A method and device for compensating for errors in the calibration of a DC high voltage divider

Abstract

The application discloses a method and device for compensating for DC high-voltage divider verification and calibration errors, comprising: connecting a high-stability DC high-voltage source to a standard DC high-voltage divider and a detected DC high-voltage divider; synchronously collecting low-voltage arm voltages of the standard DC high-voltage divider and the detected DC high-voltage divider; substituting the low-voltage arm voltages into a previously constructed mathematical model of the DC high-voltage divider to obtain the division ratios of the standard DC high-voltage divider and the detected DC high-voltage divider; determining an influence factor of the DC high-voltage divider according to the division ratios of the standard DC high-voltage divider and the detected DC high-voltage divider; and compensating for calibration errors of the detected DC high-voltage divider according to the influence factor. The application solves the problem of inaccurate measurement of the input impedance of a meter.

Description

Technical Field

[0001] The present application relates to the technical field of high voltage and high current testing, and in particular to a method and device for compensating for calibration errors of a DC high voltage voltage divider. Background Art

[0002] Since the 1970s, foreign countries have successively established DC high-voltage standards for voltage levels of 100kV or higher. The measurement capabilities and levels of various high-voltage DC high-voltage dividers have gradually improved. Domestically, two calibration methods for DC high-voltage dividers have been proposed, and comparative verification experiments have been conducted. With the improvement of measurement capabilities, the accuracy requirements for DC high-voltage dividers have also increased. Research based on the characteristics of the divider's own resistor components and leakage current under high voltage has gradually been carried out. A method for measuring the temperature coefficient and voltage coefficient of precision resistors under high voltage has been proposed, providing a reference for selecting DC high-voltage divider resistor materials and improving the measurement uncertainty level of the divider at the component level. A leakage current measurement device for DC high-voltage resistor dividers has been proposed, which can effectively overcome the effects of power supply ripple and drift on measurement accuracy. The leakage current measurement optimizes the divider design and further improves the measurement accuracy of the divider under high voltage. Methods for improving the measurement level of the divider have been proposed from the design aspects of heat dissipation and radial discharge theory.

[0003] Currently, the influence of measurement system deviations is theoretically limited. A brief discussion of the precise measurement of the voltage divider ratio using dual digital voltmeters focuses on synchronizing the data acquisition between the two meters to minimize the effects of power supply ripple. In reality, most measuring instruments introduce input impedance, which can directly affect the measurement results, particularly when measuring DC voltages exceeding 10V. By conducting a test to verify the effect of meter input impedance on voltage divider ratio measurements, we determine the component of the meter input impedance's influence on the measurement results and propose a method for correcting the measurement results. By correcting the measurement results after the input impedance is introduced, the measurement level is more closely aligned with the actual measurement result.

[0004] The calibration of DC high-voltage dividers is based on the National Metrology Verification Regulation JJG 1007-2005, "DC High-Voltage Dividers." This regulation provides three verification methods for DC high-voltage dividers, primarily employing the difference method and the voltage ratio method in both laboratory and field environments. It's generally believed that the input impedance of the low-voltage arm meter significantly affects the measurement of the DC high-voltage divider ratio, but the precise impact of input impedance on these two measurement methods and the magnitude of this influence are lacking. Summary of the Invention

[0005] To solve the above problem, the present application provides a method for compensating for calibration errors of a DC high-voltage voltage divider, comprising:

[0006] Pass the high-stable DC high-voltage source through the standard DC high-voltage divider and the DC high-voltage divider to be tested respectively;

[0007] Synchronously collect the voltage of the low-voltage arms of the standard DC high-voltage divider and the DC high-voltage divider under test;

[0008] Substituting the low-voltage arm voltage into a pre-built mathematical model of a DC high-voltage voltage divider to obtain voltage division ratios of a standard DC high-voltage voltage divider and a DC high-voltage voltage divider under test;

[0009] determining an influence factor of the DC high-voltage divider according to a voltage divider ratio between the standard DC high-voltage divider and the DC high-voltage divider under test;

[0010] The calibration error of the tested DC high-voltage voltage divider is compensated according to the influencing factor.

[0011] Furthermore, synchronously collecting the low-voltage arm voltages of the standard DC high-voltage divider and the DC high-voltage divider under test includes: triggering a DC digital voltmeter through a synchronous trigger module, and having the DC digital voltmeter synchronously collect the low-voltage arm voltages of the standard DC high-voltage divider and the DC high-voltage divider under test.

[0012] Furthermore, the mathematical model of the DC high-voltage divider is obtained by introducing the meter input impedance to obtain the voltage division ratio of the DC high-voltage divider under test, specifically:

[0013]

[0014] Among them, K x ′ is the voltage divider ratio of the DC high voltage divider under test after the meter input impedance is introduced, K0 is the standard voltage divider ratio of the standard DC high voltage divider, U0′ is the output voltage of the standard DC high voltage divider after the meter input impedance is introduced, U x ′ is the output voltage of the DC high voltage divider under test with the meter input impedance introduced, K x is the voltage divider ratio of the DC high voltage divider under test, R Lx R is the resistance of the low-voltage arm of the DC high-voltage divider under test, M is the meter input impedance, R L It is the low voltage arm resistance of the standard DC high voltage divider.

[0015] Furthermore, determining the influence factor of the DC high voltage divider according to the voltage divider ratio of the standard DC high voltage divider and the DC high voltage divider under test includes:

[0016] According to the mathematical model of the DC high voltage divider, we can get

[0017]

[0018] The impedance of the meter introduced for DC measurement is in the MΩ level, and the low-voltage arm of the voltage divider is in the kΩ level. The mathematical model of the DC high-voltage divider can be simplified as follows:

[0019]

[0020] Among them, ΔR is the difference between the resistance of the low-voltage arm of the standard DC high-voltage divider and the DC high-voltage divider under test, In order to introduce the deviation of the voltage divider ratio measurement after the meter input impedance is introduced, the deviation is used as an influencing factor.

[0021] Furthermore, compensating for a calibration error of the tested DC high-voltage divider according to the influencing factor includes:

[0022] According to the fact that the influence factor is positively correlated with the resistance difference between the low-voltage arms of the standard DC high-voltage divider and the DC high-voltage divider under test, and negatively correlated with the meter input impedance, compensation is performed by correcting the influence factor on the measurement result.

[0023] The present application also provides a device for compensating for calibration errors of a DC high-voltage voltage divider, comprising:

[0024] The high-voltage source access unit is used to connect the high-stable DC high-voltage source through the standard DC high-voltage divider and the DC high-voltage divider to be tested;

[0025] A synchronous acquisition unit, used for synchronously acquiring the voltages of the low-voltage arms of the standard DC high-voltage divider and the DC high-voltage divider under test;

[0026] a voltage division ratio obtaining unit, configured to substitute the low-voltage arm voltage into a pre-built mathematical model of a DC high-voltage voltage divider, and obtain voltage division ratios of a standard DC high-voltage voltage divider and a DC high-voltage voltage divider under test;

[0027] The influence factor determination unit is used to determine the influence factor of the DC high voltage divider according to the standard DC high voltage divider and the DC high voltage divider to be tested.

[0028] The voltage divider ratio of the device is used to determine the influencing factor of the DC high voltage divider;

[0029] A compensation unit is used to compensate for the calibration error of the tested DC high-voltage divider according to the influencing factor.

[0030] The present application provides a method and device for compensating for calibration errors in a DC high-voltage voltage divider. After compensating for the calibration errors in a DC high-voltage voltage divider based on a voltage ratio method, the deviation between the measurement result and the actual measurement result does not exceed 0.01%. The voltage divider ratio design for each voltage level is no longer limited to secondary voltages below 10V. This method can still be used for voltage dividers with poor field environments, high voltage levels, and secondary voltages exceeding 10V, while ensuring its measurement accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 1 is a flow chart of a method for compensating for calibration errors of a DC high-voltage voltage divider provided in an embodiment of the present application;

[0032] Figure 2 The invention relates to a voltage comparison method verification / calibration mathematical model involving the input impedance of a meter according to an embodiment of the present application;

[0033] Figure 3 This is a voltage ratio verification / calibration model involving input impedance according to an embodiment of the present application;

[0034] Figure 4 These are the test data under different partial pressure ratios involved in the embodiments of this application;

[0035] Figure 5 Schematic diagram of a device for compensating for calibration errors of a DC high-voltage voltage divider provided in an embodiment of the present application. DETAILED DESCRIPTION

[0036] The following description sets forth many specific details to facilitate a thorough understanding of the present application. However, the present application can be implemented in many other ways than those described herein, and those skilled in the art can make similar generalizations without violating the scope of the present application. Therefore, the present application is not limited to the specific implementations disclosed below.

[0037] Figure 1 This is a flow chart of a method for compensating for calibration errors of a DC high voltage voltage divider provided in an embodiment of the present application. Figure 1 The method provided in the embodiments of the present application is described in detail.

[0038] Step S101, passing a high-stable DC high-voltage source through a standard DC high-voltage voltage divider and a DC high-voltage voltage divider to be tested respectively;

[0039] The voltage ratio method verification / calibration model involving the introduction of input impedance involved in the present invention is as follows: Figure 3 As shown, after the high-stable DC high-voltage source passes through the standard DC high-voltage divider and the DC high-voltage divider to be tested, the low-voltage arm voltage is collected by a DC digital voltmeter.

[0040] Step S102 : synchronously collecting the voltages of the low-voltage arms of the standard DC high-voltage divider and the DC high-voltage divider under test.

[0041] The DC digital voltmeter is triggered by the synchronous trigger module, and the DC digital voltmeter synchronously collects the low-voltage arm voltages of the standard DC high-voltage voltage divider and the DC high-voltage voltage divider to be tested.

[0042] like Figure 3As shown in the figure, the DC digital high-voltage meter is connected to the host computer through the GPIB to USB interface. The host computer program is written in LABVIEW, and the function setting and data acquisition of the DC digital voltmeter are realized through the USB-GPIB communication process, so that the host computer can realize the synchronous sampling of the DC digital high-voltage meter and perform data processing.

[0043] Step S103 , substituting the low-voltage arm voltage into a pre-built mathematical model of a DC high-voltage voltage divider to obtain voltage division ratios of a standard DC high-voltage voltage divider and a tested DC high-voltage voltage divider.

[0044] Figure 2 The calculation formula of the voltage ratio of the DC high voltage divider using the medium voltage ratio method is:

[0045]

[0046] in therefore

[0047]

[0048] Similarly:

[0049]

[0050] The mathematical model for voltage comparison verification / calibration with input impedance of meter is as follows: Figure 2 As shown:

[0051] After the input impedance is introduced, the actual low-voltage arm resistance is R L The internal resistance R M Parallel connection, low voltage arm resistance:

[0052]

[0053] Likewise, there are:

[0054]

[0055] Substituting into (2) and (3) respectively, we get:

[0056]

[0057] Substituting (6) and (7) into (1), we can obtain the voltage divider ratio of the DC high voltage divider under test, as follows:

[0058]

[0059] Among them, K x′ is the voltage divider ratio of the DC high voltage divider under test after the meter input impedance is introduced, K0 is the standard voltage divider ratio of the standard DC high voltage divider, U0′ is the output voltage of the standard DC high voltage divider after the meter input impedance is introduced, U x ′ is the output voltage of the DC high voltage divider under test with the meter input impedance introduced, K x is the voltage divider ratio of the DC high voltage divider under test, R Lx R is the resistance of the low-voltage arm of the DC high-voltage divider under test, M is the meter input impedance, R L It is the low voltage arm resistance of the standard DC high voltage divider.

[0060] Step S104 : determining an influence factor of the DC high voltage divider according to a voltage divider ratio between the standard DC high voltage divider and the DC high voltage divider to be tested.

[0061] For formula (8), we also have

[0062]

[0063] The 344 series multimeter used in the present invention has an impedance of MΩ under DC measurement and a low-voltage arm of the voltage divider of kΩ. The equation (9) can be simplified to

[0064]

[0065] Among them, ΔR is the difference between the resistance of the low-voltage arm of the standard DC high-voltage divider and the DC high-voltage divider under test, In order to introduce the deviation of the voltage divider ratio measurement after the meter input impedance is introduced, the deviation is used as the influencing factor. It can be concluded from formula (10) that there is a deviation in the voltage divider ratio measurement after the meter input impedance is introduced. For the convenience of statement, the theoretical deviation value is called the influencing factor, and the magnitude of the influencing factor is (ΔR is the difference in resistance between the low-voltage arms of the standard and the test piece).

[0066] Step S105 : compensating for the calibration error of the tested DC high-voltage divider according to the influencing factor.

[0067] Because the impact factor is positively correlated with the resistance difference between the low-voltage arms of the standard DC high-voltage divider and the DC high-voltage divider under test, and negatively correlated with the meter input impedance, compensation is achieved by correcting the impact factor on the measurement results. A specific application example is as follows: A test sample with a rated voltage of 40 kV was tested using the voltage ratio method and other methods (difference method). The voltage ratio data measured at 10%, 20%, 50%, 80%, and 100% of the rated voltage are shown in Tables 1, 2, and 3.

[0068] Table 1 Test data of voltage ratio method without compensation

[0069]

[0070] Table 2 Actual voltage ratio test data

[0071]

[0072]

[0073] Table 3 Test data of difference method under normal input impedance and high impedance input

[0074]

[0075] In order to facilitate the comparison of test results, the measurement results of each voltage point are shown in Figure 4 Expressed in the form of Figure 4 It can be seen that the results without compensation method have a larger deviation from other methods (which can be approximately regarded as true results).

[0076] As a control, a verification test was conducted on the test piece at 10000:1 using a standard DC high voltage divider at 100000:1. According to formula (10), the influencing factors are:

[0077]

[0078] The voltage divider ratio test data obtained through the experiment is shown in Table 4.

[0079] Table 4 Compensated voltage divider ratio and actual voltage divider ratio

[0080]

[0081] Experimental data show that the partial pressure ratio after correction of the influencing factor is very close to the actual partial pressure ratio of the test sample.

[0082] Based on the same inventive concept, a device 500 for compensating for calibration errors of a DC high voltage divider is provided. Figure 5 As shown, including:

[0083] The high voltage source access unit 510 is used to connect the high stable DC high voltage source through the standard DC high voltage divider and the DC high voltage divider under test respectively;

[0084] Synchronous acquisition unit 520, used for synchronously acquiring the voltage of the low-voltage arms of the standard DC high-voltage divider and the DC high-voltage divider under test;

[0085] A voltage division ratio acquisition unit 530 is configured to substitute the low-voltage arm voltage into a pre-built mathematical model of a DC high-voltage voltage divider to obtain voltage division ratios of a standard DC high-voltage voltage divider and a DC high-voltage voltage divider under test, respectively;

[0086] An influence factor determination unit 540 is configured to determine an influence factor of the DC high voltage divider based on a voltage divider ratio between the standard DC high voltage divider and the DC high voltage divider under test;

[0087] The compensation unit 550 is configured to compensate for the calibration error of the tested DC high-voltage divider according to the influencing factor.

[0088] The present application provides a method and device for compensating for calibration errors in a DC high-voltage voltage divider. After compensating for the calibration errors in a DC high-voltage voltage divider based on a voltage ratio method, the deviation between the measurement result and the actual measurement result does not exceed 0.01%. The voltage divider ratio design for each voltage level is no longer limited to secondary voltages below 10V. This method can still be used for voltage dividers with poor field environments, high voltage levels, and secondary voltages exceeding 10V, while ensuring its measurement accuracy.

[0089] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be included in the scope of the claims of the present invention.

Claims

1. A method for compensating for calibration errors of a DC high voltage divider, characterized in that: include: Pass the high-stable DC high-voltage source through the standard DC high-voltage divider and the DC high-voltage divider to be tested respectively; Synchronously collect the voltage of the low-voltage arms of the standard DC high-voltage divider and the DC high-voltage divider under test; Substituting the low-voltage arm voltage into a pre-built mathematical model of a DC high-voltage voltage divider to obtain voltage division ratios of a standard DC high-voltage voltage divider and a DC high-voltage voltage divider under test; determining an influence factor of the DC high-voltage divider according to a voltage divider ratio between the standard DC high-voltage divider and the DC high-voltage divider under test; The calibration error of the tested DC high voltage divider is compensated according to the influencing factor; wherein, The mathematical model of the DC high-voltage divider is obtained by introducing the meter input impedance to obtain the voltage divider ratio of the DC high-voltage divider under test, specifically: Among them, K x ′ is the voltage divider ratio of the DC high voltage divider under test after the meter input impedance is introduced, K0 is the standard voltage divider ratio of the standard DC high voltage divider, U0′ is the output voltage of the standard DC high voltage divider after the meter input impedance is introduced, U x ′ is the output voltage of the DC high voltage divider under test with the meter input impedance introduced, K x is the voltage divider ratio of the DC high voltage divider under test, R Lx R is the resistance of the low-voltage arm of the DC high-voltage divider under test, M is the meter input impedance, R L It is the resistance of the low voltage arm of the standard DC high voltage divider; Determining an influencing factor of the DC high-voltage divider based on a voltage divider ratio between the standard DC high-voltage divider and the DC high-voltage divider under test includes: According to the mathematical model of the DC high voltage divider, we can get The impedance of the meter introduced for DC measurement is in the MΩ level, and the low-voltage arm of the voltage divider is in the kΩ level. The above formula can be simplified to: Among them, ΔR is the difference between the resistance of the low-voltage arm of the standard DC high-voltage divider and the DC high-voltage divider under test, In order to introduce the deviation of the voltage divider ratio measurement after the meter input impedance is introduced, the deviation is used as an influencing factor; Compensating for a calibration error of the tested DC high-voltage voltage divider according to the influencing factor includes: According to the fact that the influence factor is positively correlated with the resistance difference between the low-voltage arms of the standard DC high-voltage divider and the DC high-voltage divider under test, and negatively correlated with the meter input impedance, compensation is performed by correcting the influence factor on the measurement result.

2. The method according to claim 1, characterized in that Synchronously collecting the voltages of the low-voltage arms of a standard DC high-voltage divider and a DC high-voltage divider under test, comprising: triggering a DC digital voltmeter through a synchronous trigger module, and using the DC digital voltmeter to synchronously collect the voltages of the low-voltage arms of the standard DC high-voltage divider and the DC high-voltage divider under test.

3. A device for compensating for calibration errors of a DC high voltage divider, using the method according to any one of claims 1 to 2, characterized in that: include: The high-voltage source access unit is used to connect the high-stable DC high-voltage source through the standard DC high-voltage divider and the DC high-voltage divider to be tested; A synchronous acquisition unit, used for synchronously acquiring the voltages of the low-voltage arms of the standard DC high-voltage divider and the DC high-voltage divider under test; a voltage division ratio obtaining unit, configured to substitute the low-voltage arm voltage into a pre-built mathematical model of a DC high-voltage voltage divider, and obtain voltage division ratios of a standard DC high-voltage voltage divider and a DC high-voltage voltage divider under test; An influence factor determination unit, configured to determine an influence factor of the DC high-voltage divider based on a voltage divider ratio between the standard DC high-voltage divider and the DC high-voltage divider to be tested; A compensation unit is used to compensate for the calibration error of the tested DC high-voltage voltage divider according to the influencing factor.

Images