State detection method and device of distribution network transformer, processor and electronic equipment

Abstract

The invention discloses a state detection method and device for a distribution network transformer, a processor and electronic equipment. The method comprises the following steps: determining initial voltages at two ends of a to-be-tested transformer; based on the initial voltage, current signals of the to-be-detected transformer in different time periods are determined, and a plurality of current signals corresponding to the different time periods are obtained; based on the plurality of current signals corresponding to different time periods, determining frequency domain signals of the to-be-tested transformer under different frequencies, the different frequencies being in one-to-one correspondence with the different time periods; based on the frequency domain signal, the state of a coil in the transformer to be detected is detected, and the state comprises that the coil is in a normal insulation state or in an abnormal insulation state. The technical problem that the fault frequency of the transformer is high is solved.

Description

Technical Field

[0001] The present invention relates to the field of electric power, and in particular to a state detection method, device, processor and electronic equipment for a distribution network transformer. Background Art

[0002] In the application process of transformers, even if some transformers with qualified test data are used, they may fail soon. This is because traditional tests usually cannot test transformers under rated voltage conditions, making it difficult to detect defects in transformer turn-to-turn insulation, which leads to technical problems such as high frequency of transformer failures.

[0003] With respect to the technical problem of high frequency of transformer failure, no effective solution has been proposed so far. Summary of the invention

[0004] The embodiments of the present invention provide a method, device, processor and electronic device for detecting the state of a distribution network transformer, so as to at least solve the technical problem that the transformer has a high frequency of failure.

[0005] According to one aspect of an embodiment of the present invention, a state detection method for a distribution network transformer is provided, the method comprising: determining an initial voltage across both ends of a transformer to be tested; based on the initial voltage, respectively determining current signals of the transformer to be tested in different time periods to obtain a plurality of current signals corresponding to the different time periods; based on the plurality of current signals corresponding to the different time periods, determining frequency domain signals of the transformer to be tested at different frequencies, wherein different frequencies correspond one-to-one to different time periods; based on the frequency domain signals, detecting a state of a coil inside the transformer to be tested, wherein the state comprises the coil being in a normal insulation state, or the coil being in an abnormal insulation state.

[0006] Optionally, based on multiple current signals corresponding to different time periods, determining frequency domain signals of the transformer under test at different frequencies includes: respectively determining digital signals corresponding to the multiple current signals; and performing frequency domain transformation on the digital signals to obtain frequency domain signals.

[0007] Optionally, respectively determining digital signals corresponding to the plurality of current signals includes: performing digital conversion on the plurality of current signals to obtain corresponding digital signals.

[0008] Optionally, based on the frequency domain signal, detecting the state of the coil inside the transformer to be tested includes: extracting the frequency spectrum of the transformer to be tested from the frequency domain signal; and detecting the state based on the frequency spectrum.

[0009] Optionally, detecting the state based on the spectrum includes: identifying the spectrum to obtain a recognition result, wherein the recognition result is used to indicate whether the waveform of the spectrum is a sine wave; and detecting the state based on the recognition result.

[0010] Optionally, based on the recognition result, the detection state includes: in response to the recognition result indicating that the waveform is a sine wave, detecting that the coil is in a normal insulation state; in response to the recognition result indicating that the waveform is not a sine wave, detecting that the coil is not in a normal insulation state.

[0011] According to one aspect of an embodiment of the present invention, a state detection device for a distribution network transformer is provided, and the device may include: a first determination unit, used to determine the initial voltage across the two ends of the transformer to be tested; a second determination unit, used to determine the current signals of the transformer to be tested in different time periods based on the initial voltage, and obtain multiple current signals corresponding to different time periods; a third determination unit, used to determine the frequency domain signals of the transformer to be tested at different frequencies based on the multiple current signals corresponding to different time periods, wherein different frequencies correspond to different time periods one by one; a detection unit, used to detect the state of the coil inside the transformer to be tested based on the frequency domain signal, wherein the state includes the coil being in a normal insulation state, or the coil being in an abnormal insulation state.

[0012] According to another aspect of the embodiment of the present invention, a processor is further provided, wherein the processor is used to run a program, wherein when the program is run by the processor, the state detection method of the distribution network transformer in the embodiment of the present invention is executed.

[0013] According to another aspect of an embodiment of the present invention, an electronic device is further provided, including: a memory storing an executable program; and a processor for running the program, wherein when the program is running, the state detection method of the distribution network transformer in each embodiment of the present invention is executed.

[0014] According to another aspect of the present invention, a computer-readable storage medium is provided, which includes a stored program, wherein when the program is executed, the device where the computer-readable storage medium is located is controlled to execute the state detection method of the distribution network transformer in the present invention.

[0015] According to another aspect of the embodiments of the present invention, a computer program product is further provided. The computer program product includes a computer program. When the computer program is executed by a processor, the state detection method of the distribution network transformer in the embodiments of the present invention is implemented.

[0016] According to another aspect of an embodiment of the present invention, a computer program product is also provided, including a non-volatile computer-readable storage medium, wherein the non-volatile computer-readable storage medium is used to store a computer program, and when the computer program is executed by a processor, the state detection method of the distribution network transformer in the embodiment of the present invention is implemented.

[0017] According to another aspect of the embodiments of the present invention, the embodiments of the present application further provide a computer program, which, when executed by a processor, implements the state detection method of the distribution network transformer in the above-mentioned embodiments of the present invention.

[0018] In an embodiment of the present invention, when detecting the state of the distribution network transformer, the initial voltage across the two ends of the transformer to be tested can be determined. Based on the determined initial voltage, the current signals of the transformer to be tested at different time periods are determined respectively, and multiple current signals corresponding to different time periods can be obtained. Based on the multiple current signals corresponding to different time periods, the frequency domain signals of the transformer to be tested at different frequencies can be determined, and based on the determined frequency domain signals of the transformer to be tested at different frequencies, the state of the coil inside the transformer to be tested can be detected, thereby achieving the purpose of detecting defects in the insulation between turns of the transformer, thereby solving the technical problem of the high frequency of transformer failures, and further achieving the technical effect of reducing the frequency of transformer failures. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of this application. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0020] Figure 1 is a flow chart of a method for detecting the state of a distribution network transformer according to an embodiment of the present invention;

[0021] FIG2( a ) is a schematic diagram of a holographic analyzer for a distribution network transformer according to an embodiment of the present invention;

[0022] FIG2( b ) is a schematic diagram of a discharge detection circuit according to an embodiment of the present invention;

[0023] Figure 3 is a schematic diagram of a state detection device for a distribution network transformer according to an embodiment of the present invention. DETAILED DESCRIPTION

[0024] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only embodiments of a part of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0025] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0026] According to an embodiment of the present invention, a method for detecting the state of a distribution network transformer is provided. It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and although a logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0027] Figure 1 is a flow chart of a method for detecting the state of a distribution network transformer according to an embodiment of the present invention. The method may include the following steps:

[0028] Step S101, determining the initial voltage across the transformer to be tested.

[0029] In the technical solution provided in the above step S101 of the present invention, the above initial voltage can be a sinusoidal wave voltage, the size of the above initial voltage can be controlled by a microprocessor, the microprocessor can be powered by a power supply, and the above initial voltage can also be called a test voltage, which is only used as an example here without specific limitation.

[0030] In this embodiment, the transformer to be tested may also be referred to as a tested transformer, which is merely an example and not specifically limited here.

[0031] In this embodiment, the initial voltage across the transformer to be tested is determined. Optionally, this embodiment uses a microprocessor to generate a current that satisfies a sine wave, and the power corresponding to the current can be determined. According to the measurement requirements of the transformer to be tested, the determined power is adjusted, and the initial voltage across the transformer to be tested can be determined based on the adjusted power.

[0032] Step S102: based on the initial voltage, respectively determine the current signals of the transformer under test in different time periods to obtain a plurality of current signals corresponding to the different time periods.

[0033] In the technical solution provided in the above step S102 of the present invention, the above current signal may be a time domain signal that varies with time.

[0034] In this embodiment, after determining the initial voltage across the two ends of the transformer to be tested, based on the initial voltage, the current signals of the transformer to be tested in different time periods are determined respectively, and multiple current signals corresponding to different time periods are obtained. Optionally, on the basis of determining the initial voltage across the two ends of the transformer to be tested, this embodiment uses a detection device to detect the state of the transformer to be tested in different time periods, and a detection result can be obtained, wherein the detection device may include but is not limited to: a voltage sensor and a high-frequency pulse current sensor, etc., and the detection result can be used to represent the electrical data of the transformer to be tested in different time periods, and the electrical data may include but is not limited to: current signal, resistance data and heating data, etc. From the obtained detection results, the current signal of the transformer to be tested in different time periods can be extracted, that is, multiple current signals corresponding to different time periods can be obtained.

[0035] Step S103: determining frequency domain signals of the transformer to be tested at different frequencies based on a plurality of current signals corresponding to different time periods.

[0036] In the technical solution provided in step S103 of the present invention, the different frequencies and the different time periods may correspond one to one. For example, the different frequencies and the different time periods may satisfy an inverse relationship, which is only an example and not specifically limited.

[0037] In this embodiment, after the current signals of the transformer under test at different time periods are determined based on the initial voltage and multiple current signals corresponding to the different time periods are obtained, the frequency domain signals of the transformer under test at different frequencies are determined based on the multiple current signals corresponding to the different time periods. Optionally, this embodiment can determine digital signals corresponding to the multiple current signals based on the multiple current signals corresponding to the different time periods. According to the determined digital signals corresponding to the multiple current signals, the frequency domain signals of the transformer under test at different frequencies can be obtained.

[0038] Step S104: detecting the state of the coil inside the transformer to be tested based on the frequency domain signal.

[0039] In the technical solution provided in the above step S104 of the present invention, the above state may include the coil being in a normal insulation state, or the coil being in an abnormal insulation state.

[0040] In this embodiment, the normal insulation state can be used to indicate that the insulation performance of the insulation material wrapping the coil reaches the target insulation performance. The target insulation performance can be used to determine whether the insulation material wrapping the coil can insulate the coils from each other.

[0041] In this embodiment, the abnormal insulation state can be used to indicate that the insulation performance of the insulation material wrapping the coil does not reach the target insulation performance. For example, if cracks, air gaps or carbonization occur in the insulation material wrapping the coil, the insulation performance of the insulation material will be affected, thereby causing the insulation performance of the insulation material to fail to reach the target insulation performance. This is only an example and is not specifically limited.

[0042] In this embodiment, after determining the frequency domain signals of the transformer under test at different frequencies based on multiple current signals corresponding to different time periods, the state of the coil inside the transformer under test is detected based on the frequency domain signals. Optionally, this embodiment can extract the spectrum of the transformer under test from the determined frequency domain signals based on determining the frequency domain signals of the transformer under test at different frequencies. According to the waveform of the extracted spectrum, it can be detected whether the state of the coil inside the transformer under test is a normal insulation state or an abnormal insulation state.

[0043] In the above steps S101 to S104 of the present application, when detecting the state of the distribution network transformer, the initial voltage at both ends of the transformer to be tested can be determined. According to the above initial voltage, the current signals of the transformer to be tested in different time periods are determined respectively, and multiple current signals corresponding to different time periods can be obtained. According to the multiple current signals corresponding to different time periods, the frequency domain signals of the transformer to be tested at different frequencies can be determined, and according to the determined frequency domain signals of the transformer to be tested at different frequencies, the state of the coil inside the transformer to be tested can be detected, thereby achieving the purpose of detecting defects in the insulation between turns of the transformer, thereby solving the technical problem of the high frequency of transformer failures, and then achieving the technical effect of reducing the frequency of transformer failures.

[0044] The above method of this embodiment is further introduced below.

[0045] As an optional implementation method, step S103, based on multiple current signals corresponding to different time periods, determines the frequency domain signals of the transformer under test at different frequencies, including: respectively determining digital signals corresponding to the multiple current signals; performing frequency domain transformation on the digital signals to obtain frequency domain signals.

[0046] In this embodiment, the frequency domain transformation may be, but is not limited to, Fast Fourier Transform (FFT) and Discrete Fourier Transform (DFT).

[0047] In this embodiment, after the current signals of the transformer under test in different time periods are determined based on the initial voltage, and multiple current signals corresponding to the different time periods are obtained, digital signals corresponding to the multiple current signals are determined respectively. Optionally, in this embodiment, digital signals corresponding to the multiple current signals can be determined respectively on the basis of obtaining multiple current signals corresponding to different time periods.

[0048] In this embodiment, after the digital signals corresponding to the multiple current signals are respectively determined, the digital signals are transformed in the frequency domain to obtain the frequency domain signals. Optionally, on the basis of determining the digital signals corresponding to the multiple current signals, this embodiment performs FFT transformation on the determined digital signals to obtain the frequency domain signals of the transformer under test at different frequencies, or performs DFT transformation on the determined digital signals to obtain the frequency domain signals of the transformer under test at different frequencies.

[0049] As an optional implementation manner, respectively determining digital signals corresponding to the multiple current signals includes: performing digital conversion on the multiple current signals to obtain corresponding digital signals.

[0050] In this embodiment, the digital conversion may be a conversion operation performed by using an analog-to-digital (A / D) converter, wherein the A / D converter may be used to convert the current signal into a corresponding digital signal.

[0051] In this embodiment, based on the initial voltage, the current signals of the transformer under test in different time periods are determined respectively, and after obtaining multiple current signals corresponding to different time periods, the multiple current signals are digitally converted to obtain corresponding digital signals. Optionally, in this embodiment, on the basis of obtaining multiple current signals corresponding to different time periods, the obtained multiple current signals are input into an A / D converter, and the input multiple current signals are digitally converted in the A / D converter to obtain corresponding digital signals.

[0052] As an optional implementation manner, step S104, based on the frequency domain signal, detecting the state of the coil inside the transformer to be tested, includes: extracting the spectrum of the transformer to be tested from the frequency domain signal; and detecting the state based on the spectrum.

[0053] In this embodiment, after determining the frequency domain signals of the transformer under test at different frequencies based on multiple current signals corresponding to different time periods, the spectrum of the transformer under test is extracted from the frequency domain signals. Optionally, this embodiment can extract the spectrum of the transformer under test from the determined frequency domain signals based on determining the frequency domain signals of the transformer under test at different frequencies.

[0054] In this embodiment, after extracting the spectrum of the transformer to be tested from the frequency domain signal, the state is detected based on the spectrum. Optionally, this embodiment can detect the state of the coil inside the transformer to be tested according to the waveform of the extracted spectrum based on the extracted spectrum, thereby determining whether the state of the coil inside the transformer to be tested is a normal insulation state or an abnormal insulation state.

[0055] As an optional implementation manner, detecting the state based on the spectrum includes: identifying the spectrum to obtain an identification result; and detecting the state based on the identification result.

[0056] In this embodiment, the above recognition result can be used to indicate whether the waveform of the spectrum is a sine wave. For example, the above recognition result can be that the waveform of the spectrum is a sine wave, or it can be that the waveform of the spectrum is not a sine wave, which is only used as an example and is not specifically limited.

[0057] In this embodiment, after extracting the spectrum of the transformer to be tested from the frequency domain signal, the spectrum is identified to obtain an identification result. Optionally, this embodiment, based on extracting the spectrum of the transformer to be tested, performs waveform identification on the extracted spectrum to obtain an identification result, that is, it can be determined whether the waveform of the spectrum is a sine wave or not.

[0058] In this embodiment, after the spectrum is identified and the identification result is obtained, the state is detected based on the identification result. Optionally, this embodiment determines the identification result based on the identification result, and the state of the coil inside the transformer to be tested can be detected.

[0059] As an optional embodiment, based on the recognition result, the detection state includes: in response to the recognition result indicating that the waveform is a sine wave, detecting that the coil is in a normal insulation state; in response to the recognition result indicating that the waveform is not a sine wave, detecting that the coil is not in a normal insulation state.

[0060] In this embodiment, after the spectrum is identified and the identification result is obtained, in response to the identification result indicating that the waveform is a sine wave, it is detected that the coil is in a normal insulation state. Optionally, this embodiment judges the obtained identification result on the basis of the obtained identification result, and if it is judged that the obtained identification result indicates that the waveform of the spectrum is a sine wave, it is detected that the coil inside the transformer to be tested is in a normal insulation state.

[0061] In this embodiment, after the spectrum is identified and the identification result is obtained, in response to the identification result indicating that the waveform is not a sine wave, it is detected that the coil is not in a normal insulation state. Optionally, this embodiment judges the obtained identification result on the basis of the obtained identification result, and if it is judged that the obtained identification result indicates that the waveform of the spectrum is not a sine wave, it is detected that the coil inside the transformer to be tested is in an abnormal insulation state.

[0062] In an embodiment of the present invention, when detecting the state of the distribution network transformer, the initial voltage across the two ends of the transformer to be tested can be determined. Based on the determined initial voltage, the current signals of the transformer to be tested at different time periods are determined respectively, and multiple current signals corresponding to different time periods can be obtained. Based on the multiple current signals corresponding to different time periods, the frequency domain signals of the transformer to be tested at different frequencies can be determined, and based on the determined frequency domain signals of the transformer to be tested at different frequencies, the state of the coil inside the transformer to be tested can be detected, thereby achieving the purpose of detecting defects in the insulation between turns of the transformer, thereby solving the technical problem of the high frequency of transformer failures, and further achieving the technical effect of reducing the frequency of transformer failures.

[0063] The technical solution of the embodiment of the present invention is illustrated below in conjunction with preferred implementation modes.

[0064] In the application process of transformers, even if some transformers with qualified test data are used, they may fail soon. This is because traditional tests usually cannot test transformers under rated voltage conditions, making it difficult to detect defects in transformer turn-to-turn insulation, which leads to technical problems such as high frequency of transformer failures.

[0065] In order to solve the above technical problems, an embodiment of the present invention proposes a state detection method for a distribution network transformer. When detecting the state of the distribution network transformer, the initial voltage at both ends of the transformer to be tested can be determined. According to the above initial voltage, the current signals of the transformer to be tested in different time periods are determined respectively, and multiple current signals corresponding to different time periods can be obtained. According to the multiple current signals corresponding to different time periods, the frequency domain signals of the transformer to be tested at different frequencies can be determined, and according to the determined frequency domain signals of the transformer to be tested at different frequencies, the state of the coil inside the transformer to be tested can be detected, thereby achieving the purpose of detecting defects in the insulation between turns of the transformer, thereby solving the technical problem of the high frequency of transformer failures, and further achieving the technical effect of reducing the frequency of transformer failures.

[0066] In this embodiment, the state of the distribution network transformer can be detected by using the holographic analyzer of the distribution network transformer. For example, FIG2(a) is a schematic diagram of a holographic analyzer of a distribution network transformer according to an embodiment of the present invention. As shown in FIG2(a), the structure of the holographic analyzer may include: a power supply 201, a touch screen 202, a microprocessor 203, a sine wave generator 204, a power regulator 205, a transformer under test 206, a high-frequency pulse current sensor 207, an A / D converter 208, and an FFT converter 209.

[0067] In this embodiment, the power supply 201 can be used to supply power to the microprocessor 203. The microprocessor 203 can be used to control the sine wave generator 204 to generate a current that satisfies a sine wave. The sine wave generator 204 can be used to input the generated current that satisfies a sine wave into the power regulator 205. The power regulator 205 can be used to input the test voltage into the transformer under test 206. The high-frequency pulse current sensor 207 can be used to perform partial discharge detection on the transformer under test 206. The A / D converter 208 can be used to convert the current signal detected by the high-frequency pulse current sensor 207 into a digital signal. The FFT converter 209 can be used to perform frequency domain conversion on the digital signal to obtain a frequency domain signal. The microprocessor 203 can also be used to extract the frequency spectrum of the transformer under test from the obtained frequency domain signal, and detect the state of the coil inside the transformer under test according to the extracted frequency spectrum. The touch screen 202 can be used to display the detected state of the coil inside the transformer under test.

[0068] In this embodiment, it is assumed that the sampling frequency is Fs, the signal frequency is F, and the number of sampling points is N. Then the result after FFT is a complex number with N points. Each point can correspond to a frequency point. The modulus value of this point is the amplitude characteristic at this frequency value. Assuming that the peak value of the original signal is A, the modulus value of each point of the FFT result (except the DC component of the first point) is N / 2 times of A. The first point is the DC component, and its modulus value is N times the DC component. The phase of each point is the phase of the signal at this frequency. The first point represents the DC component (for example, 0Hz), and the next point after the last point N represents the sampling frequency Fs, which is divided into N equal parts by N-1 points, and the frequency of each point increases successively. For example, the frequency represented by a certain point n is: Fn = (n-1) * Fs / N. It can be seen from the above formula that the frequency that Fn can distinguish is Fs / N. If the sampling frequency Fs is 1024Hz and the number of sampling points is 1024 points, 1Hz can be distinguished. A sampling rate of 1024Hz samples 1024 points, which is exactly 1 second. That is to say, if a signal of 1 second is sampled and FFT is performed, the result can be analyzed to 1Hz. If a signal of 2 seconds is sampled and FFT is performed, the result can be analyzed to 0.5Hz. If the frequency resolution is to be improved, the number of sampling points must be increased, that is, the sampling time must be increased. Among them, the frequency resolution and sampling time are inversely proportional.

[0069] It should be noted that the next point of the last point N mentioned above does not exist. Here it is a hypothetical N+1th point. It can also be regarded as dividing the first point into two parts, and moving the other half to the end. This is only an example and is not specifically limited.

[0070] In this embodiment, the discharge detection circuit can be used to perform discharge detection on the coil inside the transformer under test. For example, FIG2(b) is a schematic diagram of a discharge detection circuit according to an embodiment of the present invention. As shown in FIG2(b), I(t) can be used to represent the local discharge pulse current flowing through the conductor under test, M can be used to represent the mutual inductance between the conductor under test and the HFCT coil, and L s Can be used to represent the self-inductance of a coil, R s Can be used to represent the equivalent resistance of the coil, C s It can be used to represent the equivalent stray capacitance of the coil, R can be used to represent the load integral resistance, u o (t) can be used to represent the output voltage signal of a high frequency pulse current sensor (High Frequency Current Transformer Sensor, abbreviated as HFCT).

[0071] For example, when the sensor parameters meet the self-integration condition, the stray capacitance C is ignored. s, the transfer function of the discharge detection circuit can be expressed as follows:

[0072]

[0073] Among them, N can be used to represent the number of turns of the coil. Therefore, within an effective frequency band that meets the self-integration condition, the transfer function of HFCT is a constant that is independent of frequency. In addition, the sensitivity of HFCT is inversely proportional to the number of turns N and proportional to the integration resistance R.

[0074] Furthermore, in fact, in the high frequency band C s The influence of C cannot be ignored. s In the case of influence, the transfer function H(S) of the discharge detection circuit can be expressed as follows:

[0075]

[0076] It should be noted that the equivalent circuit of the above-mentioned discharge detection circuit can be similar to a high-frequency small-signal parallel resonant circuit. By using the high-frequency small-signal parallel resonant circuit theory for analysis, the lower limit cutoff frequency of the current sensor can be shown in the following formula (3), and the upper limit cutoff frequency of the current sensor can be shown in the following formula (4):

[0077]

[0078] For example, the primary side of the HFCT coil can be a conductor through which the measured current flows, and the secondary side can be a multi-turn coil. When an alternating current flows through the conductor passing through the center of the coil, an alternating magnetic field is generated. The secondary coil intersects with the magnetic flux generated by the measured current, and the magnetic flux generated by the secondary side of the entire HFCT coil is proportional to the current flowing through the conductor. The changing magnetic flux generates an electromotive force, and the magnitude of the electromotive force can be proportional to the rate of change of the magnetic flux. Let the current flowing through the conductor be I(t), and the electromotive force induced on the secondary side of the coil be e(t). Based on Ampere's circuit law and Faraday's law of electromagnetic induction, the electromotive force induced on the secondary side of the coil can be determined as shown in the following formula (5):

[0079]

[0080] For example, according to the different loads of the HFCT coil, the coil can be divided into an external integral coil and a self-integral coil. The external integral coil can also be called a narrowband current sensor, which has good anti-interference ability. When an external integral coil is used, it is greatly affected by the performance of the integral circuit frequency, and the upper limit of the measurement frequency is limited. It is generally used to measure medium and low frequency currents below megahertz. The self-integral coil can also be called a broadband current sensor, which has a relatively wide detection frequency band. Since the self-integral coil directly uses an integral resistor, the frequency response is faster and it is suitable for measuring pulse current signals with short rise times.

[0081] For another example, HFCT coils can be divided into HFCT coils with magnetic cores and hollow Rogowski coils according to their different structures. Among them, hollow Rogowski coils can include flexible Rogowski coils and rigid Rogowski coils. The flexible Rogowski coil uses a completely flexible material as the coil skeleton, and the wire is evenly wound around the skeleton. When detecting partial discharge, the skeleton is bent into a closed loop so that the current-carrying conductor passes through the center of the coil. This type of coil is easy to use, but the detection accuracy and stability are low. The rigid Rogowski coil uses a rigid structure coil skeleton, which allows the winding to be evenly distributed in structure, thereby achieving the ability to improve the resistance to external magnetic field interference and improve the accuracy of detection.

[0082] In this embodiment, when detecting the state of the distribution network transformer, the initial voltage across the two ends of the transformer to be tested can be determined. According to the determined initial voltage, the current signals of the transformer to be tested in different time periods are determined respectively, and multiple current signals corresponding to different time periods can be obtained. According to the multiple current signals corresponding to different time periods, the frequency domain signals of the transformer to be tested at different frequencies can be determined, and according to the determined frequency domain signals of the transformer to be tested at different frequencies, the state of the coil inside the transformer to be tested can be detected, thereby achieving the purpose of detecting defects in the insulation between turns of the transformer, thereby solving the technical problem of high frequency of transformer failures, and further achieving the technical effect of reducing the frequency of transformer failures.

[0083] According to an embodiment of the present invention, a state detection device for a distribution network transformer is also provided. It should be noted that the state detection device for a distribution network transformer can be used to execute a state detection method for a distribution network transformer in an embodiment.

[0084] Figure 3 Schematic diagram of a state detection device for a distribution network transformer according to an embodiment of the present invention. Figure 3 As shown, the distribution network transformer state detection device 300 may include: a first determination unit 301 , a second determination unit 302 , a third determination unit 303 and a detection unit 304 .

[0085] The first determining unit 301 is used to determine the initial voltage across the transformer to be tested.

[0086] The second determining unit 302 is used to determine the current signals of the transformer under test in different time periods based on the initial voltage, and obtain multiple current signals corresponding to different time periods.

[0087] The third determining unit 303 is used to determine the frequency domain signal of the transformer under test at different frequencies based on a plurality of current signals corresponding to different time periods, wherein different frequencies correspond to different time periods one by one.

[0088] The detection unit 304 is used to detect the state of the coil inside the transformer to be tested based on the frequency domain signal, wherein the state includes whether the coil is in a normal insulation state or an abnormal insulation state.

[0089] Optionally, the third determination unit 303 may include: a determination module, configured to respectively determine digital signals corresponding to the multiple current signals; and a conversion module, configured to perform frequency domain transformation on the digital signal to obtain a frequency domain signal.

[0090] Optionally, the determination module may include: a conversion submodule, configured to perform digital conversion on a plurality of current signals to obtain corresponding digital signals.

[0091] Optionally, the detection unit 304 may include: an extraction module, used to extract the frequency spectrum of the transformer to be tested from the frequency domain signal; and a detection module, used to detect the state based on the frequency spectrum.

[0092] Optionally, the detection module may include: an identification submodule, used to identify the spectrum and obtain an identification result, wherein the identification result is used to indicate whether the waveform of the spectrum is a sine wave; and a detection submodule, used to detect the state based on the identification result.

[0093] Optionally, the detection submodule can detect the state based on the recognition result by performing the following steps: in response to the recognition result indicating that the waveform is a sine wave, detecting that the coil is in a normal insulation state; in response to the recognition result indicating that the waveform is not a sine wave, detecting that the coil is not in a normal insulation state.

[0094] In this embodiment, the first determination unit is used to determine the initial voltage across the transformer to be tested; the second determination unit is used to determine the current signals of the transformer to be tested in different time periods based on the initial voltage, and obtain multiple current signals corresponding to different time periods; the third determination unit is used to determine the frequency domain signals of the transformer to be tested at different frequencies based on the multiple current signals corresponding to different time periods, wherein different frequencies correspond to different time periods one by one; the detection unit is used to detect the state of the coil inside the transformer to be tested based on the frequency domain signal, wherein the state includes the coil being in a normal insulation state, or the coil being in an abnormal insulation state, thereby achieving the purpose of detecting defects in the insulation between turns of the transformer, thereby solving the technical problem of the high frequency of transformer failures, and further achieving the technical effect of reducing the frequency of transformer failures.

[0095] According to an embodiment of the present invention, a processor is further provided, the processor being used to run a program, wherein when the program is run by the processor, the state detection method of the distribution network transformer in the embodiment is executed.

[0096] According to an embodiment of the present invention, there is further provided an electronic device, comprising: a memory storing an executable program; and a processor for running the program, wherein the state detection method of the distribution network transformer in the embodiment is executed when the program is running.

[0097] According to another aspect of the present invention, a computer-readable storage medium is provided, wherein the computer-readable storage medium includes a stored program, wherein when the program is executed, the device where the computer-readable storage medium is located is controlled to execute the state detection method of the distribution network transformer in the embodiment.

[0098] According to an embodiment of the present invention, a computer program product is further provided. The computer program product includes a computer program. When the computer program is executed by a processor, the state detection method of the distribution network transformer in the embodiment is implemented.

[0099] According to an embodiment of the present invention, a computer program product is also provided, including a non-volatile computer-readable storage medium, the non-volatile computer-readable storage medium is used to store a computer program, and when the computer program is executed by a processor, the state detection method of the distribution network transformer in the embodiment is implemented.

[0100] According to an embodiment of the present invention, a computer program is further provided. When the computer program is executed by a processor, the state detection method of the distribution network transformer in the embodiment is implemented.

[0101] The serial numbers of the above embodiments of the present invention are only for description and do not represent the advantages or disadvantages of the embodiments.

[0102] In the above embodiments of the present invention, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0103] In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways. Among them, the device embodiments described above are only schematic. For example, the division of units can be a logical function division. There may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of units or modules, which can be electrical or other forms.

[0104] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed over multiple units. Some or all of the units may be selected according to actual needs to achieve the purpose of the present embodiment.

[0105] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0106] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the relevant technology or the whole or part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, a server or a network device, etc.) to perform all or part of the steps of the methods of each embodiment of the present invention. The aforementioned storage medium includes: U disk, read-only memory (ROM, referred to as Read-Only Memory), random access memory (RAM, referred to as Random Access Memory), mobile hard disk, magnetic disk or optical disk and other media that can store program codes.

[0107] The above are only preferred embodiments of the present invention. It should be pointed out that, for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for detecting the state of a distribution network transformer, characterized in that: include: Determine the initial voltage across the transformer to be tested; Based on the initial voltage, respectively determine the current signal of the transformer under test in different time periods to obtain a plurality of current signals corresponding to different time periods; Based on the multiple current signals corresponding to the different time periods, determining the frequency domain signals of the transformer to be tested at different frequencies, wherein the different frequencies correspond to the different time periods one by one; Based on the frequency domain signal, the state of the coil inside the transformer to be tested is detected, wherein the state includes that the coil is in a normal insulation state, or that the coil is in an abnormal insulation state.

2. The method according to claim 1, characterized in that Determining frequency domain signals of the transformer to be tested at different frequencies based on the multiple current signals corresponding to the different time periods includes: respectively determining digital signals corresponding to the plurality of current signals; Perform frequency domain transformation on the digital signal to obtain the frequency domain signal.

3. The method according to claim 2, characterized in that Respectively determining digital signals corresponding to the plurality of current signals, comprising: Digital conversion is performed on the multiple current signals to obtain the corresponding digital signals.

4. The method according to claim 1, characterized in that: Detecting the state of the coil inside the transformer to be tested based on the frequency domain signal includes: Extracting the frequency spectrum of the transformer to be tested from the frequency domain signal; Based on the frequency spectrum, the state is detected.

5. The method according to claim 4, characterized in that Based on the frequency spectrum, detecting the state includes: Identify the spectrum to obtain an identification result, wherein the identification result is used to indicate whether the waveform of the spectrum is a sine wave; Based on the recognition result, the state is detected.

6. The method according to claim 5, characterized in that Based on the recognition result, detecting the state includes: In response to the recognition result indicating that the waveform is the sine wave, detecting that the coil is in the normal insulation state; In response to the recognition result indicating that the waveform is not the sine wave, it is detected that the coil is not in the normal insulation state.

7. A state detection device for a distribution network transformer, characterized in that: include: A first determining unit, used to determine the initial voltage across the transformer to be tested; A second determining unit is used to determine the current signal of the transformer under test in different time periods based on the initial voltage, and obtain a plurality of current signals corresponding to different time periods; A third determining unit, configured to determine frequency domain signals of the transformer under test at different frequencies based on the plurality of current signals corresponding to the different time periods, wherein the different frequencies correspond to the different time periods one by one; A detection unit is used to detect the state of the coil inside the transformer to be tested based on the frequency domain signal, wherein the state includes that the coil is in a normal insulation state, or that the coil is in an abnormal insulation state.

8. A processor, characterized in that: The processor is used to run a program, wherein the program, when run by the processor, executes the state detection method of the distribution network transformer according to any one of claims 1 to 6.

9. An electronic device, characterized in that: include: A memory storing an executable program; A processor is used to run the program, wherein the program executes the state detection method of the distribution network transformer according to any one of claims 1 to 6 when running.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium includes a stored executable program, wherein when the executable program is running, the device where the storage medium is located is controlled to execute the state detection method of the distribution network transformer according to any one of claims 1 to 6.

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