In the frequency adjustment range, the output frequency of the frequency converter is gradually adjusted with a preset frequency step size, and the output voltage of the frequency converter is synchronously adjusted in the voltage adjustment range. The transfer function under different output frequencies and output voltage values ​​is determined, and the initial transfer function curve is obtained. The target frequency range and target voltage range are determined based on the curve characteristics of the initial transfer function curve, and the dielectric loss of the current transformer under test is determined based on the target transfer function corresponding to the target frequency range and target voltage range; the curve characteristics include the slope change, inflection point position, and amplitude fluctuation of the curve.

2. The method for synchronous measurement of multi-directional dielectric loss of current transformer as described in claim 1, characterized in that, The establishment of the dielectric loss detection model for the current transformer under frequency conversion test also includes: The frequency converter and the current transformer under test are shielded and grounded from the external environment, and the temperature and humidity of the environment are controlled within the expected range.

3. The method for synchronous measurement of multi-directional dielectric loss of current transformer as described in claim 1, characterized in that, The step of setting the frequency adjustment range and voltage value adjustment range according to the saturation characteristics of the current transformer under test includes: At the rated frequency, the waveform and amplitude of the secondary current are obtained when the output voltage value is different. When the waveform of the secondary current is distorted and the amplitude error exceeds the specified value, the corresponding voltage value is determined as the critical voltage. By plotting the critical voltage values ​​corresponding to different frequencies as curves, the saturation characteristic curves of the current transformer can be obtained. Based on the saturation characteristic curve, determine the combination of frequency adjustment range and voltage value adjustment range.

4. The method for synchronous measurement of multi-directional dielectric loss of current transformer as described in claim 1, characterized in that, The process involves gradually adjusting the output frequency of the variable frequency power supply within the frequency adjustment range using a preset frequency step size, and simultaneously adjusting the output voltage value of the variable frequency power supply within the voltage value adjustment range. This process determines the transfer function under different output frequencies and output voltage values, resulting in an initial transfer function curve, including: Set the output frequency of the variable frequency power supply to the starting frequency and set the corresponding initial voltage value; After the current transformer reaches a steady state, the primary and secondary currents of the current transformer are measured to obtain the current transfer function. The starting frequency of the variable frequency power supply is gradually increased according to the preset frequency step size, while the initial voltage value is adjusted synchronously. After each adjustment, the transfer function of the current transformer after reaching a stable state is obtained until the termination frequency is reached, and multiple sets of transfer functions corresponding to the output frequency and output voltage value are obtained. The initial transfer function curves are obtained by using spline interpolation algorithm to fit the transfer functions corresponding to multiple sets of output frequencies and output voltage values.

5. The method for synchronous measurement of multi-directional dielectric loss of current transformer as described in claim 1, characterized in that, The determination of the target frequency range and target voltage range based on the curve characteristics of the initial transfer function curve includes: The linearity of the initial transfer function curve is determined using the Pearson correlation coefficient, and the frequency range and voltage range corresponding to the initial transfer function curve with linearity greater than a first preset threshold are determined as the target frequency range and target voltage range.

6. The method for synchronous measurement of multi-directional dielectric loss of current transformer as described in claim 1, characterized in that, The determination of the dielectric loss of the current transformer under test based on the target transfer function corresponding to the target frequency range and target voltage value range includes: Obtain the equivalent parallel resistance and equivalent capacitance of the current transformer under test; The dielectric loss parameters are determined based on the target transfer function corresponding to the target frequency range and target voltage range, as well as the equivalent parallel resistance and the equivalent capacitance. The dielectric loss of the current transformer under test is determined based on the mapping relationship between the dielectric loss parameter, the output frequency, and the output voltage value.

7. The method for synchronous measurement of multi-directional dielectric loss of current transformer as described in claim 6, characterized in that, The determination of dielectric loss parameters based on the target transfer function corresponding to the target frequency range and target voltage range, the equivalent parallel resistance, and the equivalent capacitance includes determining the target transfer function H(f) based on the following formula: Where I1 is the primary side current, I2 is the primary side current, ω=2πf is the angular frequency, f is the output frequency of the variable frequency power supply, j is the sign of the imaginary part of the complex number, and R p For the equivalent parallel resistance, C p Equivalent capacitance; The dielectric loss parameter tanδ satisfies: tanδ=ωR p C p .

8. A multi-directional dielectric loss synchronous measurement system for a current transformer, characterized in that, include: The module includes a model building module, an adjustment and testing module, and a loss determination module; among them, The model building module is configured to build a dielectric loss detection model of a current transformer under frequency conversion test; the dielectric loss detection model includes a frequency conversion power supply and a current transformer under test, and the frequency conversion power supply is used to output voltage signals of different frequencies and / or different voltage values. The adjustment test module is configured to set a frequency adjustment range and a voltage adjustment range according to the saturation characteristics of the current transformer under test, gradually adjust the output frequency of the frequency converter in the frequency adjustment range with a preset frequency step size, and synchronously adjust the output voltage value of the frequency converter in the voltage adjustment range, determine the transfer function under different output frequencies and output voltage values, and obtain the initial transfer function curve. The loss determination module is configured to determine the target frequency range and the target voltage range based on the curve characteristics of the initial transfer function curve, and to determine the dielectric loss of the current transformer under test based on the target transfer function corresponding to the target frequency range and the target voltage range; the curve characteristics include the slope change, inflection point position, and amplitude fluctuation of the curve.

9. An electronic device comprising a processor and a memory; said memory having a storage for a computer program, wherein, When the computer program is executed by the processor, it implements the method for synchronous measurement of multi-directional dielectric loss of current transformers as described in any one of claims 1 to 7.

10. A computer storage medium, characterized in that, It stores a computer program, wherein when the computer program is executed by a processor, it implements the method for synchronous measurement of multi-directional dielectric loss of current transformer as described in any one of claims 1 to 7.

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