CN115421013A - Insulation damping and aging evaluation method for inverted current transformer - Google Patents
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- 238000009413 insulation Methods 0.000 title claims abstract description 52
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Abstract
The invention discloses an insulation damp and aging evaluation method for an inverted current transformer, which belongs to the technical field of power equipment insulation state evaluation and comprises the steps of obtaining imaginary part and real part basic data of composite dielectric constants of oil-impregnated paper with different water contents and different aging degrees, correcting the influence of water phase state change on dielectric parameters, establishing a dielectric parameter characteristic frequency band only influenced by the aging degree, carrying out frequency Wen Fanxiang translation on a main dielectric parameter curve, respectively carrying out fitting calculation on the characteristic frequency band influenced by the moisture and the characteristic frequency band influenced by the aging in an actually measured loss factor curve through a theoretical calculation expression of a total capacitance CA of the current transformer, and obtaining the moisture content and the polymerization degree when the fitting goodness of the curve is less than or equal to 3%. A direct measuring and calculating method is provided for the difference evaluation of the inverted current transformer distinguishing the insulation aging or damp state under wide temperature.
Description
Technical Field
The invention belongs to the technical field of insulation state evaluation of power equipment, and particularly relates to an insulation damp and aging evaluation method of an inverted current transformer.
Background
The inverted current transformer is easy to have insulation defects in terms of product manufacturing process, compared with a power transformer, although the inverted current transformer is oil paper insulation power equipment, oil paper insulation of the power transformer is concentrated in a narrow inner space of a porcelain sleeve, an oil paper insulation interlayer structure of the inverted current transformer has the characteristics of large capacitance and thick insulation, and the insulation structure and the oil paper ratio have great difference with the transformer. During production, the winding process of the insulating part of the transformer is difficult to control in the manufacturing process, the electric field distribution is uneven due to the fact that pits appear in the winding process or insulating paper is wrinkled due to the fact that the winding process is loose and soft, local field intensity is too high, partial discharge can be caused when the local field intensity is serious, and fault hidden danger in the operation of the transformer is formed; meanwhile, the chain breakage of insulating material molecules is caused by the insulating aging effect of the oil paper, and the formed low-molecular products can generate a large amount of moisture and accelerate the aging process, so that the normal operation of the mutual inductor is seriously influenced, and the safe operation of a power grid is threatened to a certain extent.
Most of the existing field tests of the mutual inductor are high-voltage power frequency performance tests (10 kV and 50 Hz), the tests have certain damage, especially the pressure-resistant cumulative effect, and can also have certain influence on the oil paper insulation of the mutual inductor, and particularly when water is analyzed at low temperature, the tests under high voltage can also cause the faults of insulating creepage, abnormal discharge breakdown and the like.
When the traditional inverted current transformer is used for insulation state evaluation, a high-voltage bridge balance method is adopted, but the information quantity of measurement data under single frequency is small, exact information of potential problems of a measured object cannot be given, and differences of insulation aging or damp states cannot be distinguished. The change rule of the insulating dielectric property of the oil paper at low temperature is greatly different from the evaluation at normal temperature, a single temperature equivalent translation method is not suitable at low temperature, the current tests on the water content and the aging polymerization degree of the main insulating paper still need to disassemble a mutual inductor to take a paper sample for chemical titration analysis and measurement, the detection and evaluation cost is high due to the complex operation, and the diagnosis requirements of high and cold low-temperature construction and commissioning and equipment running states in China cannot be met.
Therefore, there is a need in the art for a new solution to solve this problem.
Disclosure of Invention
In order to overcome the defects in the prior art, the invention provides an insulation wetting and aging evaluation method for an inverted current transformer, which is used for solving the problems that the difference of insulation aging or wetting states cannot be distinguished and the insulation state of the inverted current transformer cannot be accurately evaluated at high and cold low temperatures.
In order to achieve the purpose, the invention adopts the technical scheme that: an insulation damp and aging evaluation method for an inverted current transformer comprises the following steps which are sequentially carried out,
firstly, performing frequency domain dielectric response test on oil-impregnated paper with different water contents and different aging degrees through a frequency domain dielectric response test system at different test temperatures to obtain imaginary part and real part basic data of a complex dielectric constant;
step two, constructing a dielectric parameter representation method of the oil-impregnated paper-water composite dielectric system in temperature regions above zero DEG C and below zero DEG C respectively according to dielectric response data of the oil-impregnated paper base with different water contents obtained by the test in the step one, and correcting the influence of the phase state change of water on the dielectric parameters;
step three, carrying out comparative analysis on the oil-impregnated paper basic dielectric response data with different aging degrees obtained by the test in the step one, and establishing a dielectric parameter characteristic frequency band only affected by the aging degree for distinguishing the influence of moisture and aging on the oil-impregnated paper basic dielectric response data;
step four, calculating the total capacitance CA from the I main screen to the Λ main screen in the inverted current transformer according to the voltage grade and size of the current transformer;
step five, obtaining a frequency spectrum loss factor curve of the actually tested inverted current transformer at a certain testing temperature, and performing frequency Wen Fanxiang translation on the main dielectric parameter curve to obtain oil-impregnated paper basic dielectric data at the temperature, wherein the basic dielectric data is a complex dielectric constant;
step six, combining the dielectric parameter representation method of the oil impregnated paper-moisture composite medium system constructed in the step two, fitting and calculating the characteristic frequency band affected by moisture in the actually measured loss factor curve through a theoretical calculation expression of the total capacitance CA of the current transformer in the step four, and obtaining the moisture content of the oil impregnated paper in the main insulation when the fitting goodness of the curve is less than or equal to 3%;
and step seven, combining the aging basic data in the step three, fitting and calculating the characteristic frequency band affected by aging in the actually measured loss factor curve through a theoretical calculation expression of the total capacitance CA of the current transformer in the step four, and obtaining the polymerization degree of the oil-impregnated paper in the main insulation when the goodness of fit of the curve is less than or equal to 3%.
And in the fourth step, the total capacitance C from the I main screen to the Λ main screen in the inverted current transformer A Is obtained by the following steps of,
(1) calculating the main insulating capacitor C at the upper part of the inverted current transformer according to the voltage grade and the size of the current transformer T Equivalent to an eccentric ring capacitor C P An outer cylinder capacitor C W And an inner cylinder capacitor C L The calculation expression of each capacitance is as follows:
C T ＝C P +C W +C L (2)
in the formula, epsilon is the complex dielectric constant of the oil-impregnated paper; epsilon 0 8.854 × 10 as the vacuum dielectric constant -12 Fa/m; r is a radical of hydrogen x(Λ) Radius of the Λ main screen equivalent circle, unit: millimeter; r is x(Ι) The radius of the main screen is I outside the secondary winding of the ring part, and the unit is as follows: millimeter; d (Λ-Ι) The eccentric distance between the lambda main screen and the I main screen is represented by the following unit: millimeter; r x(Ι) The distance from the eccentric circle center of the I main screen to the center of the busbar is represented by the unit: millimeter; r x(Λ) Is ΛDistance from eccentric center of circle of main screen to center of bus bar, unit: millimeter; r is w(Λ) For the distance, the unit of lambda main screen eccentric circle outside to female arranging the center: millimeter; h L Inner cylinder thickness, unit: millimeter; h w Is the outer cylinder thickness, unit: millimeter;
(2) according to the structural size of the current transformer, the lead capacitor C is arranged n Calculating to obtain a capacitance C without end screen segment m And end screen section capacitor C d Performing calculation with no end-segment capacitance C m The calculation can be performed using concentric cylindrical capacitors:
in the formula, epsilon is the complex dielectric constant of the oil-impregnated paper; epsilon 0 8.854 × 10 as the vacuum dielectric constant -12 Fa/m; r is Λ For lead wire section department the lambda main screen equivalent radius, unit: millimeter; r is i Is the ith end screen equivalent radius at the lead section, unit: millimeter; l is (Λ) For Λ main screen no-end screen length, unit: millimeter;
capacitor C with end screen section d The calculation can be carried out according to the number of the end screens, and the expression is calculated by the main capacitor of the ith end screen section:
wherein epsilon is the complex dielectric constant of the oil-impregnated paper; epsilon 0 8.854 × 10 as the vacuum dielectric constant -12 Fa/m; l is a radical of an alcohol d Length of end screen, unit: millimeter; Δ L is the screen step difference at each end, unit: millimeter; delta. For the preparation of a coating d Insulation thickness between end screens, unit: millimeter;
therefore, the lead capacitor C of the current transformer with n end screens between the kth main screen and the k-1 main screen kn Can be expressed as:
in the formula, n is the number of end screens, unit: a plurality of;
(3) total capacitance C from the first I main screen to the Λ main screen in the inverted current transformer A Can represent the upper main insulation capacitance C T And lead wire capacitance C kn The parallel calculation of (a) is performed,
performing frequency Wen Pingyi reduction on the basic dielectric parameters of the oil-impregnated paper in different temperature regions as shown in the formula (7) to obtain a basic data main curve, and performing frequency-temperature reverse translation reduction in an actual test to obtain basic oil-impregnated paper dielectric response data at an actual test temperature as shown in the formula (8);
in the formula (f) T For the frequency required to translate to the T temperature, the unit: hertz; f. of 0 To test frequency, unit: hertz; t is the temperature of the desired translation, in units: kelvin; t is 0 To test temperature, unit: kelvin; Δ E (τ) is the relaxation activation energy of oil-impregnated paperboard in units: kilojoules per mole; k is Boltzmann constant, and has a size of 1.38 × 10 -23 Joule/kelvin.
Through the design scheme, the invention can bring the following beneficial effects:
1. a direct measuring and calculating method is provided for the difference evaluation of the inverted current transformer for distinguishing the insulation aging or damp state.
2. The influence of temperature on the viscosity of transformer oil and the influence of the phase state change of moisture on the dielectric parameters of the oil-immersed paper are fully considered, the method can be applied in a wide temperature range, and the requirements of environmental temperature in domestic and foreign tests are met.
Drawings
Fig. 1 is a flow chart of an insulation wetting and aging evaluation method of an inverted current transformer according to the present invention.
Fig. 2 is a schematic diagram of the upper part and the lead end of the inverted current transformer in the method for evaluating the insulation, moisture and aging of the inverted current transformer according to the present invention.
Fig. 3 is a testing wiring diagram of the insulation wetting and aging evaluation method of the inverted current transformer.
Fig. 4 is a frequency domain dielectric response loss factor curve diagram of the inverted current transformer at different temperatures in the embodiment of the insulation wetting and aging evaluation method of the inverted current transformer.
Fig. 5 is a fitting calculation curve diagram of the frequency domain dielectric response loss factor calculated by the method according to the actual measurement curve in the embodiment of the insulation wetting and aging evaluation method of the inverted current transformer.
Detailed Description
The following detailed description of the embodiments of the invention is provided in connection with the accompanying drawings
In order to more clearly illustrate the present invention, the present invention is further described below in conjunction with preferred embodiments. As will be appreciated by those skilled in the art. The following detailed description is to be construed as illustrative and not restrictive, and various changes may be made in the following parameters by a user without departing from the spirit and scope of the invention as set forth in the appended claims. Well-known methods and procedures have not been described in detail so as not to obscure the present invention.
Shown in figures 1-5: an insulation damp and aging evaluation method for an inverted current transformer comprises the following steps which are sequentially carried out,
the method comprises the following steps that firstly, frequency domain dielectric response testing is carried out on oil-impregnated paper with different water contents and different aging degrees through a frequency domain dielectric response testing system at different testing temperatures, and imaginary part and real part basic data of a complex dielectric constant are obtained;
step two, constructing a dielectric parameter representation method of the oil-impregnated paper-water composite dielectric system in temperature regions above zero DEG C and below zero DEG C respectively according to the dielectric response data of the oil-impregnated paper base with different water contents obtained by the test in the step one, and correcting the influence of the phase state change of water on the dielectric parameters;
step three, carrying out comparative analysis on the oil-impregnated paper basic dielectric response data with different aging degrees obtained by the test in the step one, and establishing a dielectric parameter characteristic frequency band only affected by the aging degree for distinguishing the influence of moisture and aging on the oil-impregnated paper basic dielectric response data;
step four, calculating the total capacitance CA from the I main screen to the Λ main screen in the inverted current transformer according to the voltage grade and size of the current transformer;
step five, obtaining a frequency spectrum loss factor curve of the actually tested inverted current transformer at a certain testing temperature, and performing frequency Wen Fanxiang translation on the main dielectric parameter curve to obtain oil-impregnated paper basic dielectric data at the temperature, wherein the basic dielectric data is a complex dielectric constant;
step six, combining the dielectric parameter expression method of the oil-impregnated paper-water composite medium system constructed in the step two, fitting and calculating the characteristic frequency band influenced by water in the actually measured loss factor curve through the theoretical calculation expression of the total capacitance CA of the current transformer in the step four, and obtaining the water content of the oil-impregnated paper in the main insulation when the fitting goodness of the curve is less than or equal to 3%;
and step seven, combining the aging basic data in the step three, fitting and calculating the characteristic frequency band affected by aging in the actually measured loss factor curve through a theoretical calculation expression of the total capacitance CA of the current transformer in the step four, and obtaining the polymerization degree of the oil-impregnated paper in the main insulation when the goodness of fit of the curve is less than or equal to 3%.
And in the fourth step, the total capacitance C from the I main screen to the Λ main screen in the inverted current transformer A Is obtained by the following steps of,
(1) calculating the upper main insulation of the inverted current transformer according to the voltage grade and size of the current transformerCapacitor C T Equivalent to an eccentric ring capacitor C P Outer cylinder capacitor C W And an inner cylinder capacitor C L The calculation expression of each capacitance is as follows:
C T ＝C P +C W +C L (2)
wherein epsilon is the complex dielectric constant of the oil-impregnated paper; epsilon 0 8.854 × 10 as the vacuum dielectric constant -12 Fa/m; r is x(Λ) Radius of the Λ main screen equivalent circle, unit: millimeter; r is x(Ι) The radius of the main screen is I outside the secondary winding of the ring part, and the unit is as follows: millimeter; d is a radical of (Λ-Ι) The unit is the eccentric distance between the lambda main screen and the I main screen: millimeter; r x(Ι) The distance from the eccentric circle center of the I main screen to the center of the busbar is represented by the unit: millimeter; r is x(Λ) For the eccentric centre of a circle of lambda main screen to the distance at female row center, the unit: millimeter; r w(Λ) For the distance, the unit of lambda main screen eccentric circle outside to female arranging the center: millimeter; h L Inner cylinder thickness, unit: millimeter; h w Is the outer cylinder thickness, unit: millimeter;
(2) according to the structural size of the current transformer, the lead capacitor C is arranged n Calculating to obtain a capacitance C without end screen segment m And end screen section capacitor C d Performing calculation with no end screen section capacitance C m The calculation can be performed using concentric cylindrical capacitors:
wherein epsilon is the complex dielectric constant of the oil-impregnated paper; epsilon 0 8.854 × 10 as the vacuum dielectric constant -12 Fa/m; r is a radical of hydrogen Λ For lead wire section department the lambda main screen equivalent radius, unit: millimeter; r is i For the lead wire department the ith end screen equivalent radius, unit: millimeter; l is (Λ) Is Λ anLength of the main screen without end screen, unit: millimeter;
capacitor C with end screen section d The calculation can be carried out according to the number of the end screens, and the expression is calculated by the main capacitor of the ith end screen section:
in the formula, epsilon is the complex dielectric constant of the oil-impregnated paper; epsilon 0 8.854 × 10 as the vacuum dielectric constant -12 Fa/m; l is a radical of an alcohol d Length of end screen, unit: millimeter; Δ L is the screen gradient difference at each end, unit: millimeter; delta d Insulation thickness between end screens, unit: millimeter;
therefore, the lead capacitor C of the current transformer with n end screens between the kth main screen and the k-1 main screen kn Can be expressed as:
in the formula, n is the number of end screens, unit: a plurality of;
(3) total capacitance C from the first I main screen to the Λ main screen in the inverted current transformer A Can represent the upper main insulation capacitance C T And lead wire capacitance C kn The parallel calculation of (a) is performed,
performing frequency Wen Pingyi reduction on the basic dielectric parameters of the oil-impregnated paper in different temperature regions as shown in the formula (7) to obtain a basic data main curve, and performing frequency-temperature reverse translation reduction in an actual test to obtain basic oil-impregnated paper dielectric response data at an actual test temperature as shown in the formula (8);
in the formula (f) T For the frequency required to translate to the T temperature, the unit: hertz; f. of 0 To test frequency, unit: hertz; t is the temperature of the desired translation, in units: kelvin; t is 0 To test temperature, unit: kelvin; Δ E (τ) is the relaxation activation energy of oil-impregnated paperboard in units: kilojoules per mole; k is Boltzmann constant, and has a size of 1.38 × 10 -23 Joule/kelvin.
In the first step, different testing temperatures are-40 ℃ to 40 ℃; the frequency domain dielectric response test frequency range 10 -3 Hz～10 3 Hz; the range of the water content of the oil-immersed paper is 0.5% -5%; the aging degree of the oil-impregnated paper, namely the polymerization degree range of the oil-impregnated paper is 300-1000.
In specific implementation, a schematic diagram of structural dimensions of an upper portion and a lead end in calculation of a total capacitance of an oil paper insulation in an inverted current transformer is shown in fig. 2, wherein a four-layer end screen is taken as an example in a lead end structure in fig. 2.
The method for obtaining the frequency domain dielectric response curve of the inverted current transformer comprises the following steps: in fig. 3, hi is a voltage electrode, lo is a measuring electrode, and Ground is a Ground electrode. And all secondary side wiring terminals 3 of the mutual inductor are in short circuit and are grounded, and meanwhile, the zero screen terminal 2 is disconnected from the ground. During testing, the voltage output Lo and the measuring end of the insulation diagnosis analyzer FDS are connected with the primary side bus terminal 1 of the transformer respectively, the current input Hi is connected with the secondary side zero screen terminal 2 of the transformer, and the specific wiring mode is shown in figure 3.
Placing a tested current transformer with 66kV voltage level in a high-low temperature test oven, simulating the actual environment temperature, and testing the frequency domain dielectric response curve of the current transformer at three typical temperatures of 40 ℃, 0 ℃ and-40 ℃ respectively, wherein the test frequency band is 10 -3 Hz～10 3 Hz, and the insulation state is quantitatively analyzed by the method according to the curve, and the loss factor test curves at three test temperatures are shown in figure 4. Such as the change rule of graph curveIt can be known that the low-frequency section test curve is gradually reduced along with the reduction of the test temperature, and the high-frequency section test curve is gradually increased, and the change rule of the low-frequency section test curve is consistent with the change of the single oil-impregnated paper dielectric loss factor curve.
Fitting calculation under different temperature regions is carried out on the test curve by adopting the method, the fitting calculation result is shown in figure 5, the content of water in the oil impregnated paper in the mutual inductor calculated under three temperatures is respectively 1.25%, 1.15% and 1.1%, the polymerization degree is respectively 685, 660 and 670, the absolute pair error of the calculation of the water content under different test temperatures is 0.15%, and the absolute error of the calculation of the polymerization degree is 25, so that the influence of the test temperature on the calculation result is eliminated, the engineering test requirement is met, and the effectiveness of the method is proved.
The method provides a direct measuring and calculating method for the insulation state evaluation of the inverted current transformer oil paper insulation system, and solves the problem that insulation aging or moisture state difference cannot be distinguished. The moisture content and the aging degree in the oil paper insulation of the inverted current transformer can be quantitatively evaluated in a high-temperature range and a low-temperature range by using a frequency domain dielectric response change rule and the like Guan Li and a technical means.
It is to be understood that the above-described embodiments are only some, and not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Claims (4)
1. An insulation wetting and aging evaluation method for an inverted current transformer is characterized by comprising the following steps of: comprises the following steps, which are sequentially carried out,
firstly, performing frequency domain dielectric response test on oil-impregnated paper with different water contents and different aging degrees through a frequency domain dielectric response test system at different test temperatures to obtain imaginary part and real part basic data of a complex dielectric constant;
step two, constructing a dielectric parameter representation method of the oil-impregnated paper-water composite dielectric system in temperature regions above zero DEG C and below zero DEG C respectively according to the dielectric response data of the oil-impregnated paper base with different water contents obtained by the test in the step one, and correcting the influence of the phase state change of water on the dielectric parameters;
step three, carrying out comparative analysis on the dielectric response data of the oil-impregnated paper base with different aging degrees obtained by the test in the step one, and establishing a dielectric parameter characteristic frequency band only influenced by the aging degree for distinguishing the influence of moisture and aging on the dielectric response data of the oil-impregnated paper base;
step four, calculating the total capacitance C from the I main screen to the Λ main screen in the inverted current transformer according to the voltage grade and size of the current transformer A ；
Step five, obtaining a frequency spectrum loss factor curve of the actually tested inverted current transformer at a certain testing temperature, and performing frequency Wen Fanxiang translation on the main dielectric parameter curve to obtain oil-impregnated paper basic dielectric data at the temperature, wherein the basic dielectric data is a complex dielectric constant;
step six, combining the dielectric parameter representation method of the oil-impregnated paper-water composite medium system constructed in the step two, and passing through the total capacitance C of the current transformer in the step four A Fitting calculation is carried out on the characteristic frequency band affected by the moisture in the actually measured loss factor curve, and the moisture content of the oil impregnated paper in the main insulation is obtained when the goodness of fit of the curve is less than or equal to 3%;
step seven, combining the aging basic data in the step three, and passing through the total capacitance C of the current transformer in the step four A And fitting and calculating the characteristic frequency band affected by aging in the actually measured loss factor curve by using the theoretical calculation expression, and obtaining the polymerization degree of the oil-impregnated paper in the main insulation when the goodness of fit of the curve is less than or equal to 3%.
2. The insulation damp and aging evaluation method for the inverted current transformer according to claim 1, wherein in the fourth step, the total capacitance C from the I main screen to the Λ main screen inside the inverted current transformer A Is obtained by the following steps of (a) preparing,
(1) calculating the inverted current transformer according to the voltage grade and size of the current transformerUpper main insulation capacitor C T Equivalent to an eccentric ring capacitor C P An outer cylinder capacitor C W And an inner cylinder capacitor C L The calculation expression of each capacitance is as follows:
R A(I-Λ) ＝(r x(Λ) +r x(I) ) 2 -d (I-Λ) 2 +R G R B(I-Λ) ＝(r x(Λ) +r x(I) ) 2 -d (I-Λ) 2 -R G
C T ＝C P +C W +C L (2)
wherein epsilon is the complex dielectric constant of the oil-impregnated paper; epsilon 0 8.854 × 10 as the vacuum dielectric constant -12 Fa/m; r is x(Λ) Radius of the Λ main screen equivalent circle, unit: millimeter; r is a radical of hydrogen x(Ι) The radius of the main screen is equal to the radius of the secondary winding I of the ring part, and the unit is as follows: millimeter; d (Λ-Ι) The unit is the eccentric distance between the lambda main screen and the I main screen: millimeter; r is x(Ι) The distance from the eccentric circle center of the I main screen to the center of the busbar is represented by the unit: millimeter; r x(Λ) For the eccentric centre of a circle of lambda main screen to the distance at female row center, the unit: millimeter; r w(Λ) For the distance, the unit of lambda main screen eccentric circle outside to female arranging the center: millimeter; h L Inner cylinder thickness, unit: millimeter; h w Is the outer cylinder thickness, unit: millimeter;
(2) lead capacitor C of current transformer according to structure size of current transformer n Calculating to obtain a capacitance C without end screen segment m And end screen section capacitor C d Performing calculation with no end screen section capacitance C m The calculation can be performed using concentric cylindrical capacitors:
wherein epsilon is the complex dielectric constant of the oil-impregnated paper; epsilon 0 8.854 × 10 as the vacuum dielectric constant -12 Fa/m; r is Λ For lead wire section department the lambda main screen equivalent radius, unit: millimeter; r is i For the lead wire department the ith end screen equivalent radius, unit: millimeter; l is (Λ) For Λ main screen no-end screen length, unit: millimeter;
capacitor C with end screen section d The calculation can be carried out according to the number of the end screens, and the expression is calculated by the main capacitor of the ith end screen section:
in the formula, epsilon is the complex dielectric constant of the oil-impregnated paper; epsilon 0 8.854 × 10 as the vacuum dielectric constant -12 Fa/m; l is d Length of end screen, unit: millimeter; Δ L is the screen step difference at each end, unit: millimeter; delta d Insulation thickness between end screens, unit: millimeter;
therefore, the lead capacitor C of the current transformer with n end screens between the kth main screen and the k-1 main screen kn Can be expressed as:
in the formula, n is the number of end screens, unit: a plurality of;
(3) total capacitance C from the first I main screen to the Λ main screen in the inverted current transformer A Can represent the upper main insulation capacitance C T And lead wire capacitance C kn The parallel calculation of (a) is performed,
3. the insulation wetting and aging evaluation method of the inverted current transformer according to claim 1, characterized in that the concrete method of the fifth step is that the oil-impregnated paper basic dielectric parameters are subjected to frequency Wen Pingyi reduction in different temperature regions, as formula (7), a basic data main curve is obtained, and the basic oil-impregnated paper dielectric response data at the actual test temperature can be obtained as formula (8) through frequency-temperature reverse translation reduction in the actual test;
in the formula, f T For the frequency required to translate to the T temperature, the unit: hertz; f. of 0 To test frequency, unit: hertz; t is the temperature of the desired translation, in units: kelvin; t is a unit of 0 To test temperature, unit: kelvin; Δ E (τ) is the relaxation activation energy of oil-impregnated paperboard, unit: kilojoules per mole; k is Boltzmann constant, and has a size of 1.38 × 10 -23 Joule/kelvin.
4. The insulation wetting and aging evaluation method for the inverted current transformer according to claim 1, wherein the different test temperatures in the first step are-40 ℃ to 40 ℃; the frequency domain dielectric response test frequency range 10 -3 Hz～10 3 Hz; the range of the water content of the oil-immersed paper is 0.5% -5%; the aging degree of the oil-impregnated paper, namely the polymerization degree range of the oil-impregnated paper is 300-1000.
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Citations (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2003121404A (en) * | 2001-10-18 | 2003-04-23 | Mitsubishi Electric Corp | Deterioration diagnostic method of solid insulating material |
| WO2008026997A1 (en) * | 2006-08-29 | 2008-03-06 | Abb Research Ltd. | A method and a device for determining the moisture content in a part of the insulation of a power transformer during drying thereof |
| JP2012132767A (en) * | 2010-12-21 | 2012-07-12 | Mitsubishi Electric Corp | Insulation characteristic evaluation method for coils |
| CN102818974A (en) * | 2012-07-13 | 2012-12-12 | 云南电力试验研究院（集团）有限公司电力研究院 | Method for evaluating aging degree of main insulation of transformer |
| SE1300282A1 (en) * | 2013-04-16 | 2014-10-17 | Megger Ltd | Method and apparatus for determining power system parameters |
| US20150028885A1 (en) * | 2013-07-23 | 2015-01-29 | Atomic Energy Council - Institute Of Nuclear Energy Research | Method for evaluation of cable aging degradation based on slice sampling |
| CN108680613A (en) * | 2018-04-23 | 2018-10-19 | 三峡大学 | A method of assessing moisture in insulating paper using complex dielectric permittivity initial slope |
| CN110009236A (en) * | 2019-04-10 | 2019-07-12 | 哈尔滨理工大学 | A kind of oil-immersed power transformer built-in electrical insulation degree of aging quantitative evaluating method |
| CN110850178A (en) * | 2019-10-23 | 2020-02-28 | 广西电网有限责任公司电力科学研究院 | Insulation sleeve on-line frequency domain dielectric spectrum detection method |
| CN111812467A (en) * | 2020-07-16 | 2020-10-23 | 重庆大学 | Method for evaluating aging state of oil-impregnated transformer oil paper insulation system |
| CN112782537A (en) * | 2020-12-23 | 2021-05-11 | 南方电网电力科技股份有限公司 | Transformer bushing damp state evaluation method based on high-voltage frequency domain dielectric spectrum |
| CN113588733A (en) * | 2021-07-09 | 2021-11-02 | 深圳供电局有限公司 | Method and equipment for evaluating moisture content of oiled paper insulation |
-
2022
- 2022-10-09 CN CN202211226625.0A patent/CN115421013A/en active Pending
Patent Citations (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2003121404A (en) * | 2001-10-18 | 2003-04-23 | Mitsubishi Electric Corp | Deterioration diagnostic method of solid insulating material |
| WO2008026997A1 (en) * | 2006-08-29 | 2008-03-06 | Abb Research Ltd. | A method and a device for determining the moisture content in a part of the insulation of a power transformer during drying thereof |
| JP2012132767A (en) * | 2010-12-21 | 2012-07-12 | Mitsubishi Electric Corp | Insulation characteristic evaluation method for coils |
| CN102818974A (en) * | 2012-07-13 | 2012-12-12 | 云南电力试验研究院（集团）有限公司电力研究院 | Method for evaluating aging degree of main insulation of transformer |
| SE1300282A1 (en) * | 2013-04-16 | 2014-10-17 | Megger Ltd | Method and apparatus for determining power system parameters |
| US20150028885A1 (en) * | 2013-07-23 | 2015-01-29 | Atomic Energy Council - Institute Of Nuclear Energy Research | Method for evaluation of cable aging degradation based on slice sampling |
| CN108680613A (en) * | 2018-04-23 | 2018-10-19 | 三峡大学 | A method of assessing moisture in insulating paper using complex dielectric permittivity initial slope |
| CN110009236A (en) * | 2019-04-10 | 2019-07-12 | 哈尔滨理工大学 | A kind of oil-immersed power transformer built-in electrical insulation degree of aging quantitative evaluating method |
| CN110850178A (en) * | 2019-10-23 | 2020-02-28 | 广西电网有限责任公司电力科学研究院 | Insulation sleeve on-line frequency domain dielectric spectrum detection method |
| CN111812467A (en) * | 2020-07-16 | 2020-10-23 | 重庆大学 | Method for evaluating aging state of oil-impregnated transformer oil paper insulation system |
| CN112782537A (en) * | 2020-12-23 | 2021-05-11 | 南方电网电力科技股份有限公司 | Transformer bushing damp state evaluation method based on high-voltage frequency domain dielectric spectrum |
| CN113588733A (en) * | 2021-07-09 | 2021-11-02 | 深圳供电局有限公司 | Method and equipment for evaluating moisture content of oiled paper insulation |
Non-Patent Citations (2)
| Title |
|---|
| 张明泽: "变压器油纸绝缘老化含水率频域法定量评估", 《高电压技术》 * |
| 邹阳: "油纸绝缘特性研究及微水含量评估", 《仪器仪表学报》 * |
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