CN217468179U - Error compensation device for standard voltage transformer - Google Patents
Error compensation device for standard voltage transformer Download PDFInfo
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- CN217468179U CN217468179U CN202220865032.8U CN202220865032U CN217468179U CN 217468179 U CN217468179 U CN 217468179U CN 202220865032 U CN202220865032 U CN 202220865032U CN 217468179 U CN217468179 U CN 217468179U
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Abstract
The utility model provides a standard voltage transformer technical field's a standard voltage transformer error compensation arrangement, include: a voltage input channel; a current input channel; the MCU control module is connected with the voltage input channel and the current input channel; the phase shift circuit is connected with the voltage input channel; the first digital-to-analog conversion chip is connected with the voltage input channel, and the digital control end is connected with the MCU control module; the second digital-to-analog conversion chip is connected with the phase-shifting circuit, and the digital control end is connected with the MCU control module; the addition circuit is connected with the first digital-to-analog conversion chip and the second digital-to-analog conversion chip; the error voltage signal isolation module is connected with the addition circuit; and the display screen is connected with the MCU control module. The utility model has the advantages that: the floating signal corresponding to the voltage transformer error can be generated according to the voltage transformer error, the floating signal can be used for compensating the output of the voltage transformer, and the accuracy grade of the voltage transformer is greatly improved.
Description
Technical Field
The utility model relates to a standard voltage transformer technical field indicates a standard voltage transformer error compensation device very much.
Background
Voltage transformers are similar to transformers and are used to transform the voltage on the line. However, the purpose of the transformer to transform the voltage is to deliver electrical energy, and the purpose of the voltage transformer to transform the voltage is to measure the voltage of the line.
Because the electromagnetic voltage transformer has exciting current and the primary winding has resistance and leakage reactance, the exciting current generates voltage drop on the impedance, thereby inevitably causing no-load error of the voltage transformer; when the load is connected to the secondary winding, a load current is generated in the secondary winding, a load current component is added to the primary winding to keep the magnetic flux constant, and the internal impedance of the primary winding and the secondary winding is similarly dropped by the load current due to the resistance and the leakage reactance of the secondary winding, so that the load error of the voltage transformer is formed.
The voltage transformer error, also called as the voltage transformer ratio error, includes a ratio difference and a phase difference, wherein the ratio difference is also called as the ratio difference, which is caused by the fact that the actual voltage ratio is not equal to the rated voltage ratio, and is generally expressed by a percentage (%); the phase difference is also called angular difference, and refers to the phase difference between the primary voltage and the secondary voltage phasor, and is generally expressed by a minute (') or a centimeter arc (crad). The error of a voltage transformer can be represented by a complex number epsilon ═ f + j delta, where f is called the specific difference and delta is called the angular difference.
Because the exciting current of the iron core of the electromagnetic voltage transformer has nonlinearity, the error of a single-stage voltage transformer above 10kV is difficult to break through from 0.01 level to 0.02 level, and the nonlinearity error of the voltage transformer can be further reduced by a two-stage structure compensation method in the prior art, but in the transformers with high voltage levels, insulation and shielding structures and the like bring challenges. Moreover, the mutual inductor with the same voltage class inevitably brings increase of volume and weight, and simultaneously increases economic cost.
Therefore, if the standard voltage transformer error compensation device can be provided, the accuracy grade of the voltage transformer can be effectively improved on the basis of not changing the structure of the original voltage transformer, and the accuracy requirement of a user on the standard voltage transformer can be greatly met.
Disclosure of Invention
The to-be-solved technical problem of the utility model lies in providing a standard voltage transformer error compensation device, realizes promoting voltage transformer's the degree of accuracy grade.
The utility model provides a standard voltage transformer error compensation arrangement, include:
a voltage input channel;
a current input channel;
the input end of the MCU control module is connected with the output ends of the voltage input channel and the current input channel;
the input end of the phase shift circuit is connected with the output end of the voltage input channel;
the input end of the first digital-to-analog conversion chip is connected with the output end of the voltage input channel, and the digital control end of the first digital-to-analog conversion chip is connected with the MCU control module;
the input end of the second digital-to-analog conversion chip is connected with the phase-shifting circuit, and the digital control end of the second digital-to-analog conversion chip is connected with the MCU control module;
the input end of the addition circuit is connected with the output ends of the first digital-to-analog conversion chip and the second digital-to-analog conversion chip;
the input end of the error voltage signal isolation module is connected with the output end of the addition circuit;
the display screen is connected with the MCU control module;
and the power supply module is respectively connected with the MCU control module, the error voltage signal isolation module and the display screen.
Further, the voltage input channel includes:
a first double-stage isolation voltage transformer;
and the input end of the filtering amplification circuit is connected with the secondary output voltage end of the first double-stage isolation voltage transformer, and the output end of the filtering amplification circuit is connected with the MCU control module, the phase shift circuit and the first digital-to-analog conversion chip.
Further, the current input channel includes:
a sampling resistor;
and the input end of the first filter circuit is connected with two ends of the sampling resistor, and the output end of the first filter circuit is connected with the MCU control module.
Further, the MCU control module includes:
the singlechip is respectively connected with the first digital-to-analog conversion chip, the second digital-to-analog conversion chip, the display screen and the power module;
one end of the double-channel AD signal acquisition module is connected with the singlechip, and the other end of the double-channel AD signal acquisition module is connected with the voltage input channel and the current input channel;
the storage module is connected with the single chip microcomputer;
and the RS232 interface is connected with the singlechip.
Further, the error voltage signal isolation module includes:
the input end of the second filter circuit is connected with the output end of the addition circuit;
the input end of the amplifying circuit is connected with the output end of the second filter circuit;
and the high end of the primary side of the second double-stage isolation voltage transformer is connected with the output end of the amplifying circuit and the input end of the second filter circuit, and the low end of the primary side of the second double-stage isolation voltage transformer is grounded.
The utility model has the advantages of:
since the error curve of each standard voltage transformer when leaving the factory is a basically determined parameter and is relatively stable, the error value is mainly related to the current working voltage and the current of the load. Therefore, by setting the error table or the error function analytic formula of the storage module for storing the standard voltage transformer, the single chip microcomputer respectively collects the secondary voltage signal of the voltage transformer in the voltage input channel and the load current signal of the voltage transformer in the current input channel in real time, obtains the corresponding error coefficient according to the current working voltage and the load current, generates the corresponding error signal of the voltage transformer based on the error coefficient, and outputs the corresponding floating error compensation voltage signal through the error voltage signal isolation module, namely generates the corresponding error floating signal of the voltage transformer according to the error value of the voltage transformer, so as to compensate the output of the voltage transformer, thereby realizing that the accuracy grade of the voltage transformer is greatly improved on the basis of not changing the original structure of the voltage transformer.
Drawings
The invention will be further described with reference to the following examples with reference to the accompanying drawings.
Fig. 1 is a schematic circuit diagram of the error compensation device of the standard voltage transformer of the present invention.
Fig. 2 is a schematic circuit diagram of the error compensation device for a standard voltage transformer of the present invention.
Fig. 3 is a flow chart of the working principle of the present invention.
Fig. 4 is a schematic flow chart of the storage error coefficient of the present invention.
Fig. 5 is a schematic flow chart of the present invention for reading error coefficients.
Fig. 6 is a wiring diagram of the usage state of the present invention.
Description of the labeling:
100-a standard voltage transformer error compensation device, 1-a voltage input channel, 2-a current input channel, 3-an MCU control module, 4-a phase shift circuit, 5-a first digital-to-analog conversion chip, 6-a second digital-to-analog conversion chip, 7-an addition circuit, 8-an error voltage signal isolation module, 9-a display screen, 10-a power module, 11-a first double-stage isolation voltage transformer, 12-a filtering amplification circuit, 21-a sampling resistor, 22-a first filter circuit, 31-a single chip microcomputer, 32-a double-channel AD signal acquisition module, 33-a storage module, 34-an RS232 interface, 81-a second filter circuit, 82-an amplification circuit and 83-a second double-stage isolation voltage transformer.
Detailed Description
The technical scheme in the embodiment of the application has the following general idea: the storage module 33 is arranged for storing an error table of the standard single-stage voltage transformer, error values of the voltage signal and the current signal which are collected by the single chip microcomputer 31 in real time and a preset value are respectively compared, corresponding error coefficients are inquired by using the error values and the error table, corresponding voltage transformer error floating signals are generated based on the error coefficients, corresponding compensation error voltage signals are output based on the voltage transformer error floating signals, then the output of the standard single-stage voltage transformer is compensated, and the accuracy of the standard single-stage voltage transformer is improved on the basis that the original structure of the voltage transformer is not changed.
Referring to fig. 1 to 6, a preferred embodiment of an error compensation apparatus 100 for a standard voltage transformer of the present invention includes:
a voltage input channel 1 for connecting the output voltage of a voltage transformer (not shown) to be compensated;
the current input channel 2 is used for accessing the load current of the voltage transformer to be compensated;
the input end of the MCU control module 3 is connected with the output ends of the voltage input channel 1 and the current input channel 2, and is used for collecting the voltage signal output by the voltage input channel 1 and the current signal output by the current input channel 2 and controlling the work of the error compensation device 100;
the input end of the phase shift circuit 4 is connected with the output end of the voltage input channel 1 and is used for shifting the phase of an input voltage signal;
the input end of the first digital-to-analog conversion chip 5 is connected with the output end of the voltage input channel 1, and the digital control end of the first digital-to-analog conversion chip is connected with the MCU control module 3 and used for performing analog-to-digital conversion on an input voltage signal;
the input end of the second digital-to-analog conversion chip 6 is connected with the phase-shifting circuit 4, and the digital control end of the second digital-to-analog conversion chip is connected with the MCU control module 3 and is used for performing analog-to-digital conversion on an input voltage signal;
an adding circuit 7, an input end of which is connected with the output ends of the first digital-to-analog conversion chip 5 and the second digital-to-analog conversion chip 6, for overlapping the voltage signals output by the first digital-to-analog conversion chip 5 and the second digital-to-analog conversion chip 6;
the input end of the error voltage signal isolation module 8 is connected with the output end of the addition circuit 7 and is used for producing a floating error voltage signal after the error voltage signal is isolated;
the display screen 9 is connected with the MCU control module 3 and used for operating the error compensation device 100 and setting an error coefficient;
and the power supply module 10 is respectively connected with the MCU control module 3, the error voltage signal isolation module 8 and the display screen 9 and is used for supplying power to the error compensation device 100.
The voltage input channel 1 includes:
a first double-stage isolation voltage transformer 11, the input signal of which is the output voltage of the voltage transformer to be compensated;
and the input end of the filtering and amplifying circuit 12 is connected with the secondary output voltage end of the first double-stage isolation voltage transformer 11, and the output end of the filtering and amplifying circuit is connected with the MCU control module 3, the phase-shifting circuit 4 and the first digital-to-analog conversion chip 5, and is used for filtering and amplifying the input voltage signal.
The current input channel 2 includes:
a sampling resistor 21;
and the input end of the first filter circuit 22 is connected with two ends of the sampling resistor 21, and the output end of the first filter circuit is connected with the MCU control module 3 and used for filtering an input current signal.
The MCU control module 3 includes:
a single chip microcomputer 31, which is respectively connected to the first digital-to-analog conversion chip 5, the second digital-to-analog conversion chip 6, the display screen 9 and the power module 10, and is used for controlling the operation of the error compensation apparatus 100, when the error compensation apparatus is implemented specifically, only a single chip microcomputer capable of realizing the function is selected from the prior art, and the type is not limited to what type, for example, a single chip microcomputer of STM32F103 series of ST corporation, and the control program is well known to those skilled in the art, which can be obtained by those skilled in the art without creative work;
a dual-channel AD signal acquisition module 32, one end of which is connected to the single chip 31 and the other end of which is connected to the voltage input channel 1 and the current input channel 2, with a sampling time interval set to 1 second;
the storage module 33 is connected with the singlechip 31 and used for storing an error table;
and the RS232 interface 34 is connected with the singlechip 31 and is used for communicating the error compensation device 100 with the outside.
The error voltage signal isolation module 8 includes:
a second filter circuit 81, the input end of which is connected with the output end of the adder circuit 7;
an amplifying circuit 82, the input end of which is connected to the output end of the second filter circuit 81, for compensating the output voltage signal;
a second double-stage isolation voltage transformer 83, the high side of the primary side is connected to the output terminal of the amplifying circuit 82 and the input terminal of the second filter circuit 81, and the low side of the primary side is grounded; the output voltage of the second double-stage isolation voltage transformer 83 is the ratio of the input voltage of the first double-stage isolation voltage transformer 11, when the input voltage and the input current are not changed, the output voltage of the second double-stage isolation voltage transformer 83 is constant, and when different phases and amplitudes are needed, the in-phase component value and the quadrature component value are adjusted.
The working principle of the utility model comprises the following steps:
step S10, inputting error values (including a specific difference and an angular difference) of the standard voltage transformer under different working voltages and different load currents into the single chip microcomputer through an RS232 interface or a display screen, and storing the received error values into an error table in a storage module by the single chip microcomputer;
step S20, the input voltage is input into a dual-channel AD signal acquisition module after passing through a first two-stage isolation voltage transformer and a filtering and amplifying circuit, and an in-phase component signal and an orthogonal component signal are separated out through a phase-shifting circuit and serve as reference signals of an in-phase component and an orthogonal component of an error signal;
step S30, inputting the input current to a dual-channel AD signal acquisition module after the input current passes through a sampling resistor and a filter circuit;
step S40, the single chip microcomputer obtains a voltage value and a current value through a dual-channel AD signal acquisition module, obtains an error coefficient based on the voltage value and the current value, and generates digital control quantities of a first digital-to-analog conversion chip and a second digital-to-analog conversion chip, wherein the digital control quantities are used for controlling the sizes of an in-phase component and an orthogonal component of an error signal; the error coefficients are amplitude coefficients and phase coefficients of the output signals relative to the input signals;
the error coefficient is subdivided into 500 groups of data according to different input voltages and input currents; the input voltage range is 10% -130% of 100V or 100/√ 3V, one voltage data is stored in every 5 (+/-2.5) percentage points, and the data of 25 packets is stored at most; the input current range is 0-100 mA, one group of current data is stored every 5 (+ -2.5) mA, at most 20 packets of data are stored, and 500 groups of data are correspondingly stored in the transverse direction and the longitudinal direction of the voltage and the current.
Step S50, the adder circuit combines the in-phase component of the error signal output by the first D/A converter chip and the quadrature component of the error signal output by the second D/A converter chip into an error voltage signal;
and step S60, the error voltage signal output by the addition circuit is output by the filter circuit, the amplifying circuit and the second double-stage isolation voltage transformer to generate a floating error compensation signal corresponding to the input voltage and the input current.
In step S40, the error coefficients include amplitude coefficients and phase coefficients.
The unit of the amplitude coefficient and the phase coefficient is 1 multiplied by 10 respectively -6 And 1 micro radian with resolution of 1 × 10 -6 (ii) a Input voltage of the first double-stage isolation voltage transformer: 0-200V; input current of the current-voltage conversion module: 0-100 mA; output voltage of the second two-stage isolation voltage transformer: 0-0.1V, and the maximum error is +/-0.2%.
In step S40, the obtaining an error coefficient based on the voltage value and the current value is specifically:
and respectively comparing the voltage value with the current value to a preset error table in a storage module, and searching a corresponding error value based on the error table.
In step S40, the obtaining an error coefficient based on the voltage value and the current value is specifically:
and inputting the voltage value and the current value into a preset error function analytical formula to calculate an error value, wherein the formula of the error function analytical formula is epsilon (V, I). The storage module can store error functions of a plurality of voltage transformers and correspond to the voltage transformers with different numbers, namely the error compensation device of the same standard voltage transformer can be matched with a plurality of standard voltage transformers for use.
The utility model discloses an experimental verification process as follows:
(1) voltage access A, X terminal (voltage input channel);
(2) the current is connected into an I + and an I-terminal (a current input channel);
(3) adjusting a voltage dial indicator, clicking a modification button, setting an arbitrary value between 0 and 1000PPM according to the size of the dial indicator and the current, clicking to store, storing the data to a fixed address after waiting for 2 seconds, and calling out the stored corresponding data when the voltage and the current reach the same size next time;
(4) the dial indicator stores one data every 5 (+ -2.5) percentage points from 10-130% storage intervals, and stores 25 packets of data at most; the current is saved at an interval of 0-100 mA, one group of data is saved at 5 (+ -2.5) mA, the data of at most 20 packets is saved, and the voltage and the current correspond to 500 groups of data in the transverse direction and the longitudinal direction;
(5) the floating error voltage signal is output from the U + and U-binding posts;
(6) the output end of the compensated voltage transformer is converted into a' 0 、x' 0 。
The experimental transformer is two-stage voltage transformers with the voltage level of 10kV (# 1: model: HJS158, No. 1708051; # 2: model: HJS, No. 8209), and the accuracy level is 0.01 level.
High-end difference measurement mode, direct comparison measurement:
two 10kV voltage transformers are directly compared and measured in a high-end difference measurement mode, and error measurement data are shown in the following table:
after the voltage transformer is cascaded with an error signal generation module, comparing and measuring (high-end measuring difference):
the voltage transformer cascade error signal generation module is schematically wired, the transformer secondary output is connected to the voltage access A, X terminal of the module, and the current input is connected in series from the low end of the voltage transformer secondary output, as shown in fig. 6. After cascading, the output end of the mutual inductor is converted into a' 0 、x' 0 。
Note: the unit of the orthogonal component in the error reading of the mutual inductor calibrator is divided, and the unit of the orthogonal component in the error module is urad, and one-time unit transformation is required.
(1) Connection mode I, #2 mutual inductor proportional output cascade error module (linear correction relative to comparative output)
The proportional output of the #2 transformer is connected to a voltage access A, X binding post of the module; the current wiring terminal (I + and I-) is suspended; the error signal output U + is connected with the high end of the proportional output of the #2 mutual inductor, and the error signal output U-is connected with the difference measurement input end K of the calibrator; the calibrator is in power supply connection with the excitation output of the #2 mutual inductor; the input end D of the error measurement of the calibrator is connected with the high-end of the proportional output of the #1 mutual inductor; and the low end of the proportional output of the #1 transformer is in short circuit with the low end of the proportional output of the #2 transformer.
Comparing experimental data before and after correction:
connection mode one, #2 mutual inductor excitation output cascade error module (linear correction for excitation output)
The excitation output of the #2 mutual inductor is connected to a voltage access A, X binding post of the module; the current wiring terminal (I + and I-) is suspended; the error signal output U + is connected with the high end of the excitation output of the #2 mutual inductor, and the error signal output U-is connected with the difference measurement input end K of the calibrator; the calibrator is in power supply connection with the excitation output of the #2 mutual inductor; the input end D of the error measurement of the calibrator is connected with the high-end of the proportional output of the #1 mutual inductor; and the low end of the proportional output of the #1 transformer is in short circuit with the low end of the proportional output of the #2 transformer.
Comparing experimental data before and after correction:
note: analysis of the cause of the jitter in the readings after replenishment: (1) the grounding of the experimental environment is not good, and the ground signal is interfered; (2) the output signal of the error module is shielded by a shielding wire, so that the interference is reduced; (3) the high-voltage power supply has certain interference, namely, a secondary signal output by the mutual inductor is not a clean sinusoidal signal.
To sum up, the utility model has the advantages that:
since the error curve of each standard voltage transformer when leaving the factory is a basically determined parameter and is relatively stable, the error value is mainly related to the current working voltage and the current of the load. Therefore, by setting the error table or the error function analytic formula of the storage module for storing the standard voltage transformer, the single chip microcomputer respectively collects the secondary voltage signal of the voltage transformer in the voltage input channel and the load current signal of the voltage transformer in the current input channel in real time, obtains the corresponding error coefficient according to the current working voltage and the load current, generates the corresponding error signal of the voltage transformer based on the error coefficient, and outputs the corresponding floating error compensation voltage signal through the error voltage signal isolation module, namely generates the corresponding error floating signal of the voltage transformer according to the error value of the voltage transformer, so as to compensate the output of the voltage transformer, thereby realizing that the accuracy grade of the voltage transformer is greatly improved on the basis of not changing the original structure of the voltage transformer.
Although specific embodiments of the invention have been described herein, it will be understood by those skilled in the art that the specific embodiments described are illustrative only and are not limiting upon the scope of the invention, as equivalent modifications and variations within the spirit of the invention are intended to be covered by the appended claims.
Claims (5)
1. The utility model provides a standard voltage transformer error compensation arrangement which characterized in that: the method comprises the following steps:
a voltage input channel;
a current input channel;
the input end of the MCU control module is connected with the output ends of the voltage input channel and the current input channel;
the input end of the phase shift circuit is connected with the output end of the voltage input channel;
the input end of the first digital-to-analog conversion chip is connected with the output end of the voltage input channel, and the digital control end of the first digital-to-analog conversion chip is connected with the MCU control module;
the input end of the second digital-to-analog conversion chip is connected with the phase-shifting circuit, and the digital control end of the second digital-to-analog conversion chip is connected with the MCU control module;
the input end of the addition circuit is connected with the output ends of the first digital-to-analog conversion chip and the second digital-to-analog conversion chip;
the input end of the error voltage signal isolation module is connected with the output end of the addition circuit;
the display screen is connected with the MCU control module;
and the power supply module is respectively connected with the MCU control module, the error voltage signal isolation module and the display screen.
2. A standard voltage transformer error compensation arrangement as claimed in claim 1, wherein: the voltage input channel includes:
a first double-stage isolation voltage transformer;
and the input end of the filtering amplification circuit is connected with the secondary output voltage end of the first double-stage isolation voltage transformer, and the output end of the filtering amplification circuit is connected with the MCU control module, the phase shift circuit and the first digital-to-analog conversion chip.
3. A standard voltage transformer error compensation arrangement as claimed in claim 1, wherein: the current input channel includes:
a sampling resistor;
and the input end of the first filter circuit is connected with two ends of the sampling resistor, and the output end of the first filter circuit is connected with the MCU control module.
4. A standard voltage transformer error compensation arrangement as claimed in claim 1, wherein: the MCU control module includes:
the singlechip is respectively connected with the first digital-to-analog conversion chip, the second digital-to-analog conversion chip, the display screen and the power module;
one end of the double-channel AD signal acquisition module is connected with the single chip microcomputer, and the other end of the double-channel AD signal acquisition module is connected with the voltage input channel and the current input channel;
the storage module is connected with the single chip microcomputer;
and the RS232 interface is connected with the singlechip.
5. A standard voltage transformer error compensation arrangement as claimed in claim 1, wherein: the error voltage signal isolation module includes:
the input end of the second filter circuit is connected with the output end of the addition circuit;
the input end of the amplifying circuit is connected with the output end of the second filter circuit;
and the high end of the primary side of the second double-stage isolation voltage transformer is connected with the output end of the amplifying circuit and the input end of the second filter circuit, and the low end of the primary side of the second double-stage isolation voltage transformer is grounded.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202220865032.8U CN217468179U (en) | 2022-04-15 | 2022-04-15 | Error compensation device for standard voltage transformer |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202220865032.8U CN217468179U (en) | 2022-04-15 | 2022-04-15 | Error compensation device for standard voltage transformer |
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| CN217468179U true CN217468179U (en) | 2022-09-20 |
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