A kind of whole inspection system and method for current transformer live calibration device

Abstract

The application provides a kind of whole inspection system and method for current transformer live calibration device, comprising: interference signal generating unit, for producing frequency configurable, adjustable interference signal of amplitude;Standard signal generating unit, for producing frequency and adjustable standard signal of amplitude;Phase shifter and voltage divider, for synthesizing the same direction component and quadrature component of error signal of standard signal;Adder, for synthesizing interference signal, same direction component and quadrature component to error signal mixed with interference signal;Power amplifier unit, for carrying out V-I control and power amplification to error signal mixed with interference signal and standard signal, and outputting difference current mixed with interference signal and standard current to live calibration device;Master unit, for reading error value after measurement of live calibration device, and determining whether the live calibration device is qualified by the error value. It can be used for whole verification work of current transformer live calibration device based on the principle of different frequency method.

Description

Technical Field

[0001] This invention relates to the field of current transformer live calibration device verification, and specifically to a system and method for verifying current transformer live calibration devices. Background Technology

[0002] A live-line calibration device for current transformers is a device used to calibrate low-voltage current transformers without power interruption under field operating conditions using a different frequency method (60Hz recommended). Live-line calibration conditions involve 50Hz (which, relative to the calibration 60Hz, represents strong adjacent-channel interference) and its harmonic interference. Therefore, the overall verification device for the live-line calibration device needs to simulate the 50Hz frequency and its harmonics from the field operating conditions as interference signals while simultaneously simulating the error signal. These signals are then mixed and used as the test signal for the live-line calibration device. Currently, there is an urgent need to develop relevant verification systems and methods for this special verification process. Summary of the Invention

[0003] To address the aforementioned technical problems, this invention provides a system for calibrating a current transformer under live conditions, characterized in that it comprises: an interference signal generation unit, a standard signal generation unit, a phase shifter, a voltage divider, an adder, a power amplifier unit, and a main control unit;

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

[0005] A standard signal generation unit is used to generate a standard signal with adjustable frequency and amplitude; the standard signal is then transmitted to a phase shifter, a voltage divider, and a power amplifier unit, respectively.

[0006] Phase shifters and voltage dividers are used to synthesize the same-direction and quadrature components of the error signal from the standard signal; the same-direction and quadrature components are then transmitted to the adder.

[0007] An adder is used to synthesize the interference signal, the in-phase component, and the quadrature component into an error signal mixed with the interference signal; the error signal is then transmitted to the power amplifier unit.

[0008] The power amplification unit is used to perform VI control and power amplification on the error signal and standard signal mixed with interference signals, and output the differential current and standard current mixed with interference signals 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 to determine whether the current transformer live calibration device is qualified based on the error value.

[0010] Furthermore, the interference signal generation 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:

[0011]

[0012] In equation (1), f0 and f n These are the fundamental frequency and harmonic frequency of the interference signal, respectively; A0, A n , These are the fundamental amplitude, fundamental initial phase, harmonic amplitude, and harmonic initial phase of the interference signal, respectively.

[0013] Furthermore, the standard signal generation unit is used to generate a standard signal with adjustable frequency and amplitude, wherein the specific expression of the standard signal s1(t) is:

[0014]

[0015] In equation (2), f p Standard signal frequency; A p , These represent the standard signal amplitude and initial phase, respectively.

[0016] Furthermore, the adder is used to synthesize the interference signal, the in-direction component, and the quadrature component into an error signal mixed with the interference signal, specifically using the following formula:

[0017]

[0018] In equation (3), x1(t) is the same-direction component, y1(t) is the quadrature component, s2(t) is the error signal, and k1 and k2 are voltage divider coefficients, which are real numbers that are not zero.

[0019] Furthermore, the power amplification unit, used for VI control and power amplification of the error signal and standard signal mixed with interference signals, outputs the differential current and standard current mixed with interference signals to the current transformer live calibration device, including:

[0020]

[0021] In equation (4), Δi is the differential current, i p The current is the standard current, and m1 and m2 are the control coefficients of the power amplifier unit VI.

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

[0023] The overall verification algorithm is used to determine whether the current transformer live calibration device is qualified. The specific criteria for the determination are as follows:

[0024] ΔX=±K1(X1a1+Y1a1+D x (5)

[0025] ΔY=±K1(X1a1+Y1a1+D y (6)

[0026] In equation (5-6), ΔX and ΔY are the allowable basic errors of the in-phase and quadrature components of the live calibration device, respectively; K1 is the device constant of the live calibration device, which is the range multiplier; X1 and Y1 are the absolute values ​​of the measured values ​​of the ratio difference and phase difference of the live calibration device, respectively, with Y1 in radians; D x D y D is the minimum scale division or quantization value of the charged calibration device. y The unit is radians; a1 is the accuracy class of the live calibration device.

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

[0028] The interference signal generation unit and the standard signal generation unit are controlled to generate signals with configurable frequency and amplitude.

[0029] The voltage divider can be controlled to generate configurable unidirectional and quadrature errors.

[0030] This invention also provides a method for the inspection of a live calibration device for a current transformer, comprising:

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

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

[0033] Based on the current percentage of the test range and test point, configure the parameters of the corresponding standard signal generation unit and interference signal generation unit, as well as the voltage divider parameters.

[0034] The error value measured by the current transformer live calibration device is used to determine whether the current transformer live calibration device is qualified.

[0035] Furthermore, it also includes:

[0036] Once all calibration points have been calibrated, the calibration range is complete.

[0037] Furthermore, the error value measured by the current transformer live calibration device is used to determine whether the current transformer live calibration device is qualified, including:

[0038] The overall verification algorithm is used to determine whether the current transformer live calibration device is qualified. The specific criteria for the determination are as follows:

[0039] ΔX=±K1(X1a1+Y1a1+D x (5)

[0040] ΔY=±K1(X1a1+Y1a1+D y (6)

[0041] In equation (5-6), ΔX and ΔY are the allowable basic errors of the in-phase and quadrature components of the live calibration device, respectively; K1 is the device constant of the live calibration device, which is the range multiplier; X1 and Y1 are the absolute values ​​of the measured values ​​of the ratio difference and phase difference of the live calibration device, respectively, with Y1 in radians; D x D y D is the minimum scale division or quantization value of the charged calibration device. y The unit is radians; a1 is the accuracy class of the live calibration device.

[0042] The present invention provides a system and method for the overall inspection of a current transformer live calibration device, which can be used to carry out the overall inspection of a current transformer live calibration device based on the principle of different frequency. It can carry out full-range fully automatic inspection of current transformer live calibration devices with different ranges. Attached Figure Description

[0043] Figure 1 This is a schematic block diagram of a testing system for a live calibration device of a current transformer, provided by an embodiment of the present invention.

[0044] Figure 2 This is a flowchart of the overall verification algorithm involved in the embodiments of the present invention. Detailed Implementation

[0045] Numerous specific details are set forth in the following description to provide a full understanding of the invention. However, the invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0046] To achieve the above objectives, this invention creatively proposes a comprehensive inspection system and method for a live-line calibration device of a current transformer. The basic principle is as follows: first, an error current and adjacent-channel interference current are simulated; then, a test error current mixed with adjacent-channel interference is synthesized; then, this current and a standard current are respectively amplified and output; finally, the error measurement data of the live-line calibration device of the current transformer are read, and the overall verification algorithm software determines whether the live-line calibration device of the current transformer is qualified.

[0047] The entire system consists of an interference signal generation unit, a standard signal generation unit, a phase shifter, a voltage divider, an adder, a power amplifier unit, and a main control unit. The block diagram is shown below. Figure 1 As shown.

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

[0049] A standard signal generation unit is used to generate a standard signal with adjustable frequency and amplitude; the standard signal is then transmitted to a phase shifter, a voltage divider, and a power amplifier unit, respectively.

[0050] Phase shifters and voltage dividers are used to synthesize the same-direction and quadrature components of the error signal from the standard signal; the same-direction and quadrature components are then transmitted to the adder.

[0051] An adder is used to synthesize the interference signal, the in-phase component, and the quadrature component into an error signal mixed with the interference signal; the error signal is then transmitted to the power amplifier unit.

[0052] The power amplification unit is used to perform VI control and power amplification on the error signal and standard signal mixed with interference signals, and output the differential current and standard current mixed with interference signals 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 to determine whether the current transformer live calibration device is qualified based on the error value.

[0054] Specifically, the interference signal generating unit generates an interference signal composed of multiple frequency components, with configurable frequency and adjustable amplitude. Figure 1 Let n1(t) be used to represent this, as shown in equation (1):

[0055]

[0056] In equation (1), f0 and f n These are the fundamental frequency and harmonic frequency of the interference signal, respectively. The default is 50Hz (power frequency) and the 1st-20th harmonics, which can be manually configured; A0, A n , These are the fundamental amplitude, fundamental initial phase, harmonic amplitude, and harmonic initial phase of the interference signal, which are automatically configured by the overall verification algorithm software.

[0057] The standard signal generation unit generates one standard signal with adjustable frequency and amplitude. Figure 1 In this context, s1(t) is used to represent the expression, as shown in equation (2):

[0058]

[0059] In equation (2), f p The standard signal frequency is 60Hz by default, but can be manually configured; A p , These 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 generation unit and the interference signal generation unit can be configured separately, or the parameters of the standard signal generation unit can be configured first, followed by the signal-to-noise ratio (SNR) parameter, and then the parameters of the interference signal generation unit can be automatically generated by the overall calibration algorithm software.

[0061] The phase shifter and voltage divider synthesize the standard signal s1(t) into the same-direction component x1(t) and the quadrature component y1(t) of the error signal. The adder synthesizes the same-direction component x1(t) and the quadrature component y1(t) of the synthesized error signal and the interference signal n1(t) into an error signal s2(t) mixed with the interference signal, as shown in Equation (3).

[0062]

[0063] In equation (3), k1 and k2 are the partial pressure coefficients, which are real numbers that are not zero.

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

[0065] The overall verification software algorithm is based on the following criteria (5-6) (or can be flexibly configured with reference to relevant standards).

[0066] ΔX=±K1(X1a1+Y1a1+D x (5)

[0067] ΔY=±K1(X1a1+Y1a1+D y (6)

[0068] In equation (5-6), ΔX and ΔY are the allowable basic errors of the in-phase and quadrature components of the live calibration device, respectively; K1 is the device constant of the live calibration device, which is the range multiplier; X1 and Y1 are the absolute values ​​of the measured values ​​of the ratio difference and phase difference of the live calibration device, respectively, with Y1 in radians; D x D y D is the minimum scale division or quantization value of the charged calibration device. yThe unit is radians; a1 is the accuracy class index of the live calibration device divided by 100.

[0069] Based on the same inventive concept, this invention also provides a method for the inspection and testing of a live calibration device for a current transformer, comprising:

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

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

[0072] Based on the current percentage of the test range and test point, configure the parameters of the corresponding standard signal generation unit and interference signal generation unit, as well as the voltage divider parameters.

[0073] The error value measured by the current transformer live calibration device is used to determine whether the current transformer live calibration device is qualified.

[0074] Furthermore, it also includes:

[0075] Once all calibration points have been calibrated, the calibration range is complete.

[0076] Furthermore, the error value measured by the current transformer live calibration device is used to determine whether the current transformer live calibration device is qualified, including:

[0077] The overall verification algorithm is used to determine whether the current transformer live calibration device is qualified. The specific criteria for the determination are as follows:

[0078] ΔX=±K1(X1a1+Y1a1+D x (5)

[0079] ΔY=±K1(X1a1+Y1a1+D y (6)

[0080] In equation (5-6), ΔX and ΔY are the allowable basic errors of the in-phase and quadrature components of the live calibration device, respectively; K1 is the device constant of the live calibration device, which is the range multiplier; X1 and Y1 are the absolute values ​​of the measured values ​​of the ratio difference and phase difference of the live calibration device, respectively, with Y1 in radians; D x D y D is the minimum scale division or quantization value of the charged calibration device. y The unit is radians; a1 is the accuracy class 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, it includes the following steps:

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

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

[0084] Step 3: Configure the corresponding standard signal generation unit and interference signal generation unit parameters according to the current percentage corresponding to the measurement range and calibration point, including configuring f0, f n f p A0 A n , A p , Or configure f p A p , SNR, proceed to the next step;

[0085] Step 4: Configure the voltage divider parameters, including k1 and k2, and 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 complete the test, then proceed to the next step;

[0088] Step 7: Read the ratio difference X1 and phase difference Y1 of the calibration device, and proceed to the next step;

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

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

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

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

[0093] This invention provides a comprehensive inspection system and method for live calibration devices of current transformers, which can be used to carry out overall verification of live calibration devices of current transformers based on the principle of different frequency methods. It can carry out full-range fully automatic verification of live calibration devices of current transformers with different ranges. The overall verification system of this invention can provide technical system support for carrying out new value transfer and traceability under real-time operating conditions.

[0094] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied 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] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0096] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0097] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function 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 and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of the claims of the present invention.

Claims

1. A system for calibrating a current transformer under live conditions, characterized in that, include: Interference signal generation unit, standard signal generation unit, phase shifter, voltage divider, adder, power amplifier unit, and main control unit; An interference signal generating unit is used to generate a frequency-configurable and amplitude-adjustable interference signal composed of multiple frequency components; and to transmit the interference signal to an adder. A standard signal generation unit is used to generate standard signals with adjustable frequency and amplitude. The standard signal is transmitted to the phase shifter, voltage divider, and power amplifier unit, respectively. Phase shifters and voltage dividers are used to synthesize the same-direction and quadrature components of the error signal from the standard signal; the same-direction and quadrature components are then transmitted to the adder. An adder is used to synthesize the interference signal, the in-phase component, and the quadrature component into an error signal mixed with the interference signal; the error signal is then transmitted to the power amplifier unit. The power amplification unit is used to perform VI control and power amplification on the error signal and standard signal mixed with interference signals, and output the differential current and standard current mixed with interference signals 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 to determine whether the current transformer live calibration device is qualified based on the error value.

2. The system according to claim 1, characterized in that, The interference signal generation unit is used to generate a frequency-configurable and amplitude-adjustable interference signal composed of multiple frequency components. The specific expression for the interference signal n1(t) is as follows: In equation (1), f0 and f n These are the fundamental frequency and harmonic frequency of the interference signal, respectively; A0, A n , These are the fundamental amplitude, fundamental 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 generation unit is used to generate standard signals with adjustable frequency and amplitude. The specific expression of the standard signal s1(t) is as follows: In equation (2), f p Standard signal frequency; A p , These represent 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 quadrature component into an error signal mixed with the interference signal. The specific formula is as follows: In equation (3), x1(t) is the same-direction component, y1(t) is the quadrature component, s2(t) is the error signal, and k1 and k2 are voltage divider coefficients, which are real numbers that are not zero.

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

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

7. The system according to claim 1, characterized in that, The main control unit is also used for: The interference signal generation unit and the standard signal generation unit are controlled to generate signals with configurable frequency and amplitude. The voltage divider can be controlled to generate configurable unidirectional and quadrature errors.

8. A method for inspecting 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 the relevant parameters; Configure the current percentage at the calibration point of the calibration range and start the calibration; Based on the current percentage of the test range and test point, configure the parameters of the corresponding standard signal generation unit and interference signal generation unit, as well as the voltage divider parameters. The error value measured by the current transformer live calibration device is used to determine whether the current transformer live calibration device is qualified.

9. The method according to claim 8, characterized in that, Also includes: Once all calibration points have been calibrated, the calibration range is complete.

10. The method according to claim 8, characterized in that, The error value measured by the live calibration device of the output current transformer is used to determine whether the live calibration device of the current transformer is qualified, including: The overall verification algorithm is used to determine whether the current transformer live calibration device is qualified. The specific criteria for the determination are as follows: ΔX = ±K1(X1a1+ Y1a1+ D x ) (5) ΔY=±K1(X1a1+Y1a1+D y ) (6) In equation (5-6), ΔX and ΔY are the allowable basic errors of the in-phase and quadrature components of the live calibration device, respectively; K1 is the device constant of the live calibration device, which is the range multiplier; X1 and Y1 are the absolute values ​​of the measured values ​​of the ratio difference and phase difference of the live calibration device, respectively, with Y1 in radians; D x D y D is the minimum scale division or quantization value of the charged calibration device. y The unit is radians; a1 is the accuracy class of the live calibration device.

Images