CN109541506A - A kind of measurement of power transformer iron core magnetic characteristic and analytical equipment - Google Patents
A kind of measurement of power transformer iron core magnetic characteristic and analytical equipment Download PDFInfo
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- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
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Abstract
The invention discloses a kind of measurement of power transformer iron core magnetic characteristic and analytical equipments, comprising: voltage acquisition module, current acquisition module, magnetic flux acquisition module, frequency generator module, electrical isolation module, central processing module and failure protection module；Frequency generator module is according to the signal of acquisition, generate the pulse signal of synchronized sampling, data after sampling are after A/D is converted, it is digital signal by analog-signal transitions, digital data transmission is into central processing module, the band modified automatic integration of baseline is carried out to voltage signal, magnetic flux signal is calculated, data conversion is carried out to current signal, magnetic field strength is calculated, magnetic induction intensity is calculated by numerical value conversion to magnetic flux signal, solves the problems, such as that the prior art is tested and analyzed to power transformer iron core remanent magnetism.
Description
Technical field
This application involves a kind of power transformer testing fields, and in particular to a kind of power transformer iron core magnetic characteristic test
Amount and analytical equipment, while being related to a kind of test of power transformer iron core magnetic characteristic and analysis method.
Background technique
Transformer is a kind of stationary motor based on electromagnetic induction principle, for different voltages grade voltage conversion or every
From AC power source, power transformer is extremely important main electrical equipment in electric system, and whether it can work normally direct pass
It is the continuous and steady operation to electric system.If transformer, since failure damages, maintenance difficulty is big, the period is long, not only
The normal operation of electric system is influenced, or even will cause immeasurable economic loss and social influence.Ferromagnetic material is as electricity
The important component of power transformer plays an important role in electric energy transmission, conversion, directly affects the property of electrical equipment
Energy and reliability.
Power transformer after a failure grasp than measurement, no-load test and multiple switching by random separating brake, direct resistance metering, voltage
Under the conditions of making etc., remanent magnetism can be generated in the minds of transformer fe, wherein random separating brake is surplus for iron core after direct resistance metering and failure
The main source of magnetic, the size of remanent magnetism amount and the capacity of transformer, separating brake angle, direct current size etc. are related.If not to surplus
Magnetic is handled, may protective relaying device to power transformer and primary equipment bring many adverse effects.Such as:
(1) it closes a floodgate and is powered in the case where power transformer underloading or zero load, the presence of the remanent magnetism in iron core can accelerate power transformer
Core sataration is saturated electrical transformer cores half cycle, and there are a large amount of harmonic waves in the exciting current of generation, i.e. the presence of remanent magnetism will
The appearance for leading to power transformer excitation surge current, the value shoved is up to several times of rated current or more than ten times；(2) asymmetric
Excitation surge current increases added losses in iron core in winding and hardware, generate additional heat, also increase power transformer
The reactive power consumption of device, while the height saturation of iron core increases leakage field, causes fuel tank to overheat, hot-spot will make insulating paper old
Change, the service life for influencing power transformer even causes permanent lesion to it；(3) higher shove can generate overvoltage and cause to break
Device tripping in road even burns device, brings many adverse effects to power transformer and power grid；(4) excitation surge current makes in electricity
Contain odd number and even-order harmonic in Force system, these harmonic waves can lead to the increase of the stray loss in power transformer, cause hair
The incorrect tripping etc. of relay in motor and capacitive filter group.Currently, the research of the remanent magnetism to transformer, mainly surplus
The identification for the excitation surge current that magnetic generates and remanent magnetism technology for eliminating, both lack one can residual induction for reference, there are one
Fixed blindness can be transformer demagnetization and failure by the remanent magnetism of the iron core of transformer under analysis different condition
Phase selection provides a reference afterwards, simplifies operating process.
For the measurement and assessment of transformer remanent magnetism, it common are following three kinds: (1) empirical value method, it is considered that test
Remanent magnetism is 20% to 80% saturation flux value range after operation；(2) preliminary filling magnetic method, to iron core load excitation to one it is biggish
Then the flux value known is analyzed so that original remanent magnetism is capped based on new known remanent magnetism；(3) communicating DC method,
By applying the direct current of positive negative sense, makes magnetic flux reach positive, negative sense saturation respectively, analyze remanent magnetism.In view of empirical value method
With very big randomness, preliminary filling magnetic method and communicating DC method have that the electric current that magnetizes is big, reaches for high-power transformer
To the disadvantage that the magnetic saturation time is long, operability is not strong, there is power transformer iron core measurement of residual magnetism and analysis in the prior art
Deficiency, have much room for improvement promotion.
Summary of the invention
The application provides a kind of power transformer iron core magnetic characteristic test volume and analytical equipment, can effectively solve the prior art
The problem of power transformer iron core remanent magnetism is tested and is analyzed.
The application provides a kind of measurement of power transformer iron core magnetic characteristic and analytical equipment characterized by comprising
Voltage acquisition module, current acquisition module, magnetic flux acquisition module, frequency generator module, electrical isolation module, in
Entreat processing module and failure protection module；After device starting, channels of information acquisition acquires electric power by voltage acquisition module and becomes
The voltage signal of depressor；The current signal of power transformer is acquired by current acquisition module；It is acquired by magnetic flux acquisition module
The magnetic flux signal of power transformer；Frequency generator module generates the pulse signal of synchronized sampling according to the signal of acquisition, feedback
Synchronized sampling is realized to sampling channel, and analog-signal transitions are digital signal, led to by the data after sampling after A/D is converted
Electrical isolation module is crossed, realizes electrical isolation；Digital data transmission carries out band baseline into central processing module, to voltage signal
Magnetic flux signal is calculated in modified automatic integration, carries out data conversion to current signal and magnetic field strength is calculated, to magnetic flux
Magnetic induction intensity is calculated by numerical value conversion in signal；Digital signal is transmitted to failure protection module, according to preset
The max-thresholds of signal measurement range carry out the out-of-limit judgement of threshold value.
Preferably, further includes:
Data disaply moudle, for showing real-time voltage signal, current signal and magnetic communication by touching display screen
Number waveform change curve, can also show voltage signal, current signal magnetic field intensity signal magnetic flux signal, magnetic induction intensity letter
Number virtual value；Touching display screen can be to the range, high-pressure side umber of turn, low-pressure side umber of turn, magnetic circuit of voltage measurement
The parameters such as length, area of core section are configured.
Preferably, further includes:
Data memory module, for saving the data of test and analysis, there are in the memory of system.
Preferably, further includes:
Communication module is realized by way of PC software to test for the communication between PC machine measurement and analytical equipment
Control；Also the export function that data may be implemented exports to the data of preservation in system memory in external storage equipment.
Preferably, further includes:
Function resets module, for eliminating influence of the previous test data to test result next time.
Preferably, the digital signal is transmitted to failure protection module, most according to preset signal measurement range
Big threshold value, after the step of carrying out threshold value out-of-limit judgement, further includes:
If out-of-limit, then system prompt early warning occurs, and show warning on data disaply moudle by the out-of-limit judgement of threshold value
Mark.
Preferably, described voltage signal to be carried out magnetic flux signal is calculated with the modified automatic integration of baseline, specifically
Calculation formula are as follows:
In formula: ΦAX、Φax: the magnetic flux of high-pressure side winding, low-pressure side winding, unit are weber (Wb)； UAX、Uax: it is high
The voltage of side winding, low-pressure side winding is pressed, unit is volt (V)；T: sampling total time, unit are second (S).
It is preferably, described that magnetic field strength, specific calculation formula are calculated to current signal progress data conversion are as follows:
Wherein:
H: magnetic field strength when excitation, unit are amperes per meter (A/m)；
N1: the number of turns of high-pressure side winding, dimensionless；
IAX: the exciting current of high-pressure side winding, unit are ampere (A)；
Le: transformer equivalent magnetic circuit length, unit rice (m).
It is preferably, described that magnetic induction intensity, specific calculation formula are calculated by numerical value conversion to magnetic flux signal are as follows:
Wherein:
BAX、Bax: the magnetic induction intensity of high-pressure side winding, low-pressure side winding, unit are tesla (T)；
ΦAX、Φax: the magnetic flux of high-pressure side winding, low-pressure side winding, unit are weber (Wb)；
N1、N2: high-pressure side winding, low-pressure side umber of turn, dimensionless；
Ae: the equivalent cross-sectional area of iron core, unit are square metre (m2)。
The application provides a kind of measurement of power transformer iron core magnetic characteristic and analysis method simultaneously characterized by comprising
Acquire voltage signal, current signal and the magnetic flux signal of power transformer；And by the voltage signal, electric current
Signal and magnetic flux signal are transferred to frequency generator module；
Frequency generator module will generate synchronized sampling according to the voltage signal, current signal and magnetic flux signal
Pulse train realizes synchronized sampling, and analog-signal transitions are digital signal after A/D is converted by the data after sampling, described
Digital signal realizes electrical isolation by electrical isolation module；
The digital data transmission is to CPU module, and CPU module is to the voltage in the digital signal
Signal carries out the band modified automatic integration of baseline and magnetic flux signal is calculated, and carries out data conversion to current signal and magnetic is calculated
Magnetic induction intensity is calculated by numerical value conversion to magnetic flux signal in field intensity；
The digital data transmission is to failure protection module, according to the max-thresholds of preset signal measurement range,
Carry out the out-of-limit judgement of threshold value.
This application provides a kind of power transformer iron core magnetic characteristic test volume and analytical equipments, by obtaining transformer
Alternating current and direct current magnetization characteristic, and based on this, the remanent magnetism after analyzing straight resistance test, is the remanent magnetism point of transformer
Analysis and demagnetization processing provide a remanent magnetism reference value, can effectively solve the prior art to power transformer iron core remanent magnetism test and
The problem of analysis.
Detailed description of the invention
Fig. 1 is power transformer iron core magnetic characteristic measurement provided by the present application and analytical equipment technology frame chart；
Fig. 2 is that the invention relates to be drive module in A/D conversion module；
Fig. 3 be the invention relates to transformer AC excitation performance diagram；
Fig. 4 be the invention relates to transformer DC magnetization curve figure；
Fig. 5 be the invention relates to injection different DC DC Resistance Test of Transformer after remanent magnetism change
Change curve；
Fig. 6 is power transformer iron core magnetic characteristic measurement provided by the embodiments of the present application and analysis method flow chart.
Specific embodiment
Many details are explained in the following description in order to fully understand the application.But the application can be with
Much it is different from other way described herein to implement, those skilled in the art can be without prejudice to the application intension the case where
Under do similar popularization, therefore the application is not limited by following public specific implementation.
The technology frame chart of power transformer iron core magnetic characteristic test and analytical equipment, as shown in Figure 1, can from figure
Out, device provided by the present application specifically includes that voltage acquisition module, current acquisition module, magnetic flux acquisition module, frequency generator
Module, electrical isolation module, central processing module and failure protection module；After device starting, channels of information acquisition passes through electricity
Press the voltage signal of acquisition module acquisition power transformer；The current signal of power transformer is acquired by current acquisition module；
The magnetic flux signal of power transformer is acquired by magnetic flux acquisition module；Frequency generator module generates same according to the signal of acquisition
The pulse signal for walking sampling feeds back to sampling channel and realizes synchronized sampling, and the data after sampling will be simulated after A/D is converted
Signal is changed into digital signal, by electrical isolation module, realizes electrical isolation；Digital data transmission is to central processing module
In, voltage signal is carried out to obtain magnetic flux signal from integral calculation with what baseline was modified, data conversion meter is carried out to current signal
Calculation obtains magnetic field strength, and magnetic induction intensity is calculated by numerical value conversion to magnetic flux signal；Digital signal is transmitted to failure guarantor
Module is protected, according to the max-thresholds of preset signal measurement range, carries out the out-of-limit judgement of threshold value.
Device provided by the present application further include:
Data disaply moudle, for showing real-time voltage signal, current signal and magnetic communication by touching display screen
Number waveform change curve, can also show voltage signal, current signal magnetic field intensity signal magnetic flux signal, magnetic induction intensity letter
Number virtual value；Touching display screen can be to the range, high-pressure side umber of turn, low-pressure side umber of turn, magnetic circuit of voltage measurement
The parameters such as length, area of core section are configured.
Data memory module, for the data of test and analysis to be stored in the memory of system.
Communication module is realized by way of PC software communication for the communication between PC machine and measurement and analytical equipment
Control to test；The data of preservation in system memory are exported to external storage by the transfer function that data also may be implemented
In equipment.
Function resets module, for eliminating influence of the previous test data to test result next time.
The digital signal is transmitted to failure protection module, according to the max-thresholds of preset signal measurement range,
After the step of carrying out threshold value out-of-limit judgement, further includes:
If out-of-limit, then system prompt early warning occurs, and show warning on data disaply moudle by the out-of-limit judgement of threshold value
Mark.
It is described voltage signal to be carried out magnetic flux signal, specific calculation formula is calculated with the modified automatic integration of baseline
Are as follows:
In formula: ΦAX、Φax: the magnetic flux of high-pressure side winding, low-pressure side winding, unit are weber (Wb)； UAX、Uax: it is high
The voltage of side winding, low-pressure side winding is pressed, unit is volt (V)；T: sampling total time, unit are second (S).
It is described that magnetic field strength, specific calculation formula are calculated to current signal progress data conversion are as follows:
Wherein:
H: magnetic field strength when excitation, unit are amperes per meter (A/m)；
N1: the number of turns of high-pressure side winding, dimensionless；
IAX: the exciting current of high-pressure side winding, unit are ampere (A)；
Le: transformer equivalent magnetic circuit length, unit rice (m).
It is described that magnetic induction intensity, specific calculation formula are calculated by numerical value conversion to magnetic flux signal are as follows:
Wherein:
BAX、Bax: the magnetic induction intensity of high-pressure side winding, low-pressure side winding, unit are tesla (T)；
ΦAX、Φax: the magnetic flux of high-pressure side winding, low-pressure side winding, unit are weber (Wb)；
N1、N2: high-pressure side winding, low-pressure side umber of turn, dimensionless；
Ae: the equivalent cross-sectional area of iron core, unit are square metre (m2)。
Device provided by the present application is described in detail in conjunction with specific embodiment below.
Embodiment one: power transformer AC excitation feature measurement
Using certain model 3kV transformer model as measurement object, illustrate to measure transformation using technical solution of the present invention
The process of device AC excitation characteristic.
A kind of measurement of power transformer iron core magnetic characteristic and analytical equipment, include following functions module:
(1) voltage acquisition module: logical by being connected to the AC voltage sampling of high-pressure side and low-pressure side in transformer model
Road acquires the voltage signal U of high-pressure side and low-pressure sideAX、Uax, after enhanced processing and A/D conversion, converted by A/D
Drive module in module is transferred to real-time display U-t curve in data display screen, and shows respectively on data display screen
Corresponding virtual value.A/D conversion is completed by the drive module in A/D conversion module, please refers to Fig. 2.This application involves
A/D conversion is all completed by drive module as shown in Figure 2.
(2) it current acquisition module: by the AC current collecting channel being connected in transformer model high pressure side loop, adopts
Collect on high-tension side exciting current I signal, after enhanced processing and A/D conversion, is transferred to real-time display in data display screen
I-t curve, and corresponding virtual value is shown on data display screen.
(3) magnetic-flux measurement module: led to by being connected to the exchange flux of high-pressure side and low-pressure side in transformer model and acquiring
Road acquires the voltage signal U of high-pressure side and low-pressure sideAX、Uax, after enhanced processing and A/D conversion, it is transferred to central fortune
Control module is calculated, carries out signal integration processing (the base wavelet operation of real-time perfoming integrated signal in integral process), obtains height
Press the magnetic flux signal Phi of side and low-pressure sideAX、Φax, it is transferred to real-time display Φ-t curve in data display screen, and aobvious in data
Corresponding peak value is shown in display screen respectively.
(4) frequency generator module: frequency generator can manually set the frequency of sampling and the averagely counting of sampling, produce
The clock trigger signal of raw Five-channel sampling, realizes synchronized sampling.
(5) electrical isolation module: being converted by A/D, by the analog signal of high voltage, high current be converted to it is low level from
Dissipate digital signal, the safety in protection circuit.
(6) central processing module: the signal of each channel acquisition is transferred in central processing module, carries out further
Operational analysis, including voltage signal U automatic integration operation, the numerical value conversion of current signal I, the display control of touch screen, U-t,
Storage and export of display control, data that I-t, Φ-t draw etc..
(7) " threshold value is out-of-limit " comparison failure protection module: is carried out by voltage signal U, the current signal I that will acquire respectively
Analysis, monitors the state of measurement, if measuring signal is out-of-limit, system early warning, and warning mark is shown in display screen.
(8) data disaply moudle: voltage signal U, current signal I after acquisition process, magnetic flux signal Phi can pass through
Data disaply moudle exports in real time.
(9) data memory module: the signal data after acquisition process is by column storage, including time Time, voltage U, electric current
I, magnetic flux Φ.
(10) communication module: this measuring device use three kinds of general interfaces, USB interface, LAN interface, RS232 interface,
It can be selected according to the actual situation in measurement.
(11) function resets module: every time before measurement, can click " clearing " button, measurement data is zeroed out school
Standard guarantees that the secondary measurement result is not influenced by a preceding measurement result.
The AC excitation for measuring certain model 3kV transformer model using a kind of power transformer iron core magnetic characterization devices is special
Property, it mainly comprises the steps that
Step 1: test loop is built, according to Fig. 5 mode connecting test circuit, on high-tension side voltage rating U1NFor base
Standard gives the driving voltage U of high voltage side of transformerk, when the value of k be followed successively by k=10%, 30%, 50%, 70%, 90%,
95%, 100%, 105%, 110%, 115%, 120% when, corresponding UkRespectively Uk=10%U1N, 30%U1N, 50%U1N、
70%U1N, 90%U1N, 95%U1N, 100%U1N, 105%U1N, 110%U1N, 115%U1N, 120%U1NTotal 11 default
Value applies driving voltage to transformer one by one；
Step 2: clicking " test " button, start the data acquisition function of test macro.Acquire high voltage side of transformer, low pressure
The voltage waveform signal U of sideAX、Uax, pass through high-pressure side UAXWhether the voltage that signal can monitor application reaches preset value, acquisition
Excitation current waveform signal IAX；
Step 3: the signal of acquisition is converted by enhanced processing and A/D, analog signal is transformed to digital signal, and will be electric
Pressure and current digital signal are transferred to central processing module, carry out the calculating analysis of data.
Step 4: " threshold value is out-of-limit " judgement, voltage signal U are transferred in central processing module, first progress " threshold value is out-of-limit "
Analysis, if the signal of acquisition exceeds threshold value (the voltage threshold U of defaultmax=500V, current threshold Imax=33A), then
System issues early warning, identifies display early warning on display screen, if returning again to step 5 without departing from the threshold value of default；
Step 5: automatic integration calculation processing, the voltage signal U collected are accumulated automatically in central processing module
Partite transport is calculated, and corresponding high-pressure side, low-pressure side magnetic flux Φ are obtainedAX、Φax, the formula of calculating is shown in formula (1)；Current signal I transmission
Into central processing module, data conversion calculation processing is carried out, obtains magnetic field strength H, the formula of calculating is shown in formula (2)；Magnetic flux
Signal obtains magnetic induction density B using data conversion treatment, and calculation formula is shown in formula (3).
In formula: ΦAX、Φax: the magnetic flux of high-pressure side winding, low-pressure side winding, unit are weber (Wb)；UAX、Uax: high pressure
The voltage of side winding, low-pressure side winding, unit are volt (V)；T: sampling total time, unit are second (S).
Wherein:
H: magnetic field strength when excitation, unit are amperes per meter (A/m)；
N1: the number of turns of high-pressure side winding, dimensionless；
IAX: the exciting current of high-pressure side winding, unit are ampere (A)；
Le: transformer equivalent magnetic circuit length, unit rice (m).
Wherein:
BAX、Bax: the magnetic induction intensity of high-pressure side winding, low-pressure side winding, unit are tesla (T)；
ΦAX、Φax: the magnetic flux of high-pressure side winding, low-pressure side winding, unit are weber (Wb)；
N1、N2: high-pressure side winding, low-pressure side umber of turn, dimensionless；
Ae: the equivalent cross-sectional area of iron core, unit are square metre (m2)。
Step 6: data save, and save function by data, treated data are saved as txt text；
Step 7: clicking " clearing " button, the data of the secondary measurement are subjected to operation and reset calibration (in calculation process mode
Logic zero clearing, delete operation is not carried out to the data that store in step 5), the measurement result for guaranteeing next time is not superimposed previous
The influence of secondary measurement result.It is re-execute the steps 1-7, works as k=120%, Uk=120%UNWhen, go to step 8；
Step 8: data being obtained according to step 1-7, choose low-pressure side magnetic induction density Bax, magnetic field strength H, draw different electricity
The B-H hysteresis loop under grade is pressed, the AC Hysteresis Loop cluster of the transformer model is obtained, as shown in Fig. 3-(a), according to obtaining
Hysteresis loop cluster can draw out the ac magnetization curve of the transformer model, as shown in Fig. 3-(b).
Step 9: clicking " preservation " button, save test data, then click " System menu ", " data export " is selected to press
Button exports to the data of preservation in USB flash device.
Step 10: shutdown test system disassembles test loop, terminates test.
Case two: power transformer DC magnetizing characteristic measurement
Using a 3kV transformer model as measurement object, illustrate to utilize technical solution of the present invention measuring transformer direct current
The process of magnetization characteristic.
A kind of measurement of power transformer iron core magnetic characteristic and analytical equipment, include following functions module:
(1) voltage acquisition module: led to by being connected to the DC voltage of high-pressure side and low-pressure side in transformer model and acquiring
Road acquires the voltage signal U of high-pressure side and low-pressure sideAX、Uax, after enhanced processing and A/D conversion, it is aobvious to be transferred to data
Real-time display U-t curve in display screen, and show corresponding virtual value respectively on data display screen.
(2) it current acquisition module: by the DC current acquisition channel being connected in transformer model high pressure side loop, adopts
Collect on high-tension side exciting current I signal, after enhanced processing and A/D conversion, is transferred to real-time display in data display screen
I-t curve, and corresponding virtual value is shown on data display screen.
(3) magnetic-flux measurement module: led to by being connected to the direct current flux of high-pressure side and low-pressure side in transformer model and acquiring
Road acquires the voltage signal U of high-pressure side and low-pressure sideAX、Uax, after enhanced processing and A/D conversion, it is transferred to central fortune
Control module is calculated, carries out signal integration processing (the base wavelet operation of real-time perfoming integrated signal in integral process), obtains height
Press the magnetic flux signal Phi of side and low-pressure sideAX、Φax, it is transferred to real-time display Φ-t curve in data display screen, and aobvious in data
Corresponding peak value is shown in display screen respectively.
(4) frequency generator module: frequency generator can pass through the benchmark of selection voltage signal U or current signal I
Contrast signal generates the clock trigger signal of Five-channel sampling, realizes synchronized sampling.
(5) electrical isolation module: being converted by A/D, by the analog signal of high voltage, high current be converted to it is low level from
Dissipate digital signal, the safety in protection circuit.
(6) central processing module: the signal of each channel acquisition is transferred in central processing module, carries out further
Operational analysis, including voltage signal U automatic integration operation, the numerical value conversion of current signal I, the display control of touch screen, U-t,
Storage and export of display control, data that I-t, Φ-t draw etc..
(7) " threshold value is out-of-limit " comparison failure protection module: is carried out by voltage signal U, the current signal I that will acquire respectively
Analysis, monitors the state of measurement, if measuring signal is out-of-limit, system early warning, and warning mark is shown in display screen.
(8) data disaply moudle: voltage signal U, current signal I after acquisition process, magnetic flux signal Phi can pass through
Data disaply moudle exports in real time.
(9) data memory module: the signal data after acquisition process is by column storage, including time Time, voltage U, electric current
I, magnetic flux Φ.
(10) communication module: this measuring device use three kinds of general interfaces, USB interface, LAN interface, RS232 interface,
It can be selected according to the actual situation in measurement.
(11) function resets module: every time before measurement, can click " clearing " button, measurement data is zeroed out school
Standard guarantees that the secondary measurement result is not influenced by a preceding measurement result.
The dc magnetization for measuring certain model 3kV transformer model using a kind of power transformer iron core magnetic characterization devices is special
Property, it mainly comprises the steps that
Step 1: test loop is built, according to Fig. 6 mode connecting test circuit, with constant-current supply to the high-pressure side of transformer
Apply exciting current Ik, Ik∈ [0A, 10A] is spaced the value of certain range setting exciting current, for example, k=1,2,
3 ... when .9, corresponding Ik={ 0,0.2A, 0.3A, 0.5A, 1.0A, 3A, 5A, 7A, 9A } applies to transformer motivate one by one
Electric current；
Step 2: clicking " test " button, start the data acquisition function of test macro.Acquire high voltage side of transformer, low pressure
The voltage waveform signal U of sideAX、Uax, acquire excitation current waveform signal IAX；
Step 3: the signal of acquisition is converted by enhanced processing and A/D, analog signal is transformed to digital signal, and will be electric
Pressure and current digital signal are transferred to central processing module, carry out the calculating analysis of data；
Step 4: " threshold value is out-of-limit " judgement, voltage signal U are transferred in central processing module, first progress " threshold value is out-of-limit "
Analysis, if the signal of acquisition exceeds threshold value (the voltage threshold U of defaultmax=500V, current threshold Imax=33A), then
System issues early warning, identifies display early warning on display screen, if returning again to step 5 without departing from the threshold value of default；
Step 5: automatic integration calculation processing, the voltage signal U collected are accumulated automatically in central processing module
Partite transport is calculated, and corresponding high-pressure side, low-pressure side magnetic flux Φ are obtainedAX、Φax, the formula of calculating is shown in formula (1)；Current signal I transmission
Into central processing module, data conversion calculation processing is carried out, obtains magnetic field strength H, the formula of calculating is shown in formula (2)；Magnetic flux
Signal obtains magnetic induction density B using data conversion treatment, and calculation formula is shown in formula (3)
Step 6: data save, and save function by data, treated data are saved as txt text；
Step 7: clicking " clearing " button, the data of the secondary measurement are subjected to operation and reset calibration (in calculation process mode
Logic zero clearing, delete operation is not carried out to the data that store in step 5), the measurement result for guaranteeing next time is not superimposed previous
The influence of secondary measurement result.It is re-execute the steps 1-7, works as k=9, IkWhen=9A, 8 are gone to step；
Step 8: data being obtained according to step 1-7, choose low-pressure side magnetic induction density Bax, magnetic field strength H, can draw out
The DC magnetization curve of the transformer model, as shown in Figure 4.
Step 9: clicking " preservation " button, save test data, then click " System menu ", " data export " is selected to press
Button exports to the data of preservation in USB flash device.
Step 10: shutdown test system disassembles test loop, terminates test.
Case three: the measurement of residual magnetism after DC resistance of power transformer test
Using a 3kV transformer model as measurement object, illustrate to carry out transformer dc using technical solution of the present invention
The process of measurement of residual magnetism after resistance test.
A kind of measurement of power transformer iron core magnetic characteristic and analytical equipment, include following functions module:
(1) voltage acquisition module: led to by being connected to the DC voltage of high-pressure side and low-pressure side in transformer model and acquiring
The voltage signal of road, acquisition high-pressure side and low-pressure side, after enhanced processing and A/D conversion, it is transferred in data display screen
Real-time display curve, and show corresponding virtual value respectively on data display screen.
(2) it current acquisition module: by the DC current acquisition channel being connected in transformer model high pressure side loop, adopts
Collect on high-tension side exciting current I signal, after enhanced processing and A/D conversion, is transferred to real-time display in data display screen
I-t curve, and corresponding virtual value is shown on data display screen.
(3) magnetic-flux measurement module: led to by being connected to the direct current flux of high-pressure side and low-pressure side in transformer model and acquiring
Road acquires the voltage signal U of high-pressure side and low-pressure sideAX、Uax, after enhanced processing and A/D conversion, it is transferred to central fortune
Control module is calculated, carries out signal integration processing (the base wavelet operation of real-time perfoming integrated signal in integral process), obtains height
Press the magnetic flux signal Phi of side and low-pressure sideAX、Φax, it is transferred to real-time display Φ-t curve in data display screen, and aobvious in data
Corresponding peak value is shown in display screen respectively.
(4) frequency generator module: frequency generator can manually set the frequency of sampling and the averagely counting of sampling, produce
The clock trigger signal of raw Five-channel sampling, realizes synchronized sampling.
(5) electrical isolation module: being converted by A/D, by the analog signal of high voltage, high current be converted to it is low level from
Dissipate digital signal, the safety in protection circuit.
(6) central processing module: the signal of each channel acquisition is transferred in central processing module, carries out further
Operational analysis, including voltage signal U automatic integration operation, the numerical value conversion of current signal I, the display control of touch screen, U-t,
Storage and export of display control, data that I-t, Φ-t draw etc..
(7) " threshold value is out-of-limit " comparison failure protection module: is carried out by voltage signal U, the current signal I that will acquire respectively
Analysis, monitors the state of measurement, if measuring signal is out-of-limit, system early warning, and warning mark is shown in display screen.
(8) data disaply moudle: voltage signal U, current signal I after acquisition process, magnetic flux signal Phi can pass through
Data disaply moudle exports in real time.
(9) data memory module: the signal data after acquisition process is by column storage, including time Time, voltage U, electric current
I, magnetic flux Φ.
(10) communication module: this measuring device use three kinds of general interfaces, USB interface, LAN interface, RS232 interface,
It can be selected according to the actual situation in measurement.
(11) function resets module: every time before measurement, can click " clearing " button, measurement data is zeroed out school
Standard guarantees that the secondary measurement result is not influenced by a preceding measurement result.
The D.C. resistance test of certain model 3kV transformer model is measured using a kind of power transformer iron core magnetic characterization devices
Remanent magnetism afterwards, mainly comprises the steps that
Step 1: building test loop, with the straight resistance of the high-pressure side winding of instrument for measuring DC resistance device test transformer, directly
The electric current gear of leakage resistance test equipment is selected as In, according to the straight resistance of the current sequence measuring transformer one by one of setting；Setting
Positive sequence be respectively [0.05A, 0.1A, 0.5A, 1A, 2A, 5A, 10A, 20A], the negative sense sequence set as [- 0.05A ,-
0.1A、-0.5A、-1A、-2A、-5A、-10A、-20A]。
Step 2: clicking " test " button, start the data acquisition function of test macro.Acquire the electricity of step down side
Corrugating signal Uax, acquire excitation current waveform signal I；
Step 3: the signal of acquisition is converted by enhanced processing and A/D, analog signal is transformed to digital signal, and will be electric
Pressure and current digital signal are transferred to central processing module, carry out the calculating analysis of data；
Step 4: " threshold value is out-of-limit " judgement, voltage signal U are transferred in central processing module, first progress " threshold value is out-of-limit "
Analysis, if the signal of acquisition exceeds threshold value (the voltage threshold U of defaultmax=500V, current threshold Imax=33A), then
System issues early warning, identifies display early warning on display screen, if returning again to step 5 without departing from the threshold value of default；
Step 5: automatic integration calculation processing, the voltage signal U collected are accumulated automatically in central processing module
Partite transport is calculated, and the corresponding magnetic flux Φ of low-pressure side is obtainedax, the formula of calculating is shown in formula (1)；Magnetic flux signal using data conversion at
Reason, obtains magnetic induction density B, calculation formula is shown in formula (3)；
Step 6: data save, and save function by data, treated data are saved as txt text；
Step 7: clicking " clearing " button, the data of the secondary measurement are subjected to operation and reset calibration (in calculation process mode
Logic zero clearing, delete operation is not carried out to the data that store in step 5), the measurement result for guaranteeing next time is not superimposed previous
The influence of secondary measurement result.It is re-execute the steps 1-7, works as k=8, Ik=20A or k=8, IkWhen=- 20A, 8 are gone to step；
Step 8: data being obtained according to step 1-7, choose transformer residual magnetic flux density Br, excitation current I, Ke Yihui
The straight resistance test remanent magnetism change curve of the transformer model is produced, as shown in Figure 5.
The application provides a kind of measurement of power transformer iron core magnetic characteristic and analysis method simultaneously, as shown in fig. 6, its feature
It is, comprising:
Step S601 acquires the voltage signal, current signal and magnetic flux signal of power transformer；And by the voltage
Signal, current signal and magnetic flux signal are transferred to frequency generator module；
The generation of the voltage signal, current signal and magnetic flux signal is synchronized and is adopted by step S602, frequency generator module
The pulse train of sample realizes synchronized sampling, and analog-signal transitions are digital signal after A/D is converted by the data after sampling,
The digital signal realizes electrical isolation by electrical isolation module；
Step S603, the digital data transmission to CPU module, CPU module believe the number
Voltage signal in number carries out the band modified automatic integration of baseline and magnetic flux signal is calculated, and carries out data conversion to current signal
Magnetic field strength is calculated, magnetic induction intensity is calculated by numerical value conversion to magnetic flux signal；
Step S604, the digital data transmission to failure protection module, according to preset signal measurement range
Max-thresholds carry out the out-of-limit judgement of threshold value.
The above embodiments are merely illustrative of the technical scheme of the present invention and are not intended to be limiting thereof, although referring to above-described embodiment pair
The present invention is described in detail, those of ordinary skill in the art still can to a specific embodiment of the invention into
Row modifies perhaps equivalent replacement and these exist without departing from any modification of spirit and scope of the invention or equivalent replacement
Apply within pending claims of the invention.
Claims (10)
1. a kind of power transformer iron core magnetic characteristic measurement and analytical equipment characterized by comprising
Voltage acquisition module, current acquisition module, magnetic flux acquisition module, frequency generator module, electrical isolation module, centre
Manage module and failure protection module；After device starting, channels of information acquisition acquires power transformer by voltage acquisition module
Voltage signal；The current signal of power transformer is acquired by current acquisition module；Electric power is acquired by magnetic flux acquisition module
The magnetic flux signal of transformer；Frequency generator module generates the pulse signal of synchronized sampling, feeds back to and adopt according to the signal of acquisition
Synchronized sampling is realized in sample channel, and analog-signal transitions are digital signal, pass through electricity by the data after sampling after A/D is converted
Gas isolation module realizes electrical isolation；Digital data transmission carries out band base wavelet into central processing module, to voltage signal
Automatic integration magnetic flux signal is calculated, to current signal carry out data conversion magnetic field strength is calculated, to magnetic flux signal
Magnetic induction intensity is calculated by numerical value conversion；Digital signal is transmitted to failure protection module, according to preset signal
The max-thresholds of measuring range carry out the out-of-limit judgement of threshold value.
2. the apparatus according to claim 1, which is characterized in that further include:
Data disaply moudle, for showing real-time voltage signal, current signal and magnetic flux signal by touching display screen
Waveform change curve can also show voltage signal, current signal magnetic field intensity signal magnetic flux signal, magnetic induction intensity signal
Virtual value；Touching display screen can to the range of voltage measurement, high-pressure side umber of turn, low-pressure side umber of turn, the length of magnetic path,
The parameters such as area of core section are configured.
3. the apparatus according to claim 1, which is characterized in that further include:
Data memory module, for saving the data of test and analysis, there are in the memory of system.
4. the apparatus according to claim 1, which is characterized in that further include:
Communication module realizes the control to test for the communication between PC machine measurement and analytical equipment by way of PC software
System；Also the export function that data may be implemented exports to the data of preservation in system memory in external storage equipment.
5. the apparatus according to claim 1, which is characterized in that further include:
Function resets module, for eliminating influence of the previous test data to test result next time.
6. the apparatus according to claim 1, which is characterized in that the digital signal is transmitted to failure protection module, according to
The max-thresholds of preset signal measurement range, after the step of carrying out threshold value out-of-limit judgement, further includes:
If out-of-limit, then system prompt early warning occurs, and show warning-sign on data disaply moudle by the out-of-limit judgement of threshold value
Know.
7. the apparatus according to claim 1, which is characterized in that described to carry out the band modified automatic product of baseline to voltage signal
Divide and magnetic flux signal, specific calculation formula be calculated are as follows:
In formula: ΦAX、Φax: the magnetic flux of high-pressure side winding, low-pressure side winding, unit are weber (Wb)；UAX、Uax: high-pressure side around
The voltage of group, low-pressure side winding, unit are volt (V)；T: sampling total time, unit are second (S).
8. the apparatus according to claim 1, which is characterized in that described that magnetic is calculated to current signal progress data conversion
Field intensity, specific calculation formula are as follows:
Wherein:
H: magnetic field strength when excitation, unit are amperes per meter (A/m)；
N1: the number of turns of high-pressure side winding, dimensionless；
IAX: the exciting current of high-pressure side winding, unit are ampere (A)；
Le: transformer equivalent magnetic circuit length, unit rice (m).
9. the apparatus according to claim 1, which is characterized in that described that magnetic is calculated by numerical value conversion to magnetic flux signal
Induction, specific calculation formula are as follows:
Wherein:
BAX、Bax: the magnetic induction intensity of high-pressure side winding, low-pressure side winding, unit are tesla (T)；
ΦAX、Φax: the magnetic flux of high-pressure side winding, low-pressure side winding, unit are weber (Wb)；
N1、N2: high-pressure side winding, low-pressure side umber of turn, dimensionless；
Ae: the equivalent cross-sectional area of iron core, unit are square metre (m2)。
10. a kind of power transformer iron core magnetic characteristic measurement and analysis method characterized by comprising
Acquire voltage signal, current signal and the magnetic flux signal of power transformer；And by the voltage signal, current signal,
And magnetic flux signal is transferred to frequency generator module；
Frequency generator module will generate the pulse of synchronized sampling according to the voltage signal, current signal and magnetic flux signal
Sequence realizes synchronized sampling, and analog-signal transitions are digital signal, the number after A/D is converted by the data after sampling
Signal realizes electrical isolation by electrical isolation module；
The digital data transmission is to CPU module, and CPU module is to the voltage signal in the digital signal
It carries out the band modified automatic integration of baseline and magnetic flux signal is calculated, it is strong that magnetic field is calculated to current signal progress data conversion
Degree, is calculated magnetic induction intensity by numerical value conversion to magnetic flux signal；
The digital data transmission is carried out to failure protection module according to the max-thresholds of preset signal measurement range
The out-of-limit judgement of threshold value.
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| CN112383309A (en) * | 2020-11-13 | 2021-02-19 | 广东澳鸿科技有限公司 | Analog-to-digital conversion circuit of magnetoelectric revolution speed sensor |
| CN114284999A (en) * | 2021-12-31 | 2022-04-05 | 杭州电力设备制造有限公司 | Transformer grouping switching-on device based on real-time magnetic flux error estimation |
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