CN108241099A - A kind of transformer DC magnetic bias status assessment and diagnostic method - Google Patents
A kind of transformer DC magnetic bias status assessment and diagnostic method Download PDFInfo
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- CN108241099A CN108241099A CN201611230215.8A CN201611230215A CN108241099A CN 108241099 A CN108241099 A CN 108241099A CN 201611230215 A CN201611230215 A CN 201611230215A CN 108241099 A CN108241099 A CN 108241099A
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- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
Abstract
The present invention provides a kind of transformer DC magnetic bias status assessment and diagnostic method, includes the following steps：After direct current invasion occurs for transformer, monitor the D.C. magnetic field intensity in the minds of transformer fe, the no-load current ratio of transformer under light condition, the DC current of winding neutral point, the vibration of transformer and noise, the Wen Sheng of transformer, transformer non-electricity protection act situation, high voltage side of transformer voltage waveform and current waveform, transformer oil chromatographic, and the device body appearance of transformer, if any one above-mentioned monitoring result does not meet preset condition, then judge that the direct current Invasive degree of transformer has influenced the normal operation of transformer, load or out of service should be reduced, otherwise, transformer continues to put into operation.The method of the invention can be assessed and be diagnosed to transformer DC magnetic bias state comprehensively, specifically.
Description
Technical field
The present invention relates to power transformer technical fields, and in particular to a kind of transformer DC magnetic bias status assessment and diagnosis
Method.
Background technology
Power transformer is very important equipment in electric system, and operating status directly influences the peace of electric system
Quan Xing.With putting into operation for electric system DC power transmission line, when monopole the earth is run, the power transformer near DC converter station
Device is invaded by DC current, causes vibration, noise and loss increases and problems of excessive heat, cause power transformer magnetic saturation, lead
Loss, temperature is caused to rise increase, and hot-spot may be caused, aggravation vibrations increase noise, and the harmonic wave generated can also cause system
Voltage waveform distortion and protective relaying maloperation work etc., so as to influence the safe operation of power transformer, this DC current intrusion
The phenomenon that power transformer, is referred to as D.C. magnetic biasing.With being continuously increased for China's super high voltage direct current electricity transmission line, power transformer
The DC magnetic bias phenomena of device becomes increasingly severe.
The data for having grid company shows that, when straight-flow system monopole the earth is run, neighbouring power transformer is in neutral point
During direct current intrusion 10A or so, the noise figure of 220kV power transformers reaches 84-90dB (A), than increasing 10- during normal operation
20dB(A).Meanwhile loss, Wen Sheng also correspondingly increase.This loss, Wen Sheng and noise increase phenomenon meeting serious threat to electricity
The safe operation of power transformer, therefore after transformer is invaded by direct current, transformer DC magnetic bias state is carried out assessment and
It is imperative to diagnose.However, the project plan comparison that transformer DC magnetic bias state is assessed and diagnosed in the prior art is single,
Lack comprehensive.
Invention content
The technical problems to be solved by the invention are for the drawbacks described above in the presence of the prior art, are provided a kind of complete
Face, specific transformer DC magnetic bias status assessment and diagnostic method.
Technical solution is used by solving present invention problem：
The present invention provides a kind of transformer DC magnetic bias status assessment and diagnostic method, includes the following steps：
After direct current invasion occurs for transformer, transformation under the D.C. magnetic field intensity, light condition in the minds of monitoring transformer fe
The no-load current of device is more non-than, the vibration of the DC current of winding neutral point, transformer and noise, the Wen Sheng of transformer, transformer
The device body of electric quantity protective action situation, high voltage side of transformer voltage waveform and current waveform, transformer oil chromatographic and transformer
Appearance, if any one above-mentioned monitoring result does not meet preset condition, judging the direct current Invasive degree of transformer has influenced
To the normal operation of transformer, load or out of service should be reduced, otherwise, transformer continues to put into operation.
Optionally, the D.C. magnetic field intensity is Hdc=NIPhase/ L, wherein, N is the number of turn of winding；If transformer is three-phase
Transformer, then IPhaseFor single-phase DC current value, if transformer is single-phase transformer, IPhaseFor each phase DC current values；L be with
The magnetic loop length that other column calculates.
Optionally, for the D.C. magnetic field intensity H in the minds of transformer fedcMonitoring result for, if HdcMore than 200A/
M, then the monitoring result do not meet preset condition, judge that the direct current Invasive degree of transformer has influenced the normal fortune of transformer
Row should reduce load or out of service.
Optionally, the no-load current ratio includes unloaded fundamental current than K1, unloaded second harmonic current than K2, zero load three
Subharmonic current than K3 and unloaded quintuple harmonics electric current ratio K5,
K1=I01d/I01
K2=I02d/I02
K3=I03d/I03
K5=I05d/I05
Wherein, I01d is the unloaded fundamental current value after direct current invasion, and I01 is unloaded fundamental current when not invading direct current
Value；I02d is the unloaded second harmonic current value after direct current invasion, and I02 is unloaded second harmonic current when not invading direct current
Value；I03d is the unloaded triple harmonic current value after direct current invasion, and I03 is unloaded triple harmonic current when not invading direct current
Value；I05d is the unloaded quintuple harmonics current value after direct current invasion；I05 is unloaded quintuple harmonics electric current when not invading direct current
Value.
Optionally, for the no-load current of transformer under light condition than monitoring result for, if unloaded fundamental current
Than K1, unloaded second harmonic current than K2, unloaded triple harmonic current than K3 and unloaded quintuple harmonics electric current than arbitrary in K5
One electric current ratio is more than 7, then the monitoring result does not meet preset condition, judges that the direct current Invasive degree of transformer has influenced
The normal operation of transformer should reduce load or out of service.
Optionally, for the monitoring result of the DC current of winding neutral point, if the DC current of winding neutral point
Value does not meet preset condition more than 12A, the then monitoring result, judges that the direct current Invasive degree of transformer has influenced transformer
Normal operation, should reduce load or it is out of service.
Optionally, for the monitoring result of the vibration of transformer, if oil tank of transformer wall vibrations incrementss are more than 50 μ
M, then the monitoring result do not meet preset condition, judge that the direct current Invasive degree of transformer has influenced the normal fortune of transformer
Row, should reduce load；For the monitoring result of the noise of transformer, if at the top of transformer oil tank wall or fuel tank internal iron core
Noise sound incrementss be more than 10dB (A), then the monitoring result do not meet preset condition, judge transformer direct current invasion
Degree has influenced the normal operation of transformer, should reduce load or out of service.
Optionally, for the monitoring result of the temperature of transformer, if oil tank of transformer wall temperature rises or top-oil temperature liter
Incrementss be more than that 10K or transformer top-oil temperature rise be more than 75K, then the monitoring result does not meet preset condition, judgement change
The direct current Invasive degree of depressor has influenced the normal operation of transformer, should reduce load or out of service.
Optionally, step is further included：
The electric property of transformer is rechecked, if the electric property of transformer is unqualified, judges the direct current invasion of transformer
Degree has influenced the normal operation of transformer, should reduce load, and otherwise, transformer continues to put into operation.
Optionally, the transformer is three-phase five-limb power transformer, single-phase four-column type power transformer or single-phase three
Pillar power transformer.
Advantageous effect：
Transformer DC magnetic bias status assessment and diagnostic method of the present invention, for the change for having carried out D.C. magnetic biasing experiment
Depressor and the transformer invaded by direct current in being currently running carry out electrical, machine performance analysis, to ensure transformer
Safety of the product in follow-up operation.
Description of the drawings
Fig. 1 is the flow chart of transformer DC magnetic bias status assessment provided in an embodiment of the present invention and diagnostic method；
Fig. 2A vibration signals at Typical Vibration measuring point when no direct current is invaded for transformer provided in an embodiment of the present invention
Time domain waveform and frequency spectrum profile；
Fig. 2 B Typical Vibrations after direct current (bias current 2A) occurs and invades for transformer provided in an embodiment of the present invention
The time domain waveform and frequency spectrum profile of vibration signal at measuring point；
Fig. 3 A noise signals at pink noise measuring point when no direct current is invaded for transformer provided in an embodiment of the present invention
Time domain waveform and frequency spectrum profile；
Fig. 3 B pink noises after direct current (bias current 2A) occurs and invades for transformer provided in an embodiment of the present invention
The time domain waveform and frequency spectrum profile of noise signal at measuring point；
Fig. 4 A are transformer provided in an embodiment of the present invention in the case where floating voltage is 1.0Un, bias current is 0A
Electric current and voltage oscillogram；
Fig. 4 B are transformer provided in an embodiment of the present invention in the case where floating voltage is 1.0Un, bias current is 2A
Electric current and voltage oscillogram；
Fig. 4 C are transformer provided in an embodiment of the present invention in the case where load voltage is 1.0Un, bias current is 2A
Electric current and voltage oscillogram；
Fig. 5 is the D.C. magnetic biasing status assessment of transformer provided in an embodiment of the present invention and diagnostics table exemplary plot.
Specific embodiment
For those skilled in the art is made to more fully understand technical scheme of the present invention, with reference to the accompanying drawings and examples to this
Invention is described in further detail.
Inventor has studied no-load current variation of the AC transformer under D.C. magnetic biasing state according to product testing early period
Feature, neutral point direct current and the relationship of transformer noise vibration incrementss, frequency of the vibration noise under D.C. magnetic biasing state
Spectrum feature and no-load loss changing rule, for be under D.C. magnetic biasing state transformer station high-voltage side bus when performance change make
Effectively analysis and judge, and have accumulated practical experience, so as to propose transformer DC magnetic bias status assessment of the present invention and
Diagnostic method provides reference for transformer safety operation.
Transformer DC magnetic bias status assessment and diagnostic method of the present invention are laggard in transformer generation direct current invasion
Capable, it is specifically as follows, is carried out, while need to be tried according to transformer DC magnetic bias after the experiment of transformer DC magnetic bias tolerance
Proved recipe law technology specification obtains related data；May be that when the transformer of operation is invaded by direct current or direct current is invaded
After carry out, while related data need to be obtained.
Above-mentioned related data includes the data that need to be monitored and transformer device structure parameter, wherein, the data that need to be monitored include：In
Property point invasion DC current, high side voltage waveform, no-load current waveform, no-load loss, load loss, transformer Wen Sheng, machine
Tool vibration, noise and oil chromatography etc.；Transformer device structure parameter includes：Transformer model, capacity, voltage class, the mode of connection (star
Shape wiring), iron core pattern, structural parameters (magnetic loop length), sectional dimension, umber of turn etc..It should be noted that only exist
During star connection neutral ground, just there is the earth direct current to enter transformer by neutral ground line, and other connection (such as triangles
Shape connection) without direct current access is invaded, therefore the mode of connection that the transformer in the present invention uses is star-star connection, hereafter no longer
It repeats.
Moreover, the present embodiment is suitable for three-phase five-limb power transformer, single-phase four-column type power transformer or single-phase three
Pillar power transformer, but it is not suitable for three-phase three-limb power transformer.This is because three-phase three-limb power transformer exists
In D.C. magnetic biasing experiment, due to three-phase dc magnetic flux same-phase, it is impossible to it is closed and is formed into a loop in iron core, it need to be in iron core outer space
Between be closed, there is no iron core saturation problem, thus test measurement to loss, noise, vibration and frequency spectrum rule be that noise slightly has
Increase, loss, exciting current variation unobvious, be totally different from the iron core of above-mentioned other structures power transformer, therefore this hair
The analysis and diagnosis that bright basis is electrical, the variation of mechanical quantity is carried out, is not suitable for three-phase three-limb power transformer.
Transformer DC magnetic bias status assessment and diagnostic method of the present invention is described in detail with reference to Fig. 1, it is specific to wrap
Include following steps S101-S112.
D.C. magnetic field intensity in the minds of step S101. monitoring transformer fes, if monitoring result does not meet the first preset condition,
Then judge that the direct current Invasive degree of transformer has influenced the normal operation of transformer, load or out of service should be reduced.
Specifically, the D.C. magnetic field intensity in the minds of transformer fe can be calculated by equation below：∮HdcL=NIPhase, then Hdc
=NIPhase/ L,
Wherein, HdcFor the D.C. magnetic field intensity (A/m) in iron core；N is the number of turn of winding；If transformer is three phase-change pressures
Device, then IPhaseFor single-phase DC current value (A), if transformer is single-phase transformer, IPhaseFor each phase DC current values (A)；L is
The magnetic loop length (m) calculated with other column.
In this step, if HdcMore than 200A/m, then it is assumed that HdcMonitoring result do not meet the first preset condition.At this point,
D.C. magnetic field intensity caused by invading direct current is larger, and the direct current Invasive degree of transformer has influenced the normal fortune of transformer
Row, should reduce load, when necessary can be out of service；Meanwhile transformer overall operation state need to be paid close attention to, such as monitoring vibration and
Noise level, tank surface and oil overhold layer Wen Sheng, oil chromatography etc..
The no-load current ratio of transformer under step S102. monitoring light conditions, if monitoring result does not meet the second default item
Part then judges that the direct current Invasive degree of transformer has influenced the normal operation of transformer, should reduce load or out of service.
Specifically, the no-load current ratio includes unloaded fundamental current than K1, unloaded second harmonic current than K2, zero load three
Subharmonic current than K3 and unloaded quintuple harmonics electric current ratio K5, and
K1=I01d/I01
K2=I02d/I02
K3=I03d/I03
K5=I05d/I05
Wherein, I01d is the unloaded fundamental current value after direct current invasion, and I01 is unloaded fundamental current when not invading direct current
Value；I02d is the unloaded second harmonic current value after direct current invasion, and I02 is unloaded second harmonic current when not invading direct current
Value；I03d is the unloaded triple harmonic current value after direct current invasion, and I03 is unloaded triple harmonic current when not invading direct current
Value；I05d is the unloaded quintuple harmonics current value after direct current invasion；I05 is unloaded quintuple harmonics electric current when not invading direct current
Value.Above-mentioned current value is obtained by monitoring no-load current waveform.
In this step, if unloaded fundamental current compares K3 than K1, unloaded second harmonic current than K2, unloaded triple harmonic current
Be more than 7 than any one electric current ratio in K5 with unloaded quintuple harmonics electric current, then it is assumed that the no-load current of transformer than prison
It surveys result and does not meet the second preset condition.At this point, the direct current Invasive degree of transformer has influenced the normal operation of transformer,
Load should be reduced, it when necessary can be out of service；Meanwhile transformer overall operation state need to be paid close attention to, such as monitoring vibration and made an uproar
Sound is horizontal, tank surface and oil overhold layer Wen Sheng, oil chromatography etc..
Step S103. monitors the DC current of winding neutral point, if monitoring result does not meet third preset condition, judges
The direct current Invasive degree of transformer has influenced the normal operation of transformer, should reduce load or out of service.
In this step, if the DC current values of winding neutral point are more than 12A, then it is assumed that the DC current of winding neutral point
Monitoring result do not meet third preset condition.At this point, the direct current Invasive degree of transformer has influenced the normal of transformer
Operation, should reduce load, when necessary can be out of service；Meanwhile transformer overall operation state, such as monitoring vibration need to be paid close attention to
With noise level, tank surface and oil overhold layer Wen Sheng, oil chromatography etc..
Step S104. monitors the vibration of transformer, if monitoring result does not meet the 4th preset condition, judges transformer
Direct current Invasive degree has influenced the normal operation of transformer, should reduce load or out of service.
In this step, change the D.C. magnetic biasing state for determining transformer according to the rumble spectrum of transformer, if transformer oil
Tank wall vibrates incrementss more than 50 μm, then it is assumed that does not meet the 4th preset condition to the monitoring result of the vibration of transformer.At this point,
The direct current Invasive degree of transformer has influenced the normal operation of transformer, should reduce load, when necessary can be out of service；Together
When, transformer overall operation state, such as monitoring noise level, tank surface and oil overhold layer Wen Sheng, oil chromatography need to be paid close attention to.
Typical Vibration measuring point need to be selected in the appropriate position on oil tank wall, transformer is when no direct current is invaded and transformer
The time domain waveform of vibration signal and frequency spectrum profile are divided at Typical Vibration measuring point after direct current (bias current 2A) occurs and invades
Not as shown in Figure 2 A and 2 B.
Step S105. monitors the noise of transformer, if monitoring result does not meet the 5th preset condition, judges transformer
Direct current Invasive degree has influenced the normal operation of transformer, should reduce load or out of service.
In this step, the D.C. magnetic biasing state of transformer is determined according to the noise sound of transformer, if oil tank of transformer
Noise sound incrementss at the top of wall or fuel tank internal iron core are more than 10dB (A), then it is assumed that the monitoring to the noise of transformer
As a result the 5th preset condition is not met.At this point, the direct current Invasive degree of transformer has influenced the normal operation of transformer, it should
Reduce load, it when necessary can be out of service；Meanwhile transformer overall operation state need to be paid close attention to, as monitoring vibration is horizontal, oil
Case surface and oil overhold layer Wen Sheng, oil chromatography etc..
Wherein, sound pressure level is represented with symbol SPL, is defined as acoustic pressure virtual value p (e) to be measured and reference sound pressure p (ref)
Ratio take common logarithm, multiplied by with 20, i.e.,：SPL=20log10[p (e)/p (ref)], unit are decibel (dB).Acoustic pressure is
For atmospheric pressure by the overbottom pressure of the variation generated after acoustic perturbation, as atmospheric pressure, it is equivalent to the superposition on atmospheric pressure
Pressure change caused by one acoustic perturbation.Sound level be similar to human ear to sound each frequency content level of sensitivity synthesis into total sound
It arbitrarily downgrades numerical value.It should be according to " the 10th part of GB1094.10 power transformers to the measurement of sound level：Sound level measures " it carries out.
In addition, it can also change the D.C. magnetic biasing shape for determining transformer according to the noise spectrum of the transformer under light condition
State.Specifically, when transformer is in light condition, the noise signal at pink noise measuring point is acquired, obtains the noise signal
Corresponding frequency spectrum, when occurring odd harmonic in noise spectrum, and content be more than default content (can by those skilled in the art according to
Actual conditions are set) when, it was demonstrated that harmonic content is more, and D.C. magnetic field intensity is higher caused by D.C. magnetic biasing, transformer
Direct current Invasive degree has influenced the normal operation of transformer, should reduce load, when necessary can be out of service；Meanwhile it needs close
Cut concern transformer overall operation state, such as monitoring vibration level, tank surface and oil overhold layer Wen Sheng, oil chromatography.
It need to select pink noise measuring point at the top of oil tank wall or fuel tank internal iron core, transformer is when no direct current is invaded and change
The time domain waveform and spectrum distribution of depressor noise signal at pink noise measuring point after direct current (bias current 2A) occurs and invades
Figure difference is as shown in Figure 3A and Figure 3B.
Step S106. monitors the Wen Sheng of transformer, if monitoring result does not meet the 6th preset condition, judges transformer
Direct current Invasive degree has influenced the normal operation of transformer, should reduce load or out of service.
In this step, if the incrementss that oil tank of transformer wall temperature rises or top-oil temperature rises are more than 10K or transformer top layer
Oil temperature is risen more than 75K, then it is assumed that does not meet the 6th preset condition to the monitoring result of the Wen Sheng of transformer.At this point, transformer
Direct current Invasive degree has influenced the normal operation of transformer, should reduce load, when necessary can be out of service；Meanwhile it needs close
Cut concern transformer overall operation state, such as monitoring vibration and noise level, oil chromatography.
Wherein, the temperature of oil tank wall is measured using the method for infrared thermal imaging.It should basis to the measurement of the Wen Sheng of transformer
" GB1094.2 power transformer part 2s：The Wen Sheng " of liquid soaking transformer is carried out.
Step S107. monitors transformer non-electricity protection act situation, if monitoring result does not meet the 7th preset condition,
The direct current Invasive degree of judgement transformer has influenced the normal operation of transformer, should reduce load or out of service.
In this step, if the situation of transformer non-electricity protection act is has acted, then it is assumed that monitoring result does not meet the
Seven preset conditions.At this point, the direct current Invasive degree of transformer has influenced the normal operation of transformer, load should be reduced, it must
It can be out of service when wanting；Meanwhile transformer overall operation state need to be paid close attention to, such as monitoring vibration and noise level, gas tank gage
Face and oil overhold layer Wen Sheng, oil chromatography etc..
Wherein, non-ionizing energy loss refers to the fault actions reflected by non-electric quantity or the protection transmitted, generally refers to protect
The criterion of shield is not electricity, but non electrical quantity.In the present embodiment, non-ionizing energy loss action can be pressure relief valve, gas after
The actuation of an alarm of electric appliance.Certainly, non-ionizing energy loss should not malfunction.
Step S108. monitors high voltage side of transformer voltage waveform and current waveform, is preset if monitoring result does not meet the 8th
Condition then judges that the direct current Invasive degree of transformer has influenced the normal operation of transformer, should reduce load or exit fortune
Row.
In this step, if compared with when D.C. magnetic biasing does not occur, in high voltage side of transformer electricity unloaded, under load condition
Corrugating or current waveform distort, and distortion degree (can be by those skilled in the art according to practical feelings more than predeterminable level
Condition is set), then it is assumed that the 8th default article is not met to the monitoring result of high voltage side of transformer voltage waveform or current waveform
Part, the direct current Invasive degree of transformer have influenced the normal operation of transformer, should reduce load, can exit fortune when necessary
Row；Meanwhile transformer overall operation state need to be paid close attention to, such as monitoring vibration level, tank surface and oil overhold layer Wen Sheng, oil colours
Spectrum etc..
Transformer is in the case where floating voltage is 1.0Un, bias current is 0A, floating voltage 1.0Un, bias current
Electric current and voltage oscillogram in the case of for 2A and in the case that load voltage is 1.0Un, bias current is 2A are respectively such as
Shown in Fig. 4 A, Fig. 4 B and Fig. 4 C.
Step S109. monitors transformer oil chromatographic, if monitoring result does not meet the 9th preset condition, judges transformer
Direct current Invasive degree has influenced the normal operation of transformer, should reduce load or out of service.
In this step, if compared with when D.C. magnetic biasing does not occur, transformer oil chromatographic occurs abnormal, then it is assumed that transformer
The monitoring result of oil chromatography does not meet the 9th preset condition, and the direct current Invasive degree of transformer has influenced the normal of transformer
Operation, should reduce load, when necessary can be out of service；Meanwhile transformer overall operation state, such as monitoring vibration need to be paid close attention to
With noise level, tank surface and oil overhold layer temperature rise etc..It should be according to " solution gas in GB7252 transformer oil to the measurement of oil chromatography
Directive/guide is analyzed and judged to body " it carries out.
Wherein, it is more than pre- bidding that the abnormal gas component content referred in transformer oil sample, which occurs, in transformer oil chromatographic
Accurate (being set by those skilled in the art according to actual conditions).The gas component includes H2、CO、CO2、CH4、C2H6、
C2H4、C3H8、C2H2、C3H6、C1+C2。
Step S110. monitors the device body appearance of transformer, if monitoring result does not meet the tenth preset condition, judges transformation
The direct current Invasive degree of device has influenced the normal operation of transformer, should reduce load or out of service.
In this step, if there is exception in one of the iron core of transformer, coil and lead, then it is assumed that transformer body appearance
Monitoring result do not meet the tenth preset condition, the direct current Invasive degree of transformer has influenced the normal operation of transformer,
Load should be reduced, it when necessary can be out of service；Meanwhile transformer overall operation state need to be paid close attention to, such as monitoring vibration and made an uproar
Sound level, tank surface and oil overhold layer temperature liter etc..
Since D.C. magnetic biasing can cause iron coring vibration to increase, device body positioning and fixing structure part need to be checked accordingly,
If exception occurs in iron core, for example, iron core loosens, its consolidation process that carries out large repairs is coped with, in another example, on the inside of iron core corner window
Surface is defective, should be repaired or be replaced.If exception occurs in coil, for example, coil loosens, reply coil takes compression
Measure.If exception occurs in lead, for example, lead loosens, cope with lead and its clamping framework uses necessary security measure.
If the monitoring result in step S111. steps S101-S110 meets preset condition, transformer state is good,
It can continue to put into operation.
Step S112. rechecks the electric property of transformer, if the electric property of transformer is unqualified, judges transformer
Direct current Invasive degree has influenced the normal operation of transformer, should reduce load, and otherwise, transformer continues to put into operation.Wherein, become
Whether the electric property of depressor is qualified can be combined reality by those skilled in the art according to detected value with the comparison situation of factory-said value
Situation judges.
In this step, if the time of direct current invasion is longer and/or the DC current of invasion is larger, need to recheck transformer
Electric property.The electrical performance test re-started is needed to include：Insulation Test, low-voltage test, no-load loss experiment and sky
Carry exciting current experiment.Wherein, Insulation Test includes insulation resistance, winding D.C. resistance, the winding frequency that can carry out at the scene
Ring curve, the experiment of low-voltage short-circuit impedance, insulation oil test drawn game portion discharge test.If no-load loss increases before and after reinspection experiment
The percentage of amount is more than 4%, then it is assumed that no-load loss experiment is unqualified.If open-circuit excitation electric current incrementss before and after reinspection experiment
Percentage is more than 30%, then it is assumed that open-circuit excitation current testing is unqualified.
The situation example that the D.C. magnetic biasing state of transformer is assessed and diagnosed by above-mentioned steps S101-S112 is such as
Shown in Fig. 5.
In conclusion transformer DC magnetic bias status assessment and diagnostic method described in the present embodiment, for having carried out direct current
The transformer of magnetic bias experiment and transformer invade by direct current in being currently running, carry out electrically, the analysis of machine performance,
To ensure safety of the power transformer product in follow-up operation.
It is understood that the principle that embodiment of above is intended to be merely illustrative of the present and the exemplary implementation that uses
Mode, however the present invention is not limited thereto.For those skilled in the art, in the essence for not departing from the present invention
In the case of refreshing and essence, various changes and modifications can be made therein, these variations and modifications are also considered as protection scope of the present invention.
Claims (10)
1. a kind of transformer DC magnetic bias status assessment and diagnostic method, which is characterized in that include the following steps：
After direct current invasion occurs for transformer, transformer under the D.C. magnetic field intensity, light condition in the minds of monitoring transformer fe
No-load current is than, the vibration of the DC current of winding neutral point, transformer and noise, the Wen Sheng of transformer, transformer non-electricity
Outside the device body of protection act situation, high voltage side of transformer voltage waveform and current waveform, transformer oil chromatographic and transformer
It sees, if any one above-mentioned monitoring result does not meet preset condition, judges that the direct current Invasive degree of transformer has influenced
The normal operation of transformer should reduce load or out of service, and otherwise, transformer continues to put into operation.
2. according to the method described in claim 1, it is characterized in that, the D.C. magnetic field intensity is Hdc=NIPhase/ L, wherein, N is
The number of turn of winding；If transformer is three-phase transformer, IPhaseFor single-phase DC current value, if transformer is single-phase transformer,
IPhaseFor each phase DC current values；L is the magnetic loop length calculated with other column.
3. according to the method described in claim 2, it is characterized in that, for the D.C. magnetic field intensity H in the minds of transformer fedcPrison
It surveys for result, if HdcMore than 200A/m, then the monitoring result does not meet preset condition, judges the direct current Invasive degree of transformer
The normal operation of transformer has been influenced, load or out of service should be reduced.
4. according to the method described in claim 1, it is characterized in that, no-load current ratio include unloaded fundamental current than K1,
Unloaded second harmonic current than K2, unloaded triple harmonic current than K3 and unloaded quintuple harmonics electric current ratio K5,
K1=I01d/I01
K2=I02d/I02
K3=I03d/I03
K5=I05d/I05
Wherein, I01d is the unloaded fundamental current value after direct current invasion, and I01 is unloaded fundamental current value when not invading direct current；
I02d is the unloaded second harmonic current value after direct current invasion, and I02 is unloaded second harmonic current value when not invading direct current；
I03d is the unloaded triple harmonic current value after direct current invasion, and I03 is unloaded triple harmonic current value when not invading direct current；
I05d is the unloaded quintuple harmonics current value after direct current invasion；I05 is unloaded quintuple harmonics current value when not invading direct current.
5. according to the method described in claim 4, it is characterized in that, for transformer under light condition no-load current than prison
Survey for result, if unloaded fundamental current than K1, unloaded second harmonic current than K2, unloaded triple harmonic current than K3 and zero load
Quintuple harmonics electric current is more than 7 than any one electric current ratio in K5, then the monitoring result does not meet preset condition, judges transformer
Direct current Invasive degree influenced the normal operation of transformer, load or out of service should be reduced.
6. according to the method described in claim 1, it is characterized in that, for the DC current of winding neutral point monitoring result and
Speech, if the DC current values of winding neutral point are more than 12A, which does not meet preset condition, judges the straight of transformer
Stream Invasive degree has influenced the normal operation of transformer, should reduce load or out of service.
7. according to the method described in claim 1, it is characterized in that, for the monitoring result of the vibration of transformer, if becoming
Depressor fuel tank wall vibrations incrementss are more than 50 μm, then the monitoring result does not meet preset condition, judge the direct current invasion of transformer
Degree has influenced the normal operation of transformer, should reduce load；For the monitoring result of the noise of transformer, if becoming
Noise sound incrementss at the top of depressor oil tank wall or fuel tank internal iron core are more than 10dB (A), then the monitoring result is not met
Preset condition judges that the direct current Invasive degree of transformer has influenced the normal operation of transformer, should reduce load or exit
Operation.
8. according to the method described in claim 1, it is characterized in that, for the monitoring result of the temperature of transformer, if becoming
The incrementss that depressor fuel tank wall temperature rises or top-oil temperature rises are more than that 10K or transformer top-oil temperature are risen more than 75K, then the prison
It surveys result and does not meet preset condition, judge that the direct current Invasive degree of transformer has influenced the normal operation of transformer, should subtract
Small load or out of service.
9. according to the method described in any one of claim 1-8, which is characterized in that further include step：
The electric property of transformer is rechecked, if the electric property of transformer is unqualified, judges the direct current Invasive degree of transformer
The normal operation of transformer has been influenced, load should be reduced, otherwise, transformer continues to put into operation.
10. according to the method described in any one of claim 1-8, which is characterized in that the transformer is three-phase five-limb electricity
Power transformer, single-phase four-column type power transformer or single-phase three pillar type power transformer.
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| CN110687381A (en) * | 2019-10-24 | 2020-01-14 | 苏州宝应隆电机制造有限公司 | Method for evaluating direct-current magnetic bias state of transformer |
| CN111337782A (en) * | 2020-04-03 | 2020-06-26 | 苏州华电电气股份有限公司 | Main transformer bias live monitoring system |
| CN114019286A (en) * | 2021-11-05 | 2022-02-08 | 国网四川省电力公司经济技术研究院 | Transformer direct-current magnetic bias tolerance checking field test method and system |
| CN115186721A (en) * | 2022-09-13 | 2022-10-14 | 国网江西省电力有限公司电力科学研究院 | IMF-based dynamic calculation method for DC magnetic bias cumulative effect of transformer |
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| CN114019286B (en) * | 2021-11-05 | 2024-04-26 | 国网四川省电力公司经济技术研究院 | Transformer direct-current magnetic bias tolerance capability checking field test method and system |
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