CN106645531B - A kind of modification method of Gases Dissolved in Transformer Oil detection data - Google Patents

Abstract

The invention relates to a method for correcting detection data of dissolved gas in transformer oil, which comprises the following steps: (1) selecting a sample of transformer oil when the transformer is in normal operation as a normal oil sample, and selecting a sample of transformer oil when the transformer is faulty as a fault (2) Use the normal oil standard gas and faulty oil standard gas prepared in step (1), and use the gas chromatograph to calibrate respectively in accordance with the national standard GB/T17623‑1998 with the external calibration method; ( 3) Detect the transformer oil to be tested, measure the peak area of each gas component from the chromatogram, (4) determine the concentration of each gas component in the outgas of the transformer oil sample to be tested, (5) determine the concentration of each gas component in the transformer oil sample to be tested The content of each gas component in the sample, the accuracy of the result of the invention is high, and the content of various dissolved gases in the transformer oil can be tested.

Description

A Correction Method for Detection Data of Dissolved Gas in Transformer Oil

technical field

The invention relates to a method for correcting detection data of dissolved gas in transformer oil.

Background technique

Transformer is one of the important electrical equipment in power system, once it breaks down, it will bring serious consequences. The content analysis of dissolved gas components in transformer oil is the most effective means to monitor the operation status of transformers at home and abroad, so the accuracy of the content data of dissolved gas components in transformer oil directly determines the accuracy of transformer state evaluation.

Gas chromatography is commonly used in the analysis of dissolved gas components in transformer oil. First, the oil samples in the transformer are collected, and then the dissolved gases in the oil are extracted, and then the gas chromatograph is used to separate and detect the content of each component in the extracted gas. Through the data The concentration of each dissolved gas component in the oil is calculated. In the process of sample analysis, the gas chromatograph used needs to be calibrated first. The standard gas external standard method is adopted in the existing standard, that is, a standard mixed gas with known concentration of each component is used to calibrate the instrument before each test. Measure the peak area or peak height of each component from the obtained chromatogram to calculate the result of subsequent sample analysis. There is only one standard mixed gas concentration used in this method, and the concentration of the gas components in the sample to be tested is variable, which leads to the fact that the single-concentration standard mixed gas external standard method cannot be well applied to the oil samples to be tested in various concentration ranges. The problem. Therefore, a better calibration and data calculation method is needed.

Contents of the invention

The purpose of the present invention is to provide a method for correcting the detection data of dissolved gas in transformer oil. Before the test, samples of transformer oil during normal operation and failure of the transformer are respectively selected, and standard gas is made according to the type and concentration of characteristic gas. The gas chromatograph is calibrated at two points, and then the gas chromatogram data of the transformer oil sample to be tested is calculated by interpolation to obtain the content of each gas component in the transformer oil sample to be tested. The content of dissolved gases was tested.

In order to achieve the above purpose, the following steps are included: (1) Preparation of standard gas: select the sample of transformer oil when the transformer is in normal operation, which is the normal oil sample, and select the sample of transformer oil when the transformer is faulty, which is the faulty oil sample, respectively press normal oil The gas concentration dissolved in the sample and the faulty oil sample is prepared as a standard gas. The concentration of each component in the normal oil standard gas is c _is1 , and the concentration of each component in the faulty oil standard gas is c _is2 ;

Where: c _is1 —concentration of component i in normal oil standard gas, uL/L;

c _is2 —concentration of component i in the faulty oil standard gas, uL/L;

(2) Determine the peak area of the standard gas: Use the normal oil standard gas and faulty oil standard gas prepared in step (1), and use the gas chromatograph to calibrate respectively according to the external standard quantitative method in the national standard GB/T17623-1998, and then measure them respectively Take the peak area of each gas component, the peak area of each gas component in the normal oil standard gas is _Ais1 , and the peak area of each gas component in the faulty oil standard is _Ais2 , repeat the operation twice under the condition of stable instrument working conditions , the repeatability is within ±2% of the average value, and the average value is taken , ;

Among them, _Ais1 —the peak area of component i in normal oil standard gas, mm ² ;

_Ais2 —the peak area of component i in the faulty oil standard gas, mm ² ;

—the average peak area of component i in normal oil standard gas, mm ² ;

—The average peak area of component i in the trouble oil standard gas, mm ² ;

(3) Test the transformer oil to be tested: According to the national standard GB/T17623-1998, the sample of the transformer oil to be tested is degassed by mechanical oscillation method, and the released gas is analyzed by gas chromatography to obtain a chromatogram, and from the chromatogram The peak area A _i of each gas component is measured in the figure, the parallel samples are tested twice, and the arithmetic mean of the peak area of each gas component is taken ;

Among them, A _i —the peak area of component i in the transformer oil sample to be tested, mm ² ;

- the average peak area of component i in the transformer oil sample to be tested, mm ² ;

(4) Determine the concentration of each gas component in the outgas of the transformer oil sample to be tested: According to the parameters obtained in steps (1)-(3), calculate the concentration of the gas out of the transformer oil sample to be tested according to the following formula (1): The concentration of each gas component:

(1)

Where: c _i —concentration of component i in the gas released from the transformer oil sample to be tested, uL/L;

(5) Determine the content of each gas component in the transformer oil sample to be tested: According to the parameters obtained in step (4), calculate the dissolved gases in the transformer oil sample to be tested according to the following formulas (2)-(4) The content of components X _i :

Where: X _i — gas concentration of component i dissolved in the transformer oil sample to be tested, uL/L;

P - Atmospheric pressure during detection, kPa;

Distribution coefficient of dissolved gas i component in domestic mineral insulating oil at K _i -50°C;

V _g ′——50℃, equilibrium gas volume under test pressure, mL;

V _l ′—the volume of the transformer sample to be tested extracted at 50°C, mL;

t—room temperature during detection, °C;

V _g —balanced gas volume at room temperature t and detection pressure, mL;

V _l - the volume of the transformer sample to be tested extracted at room temperature t, mL;

Preferably, in step (1), entrust the normal oil sample and faulty oil sample to an institution with national standard gas preparation qualifications to prepare standard gas according to the characteristic gas types and concentrations dissolved in the normal oil sample and faulty oil sample respectively.

Preferably, the components of the normal oil standard gas are hydrogen c _H2s1 150 μL/L, acetylene c _C2H2s1 1 μL/L, methane c _CH4s1 20 μL/L, ethylene c _C2H4s1 10 μL/L, ethane c _C2H6s1 10 μL/L, Carbon monoxide c _COs1 1000 μL/L and carbon dioxide c _CO2s1 300 μL/L, the components of the fault oil standard gas are hydrogen c _H2s2 750 μL/L, acetylene c _C2H2s2 5 μL/L, methane c _CH4s2 100 μL/L, ethylene c _C2H4s2 50 μL/L L. Ethane c _C2H6s2 50 μL/L, carbon monoxide c _COs2 4000 μL/L, carbon dioxide c _CO2s2 1000 μL/L.

Preferably, the gas chromatograph in the step (2) should be certified by the national metrology institution and within the validity period.

The positive effect of the present invention is as follows:

The invention discloses a method for correcting the detection data of dissolved gas in transformer oil. Before the test, samples of transformer oil during normal operation and failure of the transformer are respectively selected, and standard gas is made according to the type and concentration of the characteristic gas in the transformer oil. The instrument is calibrated at two points, and then the gas chromatogram data of the transformer oil sample to be tested is calculated by the interpolation method to obtain the content of each gas component in the transformer oil sample to be tested, which solves the problem of the single concentration standard mixed gas external standard in the prior art. The method cannot be well applied to the problem of oil samples to be tested in various gas concentration ranges.

The present invention uses standard gas of normal oil standard gas and standard gas of faulty oil to calibrate the gas chromatograph at two points, and then calculates the gas chromatogram data of the outgassed transformer oil sample by interpolation method (1) The concentration of each gas component is obtained, and finally the content of each gas component in the transformer oil sample to be tested is obtained by using formulas (2)-(4). Point calibration and proportional calculation have wider sample applicability, and the calculation accuracy of the detection data of unknown concentration samples has been effectively improved.

The method of the invention is accurate in detection and convenient in use. It is suitable for online detection of dissolved gas in transformer oil.

Detailed ways

Embodiments of the present invention will be further described in detail below.

In this embodiment, a certain transformer oil sample of Hebei power grid is evaluated, and the specific implementation is as follows:

(1) Preparation of standard gas: select the sample of transformer oil when the transformer is in normal operation, as the normal oil sample, and select the sample of transformer oil when the transformer is faulty, as the faulty oil sample, according to the dissolved gas in the normal oil sample and the faulty oil sample respectively The concentration of each component in the normal oil standard gas is c _is1 , and the concentration of each component in the faulty oil standard gas is c _is2 ; the normal oil sample and the faulty oil sample are entrusted to a company with national standard gas preparation qualifications The agency prepares standard gas according to the type and concentration of the characteristic gas dissolved in the normal oil sample and the faulty oil sample respectively;

Where: c _is1 —concentration of component i in normal oil standard gas, uL/L;

c _is2 —concentration of component i in the faulty oil standard gas, uL/L;

In the normal oil standard gas in this example: hydrogen c _H2s1 150 μL/L, acetylene c _C2H2s1 1 μL/L, methane c _CH4s1 20 μL/L, ethylene c _C2H4s1 10 μL/L, ethane c _C2H6s1 10 μL/L, carbon monoxide c _COs1 1000 μL /L and carbon dioxide c _CO2s1 300μL/L.

The concentration of each component in the fault oil standard gas is: hydrogen c _H2s2 750 μL/L, acetylene c _C2H2s2 5 μL/L, methane c _CH4s2 100 μL/L, ethylene c _C2H4s2 50 μL/L, ethane c _C2H6s2 50 μL/L, carbon monoxide c _COs2 4000μL/L, carbon dioxide cCO2s2 _1000μL /L.

(2) Determine the peak area of the standard gas: Use the normal oil standard gas and faulty oil standard gas prepared in step (1), and use the gas chromatograph to calibrate respectively according to the external standard quantitative method in the national standard GB/T17623-1998. The gas chromatograph should be verified by the national metrology institution and within the validity period, and then measure the peak area of each gas component respectively. The peak area of each gas component in normal oil standard gas is A _is1 , and the peak area of each gas component in faulty oil standard The area is A _is2 , the operation is repeated twice under the condition of stable instrument conditions, the repeatability is within ±2% of the average value, and the average value is taken , ;

Among them, _Ais1 —the peak area of component i in normal oil standard gas, mm ² ;

_Ais2 —the peak area of component i in the faulty oil standard gas, mm ² ;

—the average peak area of component i in normal oil standard gas, mm ² ;

—The average peak area of component i in the trouble oil standard gas, mm ² ;

In this embodiment, the peak area of each gas component on the spectrum is obtained according to the method of step (2).

In normal oil standard gas: Repeat the operation twice under the condition of stable instrument working conditions, satisfying that the repeatability is within ±2% of the average value, and the average value is hydrogen 1867mm ² , Acetylene 1159mm ² 、methane 12423mm ² , Vinyl 11959mm ² , ethane 11851mm ² 、Carbon monoxide 65055mm ² , carbon dioxide 36590mm ² .

In the faulty oil standard gas: repeat the operation twice under the condition of stable instrument working conditions, satisfying the repeatability within ±2% of the average value, the average value is hydrogen 9338mm ² , Acetylene 5795mm ² 、methane 62118mm ² , Vinyl 59796mm ² , ethane 255mm ² , carbon monoxide 260220mm ² , carbon dioxide 121969mm ² .

(3) Test the transformer oil to be tested: According to the national standard GB/T17623-1998, the sample of the transformer oil to be tested is degassed by mechanical oscillation method, and the released gas is analyzed by gas chromatography to obtain a chromatogram, and from the chromatogram The peak area A _i of each gas component is measured in the figure, the parallel samples are tested twice, and the arithmetic mean of the peak area of each gas component is taken ;

Among them, A _i —the peak area of component i in the transformer oil sample to be tested, mm ² ;

- the average peak area of component i in the transformer oil sample to be tested, mm ² ;

In this embodiment, the environmental conditions when testing the transformer oil sample to be tested are: P = 101.3 kPa, t = 20°C. V _l =40 mL, V _g =3.0 mL, measure the peak area of each gas component from the chromatogram, and obtain the peak area of each component in the gas chromatogram released from the transformer oil sample to be tested: hydrogen 334mm ² , Acetylene 20mm ² , methane 84958mm ² , Vinyl 4534mm ² , ethane 119717mm ² 、Carbon monoxide 175980 mm ² , carbon dioxide 112101mm ² .

(4) Determine the concentration of each gas component in the outgas of the transformer oil sample to be tested: According to the parameters obtained in steps (1)-(3), calculate the concentration of the gas out of the transformer oil sample to be tested according to the following formula (1): The concentration of each gas component:

(1)

Where: c _i —concentration of component i in the gas released from the transformer oil sample to be tested, uL/L;

In this embodiment, take the hydrogen component as an example:

;

The calculation method of other components is the same as that of hydrogen, and the corresponding parameters can be brought into the formula (1), and they will not be listed here.

(5) Determine the content of each gas component in the transformer oil sample to be tested: According to the parameters obtained in step (4), calculate the dissolved gases in the transformer oil sample to be tested according to the following formulas (2)-(4) The content of components X _i :

Where: X _i — gas concentration of component i dissolved in the transformer oil sample to be tested, uL/L;

P - Atmospheric pressure during detection, kPa;

The distribution coefficient of the dissolved gas i component in the domestic mineral insulating oil at K _i -50°C, this parameter is listed in GB/T17623-1998, and can be obtained by referring to the corresponding list;

V _g ′——50℃, equilibrium gas volume under test pressure, mL;

V _l ′—the volume of the transformer sample to be tested extracted at 50°C, mL;

t—room temperature during detection, °C;

V _g —balanced gas volume at room temperature t and detection pressure, mL;

V _l - the volume of the transformer sample to be tested extracted at room temperature t, mL;

The environmental conditions for testing the transformer oil samples to be tested are: P = 101.3 kPa, t = 20°C. _Vl =40mL, _Vg =3.0mL;

Taking hydrogen as an example, it is calculated that:

.

The calculation method of other components in this example is the same as that of hydrogen, and the concentration of each gas component in the transformer oil sample to be tested can be calculated according to formulas (2)-(4): hydrogen 3.52 μL/L, acetylene 0.02 μL/L, methane 59.81 μL/L, ethylene 5.43 μL/L, ethane 223.42 μL/L, carbon monoxide 504.47 μL/L and carbon dioxide 854.47 μL/L.

The above description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the patented invention. Therefore, the present invention will not be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (3)

1. a kind of modification method of Gases Dissolved in Transformer Oil detection data, it is characterised in that：Include the following steps,

(1) preparation of calibrating gas：The sample of transformer oil when choosing transformer normal operation is normal oil sample sheet, chooses and become The sample of transformer oil when depressor failure is failure oil sample sheet, presses the gas dissolved in normal oil sample sheet and failure oil sample sheet respectively Bulk concentration is configured to calibrating gas, a concentration of c of each component in normal oil standard gas_is1, each component in failure oil standard gas A concentration of c_is2；

Wherein：c_is1The concentration of i components, μ L/L in-normal oil standard gas；

c_is2The concentration of i components, μ L/L in-failure oil standard gas；

The group of the normal oil standard gas is divided into hydrogen c_H2s1150 μ L/L, acetylene c_C2H2s11 μ L/L, methane c_CH4s120μL/L、 Ethylene c_C2H4s110 μ L/L, ethane c_C2H6s110 μ L/L, carbon monoxide c_COs11000 μ L/L and carbon dioxide c_CO2s1300 μ L/L, institute The group for stating failure oil standard gas is divided into hydrogen c_H2s2750 μ L/L, acetylene c_C2H2s25 μ L/L, methane c_CH4s2100 μ L/L, ethylene c_C2H4s250 μ L/L, ethane c_C2H6s250 μ L/L, carbon monoxide c_COs24000 μ L/L, carbon dioxide c_CO2s21000μL/L；

(2) peak area of calibrating gas is determined：The normal oil standard gas and failure oil standard gas prepared using step (1), Outer marking quantitative method is demarcated respectively using gas chromatograph in GB/T17623-1998 according to national standards, is then measured respectively Each gas component peak area, the peak area of each gas component is A in normal oil standard gas_is1, each gas component of failure oil standard Peak area be A_is2, twice, repeatability takes within ± the 2% of average value for repetitive operation under conditions of instrument stable conditions Its average value

Wherein, A_is1The peak area of i components, mm in-normal oil standard gas²；

A_is2The peak area of i components, mm in-failure oil standard gas²；

The average peak area of i components, mm in-normal oil standard gas²；

The average peak area of i components, mm in-failure oil standard gas²；

(3) transformer oil to be measured is detected：GB/T17623-1998 according to national standards, using mechanical oscillation method to be measured The sample of transformer oil is de-gassed, and is analyzed abjection gas using gas chromatograph, is obtained chromatogram, and from chromatogram The middle peak area A for measuring each gas component_i, parallel sample detect twice, take each gas component peak area arithmetic mean of instantaneous value

Wherein, A_iThe peak area of i components, mm in-transformer oil sample to be measured²；

The average peak area of i components, mm in-transformer oil sample to be measured²；

(4) concentration of each gas component in transformer oil sample pint outlet to be measured is determined：The ginseng obtained according to step (1)-(3) Number, (1) calculates the concentration of each gas component in transformer oil sample pint outlet to be measured according to the following equation：

Wherein：c_iI concentration of component in-transformer oil sample pint outlet to be measured, μ L/L；

(5) content of each gas component in transformer oil sample to be measured is determined：According to the parameter that step (4) obtains, according to following Formula (2)-(4) calculate the content X of each gas component dissolved in transformer oil sample to be measured_i：

V′_l=V_l[1+0·0008×(50-t)] (4)

Wherein：X_iThe gas concentration of the i components dissolved in-transformer oil sample to be measured, μ L/L；

Atmospheric pressure when P-detection, kPa；

K_iThe distribution coefficient of domestic mineral insulation oil dissolved gas i components at -50 DEG C；

V_gBalanced gas volume, mL under ' -50 DEG C, test pressure；

V_lThe volume of the transformer sample to be measured extracted when ' -50 DEG C, mL；

Room temperature when t-detection, DEG C；

V_gBalanced gas volume under-room temperature t, detection pressure, mL；

V_lThe volume of the transformer sample to be measured extracted when-room temperature t, mL.

2. a kind of modification method of Gases Dissolved in Transformer Oil detection data according to claim 1, it is characterised in that： In step (1), the mechanism that normal oil sample sheet and this commission of failure oil sample are prepared to qualification with national standard gas is pressed just respectively The characteristic gas type and concentration dissolved in normal oil sample sheet and failure oil sample sheet is configured to calibrating gas.

3. a kind of modification method of Gases Dissolved in Transformer Oil detection data according to claim 1, it is characterised in that： Gas chromatograph in the step (2) should pass through national measurement mechanism and examine and determine and before the deadline.