CN110895322A - Interturn short circuit diagnosis method for solid insulation voltage transformer - Google Patents
Interturn short circuit diagnosis method for solid insulation voltage transformer Download PDFInfo
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- 238000009413 insulation Methods 0.000 title claims abstract description 47
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- 238000003745 diagnosis Methods 0.000 title claims abstract description 17
- 239000007787 solid Substances 0.000 title claims abstract description 16
- 238000012360 testing method Methods 0.000 claims abstract description 25
- 230000007547 defect Effects 0.000 claims abstract description 18
- 238000009863 impact test Methods 0.000 claims abstract description 8
- 238000002405 diagnostic procedure Methods 0.000 claims 1
- 238000001514 detection method Methods 0.000 abstract description 8
- 238000012216 screening Methods 0.000 abstract description 2
- 238000004804 winding Methods 0.000 description 7
- 238000011161 development Methods 0.000 description 6
- 238000010276 construction Methods 0.000 description 2
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- 238000007689 inspection Methods 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R35/00—Testing or calibrating of apparatus covered by the other groups of this subclass
- G01R35/02—Testing or calibrating of apparatus covered by the other groups of this subclass of auxiliary devices, e.g. of instrument transformers according to prescribed transformation ratio, phase angle, or wattage rating
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- G—PHYSICS
- 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
- G01R31/12—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing
Abstract
The invention relates to a turn-to-turn short circuit diagnosis method for a solid insulation voltage transformer, which comprises the following steps: step 1, constructing a waveform deviation coefficient and a difference coefficient based on voltage and current in an impact test or voltage and current data intercepted in a withstand voltage test; the difference coefficient comprises a mutual difference coefficient and a self-difference coefficient; step 2, judging the fault of the voltage transformer based on the size of the difference coefficient mean value; if the mean value of the mutual difference coefficients is far less than 10%, judging that the voltage transformer has no fault and no insulation damage; and if the mean value of the mutual difference coefficients is far more than 10%, judging that the voltage transformer has a fault or an insulation defect is serious. The turn-to-turn short circuit diagnosis method for the solid insulation voltage transformers is convenient to apply, simple to distinguish, high in detection reliability and high in detection efficiency, can be used for quickly screening fault conditions of a large number of solid insulation voltage transformers, can also be used for quickly diagnosing the fault conditions and severity of a single transformer, and can also be used for detecting whether the transformers pass various specified test items have insulation damage or not.
Description
Technical Field
The invention belongs to the technical field of turn-to-turn short circuit diagnosis of voltage transformers, and particularly relates to a turn-to-turn short circuit diagnosis method of a solid insulation voltage transformer.
Background
A voltage transformer is a voltage conversion device indispensable to a power transmission and supply system such as a power plant and a substation, and plays an important role as a common primary device in an electric power system. A voltage transformer is a special transformer of limited construction and use. The primary side of the voltage transformer is connected with a primary system, and the secondary side of the voltage transformer is connected with a measuring instrument, relay protection and the like.
The generator outlet voltage transformer plays an important role in measuring the outlet voltage of the generator, metering the outlet electric quantity and providing a voltage signal for relay protection, the insulation condition of the transformer is closely related to the safe and stable operation of the generator set, and once a fault occurs, the generator set is shut down in an unplanned manner, and the safe and stable operation of the system is influenced.
In recent years, the voltage transformers at the outlets of the generators frequently generate turn-to-turn short circuits in operation in domestic power generation groups, so that the non-stop faults of the generator sets are caused. Most of the existing test means aim at ground insulation of the mutual inductor, examination on turn-to-turn insulation is few, and early faults cannot be effectively found in preventive tests. The conventional detection method for detecting the turn-to-turn short circuit and the longitudinal insulation defect of the mutual inductor comprises the steps of measuring direct current resistance, no-load current, triple frequency withstand voltage and transformation ratio. However, the above method is difficult to completely determine the turn-to-turn short circuit, and for a transformer with a less serious turn-to-turn short circuit, problems are difficult to find through direct resistance, transformation ratio and no-load current inspection, and potential faults between turns are difficult to find through voltage resistance inspection because voltage which is evenly distributed between turns is small.
Disclosure of Invention
The invention aims to provide a turn-to-turn short circuit diagnosis method for a solid insulation voltage transformer, which diagnoses the fault of the voltage transformer at the outlet of a generator by taking lightning impulse voltage or withstand voltage test voltage at different time intervals as excitation, taking voltage and current at the measurable end of the voltage transformer as signal sources and taking the mean value of difference coefficients as criteria.
The invention provides a turn-to-turn short circuit diagnosis method for a solid insulation voltage transformer, which comprises the following steps of:
step 1, constructing a waveform deviation coefficient and a difference coefficient based on voltage and current in an impact test or voltage and current data intercepted in a withstand voltage test; the difference coefficients comprise mutual difference coefficients and self difference coefficients;
step 2, judging the fault of the voltage transformer based on the size of the difference coefficient mean value; if the mean value of the mutual difference coefficients is far less than 10%, judging that the voltage transformer has no fault and no insulation damage; and if the mean value of the mutual difference coefficients is far more than 10%, judging that the voltage transformer has a fault or an insulation defect is serious.
Further, the step 1 comprises:
the voltage and current of a measurable end under full voltage and drop voltage in an impulse voltage test are used as signal sources, impulse voltage and current of corresponding periods are divided into a series of harmonic waves, and waveform deviation coefficients and mutual and self-difference coefficients are constructed through transverse differences and longitudinal differences.
Further, the impulse test in step 1 is a lightning impulse test.
By means of the scheme, the turn-to-turn short circuit diagnosis method for the solid insulation voltage transformers is convenient to apply, simple to distinguish and high in detection reliability and efficiency, fault conditions (insulation defects) of a large number of solid insulation voltage transformers can be screened quickly, fault conditions and severity of a single transformer can be diagnosed quickly, and whether insulation damage exists in the transformers after various specified test items are passed can be checked (only voltage and current signals recorded by a measurable end of the voltage transformer exist).
The foregoing description is only an overview of the technical solutions of the present invention, and in order to make the technical solutions of the present invention more clearly understood and to implement them in accordance with the contents of the description, the following detailed description is given with reference to the preferred embodiments of the present invention and the accompanying drawings.
Drawings
Fig. 1 is a flow chart of a turn-to-turn short circuit diagnosis method of a solid insulated voltage transformer of the present invention.
Detailed Description
The following detailed description of embodiments of the present invention is provided in connection with the accompanying drawings and examples. The following examples are intended to illustrate the invention but are not intended to limit the scope of the invention.
Referring to fig. 1, the present embodiment provides a method for diagnosing turn-to-turn short circuit of a solid insulated voltage transformer, including the following steps:
step S1, constructing a waveform Deviation coefficient (development) and a difference coefficient (Othermess) based on the voltage and current in the impact test or the voltage and current data intercepted in the withstand voltage test; the difference coefficients comprise mutual difference coefficients and self difference coefficients;
step S2, judging the fault of the voltage transformer based on the average value of the difference coefficients; if the mean value of the mutual difference coefficients is far less than 10%, judging that the voltage transformer has no fault and no insulation damage; and if the mean value of the mutual difference coefficients is far more than 10%, judging that the voltage transformer has a fault or an insulation defect is serious.
Due to the nonlinear relation between the nonlinearity of the insulation defect and the external voltage and current, the performance under different half-wave and full-wave impacts has different characteristics, so that the waveform deviation coefficient and the difference coefficient under various harmonic voltages and currents have different values. If the tested object has no insulation defect, the mean value of the mutual difference coefficients is very small (less than 10%), and the mean value of the mutual difference coefficients with insulation defects is larger (more than 10%). If no fault exists and no insulation damage exists, the mean value of the coefficient of mutual difference is very small (far less than 10%); if the voltage transformer has a fault or insulation defects are serious, the mean value of the mutual difference coefficients is large (far more than 10%). The mutual difference coefficient mean criterion provided by the invention is sensitive to the insulation defect of the voltage transformer, and even can diagnose the partial discharge exceeding the standard.
In the present embodiment, step S1 includes:
the voltage and current of a measurable end under full voltage and drop voltage in an impulse voltage test are used as signal sources, impulse voltage and current of corresponding periods are divided into a series of harmonic waves, and waveform deviation coefficients and mutual and self-difference coefficients are constructed through transverse differences and longitudinal differences.
According to the turn-to-turn short circuit diagnosis method for the solid insulation voltage transformer, diagnosis criteria are constructed by using voltage and current in an impact test (or voltage and current intercepted in a withstand voltage test), and fault (insulation defect) analysis and diagnosis of the voltage transformer at the outlet of the generator are carried out. According to a half-wave and full-wave impact test (taking a lightning impact test as an example) of a voltage transformer winding, voltage and current amplitude values and phase angles of corresponding sections under different frequencies are obtained through two pressurization processes under full voltage and reduced voltage, namely, partial lightning impact voltage and current are divided into a series of harmonics, and a waveform Deviation coefficient (development) and a difference coefficient (otherness) are constructed. And according to the size of the difference coefficient mean value, analyzing and diagnosing faults (including fault hidden dangers) of the voltage transformer.
The invention uses the waveform Deviation coefficients (development) of the voltage and the current at the measurable end of the generator outlet voltage transformer at different time intervals to reflect different faults, defines the absolute value of the difference of the waveform Deviation coefficients at different time intervals as the difference coefficient (otherness), the difference coefficient can more sensitively and finely represent the influence degree of the fault or the hidden fault danger, the mean value of the difference coefficient can more comprehensively and completely represent the influence degree of the fault or the hidden fault danger, comprehensively represents the insulation condition of the whole generator outlet voltage transformer, and realizes the reliable analysis and diagnosis of the faults of the voltage transformer.
The present invention is described in further detail below.
In the first step, a signal source is obtained.
The signal source of the detection method provided by the invention is transient voltage and current generated from a voltage transformer winding. The lightning impulse voltage and current of the corresponding period are divided into a series of harmonic waves, and the mean value criterion of the difference coefficient of the insulation defect of the winding is constructed by using longitudinal and transverse differences. In the impulse voltage test, the voltage and the current of the measurable end under the full voltage and the reduced voltage are signal sources (or intercepted voltage and current signals corresponding to different periods of the withstand voltage test).
And secondly, constructing a discriminant function.
The invention relates to the faults of a voltage transformer, which comprise early faults and various fault hidden dangers, such as turn-to-turn short circuit, transverse and longitudinal insulation defects of windings and the like. The invention unifies various possible hidden troubles of faults into the change of equivalent parameters of the voltage transformer winding. Because the composite insulation has certain nonlinearity and anisotropy, the part with hidden trouble inevitably changes the uniformity of the whole winding, has specificity different from other parts of the winding, and has certain difference on the generated voltage and current under the excitation (source) action of different amplitudes and different equivalent frequencies, so that the mutual and self difference coefficients corresponding to the voltage and current can be constructed, and the fault analysis and diagnosis of the voltage transformer at the outlet of the generator can be realized according to the mean value and the threshold value of the mutual and self difference coefficients.
The invention provides a method for reflecting different faults by using waveform Deviation coefficients (development) of voltage and current at the measurable end of a voltage transformer at different time intervals, and defining the absolute value of the difference of the waveform Deviation coefficients at different time intervals as a difference coefficient (Othermess), wherein the difference coefficient can more sensitively and finely represent the influence degree of the faults or the hidden faults, the mean value of the difference coefficient can more comprehensively and completely represent the influence degree of the faults or the hidden faults, and the insulation condition of the whole voltage transformer is comprehensively represented, so that the fault analysis and diagnosis of the voltage transformer at the outlet of a generator are realized.
The difficulty and innovation of the invention is the proposition, construction method and calculation of the waveform Deviation coefficient (development) and difference coefficient (Othermass) and the mean value thereof.
With voltage, current u (t) and i (t), waveform Deviation coefficient (development) Dui(t, τ) is defined as:
Dui(t，τ)＝[u(t)-u(t-τ)]2[i(t)-i(t-τ)]2(1-1)
coefficient of variation (Othermess) Oui(t, τ) is defined as:
Oui(t，τ)＝|Dui(1)(t，τ)-Dui(2)(t，τ)| (1-2)
wherein O isui(t, τ) may be Oui(s)(t, τ) (coefficient of self-difference), or Oui(m)(t, τ) (coefficient of mutual difference), Dui(1)(t，τ)、Dui(2)(t, τ) represents the waveform deviation coefficient between the data of different periods in the half-wave or full-wave test (taking the impact test as an example).
Coefficient of variation (Othermess) OuiMean value of (t, τ)
Is defined as:
o when both the waveform deviation coefficient and the difference coefficient (Othermess) take discrete frequenciesuiMean value of (kf, τ)
Is defined as:
for the purpose of analysis, the present invention uses the waveform deviation factor Dui(t, τ) and coefficient of difference Oui(t, τ) are collectively referred to as generalized correlation coefficients.
And thirdly, calculating a waveform deviation coefficient and a difference coefficient.
Dividing the full wave into two sections of 0-25 mu s and 25 mu s-50 mu s, and calculating D corresponding to the front section and the rear sectionui(s)(kf, τ); dividing the half wave (amplitude reduction) into two sections of 0-25 mu s and 25 mu-50 mu s, and solving the D corresponding to the front section and the rear sectionui(s)(kf, τ); obtaining the sum of 0-25 μ s of the full waveHalf-wave D of 0-25 mu sui(m)(kf, τ) to obtain D of 25 μ s-50 μ s for full wave and 25 μ s-50 μ s for half waveui(m)(kf, τ); finding Oui(s)(kf, τ) and Oui(m)(kf，τ)。
And selecting data of one time period as a reference, comparing data of another time period under the same voltage level, and comparing the magnitude of the correlation coefficients of the data by generalized correlation function analysis.
The transverse comparison only has one set of correlation coefficients, has no comparability, and needs to be compared with two sets of correlation coefficients of an longitudinal comparison method for determination. If the correlation coefficient of the transverse comparison is consistent with the size of the longitudinal comparison method, the test sample is not obviously changed under the pressurization condition, the test sample has no insulation defect, and the correlation coefficient with the insulation defect is small.
And fourthly, calculating the mean value of the difference coefficients.
The mean value of the coefficient of self-variation is obtained from the formula (1-4)
Sum and difference coefficient mean
By the mean of the coefficients of mutual difference
For the criterion, diagnosing the fault or insulation defect (mean value of self-difference coefficient) of the voltage transformer
As an auxiliary criterion). The test shows that
Less than 10% is no failure,
more than 10% is faulty, the smaller the insulation performance, the better, the larger the fault or insulation fault.
And fifthly, analyzing results.
The detection method provided by the invention is convenient to apply, simple to distinguish, and obviously higher in detection reliability and efficiency than the existing detection method. The method can be used for rapidly screening fault conditions (insulation defects) of a large quantity of solid insulation voltage transformers, rapidly diagnosing the fault conditions and severity of a single transformer, and testing whether insulation damage exists in the transformers after various specified test items are passed (as long as voltage and current signals recorded by a measurable end of the voltage transformer exist).
The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, it should be noted that, for those skilled in the art, many modifications and variations can be made without departing from the technical principle of the present invention, and these modifications and variations should also be regarded as the protection scope of the present invention.
Claims (3)
1. A turn-to-turn short circuit diagnosis method for a solid insulation voltage transformer is characterized by comprising the following steps:
step 1, constructing a waveform deviation coefficient and a difference coefficient based on voltage and current in an impact test or voltage and current data intercepted in a withstand voltage test; the difference coefficients comprise mutual difference coefficients and self difference coefficients;
step 2, judging the fault of the voltage transformer based on the size of the difference coefficient mean value; if the mean value of the mutual difference coefficients is far less than 10%, judging that the voltage transformer has no fault and no insulation damage; and if the mean value of the mutual difference coefficients is far more than 10%, judging that the voltage transformer has a fault or an insulation defect is serious.
2. The solid insulated voltage transformer turn-to-turn short diagnostic method according to claim 1, wherein said step 1 comprises:
the voltage and current of a measurable end under full voltage and drop voltage in an impulse voltage test are used as signal sources, impulse voltage and current of corresponding periods are divided into a series of harmonic waves, and waveform deviation coefficients and mutual and self-difference coefficients are constructed through transverse differences and longitudinal differences.
3. The method for diagnosing turn-to-turn short circuit of a solid-insulated voltage transformer according to claim 2, wherein the surge test in step 1 is a lightning surge test.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112526306A (en) * | 2020-11-24 | 2021-03-19 | 中国大唐集团科学技术研究院有限公司火力发电技术研究院 | Generator outlet side voltage transformer insulation state monitoring system |
| CN116224154A (en) * | 2023-03-02 | 2023-06-06 | 湖南贝特新能源科技有限公司 | Short circuit detection tool and detection method for compressor |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101988945A (en) * | 2009-08-07 | 2011-03-23 | 华东电力试验研究院有限公司 | Method for diagnosing interturn short circuit of rotor winding |
| CN106526406A (en) * | 2016-12-13 | 2017-03-22 | 华北电力科学研究院有限责任公司 | Inter-tern short-circuit detection device, analysis method and device for voltage transformer |
| CN106950470A (en) * | 2017-03-10 | 2017-07-14 | 三峡大学 | A kind of method for diagnosing faults of the transformer lightning impulse based on big data |
-
2019
- 2019-10-31 CN CN201911058147.5A patent/CN110895322A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101988945A (en) * | 2009-08-07 | 2011-03-23 | 华东电力试验研究院有限公司 | Method for diagnosing interturn short circuit of rotor winding |
| CN106526406A (en) * | 2016-12-13 | 2017-03-22 | 华北电力科学研究院有限责任公司 | Inter-tern short-circuit detection device, analysis method and device for voltage transformer |
| CN106950470A (en) * | 2017-03-10 | 2017-07-14 | 三峡大学 | A kind of method for diagnosing faults of the transformer lightning impulse based on big data |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112526306A (en) * | 2020-11-24 | 2021-03-19 | 中国大唐集团科学技术研究院有限公司火力发电技术研究院 | Generator outlet side voltage transformer insulation state monitoring system |
| CN116224154A (en) * | 2023-03-02 | 2023-06-06 | 湖南贝特新能源科技有限公司 | Short circuit detection tool and detection method for compressor |
| CN116224154B (en) * | 2023-03-02 | 2023-12-05 | 湖南贝特新能源科技有限公司 | Short circuit detection tool and detection method for compressor |
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