Transformer testing system

Abstract

The application discloses a transformer testing system which is composed of a sine wave generator, a micro control unit (MCU), a Fourier transform unit and a high-frequency current acquisition module. The sine wave generator is used to generate a sine wave under the control of the MCU and input the sine wave into a transformer to be tested, so that the transformer outputs a secondary voltage waveform signal and a high-frequency discharge current signal; the Fourier transform unit is used to perform Fourier transform on the secondary voltage waveform signal to obtain a frequency domain signal; the high-frequency current acquisition module is used to perform analog amplification and A / D conversion on the high-frequency discharge current signal to obtain a detection signal; and the MCU is used to judge whether there is a flashover on the secondary of the transformer and analyze whether the detection signal indicates that there is a partial discharge in the transformer, so as to determine whether the insulation index of the transformer is qualified. It can be seen that the reliability and stability of the transformer can be determined by judging whether the flashover and the insulation parameter are qualified.

Description

TECHNICAL FIELD

[0001] The present application relates to the power grid technical field, more particularly, to a transformer testing system. BACKGROUND

[0002] In the distribution network, the transformer is an important link for realizing power transmission, and the stability and reliability of the transformer are directly related to whether the power grid can operate safely and stably. Therefore, when each transformer is put into use, the transformer needs to be detected to verify the reliability and stability of the transformer. Therefore, in the prior art, the transformer is usually subjected to a high voltage test, and whether the transformer can be put into use is determined according to the result of the high voltage test.

[0003] However, the size of the voltage cannot be set in the high voltage test process, so that the accuracy of the test result obtained by the conventional preventive test is not high, and some test results of the qualified transformer may also quickly appear faults after being put into use. SUMMARY

[0004] Therefore, the present application provides a transformer testing system for providing a more reliable transformer detection process.

[0005] In order to achieve the above purpose, the present application provides the following scheme:

[0006] A transformer testing system, comprising a sine wave generator, a micro control unit (MCU), a Fourier transform unit and a high frequency current acquisition module.

[0007] The sine wave generator is configured to generate a sine wave under the control of the MCU and input the sine wave into a transformer to be tested, so that the transformer outputs a secondary voltage waveform signal and a high frequency discharge current signal.

[0008] The Fourier transform unit is configured to perform Fourier transform on the secondary voltage waveform signal to obtain a frequency domain signal.

[0009] The high frequency current acquisition module is configured to perform analog amplification and A / D conversion on the high frequency discharge current signal to obtain a detection signal.

[0010] The MCU is configured to control the sine wave generator to generate a sine wave, analyze whether there is a high frequency component in the frequency domain signal to determine whether there is a flashover on the secondary side of the transformer, and analyze whether the detection signal indicates that the transformer has a partial discharge to determine whether the insulation index of the transformer is qualified.

[0011] Optionally, the transformer testing system further comprises a power regulation and output unit.

[0012] The power regulation and output unit is used to control the maximum output power of the sine wave output by the sine wave generator, so as to prevent overload damage.

[0013] Optionally, the test voltage output unit is further included.

[0014] The test voltage output unit is used to adjust the voltage value of the sine wave input to the transformer according to the parameters of the transformer.

[0015] Optionally, the high-frequency current acquisition module includes a high-frequency current sensor (HFCT).

[0016] The HFCT is used to acquire the current signal of the high-frequency discharge output by the transformer.

[0017] Optionally, the high-frequency current acquisition module includes an analog amplification unit.

[0018] The analog amplification unit is used to analog amplify the current signal of the high-frequency discharge acquired by the HFCT.

[0019] Optionally, the high-frequency current acquisition module includes an A / D converter.

[0020] The A / D converter is used to A / D convert the high-frequency current signal analog amplified by the analog amplification unit to obtain a detection signal.

[0021] Optionally, a partial discharge detection unit is further included.

[0022] The partial discharge detection unit is used to analyze the parameters of the transformer according to the waveform, amplitude, frequency and phase of the detection signal, and determine whether the transformer is qualified according to the parameters of the transformer.

[0023] Optionally, a touch screen is further included.

[0024] The touch screen is used to display the frequency domain signal and the detection signal.

[0025] Optionally, the MCU is connected with the sine wave generator, the Fourier transform unit and the high-frequency current acquisition unit.

[0026] It can be seen from the technical solution that the transformer testing system provided by the application is composed of a sine wave generator, a micro control unit (MCU), a Fourier transform unit and a high-frequency current acquisition module. The sine wave generator is used to generate a sine wave under the control of the MCU and input the sine wave into the transformer to be tested, so that the transformer outputs a secondary voltage waveform signal and a high-frequency discharge current signal. In this way, the sine wave input into the transformer can be controlled by the MCU, so that the testing process can be more consistent with the actual use process, and the reliability of the application can be improved. Then, the Fourier transform unit is used to perform Fourier transform on the secondary voltage waveform signal to obtain a frequency domain signal; the high-frequency current acquisition module is used to perform analog amplification and A / D conversion on the high-frequency discharge current signal to obtain a detection signal; and the MCU is used to control the sine wave generator to generate a sine wave, analyze whether there is a high-frequency component in the frequency domain signal to determine whether there is a flashover on the secondary side of the transformer, and analyze whether the detection signal indicates that the transformer has partial discharge to determine whether the insulation index of the transformer is qualified. In this way, the application can monitor whether there is a flashover on the secondary side of the transformer and whether the insulation of the transformer is qualified through the above process, further detect the condition of the transformer in use, and further monitor the reliability and stability of the transformer. It can be seen that the application can simulate the actual use condition through the sine wave generator, and further determine the reliability and stability of the transformer by judging whether the flashover and insulation parameters are qualified. BRIEF DESCRIPTION OF DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced. Obviously, the drawings in the following description are only embodiments of the application, and other drawings can be obtained by those skilled in the art without creative labor on the basis of the provided drawings.

[0028] Figure 1 A composition schematic diagram of a transformer testing system disclosed by the embodiments of the application;

[0029] Figure 2 A sine wave generation schematic diagram disclosed by the embodiments of the application;

[0030] Figure 3 A frequency domain signal schematic diagram disclosed by the embodiments of the application;

[0031] Figure 4 A detection signal schematic diagram disclosed by the embodiments of the application;

[0032] Figure 5 Another detection signal schematic diagram disclosed by the embodiments of the application;

[0033] Figure 6 Another schematic view of a transformer testing system disclosed in embodiments of the present application. DETAILED DESCRIPTION

[0034] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0035] The transformer testing system provided in the present application can be applied to test the reliability and stability of a transformer.

[0036] Next, the transformer testing system of the present application will be described in detail. Figure 1 The transformer testing system of the present application will be described in detail.

[0037] Referring to Figure 1 It can be found that the transformer testing system of the present application can be composed of a sine wave generator, a micro control unit (MCU), a Fourier transform unit and a high-frequency current acquisition module.

[0038] The sine wave generator can generate a sine wave under the control of the MCU by using a natural area algorithm. The input of the transformer is the sine wave generated by the sine wave generator.

[0039] Specifically, the natural area algorithm is an important theoretical basis of PWM control technology, that is, in sampling control, narrow pulses with equal impulse and different shapes are applied to the same element with inertia, and their effects are basically the same. The impulse refers to the area of the narrow pulse, and the basically same effect refers to the basically same output response waveform of the element. The greater the PWM pulse area, the higher the output voltage after conversion. As shown in Figure 2 The sine half wave can be regarded as a waveform composed of N pulse sequences connected to each other. The pulse width of each pulse sequence is equal to N, but the amplitude is not equal, and the top of the pulse is not a horizontal straight line, but a curve that changes according to the sine law. If these pulse sequences are replaced by the same number of rectangular pulses with equal amplitude and unequal width, the midpoint of the rectangular pulse is coincided with the midpoint of the corresponding sine wave part, and the area of the rectangular pulse is equal to the area of the corresponding sine wave part, then the rectangular pulse sequence is obtained, which is the PWM waveform obtained according to the natural area algorithm.

[0040] Thus, the area of the PWM waveform output by the MCU can be controlled to vary according to a sine rule, and the output after conversion and filtering is a standard sine wave voltage, the amplitude of the sine wave voltage being controlled by the duty cycle of the PWM signal output by the MCU. The frequency of the sine wave voltage is controlled by the variation period of the PWM signal output by the MCU. That is, the voltage amplitude and frequency of the sine wave are precisely controlled by the MCU.

[0041] The sine wave generator can be used to generate a sine wave meeting the test requirements according to the duty cycle and variation period of the PWM waveform output by the MCU, and input the sine wave into the transformer to be tested, so that the transformer outputs a secondary voltage waveform signal and a high-frequency discharge current signal.

[0042] The voltage amplitude of the sine wave generated by the sine wave generator ranges from 0V to 500V, and the frequency ranges from 40Hz to 60Hz.

[0043] After the sine wave is input into the transformer, the transformer outputs a secondary voltage waveform signal.

[0044] The Fourier transform unit can perform fast Fourier transform on the secondary voltage waveform signal output by the transformer to obtain a frequency domain signal.

[0045] The secondary voltage waveform signal can be obtained by a voltage sensor PT installed on the secondary side of the transformer, and the PT can transmit the obtained secondary voltage waveform signal to the Fourier transform unit.

[0046] The frequency domain signal can indicate each frequency domain component of the secondary voltage waveform signal, and once flashover occurs on the secondary side of the transformer, there will be a high-frequency component in the frequency domain signal in addition to the fundamental wave, such as Figure 3 .

[0047] Thus, the MCU can be used to analyze whether there is a high-frequency component in the frequency domain signal output by the Fourier transform unit, that is, whether different frequency signal components are superimposed in the frequency domain signal. When the MCU detects a high-frequency component, it indicates that flashover has occurred on the secondary side of the transformer.

[0048] In addition, after the sine wave is input into the transformer, the transformer can also output a high-frequency discharge current signal.

[0049] The high-frequency current acquisition module can be used to perform analog amplification and A / D conversion on the high-frequency discharge current signal to obtain a detection signal.

[0050] The detection signal can indicate whether there is a defect in the internal insulation of the transformer.

[0051] If there is an insulation defect inside the transformer, under the excitation of the sine wave, partial discharge will occur in the insulation defect area, and the partial discharge will cause the detection signal to have a large fluctuation, that is, there is a pulse such as Figure 4 As shown, if there is no insulation defect inside the transformer, the waveform of the detection signal is almost a straight line, and only a small amplitude noise signal exists, as shown in Figure 5 .

[0052] Therefore, the MCU can analyze whether there is a large fluctuation in the detection signal, that is, whether the detection signal indicates that the transformer has partial discharge. When there is a large fluctuation in the detection signal, that is, the detection signal indicates that the transformer has partial discharge, it indicates that the transformer has an insulation defect, and the insulation index is unqualified.

[0053] The whole transformer test system adopts an ARM controller and is combined with a 24BIT ADC to realize precise closed-loop measurement and control functions.

[0054] As can be seen from the above technical solution, in the present application, the sine wave input to the transformer can be controlled by the MCU, so that the test process can be more in line with the actual use process. At the same time, the present application can judge whether the transformer secondary exists flashover and judge whether the transformer inside exists insulation defect, more comprehensively detects each performance index of the transformer, makes the detection result of the present application more reliable, can verify the reliability and stability of the transformer from multiple angles, so as to improve the accuracy of the present application. And the transformer test system of the present application adopts closed-loop control, the measurement process is automated, which is superior to the traditional control box and harmonic voltmeter.

[0055] In some embodiments of the present application, the transformer test system of the present application further comprises a power regulation and output unit.

[0056] Referring to Figure 6 It can be found that the power regulation and output unit of the present application is connected with the sine wave generator, the sine wave generator is connected with the MCU, the output end of the high-frequency current acquisition module is connected with the MCU, and the output end of the Fourier transform unit is connected with the MCU.

[0057] The power regulation and output unit can be used to control the maximum output power of the sine wave output by the sine wave generator to prevent overload damage.

[0058] As can be seen from the above technical solution, the power regulation and output unit capable of preventing overload is added in the present application, which further better tests the transformer and improves the usable times of the transformer test system of the present application, further saving the economic expenditure of the transformer test.

[0059] In some embodiments of the present application, the transformer test system of the present application further comprises a test voltage output unit.

[0060] The test voltage output unit can be used to adjust the voltage value of the sine wave input to the transformer according to the parameters of the transformer and test requirements. The test voltage output unit can control the voltage amplitude of the sine wave output to the transformer according to the test voltage value required by the national standard.

[0061] From the above technical solution, the test voltage output unit is added, the voltage amplitude of the sine wave input to the transformer can be controlled by the test voltage output unit, and the test precision is improved.

[0062] In some embodiments of the present application, the high-frequency current acquisition module includes a high-frequency current sensor HFCT.

[0063] The HFCT can be used to acquire the current signal of the high-frequency discharge output by the transformer.

[0064] The HFCT can be connected with the output end of the transformer and connected with the input end of the analog amplification unit.

[0065] From the above technical solution, the high-frequency current acquisition module of the present embodiment can include a high-frequency current sensor, and the acquisition of the current signal of the high-frequency discharge can be better realized through the high-frequency current sensor, thereby improving the reliability of the insulation detection of the present application.

[0066] In some embodiments of the present application, the high-frequency current acquisition module can further include an analog amplification unit.

[0067] The analog amplification unit can be used to analog amplify the current signal of the high-frequency discharge acquired by the HFCT.

[0068] The analog amplification unit can be a programmable gain amplifier THS7001 with an independent preamplifier stage.

[0069] The MCU can control the gain of the THS7001 according to the amplitude of the signal output by the HFCT. The gain of the THS7001 can be changed between -22dB and +20dB by configuring the 3-bit gain control pin of the THS7001, so that the analog local amplification signal reaches the optimal linear range of the A / D converter of the single-chip microcomputer, and the highest sampling precision is achieved.

[0070] From the above technical solution, the high-frequency current acquisition module of the present embodiment can further include an analog amplification unit, and the sampling precision of the present application can be improved by the analog amplification unit, thereby improving the accuracy of the insulation detection of the present application.

[0071] In some embodiments of the present application, the high-frequency current acquisition module can include an A / D converter.

[0072] An A / D converter can be used to perform A / D conversion on the high-frequency current signal analog amplified by the analog amplification unit to obtain a detection signal.

[0073] An input end of the A / D converter can be connected with an output end of the analog amplification unit, and an output end of the A / D converter can be connected with an input end of the partial discharge detection unit.

[0074] As can be seen from the above technical solution, the high-frequency current acquisition module in the present application can include an A / D converter, and the A / D converter can be used to better determine whether the insulation index of the transformer is qualified according to the partial discharge data.

[0075] In some embodiments of the present application, the transformer test system can further include a partial discharge detection unit, which can be used to analyze parameters of the transformer according to a waveform, an amplitude, a frequency and a phase of the detection signal, and determine whether the transformer is qualified according to the parameters of the transformer.

[0076] Specifically, the insulation parameters of the transformer can be analyzed according to whether the waveform of the detection signal is similar to a straight line, an amplitude difference of the detection signal, whether the amplitudes corresponding to each frequency are similar, and the like, and when the insulation parameters are unqualified, it is determined that the transformer is unqualified.

[0077] As can be seen from the above technical solution, the partial discharge detection unit is added in the present embodiment, and the transformer can be verified to be qualified or not from multiple aspects reflected by the detection signal through the partial discharge detection unit, so as to improve the accuracy of verifying the reliability and stability of the transformer in the present application.

[0078] In some embodiments of the present application, the transformer test system can further include a touch screen, and the touch screen can be connected with the MCU.

[0079] The touch screen can be used to display the frequency domain signal and the detection signal.

[0080] The touch screen can be a graphical operation UI interface.

[0081] The MCU can analyze and filter the input frequency domain signal and detection signal, compare the partial discharge waveform library, and form quantitative data such as discharge pulse intensity, discharge frequency and discharge type, which are displayed in A / B / C three phases respectively. The values reaching the discharge early warning or alarm are displayed in different colors on the touch screen.

[0082] As can be seen from the above technical solution, the quantitative data in the present application can be directly displayed on the touch screen, without configuration and learning cost, and the data can further better display the test results of the transformer.

[0083] Finally, it should be noted that the terms "first", "second", and the like, herein do not denote any order, quantity, combination, or otherwise, but are used to identify one entity from another, and do not imply any actual relationship or sequence among entities. Also, the use of the term "including", "containing" or any other variant to refer to a list of elements to be combined is intended to denote that not only the listed elements can be present, but also other elements not expressly listed. The term "consisting of" excludes any element not named in the list of elements from the process, method, article, or apparatus. Without further limitation, an element defined by a statement "comprising a" does not exclude the presence of additional identical elements in the process, method, article, or apparatus including the stated element.

[0084] The various embodiments in the specification are described in progressive order with reference to each embodiment, each embodiment highlighting differences from other embodiments, and the same or similar parts among the various embodiments can be mutually referred to.

[0085] The above description of disclosed embodiments enables a person skilled in the art to implement or use the application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the application. The various embodiments of the application can be combined with each other. Therefore, the application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A transformer testing system, characterized by, The device comprises a sine wave generator, a micro control unit (MCU), a Fourier transform unit and a high-frequency current acquisition module. The sine wave generator is configured to generate a sine wave under the control of the MCU and input the sine wave into a transformer to be tested, so that the transformer outputs a secondary voltage waveform signal and a high-frequency discharge current signal. The Fourier transform unit is configured to perform Fourier transform on the secondary voltage waveform signal to obtain a frequency domain signal. The high-frequency current acquisition module is configured to perform analog amplification and A / D conversion on the high-frequency discharge current signal to obtain a detection signal. The MCU is configured to control the sine wave generator to generate a sine wave, analyze whether there is a high-frequency component in the frequency domain signal to determine whether there is a flashover on the secondary side of the transformer, and analyze whether the detection signal indicates that the transformer has partial discharge to determine whether the insulation index of the transformer is qualified.

2. The transformer testing system of claim 1, wherein, The device further comprises a power regulation and output unit. The power regulation and output unit is configured to control the maximum output power of the sine wave output by the sine wave generator to prevent overload damage.

3. The transformer testing system of claim 1, wherein, The device further comprises a test voltage output unit. The test voltage output unit is configured to adjust the voltage value of the sine wave input into the transformer according to the parameters of the transformer.

4. The transformer testing system of claim 1, wherein, The high-frequency current acquisition module comprises a high-frequency current sensor (HFCT). The HFCT is configured to acquire the high-frequency discharge current signal output by the transformer.

5. The transformer testing system of claim 4, wherein, The high-frequency current acquisition module further comprises an analog amplification unit. The analog amplification unit is configured to perform analog amplification on the high-frequency discharge current signal acquired by the HFCT.

6. The transformer testing system of claim 5, wherein, The high-frequency current acquisition module further comprises an A / D converter. The A / D converter is configured to perform A / D conversion on the high-frequency current signal analog amplified by the analog amplification unit to obtain a detection signal.

7. The transformer testing system of claim 1, wherein, The device further comprises a partial discharge detection unit. The partial discharge detection unit is configured to analyze the parameters of the transformer according to the waveform, amplitude, frequency and phase of the detection signal and determine whether the transformer is qualified according to the parameters of the transformer.

8. The transformer testing system of claim 1, wherein, The device further comprises a touch screen. The touch screen is configured to display the frequency domain signal and the detection signal.

9. The transformer testing system of claim 1, wherein, The MCU is connected with the sine wave generator, the Fourier transform unit and the high-frequency current acquisition module.

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