CN103529350A - Method and device for detecting turn-to-turn short-circuit fault of high-power transformer - Google Patents

Abstract

The invention discloses a method and device for detecting a turn-to-turn short-circuit fault of a high-power transformer. The method comprises the following steps: creating a transformer winding and a detection system model of the transformer winding according to a structure adopted by the transformer winding, calculating transfer functions of a system in fault and normal states, judging the type of a turn-to-turn short circuit by calculating a standardized difference area value of the transfer functions in the fault and normal states, drawing a frequency deviation index curve chart, and uniquely determining the position of the transformer fault according to proportional positions of asymmetric points in the winding in the chart. According to the method, the type and the position of the turn-to-turn short-circuit fault of the high-capacity transformer are detected by the transfer functions; compared with the prior art, the judgment accuracy of the turn-to-turn short-circuit fault of the high-capacity transformer is improved, the probability and the risk of the similar faults of the high-capacity transformer are reduced, the running reliability of the high-capacity transformer is improved, the cost performance is good, and the operation is convenient.

Description

A kind of detection method of high-power transformer shorted-turn fault and device

Technical field

The present invention relates to the detection of transformer fault, especially relate to a kind of detection method and device of high-power transformer shorted-turn fault.

Background technology

In transformer, winding be most important, the most complicated be also the parts that the most easily break down.The fault of Transformer Winding mainly contains distortion, shelf depreciation and the turn-to-turn short circuit etc. of winding.Statistical data shows: Transformer Winding turn-to-turn short circuit accounts for 50%～60% of the medium-and-large-sized transformer fault of electric system.High-power transformer particularly, destroyed once break down, operation for whole electric system will affect greatly, cause serious economic loss, the winding of high-power transformer often adopts disc type winding simultaneously, every dish is comprised of some circle coils, and the detection of this turn-to-turn short circuit has brought larger difficulty.

At present, conventional several rate Transformer Winding turn-to-turn short circuit detection methods are as follows:

(1) stray field method

With the transformer that high-low pressure winding is contour, analyze, its under normal circumstances the magnetic line of force be evenly distributed, the winding middle part horizontal stray field component of section is zero.When transformer generation turn-to-turn short circuit, its Magnetic fluxleakage distribution will change.Now the magnetic line of force distributes and becomes very inhomogeneous, and section horizontal stray field component in middle part is no longer also zero.According to this principle, at winding middle part section, the variation that one Hall element is monitored stray field is installed, thus just can be simply and effectively judge transformer whether shorted-turn fault has occurred.But this method is the transformer through manufacturing for oneself, unified installation Hall element is unpractical therein, do not reach good overall economic efficiency, and be subject to the impact of the factors such as transformer electromagnetic interference (EMI), the accuracy of measurement of Hall element does not have a good guarantee yet.

(2) electric current and voltage compares method

Under transformer normal condition, no matter from high-pressure side pressurization or from low-pressure side pressurization, the no-load voltage ratio of surveying all equates, irrelevant with pressure side.When transformer generation shorted-turn fault, by same procedure, carry out same measurement, the no-load voltage ratio of surveying different and different with pressure side.Researchist draws by simulated experiment, and when high-pressure side exists 5% turn-to-turn short circuit, from high-pressure side pressurization, institute's no-load voltage ratio of surveying is poor in 1% error range of permission; From low-pressure side pressurization, the ratio error of surveying up to more than 30%.By simulated experiment, can show that the conclusion of judgement transformer shorted-turn fault is:

High-pressure side pressurization, voltage ratio changes not obvious, low-pressure side pressurization, voltage ratio significantly reduces, and fault is in high-pressure side;

Low-pressure side pressurization, voltage ratio changes not obvious, high-pressure side pressurization, voltage ratio enlarges markedly, and fault is in low-pressure side;

Low-pressure side pressurization, current ratio changes not obvious, high-pressure side pressurization, current ratio significantly reduces, and fault is in high-pressure side;

High-pressure side pressurization, current ratio changes not obvious, low-pressure side pressurization, current ratio enlarges markedly, and fault is in low-pressure side;

But although the method precision easy and simple to handle is limited.

(3) power attenuation method

After transformer generation shorted-turn fault, its inner winding Magnetic fluxleakage distribution can change, and the variation of stray field will directly have influence on the variation of added losses.As shorted-turn fault has occurred certain winding, the added losses of this winding will increase by a relatively large margin, and the added losses of other winding also can increase to some extent.Therefore, the characteristic quantity using power attenuation as monitoring transformer shorted-turn fault can be proposed.By the online acquisition to transformer both sides three-phase voltage current, the difference of calculating input-output power is power attenuation, and then judge whether transformer the order of severity of shorted-turn fault and fault has occurred, can also judge which phase winding fault has occurred, thereby realize the detection to transformer shorted-turn fault simultaneously.

Though power attenuation method monitoring transformer shorted-turn fault principle is clear, when utilizing power attenuation method judgement shorted-turn fault, often to be equipped with other monitoring means at present, as Oil chromatography analysis, by comprehensive judgement to the result whether being out of order.Therefore this detection method complex operation and cannot implementing separately.

Summary of the invention

For solving the problem of above-mentioned existence of the prior art, the object of the present invention is to provide a kind of detection method and device with the high-power transformer shorted-turn fault of higher judgment accuracy and reliability, the method improves the accuracy of high-power transformer shorted-turn fault judgement, reduce probability and risk that the similar fault of high-power transformer occurs, improve high-power transformer reliability of operation.

For achieving the above object, technical scheme of the present invention is:

A detection method for high-power transformer shorted-turn fault, comprises the steps:

S1: the structure adopting according to Transformer Winding, set up Transformer Winding and detection system model thereof;

S2: obtain respectively the transport function under the fault two states of intact He Za road, circle road according to Transformer Winding and detection system model thereof;

S3: calculate the standardization difference area of transport function under the fault two states of intact He Za road, described circle road, and judge the type of turn-to-turn short circuit according to standardization difference area value;

Standardization difference area SDA value is not equal to a zero indication transformer winding generation single turn short circuit, wherein, when being more than or equal to threshold value, standardization difference area SDA value represents to have occurred short circuit between dish, when SDA value is greater than zero and represents to have occurred single turn short circuit while being less than threshold value;

Area under the fault two states of intact He Za road, described standardization difference area Wei Za road under transfer curve poor;

S4: utilize frequency departure index to determine location of fault: first, draw frequency departure index curve diagram, then the proportional positions in winding is determined transformer fault position according to asymmetric point in figure.

Further, detection method according to claim 1, is characterized in that, described transport function is curtage transport function, and the computing formula of described electric current and voltage transfering function is respectively:

with

Wherein, TF _crepresent current transfer function, TF _vrepresent voltage transfering function, V _hthe input voltage that represents winding top terminal, I _earthand V _othe output current and the output voltage that are illustrated respectively in winding bottom terminals, w represents the frequency of input signal.

Further, the computing formula of described step S3 Plays difference area is as follows:

$\mathrm{SDA}=\frac{{\∫}_{f_{\min }}^{f_{\max }}|{\mathrm{TF}}_{\mathrm{Test}}\left(f\right)-{\mathrm{TF}}_{\mathrm{Ref}}\left(f\right)|\mathrm{df}}{{\∫}_{f_{\min }}^{f_{\max }}{\mathrm{TF}}_{\mathrm{Ref}}\left(f\right)}$

Wherein, SDA is required standardization difference area, and fmin and fmax are respectively frequency domain minimum value and maximal value, TF _testfor the transport function under the malfunction of reality test Za road, TF _reftransport function under the intact state that do not break down in Wei Za road.

Further, the frequency w of input signal described in step S2 gets 100kHz, 1MHz and 100Hz to the arbitrary numerical value between 1MHz.

Further, input voltage V described in step S2 _hfor sinusoidal voltage, amplitude is automatically adjusted between 100 and 240 volts.

Wherein, described step S4 specifically comprises:

S41: fixing input end is arranged on through step S3 and has determined bottom terminals or the top terminal of the Transformer Winding of fault type, output terminal be take input end and to the winding other end, is moved as starting point, is repeatedly sampling and record the resonance frequency under corresponding surveyed winding length in input end different distance;

S42: calculate the frequency departure index in different distance, formula is as follows:

${\mathrm{IFD}}_i=\frac{{\mathrm{\Δf}}_i}{f_{o,i}}\×100\%=\left(\frac{f_{k,i}-f_{o,i}}{f_{o,i}}\right)\×100\%$

Wherein, IFD _irepresent frequency departure index, f _k,iand f _o,ii resonance frequency while representing respectively intact not the breaking down in malfunction Xia Heza road, circle road, subscript k is used for representing circle road malfunction, subscript o is used for representing the intact state that do not break down in circle road;

S43: the number percent and the IFD that account for respectively whole winding lengths with the winding length of tested use _ivalue for transverse and longitudinal coordinate, is drawn frequency departure index IFDi value curve map, take to pass through that tested winding length accounts for whole winding lengths 50% place and be axis Z perpendicular to the straight line of transverse axis, and IFDi value curve is divided into curve A and curve B;

S44: curve B be take to axis Z and obtain its rotational symmetry curve C as axle, curve C and curve A are compared, obtain at ordinate value upper curve C and be greater than the part curve D that curve A or curve A are greater than curve C, according to the ordinate of curve D, be the proportional positions of asymmetric point in winding, determine transformer winding fault position.

Another object of the present invention is also to provide a kind of pick-up unit of the high-power transformer shorted-turn fault based on transport function, comprising:

System modeling module, for the structure adopting according to the winding of transformer, sets up Transformer Winding and detection system model;

Transport function detection module, obtains respectively the transport function under the intact two states in fault He Za road, circle road for Transformer Winding and the detection system model of setting up according to modeling detection module;

Fault type judge module, for calculating the standardization difference area of transport function under the intact two states in fault He Za road, described circle road, area under the intact two states in fault He Za road, described standardization difference area Wei Za road under transfer curve poor, judges the type of turn-to-turn short circuit according to standardization difference area value:

Standardization difference area SDA value is not equal to a zero indication transformer winding generation single turn short circuit, wherein when being more than or equal to threshold value, standardization difference area SDA value represents to have occurred short circuit between dish, when SDA value is greater than zero and represents to have occurred single turn short circuit while being less than threshold value;

Abort situation judge module, for utilizing frequency departure index to determine location of fault: draw frequency departure index curve diagram, the proportional positions according to asymmetric point in figure in winding can unique definite transformer fault position.

Wherein, described abort situation judge module specifically for:

Fixing input end is arranged on through step S3 and has determined bottom terminals or the top terminal of the Transformer Winding of fault type, output terminal be take input end and to the winding other end, is moved as starting point, is repeatedly sampling and record the resonance frequency under corresponding surveyed winding length in input end different distance;

Calculate the frequency departure index in different distance, formula is as follows:

${\mathrm{IFD}}_i=\frac{{\mathrm{\Δf}}_i}{f_{o,i}}\×100\%=\left(\frac{f_{k,i}-f_{o,i}}{f_{o,i}}\right)\×100\%$

Wherein, IFD _irepresent frequency departure index, f _k,iand f _o,ii resonance frequency while representing respectively intact not the breaking down in malfunction Xia Heza road, circle road, subscript k is used for representing circle road malfunction, subscript o is used for representing the intact state that do not break down in circle road;

With the winding length of tested use, account for respectively number percent and the IFD of whole winding lengths _ivalue for transverse and longitudinal coordinate, is drawn frequency departure index IFDi value curve map, take to pass through that tested winding length accounts for whole winding lengths 50% place and be axis Z perpendicular to the straight line of transverse axis, and IFDi value curve is divided into curve A and curve B;

Curve B be take to axis Z and obtain its rotational symmetry curve C as axle, curve C and curve A are compared, obtain at ordinate value upper curve C and be greater than the part curve D that curve A or curve A are greater than curve C, according to the ordinate of curve D, be the proportional positions of asymmetric point in winding, determine transformer winding fault position.

The present invention is based on the detection method of high-power transformer shorted-turn fault of transport function and the beneficial effect that device is obtained: the present invention utilizes transport function to detect the type of high-power transformer shorted-turn fault and position, compared with prior art, improved the accuracy of high-power transformer shorted-turn fault judgement, reduce probability and risk that the similar fault of high-power transformer occurs, improve high-power transformer reliability of operation, there is good cost performance and simple operation simultaneously.

Accompanying drawing explanation

Fig. 1 is the method flow diagram of the embodiment of the present invention.

Fig. 2 is the detection system model structure figure of the embodiment of the present invention.

Fig. 3 is the standardization difference area SDA schematic diagram of the embodiment of the present invention.

Fig. 4 is the frequency departure index IFDi curve map of the embodiment of the present invention.

Fig. 5 is another frequency departure index IFDi curve map of the embodiment of the present invention.

Embodiment

In order to make object of the present invention, technical scheme and advantage clearer, below in conjunction with drawings and Examples, the present invention is further elaborated.Should be appreciated that specific embodiment described herein, only in order to explain the present invention, is not intended to limit the present invention.

Next by specific embodiment, introduce for example concrete technical scheme of the present invention, following embodiment selects current transfer function to carry out the detection of shorted-turn fault.

The winding of high-power transformer often adopts disc type winding, and every dish is comprised of some circle coils, as 86 dishes, and the 400kV transformer of every dish 9 circles, following examples also be take disc type winding transformer and are described in detail as example.

Detection method and the device of a kind of high-power transformer shorted-turn fault of the present invention, comprise the steps:

S1: the structure adopting according to the winding of transformer, set up Transformer Winding and detection system model;

As shown in Figure 2, in model, Vi represents the input voltage of winding top terminal, V _obe illustrated in the output voltage of winding bottom terminals, utilize frequency response analyzer voltage to be carried out to the measurement of frequency domain.In this embodiment, in order to measure current signal, between bottom terminals and ground, connect the small resistor that a resistance equals 0.1 Europe, measure its voltage drop, then divided by resistance value, just can obtain I _earth.In the present embodiment, all frequency domain measurement frequency of utilization response analyzer Bode100 carry out, and frequency range is from 10Hz to 40MHz.Bode100 is with Direct Digital synthesized source, and amplitude and frequency are adjustable, for exciting testing apparatus, and with two receivers, for receiving and process input and output signal.Input sinusoidal voltage amplitude 100 and 240V between automatically adjust so that the minimum in output signal.In frequency domain measurement, input signal is the sine wave with variable frequency.For each frequency, the size of transport function equals the amplitude of output signal divided by the amplitude of input signal.The frequency of conversion input signal, can measure transport function at different frequency.

S2: wherein the computing formula of current transfer function is as follows to test respectively according to Transformer Winding and detection system model the current transfer function that obtains under the intact two states in fault He Za road, circle road:

${\mathrm{TF}}_C=\frac{\left|I_{\mathrm{Earth}}\left(\mathrm{j\ω}\right)\right|}{\left|V_H\left(\mathrm{j\ω}\right)\right|}$

Wherein, TF _crepresent current transfer function, TF _vrepresent voltage transfering function, V _hthe input voltage that represents winding top terminal, I _earthand V _obe illustrated respectively in output current and the output voltage of winding bottom terminals.

S3: the standardization difference area that calculates current transfer function under the intact two states in fault He Za road, described circle road, under the intact two states in fault He Za road, described standardization difference area Wei Za road, current transfer function area under a curve is poor, according to standardization difference area value, judge the type of turn-to-turn short circuit, concrete formula is as follows:

$\mathrm{SDA}=\frac{{\∫}_{f_{\min }}^{f_{\max }}|{\mathrm{TF}}_{\mathrm{Test}}\left(f\right)-{\mathrm{TF}}_{\mathrm{Ref}}\left(f\right)|\mathrm{df}}{{\∫}_{f_{\min }}^{f_{\max }}{\mathrm{TF}}_{\mathrm{Ref}}\left(f\right)}$

Wherein, SDA is required standardization difference area, and fmin and fmax are respectively frequency domain minimum value and maximal value, and TFTest is the transport function under the malfunction of actual test Za road, the reference transfer function under the intact state that do not break down in TFRef Wei Za road; In this embodiment, transformer coil is designed to tray type structure, and each coil panel has one to close on electric capacity over the ground and to other phase, other electric pressure coil, and coil self also has inductance.When frequency is lower than 100kHz with while surpassing 1MHz, test result is insensitive to the variation of inductance and electric capacity, and with the raising of showing frequency, the stray capacitance of test loop (lead-in wire) also can cause obvious impact to test result, so frequency range is selected 100kHz～1MHz.TFTest is the transport function under the malfunction of actual test Za road, reference transfer function under the intact state that do not break down in TFRef Wei Za road, standardization difference area SDA value is not equal to a zero indication transformer winding generation turn-to-turn short circuit, if single turn short circuit, what affect is the output current of a certain dish, and dish between Effect of Short Circuit be the output current of two dishes, to transport function TFTest, the value of single turn short circuit is more approaching with the value not breaking down, test result as shown in Figure 3, predetermined threshold value can be taken at 0.2 left and right, when surpassing threshold value 0.2, standardization difference area SDA value represents to have occurred short circuit between dish, when SDA value is greater than zero and represent to have occurred single turn short circuit while being less than threshold value 0.2, wherein predetermined threshold value is got different values according to the difference of concrete detection model.

S4: the resonance frequency deviation during by intact not the breaking down in actual test malfunction He Za road, Za road is carried out the judgement of abort situation, specifically comprises:

S41: fixing input end is arranged on through step S3 and has determined bottom terminals or the top terminal of the Transformer Winding of fault type, output terminal be take input end and to the winding other end, is moved as starting point, is repeatedly sampling and record the resonance frequency under corresponding surveyed winding length in input end different distance;

S42: calculate the frequency departure index in different distance, formula is as follows:

${\mathrm{IFD}}_i=\frac{{\mathrm{\Δf}}_i}{f_{o,i}}\×100\%=\left(\frac{f_{k,i}-f_{o,i}}{f_{o,i}}\right)\×100\%$

Wherein, IFD _irepresent frequency departure index, f _k,iand f _o,ii resonance frequency while representing respectively intact not the breaking down in malfunction Xia Heza road, circle road, subscript k is used for representing circle road malfunction, subscript o is used for representing the intact state that do not break down in circle road; Between from 100kHz to 1MHz, the resonance frequency that transformer occurs in whole transport functions in diverse location short circuit or even while not breaking down sees the following form:

Resonance frequency numbering (i)	Resonance value (f o,i）（kHz）
		1	27.4
2	43.3
		3	56.4
4	70.4
		5	82.6
6	93.8
		7	105
8	115
		9	126
10	137
		11	146
12	155
		13	762
14	791
		15	819
16	850
		17	879
18	907
		19	937
20	967

At step S3, determined that turn-to-turn short circuit is between single turn short circuit or dish short circuit in the situation that, according to the feature of transformer device structure symmetry, its resonance frequency also presents symmetry, center with respect to winding, transformer frequencies deviation also has symmetry, in transformer operational process, the exemplary frequency deviation values of abort situation can exceed certain numerical value, the size of numerical value and f _o,irelevant, utilize frequency departure index IFDi can determine location of fault, when frequency departure index IFDi presents can unique definite transformer fault position when asymmetric.

S43: the number percent and the IFD that account for respectively whole winding lengths with the winding length of tested use _ivalue for transverse and longitudinal coordinate, is drawn frequency departure index IFDi value curve map, take to pass through that tested winding length accounts for whole winding lengths 50% place and be axis Z perpendicular to the straight line of transverse axis, and IFDi value curve is divided into curve A and curve B;

S44: curve B be take to axis Z and obtain its rotational symmetry curve C as axle, curve C and curve A are compared, obtain at ordinate value upper curve C and be greater than the part curve D that curve A or curve A are greater than curve C, according to the ordinate of curve D, be the proportional positions of asymmetric point in winding, determine transformer winding fault position.

86 dishes that have for this embodiment, the localization of fault of the high-power transformer of every dish 9 circles, result when selective resonance frequency is 27.4kHz is as shown in accompanying drawing 4,5, the relative deviation of resonance frequency and size show the symmetry about winding center, wherein the winding of accompanying drawing 4 is short circuit between dish, in figure, can find out when skew curve appears at IFDi numerical value and exceeds 58%, hence one can see that between dish, and short trouble position exceeds at IFDi numerical value on 58% position, and fault occurrence positions accounts for 80%～85% place of total winding length in the winding length apart from measuring input end.And another attached winding that single turn short circuit has occurred that Figure 5 shows that can find out that in figure skew curve appears at IFDi numerical value and exceeds 20% place, known fault occurrence positions accounts for 7%～13% place of total winding length in the winding length apart from measuring input end.

In another embodiment, carry out the detection of shorted-turn fault by voltage transfering function, the computing formula of wherein said voltage transfering function is

wherein, TF _vrepresent voltage transfering function, V _hthe input voltage that represents winding top terminal, V _obe illustrated in the output voltage of winding bottom terminals, w represents the frequency of input signal.Other technical scheme content and a upper embodiment are similar, at this, just no longer repeat to discuss.

The foregoing is only preferred embodiment of the present invention and oneself, not in order to limit the present invention, all any modifications of doing within the spirit and principles in the present invention, be equal to and replace and improvement etc., within all should being included in protection scope of the present invention.

Claims (8)

1. a detection method for high-power transformer shorted-turn fault, is characterized in that, comprises the steps:

S1: the structure adopting according to Transformer Winding, set up Transformer Winding and detection system model thereof;

S2: obtain respectively the transport function under the fault two states of intact He Za road, circle road according to Transformer Winding and detection system model thereof;

S3: calculate the standardization difference area of transport function under the fault two states of intact He Za road, described circle road, and judge the type of turn-to-turn short circuit according to standardization difference area value;

Standardization difference area SDA value is not equal to a zero indication transformer winding generation single turn short circuit, wherein, when being more than or equal to threshold value, standardization difference area SDA value represents to have occurred short circuit between dish, when SDA value is greater than zero and represents to have occurred single turn short circuit while being less than threshold value;

Area under the fault two states of intact He Za road, described standardization difference area Wei Za road under transfer curve poor;

S4: utilize frequency departure index to determine location of fault: first, draw frequency departure index curve diagram, then the proportional positions in winding is determined transformer fault position according to asymmetric point in figure.

2. detection method according to claim 1, is characterized in that, described transport function is curtage transport function, and the computing formula of described electric current and voltage transfering function is respectively:

with

Wherein, TF _crepresent current transfer function, TF _vrepresent voltage transfering function, V _hthe input voltage that represents winding top terminal, I _earthand V _othe output current and the output voltage that are illustrated respectively in winding bottom terminals, w represents the frequency of input signal.

3. detection method according to claim 1, is characterized in that, the computing formula of described step S3 Plays difference area is as follows:

$\mathrm{SDA}=\frac{{\∫}_{f_{\min }}^{f_{\max }}|{\mathrm{TF}}_{\mathrm{Test}}\left(f\right)-{\mathrm{TF}}_{\mathrm{Ref}}\left(f\right)|\mathrm{df}}{{\∫}_{f_{\min }}^{f_{\max }}{\mathrm{TF}}_{\mathrm{Ref}}\left(f\right)}$

Wherein, SDA is required standardization difference area, and fmin and fmax are respectively frequency domain minimum value and maximal value, TF _testfor the transport function under the malfunction of reality test Za road, TF _reftransport function under the intact state that do not break down in Wei Za road.

4. according to the detection method described in claim 2, it is characterized in that, the frequency w of input signal described in step S2 gets 100kHz, 1MHz and 100Hz to the arbitrary numerical value between 1MHz.

5. according to the detection method described in claim 2, it is characterized in that, the VH of input voltage described in step S2 is sinusoidal voltage, and amplitude is automatically adjusted between 100 and 240 volts.

6. according to the detection method described in claim 1-5 any one, it is characterized in that, described step S4 specifically comprises:

S41: fixing input end is arranged on through step S3 and has determined bottom terminals or the top terminal of the Transformer Winding of fault type, output terminal be take input end and to the winding other end, is moved as starting point, is repeatedly sampling and record the resonance frequency under corresponding surveyed winding length in input end different distance;

S42: calculate the frequency departure index in different distance, formula is as follows:

${\mathrm{IFD}}_i=\frac{{\mathrm{\Δf}}_i}{f_{o,i}}\×100\%=\left(\frac{f_{k,i}-f_{o,i}}{f_{o,i}}\right)\×100\%$

Wherein, IFD _irepresent frequency departure index, f _k,iand f _o,ii resonance frequency while representing respectively intact not the breaking down in malfunction Xia Heza road, circle road, subscript k is used for representing circle road malfunction, subscript o is used for representing the intact state that do not break down in circle road;

S43: the number percent and the IFD that account for respectively whole winding lengths with the winding length of tested use _ivalue for transverse and longitudinal coordinate, is drawn frequency departure index IFDi value curve map, take to pass through that tested winding length accounts for whole winding lengths 50% place and be axis Z perpendicular to the straight line of transverse axis, and IFDi value curve is divided into curve A and curve B;

S44: curve B be take to axis Z and obtain its rotational symmetry curve C as axle, curve C and curve A are compared, obtain at ordinate value upper curve C and be greater than the part curve D that curve A or curve A are greater than curve C, according to the ordinate of curve D, be the proportional positions of asymmetric point in winding, determine transformer winding fault position.

7. a pick-up unit for the high-power transformer shorted-turn fault based on transport function, is characterized in that, comprising:

System modeling module, for the structure adopting according to the winding of transformer, sets up Transformer Winding and detection system model;

Transport function detection module, obtains respectively the transport function under the intact two states in fault He Za road, circle road for Transformer Winding and the detection system model of setting up according to modeling detection module;

Fault type judge module, for calculating the standardization difference area of transport function under the intact two states in fault He Za road, described circle road, area under the intact two states in fault He Za road, described standardization difference area Wei Za road under transfer curve poor, judges the type of turn-to-turn short circuit according to standardization difference area value:

Standardization difference area SDA value is not equal to a zero indication transformer winding generation single turn short circuit, wherein when being more than or equal to threshold value, standardization difference area SDA value represents to have occurred short circuit between dish, when SDA value is greater than zero and represents to have occurred single turn short circuit while being less than threshold value;

Abort situation judge module, for utilizing frequency departure index to determine location of fault: draw frequency departure index curve diagram, the proportional positions according to asymmetric point in figure in winding can unique definite transformer fault position.

8. according to the pick-up unit described in claim 7, it is characterized in that, described abort situation judge module specifically for:

Fixing input end is arranged on through step S3 and has determined bottom terminals or the top terminal of the Transformer Winding of fault type, output terminal be take input end and to the winding other end, is moved as starting point, is repeatedly sampling and record the resonance frequency under corresponding surveyed winding length in input end different distance;

Calculate the frequency departure index in different distance, formula is as follows:

${\mathrm{IFD}}_i=\frac{{\mathrm{\Δf}}_i}{f_{o,i}}\×100\%=\left(\frac{f_{k,i}-f_{o,i}}{f_{o,i}}\right)\×100\%$

Wherein, IFD _irepresent frequency departure index, f _k,iand f _o,ii resonance frequency while representing respectively intact not the breaking down in malfunction Xia Heza road, circle road, subscript k is used for representing circle road malfunction, subscript o is used for representing the intact state that do not break down in circle road;

With the winding length of tested use, account for respectively number percent and the IFD of whole winding lengths _ivalue for transverse and longitudinal coordinate, is drawn frequency departure index IFDi value curve map, take to pass through that tested winding length accounts for whole winding lengths 50% place and be axis Z perpendicular to the straight line of transverse axis, and IFDi value curve is divided into curve A and curve B;

Curve B be take to axis Z and obtain its rotational symmetry curve C as axle, curve C and curve A are compared, obtain at ordinate value upper curve C and be greater than the part curve D that curve A or curve A are greater than curve C, according to the ordinate of curve D, be the proportional positions of asymmetric point in winding, determine transformer winding fault position.

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