CN104569320B - In application insulating oil, acid number and moisture measure the method for moisture in insulating paper - Google Patents

Abstract

The present invention relates to a kind of apply the method for moisture during acid number and moisture measure insulating paper in insulating oil, it comprises the following steps successively: (a) takes the insulating oil of oil-immersed power transformer in work, temperature T of the real time measure insulating oil；B () takes the insulating oil of part mensuration excess temperature and is placed in karl Fischer titrator, measure the content W of wherein moisture_oil；C () takes the insulating oil of part mensuration excess temperature again and is placed in automatic acid value tester, measure its acid number A_c；D () utilizes formula (1) can calculate the weight/mass percentage composition W of moisture in insulating paper_paper,(1).The assay method of moisture in insulating paper of the present invention, it, only by measuring the temperature of insulating oil, moisture and acid number, then utilizes formula (1) can be calculated moisture in insulating paper, and not only step is greatly decreased, and simple to operate, taken time seldom, measure accurately.

Description

In application insulating oil, acid number and moisture measure the method for moisture in insulating paper

Technical field

The invention belongs to electricity device field, relate to the assay method of a kind of moisture, be specifically related to a kind of application absolutely In edge oil, acid number and moisture measure the method for moisture in insulating paper.

Background technology

Oil-immersed power transformer is one of key equipment of power system.Research shows, the transformator event of the overwhelming majority Barrier is caused by interior Insulation Problems.Oil-paper combination insulation, as the major insulation system of inside transformer, is chronically at high temperature, tide Under the adverse circumstances such as wet, chemical attack and electromagnetic field, its insulating properties can significantly reduce, thus causes the mechanical life of transformator With electrical endurance serious curtailment.Insulating oil in oil-paper combination insulation can pass through oil strain, the measure such as change oil recovers its insulating properties, And insulating paper be difficult to change and aging be irreversible, therefore the degree of aging of insulating paper directly determines the use of transformator Life-span.Hydrolytic degradation is the principal mode that insulating paper is aging, and in insulating paper, moisture doubles, and its mechanical life halves, Heat ageing speed also will be accelerated at double；In insulating paper, moisture is many and is affected and inconspicuous by oil strain, the measure such as change oil, its Testing index as insulating paper ageing state has higher reliability.

The parameter that current internationally recognized judgement insulating paper reaches end of life is insulation paper polymerization degree.Insulation paper polymerization degree It it is the degree of aging that can truly reflect insulating paper.DL/T 596-2005 " power equipment preventive trial code " recommends polymerization When degree is less than 250, should arouse attention.But transformator need to be drained the oil and be hung cover by the test of the degree of polymerization, not only implement difficulty big, May also result in the damage of insulation.For the oil-filled transformer put into operation, owing to being difficult to directly obtain insulating paper sample, In test insulating paper during water content, the most first use Karl_Fischer method, i.e. KFT (Karl Fischer Titration) method is tested Moisture in insulating oil, obtains the moisture in insulating paper further according to the Oil-Paper Insulation moisture distribution profile of equilibrium； The currently used paper oil insulation moisture distribution profile of equilibrium is mainly Oommen curve.Oommen curve is used to need moisture absolutely Edge oil reaches poised state with insulating paper, the longest, and trivial operations, therefore uses the method test easy not and accurate. And insulating paper is aging can produce the organic acid such as formic acid, aphthenic acids, organic acid can affect moisture between insulating oil and insulating paper Concentration distribution, point out in insulating oil that acid number may be used for characterizing paper oil insulation degree of aging, therefore for running the time limit simultaneously Longer transformator, the degree of aging of its insulating paper is relatively deep, uses moisture in Oommen curve determination insulating paper to bring Bigger error.

Summary of the invention

The invention aims to overcome the deficiencies in the prior art to provide acid number and moisture in a kind of application insulating oil to contain The method of moisture in measurement insulating paper.

For reaching above-mentioned purpose, the technical solution adopted in the present invention is: in a kind of application insulating oil, acid number and moisture contain The method of moisture in measurement insulating paper, it comprises the following steps successively:

A () takes the insulating oil of oil-immersed power transformer in work, temperature T of the real time measure insulating oil；

B () takes the insulating oil of part mensuration excess temperature and is placed in karl Fischer titrator, measure the content of wherein moisture W_oil；

C () takes the insulating oil of part mensuration excess temperature again and is placed in automatic acid value tester, measure its acid number A_c；

D () utilizes formula (1) can calculate the weight/mass percentage composition W of moisture in insulating paper_paper,

$W_{\mathrm{paper}}=16.59e^{-0.0423\×T}{[{10}^{7.8825\frac{2191.8}{273.15+T}}\×\frac{W_{\mathrm{oil}}}{{10}^{7.26-\frac{1618.3}{273.15+T}+0.9384\×A_c}}]}^{0.0058\×T+0.3478}---\left(1\right).$

Optimally, described temperature T is 10 DEG C～100 DEG C.

Optimally, in step (b) and step (c), the amount of taking of described insulating oil is 1～10 milliliter.

Owing to technique scheme is used, the present invention compared with prior art has the advantage that present invention application insulation In oil, acid number and moisture measure the method for moisture in insulating paper, and it is only by measuring the temperature of insulating oil, moisture Content and acid number, then utilize formula (1) can be calculated moisture in insulating paper, and not only step is greatly decreased, and Simple to operate, taken time seldom, measure accurately.

Figure of description

Fig. 1 is experimental facilities layout drawing of the present invention；

Wherein, 1 is glass drying oven, and 2 is aqueous glycerol solution, and 3 is perforated baffle, and 4 is open glass bottle, and 5 is insulating paper, 6 is insulating oil, and 7 is calorstat, and 8 is Temperature Humidity Sensor, and 9 is humiture monitor, and 10 is 1# sample, and 11 is 2# sample, 12 For 3# sample, 13 is 4# sample.

Detailed description of the invention

In present invention application insulating oil, acid number and moisture measure the method for moisture in insulating paper, and it includes successively Following steps: (a) takes the insulating oil of oil-immersed power transformer in work, temperature T of the real time measure insulating oil；B () takes part The insulating oil measuring excess temperature is placed in karl Fischer titrator, measures the content W of wherein moisture_oil；C () takes part again and measures The insulating oil of excess temperature is placed in automatic acid value tester, measures its acid number A_c；D () utilizes formula (1) can calculate insulating paper The weight/mass percentage composition W of middle moisture_paper,

$W_{\mathrm{paper}}=16.59e^{-0.0423\×T}{[{10}^{7.8825\frac{2191.8}{273.15+T}}\×\frac{W_{\mathrm{oil}}}{{10}^{7.26-\frac{1618.3}{273.15+T}+0.9384\×A_c}}]}^{0.0058\×T+0.3478}---\left(1\right).$

It should be noted that temperature T to be determined is preferably 10 DEG C～100 DEG C；In step (b) and step (c), insulating oil The amount of taking is preferably 1～10 milliliter, and the data so measured are more accurate.

The principle that said determination method relates to is as follows: water saturation dissolubility and insulating oil temperature in aging insulating oil, In insulating oil, the relation of acid number meets Arrhenius equation, can be expressed as:

$W_s={10}^{A-\frac{B}{273.15+T}+m\×A_c}---\left(2\right);$

In formula, W_sBeing water saturation dissolubility in insulating oil, unit is ppm；T is the temperature of insulating oil, and unit is DEG C；A Being coefficient of association with B, constituent with insulating oil, chemical property etc. are relevant；M be the translation relevant to acid number in insulating oil because of Son.

Adsorption isotherm (Freundlich Isotherm Equation), paper oil insulation system is wished according to Freund profit Middle absorption moisture in insulating paper can be expressed as:

W_paper=cPⁿ(3)；

In formula, W_paperIt is the content of moisture in insulating paper, represents by weight/mass percentage composition or mass percent (%)；C is Adsorption equilibrium costant, typically reduces with the rising of temperature；N is to characterize the parameter that material absorption property is strong and weak；P is adsorbed component (water vapour) equilibrium partial pressure in the gas phase, unit is kPa.

Again due to the relative humidity (RH in air_air) refer at identical temperature, water vapor in air pressure (P) and saturation water Vapour pressure (P_s) percentage ratio, as shown in Equation 4:

${\mathrm{RH}}_{\mathrm{air}}=\frac{P}{P_s}\×100\%---\left(4\right);$

Relative humidity (RH in insulating oil_oil) refer at identical temperature, moisture (W in insulating oil_oil) satisfy with moisture With dissolubility (W_s) percentage ratio, as shown in formula (5):

${\mathrm{RH}}_{\mathrm{oil}}=\frac{W_{\mathrm{oil}}}{W_s}\×100\%---\left(5\right);$

In same environmental system, the relative humidity in different states of matters is equal, the therefore relative humidity in air (RH_air) with insulating oil in relative humidity (RH_oil) be equal, i.e. RH_air=RH_oil, then formula (4) and (5) simultaneous obtain formula (6):

$P=P_s\·\frac{W_{\mathrm{oil}}}{W_s}---\left(6\right).$

Wherein, the saturated vapor pressure numerical tabular under different temperatures is as shown in table 1, utilizes the data in this table matching to obtain Saturated vapor pressure formula under different temperatures, as shown in formula (7):

$P_s={10}^{7.8825-\frac{2191.8}{273.15+T}}---\left(7\right).$

Saturated vapor pressure numerical tabular under table 1 different temperatures

Temperature (DEG C)	10	15	20	25	30	35	40
								Saturated water vapor pressure (kPa)	1.2262	1.7068	2.3346	3.1684	4.2474	5.6207	7.3766
Temperature (DEG C)	45	50	55	60	65	70	75
								Saturated water vapor pressure (kPa)	9.5837	12.340	15.743	19.923	25.014	31.164	38.554
Temperature (DEG C)	80	85	90	95	100
								Saturated water vapor pressure (kPa)	47.379	57.875	70.136	84.556	101.33

In order to obtain parameter A, B, c and n, the present invention utilizes testing equipment as shown in Figure 1 to test, particularly as follows:

(1) by dry insulating oil 6 (in insulating oil, moisture is less than 10ppm) and insulating paper 5, (in insulating paper, moisture contains Amount is less than 0.4%) it is placed in open glass bottle 4 according to the ratio mixing that mass ratio is 18:1, make 4 parts of identical samples, compile Number be respectively 1# sample 10,2# sample 11,3# sample 12,4# sample 13；Then by open glass bottle 4, it is placed in normal temperature environment Stand 72h, use the acid number in JKCS-3 automatic acid value tester test 1# sample 10 insulating oil；

(2) it is all placed in calorstat 7 being accelerated heat ageing by 2# sample 11,3# sample 12 and 4# sample 13；Calorstat 7 In temperature be set as 150 DEG C, temperature fluctuation amplitude is ± 0.5 DEG C；Take out 2# sample 11 after 15 days, use JKCS-3 automatic acid Acid number in value tester test insulating oil；Take out 3# sample 12 after 30 days, use the test of JKCS-3 automatic acid value tester absolutely Acid number in edge oil；Take out 4# sample 13 after 45 days, use the acid number in JKCS-3 automatic acid value tester test insulating oil；

(3) being placed in glass drying oven 1 by aqueous glycerol solution 2, perforated baffle 3 is placed in above glass drying oven 1, then will Glass drying oven 1 is placed in calorstat 7 together with perforated baffle 3, by 1# sample 10,2# sample 11,3# sample 12 and 4# sample 13 Open glass bottle 4 blow-by, be subsequently placed in above perforated baffle 3；

(4) the humiture monitor 9 outside by the Temperature Humidity Sensor 8 being placed in calorstat 7 and calorstat 7 is monitored in real time Temperature in calorstat 7 and relative humidity: the first temperature in regulating thermostatic case 7 is 10 DEG C, grasp according to ASTM D5032-2011 Make the relative humidity in code regulating thermostatic case 7, until moisture after insulating oil 6 and insulating paper 5 reach poised state, use moisture Content meter (915KF Ti-Touch body formula karl Fischer titrator) sporadically measures in insulating oil 6 and insulating paper 5 Moisture；Temperature in regulating thermostatic case 7 is 20 DEG C～100 DEG C (being spaced 10 DEG C) the most successively, treats that moisture is insulating oil 6 He After insulating paper 5 reaches poised state, sporadically measure the moisture in insulating oil 6 and insulating paper 5.

(5) insulating oil 6 and the insulating paper 5 of 4 parts of samples are dried process respectively so that moisture in insulating oil 6 Less than 10ppm, in insulating paper 5, moisture is less than 0.4%, and the temperature in regulating thermostatic case 7 is 10 DEG C, and relative humidity is 80%；When the humiture monitor 9 outside calorstat 7 shows that relative humidity is a constant numerical value, it is believed that in insulating oil 6 Moisture reaches saturated, uses corneometer (915KF Ti-Touch body formula karl Fischer titrator) to measure insulation Moisture in oil 6, this value is water saturation dissolubility in insulating oil；Then according to the method tests calorstat 7 respectively In temperature be water saturation dissolubility in the insulating oil 6 time 15 DEG C～100 DEG C (being spaced 5 DEG C).

By above test method, water saturation dissolubility in 4 parts of samples insulating oil at different temperatures can be obtained, As shown in table 2.

Water saturation dissolubility in insulating oil under table 2 different temperatures

Utilize method of least square that the data in table 2 are fitted according to formula (2), can obtain parameter A, parameter B and Parameter m, wherein, A=7.26, B=1618.3, m=0.9384；So formula (2) is:

$W_s=10^{7.26-\frac{1618.3}{279.15+T}+0.9384\×A_c}---\left(2\right);$

By above test method, can obtain 4 parts of samples under condition of different temperatures, moisture is at insulating paper and insulating oil Between when being in poised state, the moisture in insulating paper and insulating oil, as shown in table 3.

Moisture in insulating paper and insulating oil under table 3 different temperatures

Formula (6), formula (7) and formula (2) are substituted in formula (3), available formula (8):

$W_{\mathrm{paper}}=c{[{10}^{7.8825-\frac{2191.8}{273.15+T}}\×\frac{W_{\mathrm{oil}}}{{10}^{7.26-\frac{1618.3}{273.15+T}+0.9384\×A_c}}]}^n---\left(8\right);$

Data in table 3 are fitted by recycling method of least square according to formula (8), can obtain under various sample Parameter c and parameter n, then average, and i.e. can get parameter c and the value of parameter n under different temperatures, respectively such as table 4 and table 5 institute Show.

The value of parameter c under table 4 different temperatures

The value of parameter n under table 5 different temperatures

Matching the relation of parameter c and temperature T can be obtained, as shown in formula (9): c=16.59e according to the data in table 4^-0.0423×T(9)；Matching the relation of parameter n and temperature T can be obtained, as shown in formula (10): n=0.0058 according to the data in table 5 ×T+0.3478(10)；Formula (9) and formula (10) are substituted into formula (8), obtains insulating oil temperature (T, unit is: DEG C), absolutely Edge water content in oil content (W_oil, unit is: (Ac, unit is acid number: the oil immersed type in the case of mgKOH/g) ppm) and in insulating oil The computing formula of moisture in the aging insulating paper of transformator, such as formula (1):

$W_{\mathrm{paper}}=16.59e^{-0.0423\×T}{[{10}^{7.8825\frac{2191.8}{273.15+T}}\×\frac{W_{\mathrm{oil}}}{{10}^{7.26-\frac{1618.3}{273.15+T}+0.9384\×A_c}}]}^{0.0058\×T+0.3478}---\left(1\right).$

The preferred embodiment of the invention will be described in detail below.

Embodiment 1

Taking the insulating oil of oil-immersed power transformer in work, temperature T of the real time measure insulating oil is 70 DEG C；Take part (5ml) insulating oil measuring excess temperature is placed in 915KF Ti-Touch body formula karl Fischer titrator, measures wherein moisture Content W_oilFor 38.6ppm；The insulating oil taking part (5ml) mensuration excess temperature again is placed in JKCS-3 automatic acid value tester, surveys Measure its acid number A_cFor 0.068mgKOH/g.T=70 DEG C, W_oil=38.6ppm and A_c=0.068mgKOH/g substitutes into following formula In, try to achieve moisture in insulating paper:

$W_{\mathrm{paper}}=16.59e^{-0.0423\×T}{[{10}^{7.8825\frac{2191.8}{273.15+T}}\×\frac{W_{\mathrm{oil}}}{{10}^{7.26-\frac{1618.3}{273.15+T}+0.9384\×A_c}}]}^{0.0058\×T+0.3478}(\%)$

That is:

$W_{\mathrm{paper}}=16.59e^{-0.0423\×T}{[{10}^{7.8825\frac{219.8}{273.15+T}}\×\frac{38.6}{{10}^{7.26-\frac{1618.3}{273.15+T}+0.9384\×A_c}}]}^{00058\×70+0.3478}=1.995(\%)$

Therefore being tested the moisture obtained in this oil-filled transformer insulating paper is 1.955%.

Embodiment 2

Insulating oil temperature T testing certain oil-filled transformer is 82 DEG C, and this temperature, between 10 DEG C～100 DEG C, is then adopted Moisture W in insulating oil is measured with corneometer (915KF Ti-Touch body formula karl Fischer titrator)_oilFor 42.8ppm, uses JKCS-3 automatic acid value tester to measure acid number A in insulating oil_cFor 0.105mgKOH/g.T=82 DEG C, W_oil=42.8ppm and A_c=0.105mgKOH/g substitutes in following formula, tries to achieve moisture in insulating paper:

$W_{\mathrm{paper}}=16.59e^{-0.0423\×T}{[{10}^{7.8825\frac{2191.8}{273.15+T}}\×\frac{W_{\mathrm{oil}}}{{10}^{7.26-\frac{1618.3}{273.15+T}+0.9384\×A_c}}]}^{0.0058\×T+0.3478}(\%)$

That is:

$W_{\mathrm{paper}}=16.59e^{-0.0423\×82}{[{10}^{7.8825\frac{2191.8}{273.15+82}}\×\frac{42.8}{{10}^{7.26-\frac{1618.3}{273.15+82}+0.9384\×0.105}}]}^{0.0058\×82+0.3478}=1.441(\%)$

Therefore being tested the moisture obtained in this oil-filled transformer insulating paper is 1.441%.

Above-described embodiment, only for technology design and the feature of the explanation present invention, its object is to allow person skilled in the art Scholar will appreciate that present disclosure and implements according to this, can not limit the scope of the invention with this.All according to the present invention The equivalence that spirit is made changes or modifies, and all should contain within protection scope of the present invention.

Claims (3)

1. applying acid number and moisture in insulating oil to measure a method for moisture in insulating paper, it includes following successively Step:

A () takes the insulating oil of oil-immersed power transformer in work, temperature T of the real time measure insulating oil；

B () takes the insulating oil of part mensuration excess temperature and is placed in karl Fischer titrator, measure the content W of wherein moisture_oil；

C () takes the insulating oil of part mensuration excess temperature again and is placed in automatic acid value tester, measure its acid number A_c；

In d insulating oil that () is aging, in water saturation dissolubility and insulating oil temperature, insulating oil, the relation of acid number meets formula (1):

(1)；

In formula, W_sBeing water saturation dissolubility in insulating oil, unit is ppm；T is the temperature of insulating oil, and unit is DEG C；A and B is Coefficient of association, constituent with insulating oil, chemical property etc. are relevant；M is the shift factor relevant to acid number in insulating oil；Oil Paper insulation system is adsorbed the moisture in insulating paper and can meet formula (2):

(2)；

In formula, W_paperIt is the content of moisture in insulating paper, represents by weight/mass percentage composition or mass percent (%)；C is that absorption is flat Weighing apparatus constant, typically reduces with the rising of temperature；N is to characterize the parameter that material absorption property is strong and weak；P be water vapour in the gas phase Equilibrium partial pressure, unit is kPa；

Utilize formula (1) and formula (2) to shift onto obtain formula (3), calculate the weight/mass percentage composition W of moisture in insulating paper_paper ,

(3)；

It is characterized in that, in formula (1) and formula (2), parameter A, the testing process of B, c and n comprise the following steps:

(x1) dry insulating oil and insulating paper are placed in open glass bottle according to the ratio mixing that mass ratio is 18:1, make 4 parts of identical samples, numbering is respectively 1# sample, 2# sample, 3# sample, 4# sample；Then by open glass bottle, it is placed in room temperature Environment stands 72h, uses the acid number in JKCS-3 automatic acid value tester test 1# sample insulating oil；

(x2) 2# sample, 3# sample and 4# sample are all placed in calorstat being accelerated heat ageing；Temperature in calorstat sets Being set to 150 DEG C, temperature fluctuation amplitude is ± 0.5 DEG C；Take out 2# sample after 15 days, use the test of JKCS-3 automatic acid value tester Acid number in insulating oil；Take out 3# sample after 30 days, use the acid number in JKCS-3 automatic acid value tester test insulating oil；45 Take out 4# sample after it, use the acid number in JKCS-3 automatic acid value tester test insulating oil；

(x3) being placed in glass drying oven by aqueous glycerol solution, perforated baffle is placed in above glass drying oven, then by vierics Ware is placed in calorstat together with perforated baffle, by the closeest for the open glass bottle of 1# sample, 2# sample, 3# sample and 4# sample Envelope, is subsequently placed in above perforated baffle；

(x4) calorstat monitored in real time by the humiture monitor outside by the Temperature Humidity Sensor being placed in calorstat and calorstat In temperature and relative humidity: the first temperature in regulating thermostatic case is 10 DEG C, and the relative humidity in regulating thermostatic case treats moisture After insulating oil and insulating paper reach poised state, corneometer is used sporadically to measure in insulating oil and insulating paper Moisture；Temperature in regulating thermostatic case is 20 DEG C ~ 100 DEG C the most successively, is spaced 10 DEG C of regulating thermostatic casees once, treats water Divide after insulating oil and insulating paper reach poised state, sporadically measure the moisture in insulating oil and insulating paper；

(x5) insulating oil and the insulating paper of 4 parts of samples are dried process respectively so that in insulating oil, moisture is less than 10ppm, in insulating paper, moisture is less than 0.4%, and the temperature in regulating thermostatic case is 10 DEG C, and relative humidity is 80%；Work as constant temperature When humiture monitor display relative humidity outside case is a constant numerical value, the moisture in insulating oil reaches saturated, Using corneometer to measure the moisture in insulating oil, this value is water saturation dissolubility in insulating oil；Then The temperature repeating to test in calorstat respectively is water saturation dissolubility in insulating oil when 15 DEG C ~ 100 DEG C, is spaced 5 DEG C of tests Once.

The assay method of moisture in insulating paper the most according to claim 1, it is characterised in that: described temperature T is 10 ℃~100℃。

The assay method of moisture in insulating paper the most according to claim 1, it is characterised in that: step (b) and step C, in (), the amount of taking of described insulating oil is 1 ~ 10 milliliter.