Self-calibrating dc voltage divider and method and apparatus for testing thereof

Abstract

The application discloses a self-calibrating DC voltage divider, which comprises a high-voltage arm and a low-voltage arm connected in series; the high-voltage arm comprises a first resistor and a first capacitor connected in parallel; in the low-voltage arm, one end of a first resistor-capacitor unit is connected to one end of the high-voltage arm, the other end of the first resistor-capacitor unit is connected to the other end of a second resistor-capacitor unit, and a switch is connected in parallel to the two ends of the second resistor-capacitor unit. The application also discloses a testing method and a testing device for the self-calibrating DC voltage divider, wherein the switch is closed, a DC voltage is applied to the input end of the DC voltage divider, and a first output voltage is obtained; the switch is opened, and a second output voltage is obtained; the relative variation of the first resistor of the high-voltage arm is calculated, so that the resistance value of the first resistor of the high-voltage arm is obtained. The technical scheme adjusts different low-voltage arm parameters through the on and off states of the switch, obtains different output voltage values through twice testing under the same input voltage, and calculates the actual resistance value of the high-voltage arm, so that the detection of the resistance value of the high-voltage arm is realized.

Description

Technical Field

[0001] This invention belongs to the field of DC voltage measurement technology, specifically relating to a self-calibrating DC voltage divider and its testing method and device. Background Technology

[0002] In recent years, ultra-high voltage direct current (UHVDC) transmission and flexible direct current (DC) transmission have developed rapidly in my country. DC voltage dividers (or "DC voltage transformers") are key equipment in DC converter stations, used for real-time monitoring of DC operating voltage, harmonic voltage, and fault step voltage of DC buses such as ±800kV, ±400kV, and ±100kV. The accuracy of DC measurement during normal operation is usually 0.5%.

[0003] DC voltage dividers generally employ the resistive-capacitive voltage divider principle. Both the high-voltage and low-voltage arms consist of parallel connections of precision resistors and capacitors. Precision resistors are the core components of DC voltage dividers, especially the high-voltage arm resistors, which operate at high voltages and have large resistance values, making them susceptible to temperature and voltage fluctuations. Furthermore, the high-voltage arm resistors typically consist of hundreds or even thousands of discrete resistors connected in series and parallel, making it difficult to detect abnormalities in individual resistors or poor solder joints. With the trend towards complete self-sufficiency and control over critical power equipment, the manufacturing process and some performance indicators of domestic precision resistors still lag behind those of foreign counterparts. Long-term stability under high voltage needs further verification, necessitating strengthened monitoring of the high-voltage arm resistance values.

[0004] Regular maintenance of DC voltage dividers within converter stations presents challenges in accurately measuring the high-voltage arm resistance, which can reach hundreds of MΩ. Furthermore, direct measurement is affected by parallel capacitors, leading to inaccurate results. On-site, only a relatively low DC voltage of around 100kV can typically be applied, and there are usually no standard DC voltage transformers available for reference, making it impossible to obtain accurate actual applied voltage values. Consequently, it's impossible to deduce the accurate high-voltage arm resistance value by testing the actual turns ratio under applied voltage. The lack of convenient and effective methods to inspect minor variations in the high-voltage arm resistance within the DC voltage divider, even those exceeding permissible limits, hinders equipment maintenance. Summary of the Invention

[0005] The purpose of this invention is to provide a self-calibrating DC voltage divider and its testing method and device. By adjusting the switch to different low-voltage arm parameters in the on / off state, different output voltage values ​​are obtained in two tests under the same input voltage, and the actual high-voltage arm resistance value is calculated, thereby realizing the detection of the high-voltage arm resistance value.

[0006] To achieve the above objectives, the solution of the present invention is:

[0007] A self-calibrating DC voltage divider, comprising a high-voltage arm and a low-voltage arm connected in series;

[0008] The high-voltage arm includes a first resistor and a first capacitor, which are connected in parallel.

[0009] The low-voltage arm includes a first RC unit, a second RC unit, and a switch. One end of the first RC unit is connected to one end of the high-voltage arm, and the other end of the first RC unit is connected to the other end of the second RC unit. The switch is connected in parallel across the two ends of the second RC unit. The first RC unit includes a second resistor and a second capacitor, which are connected in parallel. The second RC unit includes a third resistor and a third capacitor, which are connected in parallel.

[0010] The input terminals of the DC voltage divider are the other end of the high voltage arm and the other end of the second resistor-capacitor unit in the low voltage arm, and the output terminals of the DC voltage divider are the two ends of the low voltage arm.

[0011] We have R1*C1=R2*C2=R3*C3, where R1, R2, and R3 are the resistance values ​​of the first, second, and third resistors, respectively, and C1, C2, and C3 are the resistance values ​​of the first, second, and third capacitors, respectively.

[0012] The resistance value of the first resistor mentioned above is in the hundreds of MΩ range, and it can be a mesh resistor, a rod resistor, or several resistor elements connected in series, parallel or mixed.

[0013] The resistance values ​​of the second and third resistors mentioned above are in the hundreds or tens of kΩ range.

[0014] The high-voltage arm is installed inside a sealed, gas-filled, or oil-filled hollow insulator, while the low-voltage arm is installed inside a low-voltage terminal box that can be opened.

[0015] The test method for the self-calibrating DC voltage divider described above includes,

[0016] When the control switch is closed, a DC voltage is applied to the input terminal of the DC voltage divider to obtain the first output voltage of the DC voltage divider.

[0017] The control switch is turned on to maintain the aforementioned applied DC voltage and obtain the second output voltage of the DC voltage divider.

[0018] Calculate the relative change in the resistance of the first resistor in the high-voltage arm to determine its resistance value.

[0019] Specifically, obtaining the first output voltage / second output voltage of the DC voltage divider includes waiting for the output voltage to stabilize, and then taking the average value of the output voltage of the DC voltage divider as the first output voltage / second output voltage.

[0020] Specifically, the calculation of the relative change in the first resistance of the high-voltage arm includes calculating the relative change in the first resistance of the high-voltage arm, δR1, using the following formula:

[0021]

[0022] Where R1 is the initial resistance value of the first resistor of the high-voltage arm, R2 is the resistance value of the second resistor of the low-voltage arm, and R3 is the resistance value of the third resistor of the low-voltage arm; U2 is the first output voltage of the DC voltage divider, and U2' is the second output voltage of the DC voltage divider.

[0023] The test apparatus for the self-calibrating DC voltage divider described above includes,

[0024] The first output voltage acquisition module is configured to acquire the first output voltage of the DC voltage divider when the switch is closed and a DC voltage is applied to the input terminal of the DC voltage divider;

[0025] The first output voltage acquisition module is configured to acquire the second output voltage of the DC voltage divider when the switch is turned on and a DC voltage is applied to the input terminal of the DC voltage divider; and

[0026] The resistance change calculation module is configured to calculate the relative change in the first resistance of the high-voltage arm, thereby obtaining the resistance value of the first resistance of the high-voltage arm.

[0027] The first output voltage acquisition module described above acquires the first output voltage of the DC voltage divider by, after waiting for the output voltage to stabilize, acquiring the average value of the output voltage of the DC voltage divider multiple times as the first output voltage;

[0028] The second output voltage acquisition module acquires the second output voltage of the DC voltage divider by waiting for the output voltage to stabilize and then taking the average value of the output voltage of the DC voltage divider as the second output voltage.

[0029] The aforementioned resistance change calculation module calculates the relative change in the first resistance of the high-voltage arm, including calculating the relative change in the first resistance of the high-voltage arm δR1 using the following formula:

[0030]

[0031] Where R1 is the initial resistance value of the first resistor of the high-voltage arm, R2 is the resistance value of the second resistor of the low-voltage arm, and R3 is the resistance value of the third resistor of the low-voltage arm; U2 is the first output voltage of the DC voltage divider, and U2' is the second output voltage of the DC voltage divider.

[0032] A computer device includes a memory, a processor, and a computer program stored in the memory and executable on the processor; when the processor executes the computer program, it implements the steps of the test method as described above.

[0033] A computer-readable storage medium storing a computer program; when executed by a processor, the computer program implements the steps of the test method as described above.

[0034] The beneficial effects of this invention, based on the parallel RC DC voltage divider, include at least the following: By setting two series-connected RC units as the low-voltage arm, the low-voltage arm parameters can be adjusted by switching them on and off. Under the same input voltage, two tests yield different output voltage values. Therefore, without a standard DC voltage transformer as a reference, the actual high-voltage arm resistance value can be calculated, and the relative change in high-voltage arm resistance can be obtained, thus enabling the detection of the high-voltage arm resistance value. Based on the obtained relative change in high-voltage arm resistance, the normal operating status of the DC voltage divider can be determined, guiding operation and maintenance. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of the circuit structure of the DC voltage divider of the present invention;

[0036] Figure 2 This is a flowchart of the testing method of the present invention. Detailed Implementation

[0037] The specific embodiments of the present invention will be described in more detail below with reference to the accompanying drawings and examples, so as to better understand the solutions of the present invention and the advantages of its various aspects. However, the specific embodiments and examples described below are for illustrative purposes only and are not intended to limit the present invention.

[0038] The present invention provides a self-calibrating DC voltage divider, comprising a high-voltage arm and a low-voltage arm connected in series;

[0039] The high-voltage arm includes a first resistor and a first capacitor, which are connected in parallel; wherein, the resistance of the first resistor is in the hundreds of MΩ range, and it adopts a mesh resistor, a rod resistor, or several resistor elements connected in series, in parallel, or in a mixed manner.

[0040] The low-voltage arm includes a first RC unit, a second RC unit, and a switch. One end of the first RC unit is connected to one end of the high-voltage arm, and the other end of the first RC unit is connected to the other end of the second RC unit. The switch is connected in parallel across the two ends of the second RC unit. The first RC unit includes a second resistor and a second capacitor, which are connected in parallel. The second RC unit includes a third resistor and a third capacitor, which are connected in parallel. The resistance values ​​of the second and third resistors are in the hundreds or tens of kΩ range.

[0041] The input terminals of the DC voltage divider are the other end of the high voltage arm and the other end of the second resistor-capacitor unit in the low voltage arm, and the output terminals of the DC voltage divider are the two ends of the low voltage arm.

[0042] We have R1*C1=R2*C2=R3*C3, where R1, R2, and R3 are the resistance values ​​of the first, second, and third resistors, respectively, and C1, C2, and C3 are the resistance values ​​of the first, second, and third capacitors, respectively.

[0043] The high-voltage arm is installed inside a sealed, gas-filled, or oil-filled hollow insulator, while the low-voltage arm is installed inside a low-voltage terminal box that can be opened.

[0044] The present invention also provides a test method for the aforementioned self-calibrating DC voltage divider, comprising:

[0045] When the control switch is closed, a DC voltage is applied to the input terminal of the DC voltage divider to obtain the first output voltage of the DC voltage divider.

[0046] The control switch is turned on to maintain the aforementioned applied DC voltage and obtain the second output voltage of the DC voltage divider.

[0047] Calculate the relative change in the resistance of the first resistor in the high-voltage arm to determine its resistance value.

[0048] The process of obtaining the first output voltage / second output voltage of the DC voltage divider includes waiting for the output voltage to stabilize, and then taking the average value of the output voltage of the DC voltage divider as the first output voltage / second output voltage.

[0049] The calculation of the relative change in the first resistance of the high-voltage arm includes using the following formula to calculate the relative change in the first resistance of the high-voltage arm, δR1:

[0050]

[0051] Where R1 is the initial resistance value of the first resistor of the high-voltage arm, R2 is the resistance value of the second resistor of the low-voltage arm, and R3 is the resistance value of the third resistor of the low-voltage arm; U2 is the first output voltage of the DC voltage divider, and U2' is the second output voltage of the DC voltage divider.

[0052] The present invention also provides a test apparatus for the aforementioned self-calibrating DC voltage divider, comprising,

[0053] The first output voltage acquisition module is configured to acquire the first output voltage of the DC voltage divider when the switch is closed and a DC voltage is applied to the input terminal of the DC voltage divider;

[0054] The first output voltage acquisition module is configured to acquire the second output voltage of the DC voltage divider when the switch is turned on and a DC voltage is applied to the input terminal of the DC voltage divider; and

[0055] The resistance change calculation module is configured to calculate the relative change in the first resistance of the high-voltage arm, thereby obtaining the resistance value of the first resistance of the high-voltage arm.

[0056] The first output voltage acquisition module acquires the first output voltage of the DC voltage divider by waiting for the output voltage to stabilize and then taking the average value of the output voltage of the DC voltage divider as the first output voltage.

[0057] The second output voltage acquisition module acquires the second output voltage of the DC voltage divider by waiting for the output voltage to stabilize and then taking the average value of the output voltage of the DC voltage divider as the second output voltage.

[0058] The resistance change calculation module calculates the relative change in the first resistance of the high-voltage arm, including calculating the relative change δR1 of the first resistance of the high-voltage arm using the following formula:

[0059]

[0060] Where R1 is the initial resistance value of the first resistor of the high-voltage arm, R2 is the resistance value of the second resistor of the low-voltage arm, and R3 is the resistance value of the third resistor of the low-voltage arm; U2 is the first output voltage of the DC voltage divider, and U2' is the second output voltage of the DC voltage divider.

[0061] like Figure 1 As shown, this embodiment of the invention provides a self-calibrating DC voltage divider, including a high-voltage arm and a low-voltage arm connected in series. Both the high-voltage arm and the low-voltage arm are parallel resistors and capacitors. The high-voltage arm is composed of a resistor R1 and a capacitor C1 connected in parallel. The low-voltage arm is composed of two series-connected RC units, including a resistor R2, a capacitor C2, a resistor R3, and a capacitor C3. R2 and R3 are connected in parallel with C2 and C3 respectively, and then connected in series. A switch S1 is connected in parallel across R3 and C3. The relationship between the resistors and capacitors is R1*C1 = R2*C2 = R3*C3. The input voltage is applied across the voltage divider, and the output voltage is from the low-voltage arm.

[0062] The high-voltage arm resistor R1 has a resistance value in the hundreds of MΩ range, operates under high voltage, and consists of multiple resistor elements connected in series and parallel, or uses a mesh resistor or rod resistor with a certain length.

[0063] The low-voltage arm resistors, including R2 and R3, have resistance values ​​in the hundreds or tens of kΩ range. They operate at low voltage and are precision resistors with high stability and low temperature drift.

[0064] During normal operation, switch S1 is closed, and R3 and C3 do not participate in voltage division.

[0065] In self-calibration mode, switch S1 is open, and R3 and C3 participate in voltage division.

[0066] Preferably, depending on the operating voltage and installation space, the high-voltage arm is installed inside a sealed, gas-filled, or oil-filled hollow insulator, and the low-voltage arm is installed inside an openable low-voltage terminal box, thereby facilitating the operation of the switch S1 inside the low-voltage arm.

[0067] Table 1 below shows the design parameters of a ±800kV DC voltage divider in an embodiment of the present invention. R2 and R3 operate at voltages less than 100V, operating under low voltage conditions. They are high-stability, low-temperature-drift precision resistors, and their resistance values ​​can be easily measured. Under normal operating conditions, the resistance values ​​of R2 and R3 can be considered to remain unchanged. Capacitors C1, C2, and C3 serve to equalize voltage and improve frequency characteristics under alternating voltage. Their losses are very low, and after stabilization under DC voltage, they can be considered to have no effect on the voltage division value.

[0068] Table 1

[0069] Rated primary DC voltage 800kV <![CDATA[R1]]> 800MΩ <![CDATA[R2]]> 50kΩ <![CDATA[R3]]> 50kΩ <![CDATA[C1]]> 250pF <![CDATA[C2]]> 4μF <![CDATA[C3]]> 4μF

[0070] like Figure 2 As shown, this embodiment of the invention provides a self-calibration test method for a DC voltage divider, based on the DC voltage divider provided in the foregoing embodiment, including the following steps:

[0071] Step 1: When the DC voltage divider is in normal operating condition, apply a certain DC voltage to its input terminal. After the voltage stabilizes, use a precision meter to test and record the output voltage of the DC voltage divider. Take multiple measurements and average the results to obtain U2. The stabilization time of the output voltage under DC voltage depends on the resistance and capacitance parameters, and generally stabilizes within a few seconds. For convenience, a longer time can be uniformly determined, such as recording data after applying the voltage for 1 minute. Accuracy can be improved by taking multiple measurements and averaging the results. Furthermore, use a precision meter with high resolution and accuracy, such as the Keithley 2001 digital multimeter, which has a 7.5-digit resolution and a basic accuracy of 0.0018%.

[0072] Step 2: Maintain the applied voltage, turn on switch S1 to enter the self-calibration state, and after the voltage stabilizes, use a precision meter to test and record the output voltage of the DC voltage divider. Take multiple measurements and average the values ​​to obtain U2'.

[0073] Step 3: Given the initial value of R1 and the values ​​of R2 and R3, the relative change in the high-voltage arm resistance R1 is calculated using the following formula:

[0074]

[0075] Step 4: Complete the test, close switch S1, and restore the DC voltage divider to normal operating condition.

[0076] Taking the DC voltage divider in Table 1 as an example, given that the initial value of R1 is 800MΩ, and R2 and R3 are both 50kΩ, if a DC voltage of approximately 100kV is applied, the actual voltage will have some deviation. However, the accurate voltage value cannot be directly measured, so we will still calculate using 100kV. In this case, the rated output voltage of the DC voltage divider should be 6.2496V. If R1 deviates by 0.5%, becoming 804MΩ, and a 7.5-digit resolution meter is used for testing, the actual output voltage of the DC voltage divider measured in step 1 will be:

[0077]

[0078] The actual measured output voltage of the DC voltage divider in step 2 is:

[0079]

[0080] The relative change in the high-voltage arm resistance R1 calculated from step 3 is as follows:

[0081] δR1 = 0.42%

[0082] The test results are basically consistent with the actual deviation of 0.5%, indicating that the test method is feasible. Even more accurate results can be obtained by using a higher resolution meter, such as an 8.5-digit resolution meter.

[0083] Embodiments of the present invention also provide another computer device, including a processor and a memory configured to store a computer program capable of running on the processor; wherein, when the processor is configured to run the computer program, it performs the method steps of the foregoing embodiments.

[0084] In practical applications, the aforementioned processors include Field-Programmable Gate Arrays (FPGAs), Central Processing Units (CPUs), or Digital Signal Processors (DSPs). It is understood that for different devices, the electronic devices used to implement the functions of the aforementioned processors can also be other types, and this embodiment of the invention does not impose specific limitations.

[0085] The aforementioned memory can be volatile memory, such as random-access memory (RAM); or non-volatile memory, such as read-only memory (ROM), flash memory, hard disk drive (HDD), or solid-state drive (SSD); or a combination of the above types of memory, and provides instructions and data to the processor.

[0086] In an exemplary embodiment, the present invention also provides a computer-readable storage medium for storing a computer program.

[0087] Optionally, the computer-readable storage medium can be applied to any of the methods in the embodiments of the present invention, and the computer program causes the computer to execute the corresponding processes implemented by the processor in the various methods of the embodiments of the present invention. For the sake of brevity, these will not be described in detail here.

[0088] In the several embodiments provided by this invention, it should be understood that the disclosed devices and methods can be implemented in other ways. The device embodiments described above are merely illustrative. For example, the division of units is only a logical functional division, and in actual implementation, there may be other division methods, such as: multiple units or components can be combined, or integrated into another system, or some features can be ignored or not executed. In addition, the coupling, direct coupling, or communication connection between the various components shown or discussed can be through some interfaces, and the indirect coupling or communication connection between devices or units can be electrical, mechanical, or other forms.

[0089] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code. The solutions in the embodiments of the present invention can be implemented using various computer languages, such as the object-oriented programming language Java and the interpreted scripting language JavaScript.

[0090] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0091] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0092] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0093] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.

[0094] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A test method for a self-calibrating DC voltage divider, wherein the self-calibrating DC voltage divider includes a high-voltage arm and a low-voltage arm connected in series; The high-voltage arm includes a first resistor and a first capacitor, which are connected in parallel. The low-voltage arm includes a first RC unit, a second RC unit, and a switch. One end of the first RC unit is connected to one end of the high-voltage arm, and the other end of the first RC unit is connected to the other end of the second RC unit. The switch is connected in parallel across the two ends of the second RC unit. The first RC unit includes a second resistor and a second capacitor, which are connected in parallel. The second RC unit includes a third resistor and a third capacitor, which are connected in parallel. The input terminals of the DC voltage divider are the other end of the high voltage arm and the other end of the second resistor-capacitor unit in the low voltage arm, and the output terminals of the DC voltage divider are the two ends of the low voltage arm. have ,in, R1, R2, and R3 are the resistance values ​​of the first, second, and third resistors, respectively, and C1, C2, and C3 are the resistance values ​​of the first, second, and third capacitors, respectively. Its features are: When the control switch is closed, a DC voltage is applied to the input terminal of the DC voltage divider to obtain the first output voltage of the DC voltage divider. The control switch is turned on to maintain the aforementioned applied DC voltage and obtain the second output voltage of the DC voltage divider. Calculate the relative change in the first resistance of the high-voltage arm to obtain the resistance value of the first resistance of the high-voltage arm; The calculation of the relative change in the first resistance of the high-voltage arm includes using the following formula to calculate the relative change in the first resistance of the high-voltage arm. : ， Where R1 is the initial resistance value of the first resistor of the high-voltage arm, R2 is the resistance value of the second resistor of the low-voltage arm, and R3 is the resistance value of the third resistor of the low-voltage arm; U2 is the first output voltage of the DC voltage divider, and U2' is the second output voltage of the DC voltage divider.

2. The test method as described in claim 1, characterized in that: Obtaining the first output voltage / second output voltage of the DC voltage divider includes waiting for the output voltage to stabilize, and then taking the average value of the output voltage of the DC voltage divider as the first output voltage / second output voltage.

3. A test apparatus for a self-calibrating DC voltage divider, wherein the self-calibrating DC voltage divider comprises a high-voltage arm and a low-voltage arm connected in series; The high-voltage arm includes a first resistor and a first capacitor, which are connected in parallel. The low-voltage arm includes a first RC unit, a second RC unit, and a switch. One end of the first RC unit is connected to one end of the high-voltage arm, and the other end of the first RC unit is connected to the other end of the second RC unit. The switch is connected in parallel across the two ends of the second RC unit. The first RC unit includes a second resistor and a second capacitor, which are connected in parallel. The second RC unit includes a third resistor and a third capacitor, which are connected in parallel. The input terminals of the DC voltage divider are the other end of the high voltage arm and the other end of the second resistor-capacitor unit in the low voltage arm, and the output terminals of the DC voltage divider are the two ends of the low voltage arm. have ,in, R1, R2, and R3 are the resistance values ​​of the first, second, and third resistors, respectively, and C1, C2, and C3 are the resistance values ​​of the first, second, and third capacitors, respectively. Its features include: The first output voltage acquisition module is configured to acquire the first output voltage of the DC voltage divider when the switch is closed and a DC voltage is applied to the input terminal of the DC voltage divider; The first output voltage acquisition module is configured to acquire the second output voltage of the DC voltage divider when the switch is turned on and a DC voltage is applied to the input terminal of the DC voltage divider; and The resistance change calculation module is configured to calculate the relative change in the first resistance of the high-voltage arm, thereby obtaining the resistance value of the first resistance of the high-voltage arm. The resistance change calculation module calculates the relative change in the first resistance of the high-voltage arm, including by using the following formula to calculate the relative change in the first resistance of the high-voltage arm. : ， Where R1 is the initial resistance value of the first resistor of the high-voltage arm, R2 is the resistance value of the second resistor of the low-voltage arm, and R3 is the resistance value of the third resistor of the low-voltage arm; U2 is the first output voltage of the DC voltage divider, and U2' is the second output voltage of the DC voltage divider.

4. The testing apparatus as described in claim 3, characterized in that: The first output voltage acquisition module acquires the first output voltage of the DC voltage divider by waiting for the output voltage to stabilize and then taking the average value of the output voltage of the DC voltage divider as the first output voltage. The second output voltage acquisition module acquires the second output voltage of the DC voltage divider by waiting for the output voltage to stabilize and then taking the average value of the output voltage of the DC voltage divider as the second output voltage.

5. A computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor; characterized in that: When the processor executes the computer program, it implements the steps of the test method as described in any one of claims 1 to 2.

6. A computer-readable storage medium storing a computer program; characterized in that: When the computer program is executed by a processor, it implements the steps of the test method as described in any one of claims 1 to 2.

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