Method and system for automatically checking vehicle-mounted current load box of metering test vehicle

Abstract

The invention relates to a method for automatically checking a vehicle-mounted current load box of a metering test vehicle, which is used for checking the tested vehicle-mounted current load box and comprises the following steps of: when the tested vehicle-mounted current load box is in a vehicle-mounted state, short-circuiting the tested vehicle-mounted current load box; the common secondary load of the secondary line of the tested vehicle-mounted current load box and the vehicle-mounted line is measured; switching the tested vehicle-mounted current load box to a working gear, and measuring the common overall load of the tested vehicle-mounted current load box body, the secondary line and the vehicle-mounted line; calculating the body load of the tested vehicle-mounted current load box according to the overall load and the secondary load; and verifying the body load of the tested vehicle-mounted current load box. According to the method, the vehicle-mounted current load box does not need to be removed and then sent to a laboratory for verification, the load box can be directly verified in a vehicle-mounted state, the parameters of the vehicle-mounted current load box in a real working scene state can be accurately verified, and the verification accuracy is more excellent.

Description

Technical Field

[0001] The present invention belongs to the technical field of transformer testing, and particularly relates to an automatic calibration method and system for an on-vehicle current load box of a metering test vehicle. Background Art

[0002] According to the requirements of the "Electric Current Transformer Verification Regulation JJG1189.3", current transformers need to be verified or calibrated on-site. To solve the problems of transportation, handling, and stacking of verification equipment, testing institutions have adopted metering test vehicles. The test vehicle combines transformer verification equipment with a vehicle, serving both as a transportation tool and a verification device. The on-vehicle equipment includes a standard current transformer, a calibrator, a current load box, and a current boosting power supply device, etc.

[0003] According to the requirements of the "Transformer Load Box Calibration Specification" JJF1264-2010, current transformer load boxes need to be calibrated annually to ensure that the verification equipment meets the calibration standards. This specification stipulates that the accuracy level of the load box for current transformer verification should not be lower than level 3. Usually, the calibration of the load box is carried out in a laboratory, and since the load equivalent impedance of the current load box is small, the impedance of the external wire should generally be controlled within 0.06 Ω (or 0.05 Ω). After deducting the external wire resistance, it is verified whether the load of the calibrated load box meets the requirements of the accuracy level.

[0004] However, when the current load box on the metering test vehicle is designed, the verification equipment is integrated with the vehicle, and for the realization of automatic detection and on-vehicle wiring, the impedance of the external circuit of the loop may exceed the specified value. This will cause the actual load of the secondary loop to exceed the specified requirements, thereby affecting the accuracy and reliability of the verification data of the current transformer during subsequent use.

[0005] Currently, for the calibration method of the on-vehicle current load box of the metering test vehicle, it is only possible to verify the accuracy of the load box body by removing it and performing laboratory calibration, but it does not fully prove that the load of all loops meets the test requirements. Because based on the above structural characteristics, when the current transformer load box is calibrated separately in the laboratory, since the test loop is short, although the calibration can be ensured to be qualified, this calibration mainly verifies the accuracy of the load box itself and does not consider the influence of the external loop. When calibrating on the metering test vehicle, due to the complex on-vehicle wiring and the large influence of the external leads, the actual load may not meet the standard.

[0006] Therefore, a convenient method is needed that can solve the interference of the external leads and can calibrate both the body of the on-vehicle current load box and the load of the secondary loop, so as to ensure that the actual load value meets the requirements of transformer verification. Summary of the Invention Based on the above-mentioned drawbacks and deficiencies existing in the prior art, one of the objectives of the present invention is to at least solve one or more of the above-mentioned problems existing in the prior art, or provide an automatic calibration method and system for the on-vehicle current load box of a metering test vehicle that meet one or more of the foregoing requirements.

[0007] To achieve the above-mentioned invention objective, the present invention adopts the following technical solutions: In a first aspect, the present invention provides an automatic calibration method for the on-vehicle current load box of a metering test vehicle, which is used to calibrate the on-vehicle current load box under test, and includes: When the on-vehicle current load box under test is in the on-vehicle state, applying a test signal to the on-vehicle current load box under test, short-circuiting the on-vehicle current load box under test, and measuring the secondary load common to the secondary circuit and the on-vehicle circuit of the on-vehicle current load box under test; Switching the on-vehicle current load box under test to the working gear position, and measuring the overall load common to the body, secondary circuit and on-vehicle circuit of the on-vehicle current load box under test; Calculating the body load of the on-vehicle current load box under test based on the overall load and the secondary load; Calibrating the body load of the on-vehicle current load box under test.

[0008] As a preferred implementation manner, the method further includes: Judging whether the secondary load common to the secondary circuit and the external circuit of the on-vehicle current load box under test meets the specified range of the regulations, and when it does not meet the specified range of the regulations, reminding the user to correct the load of the secondary circuit of the on-vehicle current load box under test.

[0009] As a preferred implementation manner, the method further includes: Providing the user with a modification suggestion for the secondary circuit according to the difference between the secondary load common to the secondary circuit and the external circuit of the on-vehicle current load box under test and the specified range of the regulations.

[0010] As a preferred implementation manner, the calibration includes: Calculating the resistance, inductive reactance, and power factor of the on-vehicle current load box under test based on the body load of the on-vehicle current load box under test, and calibrating the resistance, inductive reactance, and power data.

[0011] As a preferred implementation manner, the method further includes: judging whether the resistance and inductance of the on-vehicle current load box under test need to be corrected according to the resistance, inductive reactance, and power data, and when the resistance and inductance of the on-vehicle current load box under test need to be corrected, calculating the correction values required for the resistance and inductance.

[0012] On the other hand, the present invention also provides an automatic calibration system for an on-vehicle current load box of a metering test vehicle, which applies the automatic calibration method for the on-vehicle current load box of the metering test vehicle as described in any one of the above, and is used to calibrate the on-vehicle current load box under test, including a current output port, a current source, a voltage measurement port, and a control terminal; The current source is electrically connected to the current output port, and the control terminal is electrically connected to the voltage measurement port and the current source; the control terminal is used to control the current source to output a specified current to the current output port, so as to apply a test signal to the on-vehicle current load box under test, measure the combined secondary load of the secondary circuit and the on-vehicle circuit of the on-vehicle current load box under test, and measure the overall load of the body, secondary circuit and on-vehicle circuit of the on-vehicle current load box under test; and calculate the body load of the on-vehicle current load box under test based on the overall load and the secondary load, and calibrate the body load of the on-vehicle current load box under test.

[0013] As a preferred embodiment, the control terminal is further used to determine whether the combined secondary load of the secondary circuit and the external circuit of the on-vehicle current load box under test meets the specified range of the regulations. When it does not meet the specified range of the regulations, the user is reminded to correct the load of the secondary circuit of the on-vehicle current load box under test.

[0014] As a preferred embodiment, the control terminal is further used to provide a modification suggestion for the secondary circuit to the user based on the difference between the combined secondary load of the secondary circuit and the external circuit of the on-vehicle current load box under test and the specified range of the regulations.

[0015] As a preferred embodiment, the calibration includes: Calculate the resistance, inductive reactance, and power factor of the on-vehicle current load box under test based on the body load of the on-vehicle current load box under test, and calibrate the resistance, inductive reactance, and power data.

[0016] As a preferred embodiment, the control terminal is further used to determine whether the resistance and inductance of the on-vehicle current load box under test need to be corrected based on the resistance, inductive reactance, and power data. And when the resistance and inductance of the on-vehicle current load box under test need to be corrected, calculate the correction values required for the resistance and inductance.

[0017] Compared with the prior art, the beneficial effects of the present invention are: For the automatic calibration method and system of the on-vehicle current load box of the present invention, it is not necessary to remove the on-vehicle current load box and then send it to the laboratory for calibration. The load box can be directly calibrated in the on-vehicle state. At the same time, for the automatic calibration method and system of the on-vehicle current load box of the present invention, the calibration environment is consistent with the secondary circuit and external circuit conditions of the on-vehicle current load box in the real working scenario, and it can accurately calibrate the parameters of the on-vehicle current load box in the real working scenario state, with better calibration accuracy, ensuring that the mutual inductor calibration data is more accurate and reliable. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic structural diagram of a metering test vehicle carrying a current load box; Figure 2 It is a schematic connection structure diagram of the metering test vehicle when calibrating a power current transformer; Figure 3 It is a schematic connection diagram of the system according to an embodiment of the present application with a tested current load box during calibration. Detailed implementation manners Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application.

[0019] Next, the specific implementation manners of the present invention will be specifically described with reference to the accompanying drawings. The following description with reference to the accompanying drawings is provided to assist in understanding the exemplary embodiments of the present invention defined by the claims and their equivalents. It includes various specific details for assistance in understanding, but they are only to be regarded as exemplary. Therefore, those skilled in the art will recognize that various changes and modifications can be made to the embodiments described herein without departing from the scope and spirit of the present invention. Moreover, in order to make the description of the specification more clear and concise, the detailed descriptions of well-known functions and structures in the art will be omitted.

[0020] For the convenience of understanding the present invention, before elaborating in detail on the on-vehicle current load box automatic calibration method and system of the present invention in combination with one or more embodiments, a brief description will first be given of the existing metering test vehicle and its connection structure with the calibrated transformer.

[0021] See Figure 1 , Figure 1 shown is a schematic structural diagram of a metering test vehicle carrying a current load box. All calibration equipment is integrated in a vehicle, including a voltage regulating power supply, a current boosting power supply, a reactive power compensation capacitor, a standard current transformer, a transformer calibrator, and a current transformer load box for current transformer calibration. On the vehicle body panel, there are primary connection terminals P1, P2 and L1, L2, and secondary connection terminals S1, S2 and K1, K2 for connecting an externally tested current transformer.

[0022] See Figure 2 , Figure 2 shown is a schematic connection structure diagram of the metering test vehicle when calibrating a power current transformer. The calibration process uses the analog comparison method in accordance with the regulation JJG1189.3 for measurement. Figure 2 In [reference], S1 and S2 are secondary connection terminals for connecting a tested current transformer outside the metering test vehicle, and the Tx connection terminal is used to connect to the on-vehicle current load box automatic calibration system of the present invention. Figure 2Wire a is the connecting wire from the secondary terminal block to the terminal of the current transformer under test outside the metering test vehicle, while wire b is the secondary connecting wire of the calibration circuit inside the metering test vehicle.

[0023] In the above connection structure, the calibration equipment is integrated with the vehicle. And for realizing automatic detection and in-vehicle wiring, the impedance of the external circuit of the loop may exceed the specified value. This will cause the actual load of the secondary loop to exceed the specified requirements when calibrating the in-vehicle current load box, thereby affecting the accuracy and reliability of the calibration data of the current transformer during subsequent use.

[0024] The present invention provides an automatic calibration method for an in-vehicle current load box of a metering test vehicle, which specifically includes the following steps: S1. When the current load box under test is in the in-vehicle state, apply a test signal to the current load box under test.

[0025] Specifically, in step S1, when the current load box under test is in the in-vehicle state, connect it to the calibration device of the metering test vehicle. At this time, apply a test signal to the current load box under test through the calibration device. The test signal can be an AC constant current signal. For example, a current with adjustable amplitude and power frequency.

[0026] S2. Short-circuit the current load box under test and measure the common secondary load of the secondary circuit of the current load box under test and the in-vehicle circuit.

[0027] In step S2, switch the current load box under test to the short-circuit state or short-circuit gear. While applying the test signal, measure the voltage at the connection point of the current load box under test. Based on the applied current signal and the measured voltage signal, calculate the common secondary load Zc of the secondary circuit of the current load box under test and the in-vehicle circuit. The secondary load Zc is usually expressed in the form of complex impedance, including a resistance component and a reactance component, that is, Zc = Rc + jXc.

[0028] In step S2, the measurement point is located at the connection of the current load box under test and the in-vehicle secondary circuit, or is connected to this connection point through the external terminal of the metering test vehicle. When the current load box under test is in the short-circuit state, the test signal flows through the in-vehicle secondary circuit and the secondary circuit of the current load box under test, but does not flow through the body of the current load box under test. Therefore, the load measured at this time mainly reflects the impedance of the secondary circuit and the in-vehicle circuit.

[0029] S3. Switch the current load box under test to the working gear and measure the overall load of the body, secondary circuit and in-vehicle circuit of the current load box under test; Step S3 switches the tested on-vehicle current load box to a certain working gear to be calibrated. The working gear refers to a specific setting gear of the tested on-vehicle current load box for simulating different secondary loads of current transformers. A test signal is applied to the tested on-vehicle current load box through a calibration device. The type and parameters of the test signal can be the same as or different from those in Step S2. Usually, it is also an AC constant current signal.

[0030] While applying the test signal, measure the voltage at the connection point of the tested on-vehicle current load box. Based on the applied current signal and the measured voltage signal, calculate the overall load Zz of the body, secondary circuit, and on-vehicle circuit of the tested on-vehicle current load box together.

[0031] This overall load Zz is usually also expressed in the form of complex impedance, i.e., Zz = Rz + jXz. At the working gear, the test signal flows through the body, secondary circuit, and on-vehicle circuit of the tested on-vehicle current load box. Therefore, the measured load at this time is the series total impedance of all these parts.

[0032] S4. Calculate the body load of the tested on-vehicle current load box based on the overall load and the secondary load.

[0033] Based on the overall load Zz measured in Step S3 and the secondary load Zc measured in Step S2, calculate the body load Zb of the tested on-vehicle current load box. Since the overall load Zz is the series superposition of the body load Zb and the secondary load Zc, the body load Zb can be obtained by subtracting complex impedances: Zb = Zz - Zc = (Rz - Rc) + j(Xz - Xc).

[0034] In this way, the true load characteristics of the body of the tested on-vehicle current load box in its on-vehicle environment can be effectively separated, and the influence of the on-vehicle secondary circuit impedance is eliminated.

[0035] S5. Calibrate the body load of the tested on-vehicle current load box.

[0036] Specifically, the calibration can include calculating the resistance, inductive reactance, and power data of the tested on-vehicle current load box at this working gear based on the body load Zb. For example, according to calculate the resistance Rb, inductive reactance Xb, and further calculate the apparent power S = I * 2 |Zb|, active power P = I 2 Rb, reactive power Q = I 2 Xb, and through the formula Obtain the power factor, where I is the effective value of the applied test current. Then, verify whether the resistance, inductive reactance, and power data meet the preset requirements or the allowable range specified by the standard. These preset requirements or standard-specified ranges can be stored in the memory of the verification device.

[0037] According to the automatic verification method of the on-vehicle current load box of the metering test vehicle in the above steps, the present invention can directly perform verification while the on-vehicle current load box under test remains in the on-vehicle state, without removing it from the vehicle and sending it to the laboratory, greatly improving the verification efficiency and reducing the workload.

[0038] In addition, the method of the present invention has high environmental consistency and high verification accuracy. When performing verification in the on-vehicle state, the secondary circuit and external circuit conditions are exactly the same as the connection of the load box in the real working scenario. By measuring the secondary load in the short-circuit state and separating it from the overall load, the load of the load box body that is not affected by the external circuit can be accurately obtained, thereby eliminating the influence of the secondary circuit impedance differences such as the design principles of different manufacturers, cable layouts, and wire diameters on the verification results, and ensuring the accuracy and reliability of the verification results.

[0039] At the same time, this method has a high degree of automation and high efficiency, reduces the manual operations required for disassembly, and can complete most steps through an automated process, improving the verification speed and efficiency.

[0040] Based on the above method embodiments, other embodiments of the present invention may further include the following steps to provide more comprehensive verification and diagnosis functions: S601. Judge whether the secondary load common to the secondary circuit and the external circuit of the on-vehicle current load box under test meets the range specified by the regulations. When it does not meet the range specified by the regulations, remind the user to correct the load of the secondary circuit of the on-vehicle current load box under test.

[0041] After measuring the secondary load Zc common to the secondary circuit and the on-vehicle circuit of the on-vehicle current load box under test through steps S1 - S5, judge whether the secondary load Zc meets the range specified by the regulations. The above range specified by the regulations is the upper limit value set by the industry standard or relevant specifications for the total impedance of the secondary circuit. For example, for some applications, it may be required that the total secondary impedance is less than 0.06 Ω. In addition, this judgment can also be based on the modulus value of the secondary load Zc or its resistance / inductive reactance components.

[0042] S602. Provide the user with suggestions for modifying the secondary circuit according to the difference between the secondary load common to the secondary circuit and the external circuit of the on-vehicle current load box under test and the range specified by the regulations.

[0043] The above modification suggestions can be stored in the calibration device and provided according to the out-of-tolerance situation of Zc. For example, if the resistance component of Zc is too large, it is recommended to check the contacts, increase the wire diameter or reduce the line length; if the inductive reactance component of Zc is too large, it is recommended to check the line layout, etc. Warnings and suggestions can be given through a display screen, sound or other user interface means.

[0044] S603. Determine whether the resistance and inductance of the measured on-vehicle current load box need to be corrected according to the resistance, inductive reactance, and power data, and calculate the correction values required for the resistance and inductance when the resistance and inductance of the measured on-vehicle current load box need to be corrected.

[0045] After steps S1 - S5 complete the calibration of the body load Zb of the measured on-vehicle current load box and determine whether it meets the preset requirements according to the calculated resistance, inductive reactance, and power data of the body load, if it is judged as unqualified, it can be further determined whether the resistance and inductance components of the measured on-vehicle current load box need to be corrected according to the resistance, inductive reactance, and power data through step S603.

[0046] When correction is needed, calculate the correction values required for the resistance and inductance. The correction values can indicate that the parameters of the resistance or inductance components need to be adjusted inside the body load box to meet the specified requirements. The judgment and calculation of the correction values can be based on the stored design parameters and measured values of the load box, and the prompt for the need for correction and the suggestions for the correction values can also be given through the user interface.

[0047] Another embodiment of the present invention also provides an automatic calibration system for the on-vehicle current load box of a metering test vehicle, which applies the automatic calibration method for the on-vehicle current load box of a metering test vehicle as described in any one of the above to calibrate the measured on-vehicle current load box.

[0048] The system includes a current output port, a current source, a voltage measurement port, and a control terminal. Among them, the current source is electrically connected to the current output port, and the control terminal is electrically connected to the voltage measurement port and the current source; the control terminal is used to control the current source to output a specified current to the current output port to measure the secondary load shared by the secondary circuit and the on-vehicle circuit of the measured on-vehicle current load box, and measure the overall load of the body, secondary circuit, and on-vehicle circuit of the measured on-vehicle current load box; and calculate the body load of the measured on-vehicle current load box according to the overall load and the secondary load, and calibrate the body load of the measured on-vehicle current load box.

[0049] The schematic diagram of the connection of the system during calibration with the measured current load box is as Figure 3As shown, the current output port is connected to the secondary terminal S2 originally used to connect the current transformer under test on the metering test vehicle body, and the voltage measurement port is connected to the Tx terminal. After the connection is completed, the control terminal controls the current source to output the corresponding current according to the test requirements, and obtains data through the Tx terminal, so as to measure by the four-terminal method, that is, the output current port outputs I* and I, and the voltage measurement port collects U* and U. Through the formula , the impedance Z of the loop under test is obtained. Through the formula , the resistance and inductive reactance of the loop are obtained, and through the formula , parameters such as the power factor are obtained.

[0050] After the system of this embodiment measures the combined secondary load of the secondary circuit and the external circuit of the current load box on the vehicle under test at its control terminal, it judges whether it meets the specified range of the regulations. If it exceeds the specified range of the regulations, the user is prompted to adjust the secondary circuit load.

[0051] In an improved embodiment, the above control terminal can also provide the user with modification suggestions for the secondary circuit according to the difference between the combined secondary load of the secondary circuit and the external circuit of the current load box on the vehicle under test and the specified range of the regulations. The prompted modification suggestions are not limited to methods that can reduce the load, such as increasing the wire diameter and reducing the line length.

[0052] In addition, after the control terminal of this embodiment outputs the calibration result of the current load box on the vehicle under test, the resistance, inductive reactance, and power data obtained therefrom, it judges whether the resistance and inductance of the current load box on the vehicle under test need to be corrected according to the above data, and issues a correction prompt to the user, and realizes the correction of the unqualified current load box after calibration.

[0053] The automatic calibration system of the current load box on the vehicle of the metering test vehicle of this embodiment does not need to remove the current load box on the vehicle and then send it to the laboratory for calibration. It can directly calibrate the load box in the on-vehicle state. At the same time, the automatic calibration system of the current load box on the vehicle of the present invention has the same secondary circuit and external circuit conditions as those of the current load box in the real working scenario during calibration. There is no need to additionally consider the influence of the secondary circuit impedance such as the design principle of different manufacturers, cable layout, and wire diameter size during the test process, and it can accurately calibrate the parameters of the current load box on the vehicle in the real working scenario state, with better calibration accuracy, ensuring that the mutual inductor calibration data is more accurate and reliable.

[0054] Those of ordinary skill in the art can realize that the units and algorithm steps of each example described in combination with the embodiments disclosed herein can be implemented by electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are executed in a hardware or software manner depends on the specific application and design constraints of the technical solution. A professional technician can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of the present invention.

[0055] As described above, the above are only exemplary embodiments of the present disclosure, and the scope of the present disclosure cannot be limited thereby. That is, any equivalent changes and modifications made in accordance with the teachings of the present disclosure still fall within the scope covered by the present disclosure. After considering the specification and practicing the present disclosure herein, those skilled in the art will readily think of other embodiments of the present disclosure. This application aims to cover any variations, uses, or adaptations of the present disclosure, which follow the general principles of the present disclosure and include common general knowledge or conventional technical means in the technical field not recorded in the present disclosure. The specification and embodiments are only regarded as exemplary, and the scope and spirit of the present disclosure are defined by the claims.

Claims

1. A method for automatically calibrating an on-board current load box of a metrological test vehicle, used for calibrating the on-board current load box under test, characterized in that: include: When the on-board current load box under test is in a vehicle-mounted state, applying a test signal to the on-board current load box under test, short-circuiting the on-board current load box under test, and measuring the secondary circuit of the on-board current load box under test and the secondary load of the on-board circuit; Switching the on-board current load box under test to the working position, measuring the overall load of the main body, secondary circuit and on-board circuit of the on-board current load box under test; Calculate the main load of the tested vehicle-mounted current load box according to the overall load and the secondary load; The main body load of the tested vehicle-mounted current load box is verified.

2. The method for automatically calibrating the on-board current load box of a metrological test vehicle according to claim 1, characterized in that: The method also includes: Determine whether the secondary load of the secondary circuit of the tested vehicle current load box and the external circuit meets the specified range of the regulations. When it does not meet the specified range of the regulations, remind the user to correct the load of the secondary circuit of the tested vehicle current load box.

3. The method for automatically calibrating the on-board current load box of a metrological test vehicle as claimed in claim 2, characterized in that: The method also includes: According to the difference between the secondary load of the secondary circuit of the tested vehicle current load box and the external circuit and the range specified in the regulations, a secondary circuit modification suggestion is provided to the user.

4. The method for automatically calibrating the on-board current load box of a metrological test vehicle according to claim 1, characterized in that: The verification includes: The resistance, inductance and power data of the tested on-board current load box are calculated according to the main load of the tested on-board current load box, and the resistance, inductance and power data are checked to see whether they meet the preset requirements.

5. The method for automatically calibrating the on-board current load box of a metrological test vehicle as claimed in claim 4, characterized in that: The method also includes: judging whether the resistance and inductance of the tested vehicle-mounted current load box need to be corrected according to the resistance, inductance and power data, and, when the resistance and inductance of the tested vehicle-mounted current load box need to be corrected, calculating the required correction values ​​of the resistance and inductance.

6. An automatic calibration system for an on-board current load box of a metrological test vehicle, using the automatic calibration method for an on-board current load box of a metrological test vehicle as described in any one of claims 1 to 5, for calibrating the on-board current load box under test, characterized in that: Including current output port, current source, voltage measurement port, and control terminal; The current source is electrically connected to the current output port, and the control end is electrically connected to the voltage measurement port and the current source; the control end is used to control the current source to output a specified current to the current output port, so as to apply a test signal to the tested vehicle-mounted current load box, measure the secondary circuit of the tested vehicle-mounted current load box and the secondary load of the vehicle-mounted circuit, and measure the overall load of the main body, secondary circuit and vehicle-mounted circuit of the tested vehicle-mounted current load box; and calculate the main body load of the tested vehicle-mounted current load box based on the overall load and the secondary load, and verify the main body load of the tested vehicle-mounted current load box.

7. The automatic calibration system for the on-board current load box of a metrological test vehicle as claimed in claim 6, characterized in that: The control end is also used to determine whether the secondary load of the secondary circuit of the tested vehicle current load box and the external circuit meets the specified range of the regulations. When it does not meet the specified range of the regulations, the user is reminded to correct the load of the secondary circuit of the tested vehicle current load box.

8. The automatic calibration system for the on-board current load box of a metrological test vehicle as claimed in claim 7, characterized in that: The control end is also used to provide secondary circuit modification suggestions to the user based on the difference between the secondary load of the secondary circuit of the tested vehicle-mounted current load box and the external circuit and the range specified in the regulations.

9. The automatic calibration system for the on-board current load box of a metrological test vehicle as claimed in claim 6, characterized in that: The verification includes: The resistance, inductance and power data of the tested on-board current load box are calculated according to the main load of the tested on-board current load box, and the resistance, inductance and power data are checked to see whether they meet the preset requirements.

10. The automatic calibration system for the on-board current load box of a metrological test vehicle as claimed in claim 9, characterized in that: The control end is also used to determine whether the resistance and inductance of the tested vehicle-mounted current load box need to be corrected based on the resistance, inductance and power data, and, when the resistance and inductance of the tested vehicle-mounted current load box need to be corrected, calculate the required correction values ​​of the resistance and inductance.

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