A transformer coil longitudinal equivalent capacitance measuring device and method

Abstract

The application provides a transformer coil longitudinal equivalent capacitance measuring device and method, wherein the device comprises an oscilloscope, a pulse signal generator, an adjustable capacitance box and an isolated power supply installed in a box, the pulse signal generator is connected with the adjustable capacitance box, the oscilloscope is connected with the adjustable capacitance box, and the isolated power supply provides power supply for the oscilloscope and the pulse signal generator; the pulse signal generator outputs a voltage with a certain waveform to the measured coil and the adjustable capacitance box, the capacitance of the adjustable capacitance box is adjusted, the voltage value of the capacitance of the adjustable capacitance box is equal to the voltage value of the measured coil, and at this time, the capacitance of the capacitance box is equal to the longitudinal equivalent capacitance of the measured coil. The scheme provided by the application realizes the measurement of the longitudinal equivalent capacitance of the transformer coil through a very simple way, solves the problem that the energy equivalent method under a steep wave cannot be calculated, realizes the connection of the transformer coil through the device, avoids the problem of temporarily establishing a test loop, and simplifies the measurement work flow.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of transformer test, and particularly relates to a transformer coil longitudinal equivalent capacitance measuring device and method. BACKGROUND

[0002] The transformer in operation will encounter lightning overvoltage, and under the action of lightning overvoltage, voltage distribution in the transformer coil occurs, and the most relevant time-varying transformer coil capacitance distribution. The capacitance distribution can be simulated by design, and also needs to be compared with the actual value and the design value, and the coil initial voltage distribution under the action of steep wave impulse voltage is improved through the measured value. In the existing calculation method, the energy equivalent method is generally used for calculation, but when the wave front time of the invading lightning wave is short, the magnetizing current cannot be established within the wave front time, so the equivalent capacitance cannot be calculated by this method, and therefore it is necessary to develop a transformer coil longitudinal equivalent capacitance measuring method. At present, there is no mature special test device for such measurement research, and therefore it is necessary to design and develop a special test device and measuring method. SUMMARY

[0003] To solve the above technical problems, the present application provides a technical scheme of a transformer coil longitudinal equivalent capacitance measuring device and method to solve the above technical problems.

[0004] The first aspect of the present application discloses a transformer coil longitudinal equivalent capacitance measuring device, which comprises:

[0005] An oscilloscope, a pulse signal generator, an adjustable capacitance box, an isolation power supply and a box body;

[0006] The oscilloscope, the pulse signal generator, the adjustable capacitance box and the isolation power supply are installed in the box body, the pulse signal generator is connected with the adjustable capacitance box, the oscilloscope is connected with the adjustable capacitance box, and the isolation power supply provides power supply for the oscilloscope and the pulse signal generator;

[0007] The pulse signal generator outputs a voltage of a certain waveform to the measured coil and the adjustable capacitance box, the capacitance of the adjustable capacitance box is adjusted, so that the voltage value of the capacitance of the adjustable capacitance box is equal to the voltage value of the measured coil, at this time, the capacitance of the capacitance box is equal to the longitudinal equivalent capacitance of the measured coil.

[0008] According to the technical scheme of the first aspect of the present application, the device further comprises:

[0009] A capacitance box voltage measurement terminal, a pulse signal output terminal and a measurement line;

[0010] The capacitance box voltage measurement terminal and the pulse signal output terminal are arranged on the box body.

[0011] The oscilloscope is connected with the adjustable capacitor box through the capacitor box voltage measurement post;

[0012] One end of the measuring line is connected with the pulse signal output post, and the other end of the measuring line is connected with the measured coil.

[0013] According to the technical scheme of the first aspect of the application, the device further comprises a pulse signal waveform measurement post;

[0014] The pulse signal waveform measurement post is arranged on the box body;

[0015] The first channel of the oscilloscope is connected with the pulse signal waveform measurement post;

[0016] The second channel of the oscilloscope is connected with the adjustable capacitor box through the capacitor box voltage measurement post.

[0017] According to the technical scheme of the first aspect of the application, the device further comprises:

[0018] Universal wheels and handrails;

[0019] The universal wheels and handrails are mounted on the box body.

[0020] According to the technical scheme of the first aspect of the application, the specific structure that the isolation power supply provides power supply for the oscilloscope and the pulse signal generator comprises:

[0021] The box body is provided with main grounding and power supply, and the isolation power supply provides power supply and protection grounding for the oscilloscope and the pulse signal generator, and provides protection grounding for the adjustable capacitor box.

[0022] According to the technical scheme of the first aspect of the application, the pulse signal generator can perform waveform adjustment and output 0-400V continuous adjustable voltage suitable for various types of coils.

[0023] The second aspect of the application discloses a transformer coil longitudinal equivalent capacitance measurement method, and the method of the second aspect is applied to the device of any one of the first aspect, and the method comprises:

[0024] Step S1, the adjustable capacitor box is zeroed, the box body is grounded, and the pulse signal generator is connected with the adjustable capacitor box;

[0025] Step S2, the first channel of the oscilloscope is connected with the pulse signal waveform measurement post;

[0026] Step S3, the second channel of the oscilloscope is connected with the adjustable capacitor box through the capacitor box voltage measurement post.

[0027] Step S4, connecting one end of the measuring line to the pulse signal output terminal, and connecting the other end of the measuring line to the measured coil;

[0028] Step S5, adjusting the pulse signal generator to output a certain waveform;

[0029] Step S6, adjusting the capacitance of the adjustable capacitor box to make the voltage value of the capacitance of the adjustable capacitor box equal to the voltage value of the measured coil, at this time, the capacitance of the capacitor box is equal to the longitudinal equivalent capacitance of the measured coil.

[0030] According to the technical scheme of the second aspect of the application, the certain waveform is a measurement lightning impulse waveform with steep front time.

[0031] According to the technical scheme of the second aspect of the application, the measurement lightning impulse waveform with steep front time specifically requires that:

[0032] The front of the measurement lightning impulse waveform requires 0.9 μs ± 10%, the tail time of the measurement lightning impulse waveform is 50 μs ± 20%, and the output voltage of the measurement lightning impulse waveform is 100 V.

[0033] According to the technical scheme of the second aspect of the application, the adjustment of the capacitance of the adjustable capacitor box to make the voltage value of the capacitance of the adjustable capacitor box equal to the voltage value of the measured coil specifically includes:

[0034] Adjusting the capacitance of the adjustable capacitor box to make the voltage value of the capacitance of the adjustable capacitor box equal to 50 V, at this time, the capacitance of the capacitor box is equal to the longitudinal equivalent capacitance of the measured coil.

[0035] It can be seen that the scheme provided by the application,

[0036] 1. The measurement of the longitudinal equivalent capacitance of the transformer coil can be completed in a very simple way, and the problem that the energy equivalent method under steep wave cannot be calculated is solved.

[0037] 2. The problem of temporarily assembling a test loop is avoided by connecting the transformer coil to the device, and the measurement work flow is simplified.

[0038] 3. The measurement can be completed by outputting a low voltage signal from the pulse signal generator, and the power supply problem of the measurement is solved. BRIEF DESCRIPTION OF DRAWINGS

[0039] In order to more clearly illustrate the technical solutions in the specific embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the specific embodiments or prior art description. Obviously, the drawings described below are some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without any creative effort on the basis of these drawings.

[0040] Figure 1 A structural schematic diagram of a transformer coil longitudinal equivalent capacitance measuring device according to an embodiment of the present application;

[0041] Figure 2 A measurement test circuit diagram according to an embodiment of the present application;

[0042] Figure 3 A flow chart of a transformer coil longitudinal equivalent capacitance measuring method according to an embodiment of the present application.

[0043] In the figure, 1 is an oscilloscope, 2 is a pulse signal generator, 3 is an adjustable capacitance box, 4 is an isolation power supply, 5 is a box body, 6 is a universal wheel, 7 is a handrail, 8 is a pulse signal waveform measurement terminal post, 9 is a capacitance box voltage measurement terminal post, 10 is a pulse signal output terminal post, and 11 is a measured coil. DETAILED DESCRIPTION

[0044] In order to make the purpose, technical solutions and advantages of the embodiments of the present application more clear, the technical solutions in the embodiments of the present application will be described clearly and completely below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without any creative effort belong to the protection scope of the present application.

[0045] Embodiment 1:

[0046] The first aspect of the present application discloses a transformer coil longitudinal equivalent capacitance measuring device, specifically as shown in the figure, the device comprises: Figure 1

[0047] An oscilloscope 1, a pulse signal generator 2, an adjustable capacitance box 3, an isolation power supply 4 and a box body 5;

[0048] The oscilloscope 1, the pulse signal generator 2, the adjustable capacitance box 3 and the isolation power supply 4 are installed in the box body 5, the pulse signal generator 2 is connected with the adjustable capacitance box 3, the oscilloscope 1 is connected with the adjustable capacitance box 3, and the isolation power supply 4 provides power supply for the oscilloscope 1 and the pulse signal generator 2;

[0049] As shown in the figure, Figure 2 ​As shown, the pulse signal generator 2 outputs a waveform voltage to the measured coil 11 and the adjustable capacitor box 3, and adjusts the capacitance of the adjustable capacitor box 3 so that the voltage value of the capacitance of the adjustable capacitor box 3 is equal to the voltage value of the measured coil 11, at which time the capacitance of the capacitor box 3 is equal to the longitudinal equivalent capacitance of the measured coil 11.

[0050] In some embodiments, the device further comprises:

[0051] a capacitor box voltage measurement terminal 9, a pulse signal output terminal 10, and a measurement line;

[0052] The capacitor box voltage measurement terminal 9 and the pulse signal output terminal 10 are arranged on the box 5.

[0053] The oscilloscope 1 is connected to the adjustable capacitor box 3 through the capacitor box voltage measurement terminal 9.

[0054] One end of the measurement line is connected to the pulse signal output terminal 10, and the other end of the measurement line is connected to the measured coil 11.

[0055] In some embodiments, the device further comprises a pulse signal waveform measurement terminal 8.

[0056] The pulse signal waveform measurement terminal 8 is arranged on the box 5.

[0057] The first channel of the oscilloscope 1 is connected to the pulse signal waveform measurement terminal 8.

[0058] The second channel of the oscilloscope 1 is connected to the adjustable capacitor box 3 through the capacitor box voltage measurement terminal 9.

[0059] In some embodiments, the device further comprises:

[0060] universal wheels 6 and handrails 7.

[0061] The universal wheels 6 and the handrails 7 are installed on the box 5.

[0062] In some embodiments, the box 5 has four universal wheels 6 for easy movement and two handrails 7 to ensure the stability of the box.

[0063] In some embodiments, the specific structure of the isolation power supply 4 for providing power supply for the oscilloscope 1 and the pulse signal generator 2 comprises:

[0064] The box 5 has a main ground and a power supply, and the isolation power supply 4 provides power supply and protection ground for the oscilloscope 1 and the pulse signal generator 2, and provides protection ground for the adjustable capacitor box 4, which can filter out the interference signals of the ground net and the power supply.

[0065] In some embodiments, the pulse signal generator 2 is capable of waveform adjustment and outputting 0-400V continuous adjustable voltage suitable for various types of coils.

[0066] Embodiment 2:

[0067] The second aspect of the present application discloses a transformer coil longitudinal equivalent capacitance measurement method, which is applied to the device of any one of embodiments 1, and specifically as shown in Figure 3 The method comprises the following steps:

[0068] Step S1, zero the adjustable capacitance box 3, the box body 5 is grounded, and the pulse signal generator 2 is connected with the adjustable capacitance box 3;

[0069] Step S2, connect the first channel of the oscilloscope 1 with the pulse signal waveform measurement terminal post 8;

[0070] Step S3, connect the second channel of the oscilloscope 1 with the adjustable capacitance box 3 through the capacitance box voltage measurement terminal post 9;

[0071] Step S4, connect one end of the measurement line with the pulse signal output terminal post 10, and the other end of the measurement line is connected with the measured coil 11;

[0072] Step S5, adjust the pulse signal generator 2 to adjust the output waveform;

[0073] Step S6, adjust the capacitance of the adjustable capacitance box 3, so that the voltage value of the capacitance of the adjustable capacitance box 3 is equal to the voltage value of the measured coil 11, at this time, the capacitance of the capacitance box 3 is equal to the longitudinal equivalent capacitance of the measured coil 11.

[0074] In some embodiments, the certain waveform is a measured lightning impulse waveform with steep front time.

[0075] In some embodiments, the measured lightning impulse waveform with steep front time specifically requires:

[0076] The front of the measured lightning impulse waveform requires 0.9μs±10%, the tail time of the measured lightning impulse waveform is 50μs±20%, and the output voltage of the measured lightning impulse waveform is 100V.

[0077] In some embodiments, the adjustment of the capacitance of the adjustable capacitance box 3, so that the voltage value of the capacitance of the adjustable capacitance box 3 is equal to the voltage value of the measured coil 11 specifically comprises:

[0078] Adjusting the capacitance of the adjustable capacitance box 3, so that the voltage value of the capacitance of the adjustable capacitance box 3 is equal to 50V, at this time the capacitance of the capacitance box 3 is equal to the longitudinal equivalent capacitance of the measured coil 11. In summary, the technical solutions of various aspects of the present application have the following advantages compared with the prior art:

[0079] The present application provides a transformer coil longitudinal equivalent capacitance measuring device and method,

[0080] 1. The measurement of the transformer coil longitudinal equivalent capacitance can be completed in a very simple way, and the problem that the energy equivalent method under the steep wave cannot be calculated is solved.

[0081] 2. By connecting the transformer coil in the device, the problem of temporarily assembling the test loop is avoided, and the measurement work flow is simple.

[0082] 3. The pulse signal generator outputs a low voltage signal to complete the measurement, and the power supply problem of the measurement is solved.

[0083] 4. The device has been applied and popularized in the laboratory, and the test results are highly consistent with the design values, which has certain practical application significance.

[0084] Please note that the technical features of the above embodiments can be combined arbitrarily, in order to make the description simple, not all possible combinations of the technical features in the above embodiments are described, however, as long as the combination of the technical features does not exist contradictory, it should be considered as the scope of the present application. The above examples only express several embodiments of the present application, and the description is more specific and detailed, but it should not be interpreted as a limitation on the scope of the patent. It should be noted that for ordinary skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are within the scope of the present application. Therefore, the scope of the patent of the present application should be subject to the appended claims.

Claims

1. A device for measuring the longitudinal equivalent capacitance of a transformer coil, characterized in that, The device includes: Oscilloscope, pulse signal generator, adjustable capacitor bank, isolation power supply and enclosure; The oscilloscope, pulse signal generator, adjustable capacitor bank, and isolated power supply are installed inside the enclosure. The pulse signal generator is connected to the adjustable capacitor bank, and the oscilloscope is connected to the adjustable capacitor bank. The isolated power supply provides power to the oscilloscope and the pulse signal generator. The pulse signal generator outputs a voltage of a certain waveform to the coil under test and the adjustable capacitor box. The capacitance of the adjustable capacitor box is adjusted so that the voltage value of the adjustable capacitor box is equal to the voltage value of the coil under test. At this time, the capacitance of the capacitor box is equal to the longitudinal equivalent capacitance of the coil under test. The device further includes: Capacitor box voltage measurement terminals, pulse signal output terminals, and measurement leads; The capacitor box voltage measurement terminal and the pulse signal output terminal are located on the box body; The oscilloscope is connected to the adjustable capacitor box via the voltage measurement terminal of the capacitor box. One end of the measuring line is connected to the pulse signal output terminal, and the other end of the measuring line is connected to the coil under test.

2. The transformer coil longitudinal equivalent capacitance measuring device according to claim 1, characterized in that, The device further includes: pulse signal waveform measurement terminals; The pulse signal waveform measurement terminal is located on the enclosure; The first channel of the oscilloscope is connected to the pulse signal waveform measurement terminal; The second channel of the oscilloscope is connected to the adjustable capacitor box via the capacitor box voltage measurement terminal.

3. The transformer coil longitudinal equivalent capacitance measuring device according to claim 1, characterized in that, The device further includes: Casters and armrests; The casters and handrails are mounted on the housing.

4. The transformer coil longitudinal equivalent capacitance measuring device according to claim 1, characterized in that, The specific structure of the isolation power supply that provides power to the oscilloscope and pulse signal generator includes: The enclosure has a main ground and power supply. The isolation power supply provides power and protective grounding for the oscilloscope and the pulse signal generator, and provides protective grounding for the adjustable capacitor box.

5. The transformer coil longitudinal equivalent capacitance measuring device according to claim 1, characterized in that, The pulse signal generator can adjust the waveform and output a continuously adjustable voltage from 0 to 400V suitable for various types of coils.

6. A method for measuring the longitudinal equivalent capacitance of a transformer coil, characterized in that, The method is applied to the apparatus according to any one of claims 1-5, and the method comprises: Step S1: Zero the adjustable capacitor box, ground the box, and connect the pulse signal generator to the adjustable capacitor box. Step S2: Connect the first channel of the oscilloscope to the pulse signal waveform measurement terminal; Step S3: Connect the second channel of the oscilloscope to the adjustable capacitor box via the capacitor box voltage measurement terminal; Step S4: Connect one end of the measuring line to the pulse signal output terminal, and connect the other end of the measuring line to the coil under test; Step S5: Adjust the pulse signal generator to output a certain waveform; Step S6: Adjust the capacitance of the adjustable capacitor box so that the voltage value of the adjustable capacitor box is equal to the voltage value of the coil under test. At this time, the capacitance of the capacitor box is equal to the longitudinal equivalent capacitance of the coil under test.

7. The method for measuring the longitudinal equivalent capacitance of a transformer coil according to claim 6, characterized in that, The specified waveform is a measured lightning impulse waveform with a steep wavefront time.

8. The method for measuring the longitudinal equivalent capacitance of a transformer coil according to claim 7, characterized in that, The specific requirements for measuring lightning impulse waveforms with steep wavefront times include: The wavefront time for measuring the lightning impulse waveform should be 0.9μs±10%, the wavetail time should be 50μs±20%, and the output voltage of the lightning impulse waveform should be 100V.

9. The method for measuring the longitudinal equivalent capacitance of a transformer coil according to claim 8, characterized in that, Adjusting the capacitance of the adjustable capacitor box to make the voltage value of the adjustable capacitor box equal to the voltage value of the measured coil specifically includes: Adjust the capacitance of the adjustable capacitor box so that the voltage value of the capacitor box is equal to 50V. At this time, the capacitance of the capacitor box is equal to the longitudinal equivalent capacitance of the coil under test.

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