CN108414960A - A kind of multichannel directly measures formula mutual-inductor tester and method of calibration - Google Patents
A kind of multichannel directly measures formula mutual-inductor tester and method of calibration Download PDFInfo
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- CN108414960A CN108414960A CN201810330972.5A CN201810330972A CN108414960A CN 108414960 A CN108414960 A CN 108414960A CN 201810330972 A CN201810330972 A CN 201810330972A CN 108414960 A CN108414960 A CN 108414960A
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- G—PHYSICS
- G01—MEASURING; TESTING
- 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 invention discloses a kind of multichannels directly to measure formula mutual-inductor tester and method of calibration, and the up to 8 road test item error checkings of three-phase voltage+residual voltage and three-phase current+zero-sequence current may be implemented；Normal voltage or current transformer only can need to use software conversion to can be obtained result with subject voltage or current transformer difference no-load voltage ratio；Voltage or Current Transformer Secondary output voltage or electric current are since using precision transformer isolation sampling, in the case where flashover occurs for extra-high voltage, EHV Potential Transformer error test, tester of the present invention is hardly damaged；Measurement circuit is simple, only need to be by the instrument of standard mutual inductor and the secondary output voltage of tested mutual inductor or current signal the access present invention without error of measurement test loop.
Description
Technical field
The present invention relates to Electric Energy Metering Technology field, especially a kind of multichannel directly measures formula mutual-inductor tester and school
Proved recipe method.
Background technology
At present to the method Main Basiss JJG313-2010 of traditional voltage (electric current) transformer error calibrating《It measures and uses
Current transformer》And JJG314-2010《Measurement voltage transformer》、JJG1021-2007《Electric power mutual-inductor》Three calibrating rule
Journey.Calibration method need using normal voltage (electric current) mutual inductor, mutual-inductor tester, voltage (electric current) mutual inductor load box with
And boosting (up-flow) device.The core of test method is that normal voltage (electric current) mutual inductor connects with subject voltage (electric current) mutual inductor
At error of measurement circuit, standard loop is measured together with difference circuit using mutual-inductor tester, the final tested electricity of display of tester
Press the ratio difference and differential seat angle of (electric current) mutual inductor.The calibration method is the authoritative scheme that measurement transformer is traced to the source.Highest can
To be traceable to National primary standard.
The current transformer error of the three-phase combination transformer of threephase current transformer composition measures, when experiment, according to surveying
Amount point is respectively mutually pressed comparison method error of measurement circuit, is detected respectively by three-phase mutual-inductor tester to tested current transformer Injection Current
Go out error amount.When examining and determine Y connection three-phase combination transformers, it is combined that error measure circuit and the V of current transformer couple three
The measurement circuit of mutual inductor is identical.Y couples measurement three-phase combination voltage mutual inductor, and tested voltage is given according to defined measurement point
Mutual inductor applies voltage, each mutually to press comparison method error of measurement circuit, and error amount is detected respectively by three-phase mutual-inductor tester.Y couples
Remaining winding/zero sequence voltage measuring transformer is given tested voltage transformer to apply voltage, is respectively mutually pressed according to defined measurement point
Comparison method error of measurement circuit, error amount is detected by mutual-inductor tester.Combination transformer (three-phase combined
Instrument transformer) by threephase potential transformer and three single-phase (or two single-phase), current transformer combination is simultaneously
Formed one for three-phase electrical power system metering, measuring mutual inductor.
Electronic type voltage transformer (sensor)：It is that a kind of novel " three-phase voltage+residual voltage " measures one-piece type mutual inductance
Device (sensor).Mutual inductor is manufactured using traditional electromagnetic induction principle, and output is generally 100V, 57.7V or 100/3V voltage；
Sensor uses capacitance partial pressure technology, can be small analog quantity electricity with precise acquisition three-phase voltage and residual voltage, secondary output
Pressure.
Electronic current mutual inductor (sensor)：It is that " three-phase current+zero-sequence current " measures one-piece type sensor, it is secondary
Output has traditional secondary current mode and secondary small analog voltage two ways.Electronic type voltage transformer (sensor) and electricity
Type current transformer (sensor) is mainly used in one or two fusion devices of 10kV distributions, and letter is provided to protection equipment is measured
Number.
The single plane method of national verification regulation may be used by mutually examining and determine in combination transformer.But electronic type voltage, electric current are mutual
Sensor (sensor) then cannot achieve verification.Even there is existing three-phase mutual-inductor tester that can not also be passed to electronic type at present
Sensor verifies.The class of accuracy of combination transformer and voltage current transformer (sensor) is generally：0.5 grade, 0.2 grade or electric current it is mutual
Sensor (sensor) is 0.5S grades, 0.2S grades.
Due to the presence of the mutual inductor or sensor of three of the above mode, and class of accuracy is no more than 0.2 (0.2S) grade,
It can be achieved to measure using the present invention.Using the direct method of measurement, by normal voltage (electric current) mutual inductor and tested voltage (electricity
Stream) the synchronous A/D of secondary output voltage (electric current) of mutual inductor/sensor measures, and measurement obtains discrete shape data and is converted into floating
Points obtain standard signal and the fundamental voltage amplitude and phase difference of measured signal, into one using floating type Fast Fourier Transform (FFT)
Step can calculate the ratio difference and angular difference value of tested mutual inductor (sensor).
Invention content
Technical problem to be solved by the present invention lies in provide a kind of multichannel and directly measure formula mutual-inductor tester and school
Proved recipe method can solve the single-phase experiment of existing mutual-inductor tester, need to use difference loop test and can only be examined and determine with no-load voltage ratio
The problem of.
In order to solve the above technical problems, a kind of multichannel of present invention offer directly measures formula mutual-inductor tester, including：
DSP circuit, ARM circuits, liquid crystal, keyboard, storage, RS232, power supply, 8 tunnels sampling accurate voltage mutual inductor VT1~VT8,8 tunnels take
Sample precision current transformer TA1~TA8,8 road sample resistance Rc, 8 road voltage signal amplitude limiter circuits, No. 4 voltage transformers/sensing
Device signal selector relay group J1~J16, No. 4 current transformers/sensor signal selective relay group J17~J24,16 roads electricity
Programmable amplifying circuit V1~V8 and A1~A8,28 channel parallels is pressed to sample 16 A/D circuits V_A/D and A_A/D, 4 groups of ranges
Switch relay and switch I/O expanded circuit V1_I/O, V2_I/O, A1_I/O and A2_I/O, all mounted on 4U standard
In Aluminum Alloy Chassis；DSP circuit respectively with ARM circuits, 16 tunnel voltage-programmed amplifying circuit V1~V8 and A1~A8,28 channels
Parallel sampling 16 A/D circuits V_A/D and A_A/D, 4 groups of range switching relay switching I/O expanded circuits V1_I/O, V2_I/
O, A1_I/O is connected with A2_I/O；ARM circuits are connected with liquid crystal, storage, keyboard and RS232 respectively；8 tunnel voltage-programmeds are put
Big circuit V1~V8 respectively with 8 road voltage signal amplitude limiter circuits, No. 4 voltage transformers/sensor signal selective relay group J1
~J16,8 tunnels sampling accurate voltage mutual inductor VT1~VT8 are sequentially connected；8 tunnel voltage-programmed amplifying circuit A1~A8 are respectively with 4
Road current transformer/sensor signal selective relay group J17~J24,8 road sample resistances, 8 tunnels sample precision current transformer
TA1~TA8 is sequentially connected.
Preferably, voltage-programmed amplifying circuit specifically includes：First operational amplifier, second operational amplifier, third fortune
Calculate amplifier, four-operational amplifier, the first programme control precision divider resistance chip N1, the second programme control precision divider resistance chip N2
With third programme control precision divider resistance chip N3；The output end of first operational amplifier connects the first programme control precision divider resistance core
2 pins of piece N1, the inverting input of the first operational amplifier are connected to the output end of the first operational amplifier and first program-controlled
Between 2 pins of accurate divider resistance chip N1, the normal phase input end of the first operational amplifier connects KD；First programme control precision point
The normal phase input end of the 6 pins connection second operational amplifier of piezoresistance chip N1, the first programme control precision divider resistance chip N1
8 pins connection second operational amplifier inverting input, the output end of second operational amplifier connects the second programme control precision
4 pins of 2 pins of divider resistance chip N2, the first programme control precision divider resistance chip N1 are connected to second operational amplifier
Between output end and 2 pins of the second programme control precision divider resistance chip N2；6 pipes of second programme control precision divider resistance chip N2
Foot connects the normal phase input end of third operational amplifier, the 8 pins connection third fortune of the second programme control precision divider resistance chip N2
The inverting input of amplifier is calculated, the output end of third operational amplifier connects the 2 of third programme control precision divider resistance chip N3
Pin, 4 pins of the second programme control precision divider resistance chip N2 be connected to third operational amplifier output end and third it is program-controlled
Between 2 pins of accurate divider resistance chip N3；6 pins of third programme control precision divider resistance chip N3 connect the 4th operation and put
The reverse phase of the normal phase input end of big device, the 8 pins connection four-operational amplifier of third programme control precision divider resistance chip N3 is defeated
Enter end, the output end of four-operational amplifier connects KDFA, and 4 pins of third programme control precision divider resistance chip N3 are connected to the
Between the output end and KDFA of four-operational amplifier.
Preferably, 28 channel parallels, 16 A/D circuits of sampling are specially：A/D circuit digital part of interface：Wherein D0~
The bus of D15 and DSP connects, and the timer output pin of/COVST and DSP connect, and for starting A/D samplings ,/AD-END connects
The interrupting input mouth of DSP makes DSP enter interrupt handling routine after being sampled for A/D by middle fracture, and DSP enters interruption
A/D measured values are read out after processing routine ,/CS-7606 is chip selection signal, and/RES_7606 is reset signal, and/RD is total
Line reads signal, and+5VA2 is bus driver power supply；A/D breadboardin part of interface：CH1~CH8 is analog measurement input,
AVCC is that simulation power supply interface, AGND, V1GND~V8GND are ground interfaces, defeated with two APL117.5V three-terminal voltage-stabilizing power supplys
Go out power supplies of two independent 5V as A/D chips, wherein+5VA is simulation power supply all the way, another way+5VA2 is digital power system,
AD780 fiducial chips are used to export 2.5V to A/D chips as reference voltage REF；Simulation ground AGND and digitally GND is in A/D cores
Piece bottom short circuit.
Correspondingly, a kind of multichannel directly measures the method for calibration of formula mutual-inductor tester, include the following steps：
(1) tester measures the secondary output voltage or electric current of voltage transformer or current transformer, each channel respectively
Voltage synchronous obtains 512 A/D of a cycle and measures shape data；
(2) tester calculates the amplitude size and phase difference of each channel voltage by cured software in DSP circuit,
And then be calculated standard potential transformer or current transformer and tested voltage transformer or current transformer ratio difference and
Angular difference value.
Preferably, in step (2), tester obtains standard mutual inductor and tested mutual inductor or sensing by A/D measurements
The secondary singal of device, each period uniformly obtain 512 discrete signal values, this two groups of 512 measurement data are converted into floating-point
Number, and substitute into fast fourier transform algorithm FFT and two groups of letters of standard mutual inductor and tested mutual inductor (sensor) are calculated
Number expression formula；Signal amplitude value and initial phase containing fundametal compoment and each harmonic component in expression formula；
By taking current transformer is tested calibration as an example：Two groups of secondary currents of standard current transformer and tested current transformer
The two groups of time-domain expressions that obtain after signal is fourier transformed are：
Wherein：I (t) is standard current transformer secondary current signal, i'(t) it is that standard current transformer secondary current is believed
Number, InAnd I'nFor each harmonic virtual value size,WithFor the starting phase angle of each harmonic；
Tester is by software by the secondary base of the secondary fundamental signal and tested current transformer of standard current transformer
Wave signal obtains the ratio difference of tested current transformer by formula (3)；The phase of tested current transformer is obtained by formula (4)
Angular difference；
Wherein：K1To be tested the electric current ratio of current transformer, K0For the electric current ratio of standard current transformer；I0For standard electric
Current transformer fundamental wave virtual value, I'0To be tested current transformer fundamental wave virtual value；For standard current transformer fundamental wave initial phase
Position,To be tested current transformer fundamental wave initial phase；f50HzIt is to be tested current transformer fundamental wave than difference, δ50HzFor tested electricity
Current transformer fundamental wave angular difference value.
It is measured as current sensor or is measured as voltage transformer (sensor) to be also to use the identical meter of formula (1~4)
Calculation method, only definition have difference.
Beneficial effects of the present invention are：Three-phase voltage+residual voltage and three-phase current+zero-sequence current may be implemented up to
8 road test item error checkings；Normal voltage (electric current) mutual inductor can only be needed with subject voltage (electric current) mutual inductor difference no-load voltage ratio
Result can be obtained using software conversion；The secondary output voltage of voltage (electric current) mutual inductor (electric current) is due to using precision transformer
Isolation sampling, the tester of the present invention not rapid wear in the case where flashover occurs for extra-high voltage, EHV Potential Transformer error test
It is bad；Measurement circuit is simple, only need to be by standard mutual inductor and the secondary output voltage of tested mutual inductor without error of measurement test loop
The instrument of (electric current) signal access present invention.
Description of the drawings
Fig. 1 is the tester structural schematic diagram of the present invention.
Fig. 2 is that the mutual-inductor tester of the present invention verifies threephase potential transformer wiring diagram.
Fig. 3 is that the mutual-inductor tester of the present invention verifies three-phase voltage sensor wire figure.
Fig. 4 is that the mutual-inductor tester of the present invention verifies threephase current transformer wiring diagram.
Fig. 5 is that the mutual-inductor tester of the present invention verifies three-phase current sensor wiring diagram.
Fig. 6 is that the mutual-inductor tester of the present invention verifies three-phase zero sequence current mutual inductor wiring diagram.
Fig. 7 is that the mutual-inductor tester of the present invention verifies three-phase zero sequence current sensor wiring diagram.
Fig. 8 is that the mutual-inductor tester of the present invention verifies programmable amplifying circuit principle schematic.
Fig. 9 is the A/D circuit theory schematic diagrams of the present invention.
Specific implementation mode
As shown in Figure 1, a kind of multichannel directly measures formula mutual-inductor tester, including：DSP circuit, ARM circuits, liquid crystal,
Keyboard, storage, RS232, power supply, 8 tunnels sampling accurate voltage mutual inductor VT1~VT8,8 tunnels sampling precision current transformer TA1~
TA8,8 road sample resistance Rc, 8 road voltage signal amplitude limiter circuits, No. 4 voltage transformers/sensor signal selective relay group J1
~J16, No. 4 current transformers/sensor signal selective relay group J17~J24,16 tunnel voltage-programmed amplifying circuit V1~V8
16 A/D circuits V_A/D and A_A/D, 4 groups of range switching relay switching I/O extensions are sampled with A1~A8,28 channel parallels
Circuit V1_I/O, V2_I/O, A1_I/O and A2_I/O, all in the Aluminum Alloy Chassis of a 4U standard；DSP circuit point
16 A/D circuits V_ are not sampled with ARM circuits, 16 tunnel voltage-programmed amplifying circuit V1~V8 and A1~A8,28 channel parallels
A/D is connected with A_A/D, 4 groups of range switching relay switchings I/O expanded circuits V1_I/O, V2_I/O, A1_I/O with A2_I/O
It connects；ARM circuits are connected with liquid crystal, storage, keyboard and RS232 respectively；8 tunnel voltage-programmed amplifying circuit V1~V8 are respectively with 8
Road voltage signal amplitude limiter circuit, No. 4 voltage transformers/sensor signal selective relay group J1~J16, the accurate electricity of 8 tunnels sampling
Pressure mutual inductor VT1~VT8 is sequentially connected；8 tunnel voltage-programmed amplifying circuit A1~A8 respectively with No. 4 current transformers/sensor
Signal selector relay group J17~J24,8 road sample resistances, 8 tunnels sampling precision current transformer TA1~TA8 are sequentially connected.
As shown in Figures 2 and 3, using A phase voltages mutual inductor (sensor) as example explanation：
Secondary winding output access A phase a and the x voltage wiring terminals of standard potential transformer；Tested voltage transformer (passes
Sensor) secondary output access A phase 1a and 1n connecting terminals；A and x voltage wiring terminals are connected with sampling VT1 inputs, VT1 bis-
Secondary output access programmable amplifying circuit (V1)；1a and 1n connecting terminals can be selected to be inputted using sampling VT2 by relay
Still it is directly inputted into amplitude limiter circuit and programmable amplifying circuit (V2).
The foundation of selection is：Tested is that conventional voltage transformer secondary output then uses the normally closed point access sampling of relay
The output of VT2, VT2 pass through the normally closed point access amplitude limiter circuit of relay and programmable amplifying circuit (V2)；If tested is voltage sensor
Device, sensor output are small voltage signal, therefore make V1_I/O output control signals by program, make J1, J2, J3 and J4 relay
Device opened point is closed, and sensor exports small signal access amplitude limiter circuit programmable amplifying circuit (V2).
DSP gives V_A/D converter sampling enabling signals by timer internal, and the frequency of enabling signal is 50Hz × 512
=25.6kHz, 512 times of corresponding tested voltage transformer power frequency so that each cycle of measured signal can get 512
Even test A/D data.DSP reads 8 groups of V_A/D shape datas by parallel bus, and every group of V_A/D shape data is 512
It is a.DSP is by this 8 groups of V_A/D shape datas by rate conversion at the voltage value of floating type.DSP will be according to the voltage of 8 groups of floating types
8 voltage effective values, the amplification of the current automatic range switching circuit of DSP automatic decisions is calculated using real effective program in value
Whether multiple suitable, and suitable range is switched to if improper, so as to get voltage effective value V_A/D ranges 30%~
64%, the peak value of corresponding signal-under-test is within the 90% of V_A/D ranges.A phase voltages mutual inductor (sensor) automatic range
The control signal of switching and relay switching is provided by V1_I/O.
DSP will measure obtained A phase standard potential transformer floating type voltage arrays (512) and tested mutual induction of voltage
Device (sensor) floating type voltage array (512) is calculated by fast fourier transform algorithm, obtains two groups of voltage fundamentals
Virtual value and phase difference, then no-load voltage ratio, the sampling voltage by the no-load voltage ratio of standard potential transformer, tested voltage transformer are mutual
The no-load voltage ratio of sensor and the multiplying power of two-way programmable amplifying circuit are converted into ratio difference and the angle of tested voltage transformer (sensor)
Difference.
B phases, C phases and zero sequential potential transformer (sensor) workflow are with reference to A phase measurement procedures.V1_I/O is simultaneously
B phase voltages mutual inductor (sensor) range switching signal and relay switching signal are provided.V2_I/O provides C phases, zero sequence electricity
Press mutual inductor (sensor) range switching signal and relay switching signal.
As shown in Figure 4 and Figure 5, using A phase current mutual inductors (sensor) as example explanation：
Secondary winding output access A phase k1 and the k2 current wiring terminals of standard current transformer；K1 and k2 electric current wiring
Terminal is connected with the TA1 inputs of sampling precision current transformer, is generated and is taken after the accurate sample resistance Rc of bis- output accesses one of TA1
Sample voltage accesses to programmable amplifying circuit (A1).
Using A phase current mutual inductors as example explanation：
S1 the and s2 current wiring terminals of the secondary output access A phases TA of tested current transformer；A phases are tested Current Mutual Inductance
S1 the and s2 current wiring terminals of device access access an accurate sampled current transformer TA2；Bis- outputs of TA2 access another
Sampling voltage is generated after accurate sample resistance Rc to access to amplitude limiter circuit by the normally-closed contact of J17, J18 relay and program-controlled put
Big circuit (A2).
Using A phase currents sensor as example explanation：
S3 the and s4 voltage wiring terminals of the secondary output access A phases of tested current sensor；A phases
S3 and s4 voltage wiring terminals voltage accesses to amplitude limiter circuit after the normally opened contact of J17, J18 relay is closed and program-controlled puts
Big circuit (A2)；Programmable amplifying circuit (V2) input signal selection foundation be：Tested is conventional Current Transformer Secondary
The output that output is directly accessed sampling TA2, TA2 accesses amplitude limiter circuit and programmable amplifying circuit by relay normally closed contact
(A2)；If tested is current sensor, sensor output is small voltage signal, therefore makes A1_I/O output control letters by program
Number, so that J17 and J18 relay normally open contacts is closed, sensor exports small signal access amplitude limiter circuit programmable amplifying circuit (A2).
The control signal of automatic range switching is provided by A1_I/O.
DSP gives B_A/D converter sampling enabling signals by timer internal, and the frequency of enabling signal is 50Hz × 512
=25.6kHz, 512 times of corresponding tested voltage transformer power frequency so that each cycle of measured signal can get 512
Even test A/D data.DSP reads 8 groups of B_A/D shape datas by parallel bus, and every group of B_A/D shape data is 512
It is a.DSP is by this 8 groups of B_A/D shape datas by rate conversion at the voltage value of floating type.DSP will be according to the voltage of 8 groups of floating types
8 voltage effective values, the amplification of the current automatic range switching circuit of DSP automatic decisions is calculated using real effective program in value
Whether multiple suitable, and suitable range is switched to if improper, so as to get voltage effective value A/D ranges 30%~
64%, the peak value of corresponding signal-under-test is within the 90% of B_A/D ranges.
As shown in Figure 6 and Figure 7, the A phase standard current transformer floating type electric current arrays (512) that DSP obtains measurement
And tested current transformer (sensor) floating type electric current array (512) is calculated by fast fourier transform algorithm, is obtained
To the virtual value and phase difference of two groups of current first harmonics, then pass through the no-load voltage ratio of standard current transformer, tested current transformer
It is mutual that the multiplying power of the no-load voltage ratio of (sensor), the no-load voltage ratio of sampled current transformer and two-way programmable amplifying circuit is converted into tested electric current
The ratio error and angular error of sensor (sensor).
B phases, C phases and zero sequence current mutual inductor (sensor) workflow are surveyed with reference to A phase current mutual inductors (sensor)
Measure flow.A1_I/O also provides B phase current mutual inductors (sensor) range switching signal and relay switching signal simultaneously.
A2_I/O provides C phases, zero sequence current mutual inductor (sensor) range switching signal and relay switching signal.
Standard mutual inductor secondary singal I and tested mutual inductor (sensor) secondary singal I' by mathematics model analysis such as
Under：
The secondary singal of standard mutual inductor and tested mutual inductor (sensor) is obtained by A/D measurements, each period is equal
This two groups of 512 measurement data are converted into floating number, and substitute into Fast Fourier Transform (FFT) by 512 discrete signal values of even acquisition
The expression formula 1 and formula 2 of standard mutual inductor and tested mutual inductor (sensor) two groups of signals is calculated in algorithm (FFT).Expression
Signal amplitude value and initial phase containing fundametal compoment and each harmonic component in formula.
By taking current transformer is calibrated as an example：Two groups of secondary current signal warps of standard current transformer and tested current transformer
The two groups of time-domain expressions that obtain after Fourier transformation are：
Wherein：I (t) is standard current transformer secondary current signal, i'(t) it is that standard current transformer secondary current is believed
Number, InAnd I'nFor each harmonic virtual value size,WithFor the starting phase angle of each harmonic.
Tester is by software by the secondary base of the secondary fundamental signal and tested current transformer of standard current transformer
Wave signal obtains the ratio difference of tested current transformer by formula (3)；The phase of tested current transformer is obtained by formula (4)
Angular difference；
Wherein：K1To be tested the electric current ratio of current transformer, K0For the electric current ratio of standard current transformer；I0For standard electric
Current transformer fundamental wave virtual value, I'0To be tested current transformer fundamental wave virtual value；For standard current transformer fundamental wave initial phase
Position,Tested current transformer fundamental wave initial phase；f50HzIt is to be tested current transformer fundamental wave than difference, δ50HzTo be tested electric current
Mutual inductor fundamental wave angular difference value.
It is measured as current sensor or is measured as voltage transformer (sensor) to be also to use the identical meter of formula (1~4)
Calculation method, only definition have difference.
Amplitude limiter circuit is input to power supply using an amplitude limit resistance (present invention is using 20k Ω, 1W) and 2 diodes
Power supply Vdd (+12V) and Vss (- 12V).When external input signal is more than ± 12.6V, diode current flow, by programming amplifying electricity
The input voltage on road is clamped down between ± 12.6V, will not cause excessive pressure damages to the amplifying circuit and A/D of rear class.Amplitude limit resistance
150V voltages can be born for a long time, it well will be due to the software setting damage caused to equipment circuit different with practical access signal
It is bad.If instrument is in off-mode, Vdd and Vss are 0V, and can bear 140V voltages for a long time at this time will not be to circuit and element
Damage.A2_I/O provides C phases, zero sequence current mutual inductor (sensor) range switching signal and relay switching signal.Two
The data of A/D converter are read by simultaneously data/address bus by DSP.
It uses ARM to realize human-computer interaction for core processor, liquid crystal display, display related interfaces sum number can be driven
According to, the dependent instruction of calibration personnel can be inputted by keyboard, can also be by serial ports and computer communication, realization is by computer
The automatic measurement data for obtaining calibrating installation, can also carry out data management.ARM is that the human-computer interaction module of core processor will
The basic parameter of the input of calibration personnel issues data processing module DSP.
Data processing module is designed by the processor of DSP core, is the key that device observing and controlling component.Data processing module needs
It will be calculated into line program than difference and angular difference value according to setup parameter in human-computer interaction module ARM.Data processing module
Final survey calculation result is sent to human-computer interaction core ARM, ARM on the results are shown in liquid crystal or is stored in and deposits by DSP
On reservoir.
Use ARM frameworks, Peripheral Interface abundant in device.Processing speed reaches 66MHz, helps to reduce the system applied
Grade cost.Fully meet this system design requirement.The A/D converter used in device uses high-speed parallel successive approximation A/
D conversion circuits are that high integration, 8 channel parallel high-speed synchronous are adopted using 16 A/D acquisition chip AD7606 of ADI companies
Sample, 16bit Approach by inchmeal (SAR) type ADC.
As shown in figure 9, for wherein A/D circuit diagrams, two-way A/D schematic diagrams are identical all the way.
A/D circuit digital part of interface：The bus of wherein D0~D15 and DSP connects；The timer of/COVST and DSP is defeated
Go out pin connection, for starting A/D samplings；/ AD-END connects the interrupting input mouth of DSP, passes through interruption after being sampled for A/D
Mouth makes DSP enter interrupt handling routine, and DSP reads out A/D measured values after entering interrupt handling routine；/ CS-7606 is piece
Select signal；/ RES_7606 is reset signal；/ RD is that bus reads signal；+ 5VA2 is bus driver power supply；
A/D breadboardin part of interface：CH1~CH8 is analog measurement input；AVCC be simulation power supply interface, AGND,
V1GND~V8GND is ground interface；Two APL117.5V three-terminal voltage-stabilizing power supplys are used to export two independent 5V as A/D chips
Power supply, wherein all the way+5VA be simulation power supply, another way+5VA2 is digital power system；With AD780 fiducial chips export 2.5V to
A/D chips are as reference voltage REF.
Simulation ground AGND and digitally GND is in A/D chip bottom short circuits.
There are two-way 5V, two groups of ± 12V power supplys using power module in device, each other equal electrical isolation.5V all the way
Power supply is powered to DSP and ARM, and 5V power supplys are powered to I/O expanded circuits all the way.One of which ± 12V power supplys are to current transformer
(sensor) programmable amplifying circuit and current channel A_A/D power supplies, another group of ± 12V power supply give voltage transformer (sensor) journey
Control amplifying circuit and voltage channel U_A/D power supplies.
As shown in figure 8, programmable amplifying circuit is amplified using programme control precision divider resistance chip MAX5431 and high performance computation
Device OP2177 is realized.MAX5431 uses 2 digital signal lines that can select 1 road divider resistance coefficient with 4, and 1,2,4,8 are realized with amplifier
Enlargement ratio.Gain accuracy is 0.025%.The programmable amplifying circuit of each measurement object uses three groups of amplifying circuits,
Realize that 1,2,4,8,16,32,64,128,256,512 enlargement ratios, the verification demand for meeting S grades of current transformers (need
1% operating current point tests the error of current transformer).
Voltage-programmed amplifying circuit specifically includes：First operational amplifier, second operational amplifier, third operation amplifier
Device, four-operational amplifier, the first programme control precision divider resistance chip N1, the second programme control precision divider resistance chip N2 and third
Programme control precision divider resistance chip N3；The output end of first operational amplifier connects the first programme control precision divider resistance chip N1's
The inverting input of 2 pins, the first operational amplifier is connected to the output end and the first programme control precision point of the first operational amplifier
Between 2 pins of piezoresistance chip N1, the normal phase input end of the first operational amplifier connects KD；First programme control precision divider resistance
The normal phase input end of the 6 pins connection second operational amplifier of chip N1,8 pins of the first programme control precision divider resistance chip N1
The inverting input of second operational amplifier is connected, the output end of second operational amplifier connects the second programme control precision divider resistance
2 pins of chip N2,4 pins of the first programme control precision divider resistance chip N1 be connected to the output end of second operational amplifier with
Between 2 pins of second programme control precision divider resistance chip N2；The 6 pins connection the of second programme control precision divider resistance chip N2
8 pins of the normal phase input end of three operational amplifiers, the second programme control precision divider resistance chip N2 connect third operational amplifier
Inverting input, 2 pins of the output end connection third programme control precision divider resistance chip N3 of third operational amplifier, second
4 pins of programme control precision divider resistance chip N2 are connected to the output end and third programme control precision partial pressure electricity of third operational amplifier
Between 2 pins for hindering chip N3；The positive of the 6 pins connection four-operational amplifier of third programme control precision divider resistance chip N3
Input terminal, the inverting input of the 8 pins connection four-operational amplifier of third programme control precision divider resistance chip N3, the 4th fortune
The output end for calculating amplifier connects KDFA, and 4 pins of third programme control precision divider resistance chip N3 are connected to the 4th operation amplifier
Between the output end and KDFA of device.
The present invention tests without error of measurement test circuit, and wiring is simple.Single-phase voltage (electric current) mutual inductor can be verified.
It may be implemented to verify while three-phase voltage+threephase current transformer in combination transformer, be more in line with the reality of combination transformer
Border working condition.One or two verifications for merging the three-phase+zero sequential potential transformer used in distribution may be implemented, can also realize
Three-phase current+zero sequence current mutual inductor verification.Three-phase+residual voltage sensor that one or two fusions use in distribution may be implemented
Verification, can also realize the verification of three-phase current+zero sequence current sensor.
The present invention uses the direct method of measurement, used sampling precision current (voltage) mutual inductor, sampling precision resistance
And measuring circuit is high precision grade high stability device or circuit, stable testing is reliable, can reach 0.05 grade of voltage, electricity
0.05S grades of stream.Meet the verification of 0.2 grade of (0.2S) following voltage (electric current) mutual inductor (sensor).It is embedding using the direct method of measurement
Angular difference value can be directly obtained by entering formula software, accepted standard voltage (electric current) mutual inductor can with test item different voltages ratio or
Calculating and display than difference can be realized by no-load voltage ratio conversion in electric current ratio.
The expanded function 1 of the present invention voltage channel can will be inputted as standard potential transformer all the way, other 7 tunnels are all
It is inputted as tested voltage transformer, may be implemented to use 1 standard potential transformer at most while 7 tested voltages of verification are mutual
The error of sensor or winding.Expanded function 2 voltage channel can will input, the small signal in 4 tunnels as standard potential transformer all the way
Channel is directly inputted all as electronic voltage transducer input is tested, and may be implemented most using 1 standard potential transformer
The error of 4 tested voltage sensors is verified simultaneously.Expanded function 3 can will be made in precision current transformer sampling channel all the way
It is inputted for standard current transformer, other 7 tunnels all as current transformer input is tested, may be implemented to use 1 normalized current
Mutual inductor at most verifies the error of 7 tested current transformers simultaneously.Expanded function 4, can will precision current transformer all the way
It samples channel to input as standard current transformer, the small signal in 4 tunnels directly inputs channel and all senses as tested electronic current
Device inputs, and may be implemented to use 1 standard current transformer at most while verifying the error of 4 tested current sensors.
Claims (5)
1. a kind of multichannel directly measures formula mutual-inductor tester, which is characterized in that including：DSP circuit, ARM circuits, liquid crystal,
Keyboard, storage, RS232, power supply, 8 tunnels sampling accurate voltage mutual inductor VT1~VT8,8 tunnels sampling precision current transformer TA1~
TA8,8 road sample resistance Rc, 8 road voltage signal amplitude limiter circuits, No. 4 voltage transformers/sensor signal selective relay group J1
~J16, No. 4 current transformers/sensor signal selective relay group J17~J24,16 tunnel voltage-programmed amplifying circuit V1~V8
16 A/D circuits V_A/D and A_A/D, 4 groups of range switching relay switching I/O extensions are sampled with A1~A8,28 channel parallels
Circuit V1_I/O, V2_I/O, A1_I/O and A2_I/O, all in the Aluminum Alloy Chassis of a 4U standard；DSP circuit point
16 A/D circuits V_ are not sampled with ARM circuits, 16 tunnel voltage-programmed amplifying circuit V1~V8 and A1~A8,28 channel parallels
A/D is connected with A_A/D, 4 groups of range switching relay switchings I/O expanded circuits V1_I/O, V2_I/O, A1_I/O with A2_I/O
It connects；ARM circuits are connected with liquid crystal, storage, keyboard and RS232 respectively；8 tunnel voltage-programmed amplifying circuit V1~V8 are respectively with 8
Road voltage signal amplitude limiter circuit, No. 4 voltage transformers/sensor signal selective relay group J1~J16, the accurate electricity of 8 tunnels sampling
Pressure mutual inductor VT1~VT8 is sequentially connected；8 tunnel voltage-programmed amplifying circuit A1~A8 respectively with No. 4 current transformers/sensor
Signal selector relay group J17~J24,8 road sample resistances, 8 tunnels sampling precision current transformer TA1~TA8 are sequentially connected.
2. multichannel as described in claim 1 directly measures formula mutual-inductor tester, which is characterized in that voltage-programmed amplification electricity
Road specifically includes：First operational amplifier, second operational amplifier, third operational amplifier, four-operational amplifier, the first journey
The accurate divider resistance chip N1 of control, the second programme control precision divider resistance chip N2 and third programme control precision divider resistance chip N3；
The output end of first operational amplifier connects 2 pins of the first programme control precision divider resistance chip N1, the first operational amplifier
Inverting input be connected to the first operational amplifier output end and the first programme control precision divider resistance chip N1 2 pins it
Between, the normal phase input end of the first operational amplifier connects KD；The 6 pins connection second of first programme control precision divider resistance chip N1
The normal phase input end of operational amplifier, the 8 pins connection second operational amplifier of the first programme control precision divider resistance chip N1
Inverting input, the output end of second operational amplifier connect 2 pins of the second programme control precision divider resistance chip N2, the first journey
4 pins of the accurate divider resistance chip N1 of control are connected to the output end and the second programme control precision divider resistance of second operational amplifier
Between 2 pins of chip N2；The positive of the 6 pins connection third operational amplifier of second programme control precision divider resistance chip N2 is defeated
Enter end, the inverting input of the 8 pins connection third operational amplifier of the second programme control precision divider resistance chip N2, third operation
2 pins of the output end connection third programme control precision divider resistance chip N3 of amplifier, the second programme control precision divider resistance chip
4 pins of N2 are connected between the output end of third operational amplifier and 2 pins of third programme control precision divider resistance chip N3；
The normal phase input end of the 6 pins connection four-operational amplifier of third programme control precision divider resistance chip N3, third programme control precision
The inverting input of the 8 pins connection four-operational amplifier of divider resistance chip N3, the output end of four-operational amplifier connect
Meet KDFA, 4 pins of third programme control precision divider resistance chip N3 be connected to four-operational amplifier output end and KDFA it
Between.
3. multichannel as described in claim 1 directly measures formula mutual-inductor tester, which is characterized in that 28 channel parallels are adopted
16 A/D circuits of sample are specially：A/D circuit digital part of interface：The bus of wherein D0~D15 and DSP connects ,/COVST with
The timer output pin of DSP connects, and for starting A/D samplings ,/AD-END connects the interrupting input mouth of DSP, is sampled for A/D
After so that DSP is entered interrupt handling routine by middle fracture, DSP reads out A/D measured values after entering interrupt handling routine
Come ,/CS-7606 is chip selection signal, and/RES_7606 is reset signal, and/RD is that bus reads signal, and+5VA2 is bus driver electricity
Source；A/D breadboardin part of interface：CH1~CH8 is analog measurement input, and AVCC is simulation power supply interface, AGND, V1GND
~V8GND is ground interface, and two APL117.5V three-terminal voltage-stabilizing power supplys is used to export confessions of two independent 5V as A/D chips
Electricity, wherein+5VA is simulation power supply all the way, another way+5VA2 is digital power system, and 2.5V is exported to A/D with AD780 fiducial chips
Chip is as reference voltage REF；Simulation ground AGND and digitally GND is in A/D chip bottom short circuits.
4. a kind of multichannel directly measures the method for calibration of formula mutual-inductor tester, which is characterized in that include the following steps：
(1) tester measures the secondary output voltage or electric current of voltage transformer or current transformer, each channel voltage respectively
Synchronous 512 A/D of a cycle that obtain measure shape data；
(2) tester calculates the amplitude size and phase difference of each channel voltage by cured software in DSP circuit, in turn
The ratio difference and angular difference of standard potential transformer or current transformer and tested voltage transformer or current transformer is calculated
Value.
5. multichannel as claimed in claim 4 directly measures the method for calibration of formula mutual-inductor tester, which is characterized in that step
(2) in, tester obtains the secondary singal of standard mutual inductor and tested mutual inductor or sensor, Mei Gezhou by A/D measurements
Phase uniformly obtains 512 discrete signal values, this two groups of 512 measurement data is converted into floating number, and substitute into fast Fourier
Become the expression formula that standard mutual inductor and tested mutual inductor (sensor) two groups of signals is calculated in scaling method FFT；In expression formula
Signal amplitude value and initial phase containing fundametal compoment and each harmonic component；
Two groups of secondary current signals of standard current transformer and tested current transformer be fourier transformed after obtain two groups
Time-domain expression is：
Wherein：I (t) is standard current transformer secondary current signal, i'(t) it is standard current transformer secondary current signal, In
And I'nFor each harmonic virtual value size,WithFor the starting phase angle of each harmonic；
Tester is believed the secondary fundamental wave of the secondary fundamental signal of standard current transformer and tested current transformer by software
Number obtain the ratio difference of tested current transformer by formula (3)；The phase angle of tested current transformer is obtained by formula (4)
Difference；
Wherein：K1To be tested the electric current ratio of current transformer, K0For the electric current ratio of standard current transformer；I0It is mutual for normalized current
Sensor fundamental wave virtual value, I'0To be tested current transformer fundamental wave virtual value；For standard current transformer fundamental wave initial phase,
To be tested current transformer fundamental wave initial phase；f50HzIt is to be tested current transformer fundamental wave than difference, δ50HzTo be tested Current Mutual Inductance
Device fundamental wave angular difference value；It is measured as current sensor or is measured as voltage transformer or voltage sensor method class with being measured as electric current
Mutual inductor.
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