Measurement system, method and equipment for simulating direct current magnetic bias of converter transformer and medium

Abstract

The invention belongs to the technical field of converter transformer testing, and discloses a measuring system, method, equipment and medium for simulating the direct current magnetic bias of a converter transformer, so as to meet the urgent demand of in-depth research on the direct current magnetic bias phenomenon of the converter transformer. The measuring system comprises a generator, a switch, a boosting transformer, a converter transformer equivalent model and a direct-current constant-current power supply used for controlling direct current passing through the converter transformer model. The generator, the switch, the boosting transformer, the converter transformer equivalent model and the direct-current constant-current power supply are sequentially connected in series to form a test loop; and the measuring device is connected with the test loop. According to the method, the equivalent model of the converter transformer is built by reducing the voltage and the capacity, so that the research cost is remarkably reduced, the key characteristics of the converter transformer under the direct-current magnetic bias effect are maintained, and the accuracy and the reliability of a research result are ensured.

Description

Technical Field

[0001] The invention belongs to the technical field of converter transformer testing, and in particular relates to a measurement system, method, equipment and medium for simulating direct current bias magnetic field of a converter transformer. Background Art

[0002] The converter transformer is an important device in the DC transmission system. In the unipolar DC transmission system, three single-phase transformers are usually combined into a transformer group and the neutral point is grounded, or the neutral point of the three-phase transformer is grounded. When the transformer is in the grounded operation state, it may be affected by DC bias magnetism caused by various factors. For example, the transformer near the DC transmission ground electrode may introduce DC current into the winding through the grounding terminal; in addition, the imbalance of the trigger angle can also cause DC bias magnetism. Under the action of these factors, the magnetization curve of the transformer core becomes asymmetric, and one side may be oversaturated, which will cause a series of problems such as increased excitation current, increased loss, significant vibration and noise, voltage and current distortion, etc., which seriously threaten the stable operation of the transformer. In view of this, it is urgent to use research methods to deeply understand the tolerance of converter transformers to DC bias magnetism to ensure their safe and reliable operation. However, the existing converter transformer products are large in size and extremely expensive. If they are directly used for DC bias magnetism testing, they will not only occupy a huge space, but also cost a lot for a single test, which greatly limits the economic feasibility of DC bias magnetism testing. Summary of the invention

[0003] Based on the above-mentioned shortcomings and deficiencies in the prior art, one of the objects of the present invention is to at least solve one or more of the above-mentioned problems in the prior art. In other words, one of the objects of the present invention is to provide a measurement system, method, equipment and medium for simulating DC bias magnetization of converter transformers that meet one or more of the aforementioned requirements, aiming to achieve economical and efficient DC bias magnetization measurement test of converter transformers.

[0004] In order to achieve the above-mentioned object of the invention, the present invention adopts the following technical solutions: In a first aspect, the present invention provides a measurement system for simulating the DC bias of a converter transformer, comprising a generator, a switch, a step-up transformer, a converter transformer equivalent model, and a DC constant current power supply for controlling the DC current passing through the converter transformer equivalent model; the generator, the switch, the step-up transformer, the converter transformer equivalent model, and the DC constant current power supply are sequentially connected in series to form a test loop; and also includes a measurement device connected to the test loop.

[0005] As a preferred solution, it also includes a capacitor for protecting the DC constant current power supply; the capacitor is connected in parallel with the DC constant current power supply.

[0006] As a preferred solution, the capacity of the converter transformer equivalent model is 2000KVA; the voltage ratio between the AC side and the DC side of the converter transformer equivalent model is (10 / ) kV / 4.4kV; the rated current ratio of the AC side to the DC side of the converter transformer equivalent model is 346.4A / 454.55A; the converter transformer equivalent model includes an iron core, a winding, an oil tank and a cooler; the iron core is configured as a single-phase double-frame four-column structure, including two main columns, two side columns, an upper iron yoke and a lower iron yoke; the cross-sectional areas of the side columns, the upper iron yoke and the lower iron yoke are equal.

[0007] As a preferred solution, the measuring equipment includes a power analyzer, a voltage transformer, a microphone, a vibration sensor and a vibration noise collector; the primary side of the voltage transformer is connected in series to the test loop, and the secondary side is connected to the power analyzer for voltage sampling.

[0008] As a preferred solution, the vibration sensor is fixed on the outer surface of the oil tank; the vibration sensor is configured as a uniaxial acceleration sensor or a triaxial acceleration sensor.

[0009] In a second aspect, the present invention provides a measurement method for simulating DC bias of a converter transformer, based on the measurement system as described in the first aspect, comprising the steps of: establishing a test loop and connecting a measuring device; performing a no-load test based on the test loop to obtain a no-load current; presetting DC bias test data based on the no-load current, the DC bias test data including a DC bias current test point and a corresponding DC bias current; based on each DC bias current in the DC bias test data, simulating DC bias in the test loop in turn to obtain a corresponding measurement value; analyzing each of the measurement values ​​to obtain loss, vibration and noise laws under the influence of different DC bias currents.

[0010] As a preferred scheme, the no-load test is performed based on the test loop to obtain the no-load current, including the steps of: short-circuiting the two ends of the DC constant current in the test loop to disconnect the DC constant current power supply from the test loop; closing the switch in the test loop, and operating the generator to gradually increase the voltage until the rated voltage of the equivalent model of the converter transformer is reached, and measuring the no-load current and no-load loss; operating the generator to gradually reduce the voltage to 0V, and opening the switch to complete the reset.

[0011] As a preferred scheme, based on each DC bias current in the DC bias test data, the test loop is simulated in sequence for DC bias to obtain corresponding measurement values, including the steps of: disconnecting the two terminal connections of the DC constant current in the test loop, so that the DC constant current power supply is connected in series to the test loop; closing the switch in the test loop, and setting the DC constant current to input the DC bias current, operating the generator to gradually increase the voltage to the rated voltage of the converter transformer equivalent model to obtain the corresponding AC / DC superposition current; resetting the DC constant current in the test loop to discharge and eliminate the DC current; operating the generator to gradually reduce the voltage to 0V, and opening the switch to complete the reset.

[0012] In a third aspect, the present invention provides an electronic device, wherein the computer device comprises a memory, a processor and a computer program, and when the computer program is executed by the processor, the measurement method as described in the second aspect is implemented.

[0013] In a fourth aspect, the present invention provides a computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the measurement method as described in the second aspect.

[0014] Compared with the prior art, the present invention has the following beneficial effects: The converter transformer equivalent model was constructed by lowering the voltage and reducing the capacity, so that the performance of the equivalent model could be accurately measured under different DC bias conditions, which not only significantly reduced the research cost, but also maintained the key characteristics of the converter transformer under the DC bias effect, ensuring the accuracy and reliability of the research results.

[0015] Further or more detailed beneficial effects will be described in detail in conjunction with specific examples in the specific implementation manner. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0017] Figure 1 It is a schematic diagram of the structure of the measurement system described in an embodiment of the present invention.

[0018] Figure 2 It is a structural schematic diagram of the equivalent model core of the converter transformer described in an embodiment of the present invention.

[0019] Figure 3It is a flow chart of the measurement method provided by an embodiment of the present invention.

[0020] Figure 4 is a structural diagram of the electronic device provided in an embodiment of the present invention.

[0021] Figure Number: 1. Generator; 2. Step-up transformer; 3. Converter transformer equivalent model; 4. DC constant current power supply; 5. Power analyzer; 6. Capacitor; 7. First voltage transformer; 8. Second voltage transformer; 9. Vibration noise collector; 10. Vibration sensor; 11. Microphone; 12. Switch; 400, electronic device; 401, processor; 402, communication bus; 403, user interface; 404, network interface; 405, memory. DETAILED DESCRIPTION

[0022] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0023] In the following description, multiple embodiments of the present invention are provided, and different embodiments may be replaced or combined, so the present invention may also be considered to include all possible combinations of the same and / or different embodiments described. Therefore, if one embodiment includes features A, B, and C, and another embodiment includes features B and D, then the present invention should also be considered to include embodiments containing one or more of A, B, C, and D, all other possible combinations, even though the embodiment may not be clearly described in the following text.

[0024] The following description provides examples and does not limit the scope, applicability or examples set forth in the claims. Changes may be made to the functions and arrangements of the elements described without departing from the scope of the present invention. Various processes or components may be appropriately omitted, substituted or added to each example. For example, the described method may be performed in an order different from the described order, and various steps may be added, omitted or combined. In addition, the features described in some examples may be combined in other examples.

[0025] In order to facilitate a better understanding of the embodiments of the present invention, before explaining the specific implementation modes of the present invention in detail, its application scenarios are first described.

[0026] The measurement system described in the embodiments of this specification is applied to the performance research process of converter transformers. In these scenarios, the application of the measurement system is to efficiently and cost-effectively test the tolerance of converter transformers under DC bias conditions in a laboratory environment by building a DC bias magnetic measurement system composed of low-voltage, small-capacity transformers in the laboratory. The measurement system described in the embodiments of this specification not only significantly reduces the high cost required for direct field testing of large-scale converter transformer products, but also ensures the accuracy and reliability of the test results, providing strong data support for subsequent performance analysis and optimization strategies. Through this economical and efficient testing method, it is possible to effectively control R&D costs and improve overall economic benefits without sacrificing test quality.

[0027] Embodiment 1: like Figure 1 As shown, this embodiment provides a measurement system for simulating DC bias magnetic field of a converter transformer, comprising a generator 1, a switch 12, a step-up transformer 2, a converter transformer equivalent model 3 and a DC constant current power supply 4 for controlling the DC current passing through the converter transformer equivalent model 3; the generator 1, the switch 12, the step-up transformer 2, the converter transformer equivalent model 3 and the DC constant current power supply 4 are sequentially connected in series to form a test loop; and also includes a measuring device connected to the test loop.

[0028] This embodiment builds the converter transformer equivalent model 3 by reducing the voltage and capacity, which not only significantly reduces the research cost, but also maintains the key characteristics of the converter transformer under the DC bias magnetic effect, ensuring the accuracy and reliability of the research results. Specifically, this embodiment provides a preferred implementation method, the capacity of the converter transformer equivalent model 3 is 2000KVA; the voltage ratio between the AC side and the DC side of the converter transformer equivalent model 3 is (10 / ) kV / 4.4 kV; the rated current ratio of the AC side to the DC side of the converter transformer equivalent model 3 is 346.4A / 454.55A; the converter transformer equivalent model 3 includes an iron core, a winding, an oil tank and a cooler. More specifically, as Figure 2 The core is configured as a single-phase double-frame four-column structure, including two main columns (such as Figure 2 Columns 1 and 2 in the middle), two side columns (such as Figure 2Column 3 and column 4 in the middle), an upper iron yoke and a lower iron yoke; the cross-sectional areas of the side column, the upper iron yoke and the lower iron yoke are equal. This structure is consistent with the core structure of large converter transformer products and can truly reflect the magnetic characteristics of the product. More specifically, the cooler of the converter transformer equivalent model 3 is realized by a plate-type radiator. This design not only has high heat dissipation efficiency, but is also suitable for small transformers. The plate-type radiator is far away from the oil tank, so that there is sufficient construction and operation space outside the oil tank, which is convenient for maintenance and overhaul or adding external test measures for the oil tank.

[0029] Specifically, the present embodiment provides a preferred implementation, further comprising a capacitor 6 for protecting the DC constant current power supply 4. The capacitor 6 is connected in parallel with the DC constant current power supply 4, and can play a role in filtering and stabilizing the current in the circuit, effectively preventing damage to the DC constant current power supply caused by current fluctuations or instantaneous overloads, thereby improving the stability and safety of the entire measurement system. It is understandable that the DC constant current power supply 4 outputs a constant DC current, and the output voltage between the two output terminals is lower than 24V, and the voltage requirements of the capacitors connected in parallel are not high. More specifically, different capacitor groups can be selected in series and parallel according to the AC amplification effect generated by the different DC currents required, so that the AC current passed by the DC constant current power supply during the final test is less than 3Arms to ensure the safe operation of the DC constant current power supply.

[0030] Specifically, this embodiment provides a preferred implementation method, wherein the measuring device includes a power analyzer 5, a voltage transformer, a microphone 11, a vibration sensor 10, and a vibration noise collector 9. The power analyzer 5 is connected in parallel with the voltage of the test loop and in series with the current, and is used to accurately measure and record key parameters such as power, current, and voltage in the test loop. Figure 1 As shown, the voltage transformer can be set to two, including a first voltage transformer 7 and a second voltage transformer 8, which are used to monitor voltage changes with high precision. The primary side is connected in series to the test loop, and the secondary side is connected to the power analyzer for voltage sampling to ensure the accuracy of the test data. It can be understood that since the rated voltage on the high-voltage side of the converter transformer equivalent model 3 is 5773V and the rated voltage on the low-voltage side is 4400V, the voltage is relatively high and can be connected to the voltage measurement port of the power analyzer after a high-precision voltage transformer. The power analyzer 5 can directly read the voltage, loop current, and no-load loss (including the loss caused by DC bias magnetic distortion). More specifically, in order to ensure the safety of the power analyzer, the power analyzer 5 is arranged near the ground, that is, in front of the DC constant current power supply in this embodiment.

[0031] Specifically, this embodiment provides a preferred implementation method, in which the vibration sensor 10 is fixed on the outer surface of the fuel tank. The vibration sensor 10 is configured as a uniaxial acceleration sensor or a triaxial acceleration sensor, which can record vibration acceleration signals in a single direction or three directions respectively. Through the integral processing of computer post-processing software, these acceleration data can be further converted into velocity and displacement information. At the same time, spectrum analysis of these three sets of data is helpful to summarize and discover vibration patterns. More specifically, according to measurement needs, the microphone 11 can be accurately fixed at a position of half the height of the fuel tank and maintained at a distance of 0.3 meters or 1 meter from the outer edge of the fuel tank. The noise signal is captured by the microphone and transmitted to the vibration noise collector 9, and then the soundprint analysis is performed using computer software to accurately obtain key information such as the amplitude and spectrum of the noise.

[0032] Embodiment 2: like Figure 3 As shown, this embodiment provides a method for measuring the DC bias of a simulated converter transformer, based on the measurement system as described in the first aspect, including the steps of: establishing a test loop and connecting a measuring device; performing a no-load test based on the test loop to obtain a no-load current; presetting DC bias test data based on the no-load current, the DC bias test data including a DC bias current test point and a corresponding DC bias current; based on each DC bias current in the DC bias test data, simulating DC bias in the test loop in turn to obtain a corresponding measurement value; analyzing each of the measurement values ​​to obtain the loss, vibration and noise laws under the influence of different DC bias currents. More specifically, the DC bias current test point can be set to 25%, 50%, 75%, 100%, 150%, 200%, 250%, and the DC bias current can be set to 2.2A, 4.4A, 6.5A, 8.7A, 13.1A, 17.5A, 21.8A.

[0033] Specifically, this embodiment provides a preferred implementation method, in which a no-load test is performed based on the test circuit to obtain a no-load current, including the steps of: short-circuiting the two ends of the DC constant current in the test circuit to disconnect the DC constant current power supply from the test circuit; closing the switch in the test circuit, and operating the generator to gradually increase the voltage until the rated voltage of the equivalent model of the converter transformer is reached, and measuring the no-load current and no-load loss; operating the generator to gradually reduce the voltage to 0V, and opening the switch to complete the reset.

[0034] Specifically, this embodiment provides a preferred implementation method, which is based on each DC bias current in the DC bias test data, and simulates DC bias in the test loop in sequence to obtain corresponding measurement values, including the steps of: disconnecting the two end terminals of the DC constant current in the test loop, so that the DC constant current power supply is connected in series to the test loop; closing the switch in the test loop, and setting the DC constant current to input the DC bias current, operating the generator to gradually increase the voltage to the rated voltage of the converter transformer equivalent model to obtain the corresponding AC / DC superposition current; resetting the DC constant current in the test loop to discharge and eliminate the DC current; operating the generator to gradually reduce the voltage to 0V, and opening the switch to complete the reset.

[0035] Embodiment three: like Figure 4 As shown, this embodiment provides an electronic device, which may include: at least one processor, at least one network interface, a user interface, a memory, and at least one communication bus.

[0036] The communication bus can be used to realize the connection and communication among the above-mentioned components.

[0037] The user interface may include buttons, and the optional user interface may also include a standard wired interface or a wireless interface.

[0038] The network interface may include but is not limited to a Bluetooth module, an NFC module, a Wi-Fi module, etc.

[0039] Among them, the processor may include one or more processing cores. The processor uses various interfaces and lines to connect the various parts of the entire electronic device, and executes various functions of the electronic device and processes data by running or executing instructions, programs, code sets or instruction sets stored in the memory, and calling data stored in the memory. Optionally, the processor can be implemented in at least one hardware form of DSP, FPGA, and PLA. The processor can integrate one or a combination of CPU, GPU, modem, etc. Among them, the CPU mainly processes the operating system, user interface, and application programs; the GPU is responsible for rendering and drawing the content to be displayed on the display; the modem is used to handle wireless communications. It can be understood that the above-mentioned modem may not be integrated into the processor, but may be implemented separately through a chip.

[0040] Among them, the memory may include RAM or ROM. Optionally, the memory includes a non-transitory computer-readable medium. The memory can be used to store instructions, programs, codes, code sets or instruction sets. The memory may include a program storage area and a data storage area, wherein the program storage area may store instructions for implementing an operating system, instructions for at least one function (such as a touch function, a sound playback function, an image playback function, etc.), instructions for implementing the above-mentioned various method embodiments, etc.; the data storage area may store data involved in the above-mentioned various method embodiments, etc. The memory may also be at least one storage device located away from the aforementioned processor. The memory as a computer storage medium may include an operating system, a network communication module, a user interface module and a measurement application. The processor may be used to call the measurement application stored in the memory and execute the measurement steps mentioned in the above-mentioned embodiments.

[0041] Embodiment 4: This embodiment provides a computer-readable storage medium, which stores instructions. When the computer-readable storage medium is executed on a computer or a processor, the computer or the processor executes the above-mentioned Figure 3 One or more steps in the illustrated embodiment. If the components of the electronic device described above are implemented in the form of software functional units and sold or used as independent products, they can be stored in the computer-readable storage medium.

[0042] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware or any combination thereof. When implemented by software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the process or function described in the embodiment of this specification is generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted through the computer-readable storage medium. The computer instructions can be transmitted from a website site, computer, server or data center to another website site, computer, server or data center by wired (e.g., coaxial cable, optical fiber, digital subscriber line (Digital Subscriber Line, DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) mode. The computer-readable storage medium can be any available medium that can be accessed by a computer or a data storage device such as a server or data center that includes one or more available media integrated. The available medium may be a magnetic medium (eg, a floppy disk, a hard disk, a magnetic tape), an optical medium (eg, a digital versatile disc (DVD)), or a semiconductor medium (eg, a solid state drive (SSD)).

[0043] Those skilled in the art can understand that all or part of the process in the method of the above-mentioned embodiment 2 can be completed by instructing the relevant hardware through a computer program, and the program can be stored in a computer-readable storage medium. When the program is executed, it can include the process of the embodiments of the above-mentioned methods. The aforementioned storage medium includes: ROM, RAM, magnetic disk or optical disk and other media that can store program codes. In the absence of conflict, the technical features in this embodiment and the implementation scheme can be combined arbitrarily.

[0044] It should be noted that, for the above-mentioned method embodiments, for the sake of simplicity, they are all described as a series of action combinations, but those skilled in the art should know that the present invention is not limited by the described action sequence, because according to the present invention, certain steps can be performed in other sequences or simultaneously. Secondly, those skilled in the art should also know that the embodiments described in the specification are all preferred embodiments, and the actions and modules involved are not necessarily required by the present invention.

[0045] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0046] The above is only an exemplary embodiment of the present invention and cannot be used to limit the scope of the present invention. That is, any equivalent changes and modifications made according to the teachings of the present invention are still within the scope of the present invention. After considering the specification and practicing the disclosure here, it will be easy for those skilled in the art to think of the implementation scheme of the present invention. The present invention is intended to cover any modification, use or adaptation of the present invention, which follows the general principles of the present invention and includes common knowledge or customary technical means in the art that are not recorded in the present invention. The description and examples are only regarded as exemplary, and the scope and spirit of the present invention are defined by the claims.

Claims

1. A measurement system for simulating DC bias magnetic field of converter transformer, characterized in that: It includes a generator, a switch, a step-up transformer, an equivalent model of a converter transformer, and a DC constant current power supply for controlling a DC current passing through the equivalent model of the converter transformer; The generator, the switch, the step-up transformer, the converter transformer equivalent model and the DC constant current power supply are connected in series in sequence to form a test loop; Also included is a measuring device connected to the test loop.

2. A measurement system for simulating DC bias magnetic field of a converter transformer according to claim 1, characterized in that: Also includes a capacitor for protecting the DC constant current power supply; The capacitor is connected in parallel with the DC constant current power supply.

3. A measurement system for simulating DC bias magnetic field of converter transformer according to claim 2, characterized in that: The equivalent model capacity of the converter transformer is 2000KVA; The voltage ratio between the AC side and the DC side of the converter transformer equivalent model is (10 / )kV / 4.4kV; The rated current ratio of the AC side to the DC side of the converter transformer equivalent model is 346.4A / 454.55A; The converter transformer equivalent model includes an iron core, a winding, an oil tank and a cooler; The iron core is configured as a single-phase double-frame four-column structure, including two main columns, two side columns, an upper iron yoke and a lower iron yoke; The cross-sectional areas of the side pillar, the upper iron yoke and the lower iron yoke are equal.

4. A measurement system for simulating DC bias magnetic field of converter transformer according to claim 3, characterized in that: The measuring equipment includes a power analyzer, a voltage transformer, a microphone, a vibration sensor and a vibration noise collector; The voltage transformer is connected in series with the test loop on its primary side, and connected to the power analyzer on its secondary side for voltage sampling.

5. A measurement system for simulating DC bias magnetic field of converter transformer according to claim 4, characterized in that: The vibration sensor is fixed to the outer surface of the oil tank; The vibration sensor is configured as a uniaxial acceleration sensor or a triaxial acceleration sensor.

6. A method for measuring the DC bias magnetic field of a simulated converter transformer, characterized in that: Based on the measurement system according to any one of claims 1 to 5, comprising the steps of: Establish test loops and connect measuring equipment; Perform a no-load test based on the test circuit to obtain a no-load current; Based on the no-load current, preset DC bias magnetic test data, the DC bias magnetic test data includes a DC bias magnetic current test point and a corresponding DC bias magnetic current; Based on each DC bias current in the DC bias test data, simulating DC bias in the test loop in turn to obtain a corresponding measurement value; The measured values ​​are analyzed to obtain the loss, vibration and noise patterns under the influence of different DC bias currents.

7. A method for measuring the DC bias magnetic field of a simulated converter transformer according to claim 6, characterized in that: The no-load test is performed based on the test circuit to obtain the no-load current, comprising the steps of: Short-circuit the two ends of the DC constant current in the test loop to disconnect the DC constant current power supply from the test loop; Closing the switch in the test circuit, and operating the generator to gradually increase the voltage until the voltage reaches the rated voltage of the converter transformer equivalent model, and measuring the no-load current; Operate the generator to gradually reduce the voltage to 0V and open the switch to complete the reset.

8. The method for measuring the DC bias magnetic field of a simulated converter transformer according to claim 7, characterized in that: The method of simulating DC bias magnetization in sequence for the test loop based on each DC bias magnetization current in the DC bias magnetization test data to obtain a corresponding measurement value comprises the following steps: Disconnect the two terminal ends of the DC constant current in the test loop, so that the DC constant current power supply is connected in series to the test loop; The switch in the test loop is closed, and the DC constant current is set to input the DC bias current, and the generator is operated to gradually increase the voltage to the rated voltage of the converter transformer equivalent model to obtain the corresponding AC / DC superposition current; Resetting the DC constant current in the test loop to discharge and eliminate the DC current; Operate the generator to gradually reduce the voltage to 0V and open the switch to complete the reset.

9. A computer device, comprising a memory, a processor and a computer program, characterized in that: When the computer program is executed by a processor, the measuring method according to any one of claims 6 to 8 is implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the measuring method according to any one of claims 6 to 8 is implemented.

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