Whole detection system and method for current transformer live calibration device

Abstract

The invention provides a whole inspection system and method for a current transformer live calibration device, and the system comprises an interference signal generation unit which is used for generating an interference signal with configurable frequency and adjustable amplitude; the standard signal generation unit is used for generating a standard signal with adjustable frequency and amplitude; the phase shifter and the voltage divider are used for synthesizing the standard signal into a same-direction component and an orthogonal component of the error signal; the adder is used for synthesizing the interference signal, the same-direction component and the orthogonal component into an error signal mixed with the interference signal; the power amplification unit is used for carrying out V-I control and power amplification on the error signal aliasing with the interference signal and a standard signal, and outputting a differential current aliasing with the interference signal and a standard current to a live calibration device; and the main control unit is used for reading an error value measured by the live calibration device and judging whether the live calibration device is qualified or not according to the error value. The method can be used for carrying out overall verification work on the live calibration device of the current transformer based on the pilot frequency method principle.

Description

Technical Field

[0001] The invention relates to the field of verification of a live calibration device for a current transformer, and in particular to a verification system and method for a live calibration device for a current transformer. Background Art

[0002] The live calibration device for current transformers is a device that uses the frequency difference method (recommended to be 60Hz) to perform non-stop calibration on low-voltage current transformers under on-site operating conditions. The live calibration condition has 50Hz (relative to the calibrated 60Hz, the 50Hz power frequency is a strong adjacent frequency interference) and its harmonic interference. Therefore, the overall verification device for the live calibration device needs to simulate the 50Hz and its harmonics of the on-site operating conditions as interference signals while simulating the error signal, and then mix them as the test signal for the live calibration device of the current transformer. At present, there is an urgent need to set up relevant verification systems and methods for this special verification. Summary of the invention

[0003] In view of the above technical problems, the present invention provides a system for checking a current transformer live calibration device, characterized in that it comprises: an interference signal generating unit, a standard signal generating unit, a phase shifter, a voltage divider, an adder, a power amplification unit and a main control unit;

[0004] An interference signal generating unit is used to generate an interference signal composed of multiple frequency components with configurable frequency and adjustable amplitude; and transmit the interference signal to an adder;

[0005] A standard signal generating unit, used for generating a standard signal with adjustable frequency and amplitude; transmitting the standard signal to the phase shifter, the voltage divider and the power amplification unit respectively;

[0006] A phase shifter and a voltage divider, used for synthesizing the standard signal into an in-phase component and a quadrature component of an error signal; transmitting the in-phase component and the quadrature component to an adder;

[0007] An adder, used for synthesizing the interference signal, the in-phase component and the orthogonal component into an error signal aliased with the interference signal; and transmitting the error signal to a power amplification unit;

[0008] A power amplification unit, used for performing VI control and power amplification on the error signal and the standard signal mixed with the interference signal, and outputting the difference current and the standard current mixed with the interference signal to the current transformer live calibration device;

[0009] The main control unit is used to read the error value measured by the current transformer live calibration device, and judge whether the current transformer live calibration device is qualified according to the error value.

[0010] Furthermore, the interference signal generating unit is used to generate a frequency-configurable and amplitude-adjustable interference signal composed of multiple frequency components, wherein the interference signal n 1 The specific expression of (t) is:

[0011]

[0012] In formula (1), f 0 、f n are the fundamental frequency and harmonic frequency of the interference signal respectively; A 0 , A n , They are the fundamental wave amplitude, fundamental wave initial phase, harmonic amplitude and harmonic initial phase of the interference signal respectively.

[0013] Furthermore, the standard signal generating unit is used to generate a standard signal with adjustable frequency and amplitude, wherein the standard signal s 1 The specific expression of (t) is:

[0014]

[0015] In formula (2), f p is the standard signal frequency; A p , are the standard signal amplitude and initial phase respectively.

[0016] Furthermore, the adder is used to synthesize the interference signal, the in-phase component and the orthogonal component into an error signal aliased with the interference signal, and the specific formula is:

[0017]

[0018] In formula (3), x 1 (t) is the same direction component, y 1 (t) is the orthogonal component, s 2 (t) is the error signal, k 1 , k 2 is the voltage division coefficient, which is a real number not equal to 0.

[0019] Furthermore, a power amplification unit is used to perform VI control and power amplification on the error signal and the standard signal mixed with the interference signal, and output the difference current and the standard current mixed with the interference signal to the current transformer live calibration device, including:

[0020]

[0021] In formula (4), Δi is the differential current, i p is the standard current, m 1 、m 2is the power amplifier unit VI control coefficient.

[0022] Furthermore, the main control unit is used to read the error value measured by the current transformer live calibration device, and judge whether the current transformer live calibration device is qualified according to the error value, including:

[0023] The overall verification algorithm is used to determine whether the current transformer live calibration device is qualified, and the specific basis for the determination is:

[0024] ΔX=±K 1 (X 1 a 1 +Y 1 a 1 +D x ) (5)

[0025] ΔY=±K 1 (X 1 a 1 +Y 1 a 1 +D y ) (6)

[0026] In formula (5-6), ΔX and ΔY are the basic error allowable values ​​of the in-phase component and quadrature component of the live calibration device respectively; K 1 is the device constant of the live calibration device, is the multiplication factor of the range; X 1 , Y 1 are the absolute values ​​of the ratio difference and phase difference of the live calibration device, respectively, 1 The unit is radian; D x , D y D is the minimum graduation value or quantization value of the live calibration device. y The unit is radian; a 1 It is the accuracy grade of the live calibration device.

[0027] Furthermore, the main control unit is also used for:

[0028] Control the interference signal generating unit and the standard signal generating unit to generate signals with configurable frequency and amplitude;

[0029] The voltage divider is controlled to produce configurable arbitrary common-direction and quadrature errors.

[0030] The present invention also provides a method for checking a live calibration device for a current transformer, comprising:

[0031] Determine the calibration range of the current transformer live calibration device and initialize relevant parameters;

[0032] Configure the current percentage of the calibration point of the calibration range and start the calibration;

[0033] According to the calibration range and the current percentage of the calibration point, the corresponding standard signal generating unit and interference signal generating unit parameters and voltage divider parameters are configured;

[0034] The error value measured by the live calibration device of the current transformer is output, and whether the live calibration device of the current transformer is qualified is judged according to the error value.

[0035] Furthermore, it also includes:

[0036] When all calibration points are calibrated, the calibration range is completed.

[0037] Further, outputting an error value measured by the live calibration device of the current transformer, and judging whether the live calibration device of the current transformer is qualified by the error value, comprises:

[0038] The overall verification algorithm is used to determine whether the current transformer live calibration device is qualified, and the specific basis for the determination is:

[0039] ΔX=±K 1 (X 1 a 1 +Y 1 a 1 +D x ) (5)

[0040] ΔY=±K 1 (X 1 a 1 +Y 1 a 1 +D y ) (6)

[0041] In formula (5-6), ΔX and ΔY are the basic error allowable values ​​of the in-phase component and quadrature component of the live calibration device respectively; K 1 is the device constant of the live calibration device, is the multiplication factor of the range; X 1 , Y 1 are the absolute values ​​of the ratio difference and phase difference of the live calibration device, respectively, 1 The unit is radian; D x , D y D is the minimum graduation value or quantization value of the live calibration device. y The unit is radian; a 1 It is the accuracy grade of the live calibration device.

[0042] The present invention provides a system and method for checking a live calibration device for a current transformer, which can be used to carry out overall calibration of the live calibration device for a current transformer based on the principle of the heterodyne method, and can carry out full-range and fully automatic calibration of live calibration devices for current transformers of different ranges. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 It is a principle block diagram of a system for checking a current transformer live calibration device provided by an embodiment of the present invention;

[0044] Figure 2 It is a flow chart of the overall verification algorithm involved in the embodiment of the present invention. DETAILED DESCRIPTION

[0045] Many specific details are set forth in the following description to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways than those described herein, and those skilled in the art can make similar generalizations without violating the connotation of the present invention, so the present invention is not limited to the specific implementation disclosed below.

[0046] To achieve the above purpose, the present invention creatively proposes a system and method for checking the live calibration device of a current transformer. The basic principle is: first simulate the error current and the adjacent frequency interference current, then synthesize the error current to be measured with the adjacent frequency interference, then output it through power amplification with the standard current, and finally read the error measurement data of the live calibration device of the current transformer, and judge whether the live calibration device of the current transformer is qualified through the overall verification algorithm software.

[0047] The whole system consists of interference signal generating unit, standard signal generating unit, phase shifter, voltage divider, adder, power amplifier unit and main control unit. The principle block diagram is as follows: Figure 1 shown.

[0048] An interference signal generating unit is used to generate an interference signal composed of multiple frequency components with configurable frequency and adjustable amplitude; and transmit the interference signal to an adder;

[0049] A standard signal generating unit, used for generating a standard signal with adjustable frequency and amplitude; transmitting the standard signal to the phase shifter, the voltage divider and the power amplification unit respectively;

[0050] A phase shifter and a voltage divider, used for synthesizing the standard signal into an in-phase component and a quadrature component of an error signal; transmitting the in-phase component and the quadrature component to an adder;

[0051] An adder, used for synthesizing the interference signal, the in-phase component and the orthogonal component into an error signal aliased with the interference signal; and transmitting the error signal to a power amplification unit;

[0052] A power amplification unit, used for performing VI control and power amplification on the error signal and the standard signal mixed with the interference signal, and outputting the difference current and the standard current mixed with the interference signal to the current transformer live calibration device;

[0053] The main control unit is used to read the error value measured by the current transformer live calibration device, and judge whether the current transformer live calibration device is qualified according to the error value.

[0054] Specifically, the interference signal generating unit generates a frequency-configurable and amplitude-adjustable interference signal composed of a plurality of frequency components. Figure 1 Chinese 1 (t) represents, as shown in formula (1):

[0055]

[0056] In formula (1), f 0 、f n They are the fundamental frequency and harmonic frequency of the interference signal, the default is the power frequency 50Hz and 1-20 harmonics, which can be manually configured; A 0 , A n , They are respectively the fundamental amplitude of the interference signal, the fundamental initial phase, the harmonic amplitude, and the harmonic initial phase, which are automatically configured by the overall verification algorithm software.

[0057] The standard signal generating unit generates a standard signal with adjustable frequency and amplitude. Figure 1 Chinese 1 (t) represents, as shown in formula (2):

[0058]

[0059] In formula (2), f p It is the standard signal frequency, the default is 60Hz, which can be manually configured; A p , They are the standard signal amplitude and initial phase, which are automatically configured by the overall verification algorithm software.

[0060] The parameters of the standard signal generating unit and the interference signal generating unit can be configured separately, or the parameters of the standard signal generating unit can be configured first, and then the signal-to-noise ratio parameter SNR can be configured, and then the overall verification algorithm software can automatically generate the interference signal generating unit parameters.

[0061] Phase shifter and voltage divider convert the standard signal s 1 (t) The same-direction component x of the synthetic error signal 1 (t), orthogonal component y 1(t), the adder adds the in-phase component x of the synthesized error signal 1 (t), orthogonal component y 1 (t) and interference signal n 1 (t) Synthesize the error signal s with aliased interference signal 2 (t), as shown in formula (3):

[0062]

[0063] In formula (3), k 1 , k 2 is the voltage division coefficient, which is a real number not equal to 0.

[0064] The main control unit controls the interference signal generating unit and the standard signal generating unit to generate signals with configurable frequency and amplitude, controls the voltage divider to generate configurable arbitrary co-directional error and orthogonal error, reads the error value measured by the current transformer live calibration device, and determines whether the device is qualified through the overall verification software algorithm.

[0065] The judgment basis of the overall verification software algorithm is shown in formula (5-6) (it can also be flexibly configured according to relevant standards).

[0066] ΔX=±K 1 (X 1 a 1 +Y 1 a 1 +D x ) (5)

[0067] ΔY=±K 1 (X 1 a 1 +Y 1 a 1 +D y ) (6)

[0068] In formula (5-6), ΔX and ΔY are the basic error allowable values ​​of the in-phase component and quadrature component of the live calibration device respectively; K 1 is the device constant of the live calibration device, is the multiplication factor of the range; X 1 , Y 1 are the absolute values ​​of the ratio difference and phase difference of the live calibration device, respectively, 1 The unit is radian; D x , D y D is the minimum graduation value or quantization value of the live calibration device. y The unit is radian; a 1 It is the accuracy grade index of the live calibration device divided by 100.

[0069] Based on the same inventive concept, the present invention also provides a method for checking a live calibration device for a current transformer, comprising:

[0070] Determine the calibration range of the current transformer live calibration device and initialize relevant parameters;

[0071] Configure the current percentage of the calibration point of the calibration range and start the calibration;

[0072] According to the calibration range and the current percentage of the calibration point, the corresponding standard signal generating unit and interference signal generating unit parameters and voltage divider parameters are configured;

[0073] The error value measured by the live calibration device of the current transformer is output, and whether the live calibration device of the current transformer is qualified is judged according to the error value.

[0074] Furthermore, it also includes:

[0075] When all calibration points are calibrated, the calibration range is completed.

[0076] Further, outputting an error value measured by the live calibration device of the current transformer, and judging whether the live calibration device of the current transformer is qualified by the error value, comprises:

[0077] The overall verification algorithm is used to determine whether the current transformer live calibration device is qualified, and the specific basis for the determination is:

[0078] ΔX=±K 1 (X 1 a 1 +Y 1 a 1 +D x ) (5)

[0079] ΔY=±K 1 (X 1 a 1 +Y 1 a 1 +D y ) (6)

[0080] In formula (5-6), ΔX and ΔY are the basic error allowable values ​​of the in-phase component and quadrature component of the live calibration device respectively; K 1 is the device constant of the live calibration device, is the multiplication factor of the range; X 1 , Y 1 are the absolute values ​​of the ratio difference and phase difference of the live calibration device, respectively, 1 The unit is radian; D x , D y D is the minimum graduation value or quantization value of the live calibration device. yThe unit is radian; a 1 It is the accuracy grade of the live calibration device.

[0081] The specific working steps of the inspection method for the live calibration device of current transformer are as follows: Figure 2 As shown, the following steps are included:

[0082] Step 1: Manually set the range of the live calibration device to be tested, initialize the parameters, and proceed to the next step;

[0083] Step 2: Configure the current percentage of the first calibration point of the range. The current percentage includes but is not limited to 1%, 5%, 20%, 100%, and 120%, and then proceed to the next step;

[0084] Step 3: Configure the corresponding standard signal generating unit and interference signal generating unit parameters according to the range to be measured and the corresponding current percentage of the calibration point, including configuring f 0 、f n 、f p , A 0 , A n , A p , Or configure f p , A p , SNR, go to the next step;

[0085] Step 4: Configure the voltage divider parameters, including k 1 , k 2 , proceed to the next step;

[0086] Step 5: Control the power amplifier unit to output the differential current ΔI and the standard current I P , proceed to the next step;

[0087] Step 6: Wait for the calibration device to be tested and then proceed to the next step;

[0088] Step 7: Read the calibration device ratio difference X 1 , Phase difference Y 1 , proceed to the next step;

[0089] Step 8: Determine whether all calibration points of the range have been calibrated. If not, proceed to the next step. If completed, proceed to step 10.

[0090] Step 9: Configure the current percentage of the next calibration point in the range. The current percentage includes but is not limited to 1%, 5%, 20%, 100%, and 120%, and then go to step 3;

[0091] Step 10: Process all calibration point data of the range according to formula (5-6), and proceed to the next step after processing;

[0092] Step 11: Output the test results and data.

[0093] The present invention provides a system and method for checking a live calibration device for a current transformer, which can be used to carry out overall calibration of the live calibration device for a current transformer based on the principle of the heterodyne method, and can carry out full-range and fully automatic calibration of live calibration devices for current transformers of different ranges. The overall calibration system of the present invention can provide a technical system guarantee for carrying out new value transfer traceability under real-time working conditions.

[0094] Those skilled in the art will appreciate that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0095] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0096] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0097] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1The steps for the functions specified in one or more boxes.

[0098] Finally, 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 above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents, and any modifications or equivalents that do 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 system for checking a current transformer live calibration device, characterized in that: include: Interference signal generating unit, standard signal generating unit, phase shifter, voltage divider, adder, power amplifier unit and main control unit; An interference signal generating unit is used to generate an interference signal composed of multiple frequency components with configurable frequency and adjustable amplitude; and transmit the interference signal to an adder; A standard signal generating unit, used for generating a standard signal with adjustable frequency and amplitude; Transmitting the standard signal to the phase shifter, the voltage divider and the power amplification unit respectively; A phase shifter and a voltage divider, used for synthesizing the standard signal into an in-phase component and a quadrature component of an error signal; transmitting the in-phase component and the quadrature component to an adder; An adder, used for synthesizing the interference signal, the in-phase component and the orthogonal component into an error signal aliased with the interference signal; and transmitting the error signal to a power amplification unit; A power amplification unit, used for performing VI control and power amplification on the error signal and the standard signal mixed with the interference signal, and outputting the difference current and the standard current mixed with the interference signal to the current transformer live calibration device; The main control unit is used to read the error value measured by the current transformer live calibration device, and judge whether the current transformer live calibration device is qualified according to the error value.

2. The system according to claim 1, characterized in that The interference signal generating unit is used to generate a frequency-configurable and amplitude-adjustable interference signal composed of multiple frequency components, wherein the specific expression of the interference signal n1(t) is: In formula (1), f0, f n are the fundamental frequency and harmonic frequency of the interference signal respectively; A0, A n , They are the fundamental wave amplitude, fundamental wave initial phase, harmonic amplitude and harmonic initial phase of the interference signal respectively.

3. The system according to claim 1, characterized in that The standard signal generating unit is used to generate a standard signal with adjustable frequency and amplitude, wherein the specific expression of the standard signal s1(t) is: In formula (2), f p is the standard signal frequency; A p , are the standard signal amplitude and initial phase respectively.

4. The system according to claim 1, characterized in that The adder is used to synthesize the interference signal, the in-phase component and the orthogonal component into an error signal mixed with the interference signal. The specific formula is: In formula (3), x1(t) is the in-phase component, y1(t) is the orthogonal component, s2(t) is the error signal, k1 and k2 are voltage divider coefficients, and their values ​​are real numbers that are not zero.

5. The system according to claim 1, characterized in that A power amplification unit, used for performing VI control and power amplification on the error signal and the standard signal mixed with the interference signal, and outputting the differential current and the standard current mixed with the interference signal to the current transformer live calibration device, comprising: In formula (4), Δi is the differential current, i p is the standard current, m1 and m2 are the VI control coefficients of the power amplifier unit.

6. The system according to claim 1, characterized in that A main control unit is used to read the error value measured by the current transformer live calibration device, and judge whether the current transformer live calibration device is qualified according to the error value, including: The overall verification algorithm is used to determine whether the current transformer live calibration device is qualified, and the specific basis for the determination is: ΔX=±K1(X1a1+Y1a1+D x ) (5) ΔY=±K1(X1a1+Y1a1+D y ) (6) In formula (5-6), ΔX and ΔY are the basic error allowable values ​​of the in-phase component and quadrature component of the live calibration device, respectively; K1 is the device constant of the live calibration device, which is the multiplication factor of the range; X1 and Y1 are the absolute values ​​of the measured indications of the ratio difference and phase difference of the live calibration device, respectively, and the unit of Y1 is radians; D x , D y D is the minimum graduation value or quantization value of the live calibration device. y The unit is radian; a1 is the accuracy level of the live calibration device.

7. The system according to claim 1, characterized in that The main control unit is also used for: Control the interference signal generating unit and the standard signal generating unit to generate signals with configurable frequency and amplitude; The voltage divider is controlled to produce configurable arbitrary common-direction and quadrature errors.

8. A method for checking a live calibration device for a current transformer, characterized in that: include: Determine the calibration range of the current transformer live calibration device and initialize relevant parameters; Configure the current percentage of the calibration point of the calibration range and start the calibration; According to the calibration range and the current percentage of the calibration point, the corresponding standard signal generating unit and interference signal generating unit parameters and voltage divider parameters are configured; The error value measured by the live calibration device of the current transformer is output, and whether the live calibration device of the current transformer is qualified is judged according to the error value.

9. The method according to claim 8, characterized in that Also includes: When all calibration points are calibrated, the calibration range is completed.

10. The method according to claim 8, characterized in that Outputting an error value measured by a live calibration device for a current transformer, and judging whether the live calibration device for the current transformer is qualified by the error value, including: The overall verification algorithm is used to determine whether the current transformer live calibration device is qualified, and the specific basis for the determination is: ΔX=±K1(X1a1+Y1a1+D x ) (5) ΔY=±K1(X1a1+Y1a1+D y ) (6) In formula (5-6), ΔX and ΔY are the basic error allowable values ​​of the in-phase component and quadrature component of the live calibration device, respectively; K1 is the device constant of the live calibration device, which is the multiplication factor of the range; X1 and Y1 are the absolute values ​​of the measured indications of the ratio difference and phase difference of the live calibration device, respectively, and the unit of Y1 is radians; D x , D y D is the minimum graduation value or quantization value of the live calibration device. y The unit is radian; a1 is the accuracy level of the live calibration device.

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