Current transformer state monitoring method and system

Abstract

The invention relates to the technical field of current transformer protection, and discloses a current transformer state monitoring method and system, and the method comprises the steps: collecting an instantaneous voltage signal at an output end of a current transformer, calculating an instantaneous current, and extracting an effective value and a phase angle of the output current through fast Fourier transform; and judging whether the difference value between the input current and the output current exceeds the limit or not through the dynamic threshold value, and uploading state data to a background for monitoring. Compared with the prior art that the state of a secondary circuit of a current transformer cannot be accurately detected in real time in a complex environment, and particularly, high-reliability fault identification and protection cannot be realized under the conditions of large current fluctuation, strong environment interference and the like, the method has the advantages that the dynamic threshold and the dominant frequency component phase are extracted, so that the detection accuracy is improved; rapid fault judgment of the state of the current transformer is realized, so that the problem that the transformer is damaged or the system is unstable due to the fault of a secondary circuit is avoided, and the operation reliability and the operation and maintenance efficiency of a power system are improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of current transformer protection, and in particular relates to a current transformer state monitoring method and system. Background Art

[0002] At present, the widespread application of current transformers in power systems is crucial to the realization of current measurement, protection and control. However, the existing technology has many shortcomings in the monitoring of current transformer status. For example, the existing technology usually relies on a fixed threshold judgment method. When the operating environment of the power system is complex, such as large current fluctuations and strong environmental interference, it is impossible to accurately detect the open circuit or abnormal situation of the secondary circuit; at the same time, the existing monitoring system lacks a real-time protection mechanism for faults, and cannot effectively avoid the damage of open circuit faults to the transformer and related equipment. The existing technology cannot fully meet the needs of high precision, high reliability and real-time monitoring in complex environments. Therefore, there is an urgent need for a method and system that can still realize real-time monitoring of the current transformer status, dynamic fault judgment and reliable protection under complex conditions such as large current fluctuations and strong environmental interference, so as to improve the stability and operation and maintenance efficiency of the power system. Summary of the invention

[0003] In view of the above-mentioned technical deficiencies, the purpose of the present invention is to propose a current transformer status monitoring method, aiming to solve the technical problem that the prior art cannot accurately detect the status of the current transformer secondary circuit in real time under complex environments, especially under conditions of large current fluctuations and strong environmental interference, and cannot achieve high-reliability fault identification and protection.

[0004] In order to solve the above technical problems, the present invention adopts the following technical solution: The present invention provides a current transformer state monitoring method,

[0005] The current transformer state monitoring method comprises:

[0006] Step S10: Set a sampling resistor at the output end of the current transformer to collect the instantaneous voltage signal U on the sampling resistor. out , according to the sampling resistance and instantaneous voltage signal U out Calculate the instantaneous output current i out ;

[0007] Step S20: From the instantaneous output current i out Extract the instantaneous output current effective value I out,eff , repeatedly extract the instantaneous output current effective value I according to the preset time period out,eff And combine to get a set of instantaneous output current effective value sequence I out , use fast Fourier transform to extract the instantaneous output current effective value I out,eff Extract the phase angle φ of the main frequency component out, the formula is:

[0008]

[0009] Among them, arctan is the inverse tangent function, Imag(FFT(I out,eff )) is the imaginary part of the complex number in the fast Fourier transform result, Real(FFT(I out,eff ) is the real part of the complex number in the fast Fourier transform result;

[0010] Step S30: Obtain the current transformer transformation ratio K from the current transformer nameplate;

[0011] According to the instantaneous output current effective value sequence I out Calculate the average value of the instantaneous output current effective value

[0012] According to the current transformer ratio K and the average value of the current effective value Calculate the effective value of the input current I in,eff and phase angle φ in :

[0013]

[0014] φ in =φ out +Δφ

[0015] Where Δφ is the inherent phase shift of the current transformer, which is obtained from the current transformer nameplate;

[0016] Step S40: Setting the dynamic threshold T threshold , compare the effective value of the input current I in,eff and the average value of the output current effective value Difference ΔI, if the difference ΔI is greater than the dynamic threshold T threshold , it is determined that there is a risk of failure in the secondary circuit;

[0017] Step S50: After determining that there is a risk of failure in the secondary circuit, immediately trigger the open circuit prevention circuit switch, and close the mechanical switch in parallel with the current transformer to short-circuit the secondary circuit of the current transformer, and at the same time send the status data of the current transformer to the background in JSON format.

[0018] Preferably, in step S10, the instantaneous output current i out The calculation formula is: Among them, R s is the resistance of the sampling resistor.

[0019] Preferably, in step S10, the instantaneous voltage signal U outThe data is digitized by a 12-bit digital-to-analog converter at a sampling rate of 10kHz.

[0020] Preferably, in step S10, the output current effective value I out,eff The extraction formula is:

[0021]

[0022] Where N is the number of sampling points.

[0023] Preferably, in step S40, the dynamic threshold T threshold The calculation formula is:

[0024] T threshold =T base ·(1+α·e -βt )

[0025] Among them, T base is the basic threshold value, which is determined according to the current transformer model; α and β are environmental correction coefficients, and t is the time that has passed since the last dynamic threshold calibration.

[0026] Preferably, in step S50, a short-circuit resistor R is set in the open circuit prevention circuit. short The short-circuit resistance is based on the output voltage U out And preset safety current value I safe Sure

[0027] Preferably, in step S50, the status data includes the effective value difference and phase difference between the input and output currents, environmental parameters, the switch state of the open circuit prevention circuit, and device identification information of the current transformer.

[0028] The present invention also provides a current transformer state monitoring system comprising:

[0029] The current acquisition module is used to set a sampling resistor at the output end of the current transformer and collect the instantaneous voltage signal U on the sampling resistor. out , according to the sampling resistance and instantaneous voltage signal U out Calculate the instantaneous output current i out ;

[0030] Signal processing module, used to output the instantaneous current i out Extract the instantaneous output current effective value I out,eff , repeatedly extract the instantaneous output current effective value I according to the preset time period out,eff And combine to get a set of instantaneous output current effective value sequence I out , use fast Fourier transform to extract the instantaneous output current effective value I out,eff Extract the phase angle φ of the main frequency component fromout , the formula is:

[0031]

[0032] Among them, arctan is the inverse tangent function, Imag(FFT(I out,eff )) is the imaginary part of the complex number in the fast Fourier transform result, Real(FFT(I out,eff ) is the real part of the complex number in the fast Fourier transform result;

[0033] An input calculation module is used to obtain the current transformer ratio K from the current transformer nameplate;

[0034] According to the instantaneous output current effective value sequence I out Calculate the average value of the instantaneous output current effective value

[0035] According to the current transformer ratio K and the average value of the current effective value Calculate the effective value of the input current I in,eff and phase angle φ in :

[0036]

[0037] φ in =φ out +Δφ

[0038] Where Δφ is the inherent phase shift of the current transformer, which is obtained from the current transformer nameplate;

[0039] Risk judgment module, used to set dynamic threshold T threshold , compare the effective value of the input current I in,eff and the average value of the output current effective value Difference ΔI, if the difference ΔI is greater than the dynamic threshold T threshold , it is determined that there is a risk of failure in the secondary circuit;

[0040] The protection trigger module is used to immediately trigger the open circuit prevention circuit switch after determining that there is a risk of failure in the secondary circuit, and close the mechanical switch in parallel with the current transformer to short-circuit the secondary circuit of the current transformer, and at the same time send the status data of the current transformer to the background in JSON format.

[0041] The present invention also provides a current transformer state monitoring device, comprising a memory, a processor and a current transformer state monitoring program stored in the memory and executable on the processor, wherein the current transformer state monitoring program implements the current transformer state monitoring method when executed by the processor.

[0042] The present invention also provides a computer program product, comprising a current transformer state monitoring program, wherein the current transformer state monitoring program implements the current transformer state monitoring method when executed by a processor.

[0043] The beneficial effect of the present invention is that compared with the prior art which is unable to accurately detect the secondary circuit state of the current transformer in real time under complex environments, especially under conditions such as large current fluctuations and strong environmental interference, and is unable to achieve the technical problem of high-reliability fault identification and protection, the present application realizes rapid fault judgment of the current transformer state through dynamic threshold and main frequency component phase extraction, thereby avoiding the problem of transformer damage or system instability caused by secondary circuit faults, and improving the reliability and operation efficiency of the power system. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0045] Figure 1 The figure is a flow chart of a first embodiment of a method for monitoring the state of a current transformer according to the present invention.

[0046] Figure 2 The present invention is a schematic diagram of a device for monitoring the state of a current transformer. DETAILED DESCRIPTION

[0047] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0048] Embodiment 1: Figure 1 , which is a flow chart of a first embodiment of a method for monitoring a state of a current transformer according to the present invention, provides a first embodiment of a method for monitoring a state of a current transformer according to the present invention.

[0049] In a first embodiment, the current transformer state monitoring method includes:

[0050] Step S10: Set a sampling resistor at the output end of the current transformer to collect the instantaneous voltage signal U on the sampling resistor. out , according to the sampling resistance and instantaneous voltage signal U outCalculate the instantaneous output current i out ;

[0051] It should be noted that the resistance of the sampling resistor should be small enough to avoid causing a significant burden on the secondary circuit, while meeting the accuracy requirements of the measurement range. It is usually between 0.1Ω and 1Ω. The temperature coefficient of the sampling resistor needs to be low to ensure that the output current value error is controlled within 0.1% under different working environments.

[0052] It can be understood that the instantaneous voltage signal is the real-time voltage value obtained from both ends of the sampling resistor, which is digitized by a high-resolution analog-to-digital converter. The sampling frequency is generally set to 10kHz or higher to ensure that the fine characteristics of the 50Hz industrial frequency signal can be restored. The instantaneous output current can be accurately calculated by combining the measured instantaneous voltage signal with the resistance value of the sampling resistor.

[0053] It should be understood that by collecting current signals in real time through sampling resistors, digital processing of current signals can be achieved efficiently and at low cost. At the same time, combined with high-frequency sampling and precise calculation, the dynamic change characteristics of the current can be quickly restored, providing accurate data for subsequent effective value calculations and frequency analysis.

[0054] Step S20: From the instantaneous output current i out Extract the instantaneous output current effective value I out,eff , repeatedly extract the instantaneous output current effective value I according to the preset time period out,eff And combine to get a set of instantaneous output current effective value sequence I out , use fast Fourier transform to extract the instantaneous output current effective value I out,eff Extract the phase angle φ of the main frequency component out , the formula is:

[0055]

[0056] Among them, arctan is the inverse tangent function, Imag(FFT(I out,eff )) is the imaginary part of the complex number in the fast Fourier transform result, Real(FFT(I out,eff ) is the real part of the complex part in the fast Fourier transform result;

[0057] It should be noted that the output current effective value I out,eff The extraction formula is:

[0058]

[0059] Among them, N is the number of sampling points, and the sampling frequency is generally 10kHz. The use of fast Fourier transform (FFT) can efficiently extract the main frequency component of the signal to obtain the phase angle. This process has significant advantages in high-frequency accuracy and fast response.

[0060] It is understandable that the purpose of extracting the phase angle of the main frequency component is to further determine the phase characteristics of the current transformer output signal. By calculating the phase of the main frequency component, the phase relationship between the current signal and the reference signal can be effectively reflected, which helps to accurately monitor the dynamic characteristics of the current.

[0061] It should be understood that the fast Fourier transform result provides complete component information of the current signal in the frequency domain, among which the main frequency component is the core feature of the signal. By extracting the phase angle of the main frequency, harmonic and noise interference can be eliminated and the monitoring accuracy can be improved. At the same time, the inverse tangent function converts the ratio of the imaginary part and the real part into an angle in the complex plane, ensuring the scientificity and accuracy of the phase calculation.

[0062] For example, assuming the instantaneous output current i out (t) is a power frequency sinusoidal signal, and the formula is:

[0063] i out (t) = 5sin(2π·50t+π / 6), and the instantaneous output current effective value I is obtained by RMS calculation. out,eff =5A, the signal is subjected to fast Fourier transform, and the fast Fourier transform result of the main frequency component is: Fast Fourier transform (i out (t))=5e jπ / 6 , where the imaginary part Imag(FFT(I out ))=2.5,real partReal(FFT(I out ))=4.33. The phase angle is calculated by the formula:

[0064]

[0065] It can be concluded that the phase angle of the main frequency component is 30°. This phase information can be further used for comparative analysis and fault diagnosis of the input and output signals of the current transformer, reflecting the technical effect of high-precision phase detection.

[0066] Step S30: Obtain the current transformer transformation ratio K from the current transformer nameplate;

[0067] According to the instantaneous output current effective value sequence I out Calculate the average value of the instantaneous output current effective value

[0068] According to the current transformer ratio K and the average value of the current effective value Calculate the effective value of the input current I in,eff and phase angle φ in :

[0069]

[0070] φ in =φ out +Δφ

[0071] Where Δφ is the inherent phase shift of the current transformer, which is obtained from the current transformer nameplate;

[0072] It should be noted that the transformation ratio K of the current transformer is a rated parameter determined by the transformer design and is usually marked on the transformer nameplate. For example, K = 100:1 means that the ratio of the primary current to the secondary current is 100:1. In the measurement process, accurately obtaining and applying this parameter can effectively ensure the calculation accuracy of the input current. At the same time, the average value of the instantaneous output current effective value is calculated by the mean of the sampling points. The formula is:

[0073]

[0074] Among them, N is the number of sampling points. In addition, the phase offset Δφ is an inherent characteristic parameter of the current transformer, which is caused by the hysteresis loss and inductance characteristics of the core. It is generally a fixed value in a small range, such as 1°. The specific value is marked on the nameplate or obtained through calibration testing.

[0075] It is understandable that by introducing the transformation ratio K, the secondary current can be directly converted to the primary current. This conversion method ensures the practicality and simplicity of the system. The calculation of the phase angle takes into account the inherent phase offset of the current transformer, which is due to the fact that the secondary current signal has a certain delay compared to the primary current signal. When calculating the phase angle of the input current, this part of the offset is added to accurately reflect the actual phase of the primary current.

[0076] Step S40: Setting the dynamic threshold T threshold , compare the effective value of the input current I in,eff and the average value of the output current effective value Difference ΔI, if the difference ΔI is greater than the dynamic threshold T threshold , it is determined that there is a risk of failure in the secondary circuit;

[0077] It should be noted that the setting of the dynamic threshold is to improve the sensitivity and adaptability of the current transformer secondary circuit state judgment. Different from the traditional fixed threshold method, the dynamic threshold is adjusted in real time according to environmental changes and operating status, and can accurately identify abnormal situations under complex conditions. The dynamic threshold T threshold The calculation formula is:

[0078] T threshold =T base ·(1+α·e -βt )

[0079] Among them, T base is the basic threshold value, which is determined according to the current transformer model; α and β are environmental correction coefficients, and t is the time elapsed since the last dynamic threshold calibration;

[0080] Through this formula, the dynamic threshold can be adjusted as time and external conditions change, thereby avoiding misjudgment and missed judgment.

[0081] It can be understood that by comparing the difference between the effective values ​​of the input current and the output current, abnormal conditions in the secondary circuit can be quickly identified. Significant deviations in the effective values ​​of the input and output currents usually indicate that there may be open circuits, short circuits or other fault risks in the secondary circuit. The introduction of dynamic thresholds effectively improves the robustness of fault judgment, especially in environments with large current fluctuations or electromagnetic interference, which can significantly reduce system false alarms.

[0082] Step S50: After determining that there is a risk of failure in the secondary circuit, immediately trigger the open circuit prevention circuit switch, and close the mechanical switch in parallel with the current transformer to short-circuit the secondary circuit of the current transformer, and at the same time send the status data of the current transformer to the background in JSON format.

[0083] It should be noted that the core purpose of this step is to quickly protect the current transformer and its connected equipment through the linkage action of the open-circuit prevention circuit and the mechanical switch when a fault occurs in the secondary circuit, so as to prevent damage to the equipment caused by excessive secondary voltage. This protection mechanism significantly improves the fault handling efficiency through automated response. At the same time, the system will record the transformer status data in real time and upload it to the background to facilitate remote monitoring and subsequent analysis by operation and maintenance personnel.

[0084] It is understandable that when the secondary circuit is open, the output voltage of the current transformer will rise rapidly, which may cause insulation breakdown or equipment damage. The open circuit prevention circuit is triggered immediately after the fault is determined, and the secondary circuit of the transformer is short-circuited by short-circuiting the mechanical switch, thereby limiting the further increase of voltage and ensuring system safety. At the same time, by sending the status data to the background in JSON format, the fault location, time and status can be accurately recorded, which improves the efficiency of troubleshooting.

[0085] It should be understood that the design of the open circuit prevention circuit combines the high reliability of the mechanical switch and the high sensitivity of the control unit, which can complete the short circuit protection action at the millisecond level, minimizing the impact on the equipment. In addition, the JSON format structured storage of status data facilitates system integration and remote operation, improving operation and maintenance efficiency.

[0086] In addition, a current transformer state monitoring system provided by the present invention adopts a current transformer state monitoring method in the above embodiment, which can solve a technical problem of current transformer state monitoring. Compared with the prior art, the beneficial effects of a current transformer state monitoring system provided by the present invention are the same as the beneficial effects of a current transformer state monitoring method provided by the above embodiment, and other technical features in the current transformer state monitoring system are the same as the features disclosed in the above embodiment method, which will not be repeated here.

[0087] The present invention provides a current transformer state monitoring device, please refer to Figure 2, a current transformer state monitoring device includes: at least one processor; and a memory connected to the at least one processor in communication; wherein the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor so that the at least one processor can execute a current transformer state monitoring method in the above-mentioned embodiment 1. A current transformer state monitoring device in the embodiment of the present invention may include but is not limited to mobile terminals such as mobile phones, laptop computers, digital broadcast receivers, PDAs (Personal Digital Assistants), PADs (Portable Application Descriptions), PMPs (Portable Media Players), vehicle-mounted terminals (such as vehicle-mounted navigation terminals), etc., and fixed terminals such as digital TVs, desktop computers, etc. A current transformer state monitoring device is only an example and should not bring any limitation to the functions and scope of use of the embodiments of the present invention. A current transformer state monitoring device may include a processing device 1001 (e.g., a central processing unit, a graphics processing unit, etc.), which can perform various appropriate actions and processes according to a program stored in a read-only memory (ROM) 1002 or a program loaded from a storage device 1003 to a random access memory (RAM) 1004. Various programs and data required for the operation of a current transformer state monitoring device are also stored in the RAM 1004. The processing device 1001, the ROM 1002, and the RAM 1004 are connected to each other via a bus 1005. An input / output (I / O) interface 1006 is also connected to the bus. Typically, the following systems can be connected to the I / O interface 1006: input devices 1007 including, for example, a touch screen, a touchpad, a keyboard, a mouse, an image sensor, a microphone, an accelerometer, a gyroscope, etc.; output devices 1008 including, for example, a liquid crystal display (LCD), a speaker, a vibrator, etc.; storage devices 1003 including, for example, a magnetic tape, a hard disk, etc.; and communication devices 1009. The communication device 1009 can allow a current transformer state monitoring device to communicate wirelessly or wired with other devices to exchange data. Although a current transformer state monitoring device with various systems is shown in the figure, it should be understood that it is not required to implement or have all the systems shown. More or fewer systems may be implemented or have alternatively.

[0088] The present invention also provides a computer program product, including a computer program, wherein when the computer program is executed by a processor, the steps of a current transformer state monitoring method as described above are implemented. The computer program product provided by the present invention can solve a technical problem of current transformer state monitoring. Compared with the prior art, the beneficial effects of the computer program product provided by the present invention are the same as the beneficial effects of a current transformer state monitoring method provided by the above embodiment, and will not be described in detail here.

[0089] In particular, according to the embodiments disclosed in the present invention, the process described above with reference to the flowchart can be implemented as a computer software program. For example, the embodiments disclosed in the present invention include a computer program product, which includes a computer program carried on a computer-readable medium, and the computer program contains program code for executing the method shown in the flowchart. In such an embodiment, the computer program can be downloaded and installed from the network through a communication device, or installed from the storage device 1003, or installed from the ROM 1002. When the computer program is executed by the processing device 1001, the above-mentioned functions defined in the method of the embodiment disclosed in the present invention are executed.

[0090] It should be understood that the various parts disclosed in the present invention can be implemented by hardware, software, firmware or a combination thereof. In the description of the above embodiments, specific features, structures, materials or characteristics can be combined in any one or more embodiments or examples in a suitable manner.

[0091] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A current transformer state monitoring method, characterized in that: Methods include: Step S10: Set a sampling resistor at the output end of the current transformer to collect the instantaneous voltage signal U on the sampling resistor. out , according to the sampling resistance and instantaneous voltage signal U out Calculate the instantaneous output current i out ; Step S20: From the instantaneous output current i out Extract the instantaneous output current effective value I out,eff , repeatedly extract the instantaneous output current effective value I according to the preset time period out,eff And combine to get a set of instantaneous output current effective value sequence I out , use fast Fourier transform to extract the instantaneous output current effective value I out,eff Extract the phase angle φ of the main frequency component from out , the formula is: Among them, arctan is the inverse tangent function, Imag(FFT(I out,eff )) is the imaginary part of the complex number in the fast Fourier transform result, Real(FFT(I out,eff ) is the real part of the complex part in the fast Fourier transform result; Step S30: Obtain the current transformer transformation ratio K from the current transformer nameplate; According to the instantaneous output current effective value sequence I out Calculate the average value of the instantaneous output current effective value According to the current transformer ratio K and the average value of the current effective value Calculate the effective value of the input current I in,eff and phase angle φ in : f in =φ out +Df Where Δφ is the inherent phase shift of the current transformer, which is obtained from the current transformer nameplate; Step S40: Setting the dynamic threshold T threshold , compare the effective value of the input current I in,eff and the average value of the output current effective value Difference ΔI, if the difference ΔI is greater than the dynamic threshold T threshold , it is determined that there is a risk of failure in the secondary circuit; Step S50: After determining that there is a risk of failure in the secondary circuit, immediately trigger the open circuit prevention circuit switch, and close the mechanical switch in parallel with the current transformer to short-circuit the secondary circuit of the current transformer, and at the same time send the status data of the current transformer to the background in JSON format.

2. A current transformer state monitoring method according to claim 1, characterized in that: In step S10, the instantaneous output current i out The calculation formula is: Among them, R s is the resistance of the sampling resistor.

3. A current transformer state monitoring method as claimed in claim 1, characterized in that: In step S10, the instantaneous voltage signal U out The data is digitized by a 12-bit digital-to-analog converter at a sampling rate of 10kHz.

4. A current transformer state monitoring method as claimed in claim 1, characterized in that: In step S10, the output current effective value I out,eff The extraction formula is: Where N is the number of sampling points.

5. A current transformer state monitoring method as claimed in claim 1, characterized in that: In step S40, the dynamic threshold T threshold The calculation formula is: T threshold =T base ·(1+α·e -βt ) Among them, T base is the basic threshold value, which is determined according to the current transformer model; α and β are environmental correction coefficients, and t is the time that has passed since the last dynamic threshold calibration.

6. A current transformer state monitoring method according to claim 1, characterized in that: In step S50, a short-circuit resistor R is set in the open circuit prevention circuit. short The short-circuit resistance is determined by the instantaneous voltage signal U out And preset safety current value I safe Sure 7. A current transformer state monitoring method according to claim 1, characterized in that: In step S50, the status data includes the effective value difference and phase difference between the input and output currents, environmental parameters, the switch status of the open circuit prevention circuit, and the device identification information of the current transformer.

8. A current transformer status monitoring system, characterized in that: The current transformer state monitoring system comprises: The current acquisition module is used to set a sampling resistor at the output end of the current transformer and collect the instantaneous voltage signal U on the sampling resistor. out , according to the sampling resistance and instantaneous voltage signal U out Calculate the instantaneous output current i out ; Signal processing module, used to output the instantaneous current i out Extract the instantaneous output current effective value I out,eff , repeatedly extract the instantaneous output current effective value I according to the preset time period out,eff And combine to get a set of instantaneous output current effective value sequence I out , use fast Fourier transform to extract the instantaneous output current effective value I out,eff Extract the phase angle φ of the main frequency component from out , the formula is: Among them, arctan is the inverse tangent function, Imag(FFT(I out,eff )) is the imaginary part of the complex number in the fast Fourier transform result, Real(FFT(I out,eff ) is the real part of the complex part in the fast Fourier transform result; An input calculation module is used to obtain the current transformer ratio K from the current transformer nameplate; According to the instantaneous output current effective value sequence I out Calculate the average value of the instantaneous output current effective value According to the current transformer ratio K and the average value of the current effective value Calculate the effective value of the input current I in,eff and phase angle φ in : f in =φ out +Df Where Δφ is the inherent phase shift of the current transformer, which is obtained from the current transformer nameplate; Risk judgment module, used to set dynamic threshold T threshold , compare the effective value of the input current I in,eff and the average value of the output current effective value Difference ΔI, if the difference ΔI is greater than the dynamic threshold T threshold , it is determined that there is a risk of failure in the secondary circuit; The protection trigger module is used to immediately trigger the open circuit prevention circuit switch after determining that there is a risk of failure in the secondary circuit, and close the mechanical switch in parallel with the current transformer to short-circuit the secondary circuit of the current transformer, and at the same time send the status data of the current transformer to the background in JSON format.

9. A current transformer status monitoring device, characterized in that: The current transformer state monitoring device comprises: a memory, a processor, and a current transformer state monitoring program stored in the memory and executable on the processor. When the current transformer state monitoring program is executed by the processor, the current transformer state monitoring method described in any one of claims 1 to 7 is implemented.

10. A computer program product, characterized in that The computer program product comprises a current transformer state monitoring program, and when the current transformer state monitoring program is executed by a processor, the current transformer state monitoring method described in any one of claims 1 to 7 is implemented.

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