Broadband error checking system for power voltage transformer

Abstract

The invention relates to the technical field of harmonic transformer metering, in particular to a broadband error checking system for a power voltage transformer, which comprises an electromagnetic power frequency standard voltage transformer, a harmonic standard voltage transformer, a broadband voltage regulating source, a broadband boosting power supply, a voltage transformer load box, a broadband transformer calibrator and a program control switching device, wherein the broadband voltage regulating source is connected with the broadband boost power supply, and the broadband boost power supply is connected with the electromagnetic power frequency standard voltage transformer and the harmonic standard voltage transformer. The problems that the broadband range precision of a conventional electromagnetic voltage transformer is not high, and the power frequency error of a harmonic standard voltage transformer based on the capacitive voltage divider principle cannot be increased are solved. By means of full-automatic program control switching in a double-standard-device mode, automatic verification of errors under the power frequency of 50 Hz and 2-50 harmonic waves is achieved, the test efficiency is improved, and the labor intensity is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of harmonic transformer measurement, in particular to a broadband error calibration system for power voltage transformers. Background Art

[0002] The power voltage transformer is a key component of the power system. It is a special transformer that converts high voltage signals into small voltages in proportion and transmits them to the secondary side power metering devices, measuring instruments, relay protection, and automatic devices. It is a contact element between the primary and secondary systems of the power grid. In the prior art, the voltage transformer works in an AC 50Hz or DC environment. However, with the rapid development of the power industry, the continuous access of nonlinear loads such as arc metallurgy, distributed power sources such as wind power and photovoltaic power, and fast-changing loads such as high-speed rail, and the access of a large number of rectifier equipment to the power grid have greatly increased the harmonic and interharmonic content of the power system. The voltage transformer operates in an environment containing harmonics, and frequency is a key factor affecting the error. Therefore, the measurement accuracy and operational safety and stability of the transformer in the AC power supply scenario containing harmonic components are very important. However, the common voltage transformer calibration system is an electromagnetic voltage transformer calibration system under power frequency or a capacitive voltage divider harmonic voltage transformer calibration system measured under multiple harmonics, and there is no system that can be applied to both power frequency and high-order harmonic voltage transformer calibration, and it is impossible to accurately measure the power voltage transformer to be tested. Summary of the invention

[0003] In view of the problems existing in the prior art, the present invention is proposed.

[0004] In order to solve the above technical problems, the present invention provides the following technical solutions: a broadband error calibration system for power voltage transformers, comprising an electromagnetic power frequency standard voltage transformer, a harmonic standard voltage transformer, a broadband voltage regulating source, a broadband boost power supply, a voltage transformer load box, a broadband transformer calibrator and a program-controlled switching device; wherein the broadband voltage regulating source is connected to the broadband boost power supply, the broadband boost power supply is connected to the electromagnetic power frequency standard voltage transformer and the harmonic standard voltage transformer, the voltage transformer load box is connected to the transformer to be tested, and the output signals of the electromagnetic power frequency standard voltage transformer, the harmonic standard voltage transformer and the transformer to be tested are connected to the broadband transformer calibrator to realize error measurement of the transformer to be tested.

[0005] As a preferred solution of the broadband error calibration system for power voltage transformer described in the present invention, wherein: the electromagnetic industrial frequency standard voltage transformer includes a high-voltage winding A1-X1 and a low-voltage winding 1a-2a-0, the harmonic standard voltage transformer includes a high-voltage input terminal A2-X2 and a low-voltage output terminal 3a-4a; the broadband boost power supply includes a low-voltage winding S1-S2 and a high-voltage winding S3-S4, and the low-voltage winding S1-S2 is connected to a broadband voltage regulating source.

[0006] As a preferred solution of the broadband error calibration system for power voltage transformer described in the present invention, the broadband voltage regulating source and the broadband boost power supply jointly realize the power frequency and 2 to 50 harmonic high voltage output, the output frequency is 50 to 2500Hz, and the frequency adjustment fineness is 0.1Hz; the high voltage winding S3-S4 described in the broadband boost power supply is connected in parallel with the electromagnetic power frequency standard voltage transformer A1-X1 and the harmonic standard voltage transformer A2-X2 high voltage windings, and the power frequency and 2 to 50 harmonic high voltage signals are applied to the electromagnetic power frequency standard voltage transformer and the harmonic standard voltage transformer.

[0007] As a preferred solution of the broadband error calibration system for power voltage transformer described in the present invention, wherein: the program-controlled switching device includes a standard secondary switching device and an automatic switching device; the standard secondary switching device is respectively connected to the secondary winding of the electromagnetic power frequency standard voltage transformer and the secondary winding of the harmonic standard voltage transformer, and is used for signal switching of the power frequency standard and the harmonic standard, to realize the selection of standard signals at different frequencies and meet the accuracy requirements of the standard at different frequencies; the automatic switching device is used for switching the voltage transformer load box; the program-controlled switching device is used for voltage regulation and frequency regulation of the harmonic power supply.

[0008] As a preferred solution for the wide-band error calibration system for power voltage transformers described in the present invention, the electromagnetic industrial frequency standard voltage transformer is used for error calibration and comparison at an industrial frequency of 50 Hz, is designed based on the principle of electromagnetic induction, and consists of a high-voltage winding A1-X1, a low-voltage winding 1a-2a-0, an iron core, SF6, and an air-filled insulation structure; the low-voltage winding 1a-2a-0 outputs an industrial frequency standard signal.

[0009] As a preferred solution for the broadband error calibration system for power voltage transformer described in the present invention, the harmonic standard voltage transformer is used for error measurement and comparison under 2nd to 50th harmonics, and is designed based on the principle of capacitor voltage divider. It consists of high-voltage arm capacitor, low-voltage arm capacitor, high-voltage input terminal A2-X2, and low-voltage output terminal 3a-4a. The low-voltage output terminal 3a-4a outputs a harmonic standard signal.

[0010] As a preferred solution of the broadband error calibration system for power voltage transformer described in the present invention, the low-voltage output terminals 3a-4a of the harmonic standard voltage transformer and the low-voltage windings 1a-2a-0 of the electromagnetic power frequency standard voltage transformer are connected to the standard switching device and then connected to the broadband calibrator.

[0011] As a preferred solution of the broadband error calibration system for power voltage transformers described in the present invention, the broadband calibrator is designed based on the principle of direct comparison method, and the switching of the broadband error calibration standard is realized through the program control device. Under the industrial frequency, the output signal of the electromagnetic industrial frequency standard voltage transformer is compared with the output signal of the transformer under test to realize error measurement; under high harmonics, the output signal of the harmonic standard voltage transformer is compared with the output signal of the transformer under test to realize error measurement.

[0012] As a preferred solution for the wide-band error calibration system for power voltage transformers described in the present invention, the electromagnetic standard voltage transformer is only suitable for industrial frequency measurement, and its industrial frequency accuracy is relatively high, up to 0.01 level. However, the error changes sharply under high-order harmonics, and it cannot be used as a standard under high-order harmonics. The harmonic standard voltage transformer based on the capacitor voltage division principle has good linearity under high-order harmonics after compensation, and its accuracy is relatively high, up to 0.2 level. However, it is difficult to achieve an industrial frequency of more than 0.02 level and has poor stability, and cannot be used as an error standard under industrial frequency.

[0013] As a preferred solution of the broadband error calibration system for power voltage transformers described in the present invention, the broadband voltage regulating source includes a power module and an MCU, which can automatically perform program-controlled voltage boost calibration to meet the error calibration of the power frequency error and 2 to 50 harmonic conditions of the harmonic voltage transformer; and automatically calibrate and output a test report after one-time wiring.

[0014] Beneficial effects of the present invention: The present invention connects the electromagnetic standard voltage transformer and the harmonic standard voltage transformer in parallel in the system, and uses a program-controlled switching device to automatically select the standard secondary signal under the power frequency and 2-50 harmonics for comparison with the secondary signal of the voltage transformer under test, thereby obtaining the error of the voltage transformer under the power frequency and 2-50 harmonics. The error checking principle of the present invention adopts a digital direct comparison method, by simultaneously applying the same frequency and the same magnitude of voltage to the standard voltage transformer and the voltage transformer under test, and comparing the secondary signal of the standard voltage transformer with the secondary signal of the voltage transformer under test, thereby obtaining the error of the voltage transformer under test. The present invention realizes error verification at 50-2500Hz by connecting the power frequency standard voltage transformer and the harmonic standard voltage transformer to the system at the same time and automatically switching them, thereby solving the problem that the accuracy of the electromagnetic standard voltage transformer cannot meet the verification requirement at non-power frequency and the wide-band capacitor voltage divider based on the capacitor voltage division principle is difficult to reach the 0.02 level at power frequency. The error verification requirement at power frequency and 2-50th harmonics is met by mixing the two principle standard devices. The whole process is automatically program-controlled without changing the wiring, and the efficiency is high, the error rate is low, and the safety is high.

[0015] The present invention solves the problem that the conventional electromagnetic voltage transformer has low accuracy in wide frequency range and the power frequency error of the harmonic standard voltage transformer based on the capacitor voltage divider principle cannot be increased. Through the fully automatic program-controlled switching of the dual standard device, the error automatic calibration under the power frequency of 50Hz and 2-50 harmonics is realized, the test efficiency is improved and the labor intensity is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. 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 creative work. Among them:

[0017] Figure 1 A working principle diagram of a method for wide-band error calibration of a power voltage transformer provided in an embodiment of the present invention.

[0018] Figure 2 A principle block diagram of a wide-band boost power supply for a method for wide-band error calibration of a power voltage transformer provided in an embodiment of the present invention.

[0019] Figure 3 A principle block diagram of a wide-frequency voltage regulating power supply for a method for wide-frequency error calibration of a power voltage transformer provided in an embodiment of the present invention.

[0020] Figure 4 A schematic diagram of the principle of a program-controlled device for a method of wide-band error calibration of a power voltage transformer provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0021] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the accompanying drawings.

[0022] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0023] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0024] The embodiment of the present invention provides a wide-band error calibration system for a power voltage transformer, which can solve the problem that the accuracy of the existing electromagnetic standard voltage transformer cannot meet the calibration requirements at non-industrial frequencies, and that the wide-band capacitor voltage divider based on the capacitor voltage divider principle is difficult to reach level 0.02 at industrial frequencies. The error calibration requirements at industrial frequencies and 2-50 harmonics are met by mixing the two principle standards. The entire process is automatically programmed and does not require wiring changes, with high efficiency, low error rate, and high safety.

[0025] The embodiment of the present invention provides a method for checking the broadband error of a power voltage transformer, which is used for checking the broadband error of a power voltage transformer. The method relates to the technical field of broadband error checking of power voltage transformers, including: an electromagnetic power frequency standard voltage transformer, a harmonic standard voltage transformer, a broadband voltage regulating source, a broadband boost power source, a voltage transformer load box, a broadband transformer calibrator, and a program-controlled switching device.

[0026] When conducting a wide-band error check of a power voltage transformer, the test system includes a wide-band error check system for a power voltage transformer and a transformer to be tested, and the connection method is as follows:

[0027] The broadband voltage regulation originates from the broadband boost power supply connection, the broadband boost power supply is connected to the electromagnetic power frequency standard voltage transformer and the harmonic standard voltage transformer, the voltage transformer load box is connected to the transformer under test, the output signals of the electromagnetic power frequency standard voltage transformer, the harmonic standard voltage transformer and the transformer under test are connected to the broadband transformer calibrator to realize the error measurement of the transformer under test.

[0028] Furthermore, the electromagnetic power frequency standard voltage transformer includes a high-voltage winding A1-X1, a low-voltage winding 1a-2a-0, and the harmonic standard voltage transformer includes a high-voltage input terminal A2-X2 and a low-voltage output terminal 3a-4a; the broadband boost power supply includes a low-voltage winding S1-S2 and a high-voltage winding S3-S4, and the low-voltage winding S1-S2 is connected to a broadband voltage regulating source, and the broadband voltage regulating source and the broadband boost power supply jointly realize the power frequency and 2-50 harmonic high-voltage output, the output frequency is 50-2500Hz, and the frequency adjustment fineness is 0.1Hz; the high-voltage winding S3-S4 described in the broadband boost power supply is connected in parallel with the electromagnetic power frequency standard voltage transformer A1-X1 and the harmonic standard voltage transformer A2-X2 high-voltage windings, and the power frequency and 2-50 harmonic high-voltage signals are applied to the electromagnetic power frequency standard voltage transformer and the harmonic standard voltage transformer.

[0029] Furthermore, the program-controlled switching device includes a standard secondary switching device and an automatic switching device.

[0030] The standard secondary switching device is respectively connected to the secondary winding of the electromagnetic power frequency standard voltage transformer and the secondary winding of the harmonic standard voltage transformer, and is used for signal switching of the power frequency standard and the harmonic standard, realizing the selection of standard signals at different frequencies and meeting the accuracy requirements of the standard devices at different frequencies; the automatic switching device is used for switching the voltage transformer load box; the program-controlled switching device is used for voltage regulation and frequency regulation of the harmonic power supply.

[0031] Furthermore, the electromagnetic power frequency standard voltage transformer is used for error verification and comparison at a power frequency of 50 Hz, is designed based on the electromagnetic induction principle, and is composed of a high-voltage winding A1-X1, a low-voltage winding 1a-2a-0, an iron core, SF6, and a gas-filled insulation structure; the low-voltage winding 1a-2a-0 outputs a power frequency standard signal;

[0032] Furthermore, the harmonic standard voltage transformer is used for error measurement and comparison under 2-50 harmonics, is designed based on the capacitor voltage divider principle, and consists of a high-voltage arm capacitor, a low-voltage arm capacitor, a high-voltage input terminal A2-X2, and a low-voltage output terminal 3a-4a. The low-voltage output terminal 3a-4a outputs a harmonic standard signal.

[0033] Furthermore, the low voltage output terminals 3a-4a of the harmonic standard voltage transformer and the low voltage windings 1a-2a-0 of the electromagnetic power frequency standard voltage transformer are connected to the standard switching device and then connected to the broadband calibration instrument;

[0034] Furthermore, the broadband calibrator is designed based on the principle of direct comparison method, and the switching of the standard device for broadband error calibration is realized through the program control device. Under the industrial frequency, the output signal of the electromagnetic industrial frequency standard voltage transformer is compared with the output signal of the transformer under test to realize error measurement; under high harmonics, the output signal of the harmonic standard voltage transformer is compared with the output signal of the transformer under test to realize error measurement.

[0035] Furthermore, the broadband voltage regulating source includes a power module and an MCU, which can automatically perform program-controlled voltage boost verification to meet the power frequency error of the harmonic voltage transformer and the error verification under 2-50 harmonic conditions; and automatically verify and output a test report after one-time wiring.

[0036] The electromagnetic standard voltage transformer is only suitable for industrial frequency measurement, and its industrial frequency accuracy can reach 0.01 level. However, the error changes sharply under high-order harmonics, and it cannot be used as a standard under high-order harmonics. The harmonic standard voltage transformer based on the capacitor voltage division principle has good linearity under high-order harmonics after compensation, and its accuracy can reach 0.2 level. However, it is difficult to achieve an industrial frequency of more than 0.02 level and the stability is poor, so it cannot be used as an error standard under industrial frequency.

[0037] See also Figure 1As shown, a method for wide-band error calibration of power voltage transformer includes: an electromagnetic power frequency standard voltage transformer, a harmonic standard voltage transformer, a wide-band voltage regulating source, a wide-band boost power supply, a voltage transformer load box, a wide-band transformer calibrator and a program-controlled switching device.

[0038] See also Figure 2 As shown, a method for wide-band error calibration of a power voltage transformer uses a wide-band boost power supply, which includes a wide-band voltage regulating power supply and a wide-band boost power supply.

[0039] See also Figure 3 As shown, a method for wide-band error calibration of power voltage transformer uses a cross-screen voltage-regulating power supply, adopts rectification, inversion and waveform synthesis technology, outputs a wide-band voltage-regulating power supply with independent VF regulation, an output frequency of 50-2500Hz, and an adjustment fineness of 0.1Hz.

[0040] See also Figure 4 As shown, a method for wide-band error calibration of power voltage transformer uses a program-controlled device for switching secondary signals of a standard device, for adjusting a program-controlled wide-band voltage-regulating power supply, and for switching loads of a program-controlled voltage transformer load box.

[0041] Importantly, it should be noted that the construction and arrangement of the present application shown in a plurality of different exemplary embodiments are only exemplary. Although only a few embodiments are described in detail in this disclosure, it should be readily understood by those who refer to this disclosure that many modifications are possible (e.g., the size, scale, structure, shape and proportion of various elements, and parameter values ​​(e.g., temperature, pressure, etc.), installation arrangement, use of materials, color, directional changes, etc.) without substantially departing from the novel teachings and advantages of the subject matter described in the application. For example, the element shown as integrally formed can be composed of multiple parts or elements, the position of the element can be inverted or otherwise changed, and the nature or number or position of the discrete element can be changed or changed. Therefore, all such modifications are intended to be included in the scope of the present invention. The order or sequence of any process or method steps can be changed or reordered according to alternative embodiments. In the claims, any "device plus function" clause is intended to cover the structure of performing the function described herein, and is not only structurally equivalent but also equivalent structure. Without departing from the scope of the present invention, other replacements, modifications, changes and omissions can be made in the design, operating conditions and arrangement of the exemplary embodiments. Therefore, the invention is not limited to a specific embodiment, but extends to numerous modifications still falling within the scope of the appended claims.

[0042] Additionally, in order to provide a concise description of exemplary embodiments, all features of an actual embodiment (ie, those features that are not relevant to the best mode presently contemplated for carrying out the invention or those that are not relevant to implementing the invention) may not be described.

[0043] It will be appreciated that in the development of any actual implementation, as in any engineering or design project, numerous implementation-specific decisions may be made. Such a development effort may be complex and time-consuming, but will be a routine task of design, fabrication, and production for those of ordinary skill having the benefit of this disclosure without undue experimentation.

[0044] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A broadband error calibration system for power voltage transformer, characterized in that: include, Electromagnetic power frequency standard voltage transformer, harmonic standard voltage transformer, wide-band voltage regulating source, wide-band boost power supply, voltage transformer load box, wide-band transformer tester and program-controlled switching device; among them, The broadband voltage regulating source is connected to the broadband boost power supply, the broadband boost power supply is connected to the electromagnetic power frequency standard voltage transformer and the harmonic standard voltage transformer, the voltage transformer load box is connected to the transformer under test, and the output signals of the electromagnetic power frequency standard voltage transformer, the harmonic standard voltage transformer and the transformer under test are connected to the broadband transformer calibrator to realize the error measurement of the transformer under test.

2. The broadband error calibration system for power voltage transformer according to claim 1, characterized in that: The electromagnetic industrial frequency standard voltage transformer includes a high voltage winding and a low voltage winding, and the harmonic standard voltage transformer includes a high voltage input terminal and a low voltage output terminal; the broadband boost power supply includes a low voltage winding and a high voltage winding, and the low voltage winding is connected to a broadband voltage regulating source.

3. The broadband error calibration system for power voltage transformer according to claim 2, characterized in that: The wide-band voltage regulating source and the wide-band boost power supply jointly realize the industrial frequency and 2-50th harmonic high-voltage output, the output frequency is 50-2500Hz, and the frequency adjustment fineness is 0.1Hz; the high-voltage winding of the wide-band boost power supply is connected in parallel with the high-voltage winding of the electromagnetic industrial frequency standard voltage transformer and the harmonic standard voltage transformer, and the industrial frequency and 2-50th harmonic high-voltage signals are applied to the electromagnetic industrial frequency standard voltage transformer and the harmonic standard voltage transformer.

4. The broadband error calibration system for power voltage transformer according to claim 2, characterized in that: The program-controlled switching device includes a standard secondary switching device and an automatic switching device; The standard secondary switching device is respectively connected to the secondary winding of the electromagnetic power frequency standard voltage transformer and the secondary winding of the harmonic standard voltage transformer, and is used for signal switching of the power frequency standard and the harmonic standard, realizing the selection of standard signals at different frequencies and meeting the accuracy requirements of the standard devices at different frequencies; the automatic switching device is used for switching the voltage transformer load box; the program-controlled switching device is used for voltage regulation and frequency regulation of the harmonic power supply.

5. The broadband error calibration system for power voltage transformer according to claim 3, characterized in that: Electromagnetic power frequency standard voltage transformer, used for error verification and comparison at power frequency of 50Hz, is designed based on the principle of electromagnetic induction and consists of high-voltage winding, low-voltage winding, iron core, SF6, and gas-filled insulation structure; the low-voltage winding outputs the power frequency standard signal.

6. The broadband error calibration system for power voltage transformer according to claim 4, characterized in that: Harmonic standard voltage transformer, used for error measurement and comparison under 2nd to 50th harmonics, is designed based on the principle of capacitor voltage divider and consists of high-voltage arm capacitor, low-voltage arm capacitor, high-voltage input terminal and low-voltage output terminal. The low-voltage output terminal outputs harmonic standard signal.

7. The broadband error calibration system for power voltage transformer according to claim 6, characterized in that: After the low-voltage output terminal of the harmonic standard voltage transformer and the low-voltage winding of the electromagnetic power frequency standard voltage transformer are connected to the standard switching device, they are connected to the broadband calibrator.

8. The broadband error calibration system for power voltage transformer according to claim 7, characterized in that: The broadband calibrator is designed based on the principle of direct comparison method. The switching of the broadband error calibration standard is realized through the program control device. Under the industrial frequency, the output signal of the electromagnetic industrial frequency standard voltage transformer is compared with the output signal of the transformer under test to realize error measurement. Under high harmonics, the output signal of the harmonic standard voltage transformer is compared with the output signal of the transformer under test to realize error measurement.

9. The broadband error calibration system for power voltage transformer according to claim 8, characterized in that: The electromagnetic standard voltage transformer is only suitable for industrial frequency measurement, and its industrial frequency accuracy can reach 0.01 level. However, the error changes sharply under high-order harmonics, and it cannot be used as a standard under high-order harmonics. The harmonic standard voltage transformer based on the capacitor voltage division principle has good linearity under high-order harmonics after compensation, and its accuracy can reach 0.2 level. However, it is difficult to achieve an industrial frequency of more than 0.02 level and the stability is poor, so it cannot be used as an error standard under industrial frequency.

10. The broadband error calibration system for power voltage transformer according to claim 9, characterized in that: The broadband voltage regulating source includes a power module and an MCU, and can automatically perform program-controlled voltage boost verification to meet the power frequency error of the harmonic voltage transformer and the error verification under the conditions of 2 to 50 harmonics; and can automatically perform verification after one-time wiring and automatically output a test report.

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