Direct-current resistance testing equipment

Abstract

The invention relates to a direct current resistance test device, which comprises a power supply device, an output interface assembly, a measurement interface assembly, a data acquisition device and a processing device, and is characterized in that the output interface assembly comprises at least one output interface, and under the control of the processing device, the power supply device can be connected with the data acquisition device through the output interface assembly; and applying a direct current test signal to at least one phase winding of the secondary circuit of the to-be-tested mutual inductor. And the data acquisition device can acquire a voltage signal on the winding on which the direct current test signal is applied through the measurement interface assembly, and filter and amplify the voltage signal to obtain a direct current voltage parameter. And finally, the processing device carries out analysis and calculation according to the DC voltage parameters acquired and sent by the data acquisition device, so that the DC resistance of the winding of the secondary circuit of the to-be-tested mutual inductor can be obtained. According to the scheme, alternating current interference signals in the voltage signals can be filtered out through the data acquisition device, the anti-interference capability is high, and the testing accuracy of the direct current resistance can be effectively improved.

Description

Technical Field

[0001] The present application relates to the field of electric power technology, and in particular to a DC resistance testing device. Background Art

[0002] In the power system, the DC resistance test of the secondary current and voltage circuits is an important test item before the equipment is put into operation. It is also the last checkpoint to prevent the potential transformer (PT) short circuit and the current transformer (CT) open circuit. It is of great significance to the safe and stable operation of the power system.

[0003] Currently, testers are required to use a multimeter to measure the DC resistance of the secondary side before putting it into operation. However, in actual scenarios, if the circuit breaker on the primary side of the equipment is closed, a large induced voltage will be generated in the secondary current loop. The multimeter is disturbed by the induced voltage and usually cannot measure the accurate DC resistance value. Summary of the invention

[0004] Based on this, it is necessary to provide a DC resistance testing device to address the problem that the DC resistance test of the secondary current and voltage circuits in the transformer equipment is easily disturbed, resulting in low test accuracy.

[0005] The present application provides a DC resistance testing device, comprising: a power supply device, an output interface component, a measurement interface component, a data acquisition device and a processing device, wherein the output interface component is connected to the power supply device, the output interface component comprises at least one output interface, one of the output interfaces is used to connect a phase winding of a secondary circuit of a transformer to be tested; the measurement interface component comprises at least one measurement interface, one of the measurement interfaces is used to connect a phase winding of a secondary circuit of the transformer to be tested; the data acquisition device is connected to the measurement interface component, the data acquisition device is used to acquire a voltage signal of a winding of a secondary circuit of the transformer to be tested, and obtain a DC voltage parameter after filtering and amplifying the voltage signal; the processing device is connected to the power supply device and the data acquisition device respectively, and the processing device is used to perform analysis and calculation according to the DC voltage parameters to determine the DC resistance of the winding of the secondary circuit of the transformer to be tested.

[0006] In one embodiment, the data acquisition device includes a low-pass filter, a signal amplifier and an analog-to-digital converter connected in sequence, the low-pass filter is connected to the measurement interface component, and the analog-to-digital converter is connected to the processing device.

[0007] In one of the embodiments, the device further includes a resistive load, and the power supply device is connected to the output interface component via the resistive load.

[0008] In one embodiment, the equivalent resistance of the resistive load is greater than or equal to 50 ohms.

[0009] In one embodiment, the output interface component includes three output interfaces, and the measurement interface component includes three measurement interfaces.

[0010] In one of the embodiments, the device further comprises a human-computer interaction device, and the human-computer interaction device is connected to the processing device.

[0011] In one embodiment, the human-computer interaction device is a touch display screen.

[0012] In one of the embodiments, the device further comprises an information prompting device, and the information prompting device is connected to the processing device.

[0013] In one embodiment, the power supply device is a constant current source device.

[0014] In one of the embodiments, the processing device further includes a communication interface, and the processing device is further configured to store the measurement data, and transmit the stored measurement data to the terminal device when the communication interface is connected to the terminal device.

[0015] The above-mentioned DC resistance test equipment includes a power supply device, an output interface component, a measurement interface component, a data acquisition device and a processing device. The output interface component includes at least one output interface. Under the control of the processing device, the power supply device can apply a DC test signal to at least one phase winding of the secondary circuit of the transformer to be tested through the output interface component. After that, the data acquisition device can collect the voltage signal on the winding to which the DC test signal is applied through the measurement interface component, and obtain the DC voltage parameter after filtering and amplifying the voltage signal. Finally, the processing device analyzes and calculates according to the DC voltage parameters collected and sent by the data acquisition device, and can obtain the DC resistance of the winding of the secondary circuit of the transformer to be tested. Through the above scheme, the DC resistance test can be performed on one-phase winding or multi-phase winding of the secondary circuit of the transformer to be tested at the same time, and the AC interference signal in the voltage signal can be filtered out by the data acquisition device, which has a high anti-interference ability and can effectively improve the test accuracy of the DC resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the conventional technology, the drawings required for use in the embodiments or the conventional technology descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0017] FIG1 is a schematic diagram of the structure of a DC resistance test device in one embodiment of the present application;

[0018] FIG2 is a schematic diagram of the structure of a DC resistance test device in another embodiment of the present application;

[0019] FIG3 is a schematic diagram of the structure of a DC resistance test device in another embodiment of the present application;

[0020] FIG4 is a schematic diagram of the structure of a DC resistance testing device in yet another embodiment of the present application.

[0021] Description of reference numerals:

[0022] 10-power supply device, 20-output interface component, 21-output interface, 30-measurement interface component, 31-measurement interface, 40-data acquisition device, 50-processing device, 41-low-pass filter, 42-signal amplifier, 43-analog-to-digital converter, 60-human-computer interaction device. DETAILED DESCRIPTION

[0023] In order to facilitate the understanding of the present application, the present application will be described more fully below with reference to the relevant drawings. The preferred embodiments of the present application are provided in the drawings. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present application more thorough and comprehensive.

[0024] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0025] It is understood that the terms "first", "second", etc. used in this application may be used herein to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish a first element from another element. For example, without departing from the scope of this application, a first resistor may be referred to as a second resistor, and similarly, a second resistor may be referred to as a first resistor. Both the first resistor and the second resistor are resistors, but they are not the same resistor.

[0026] It can be understood that the “connection” in the following embodiments should be understood as “electrical connection”, “communication connection”, etc. if the connected circuits, modules, units, etc. have electrical signals or data transmission between each other.

[0027] It can be understood that “at least one” means one or more, “plurality” means two or more, and “at least part of an element” means part or all of an element.

[0028] When used herein, the singular forms "a", "an", and "said / the" may also include plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "include / comprise" or "have" and the like specify the presence of stated features, wholes, steps, operations, components, parts, or combinations thereof, but do not exclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts, or combinations thereof. At the same time, the term "and / or" used in this specification includes any and all combinations of the relevant listed items.

[0029] The DC resistance testing equipment provided in the present application is used to perform a DC resistance test on the winding of the secondary circuit of a current transformer or a voltage transformer. During the actual testing process, a single-phase winding can be connected to perform a single-phase DC resistance test as required; or multiple phase windings can be connected at the same time to perform multiple DC resistance tests to improve the testing efficiency. The specific selection can be made according to the actual scenario.

[0030] Please refer to Figure 1. The present application provides a DC resistance testing device, including: a power supply device 10, an output interface component 20, a measurement interface component 30, a data acquisition device 40 and a processing device 50. The output interface component 20 is connected to the power supply device 10, and the output interface component 20 includes at least one output interface 21, and one output interface 21 is used to connect a phase winding of the secondary circuit of the transformer to be tested (not shown in the figure); the measurement interface component 30 includes at least one measurement interface 22, and one measurement interface 22 is used to connect a phase winding of the secondary circuit of the transformer to be tested; the data acquisition device 40 is connected to the measurement interface component 30, and the data acquisition device 40 is used to collect the voltage signal of the winding of the secondary circuit of the transformer to be tested, and obtain the DC voltage parameter after filtering and amplifying the voltage signal; the processing device 50 is connected to the power supply device 10 and the data acquisition device 40 respectively, and the processing device 50 is used to analyze and calculate according to the DC voltage parameter to determine the DC resistance of the winding of the secondary circuit of the transformer to be tested.

[0031] Specifically, the power supply device 10 is a device that can transmit electric energy to the windings in the secondary circuit of the transformer to be tested through the output interface component 20. The output interface component 20 is an interface device used to match the windings of the secondary circuit of the transformer to be tested to transmit electric energy to different windings. The measurement interface component 30 is an interface device used to match the windings of the secondary circuit of the transformer to be tested to transmit the voltage signals at both ends of different windings to the data acquisition device 40. The data acquisition device 40 is a device that can realize voltage signal acquisition and filter out signals such as AC interference or ripple interference in the collected voltage signal, and only retain the DC signal. The processing device 50 is a control device with certain data storage and processing functions, which can issue control instructions to the power supply device 10 according to actual test requirements, so that the power supply device 10 outputs a suitable DC test signal. The transformer to be tested is a current transformer or a voltage transformer waiting for a DC resistance test.

[0032] In actual scenarios, the primary and secondary sides of a current transformer or a voltage transformer are connected through electromagnetic coupling. If there is current on the primary side due to the circuit breaker not being closed or the environment being affected during a DC resistance test, an AC signal will be generated on the secondary side through AC coupling, which will interfere with the DC resistance test and affect the accuracy of the electrical signal measured on the secondary side.

[0033] In the solution of this embodiment, the output interface component 20 is provided with at least one output interface 21, each of which can output a DC test signal. According to actual test requirements, one or more output interfaces 21 can be connected to one end of a single-phase or multi-phase winding to provide a DC current signal for the winding. The measurement interface component 30 is provided with at least one measurement interface 22, each of which can be connected to a single-phase winding, and the voltage signal at both ends of the winding is transmitted to the data acquisition device 40 through the measurement interface component 30. It can be understood that the winding connected to the measurement interface 22 should be consistent with the winding connected to the output interface 21 to ensure that the measurement is carried out normally.

[0034] After the data acquisition device 40 obtains the voltage signal, since the voltage signal is a mixed signal, including not only DC voltage but also AC interference or DC ripple interference and other components, the data acquisition device 40 needs to process it to filter out the clutter generated in a strong interference environment and the ripple interference generated by the DC power supply, and only retain the DC signal as the DC voltage parameter generated when the DC test signal flows through the winding of the secondary circuit of the transformer to be tested.

[0035] It should be noted that, in one embodiment, when there is a need to test multiple phase windings at the same time, in order to improve the test accuracy, the electric energy output by the power supply device 10 can be divided into multiple identical test currents after being processed by the output interface component 20, and flow into different windings respectively. Specifically, the test current flowing into each phase should be consistent with the DC current output by the power supply device 10, so that the DC current test does not need to be performed again during the test process.

[0036] It is understandable that the processing device 50 is not the only one that calculates the DC resistance of the winding of the secondary circuit of the transformer to be tested based on the DC voltage parameter analysis. In one embodiment, the power supply device 10 can provide a DC current signal of the same magnitude to each phase winding under the control of the processing device 50 according to actual needs. Then, it is only necessary to collect the DC voltage parameters at both ends of the winding, and use the ratio of the DC voltage parameter to the DC current signal as the DC resistance of the phase winding. That is, , , ,in, , and are the DC resistance values ​​of phase A winding, phase B winding and phase C winding respectively, , and are the DC voltage parameters of phase A winding, phase B winding and phase C winding respectively, , and are the current values ​​of the DC test signals input to the A-phase winding, the B-phase winding, and the C-phase winding respectively.

[0037] In another embodiment, in order to improve the test accuracy, the DC resistance test equipment can also be equipped with a current acquisition device to collect the current signal flowing through each phase winding, and after filtering, amplifying and other processing on the current signal, a DC current signal is obtained. The specific selection can be made based on actual needs.

[0038] The DC resistance test device comprises a power supply device 10, an output interface component 20, a measurement interface component 30, a data acquisition device 40 and a processing device 50. The output interface component 20 comprises at least one output interface 21. Under the control of the processing device 50, the power supply device 10 can apply a DC test signal to at least one phase winding of the secondary circuit of the transformer to be tested through the output interface component 20. After that, the data acquisition device 40 can collect the voltage signal on the winding to which the DC test signal is applied through the measurement interface component 30, and obtain the DC voltage parameter after filtering and amplifying the voltage signal. Finally, the processing device 50 analyzes and calculates the DC voltage parameter collected and sent by the data acquisition device 40 to obtain the DC resistance of the winding of the secondary circuit of the transformer to be tested. Through the above scheme, the DC resistance test can be performed on one phase winding or multiple phase windings of the secondary circuit of the transformer to be tested at the same time, and the AC interference signal in the voltage signal can be filtered out through the data acquisition device 40, which has a high anti-interference ability and can effectively improve the test accuracy of the DC resistance.

[0039] Please refer to FIG. 2 . In one embodiment, the data acquisition device 40 includes a low-pass filter 41 , a signal amplifier 42 , and an analog-to-digital converter 43 connected in sequence. The low-pass filter 41 is connected to the measurement interface component 30 , and the analog-to-digital converter 43 is connected to the processing device 50 .

[0040] Specifically, in the measurement link, since the three-phase winding of the secondary circuit of the transformer to be tested is generally in a strong interference environment, there will often be interference from the AC signal during signal transmission, and when the signal is amplified, according to the numerical design of the amplification factor, the AC signal will also be amplified together, resulting in a large ripple interference. The three-phase DC resistance test of the secondary circuit belongs to a small resistance test, and this interference will cause an increase in the discrete value of the measurement result, which has a great impact on the accuracy of the measurement result. Therefore, when performing signal acquisition and amplification, a low-pass filter 41 is required to first remove the interference of the AC signal from the DC signal.

[0041] After that, the DC signal without AC interference or ripple interference is amplified and processed by analog-to-digital conversion to obtain DC voltage parameters representing the DC voltage signal at both ends of the three-phase winding, so as to calculate the DC resistance.

[0042] Through this solution, the voltage signal of the winding of the secondary circuit is processed by the low-pass filter 41, the signal amplifier 42 and the analog-to-digital converter 43 to obtain a high-accuracy DC voltage parameter, thereby improving the accuracy of the DC voltage parameter.

[0043] Please refer to FIG. 3 . In one embodiment, the DC resistance testing device further includes a resistive load R. The power supply device 10 is connected to the output interface component 20 via the resistive load R.

[0044] Specifically, in order to prevent the measurement loop resistance of the test equipment from being too small, causing the secondary loop of the transformer to be tested to be shunted during the operating interval, causing the operating equipment to trip and increasing the measurement risk, a resistive load R can be connected in series in the measurement loop to reduce the test risk.

[0045] It can be understood that the resistive load R can be set at any position as long as it can increase the resistance of the test loop. For example, the resistive load R is connected in series between the power supply device 10 and the output interface component 20. In another embodiment, the resistive load R can also be set in the output interface component 20, and each output interface 21 is connected to a resistive load R, and the selection can be made in combination with actual needs.

[0046] It should be noted that the type of resistive load R is not unique, and it can be an electrical load such as a resistor that can exhibit a certain resistance value, without specific limitation. For ease of understanding, the following embodiments are explained by taking the resistive load R as a resistor as an example, wherein the resistor can be a single resistor (fixed resistor or variable resistor) or a resistor component formed by multiple resistors connected in series and / or in parallel, without specific limitation.

[0047] It should be noted that in order to prevent the secondary circuit of the transformer to be tested from shunting, the resistance value of the resistive load R needs to be set to be sufficiently large. For example, in one embodiment, the equivalent resistance value of the resistive load R is greater than or equal to 50 ohms. Further, in one embodiment, the resistive load R can also be configured to have an equivalent resistance value greater than 100 ohms, which can be selected in combination with actual needs.

[0048] In one embodiment, the output interface component 20 includes three output interfaces 21 , and the measurement interface component 30 includes three measurement interfaces 22 .

[0049] Specifically, the number of output interfaces 21 of the output interface component 20 and the number of measurement interfaces 22 of the measurement interface component 30 are not unique. In one embodiment, in order to enable each winding to which a DC test signal is applied to realize a DC resistance test, the number of output interfaces 21 needs to be set consistent with the number of measurement interfaces 22.

[0050] Furthermore, considering that the electrical signals transmitted by the current power system are generally three-phase electrical signals, the output interface 21 of the output interface component 20 can be set to three, and the measurement interface 22 of the measurement interface component 30 can be set to three. In this way, in actual measurement, the DC resistance test of one-phase winding, any two-phase winding or three-phase winding can be performed simultaneously according to the needs. If three-phase simultaneous measurement is selected, the test efficiency can be increased by three times compared with the multimeter test.

[0051] Please refer to FIG. 4 . In one embodiment, the DC resistance testing device further includes a human-computer interaction device 60 . The human-computer interaction device 60 is connected to the processing device 50 .

[0052] Specifically, the human-machine interaction device 60 is a device for realizing information interaction between the tester and the DC resistance test device. Through the human-machine interaction device 60, the test results can be displayed to the tester; and / or the tester can configure the test parameters for the DC resistance test device through the human-machine interaction device 60, such as changing the DC test signal output by the power supply device 10, etc., which is not specifically limited. The scheme of this embodiment can effectively improve the convenience of using the DC resistance test device through the setting of the human-machine interaction device 60.

[0053] It should be noted that the type of human-machine interaction device 60 is not unique. In one embodiment, the human-machine interaction device 60 may be a mechanical key electrically connected to the processing device 50, and the setting of the test parameters is achieved by pressing the mechanical key. In another embodiment, the human-machine interaction device 60 may also include a display screen and a mechanical key, and the setting parameters or test results may also be displayed on the display screen.

[0054] Furthermore, in one embodiment, the human-computer interaction device 60 is a touch display screen.

[0055] Specifically, the touch display screen is a display screen with touch interaction function and display function. The solution of this embodiment realizes human-computer interaction with the touch display screen to improve the convenience of interaction.

[0056] It is understandable that the size and type of the touch display screen are not unique. In a more detailed embodiment, a capacitive touch screen can be used as the touch display screen.

[0057] In one embodiment, the DC resistance testing device further includes an information prompting device, and the information prompting device is connected to the processing device 50 .

[0058] Specifically, in the scheme of this embodiment, the DC resistance test equipment has a very large test range, which can be adjusted according to actual needs. For example, in one embodiment, the DC resistance test equipment adopts a primary current clamp interface design of 0A (ampere)-1500A, and a measurement range of 0.1Ω (ohm)-1000kΩ (kiloohm). When the DC resistance is detected to be within a certain resistance value (for example, 10 ohms), the processing device 50 can control the information prompt device to output a prompt signal, so as to implement operations such as cable core alignment.

[0059] It should be pointed out that the type of information prompt device is not unique, and it can be an alarm such as sound or light, for example, a buzzer, a signal indicator light, etc. There is no specific limitation, and it can be selected according to actual needs.

[0060] In one embodiment, the power supply device 10 is a constant current source device.

[0061] Specifically, the constant current source device is a power source that can output a stable current that does not change with load changes. Further, considering the solution of the embodiment of the present application, the constant current device is specifically a DC constant current device for inputting a DC test signal to the three phases of the secondary circuit of the transformer to be tested.

[0062] In this way, during the actual test process, under the control of the processing device 50, the DC constant current device outputs a DC power supply test signal to the three corresponding windings A, B, and C through the three output interfaces 21 of the output interface component 20. The data acquisition device 40 collects the changing DC signal and the residual AC information, and obtains the DC voltage parameters after filtering, amplification, and analog-to-digital conversion.

[0063] In one embodiment, the processing device 50 further includes a communication interface, and the processing device 50 is further configured to store the measurement data, and transmit the stored measurement data to the terminal device when the communication interface is connected to the terminal device.

[0064] Specifically, in this embodiment, the processing device 50 has data storage and clearing functions, and can store a certain amount of measurement data according to actual needs. When there is a subsequent call demand, the processing device 50 can be accessed through a terminal device such as a mobile phone or a tablet computer to export the stored measurement data, thereby improving the convenience of using the DC resistance test device.

[0065] It can be understood that in other embodiments, the above-mentioned filtering, amplification and analog-to-digital conversion functions can also be configured in the processing device 50, and the data acquisition device 40 only has a voltage signal acquisition function, which transmits the collected mixed voltage signal to the processing device 50, and further performs filtering, amplification and analog-to-digital conversion at the processing device 50 to obtain DC voltage parameters.

[0066] The type of the processing device 50 is not limited, and may be an MCU (Microcontroller Unit), a CPU (Central Processing Unit), etc., without specific limitation, and may be selected according to actual needs.

[0067] Furthermore, in one embodiment, the processing device 50 also has a wireless communication module, which can communicate with the terminal device or server through the wireless communication module, so as to transmit the DC resistance acquisition result to the terminal device or server in real time for storage, so as to facilitate subsequent call or viewing, without specific limitation.

[0068] It should be pointed out that, in one embodiment, in order to further improve the test efficiency of the DC resistance test equipment, a processor with higher data processing efficiency can be used as the processing device 50, such as a Raspberry Pi quad-core high-speed processor, etc. In this way, accurate test results can be obtained in a shorter time (e.g., two seconds), which can greatly save time costs.

[0069] In the description of this specification, the description with reference to the terms "some embodiments", "other embodiments", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic description of the above terms does not necessarily refer to the same embodiment or example.

[0070] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0071] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be construed as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent application shall be subject to the attached claims.

Claims

1. A DC resistance test device, characterized in that: include: Power supply unit; An output interface component, connected to the power supply device, the output interface component includes at least one output interface, one of the output interfaces is used to connect a phase winding of the secondary circuit of the transformer to be tested; A measurement interface assembly, comprising at least one measurement interface, wherein one of the measurement interfaces is used to connect a phase winding of a secondary circuit of the transformer to be measured; A data acquisition device connected to the measurement interface assembly, the data acquisition device is used to collect the voltage signal of the winding of the secondary circuit of the transformer to be measured, and obtain a DC voltage parameter after filtering and amplifying the voltage signal; A processing device is connected to the power supply device and the data acquisition device respectively, and the processing device is used to control the power supply device to output a DC test signal, and to perform analysis and calculation based on the DC voltage parameters to determine the DC resistance of the winding of the secondary circuit of the transformer to be tested.

2. The DC resistance test device according to claim 1, characterized in that: The data acquisition device comprises a low-pass filter, a signal amplifier and an analog-to-digital converter which are connected in sequence, the low-pass filter is connected to the measurement interface component, and the analog-to-digital converter is connected to the processing device.

3. The DC resistance test device according to claim 1, characterized in that: The device further comprises a resistive load, and the power supply device is connected to the output interface component via the resistive load.

4. The DC resistance test device according to claim 3, characterized in that: The equivalent resistance of the resistive load is greater than or equal to 50 ohms.

5. The DC resistance test device according to claim 1, characterized in that: The output interface component includes three output interfaces, and the measurement interface component includes three measurement interfaces.

6. The DC resistance test device according to any one of claims 1 to 5, characterized in that: The device also includes a human-computer interaction device, and the human-computer interaction device is connected to the processing device.

7. The DC resistance test device according to claim 6, characterized in that: The human-computer interaction device is a touch display screen.

8. The DC resistance test device according to any one of claims 1 to 5, characterized in that: The device also includes an information prompting device, which is connected to the processing device.

9. The DC resistance test device according to any one of claims 1 to 5, characterized in that: The power supply device is a constant current source device.

10. The DC resistance test device according to any one of claims 1 to 5, characterized in that: The processing device further comprises a communication interface, and the processing device is further configured to store measurement data, and transmit the stored measurement data to the terminal device when the communication interface is connected to the terminal device.

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