CN105513729A - Method for optimizing structure of zinc oxide arrester - Google Patents

Abstract

The invention discloses a method for optimizing the structure of a zinc oxide arrester. The method is implemented according to the following steps of firstly, establishing a geometry simulation model inside the arrester; secondly, conducting electric field voltage distribution and simulation calculation; thirdly, calculating the voltage bearing rate Vi and the voltage non-uniform distribution coefficient K on each zinc oxide resistor disc; fourthly, conducting comparison and optimization on the voltage bearing rates, modifying the dielectric constant epsilon r'li, finishing the optimization process, and recoding the relative dielectric constant of each resistor disc at the moment; fifthly, transforming the capacitance values of the resistor discs according to the optimization result of the fourth step, and obtaining the distribution mode of the resistor discs in the arrester. The problems that when the arrester is optimized through a method for increasing the main capacitance of the resistor discs in the prior art, the production cost of the arrester is increased and the pressure equalizing effect is not remarkable enough are solved.

Description

A kind of method of zinc oxide arrester structure optimization

Technical field

The invention belongs to lightning arrester structure optimization technical field, be specifically related to a kind of method of zinc oxide arrester structure optimization.

Background technology

Metal oxide arrester (MOA) obtains a wide range of applications in electric power system with its abnormal good nonlinear characteristic.For gapless MOA, if do not take effectively all to press measure, the voltage that the continuous operating voltage that the existence be in operation due to stray capacitance makes the resistor disc near the lightning arrester unit of high-pressure side bear is born than the resistor disc away from low-pressure end is high.For ac high-voltage MOA, because parts number is many, structure height size large, thus make the problem of voltage's distribiuting quite serious.The uneven of voltage's distribiuting will cause the operation chargeability of local electrical resistance sheet to raise, and then causes the aging quickening of this part resistor disc and thermal runaway occurs.Therefore, must take reasonably all to press measure to improve its voltage's distribiuting, the operation chargeability of controlling resistance sheet.

The calculating and measuring carrying out MOA voltage's distribiuting is exactly extremely important in the manufacturing and designing of MOA.The degree of irregularity voltage skewness coefficient of the voltage's distribiuting of AC gapless MOA is stated, and usually can determine with computing method or measurement method.In the past domestic and international is that master determines voltage's distribiuting nonuniformity coefficient with electric Field Calculation.

All pressures measure of metal oxide arrester generally comprises: control structure and grading ring size, configure suitable parallel equalizing capacitor and change the modes such as resistor disc main capacitance size.General program first determines the size of lightning arrester structure and grading ring, satisfied voltage's distribiuting nonuniformity coefficient just can be obtained by optimizing Equalized voltage ring construction size for the lightning arrester of≤330kV system, but especially for 1000kV AC extra high voltage MOA, then except control structure and grading ring size, also must can obtain desirable voltage's distribiuting nonuniformity coefficient by the suitable parallel equalizing capacitor of configuration for the lightning arrester of >=500kV electric pressure.Have document under existing grading shield structure, change resistor disc main capacitance size optimize lightning arrester resistor disc Potential distribution further by increasing resistor disc diameter, lightning arrester resistor disc along axis voltage's distribiuting with resistor disc relative dielectric constant ε _rincrease and be tending towards even.Existing entirety increases the method for resistor disc main capacitance, and shortcoming is that lightning arrester cost is produced in increase, all pressure effect is remarkable not.

Summary of the invention

The object of this invention is to provide a kind of method of zinc oxide arrester structure optimization, solve in prior art by the method increasing resistor disc main capacitance carry out lightning arrester optimize time, increase and produce the significant not problem of lightning arrester cost, all pressure effect.

The technical solution adopted in the present invention is, a kind of method of zinc oxide arrester structure optimization, specifically implements according to following steps:

Step 1, according to the dimensional parameters of zinc oxide arrester, sets up the geometric simulation model of lightning arrester inside,

Step 2, carry out voltage of electric field distribution and carry out the Electric Field Distribution situation that simulation calculation obtains the lightning arrester model set up in step 1, namely finite element method is utilized to carry out simulation calculation to the voltage's distribiuting of zinc oxide resistance sheet (MOA) in the lightning arrester model set up in step one, by finally obtaining the voltage data u that each resistor disc is born after analyzing _i(i=1,2,3 ... n);

According to step 2, step 3, show that the voltage data that each resistor disc is born calculates, the voltage obtained on every sheet zinc oxide resistance sheet bears rate V _iwith voltage's distribiuting nonuniformity coefficient K, these two parameters are using the target parameter as optimization;

Step 4, voltage and the voltage of the n calculated from step 3 resistor disc are born in rate, choose wherein maximum voltage and bear rate V _maxrate V is born with minimum voltage _min, and by formula a%=V _max-1, b%=V _max-V _mincalculate relative dielectric constant growth rate lower limit a% and upper limit b%;

To calculate on the i-th sheet resistor sheet and bear voltage V _icontrast with 1, and revise relative dielectric constant according to the result of contrast, revised relative dielectric constant is denoted as ε _r' _1i

When revising, work as V _i< 1 or V _i=1, keep constant for the relative dielectric constant of the i-th sheet resistor sheet, that is, ε _r' _1i=ε _r1i;

Work as V _iduring > 1, the relative dielectric constant of this resistor disc is revised, by the DIELECTRIC CONSTANT ε of the i-th sheet resistor sheet _r1iimprove a%, revised dielectric constant is designated as ε _r' _1i=ε _r1i* (1+a%).Wherein, i=1,2 ..., n;

Be ε by dielectric constant on the zinc oxide resistance sheet of result of calculation correction according to the method described above _r' _1i, and keep other parameter constants of modeling needs in step 1, according to the method in step 2 ~ 3, again carry out modeling, calculating voltage skewness COEFFICIENT K to the zinc oxide arrester after change relative dielectric constant, each resistor disc voltage bears rate V ' _i, and up-to-date voltage's distribiuting nonuniformity coefficient K and voltage bear the coefficient of variation σ of rate;

If the voltage's distribiuting nonuniformity coefficient K<K after improving ₀, and voltage bears the coefficient of variation σ < σ of rate ₀, then optimizing process is terminated, the relative dielectric constant of record every sheet resistor sheet now;

If voltage's distribiuting nonuniformity coefficient and voltage are born, rate is still discontented is enough to requirement, then the method repeating step 3 carries out cycle calculations and Modifying model;

If voltage's distribiuting nonuniformity coefficient and voltage bear the requirement that rate meets design standard, then terminate optimizing process, the relative dielectric constant of record every sheet resistor sheet now;

Step 5, according to the optimum results of step 4, transformation resistor disc capacitance, obtains the internal resistance sheet arrangement mode of final lightning arrester.

Feature of the present invention is also,

When setting up lightning arrester inner geometry simulation model in step 1, the parameter related to comprises:

Zinc oxide resistance sheet number n, the external diameter Φ of zinc oxide resistance sheet ₁₁, zinc oxide resistance sheet internal diameter Φ ₁₂, zinc oxide resistance sheet height H ₁, zinc oxide resistance sheet relative dielectric constant ε _r1;

The external diameter Φ of pad ₂₁, pad internal diameter Φ ₂₂, pad height H ₂, the conductivity G of gasket material ₂;

The external diameter Φ of insulating cylinder ₃₁, insulating cylinder internal diameter Φ ₃₂, insulating cylinder height H ₃, insulating cylinder relative dielectric constant ε _r3;

The external diameter Φ of insulating bar ₄₁, insulating bar height H ₄, insulating bar relative dielectric constant ε _r4;

The external diameter Φ of porcelain overcoat ₅₁, porcelain overcoat internal diameter Φ ₅₂, porcelain overcoat height H ₅, porcelain overcoat relative dielectric constant ε _r5; Support height H ₆;

Wherein, the relative dielectric constant ε of zinc oxide resistance sheet _r1be variable parameter, all the other are constant parameter entirely.

Step 3 must specifically be calculated as: the voltage u that every sheet resistor sheet that the potential and electric field distributions data acquisition calculated by step 2 goes out is born _i, find resistor disc to bear the maximum u of voltage _max, the voltage calculating i-th resistor disc according to formula (1) bears rate V _i

$V_i=\frac{u_i}{U_0/n}---\left(1\right)$

Wherein, U ₀for the rated voltage that lightning arrester is born, n is total number of lightning arrester resistor disc, u _iand V _irepresent the actual voltage that bears of i-th resistor disc respectively and voltage bears rate.

Calculate, voltage's distribiuting nonuniformity coefficient K

$K=\frac{u_{max}-U_0/n}{U_0/n}---\left(2\right)$

Calculate, voltage bears the coefficient of variation σ of rate simultaneously

$\mathrm{\&sigma;}=\frac{{\mathrm{\&Sigma;}}_{i=1}^n|V_i-1|}{n}---\left(3\right)$

The initial value of the voltage's distribiuting nonuniformity coefficient K calculated first is designated as K ₀, the initial value that voltage bears the coefficient of variation σ of rate is designated as σ ₀.

The invention has the beneficial effects as follows, the present invention is directed to metal zinc oxide lightning arrester because of its diverse location resistor disc voltage bears the problem of the uneven easy generation thermal runaway of rate, calculate by bearing rate to the voltage of lightning arrester internal oxidition zinc resistor disc, according to result of calculation, the method adopting segmentation to transform resistor disc electric capacity can improve zinc oxide resistance sheet voltage's distribiuting and voltage bears rate (chargeability), diverse location is adopted to the zinc oxide resistance sheet of different relative dielectric constant, make the voltage of resistor disc bear rate more to rationalize, convenient and easy, and it is cost-saving.

Accompanying drawing explanation

Fig. 1 is the flow chart of the method for a kind of zinc oxide arrester structure optimization of the present invention;

Fig. 2-1 is the outward appearance three-dimensional model diagram of the 330kV column zinc oxide arrester in the embodiment of the method for a kind of zinc oxide arrester structure optimization of the present invention;

Fig. 2-2 is internal structure profiles of the 330kV column zinc oxide arrester in the embodiment of the method for a kind of zinc oxide arrester structure optimization of the present invention;

Fig. 3 is 330kV column zinc oxide arrester Holistic modeling figure in the embodiment of the method for a kind of zinc oxide arrester structure optimization of the present invention;

Fig. 4 is the potential image of embodiment in the embodiment of the method for a kind of zinc oxide arrester structure optimization of the present invention;

Fig. 5 is the distribution map of the electric field of embodiment in the embodiment of the method for a kind of zinc oxide arrester structure optimization of the present invention;

Fig. 6 is that each resistor disc voltage of 330kV zinc oxide arrester of embodiment in the embodiment of the method for a kind of zinc oxide arrester of the present invention structure optimization bears rate curve figure;

Fig. 7 be the high-pressure side resistor disc relative dielectric constant of embodiment in the embodiment of the method for a kind of zinc oxide arrester structure optimization of the present invention be respectively 1000,800,750 and the relative dielectric constant of low-pressure end resistor disc when being 650 the voltage of resistor disc bear rate correlation curve.

Embodiment

Below in conjunction with the drawings and specific embodiments, the present invention is described in detail.

A method for zinc oxide arrester structure optimization, as shown in Figure 1, specifically implement according to following steps:

Step 1, according to the dimensional parameters of zinc oxide arrester, sets up the geometric simulation model of lightning arrester inside,

When setting up lightning arrester inner geometry simulation model, the parameter related to comprises:

Zinc oxide resistance sheet number n, the external diameter Φ of zinc oxide resistance sheet ₁₁, zinc oxide resistance sheet internal diameter Φ ₁₂, zinc oxide resistance sheet height H ₁, zinc oxide resistance sheet relative dielectric constant ε _r1;

The external diameter Φ of pad ₂₁, pad internal diameter Φ ₂₂, pad height H ₂, the conductivity G of gasket material ₂;

The external diameter Φ of insulating cylinder ₃₁, insulating cylinder internal diameter Φ ₃₂, insulating cylinder height H ₃, insulating cylinder relative dielectric constant ε _r3;

The external diameter Φ of insulating bar ₄₁, insulating bar height H ₄, insulating bar relative dielectric constant ε _r4;

The external diameter Φ of porcelain overcoat ₅₁, porcelain overcoat internal diameter Φ ₅₂, porcelain overcoat height H ₅, porcelain overcoat relative dielectric constant ε _r5;

Support height H ₆;

Wherein, the relative dielectric constant ε of zinc oxide resistance sheet _r1be variable parameter, all the other are constant parameter entirely;

Step 2, carries out voltage of electric field distribution and carries out the Electric Field Distribution situation that simulation calculation obtains the lightning arrester model set up in step 1,

Namely finite element method is utilized to carry out simulation calculation to the voltage's distribiuting of zinc oxide resistance sheet (MOA) in the lightning arrester model set up in step one, by finally obtaining the voltage data u that each resistor disc is born after analyzing _i(i=1,2,3 ... n).

Specifically, because the capacity current being approximated to linear change in the continuous current of MOA accounts for larger component, and nonlinear current in resistance property only accounts for a very little part, under continuous operating voltage, the distribution of the inner each current potential of MOA distributes by electric capacity, therefore MOA voltage's distribiuting problem can be converted into the Solve problems of electrostatic field.The electric field of finite element analysis software to MOA is utilized to analyze, the computation model of electromagnet phenomenon in power frequency system can be set up with the Maxwell equation under quasistatic condition, calculating due to quasi-static electric field follows the on all four rule with electrostatic field, and the numerical computations of zinc oxide arrester Potential distribution can solve according to electrostatic field.The research of zinc oxide arrester Electric Field Distribution is the problem of a finite region, when studying it, not only will know the CHARGE DISTRIBUTION in this region, also must provide electrostatic field at borderline boundary condition.Boundary value condition mainly contains Di Likelai boundary condition, Neumann boundary conditions and combined boundary condition three class.The computation model can setting up three-dimensional lightning arrester when zinc oxide arrester Potential distribution under calculating running status is studied, and three-dimensional geometric shapes computational accuracy is also higher than two dimensional model, at this moment applying three-dimensional Finite Element Method can only calculate lightning arrester and obtain Potential distribution.After the electric field of MOA is comprehensively analyzed, the voltage born of its resistor disc also just can obtain.

According to step 2, step 3, show that the voltage data that each resistor disc is born calculates, the voltage obtained on every sheet zinc oxide resistance sheet bears rate V _iwith voltage's distribiuting nonuniformity coefficient K, these two parameters are using the target parameter as optimization.

In the research of zinc oxide arrester Potential distribution, usual employing voltage bears rate to weigh the high low degree that voltage born by each resistor disc of lightning arrester, it is the virtual voltage that bears of each resistor disc and the ratio of theoretical average voltage, is called that the voltage of every sheet MOA bears rate, uses V _irepresent, lightning arrester under continuous operating voltage, the maximum voltage that metal oxide varistors sheet bears deduct its on average bear voltage after with its ratio on average bearing voltage, be called voltage's distribiuting nonuniformity coefficient, represent with K.

Concrete is calculated as:

The voltage u that every sheet resistor sheet that the potential and electric field distributions data acquisition calculated by step 2 goes out is born _i, find resistor disc to bear the maximum u of voltage _max, the voltage calculating i-th resistor disc according to formula (1) bears rate V _i

$V_i=\frac{u_i}{U_0/n}---\left(1\right)$

Wherein, U ₀for the rated voltage that lightning arrester is born, n is total number of lightning arrester resistor disc, u _iand V _irepresent the actual voltage that bears of i-th resistor disc respectively and voltage bears rate.

Calculate, voltage's distribiuting nonuniformity coefficient K

$K=\frac{u_{max}-U_0/n}{U_0/n}---\left(2\right)$

Calculate, voltage bears the coefficient of variation σ of rate simultaneously

The initial value of the voltage's distribiuting nonuniformity coefficient K calculated first is designated as K ₀, the initial value that voltage bears the coefficient of variation σ of rate is designated as σ ₀

Step 4, voltage and the voltage of the n calculated from step 3 resistor disc are born in rate, choose wherein maximum voltage and bear rate V _maxrate V is born with minimum voltage _min, and by formula a%=V _max-1, b%=V _max-V _mincalculate relative dielectric constant growth rate lower limit a% and upper limit b%.

To calculate on the i-th sheet resistor sheet and bear voltage V _icontrast with 1, and revise relative dielectric constant according to the result of contrast, revised relative dielectric constant is denoted as ε _r' _1i

When revising, work as V _i< 1 or V _i=1, keep constant for the relative dielectric constant of the i-th sheet resistor sheet, that is, ε _r' _1i=ε _r1i;

Work as V _iduring > 1, the relative dielectric constant of this resistor disc is revised, by the DIELECTRIC CONSTANT ε of the i-th sheet resistor sheet _r1iimprove a%, revised dielectric constant is designated as ε _r' _1i=ε _r1i* (1+a%).Wherein, i=1,2 ..., n.

Be ε by dielectric constant on the zinc oxide resistance sheet of result of calculation correction according to the method described above _r' _1i, and keep other parameter constants of modeling needs in step 1.According to the method in step 2 ~ 3, again carry out modeling, calculating voltage skewness COEFFICIENT K to the zinc oxide arrester after change relative dielectric constant, each resistor disc voltage bears rate V ' _i, and up-to-date voltage's distribiuting nonuniformity coefficient K and voltage bear the coefficient of variation σ of rate.

If the voltage's distribiuting nonuniformity coefficient K<K after improving ₀, and voltage bears the coefficient of variation σ < σ of rate ₀, then optimizing process is terminated, the relative dielectric constant of record every sheet resistor sheet now.

If voltage's distribiuting nonuniformity coefficient and voltage are born, rate is still discontented is enough to requirement, then the method repeating step 3 carries out cycle calculations and Modifying model.

If voltage's distribiuting nonuniformity coefficient and voltage bear the requirement that rate meets design standard, then terminate optimizing process, the relative dielectric constant of record every sheet resistor sheet now.

If voltage's distribiuting nonuniformity coefficient and voltage are born rate and still do not met the demands, then the method repeating step 3 carries out cycle calculations and Modifying model, until target parameter reaches the scope of design specified in GB or rower.Optimisation criteria is: the requirement that first should reach each class standard; The second, make moderate progress than before transformation.

Step 5, according to the optimum results of step 4, transformation resistor disc capacitance, namely considers to apply the such mode of the resistor disc of different relative dielectric constant and structure on same lightning arrester and bears rate problem not uniformly to improve the comparatively large and voltage of voltage nonuniformity coefficient on lightning arrester resistor disc.The structural relation of the mode that Electric Field Distribution and resistor disc are arranged and lightning arrester itself is very large, but this patent mainly considers to apply the such mode of the resistor disc of different relative dielectric constant on same lightning arrester to improve voltage nonuniformity coefficient and voltage bears rate, therefore thinks that the structure of lightning arrester itself is constant when design.

Embodiment:

For 330kV lightning arrester, specifically invention is described in detail.

(1) modeling pattern: Figure 2 shows that 330kV column zinc oxide arrester, zinc oxide resistance sheet number n=96 sheet, is divided into 2 joints, encloses material and voltage to each parts, afterwards grid division apply Finite Element and carry out potential and electric field distributions calculating.

Wherein each part dimension is:

(a) zinc oxide resistance sheet: the external diameter Φ of zinc oxide resistance sheet ₁₁the external diameter Φ of=85mm, zinc oxide resistance sheet ₁₁the height H of=26mm, zinc oxide resistance sheet ₁the relative dielectric constant ε of=22.5mm, zinc oxide resistance sheet _r1=650

(b) aluminium backing: the external diameter Φ of pad ₂₁the internal diameter Φ of=83mm, pad ₂₂the height H of=26mm, pad ₂=10mm, the conductivity G of gasket material ₂=2.9 × 10-8S/m

(c) insulating cylinder: the external diameter Φ of insulating cylinder ₃₁the internal diameter Φ of=134mm, insulating cylinder ₃₂the height H of=130mm, insulating cylinder ₃the relative dielectric constant ε of=1643mm, insulating cylinder _r3=3.0

(d) insulating bar: the external diameter Φ of insulating bar ₄₁the height H of=24mm, insulating bar ₄the relative dielectric constant ε of=1598mm, insulating bar _r4=3.1

(e) porcelain overcoat: the external diameter Φ of porcelain overcoat ₅₁the internal diameter Φ of=205mm, porcelain overcoat ₅₂the height H of=145mm, porcelain overcoat ₅the relative dielectric constant ε of=1670mm, porcelain overcoat _r5=5.0

(f) support height H ₆=3000mm

Zinc oxide resistance sheet voltage bears the calculating of rate: according to the potential and electric field distributions figure (Fig. 4 and Fig. 5) of step 1, gather out the voltage that every sheet resistor sheet is born, the voltage calculating i-th resistor disc according to formula (1) bears rate V _i.Result of calculation is made curve as shown in Figure 6,

Known U ₀=330kV, n=96, the voltage calculating 96 sheet resistor sheets according to formula (1) bears rate V _i, as shown in Figure 5.As can be seen from Figure 5, on zinc oxide arrester, the voltage of joint place resistor disc is born rate to bear rate than lower joint place voltage high, and voltage's distribiuting nonuniformity coefficient K is 0.17.Maximum voltage is born rate value and is about 1.17, and this part resistor disc is in the state of aging quickening for a long time, easily thermal runaway occurs.

(2) resistor disc dielectric constant is changed

According to result of calculation, maximum voltage bears rate V _max=1.17 and minimum voltage bear rate V _min=0.82, determine relative dielectric constant growth rate lower limit a%=0.17 and upper limit b%=0.35, only for V _ithe lightning arrester resistor disc of >1 part, is increased to its relative dielectric constant and is about 750 ~ 880.Again carry out simulation calculation according to parameter to model, the voltage calculated respectively on every sheet zinc oxide resistance sheet bears rate, selects optimum voltage to bear rate distribution.

The 48 sheet resistor sheet voltages due to zinc oxide arrester high-pressure side (upper joint) are born rate and are greater than 1, its relative dielectric constant is become 750,800 and 1000 respectively from original 650, remaining unchanged of low-pressure end (lower joint) 48 sheet resistor sheets, applies same modeling pattern and calculates its voltage and bear rate.Draw out voltage on the resistor disc after change and bear rate and the comparison diagram before changing, as shown in Figure 7.

Fig. 7 and Fig. 6 contrast can be found out, increase the voltage saving resistor disc under the dielectric constant of zinc oxide resistance sheet can improve lightning arrester and bear rate, the voltage that reduction saves resistor disc bears rate, make their voltage bear rate score more close to 1, resistor disc can play its dielectric strength to a greater extent.As can be known from Fig. 7, the relative dielectric constant of 48 sheet resistor sheets of high-pressure side (upper joint) be 800 voltages being bear rate curve than 750 more smoothly, voltage's distribiuting nonuniformity coefficient is more reasonable; But the relative dielectric constant of high-pressure side resistor disc is not more high better, when relative dielectric constant increases to 1000, make the voltage of lower end resistor disc bear rate on the contrary and extremely increase.Therefore in actual applications, we by progressively increasing the relative dielectric constant of zinc oxide resistance sheet, can verify, making the voltage's distribiuting nonuniformity coefficient of resistor disc and voltage bear rate and more rationalize repeatedly.

(3) according to simulation result, namely the resistor disc of differing dielectric constant is adopted to transform lightning arrester ZnO resistors chip architecture, upper joint adopts the resistor disc of bulky capacitor (relative dielectric constant is 800), lower joint adopts the resistor disc of small capacitances (relative dielectric constant is 650), and such Optimizing Reconstruction is born rate curve to the voltage's distribiuting nonuniformity coefficient of lightning arrester internal oxidition zinc resistor disc and voltage and is significantly improved.

Claims (3)

1. a method for zinc oxide arrester structure optimization, is characterized in that, specifically implements according to following steps:

Step 1, according to the dimensional parameters of zinc oxide arrester, sets up the geometric simulation model of lightning arrester inside,

Step 2, carry out voltage of electric field distribution and carry out the Electric Field Distribution situation that simulation calculation obtains the lightning arrester model set up in step 1, namely finite element method is utilized to carry out simulation calculation to the voltage's distribiuting of zinc oxide resistance sheet (MOA) in the lightning arrester model set up in step one, by finally obtaining the voltage data u that each resistor disc is born after analyzing _i(i=1,2,3 ... n);

According to step 2, step 3, show that the voltage data that each resistor disc is born calculates, the voltage obtained on every sheet zinc oxide resistance sheet bears rate V _iwith voltage's distribiuting nonuniformity coefficient K, these two parameters are using the target parameter as optimization;

Step 4, voltage and the voltage of the n calculated from step 3 resistor disc are born in rate, choose wherein maximum voltage and bear rate V _maxrate V is born with minimum voltage _min, and by formula a%=V _max-1, b%=V _max-V _mincalculate relative dielectric constant growth rate lower limit a% and upper limit b%;

To calculate on the i-th sheet resistor sheet and bear voltage V _icontrast with 1, and revise relative dielectric constant according to the result of contrast, revised relative dielectric constant is denoted as ε _r' _1i

When revising, work as V _i< 1 or V _i=1, keep constant for the relative dielectric constant of the i-th sheet resistor sheet, that is, ε _r' _1i=ε _r1i;

Work as V _iduring > 1, the relative dielectric constant of this resistor disc is revised, by the DIELECTRIC CONSTANT ε of the i-th sheet resistor sheet _r1iimprove a%, revised dielectric constant is designated as ε _r' _1i=ε _r1i* (1+a%); Wherein, i=1,2 ..., n;

Be ε by dielectric constant on the zinc oxide resistance sheet of result of calculation correction according to the method described above _r' _1i, and keep other parameter constants of modeling needs in step 1, according to the method in step 2 ~ 3, again carry out modeling, calculating voltage skewness COEFFICIENT K to the zinc oxide arrester after change relative dielectric constant, each resistor disc voltage bears rate V ' _i, and up-to-date voltage's distribiuting nonuniformity coefficient K and voltage bear the coefficient of variation σ of rate;

If the voltage's distribiuting nonuniformity coefficient K<K after improving ₀, and voltage bears the coefficient of variation σ < σ of rate ₀, then optimizing process is terminated, the relative dielectric constant of record every sheet resistor sheet now;

If voltage's distribiuting nonuniformity coefficient and voltage are born, rate is still discontented is enough to requirement, then the method repeating step 3 carries out cycle calculations and Modifying model;

If voltage's distribiuting nonuniformity coefficient and voltage bear the requirement that rate meets design standard, then terminate optimizing process, the relative dielectric constant of record every sheet resistor sheet now;

Step 5, according to the optimum results of step 4, transformation resistor disc capacitance, obtains the internal resistance sheet arrangement mode of final lightning arrester.

2. the method for a kind of zinc oxide arrester structure optimization according to claim 1, is characterized in that, when setting up lightning arrester inner geometry simulation model in described step 1, the parameter related to comprises:

Zinc oxide resistance sheet number n, the external diameter Φ of zinc oxide resistance sheet ₁₁, zinc oxide resistance sheet internal diameter Φ ₁₂, zinc oxide resistance sheet height H ₁, zinc oxide resistance sheet relative dielectric constant ε _r1;

The external diameter Φ of pad ₂₁, pad internal diameter Φ ₂₂, pad height H ₂, the conductivity G of gasket material ₂;

The external diameter Φ of insulating cylinder ₃₁, insulating cylinder internal diameter Φ ₃₂, insulating cylinder height H ₃, insulating cylinder relative dielectric constant ε _r3;

The external diameter Φ of insulating bar ₄₁, insulating bar height H ₄, insulating bar relative dielectric constant ε _r4;

The external diameter Φ of porcelain overcoat ₅₁, porcelain overcoat internal diameter Φ ₅₂, porcelain overcoat height H ₅, porcelain overcoat relative dielectric constant ε _r5;

Support height H ₆;

Wherein, the relative dielectric constant ε of zinc oxide resistance sheet _r1be variable parameter, all the other are constant parameter entirely.

3. the method for a kind of zinc oxide arrester structure optimization according to claim 1, is characterized in that, described step 3 must specifically be calculated as: the voltage u that every sheet resistor sheet that the potential and electric field distributions data acquisition calculated by step 2 goes out is born _i, find resistor disc to bear the maximum u of voltage _max, the voltage calculating i-th resistor disc according to formula (1) bears rate V _i

$V_i=\frac{u_i}{U_0/n}---\left(1\right)$

Wherein, U ₀for the rated voltage that lightning arrester is born, n is total number of lightning arrester resistor disc, u _iand V _irepresent the actual voltage that bears of i-th resistor disc respectively and voltage bears rate,

Calculate, voltage's distribiuting nonuniformity coefficient K

$K=\frac{u_{max}-U_0/n}{U_0/n}---\left(2\right)$

Calculate, voltage bears the coefficient of variation σ of rate simultaneously

$\mathrm{\&sigma;}=\frac{{\mathrm{\&Sigma;}}_{i=1}^n|V_i-1|}{n}---\left(3\right)$

The initial value of the voltage's distribiuting nonuniformity coefficient K calculated first is designated as K ₀, the initial value that voltage bears the coefficient of variation σ of rate is designated as σ ₀.