CN108279396A - Anti- DC component current transformer error tester and its test method - Google Patents
Anti- DC component current transformer error tester and its test method Download PDFInfo
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- CN108279396A CN108279396A CN201810356222.5A CN201810356222A CN108279396A CN 108279396 A CN108279396 A CN 108279396A CN 201810356222 A CN201810356222 A CN 201810356222A CN 108279396 A CN108279396 A CN 108279396A
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- G—PHYSICS
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- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R35/00—Testing or calibrating of apparatus covered by the other groups of this subclass
- G01R35/02—Testing or calibrating of apparatus covered by the other groups of this subclass of auxiliary devices, e.g. of instrument transformers according to prescribed transformation ratio, phase angle, or wattage rating
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Abstract
The present invention relates to Electric Energy Metering Technology fields, it is a kind of anti-DC component current transformer error tester and its test method, the former includes shell, anti-DC component current transformer test circuit and data processing unit, the anti-DC component current transformer test circuit and data processing unit are arranged in shell, and anti-DC component current transformer test circuit includes pressure regulator, current lifting device, the first rectifier diode, the second rectifier diode, current-limiting resistance, the first half-wave current sampling resistor, second half-wave current sampling resistor etc..The present invention is flowed up using pressure regulator and current lifting device, half-wave current is exported using diode rectification, half-wave current and mutual inductor secondary current are sampled using measuring resistance, simple and reliable amplifying circuit and high-resolution A/D sample conversions module are used, obtains the ratio error and phase error of fundamental wave.Since circuit design is reasonable, it is accurate to calculate, and the accuracy of device and stability are all protected.
Description
Technical field
It is a kind of anti-DC component current transformer error tester and its survey the present invention relates to Electric Energy Metering Technology field
Method for testing, full name are based on the anti-DC component current transformer error tester and its test method under halfwave rectifier.
Background technology
Electric energy meter is the important measurement instrument in electric energy metering device, country using electric energy meter as mandatory calibrating project,
It needs according to JJG596-2012《Electronic type AC energy meter vertification regulation》To its gauging error；But calibrating project can not
Cover all working state of electric energy meter.In GB/T 17215.321-2008《Exchange electrical measuring device, particular/special requirement, the 21st
Point, state type active electric energy meter (1 grade and 2 grades)》In specify that halfwave rectifier to the limit value of the influence amount of electric energy meter error, provides
Half wave rectification testing line and direct current and each harmonic content.Direct access state type active energy is determined by experiment
For table when passing through half-wave rectified current, it is negative error that error, which obviously increases, and is wanted without reference to GB/T17215.321-2008
Electric energy meter error under asking can be more than even -50% or more, and very big loss is caused to electrical energy measurement.By testing clear half
It is sampling Current Transformer that wave rectified current, which measures electric energy meter and generates the critical component of significant impact, meets prescribed requirement
The current transformer installed in electric energy meter error under half-wave rectified current is not more than ± 3%, and angular difference is not more than ± 500 '.It is this
Can satisfactory current transformer be commonly referred to as anti-DC component current transformer.There is no one on domestic market
Mature technology is planted to measure error of the anti-DC component current transformer under half-wave current, so that electric energy meter manufacturer is only
It can be confirmed whether to meet the requirements by the test circuit of standard offer after installation, checkability is low.If occur due to
Electrical energy measurement loss is very big caused by the reason of mutual inductor quality.
Invention content
The present invention provides a kind of anti-DC component current transformer error tester based under halfwave rectifier and its surveys
Method for testing overcomes the deficiency of the above-mentioned prior art, and can effectively solve existing device cannot be used for measuring anti-DC component
Error under the half-wave current of current transformer, can only installation electric energy meter complete after by standard provide test circuit come
It is confirmed whether to meet the requirements, there is a problem of that checkability is low.
One of technical scheme of the present invention is realized by following measures：This is based on the anti-direct current under halfwave rectifier point
It includes shell, anti-DC component current transformer test circuit and data processing unit, institute to measure current transformer error tester
It states anti-DC component current transformer test circuit and data processing unit is arranged in shell, anti-DC component Current Mutual Inductance
Device test circuit includes pressure regulator, current lifting device, the first rectifier diode, the second rectifier diode, current-limiting resistance, the first half-wave electricity
Flow sampling resistor, the second half-wave current sampling resistor, the external AC power of input terminal of the pressure regulator, the output end of pressure regulator
Connect respectively with the first binding post of current lifting device and the second binding post, current lifting device third binding post respectively with the first rectification two in parallel
The anode of pole pipe is connected with the cathode of the second rectifier diode, and the 4th binding post of current lifting device is connect with current-limiting resistance, current-limiting resistance
External build-out resistor, first the first binding post of half-wave current sampling resistor and are connected between the first rectifier diode cathode
Two rectifier diode anodes connect, and data processing unit includes A/D sample conversions module, data processing module and ARM modules, A/
D sample conversion modules are connect with data processing module, and ARM modules obtain the basic test information for being detected current transformer, ARM moulds
The tested current transformer basic test information of input is sent to data processing module by block.
Here is the further optimization and/or improvements to foregoing invention technical solution：
External trace to the source the first binding post of interface and external the second wiring of interface of tracing to the source are additionally provided on above-mentioned hull outside face
Column, first half-wave current sampling resistor second and third binding post be connected to it is external trace to the source on the first binding post of interface, the second half-wave electricity
Stream sampling resistor two binding posts be both connected to it is external trace to the source on the second binding post of interface, external the first binding post of interface of tracing to the source
It is connect with A/D sample conversion modules with external the second binding post of interface of tracing to the source.
Above-mentioned external trace to the source is connected with the amplification of the first controllable gain between the first binding post of interface and A/D sample conversion modules
Device, external trace to the source are connected with the second controllable gain amplifier between the second binding post of interface and A/D sample conversion modules.
Above-mentioned further includes communication module and host computer, and host computer is connect with ARM modules by communication module.
Above-mentioned further includes keyboard and display, and keyboard and display are connect with ARM modules.
Above-mentioned further includes data storage, and data storage is connect with ARM modules.
Above-mentioned to be additionally provided with radiation panel, radiation panel is fixedly mounted on and the first half-wave current sampling resistor and the second half
On the metal base plate of the corresponding housing bottom in wave current sampling resistor position.
Technical scheme of the present invention second is that being realized by following measures：It is a kind of above-mentioned based on anti-under halfwave rectifier
The test method of DC component current transformer error tester, includes the following steps：
Step 1, primary current, secondary current and the secondary load of anti-DC component current transformer are set；
Step 2, the half-wave current that current transformer is acquired by the first half-wave current sampling resistor R1, passes through second
Half-wave current sampling resistor R2 measures secondary current, and measuring signal passes through 1 to 64 times of the first controllable gain amplifier and second
Be synchronized to A/D sample conversion module ports after controllable gain amplifier amplification so that measuring signal in 1.2V between 2.5V, peak
Threshold voltage is less than 4V, in the linearly interval of A/D sample conversion modules；
Step 3, it controls A/D sample conversions module using data processing module and 512 point sampling of complete cycle wave is carried out to signal, obtain
To discrete digital signal, i.e., the mathematics model analysis that the first half-wave current passes through current transformer：First half-wave current is one
Non-sinusoid, the first half-wave current generate half-wave voltage by the first half-wave current sampling resistor, use A/D sample conversion modules
Measurement obtains discrete voltage, and DC component, fundametal compoment and each even-order harmonic component is calculated by Fourier FFT
Current value, full-wave electric current virtual value is the first half-wave current virtual valueTimes, the first half-wave current becomes through electric current Fourier
Time-domain expression after alternatively is：
Wherein the 45% of DC current accounting full-wave electric current, 50%, the 100Hz electric currents of fundamental current accounting full-wave electric current are about
The 23% of accounting fundamental current, also other even-order harmonic electric currents are also proportional；The virtual value of half-wave current is equal to each of it
The square root of the virtual value quadratic sum of order harmonic components, fundametal compoment and DC component；
Wherein DC component and even-order harmonic are not involved in electrical energy measurement, and the analysis of causes is as follows：
Wherein voltage is sine wave：U (t)=Usin (ω t)
Active power：
Since direct current and even-order harmonic are zero to power measurement, so：
Therefore current transformer is needed fundamental current i.e.It can be complete errorless
Be converted into it is secondary can accurate measurement；
Because DC component can not be reflected into secondary current by current transformer, the time domain expression of secondary current is public
Formula is：
Thus the ratio difference and angular difference value of fundamental current are derived：
f50Hz=(K × I1'-I1)/I1× 100.0 (%) (6)
K is the electric current ratio of the primary current and secondary current of current transformer in formula.
The present invention has the following technical effects：
1, the present invention is flowed up using pressure regulator and current lifting device, half-wave current is exported using diode rectification, using standard
Half-wave current of resistance sampling and mutual inductor secondary current, use simple and reliable amplifying circuit and high-resolution A/
D sample conversion modules calculate each harmonic content size of primary current and secondary current by FFT fast Fourier algorithms
And phase relation, and then obtain the ratio error and phase error of fundamental wave.Since circuit design is reasonable, algorithm is accurate, dress
The accuracy and stability set are protected.By using 14 A/D sample conversion module measuring signals, the resolution ratio of A/D is
1/8192, therefore the anti-DC component current transformer of calibration can reach 0.1% accuracy.Anti- DC component current transformer
It is required that being 3%, meets the needs of test accuracy.
2, pressure regulator, current lifting device, current-limiting resistance and the first rectifier diode D1 and the second rectification two that the present invention uses
Pole pipe D2 realizes that output half-wave current, output waveform are consistent with real work electric current.Output capacity is big, current range covering
Width meets the testing requirement of all miniature anti-DC component current transformers.
3, the impedance matching function that the present invention uses can effectively reduce the asymmetric situation of sine wave half-wave up and down, survey
Try influence of the DC current to current lifting device and pressure regulator.
4, the present invention is generated using DSP digital signal processor timer internal tranmitting data register signal method and is believed sine wave
The principle of number complete cycle wave sampling, thus the frequency of measured signal can be 50Hz, 60Hz or other frequencies.First controllable gain is put
Using 0.02 grade of line around precision resistance in big device and the second controllable gain amplifier, circuit full dose limit meets 0.05 grade of amplification
Accuracy and the linearity.More automation functions may be implemented using human-computer interaction module and data processing module.
5, the present invention need not be by the way of standard current transformer and error of measurement checking circuit, it is only necessary to which input is tested anti-
The basic parameter of DC component current transformer has good adaptability.Pass through number after measuring A/D discrete data floating-points
It is calculated according to processing module, other than it can analyze fundamental wave and direct current signal, the case where each harmonic can also be analyzed.
Description of the drawings
Attached drawing 1 is the circuit connection diagram of the embodiment of the present invention 1.
Attached drawing 2 is the method flow diagram of the embodiment of the present invention 2.
Attached drawing 3 is the detection wiring diagram of tracing to the source of the embodiment of the present invention 4.
Coding in attached drawing is respectively：R1 is the first half-wave current sampling resistor, and R2 is the second half-wave current sampling resistor,
R3 is current-limiting resistance, and D1 is the first rectifier diode, and D2 is the second rectifier diode, and CH1 is external the first wiring of interface of tracing to the source
Column, CH2 are external the second binding post of interface of tracing to the source, and CT is anti-DC component current transformer.
Specific implementation mode
The present invention is not limited by following embodiments, can be determined according to the technique and scheme of the present invention with actual conditions specific
Embodiment.
With reference to embodiment and attached drawing, the invention will be further described：
Embodiment 1：As shown in Fig. 1, based on the anti-DC component current transformer error tester packet under halfwave rectifier
Shell, anti-DC component current transformer test circuit and data processing unit are included, the anti-DC component current transformer is surveyed
Examination circuit and data processing unit are arranged in shell, and anti-DC component current transformer test circuit includes pressure regulator, rises
Flow device, the first rectifier diode D1, the second rectifier diode D2, current-limiting resistance R3, the first half-wave current sampling resistor R1, second
Half-wave current sampling resistor R2, the external AC power of input terminal of the pressure regulator, the output end of pressure regulator respectively with current lifting device
First binding post and the second binding post connection, current lifting device third binding post respectively with the anode of the first rectifier diode D1 in parallel
It is connected with the cathode of the second rectifier diode D2, the 4th binding post of current lifting device is connect with current-limiting resistance R3, current-limiting resistance R3 and
External build-out resistor, first the first binding posts of half-wave current sampling resistor R1 and are connected between one rectifier diode D1 cathode
Two rectifier diode D2 anodes connect, and data processing unit includes A/D sample conversions module, data processing module and ARM modules,
A/D sample conversion modules are connect with data processing module, and ARM modules obtain the basic test information for being detected current transformer, ARM
The tested current transformer basic test information of input is sent to data processing module by module.
In actual use, the primary coil for being detected anti-DC component Current Transmit is connected on the sampling of the first half-wave current
Between resistance R1 and current-limiting resistance R3, the secondary coil and the second half-wave current that are detected anti-DC component Current Transmit sample
Resistance R2 is in parallel, and the half-wave current all the way come out from current lifting device is by being detected anti-DC component Current Transmit and the first half-wave
Current sampling resistor R1, another way half-wave current is converged again by external matching impedance and preceding half-wave current all the way passes through limit
Leakage resistance R3, is back to current lifting device.The purposes of current-limiting resistance：The waveform that half-wave current can be improved, makes half-wave current waveform and resists
Waveform in DC component practical application is consistent.If not current-limiting resistance R3, since test loop impedance is very low, cause
Current lifting device output voltage only needs the size for overcoming the conducting voltage of rectifier diode that can just reach test electric current quickly later,
But since the pulsewidth of rectifier diode conducting is relatively narrow, output half-wave current is similar as pulse current, rather than half-wave is electric
Stream.Current-limiting resistance R3 can undertake the voltage of more ratio, and rectifier diode conducting voltage accounts for compared with current lifting device output voltage
It is smaller, it is consistent with the half-wave current of real work.
Above-mentioned data processing module is designed by the processor of DSP core, is the key that device observing and controlling component；Data processing mould
Block is internally provided with timer, continuously sends a clock signal and gives A/D sample conversion modules, A/D sample conversion modules
As enabling signal, the frequency of clock signal is 2.56kHz, is 512 times of power frequency component.Operating personnel rotate on case panel
Pressure regulator knob, 0V~250V voltages can be exported, which can export 0A~100A through the current lifting device for decompression
Alternating current.Operating personnel export corresponding alternating current amplitude as neededImax is tested Current Mutual Inductance
The maximum operating currenbt of device.Generally tested current transformer Imax has 60A, 100A etc..
The S3C44B0 embedded system structures realization that Samsung ARM7TDMI kernels can be used in above-mentioned ARM modules is man-machine right
Words, S3C44B0 are 16/32 bit processors (66MHz) using 160LQFP encapsulation.Provide abundant build-in components and comprehensively
, general On-Chip peripheral, greatly reduce the component configuration in addition to processor in circuit system.To minimize this hair
Bright cost.Basic parameter and operational order are sent to data processing mould by ARM modules and data processing module data interaction
Data are returned to ARM modules by block after data processing module processing.
The measurement and calculating of DSP digital signal processor realization analog quantity can be used in data processing module, to realize half-wave
Rectified current transformer error measures.DSP digital signal processor refers to the current mutual-inductor parameter that ARM modules are sent is received
It enables, DSP digital signal processor carries out complete cycle wave sampling 512 using Timer Controlling A/D sample conversions module to power frequency component
Point, A/D sample conversion modules measure the voltage on the first half-wave current sampling resistor and the second half-wave current sampling resistor, make A/
For the sampled voltage of D sample conversion modules always in linearly interval, it is accurate to ensure to measure.Current Mutual Inductance is obtained by calculation formula
The ratio difference of device fundamental wave and angular difference value.
MAX125BCNI converters can be used in A/D sample conversion modules.The A/D sample conversion modules are a kind of high speed, more
Channel, 12 modulus conversion chips, modulus conversion chip inside band are gradually forcing for 3 microseconds there are one 14, conversion time
Plesiotype modulus circuit, 4 × 14 RAM can be with the ternary output device of digital signal processor bus interface；There are 4 in piece
(T/H) is adopted/protects, the output each adopted/protected corresponds to one 2 and 1 simulation input is selected (to share 8 analog input channels, 4 one group, divide
For two groups of A and B), output selects 1 switch to A/D sample conversion modules through 4.
The above-mentioned anti-DC component current transformer error tester based under halfwave rectifier can be made according to actual needs
Further optimization and/or improvements：
As shown in Fig. 1, it is additionally provided on hull outside face and external traces to the source interface the first binding post CH1 and external trace to the source connects
Mouthful second binding post CH2, first half-wave current sampling resistor R1 second and third binding post are connected to external the first wiring of interface of tracing to the source
On column CH1, two binding posts of the second half-wave current sampling resistor R2 are both connected to external the second binding post of interface CH2 that traces to the source
On, external interface the first binding post CH1 and external the second binding post of interface CH2 that traces to the source that traces to the source connects with A/D sample conversion modules
It connects.Here external interface the first binding post CH1 and external the second binding post of interface CH2 that traces to the source that traces to the source being arranged on hull outside face
Higher level's correcting mechanism is used to carrying out error based on the anti-DC component current transformer error tester under halfwave rectifier
Calibration, staff is as needed, and first half-wave current sampling resistor R1 second and third binding post is connected to external trace to the source manually
On the first binding post of interface CH1, two binding posts of the second half-wave current sampling resistor R2 are connected to external trace to the source and connect manually
On the second binding post CH2 of mouth.
As shown in Fig. 1, it is connected with first between external interface the first binding post CH1 and A/D sample conversion module of tracing to the source
Controllable gain amplifier is connected with second between external interface the second binding post CH2 and A/D sample conversion module of tracing to the source and controllable increases
Beneficial amplifier.
As needed, further include communication module and host computer, host computer is connect with ARM modules by communication module.It is upper
After machine is connect with ARM modules, host computer can realize the measurement data of the automatic tested current transformer for obtaining calibration, can also
Carry out data management.
As shown in Fig. 1, further include keyboard and display, keyboard and display are connect with ARM modules.Here display
Device can be liquid crystal display, for showing test data, and show it is apparent, convenient for staff record check data.
As shown in Fig. 1, further include data storage, data storage is connect with ARM modules.
As needed, it is additionally provided with radiation panel, radiation panel is fixedly mounted on and the first half-wave current sampling resistor R1
In the second corresponding housing bottom surface in the positions half-wave current sampling resistor R2.Radiation panel plays cooling effect, ensures the
The Wen Sheng of one half-wave current sampling resistor R1 and the second half-wave current sampling resistor R2 are less than 30 degree, have ensured the accurate of sampling
Degree.
Embodiment 2：As shown in Fig. 2, a kind of above-mentioned anti-DC component current transformer error based under halfwave rectifier is surveyed
The test method for trying instrument, includes the following steps：
Step 1, primary current, secondary current and the secondary load of anti-DC component current transformer are set；
Step 2, a half-wave current I of current transformer is acquired by the first half-wave current sampling resistor R11, pass through
Two half-wave current sampling resistor R2 measure secondary current I2, measuring signal by 1 to 64 times of the first controllable gain amplifier and
Second controllable gain amplifier amplification after be synchronized to A/D sample conversion module ports so that measuring signal 1.2V to 2.5V it
Between, crest voltage is less than 4V, in the linearly interval of A/D sample conversion modules；
Step 3, it controls A/D sample conversions module using data processing module and 512 point sampling of complete cycle wave is carried out to signal, obtain
To discrete digital signal, i.e. the first half-wave current I1Pass through the mathematics model analysis of current transformer：First half-wave current I1 is
One non-sinusoid, the first half-wave current I1Half-wave voltage is generated by the first half-wave current sampling resistor R1, is sampled using A/D
Conversion module measurement obtains discrete voltage, and DC component, fundametal compoment and each even is calculated by Fourier FFT
The current value of harmonic component, full-wave electric current virtual value IqFor the first half-wave current virtual value I1'sTimes, the first half-wave current I1
Time-domain expression after electric current Fourier transformation is：
Wherein the 45% of DC current accounting full-wave electric current, 50%, the 100Hz electric currents of fundamental current accounting full-wave electric current are about
The 23% of accounting fundamental current, also other even-order harmonic electric currents are also proportional；The virtual value of half-wave current is equal to each of it
The square root of the virtual value quadratic sum of order harmonic components, fundametal compoment and DC component；
Wherein DC component and even-order harmonic are not involved in electrical energy measurement, and the analysis of causes is as follows：
Wherein voltage is sine wave：U (t)=Usin (ω t)
Active power：
Since direct current and even-order harmonic are zero to power measurement, so：
Therefore current transformer is needed fundamental current i.e.It can be complete errorless
Be converted into it is secondary can accurate measurement；
Because DC component can not be reflected into secondary current by current transformer, the time domain expression of secondary current is public
Formula is：
Thus the ratio difference and angular difference value of fundamental current are derived：
f50Hz=(K × I1'-I1)/I1× 100.0 (%) (6)
K is the electric current ratio of the primary current and secondary current of current transformer in formula.
In above-mentioned steps 1, it can be instructed by host computer or the primary current, secondary of mutual inductor is arranged in the method for manual entry
Electric current and secondary load；
As long as by above-mentioned steps 3 as it can be seen that a half-wave current is accurately measured, secondary current accurately measures, using fast
Fundamental current range value and fundamental current phase angle meter are calculated and be can be obtained using formula (6) and formula (7) by fast Fourier transformation
Ratio difference of the current transformer under half-wave current and angular difference value.
Embodiment 3：As shown in table 1, the measurement obtained using the test method of standard current transformer and DC power supply
For data compared with the present invention, measurement data deviation is less than the 1/3 of current transformer half-wave error limit.Two kinds of halfwave rectifier
Error measure scheme is table 1 to the measurement data of same current transformer.
It can see by table 1：Two different test devices test same current transformer, and obtained result is less than
The 1/3 of the 3 grades or 6 grades error limits that standard requires, inventive can be verified.
Compared with halfwave rectifier (direct current and even-order harmonic) detection method, according to a large amount of test data analyzer, half
Than poor Δ f substantially between -1.0% to 2.5%, angular difference Δ δ's qualified current transformer fundamental wave exists substantially under wave rectification state
250 points to 450/.Median -1.8% and 350 points of power calculations for making electric energy meter are taken, the electric energy of electric energy meter at this time is studied
Measurement error is how many.
It is theoretical：
It is practical：
The electric energy metering error brought is
Because power factor command when national regulations halfwave rectifier error test is equal to 1.0, i.e.,Degree, therefore
It arrives：
ε=(1- (1+ Δs f)) × cos (Δ δ) × 100.0 (12)
Δ f=-1.8%, angular difference Δ δ=350' are brought into formula 12 and obtain ε=- 2.31%
Measurement result and the data kissing directly obtained using test method using GB/T 17215.321-2008 standards
It closes.The ratio difference and angular difference value for showing mutual inductor simultaneously all have an impact electric energy meter metering, wherein the influence generated than difference
It is larger.
Embodiment 4：As shown in attached drawing 3, table 2, using based on the anti-DC component current transformer error under halfwave rectifier
Tester carries out sub-unit test method：
Primary current is sampled using RNG power-type four-wire system standard sample resistors R1, with resistance-strain principle.
Using the noninductive structure design of plane, precision is up to 0.01%, temperature coefficient 5ppm.Use 4 milliohms, rated current 80A,
The RNG resistance of 0.05 grade of accuracy.We are detected using eight and half tables of Agilent 3458A and the DC power supply of 0.01% stability
The accuracy of the resistance and stability, measured data reach 0.03%.
Secondary current is sampled using RX710 type accurate type wire wound measuring resistances R2, and resistance value has 5 ohm, 10 ohm and 20
Ohm third gear is optional, and accuracy is 0.02 grade.It is nominal that the data tested using detection means identical with RNG reach resistance
Index.
The accuracy of tested current transformer test circuit and software algorithm can also trace to the source, using JJG169-2010《Mutually
Sensor tester vertification regulation》It is detected, ARM module input parameters so that the coefficient ratio K in two channels is 1, by standard
Signal(amplitude range is 0.085V~0.141V, and correspondence passes throughHalf-wave current in 4 milliohm sample resistances
The fundamental voltage virtual value of generation) it is input between CH1 terminals, it has been superimposed another standard signal of difference signalTo CH2
Between terminal.Different ratio differences and angular difference value are exported by the device, and instrument is by the ratio between showing two standard signals
Error and phase error.In instrument display data than poor deviation must not exceed Δ X=± (| X × 1% |+| Y × 1% |+
0.1) %, angular difference deviation be no more than Δ y=± (| X × 1% |+| Y × 1% |+5) '.Detection wiring of tracing to the source is Fig. 3.Testing number
According to being shown in Table 2.
The above technical characteristic constitutes the embodiment of the present invention, can basis with stronger adaptability and implementation result
Actual needs increases and decreases non-essential technical characteristic, to meet the needs of different situations.
1 mutual inductor sample error measurement result deck watch of table
2 mutual-inductor tester calibrating installation verification test circuit of table and algorithm data table
Claims (10)
1. a kind of anti-DC component current transformer error tester, it is characterised in that mutual including shell, anti-DC component electric current
Sensor test circuit and data processing unit, the anti-DC component current transformer test circuit and data processing unit are all provided with
It sets in shell, anti-DC component current transformer test circuit includes pressure regulator, current lifting device, the first rectifier diode, second
Rectifier diode, current-limiting resistance, the first half-wave current sampling resistor, the second half-wave current sampling resistor, the pressure regulator it is defeated
Enter to hold external AC power, the output end of pressure regulator to be connect respectively with the first binding post of current lifting device and the second binding post, current lifting device
Third binding post is connect with the cathode of the anode of the first rectifier diode in parallel and the second rectifier diode respectively, current lifting device the
Four binding posts are connect with current-limiting resistance, and external build-out resistor is connected between current-limiting resistance and the first rectifier diode cathode, the
One the first binding post of half-wave current sampling resistor is connect with the second rectifier diode anode, and data processing unit includes A/D samplings
Conversion module, data processing module and ARM modules, A/D sample conversion modules are connect with data processing module, and ARM modules obtain
The tested current transformer basic test information of input is sent to by the basic test information of tested current transformer, ARM modules
Data processing module.
2. anti-DC component current transformer error tester according to claim 1, it is characterised in that hull outside face
On be additionally provided with external trace to the source the first binding post of interface and external the second binding post of interface of tracing to the source, the first half-wave current sampling resistor
Second and third binding post be connected to it is external trace to the source on the first binding post of interface, two binding posts of the second half-wave current sampling resistor
Be both connected to it is external trace to the source on the second binding post of interface, external trace to the source the first binding post of interface and external the second wiring of interface of tracing to the source
Column is connect with A/D sample conversion modules.
3. anti-DC component current transformer error tester according to claim 2, it is characterised in that external trace to the source connects
It is connected with the first controllable gain amplifier between the first binding post of mouth and A/D sample conversion modules, external interface second of tracing to the source connects
It is connected with the second controllable gain amplifier between terminal and A/D sample conversion modules.
4. anti-DC component current transformer error tester according to claim 1 or 2 or 3, it is characterised in that also wrap
Communication module and host computer are included, host computer is connect with ARM modules by communication module.
5. anti-DC component current transformer error tester according to claim 1 or 2 or 3, it is characterised in that also wrap
Keyboard and display are included, keyboard and display are connect with ARM modules.
6. anti-DC component current transformer error tester according to claim 4, it is characterised in that further include keyboard
And display, keyboard and display are connect with ARM modules.
7. anti-DC component current transformer error tester according to claim 1 or 2 or 3, it is characterised in that also wrap
Data storage is included, data storage is connect with ARM modules.
8. anti-DC component current transformer error tester according to claim 4, it is characterised in that further include data
Memory, data storage are connect with ARM modules.
9. the anti-DC component current transformer error tester according to claims 1 or 2 or 3 or 6 or 8, feature exist
In being additionally provided with radiation panel, radiation panel is fixedly mounted on and the first half-wave current sampling resistor and the sampling of the second half-wave current
On the metal base plate of the corresponding housing bottom of resistance position.
10. a kind of test side of anti-DC component current transformer error tester as claimed in any one of claims 1-9 wherein
Method, it is characterised in that include the following steps：
Step 1, primary current, secondary current and the secondary load of anti-DC component current transformer are set；
Step 2, the half-wave current that current transformer is acquired by the first half-wave current sampling resistor R1, passes through the second half-wave
Current sampling resistor R2 measures secondary current, and measuring signal is controllable by 1 to 64 times of the first controllable gain amplifier and second
It is synchronized to A/D sample conversion module ports after gain amplifier amplification so that measuring signal is between 1.2V~2.5V, peak value electricity
Pressure is less than 4V, in the linearly interval of A/D sample conversion modules；
Step 3, control A/D sample conversions module using data processing module and 512 point sampling of complete cycle wave carried out to signal, obtain from
Dissipate digital signal, i.e., the mathematics model analysis that the first half-wave current passes through current transformer：First half-wave current be one it is non-just
String amount, the first half-wave current generate half-wave voltage by the first half-wave current sampling resistor, are measured using A/D sample conversion modules
Discrete voltage is obtained, the electricity of DC component, fundametal compoment and each even-order harmonic component is calculated by Fourier FFT
Flow valuve, full-wave electric current virtual value are the first half-wave current virtual valueTimes, the first half-wave current through electric current Fourier transformation it
Time-domain expression afterwards is：
Wherein the 45% of DC current accounting full-wave electric current, 50%, the 100Hz electric currents about accounting of fundamental current accounting full-wave electric current
The 23% of fundamental current, also other even-order harmonic electric currents are also proportional；The virtual value of half-wave current be equal to it each time it is humorous
The square root of the virtual value quadratic sum of wave component, fundametal compoment and DC component；
Wherein DC component and even-order harmonic are not involved in electrical energy measurement, and the analysis of causes is as follows：
Wherein voltage is sine wave：U (t)=Usin (ω t)
Active power：
Since direct current and even-order harmonic are zero to power measurement, so：
Therefore current transformer is needed fundamental current i.e.It completely errorless can be converted into
It is secondary can accurate measurement；
Because DC component can not be reflected into secondary current, the time domain expression formula of secondary current by current transformer
For：
Thus the ratio difference and angular difference value of fundamental current are derived：
f50Hz=(K × I '1-I1)/I1× 100.0 (%) (6)
K is the electric current ratio of the primary current and secondary current of current transformer in formula.
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| CN109085529A (en) * | 2018-10-16 | 2018-12-25 | 国家电网有限公司 | A kind of composition error detection platform emulating pulse conversion station harmonic signal |
| CN109375133A (en) * | 2018-09-17 | 2019-02-22 | 国网江西省电力有限公司电力科学研究院 | A kind of resistance to DC performance detection device of current sensor and method |
| CN109581265A (en) * | 2018-10-30 | 2019-04-05 | 国网江西省电力有限公司电力科学研究院 | A kind of anti-DC performance detection method of current transformer based on power error |
| CN110133563A (en) * | 2019-05-13 | 2019-08-16 | 国网江西省电力有限公司电力科学研究院 | A kind of anti-DC performance detection method and device of current sensor |
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| CN112858989A (en) * | 2021-03-30 | 2021-05-28 | 云南电网有限责任公司电力科学研究院 | Current transformer calibration system |
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| CN109375133A (en) * | 2018-09-17 | 2019-02-22 | 国网江西省电力有限公司电力科学研究院 | A kind of resistance to DC performance detection device of current sensor and method |
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| CN110133563A (en) * | 2019-05-13 | 2019-08-16 | 国网江西省电力有限公司电力科学研究院 | A kind of anti-DC performance detection method and device of current sensor |
| CN111751604A (en) * | 2020-07-01 | 2020-10-09 | 国网江苏省电力有限公司营销服务中心 | Steady-state test method and system for transient voltage overshoot value of direct-current voltage divider |
| CN111751604B (en) * | 2020-07-01 | 2022-12-13 | 国网江苏省电力有限公司营销服务中心 | Steady-state test method and system for transient voltage overshoot value of direct-current voltage divider |
| CN112858989A (en) * | 2021-03-30 | 2021-05-28 | 云南电网有限责任公司电力科学研究院 | Current transformer calibration system |
| CN114047702A (en) * | 2021-11-24 | 2022-02-15 | 中国核动力研究设计院 | Self-adaptive extraction method and system for effective value of rotating current of control rod drive wire |
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