CN105956269A - Method for acquiring relationship between transformer winding state and inter-pancake capacitance parameter - Google Patents

Abstract

The invention discloses a method for acquiring the relationship between a transformer winding state and an inter-pancake capacitance parameter. The method comprises the following steps: establishing a 1/2 three-dimensional model of each of a transformer winding and an iron core according to an actual transformer size; setting a relative dielectric constant of transformer oil; setting the surface of a winding of loading voltage as a terminal boundary condition; setting the iron core and the transformer oil tank as a grounding boundary condition; respectively computing the ground capacitance of the winding of each loading voltage; and finally solving the capacitance between two adjacent windings by using the solved power energy.

Description

A kind of obtain the method for capacitance parameter relation between transformer winding state and cake

Technical field

The invention belongs to the technical field of transformator software emulation, obtain Transformer Winding particularly to one The method of capacitance parameter relation between state and cake.

Background technology

Since entering 21 century, China has stepped into the track of fast development, each along with industry and economic dispatch Developing rapidly of field, every profession and trade increases rapidly for the demand of electric energy, important as social development Ensure, after the construction that experienced by supertension and two electric pressures of extra-high voltage, before China's electrical network is in Not some scales.Data show, 2010 is annual, and China's gross generation is 42065.4 hundred million kilowatt hours, Relatively last year increases by 13.2%, and the proportion accounting for world's generated energy is 19.7%, follows the U.S. closely and is positioned at second place of the world； To the end of the year 2010, whole nation generating equipment capacity is 9.66 hundred million kilowatts, and relatively last year increases by 10.56%, China Electrical network scale now ranks first in the world.Social production and people's lives improve constantly for electricity consumption requirement will The safe operation of power system and reliable power supply carry to very important status.As improve electric pressure, The capital equipment of extension transmission distance, power transformer is in leading position in power system.Therefore, All stable operation to transformator that needs of the economy of operation of power networks and society is had higher requirement.

According to incompletely statistics, 1995 to 2005 Nian Jian China 110kV and above transformator have an accident altogether 443 (wherein after 2003, data are the statistical data of national grid): all because of winding event in accident The accident hindered and cause has 315, and the 71.1% of the total number of units of the accident that accounts for, wherein, owing to winding resistance to shorting is strong The Accident of Transformer that degree causes not has 178, and the 40.2% of the total number of units of the accident that accounts for accounts for the total accident of winding 56.5%.From statistical data, the Accident of Transformer caused because of winding deformation is at power system transformer Accident is occupied the biggest proportion.Therefore, the detection of further investigation deformation of transformer winding and diagnostic method, To improving transformer production level, it is ensured that electric power netting safe running has positive meaning.

But the inside of high-power transformer employs substantial amounts of copper cash, its cost is the most sufficiently expensive, therefore makes Studying different method of testing with large-scale entity transformator is unpractical to the Detection results of winding deformation.For Solving this problem, winding deformation is examined by vast researcher Selection utilization equivalent circuit of transformer Survey method is studied and is analyzed.Wherein, the inductance in winding equivalent model and resistance parameter utilize test Instrument is easy to obtain concrete numerical value, but between cake, electric capacity cannot lead to due to the electrical connection between winding Cross test to obtain.Therefore, electric capacity between Transformer Winding cake is asked for by the commonly used analytic method of people. But this method is only applicable to the metallic object of symmetrical structure, for the winding then poor effect deformed, and There is no meter and the edge effect impact on capacitance.Therefore find electricity between a kind of accurately acquisition Transformer Winding cake The method holding parameter, so research winding deform after between cake the situation of change of electric capacity be that pole is necessary.

Summary of the invention

Present invention is primarily targeted at: for the problems referred to above, propose one and can preferably calculate difference Capacitance between the winding cake under transformer state, greatly simplifies the acquisition Transformer Winding shape of workload The method of capacitance parameter relation between state and cake.

In order to realize above-mentioned technical purpose, the step of this method is:

A kind of obtain the method for capacitance parameter relation between transformer winding state and cake, comprise the following steps:

Step 1: according to real transformer size, set up 1/2 mould of the winding of transformator, iron core and fuel tank Type, the relative dielectric constant of definition transformer oil, fuel tank and iron core are set to earth potential；

Step 2: this model is carried out finite element fission, is respectively provided with axially adjacent two in a winding Individual line cake is terminal on-load voltage, then arranges that to be not loaded with the winding of current excitation be floating potential, then Carry out calculating and respectively obtaining the direct-to-ground capacitance of two adjacent lines cakes；

Step 3: two adjacent lines cakes are set simultaneously and are terminal and load different voltage, calculate the most whole casing Interior electric energy, and it is calculated the electric capacity between two adjacent lines cakes；

Step 4: select two other axially adjacent line cake in a winding, repeats step 2-3, calculates Go out the electric capacity between all axially adjacent line cake in a winding.

Described a kind of obtain the method for capacitance parameter relation between transformer winding state and cake, described step In rapid 1,1/2 model of the winding of transformator, iron core and fuel tank includes high-pressure side winding, low-pressure side winding, Iron core, oil tank of transformer and transformer oil.

Described a kind of obtain the method for capacitance parameter relation between transformer winding state and cake, described mould In type:

The line cake number of described high voltage side of transformer winding or low-pressure side winding and real transformer high-pressure side around The line cake number of group or low pressure winding is identical, and each line cake is all a columned metallic object；

Described iron core is divided into the lamination of different-thickness according to the structure of real transformer；

Described oil tank of transformer size is identical with real transformer fuel tank；

Described transformer oil is filled in around transformer high-voltage winding, low pressure winding and iron core；

High and low pressure winding is centered around on iron core respectively, and two windings overlap with the central shaft of iron core.

Described a kind of obtain the method for capacitance parameter relation between transformer winding state and cake, described step In rapid 1, fuel tank and iron core are set to earthy step is:

First select the whole outer surface of iron core, be set to ground connection boundary condition, then select oil tank of transformer Outer surface, be set to ground connection boundary condition.

Described a kind of obtain the method for capacitance parameter relation between transformer winding state and cake, described step The step of rapid 2 is:

Whole transformer model carries out finite element fission, and then arrange in a winding is axially adjacent First line cake is end boundary condition, and loads V₁Voltage, setting is not loaded with the winding surface of voltage and is Floating potential, is calculated the direct-to-ground capacitance C of first line cake₁₁；

Whole transformer model carries out finite element fission, and then arrange in same winding is axially adjacent Second line cake be end boundary condition, and load V₂Voltage, arranges the winding surface being not loaded with voltage For floating potential, it is calculated the direct-to-ground capacitance C of second line cake₂₂。

Described a kind of obtaining the method for capacitance parameter relation between transformer winding state and cake, its feature exists In, the step of described step 3 is:

Axially adjacent two line cake in setting steps 2 is end boundary condition simultaneously, and loads respectively V₁And V₂Voltage, is calculated the electric energy W of whole transformator_e12, then it is calculated two axially adjacent Capacitance C between two line cakes₁₂:

$C_{12}=\frac{2}{V_1{V}_2}\underset{\mathrm{\Ω}}{\∫}{W}_{e12}d\mathrm{\Ω}-\frac{1}{2}(\frac{V_1}{V_2}{C}_{11}+\frac{V_2}{V_1}{C}_{22})$

Wherein Ω is the volume of whole transformator.

The method have technical effect that, by capacitance calculation method, energy between the Transformer Winding cake of offer Electric capacity between enough cakes arranged easily under various different winding displacement fault, and the different winding state of extraction The most quick.

The invention will be further described below in conjunction with the accompanying drawings.

Accompanying drawing explanation

The transformator phantom sectional view that Fig. 1 provides for the present invention；

Capacitance variations situation between Transformer Winding cake during the axial displacement fault that Fig. 2 provides for the present invention；

Wherein, 1 is transformer high-voltage winding, and 2 is transformer low voltage winding, and 3 is transformer core, 4 For oil tank of transformer, 5 is transformer oil, and 6 is the winding surface being not loaded with voltage, and 7 is the axle in winding To first adjacent line cake, 8 is axially adjacent second the line cake in winding.

Detailed description of the invention

In order to make technical problem solved by the invention, technical scheme and beneficial effect clearer, Below in conjunction with drawings and Examples, the present invention is further elaborated.Should be appreciated that this place The specific embodiment described, only in order to explain the present invention, is not intended to limit the present invention.

With reference to Fig. 1 and Fig. 2, the present invention provides a kind of and obtains capacitance parameter pass between transformer winding state and cake The method of system, comprises the following steps:

In Comsol finite element software, modeling selects 3-dimensional model, physical field to be set to electrostatic field, meter Calculation module is stable state；

Set up normal 1/2 transformator phantom according to real transformer size, this model be along three-phase around The central point of group, is 1/2 volume by transformator vertical profile, includes high-pressure side winding 1, low-pressure side winding 2, Iron core 3, oil tank of transformer 4 and transformer oil 5；

Described high voltage side of transformer winding 1, has the cake number meeting real transformer high pressure winding, each line cake For all columned metallic object；

Described step down side winding 2, has the cake number meeting real transformer high pressure winding, each line cake For all columned metallic object；

Described iron core 3, is classified as the lamination of different-thickness according to the structure of real transformer；

The size that size is real transformer fuel tank of described oil tank of transformer 4；

Described transformer oil 5 is filled in around transformer high-voltage winding 1, low pressure winding 2 and iron core 3；

High-low pressure winding is centered around on iron core 3 respectively, and winding 1,2 overlaps with the central shaft of iron core 3；

According to the relative dielectric constant of the real transformer oil that test obtains, the transformer oil in model is set 5；

Arranging iron core 3 and oil tank of transformer 5 is earth potential, described concretely comprises the following steps: first select iron core 3 Whole outer surface, be set to ground connection boundary condition, then select the outer surface of oil tank of transformer 5, if It is set to ground connection boundary condition；

Comsol is utilized to carry the whole transformer model of function subdivision.Arrange in a winding is axially adjacent First line cake 7 be end boundary condition, numbered 1, and load V₁Voltage.Setting is not loaded with electricity The winding surface 6 of pressure is floating potential, and is set as the form of floating potential group.Calculate this transformator Model, can obtain the direct-to-ground capacitance C of line cake 7₁₁；

Comsol is utilized to carry the whole transformer model of function subdivision.Axial phase in same winding is set Adjacent second line cake 8 is end boundary condition, numbered 2, and load V₂Voltage.Setting is not loaded with The winding surface 6 of voltage is floating potential, and is set as the form of floating potential group.Calculate this transformation Device model, can obtain the direct-to-ground capacitance C of line cake 8₂₂；

Axially adjacent first and second the line cake simultaneously arranged in winding is end boundary condition, and loads V₁And V₂(V₁≠V₂) voltage.By being calculated the electric energy W of whole transformator_e12。

At this point it is possible to the capacitance C obtained between two windings 7 and 8₁₂:

$C_{12}=\frac{2}{V_i{V}_j}\underset{\mathrm{\Ω}}{\∫}{W}_{e12}d\mathrm{\Ω}-\frac{1}{2}(\frac{V_1}{V_2}{C}_{11}+\frac{V_2}{V_1}{C}_{22})---\left(1\right)$

Obtain electric capacity C between cake₁₂Also need to verify its correctness, and deeply grind based on this finite element method Capacitance variations situation between cake when studying carefully winding displacement, introduces change during winding axial displacement of generation in detail below Between depressor cake, electric capacity changes situation, and between cake during research other displacements of generation, capacitance variations can the rest may be inferred.

One, verification of correctness

Owing to entity Transformer Winding 1 and 2 is cake formula structure, therefore may utilize parallel plate capacitor and calculate public affairs Formula verifies that Comsol emulates the correctness of the capacitance tried to achieve, and the electric capacity C of plane-parallel capacitor calculates public affairs Formula is as follows:

$C=\frac{\mathrm{\ϵ}S}{4\mathrm{\π}kd}---\left(2\right)$

Wherein, ε is the relative dielectric constant of dielectric；π is 3.14；K is dielectric constant, and its value is 9 × 10^9, unit is N × m^2/C^2；D is two-plate spacing, and unit is m；S be two-plate just To area, unit is m^2.Emulate between the cake tried to achieve according to plane-parallel capacitor computing formula and Comsol Electric capacity, as shown in table 1.

Between the cake that the different calculation of table 1 is tried to achieve, capacity ratio is relatively

Two-plate spacing/mm	Analytic equation formula/pF	Comsol emulation/pF
			4.3	245.48	232.55

As shown in Table 1, it is of substantially equal that two kinds of calculations try to achieve capacitance, thus may certify that utilization Between Comsol calculating transformer cake, capacitance is feasible.

Two, axial displacement

According to this transformer model, when can try to achieve the high pressure winding 1 axial displacement of three positions of upper, middle and lower Capacitance variations situation between cake, as shown in Figure 2.

Electric capacity base between the cake from accompanying drawing 2 it can be seen that when upper, middle and lower high pressure winding 1 occurs axial displacement This is identical, it can thus be appreciated that during axial displacement, between the cake of Transformer Winding diverse location, electric capacity changes the most identical.

Claims (6)

1. one kind obtains the method for capacitance parameter relation between transformer winding state and cake, it is characterised in that Comprise the following steps:

Step 1: according to real transformer size, set up 1/2 mould of the winding of transformator, iron core and fuel tank Type, the relative dielectric constant of definition transformer oil, fuel tank and iron core are set to earth potential；

Step 2: this model is carried out finite element fission, is respectively provided with axially adjacent two in a winding Individual line cake is terminal on-load voltage, then arranges that to be not loaded with the winding of current excitation be floating potential, then Carry out calculating and respectively obtaining the direct-to-ground capacitance of two adjacent lines cakes；

Step 3: two adjacent lines cakes are set simultaneously and are terminal and load different voltage, calculate the most whole casing Interior electric energy, and it is calculated the electric capacity between two adjacent lines cakes；

Step 4: select two other axially adjacent line cake in a winding, repeats step 2-3, calculates Go out the electric capacity between all axially adjacent line cake in a winding.

Capacitance parameter relation between a kind of acquisition transformer winding state the most according to claim 1 and cake Method, it is characterised in that in described step 1,1/2 mould of the winding of transformator, iron core and fuel tank Type includes high-pressure side winding, low-pressure side winding, iron core, oil tank of transformer and transformer oil.

Capacitance parameter relation between a kind of acquisition transformer winding state the most according to claim 2 and cake Method, it is characterised in that in described model:

The line cake number of described high voltage side of transformer winding or low-pressure side winding and real transformer high-pressure side around The line cake number of group or low pressure winding is identical, and each line cake is all a columned metallic object；

Described iron core is divided into the lamination of different-thickness according to the structure of real transformer；

Described oil tank of transformer size is identical with real transformer fuel tank；

Described transformer oil is filled in around transformer high-voltage winding, low pressure winding and iron core；

High and low pressure winding is centered around on iron core respectively, and two windings overlap with the central shaft of iron core.

Capacitance parameter relation between a kind of acquisition transformer winding state the most according to claim 1 and cake Method, it is characterised in that in described step 1, fuel tank and iron core are set to earthy step For:

First select the whole outer surface of iron core, be set to ground connection boundary condition, then select oil tank of transformer Outer surface, be set to ground connection boundary condition.

Capacitance parameter relation between a kind of acquisition transformer winding state the most according to claim 1 and cake Method, it is characterised in that the step of described step 2 is:

Whole transformer model carries out finite element fission, and then arrange in a winding is axially adjacent First line cake is end boundary condition, and loads V₁Voltage, setting is not loaded with the winding surface of voltage and is Floating potential, is calculated the direct-to-ground capacitance C of first line cake₁₁；

Whole transformer model carries out finite element fission, and then arrange in same winding is axially adjacent Second line cake be end boundary condition, and load V₂Voltage, arranges the winding surface being not loaded with voltage For floating potential, it is calculated the direct-to-ground capacitance C of second line cake₂₂。

Capacitance parameter relation between a kind of acquisition transformer winding state the most according to claim 5 and cake Method, it is characterised in that the step of described step 3 is:

Axially adjacent two line cake in setting steps 2 is end boundary condition simultaneously, and loads respectively V₁And V₂Voltage, is calculated the electric energy W of whole transformator_e12, then it is calculated two axially adjacent Capacitance C between two line cakes₁₂:

$C_{12}=\frac{2}{V_1{V}_2}\underset{\mathrm{\Ω}}{\∫}{W}_{e12}d\mathrm{\Ω}-\frac{1}{2}(\frac{V_1}{V_2}{C}_{11}+\frac{V_2}{V_1}{C}_{22})$

Wherein Ω is the volume of whole transformator.