A voltage transformer environment electromagnetic field experimental device

Abstract

The application discloses a voltage transformer environmental electromagnetic field experimental device and a testing method thereof. The voltage transformer environmental electromagnetic field experimental device comprises a collecting unit, a control processing unit, a power supply unit, a standard voltage transformer, a voltage booster and a circuit switching switch. Four fixed ends in the circuit switching switch are divided into two groups and arranged on the two sides of two movable ends. The two movable ends can be connected with the fixed ends on the two sides respectively. The second end of the secondary side of the standard voltage transformer is connected with the second fixed end and the third fixed end arranged in a staggered mode through wires respectively. The first end of the secondary side of the voltage transformer to be measured is connected with the first fixed end and the fourth fixed end arranged in a staggered mode through wires respectively. The application makes the wiring of the voltage transformer environmental electromagnetic field interference experiment simple, and the wiring does not need to be adjusted in the measurement process. The signal data collection and processing of the collecting unit, the control processing unit and the man-machine interaction unit are facilitated, and the accuracy of the experiment is ensured.

Description

Technical Field

[0001] This invention relates to a voltage transformer calibration device for laboratory environmental electromagnetic fields, specifically a voltage transformer environmental electromagnetic field experimental device. Background Technology

[0002] Voltage transformers in power systems are important high-voltage transmission and transformation equipment, primarily used for voltage measurement in energy metering and signal sampling devices for relay protection. Energy trade settlements between power plants and the power grid, between the power grid and the power supply company, and between the power supply company and high-voltage users are all conducted through high-voltage energy metering devices.

[0003] According to relevant verification procedures, voltage transformers must undergo on-site weekly inspections every 4 to 10 years. When verifying voltage transformers at the plant site, there is significant electromagnetic interference in the environment. If the influence of the environmental electromagnetic field on the voltage transformer measurement results cannot be identified, it is difficult to guarantee the accuracy of the on-site verification results. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the defects of the prior art and provide a voltage transformer environmental electromagnetic field test device to effectively identify the influence of the environmental electromagnetic field on the measurement results of the voltage transformer under test and ensure the accuracy of the on-site verification results of the voltage transformer.

[0005] Therefore, the present invention adopts the following technical solution: an environmental electromagnetic field experimental device for a voltage transformer, comprising a data acquisition unit, a control and processing unit, a power supply unit, a standard voltage transformer, a step-up transformer, and a circuit switching switch, wherein the step-up transformer is connected in parallel to the primary side of the standard voltage transformer; the power supply unit is connected to the data acquisition unit and the control and processing unit respectively to provide power supply.

[0006] The acquisition unit includes a signal acquisition module, sampling resistors R1 and R2, and a current conversion transformer. The signal acquisition module contains at least three acquisition channels. The input and output terminals of the first acquisition channel are connected to both ends of the sampling resistor R1, respectively, for acquiring the signal from the standard voltage transformer. The sampling resistor R1 is connected in parallel to the secondary side of the standard voltage transformer. The input and output terminals of the second acquisition channel are connected to both ends of the sampling resistor R2, respectively, for acquiring the signal from the voltage transformer under test. The sampling resistor R2 is connected in parallel to the secondary side of the current conversion transformer. The input and output terminals of the third acquisition channel are used to acquire the electrical signals of the power supply unit.

[0007] The first terminal of the primary side of the current conversion transformer is used to connect to the second terminal of the secondary side of the standard voltage transformer, and the second terminal of the primary side of the current conversion transformer is used to connect to the first terminal of the secondary side of the voltage transformer under test.

[0008] The circuit switching switch has a first movable terminal, a second movable terminal, a first fixed terminal, a second fixed terminal, a third fixed terminal, and a fourth fixed terminal. The two movable terminals are fixedly connected to the two ends of the primary side of the current conversion transformer, respectively. The four fixed terminals are divided into two groups and arranged on both sides of the two movable terminals. The two movable terminals can be connected to the fixed terminals on both sides respectively. The second end of the secondary side of the standard voltage transformer is connected to the staggered second and third fixed terminals through wires. The first end of the secondary side of the voltage transformer under test is connected to the staggered first and fourth fixed terminals through wires.

[0009] Furthermore, the first terminal of the secondary side of the standard voltage transformer is connected to the second terminal of the secondary side of the voltage transformer under test.

[0010] Furthermore, the first terminal of the primary side of the standard voltage transformer is grounded, and the second terminal of the primary side of the standard voltage transformer is used for electrical connection with the first terminal of the primary side of the voltage transformer under test.

[0011] Furthermore, the first terminal of the primary side of the standard voltage transformer is located on the same side as the first terminal of the secondary side of the standard voltage transformer, and the second terminal of the primary side of the standard voltage transformer is located on the same side as the second terminal of the secondary side of the standard voltage transformer.

[0012] Furthermore, the second terminal of the primary side of the voltage transformer under test is grounded.

[0013] Furthermore, the second terminal of the secondary side of the voltage transformer under test is grounded.

[0014] Furthermore, the two ends of the secondary side of the voltage transformer under test are electrically connected to the load box.

[0015] Furthermore, the signal lines of a standard voltage transformer are shielded twisted-pair cables.

[0016] Furthermore, the voltage transformer environmental electromagnetic field experimental device also includes a human-machine interaction unit. The power supply unit is connected to the human-machine interaction unit to provide power. The human-machine interaction unit is connected to the control and processing unit for communication.

[0017] Furthermore, the test steps for the error interference of the laboratory environmental electromagnetic field on the experimental setup for the environmental electromagnetic field of the voltage transformer are as follows:

[0018] 1) Connect the wiring for the environmental electromagnetic field interference test in the voltage transformer calibration laboratory, and measure the ratio difference f1 and phase difference δ1 of the standard voltage transformer used for calibration of the voltage transformer environmental electromagnetic field test device at 20% of the rated primary voltage.

[0019] 2) Interchange the wiring at both ends of the primary side of the current conversion transformer through the circuit switching switch, and measure the ratio difference f2 and phase difference δ2 of the standard voltage transformer at 20% of the rated primary voltage of the environmental electromagnetic field test device for the voltage transformer at this time.

[0020] 3) The result calculated according to the following formula shall be used as the interference value of the ambient electromagnetic field on the measurement of the basic error measurement result of the voltage transformer under test by the experimental device for measuring the ambient electromagnetic field of the voltage transformer.

[0021] f x =(f1+f2) / 2, δ x = (δ1+δ2) / 2,

[0022] f x Indicates the ratio difference interference value; δ x Indicates the phase difference interference value;

[0023] When the ratio difference interference value f x and phase difference interference value δ x If none of the values ​​exceed 1 / 5 of the allowable error limit set by the voltage transformer environmental electromagnetic field test device, then the intensity of the laboratory environmental electromagnetic field interference is considered to meet the requirements.

[0024] The beneficial effects of this invention are as follows:

[0025] This invention can both perform laboratory or field error verification of voltage transformers and measure the influence of environmental electromagnetic fields on errors, ensuring the accuracy of laboratory or field verification results of voltage transformers.

[0026] This invention simplifies the wiring for experiments involving voltage transformers subjected to environmental electromagnetic interference by connecting the second end of the secondary side of a standard voltage transformer to two staggered fixed ends via wires, and connecting the first end of the secondary side of the voltage transformer under test to two other staggered fixed ends via wires. This eliminates the need to adjust the wiring during measurement, facilitates the acquisition and processing of signal data by the data acquisition unit, control processing unit, and human-machine interaction unit, and ensures the accuracy of the experiment. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a circuit diagram of the environmental electromagnetic field experimental device for the voltage transformer of the present invention;

[0029] Figure 2 This is a structural diagram of the circuit switching switch of the present invention;

[0030] In the diagram, 1-standard voltage transformer, 2-step-up transformer, 3-voltage transformer under test, 4-current conversion transformer, 5-circuit switch, 11-first terminal of the secondary side of the standard voltage transformer, 12-second terminal of the secondary side of the standard voltage transformer, 13-first terminal of the primary side of the standard voltage transformer, 14-second terminal of the primary side of the standard voltage transformer, 31-first terminal of the secondary side of the voltage transformer under test, 32-second terminal of the secondary side of the voltage transformer under test, 33-first terminal of the primary side of the voltage transformer under test, 34-second terminal of the primary side of the voltage transformer under test, 51-first movable terminal, 52-second movable terminal, 53-first fixed terminal, 54-second fixed terminal, 55-third fixed terminal, 56-fourth fixed terminal. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] like Figure 1 The experimental setup for an environmental electromagnetic field of a voltage transformer, as shown, comprises a data acquisition unit, a control and processing unit, a power supply unit, a human-machine interface unit, a standard voltage transformer 1, a step-up transformer 2, and a circuit switching switch 5. The step-up transformer 2 is connected in parallel to the primary side of the standard voltage transformer 1. The power supply unit is connected to the human-machine interface unit, the data acquisition unit, and the control and processing unit to provide power. The human-machine interface unit and the control and processing unit are interconnected for communication. The signal line of the standard voltage transformer is a shielded twisted-pair cable.

[0033] The acquisition unit includes a signal acquisition module, sampling resistors R1 and R2, and a current conversion transformer 4. The signal acquisition module contains three acquisition channels. The input and output terminals of the first acquisition channel are connected to the two ends of the sampling resistor R1, respectively, and are used to acquire the signal of the standard voltage transformer 1. The sampling resistor R1 is connected in parallel to the secondary side of the standard voltage transformer 1. The input and output terminals of the second acquisition channel are connected to the two ends of the sampling resistor R2, respectively, and are used to acquire the signal of the voltage transformer 3 under test. The sampling resistor R2 is connected in parallel to the secondary side of the current conversion transformer 4. The input and output terminals of the third acquisition channel are used to acquire the electrical signals of the power supply unit.

[0034] The first terminal of the primary side of the current conversion transformer is used to connect to the second terminal 12 of the secondary side of the standard voltage transformer, and the second terminal of the primary side of the current conversion transformer is used to connect to the first terminal 31 of the secondary side of the voltage transformer under test; the first terminal 11 of the secondary side of the standard voltage transformer is connected to the second terminal 32 of the secondary side of the voltage transformer under test.

[0035] The circuit switching switch 5 has a first movable terminal 51, a second movable terminal 52, a first fixed terminal 53, a second fixed terminal 54, a third fixed terminal 55, and a fourth fixed terminal 56. The two movable terminals are fixedly connected to the two ends of the primary side of the current conversion transformer, respectively. The four fixed terminals are divided into two groups and arranged on both sides of the two movable terminals. The two movable terminals can be connected to the fixed terminals on both sides respectively. The second end 12 of the secondary side of the standard voltage transformer is connected to the staggered second fixed terminal 54 and the third fixed terminal 55 through wires, respectively. The first end 31 of the secondary side of the voltage transformer under test is connected to the staggered first fixed terminal 53 and the fourth fixed terminal 56 through wires, respectively.

[0036] The first terminal 13 of the primary side of the standard voltage transformer is grounded, and the second terminal 14 of the primary side of the standard voltage transformer is used for electrical connection with the first terminal 33 of the primary side of the voltage transformer under test. The first terminal 13 of the primary side of the standard voltage transformer is located on the same side as the first terminal 11 of the secondary side of the standard voltage transformer, and the second terminal 14 of the primary side of the standard voltage transformer is located on the same side as the second terminal 12 of the secondary side of the standard voltage transformer.

[0037] The second terminal 34 of the primary side of the voltage transformer under test is grounded, and the second terminal 32 of the secondary side of the voltage transformer under test is grounded.

[0038] The two ends of the secondary side of the voltage transformer under test are electrically connected to the load box, and the signal line of the standard voltage transformer 1 is a shielded twisted pair cable.

[0039] The test procedure for the error interference of laboratory environmental electromagnetic fields on the experimental setup for voltage transformer environmental electromagnetic fields is as follows:

[0040] 1) Connect the wiring for the environmental electromagnetic field interference test in the voltage transformer calibration laboratory, and measure the ratio difference f1 and phase difference δ1 of the standard voltage transformer used for calibration of the voltage transformer environmental electromagnetic field test device at 20% of the rated primary voltage.

[0041] 2) Interchange the wiring at both ends of the primary side of the current conversion transformer through the circuit switching switch, and measure the ratio difference f2 and phase difference δ2 of the standard voltage transformer at 20% of the rated primary voltage of the environmental electromagnetic field test device for the voltage transformer at this time.

[0042] 3) The result calculated according to the following formula shall be used as the interference value of the ambient electromagnetic field on the measurement of the basic error measurement result of the voltage transformer under test by the experimental device for measuring the ambient electromagnetic field of the voltage transformer.

[0043] f x =(f1+f2) / 2, δ x = (δ1+δ2) / 2,

[0044] f x Indicates the ratio difference interference value; δ x Indicates the phase difference interference value;

[0045] When the ratio difference interference value f x and phase difference interference value δ x If none of the values ​​exceed 1 / 5 of the allowable error limit set by the voltage transformer environmental electromagnetic field test device, then the intensity of the laboratory environmental electromagnetic field interference is considered to meet the requirements.

[0046] The principle of error detection in this invention is as follows:

[0047] By obtaining the measured values ​​of the standard voltage transformer and the voltage transformer under test, and comparing the two, if the difference between the measured value of the voltage transformer under test and the measured value of the standard voltage transformer is within the permissible range, it means that the error of the voltage transformer under test meets the requirements. If it exceeds the permissible range, it means that the voltage transformer under test has failed and does not meet the requirements.

[0048] Meanwhile, by switching the circuit, the connection state of the circuit and the switch is changed during the calibration of the voltage transformer under test, so that the error of the voltage transformer under test can be measured at the high potential end and the low potential end respectively, and the measured values ​​are compared again to ensure the accuracy of the measurement.

[0049] In the description of this application, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0050] It should be noted that in this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes the element.

[0051] 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 them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A voltage transformer ambient electromagnetic field experiment device, characterized by, It comprises a collecting unit, a control processing unit, a power supply unit, a standard voltage transformer (1), a booster (2) and a circuit switching switch (5), the booster (2) is connected in parallel with the primary side of the standard voltage transformer (1); the power supply unit is connected with the collecting unit and the control processing unit respectively; The collecting unit comprises a signal collecting module, a sampling resistor R1, a sampling resistor R2 and a current conversion transformer (4); the signal collecting module comprises at least three collecting channels, the input and output ends of the first collecting channel are connected at the two ends of the sampling resistor R1 respectively, which is used for collecting the signal of the standard voltage transformer (1), the sampling resistor R1 is connected in parallel with the secondary side of the standard voltage transformer (1); the input and output ends of the second collecting channel are connected at the two ends of the sampling resistor R2 respectively, which is used for collecting the signal of the voltage measuring transformer (3) to be measured, the sampling resistor R2 is connected in parallel with the secondary side of the current conversion transformer (4); the input and output ends of the third collecting channel are used for collecting the power signal of the power supply unit; The first end of the primary side of the current conversion transformer is used for being connected with the second end (12) of the secondary side of the standard voltage transformer, and the second end of the primary side of the current conversion transformer is used for being connected with the first end (31) of the secondary side of the voltage measuring transformer to be measured; The circuit switching switch (5) has a first movable end (51), a second movable end (52), a first fixed end (53), a second fixed end (54), a third fixed end (55) and a fourth fixed end (56), the two movable ends are fixedly connected with the two ends of the primary side of the current conversion transformer respectively, the four fixed ends are divided into two groups and arranged on the two sides of the two movable ends respectively, the two movable ends can be connected with the fixed ends on the two sides respectively, the second end (12) of the secondary side of the standard voltage transformer is connected with the second fixed end (54) and the third fixed end (55) arranged in staggered mode through wires respectively, and the first end (31) of the secondary side of the voltage measuring transformer to be measured is connected with the first fixed end (53) and the fourth fixed end (56) arranged in staggered mode through wires respectively; The first fixed end (53) and the third fixed end (55) are arranged on the two sides of the first movable end (51) respectively, the second fixed end (54) and the fourth fixed end (56) are arranged on the two sides of the second movable end (52) respectively, and correspondingly, through the switching of the circuit switching switch, the first movable end and the second movable end are connected with the first fixed end (53) and the second fixed end (54) respectively, or the first movable end and the second movable end are connected with the third fixed end (55) and the fourth fixed end (56) respectively.

2. The voltage transformer ambient electromagnetic field test device according to claim 1, characterized in that, The first end (11) of the secondary side of the standard voltage transformer is connected with the second end (32) of the secondary side of the voltage measuring transformer to be measured.

3. The voltage transformer ambient electromagnetic field test device of claim 1, wherein, The first end (13) of the primary side of the standard voltage transformer is grounded, and the second end (14) of the primary side of the standard voltage transformer is used for being electrically connected with the first end (33) of the primary side of the voltage measuring transformer to be measured.

4. The voltage transformer ambient electromagnetic field test device of claim 3, wherein, The first end (13) of the primary side of the standard voltage transformer is located on the same side as the first end (11) of the secondary side of the standard voltage transformer, and the second end (14) of the primary side of the standard voltage transformer is located on the same side as the second end (12) of the secondary side of the standard voltage transformer.

5. The voltage transformer ambient electromagnetic field test device of claim 1, wherein, The second end (34) of the primary side of the voltage transformer to be measured is grounded.

6. The voltage transformer ambient electromagnetic field test device of claim 1, wherein, The second end (32) of the secondary side of the voltage transformer to be measured is grounded.

7. The voltage transformer ambient electromagnetic field test device of claim 1, wherein, The two ends of the secondary side of the voltage transformer to be measured are electrically connected with the load box.

8. The voltage transformer ambient electromagnetic field test device of claim 1, wherein, The signal line of the standard voltage transformer (1) is a shielded twisted pair line.

9. The voltage transformer ambient electromagnetic field test device of claim 1, wherein, Further comprising a man-machine interaction unit, the power supply unit is connected with the man-machine interaction unit, provides power supply; the man-machine interaction unit and control processing unit are connected with each other, and communication is carried out.

10. The voltage transformer ambient electromagnetic field test device according to any of claims 1 to 9, characterized in that The test steps of the error interference of the laboratory environment electromagnetic field on the environmental electromagnetic field experimental device of the voltage transformer are as follows: 1) The connection of the voltage transformer calibration laboratory electromagnetic field interference test, the measurement of the ratio of the standard voltage transformer 20% rated primary voltage under the environmental electromagnetic field test device f 1 and phase difference delta 1; 2) The connection of both ends of the primary side of the current transformer is exchanged by the circuit switching switch, and the ratio error of the standard voltage transformer 20% rated primary voltage is measured at this time f 2 and phase difference delta 2; 3) the result calculated according to the following formula is taken as the interference value of the environmental electromagnetic field on the basic error measurement result of the voltage transformer to be measured in the environmental electromagnetic field experimental device for the measurement of the voltage transformer; f x =（ f 1 +f 2） / 2， delta x =（ delta 1 + delta 2） / 2， wherein f x denotes a ratio difference interference value; delta x denotes a phase difference interference value; When the ratio difference interference value f x and the phase difference interference value delta x If the ratio difference interference value, the voltage difference interference value and the phase difference interference value are all less than 1 / 5 of the allowable error limit value set by the voltage transformer environmental electromagnetic field experimental device, it is considered that the laboratory environmental electromagnetic field interference intensity meets the requirements.

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