CN104280449B - Paper oil insulation equipment micro-water content qualitative evaluation method based on the sub-spectral line of relaxation - Google Patents

Abstract

The present invention relates to a kind of paper oil insulation equipment micro-water content qualitative evaluation method based on the sub-spectral line of relaxation.First the method measures the depolarization current of paper oil insulation equipment, then depolarization current Differential Spectrum function is gradually carried out spectrum unscrambling, show lying in the micro-water content information within depolarization current with the form of sub-spectral line, and in this, as the qualitative evaluation method of paper oil insulation equipment micro-water content situation, if the sub-spectral line that paper oil insulation equipment depolarization current spectral line parses is the most, then show that the micro-water content of paper oil insulation equipment is the biggest, otherwise, if the sub-spectral line that differential spectral line parses is the fewest, then show that the micro-water content of paper oil insulation equipment is the least.The appraisal procedure that the present invention proposes provides a kind of intuitive and accurate analysis means for paper oil insulation equipment micro-water content qualitative evaluation.

Description

Paper oil insulation equipment micro-water content qualitative evaluation method based on the sub-spectral line of relaxation

Technical field

The present invention proposes a kind of paper oil insulation equipment micro-water content qualitative evaluation method based on the sub-spectral line of relaxation, the method Relate to the assessment technology field of paper oil insulation equipment micro-water content.

Background technology

The main method being currently used for oiled paper insulated micro water content assessment has: karl Fischer titration, dew point method, oilpaper water Balance-dividing relation curve method and electric-diagnosis method based on dielectric response theory etc..Karl Fischer titration needs from oil Paper insulation device interior extracts insulation sample and tests, and may damage equipment during sampling；Dew point method Process of the test needs breaking vacuum, and is difficult to obtain experimental data；Application Oil-Paper Moisture Equilibrium curve method measures in insulating oil Micro-water content there is also the most limiting, and accuracy need to improve further.Based on dielectric response theory electric Diagnostic method mainly has recovery voltage measurement method and polarization depolarization current mensuration, and these methods are by matching electric characteristic Curve between amount and the micro-water content of insulation system, is diagnosed to be the micro-water content situation of paper oil insulation equipment indirectly.But these Diagnostic method lacks consideration to the impact of temperature, humidified insulation and external interference factor etc., therefore it cannot obtain in practice Extensively application.Therefore the paper oil insulation equipment micro-water content qualitative evaluation based on depolarization current spectral line analytic method that invention proposes Method, the qualitative evaluation for paper oil insulation equipment micro-water content provides one analysis means intuitively and accurately, and it is in actual work Journey has important using value.

Summary of the invention

It is an object of the invention to provide a kind of paper oil insulation equipment micro-water content qualitative evaluation based on the sub-spectral line of relaxation Method, the method can intuitively, accurately and reliably judge the micro-water content situation of paper oil insulation equipment.

For achieving the above object, the technical scheme is that a kind of paper oil insulation equipment based on the sub-spectral line of relaxation is micro- Water content qualitative evaluation method, sequentially includes the following steps:

Step 1: paper oil insulation equipment is carried out depolarization current measurement, obtains depolarization current spectral line i_d；

Step 2: step 1 is measured the depolarization current spectral line obtained and carries out differential spectrum unscrambling, obtain depolarization current i_d's Differential Spectrum function；

Step 3: to Differential Spectrum functionGradually carry out parsing and obtain each sub-spectral line；

Step 4: judge micro-aqueous condition of paper oil insulation equipment qualitatively according to the sub-spectral line number parsed, if parsing Sub-spectral line quantity the most, then show that the micro-water content of paper oil insulation equipment is the biggest.

Further, in step 1, described depolarization current measurement process is as follows: first at paper oil insulation equipment the two poles of the earth Apply high-voltage dc pulse U₀, in time period t_cInterior to paper oil insulation equipment charge, it is then turned off applied voltage and in time period t_d Interior dielectric depolarization current i is flow through in the two poles of the earth short circuit measurement of paper oil insulation equipment_d, its function expression is:

(1)

In formula, C₀For vacuum electric capacitance；N represents paper oil insulation device interior difference dielectric relaxation mechanism number, A_iAnd τ_i Representing weight coefficient and the relaxation response time of i-th RELAXATION MECHANISM respectively, they are constant；I_di=C₀U₀A_iBe one often Number, it represents the contribution to depolarization current of the i-th RELAXATION MECHANISM.

Further, in step 2, the described calculating process to depolarization current spectral line differential spectrum unscrambling is as follows:

To described depolarization current i_dIt is multiplied by the depolarising time t of correspondence after differentiating again, is depolarized The differential spectral line of electric currentFor:

(2)

Make in above formula, claim L_iIt it is the i-th strip spectral line.

Further, in step 3, described to Differential Spectrum functionGradually carry out parsing and obtain each sub-spectral lineProcess as follows:

From differential spectral lineEnd starts, and arbitrarily takes two pointsWith, set up following equations group:

(3)

I is obtained by formula (3)_d1With, then substitute into, the 1st strip spectral line L can be obtained₁；

The most again by differential spectral lineDeduct the 1st strip spectral line L₁Obtain remaining differential spectral line；Again from surplus Remaining differential spectral lineEnd start, appoint take two points value substitute into formula (3), obtain I_d2With, substitute into the most again, the 2nd strip spectral line L can be obtained₂；

According to above-mentioned analytic method, can obtain the 3rd article successively, the 4th article to the sub-spectral line of nth bar；I & lt that and if only if resolves Residue differential spectral lineWhen the absolute value of middle peak-peak is less than the threshold value preset, then terminate resolving.

The invention has the beneficial effects as follows, it is proposed that a kind of paper oil insulation equipment micro-water content based on the sub-spectral line of relaxation is qualitative Appraisal procedure.The method, by gradually resolving paper oil insulation equipment depolarization current electricity spectral line, will lie in depolarising The micro-water content information of current internal shows with the form of sub-spectral line, and in this, as paper oil insulation equipment micro-water content Qualitative evaluation；The qualitative evaluation that the method is paper oil insulation equipment micro-water content provides a kind of intuitive and accurate analysis means, Practical Project has important using value；It is noted that the present invention has obtained project of national nature science fund project (61174117) subsidizing, the technical scheme of the method has proven to have good Evaluated effect.

Accompanying drawing explanation

Fig. 1 is the flow chart realizing the inventive method.

Fig. 2 is the i-th strip spectrum that the present invention proposes.

Fig. 3 is the differential spectral line after the sub-Spectral Overlapping of difference that the present invention proposes.

Fig. 4 is transformer T in the embodiment of the present invention₁、T₂And T₃Depolarization current experiment curv.

Fig. 5 a-5e is respectively T in the embodiment of the present invention₁The sub-spectral line that transformer solution is composed and residue differential spectral line.

Fig. 6 a-6f is respectively T in the embodiment of the present invention₂The sub-spectral line that transformer solution is composed and residue differential spectral line.

Fig. 7 a-7h is respectively T in the embodiment of the present invention₃The sub-spectral line that transformer solution is composed and residue differential spectral line.

Detailed description of the invention

Below in conjunction with the accompanying drawings, technical scheme is specifically described.

A kind of paper oil insulation equipment micro-water content qualitative evaluation method flow diagram based on the sub-spectral line of relaxation of the present invention, such as figure Shown in 1；It comprises the following steps:

Step 1: the depolarization current spectral line measuring acquisition is carried out differential and obtains Differential Spectrum function:

(2)

Step 2: from Differential Spectrum functionEnd starts, and arbitrarily takes two points、, set up following Equation group:

(3)

Unknown quantity I is obtained by formula (3)_d1WithRear substitution, the 1st strip spectral line can be obtained L₁；

Step 3: by differential spectral lineDeduct the 1st strip spectral line L₁Obtain remaining differential spectral line.Again from surplus Remaining differential spectral lineEnd start, appoint take two points value substitute into formula (3), obtain I_d2With, substitute into the most again, the 2nd strip spectral line L can be obtained₂。

Step 4: according to above-mentioned analytic method, can obtain the 3rd article successively, the 4th article ..., the sub-spectral line of nth bar.When and only When the residue differential spectral line that i & lt resolvesWhen the absolute value of middle peak-peak is less than the threshold value preset, then terminate resolving.

Step 5: contain according to the sub-spectral line quantity qualitative evaluation micro-water of paper oil insulation equipment that depolarization current spectral line parses Amount situation.If

Sub-spectral line quantity is the most, then show that the micro-water content of paper oil insulation equipment is the biggest.Otherwise, if sub-spectral line quantity is more Few, then show that the micro-water content of paper oil insulation equipment is the least.

Below in conjunction with the accompanying drawings and the present invention is described in further detail by specific embodiment.

First high-voltage dc pulse U is applied at paper oil insulation equipment the two poles of the earth₀(U₀Value is 500-1000V), in time period t_cIn To paper oil insulation equipment charge, it is then turned off applied voltage and in time period t_dInterior by the two poles of the earth short circuit measurement of paper oil insulation equipment Flow through dielectric depolarization current i_d, its function expression is:

(1)

In formula, C₀For vacuum electric capacitance；N represents paper oil insulation device interior difference dielectric relaxation mechanism number, A_iAnd τ_i Representing weight coefficient and the relaxation response time of i-th RELAXATION MECHANISM respectively, they are constant；I_di=C₀U₀A_iBe one often Number, it represents the contribution to depolarization current of the i-th RELAXATION MECHANISM.

Depolarization current i_dSpectral line, in addition to comprising Oil-Paper Insulation dielectric relaxation response message, also comprises absolutely simultaneously Edge paper cellulose makes moist and the product such as micro-water in insulating oil, and they occur dielectric polarizations product external voltage (electric field) effect is lower Raw depolarization current implies the micro-water amount information within insulation system.When the micro-water content within insulation system is the most, go to pole The sub-spectral line that galvanic current parses is the most.The number of the most sub-spectral line can set by qualitative reflection paper oil insulation to a certain extent Standby micro-water content situation.

As can be seen here, if all sub-spectral line lain in depolarization current spectral line is all resolved and shows, just can be accurate True ground qualitative evaluation goes out the micro-water content situation of paper oil insulation equipment.Now to formula (1) depolarization current i_dDifferentiate, then It is multiplied by the depolarising time t of correspondence, obtains the Differential Spectrum function of depolarization currentFor:

(2)

Make in above formula, claim L_iIt it is the i-th strip spectral line.As shown in Figure 2.

For analyzing sub-spectral line L further_iCharacter, rightDerivation can obtain again:

Analyzed by above formula it follows that work asTime,, sub-spectral line L_iIt it is monotonic increase；WhenTime,, sub-spectral line L_iIt it is monotone decreasing；And if only ifTime,, the most sub-spectral line L_i One peak point of unique existence.

Analyze according to above, sub-spectral line L_iHave characteristics that 1) sub-spectral lineIt is a function with single peak value, At time t=τ_iTime reach peak point, then changing over gradually decays in the both sides of peak point finally levels off to 0；2) by InValue size different, the most each strip spectral line The time corresponding to peak point also Different, therefore Differential Spectrum functionCurve be the sub-Spectral Overlapping different by the single peak value of n bar and peak Sum, as shown in Figure 3；3) whenValue more hour, corresponding sub-spectral lineDecay the fastest, on the contrary sub-spectral lineDecline Subtract the slowest, thereforeIt is worth the biggest sub-spectral line pairThe end contribution of spectral line is the biggest.Otherwise contributing the least, it is rightThe impact of spectral line end is negligible.

By sub-spectral lineCharacteristic understand, Differential Spectrum functionSon spectrum by various different relaxation information Line superposition, as long as by sub-spectral line successively from Differential Spectrum functionIn parse, just can go out paper oil insulation by qualitative evaluation The micro-water content situation of equipment.If the insulating paper cellulose of paper oil insulation equipment makes moist and micro-water yield contained in insulating oil is the most Time, then the sub-spectral line quantity parsed is the most.As can be seen here, how many numbers of sub-spectral line can set by qualitative reflection paper oil insulation Standby micro-water content situation.

The resolving of depolarization current spectral line is as follows:

Step 1: depolarization current spectral line measurement obtained carries out differential, obtains Differential Spectrum function。

Step 2: from Differential Spectrum functionEnd starts, and arbitrarily takes two points、, set up following Equation group:

(3)

Unknown quantity I is obtained by formula (3)_d1WithRear substitution, the 1st strip spectral line L can be obtained₁。

Step 3: by differential spectral lineDeduct the 1st strip spectral line L₁Obtain remaining differential spectral line.Again from residue Differential spectral lineEnd start, appoint take two points value substitute into formula (3), obtain I_d2With, substitute into the most again, the 2nd strip spectral line L can be obtained₂。

Step 4: according to above-mentioned analytic method, can obtain the 3rd article successively, the 4th article ..., the sub-spectral line of nth bar.When and only When the residue differential spectral line that i & lt resolvesWhen the absolute value of middle peak-peak is less than the threshold value preset, then terminate resolving.

The criterion of qualitative evaluation paper oil insulation equipment micro-water content situation is can be inferred that by above analysis.

Criterion: paper oil insulation equipment micro-water content situation can apply the number of the sub-spectral line that polarization current parses to carry out Qualitative evaluation.If the sub-spectral line number that paper oil insulation equipment depolarization current differential spectral line parses is the most, then show oilpaper The micro-water content of insulator arrangement is the biggest.Otherwise, if the sub-spectral line that depolarization current differential spectral line parses is less, then the bright paper of oil meter The micro-water content of insulator arrangement is less.

The qualitative evaluation step of paper oil insulation equipment micro-water content situation is:

Step 1 measures paper oil insulation equipment depolarization current i_dAnd spectral line.

Step 2 carries out differential by formula (2) to depolarization current spectral line, obtains Differential Spectrum function。

Step 3 is according to the resolving of depolarization current spectral line, from Differential Spectrum functionIn parse successively each Strip spectral line L_i , during until the absolute value of peak-peak is less than the threshold value preset in residue differential spectral line, then terminate Resolve.

Step 4, according to paper oil insulation equipment micro-water content criterion, evaluates paper oil insulation equipment micro-water content situation.

The paper oil insulation equipment micro-water content qualitative evaluation the method now present invention proposed and operating procedure, be applied to table 1 The micro-water content of the transformer that shown three different models, micro-water content are different is estimated.

According to the measuring method of depolarising electricity, at paper oil insulation equipment the two poles of the earth plus high-voltage dc pulse U₀For 1000V, fill It is respectively discharge time 5000 seconds and 2500 seconds, measures the depolarization current curve of three transformers as shown in Figure 4.

Analytic method according to paper oil insulation equipment depolarization current spectral line and operating procedure, respectively to T₁、T₂And T₃Three The depolarization current electricity spectral line of platform transformer resolves, and can obtain each sub-spectral line and final residue differential spectral line such as Fig. 5 a- Shown in 5e, Fig. 6 a-6f, Fig. 7 a-7h, threshold value all takes 0.01.

From Fig. 5 a-5e, Fig. 6 a-6f, Fig. 7 a-7h respectively it can be seen that T₁The depolarization current Differential Spectrum function of transformer4 strip spectral lines, T can be parsed₂The depolarization current Differential Spectrum function of transformerCan resolve Go out 5 strip spectral lines, T₃The depolarization current Differential Spectrum function of transformer7 strip spectral lines can be parsed.

According to the analysis result of these three sub-spectral lines of transformer, application paper oil insulation equipment micro-water content qualitative evaluation is sentenced According to, then can judge the micro-water content situation of these three transformers: T respectively₁The sub-spectral line number that transformer parses is minimum, and it is micro- Water content is minimum；T₃The sub-spectral line number that transformer parses is most, and its micro-water content is the most most；T₂The son that transformer parses Spectral line compares T₁Many, but compare T₃Lack, then its micro-water content be more than T₁Transformer, but compare T₃The micro-water content of transformer is few.

As can be seen here, above qualitative evaluation result matches with the actual conditions of three transformers, is worth mentioning It is that the present invention has obtained project of national nature science fund project (61174117) and subsidized, and the technical scheme of the method has proven to be had Good Evaluated effect.

Being above presently preferred embodiments of the present invention, all changes made according to technical solution of the present invention, produced function is made With during without departing from the scope of technical solution of the present invention, belong to protection scope of the present invention.

Claims (4)

1. a paper oil insulation equipment micro-water content qualitative evaluation method based on the sub-spectral line of relaxation, it is characterised in that: include as Lower step,

Step 1: paper oil insulation equipment is carried out depolarization current measurement, obtains depolarization current spectral line i_d；

Step 2: step 1 is measured the depolarization current spectral line obtained and carries out differential spectrum unscrambling, obtain depolarization current i_dDifferential Spectrum Function H (t, τ_i,i_di)；

Step 3: to Differential Spectrum function H (t, τ_i,i_di) gradually carry out parsing and obtain each sub-spectral line L_i(t,τ_i,i_di)；

Step 4: qualitatively judge micro-aqueous condition of paper oil insulation equipment according to the sub-spectral line number parsed, if the son spectrum parsed Line quantity is the most, then show that the micro-water content of paper oil insulation equipment is the biggest.

Paper oil insulation equipment micro-water content qualitative evaluation method based on the sub-spectral line of relaxation the most according to claim 1, its Being characterised by: in step 1, it is as follows that described depolarization current measures process: first apply high pressure at paper oil insulation equipment the two poles of the earth DC pulse U₀, in time period t_cInterior to paper oil insulation equipment charge, it is then turned off applied voltage and in time period t_dInterior by oilpaper Dielectric depolarization current i is flow through in the two poles of the earth short circuit measurement of insulator arrangement_d, its function expression is:

$i_d\left(t\right)=C_0{U}_0\underset{i=1}{\overset{n}{\Σ}}{A}_i{e}^{-t/{\mathrm{\τ}}_i}=\underset{i=1}{\overset{n}{\Σ}}{I}_{di}{e}^{-t/{\mathrm{\τ}}_i}---\left(1\right)$

In formula, C₀For vacuum electric capacitance；N represents paper oil insulation device interior difference dielectric relaxation mechanism number, A_iAnd τ_iRespectively Representing weight coefficient and the relaxation response time of i-th RELAXATION MECHANISM, they are constant；I_di=C₀U₀A_iIt is a constant, it Represent the contribution to depolarization current of the i-th RELAXATION MECHANISM.

Paper oil insulation equipment micro-water content qualitative evaluation method based on the sub-spectral line of relaxation the most according to claim 2, its Being characterised by: in step 2, the described calculating process that depolarization current spectral line carries out differential spectrum unscrambling is as follows:

To described depolarization current i_dIt is multiplied by the depolarising time t of correspondence after differentiating again, obtains the micro-of depolarization current Open score line H (t, τ_i,I_di) it is:

$H(t,{\mathrm{\τ}}_i,I_{di})=-t\frac{{\mathrm{di}}_d}{dt}=\underset{i=1}{\overset{n}{\Σ}}{I}_{di}(t/{\mathrm{\τ}}_i)\exp (-(t/{\mathrm{\τ}}_i\left)\right)=\underset{i=1}{\overset{n}{\Σ}}{L}_i(I_{di},t,{\mathrm{\τ}}_i)---\left(2\right)$

Make L in above formula_i(I_di,t,τ_i)=I_di(t/τ_i)exp(-(t/τ_i)), claim L_iIt it is the i-th strip spectral line.

Paper oil insulation equipment micro-water content qualitative evaluation method based on the sub-spectral line of relaxation the most according to claim 3, its It is characterised by: in step 3, described to Differential Spectrum function H (t, τ_i,i_di) gradually carry out parsing and obtain each sub-spectral line L_i(t,τ_i, i_di) process as follows:

From differential spectral line H (t, τ_i,I_di) end starts, and arbitrarily takes two point (t₁,H₁) and (t₂,H₂), set up following equations group:

$\left\{\begin{array}{c}{H}_1-I_{d1}(t_1/{\mathrm{\τ}}_1)\exp (-(t_1/{\mathrm{\τ}}_1))=0\\ H_2-I_{d1}(t_2/{\mathrm{\τ}}_1)\exp (-(t_2/{\mathrm{\τ}}_1))=0\end{array}\right.---\left(3\right)$

I is obtained by formula (3)_d1And τ₁, then substitute into I_d1(t/τ₁)exp(-(t/τ₁)) the 1st strip spectral line L can be obtained₁；

The most again by differential spectral line H (t, τ_i,I_di) deduct the 1st strip spectral line L₁Obtain remaining differential spectral line S₁(·)；Again from residue Differential spectral line S₁The end of () starts, and appoints the value taking two points to substitute into formula (3), obtains I_d2And τ₂, substitute into I the most again_d2(t/ τ₂)exp(-(t/τ₂)), the 2nd strip spectral line L can be obtained₂；

According to above-mentioned analytic method, the 3rd article can be obtained successively, the 4th article to the sub-spectral line of nth bar；It is surplus that i & lt that and if only if resolves Remaining differential spectral line S_iWhen in (), the absolute value of peak-peak is less than the threshold value preset, then terminate resolving.