A design method and system for three-step composite insulator

Abstract

The invention relates to a design method for a three-step composite insulator, comprising the following steps: inputting design data, including the size data of a first-order core rod, a second-order core rod and a third-order core rod and the maximum wind speed under the design height of several working conditions; for any working condition, using the input design data, calculating the wind receiving area of ​​the insulator body and the wind force received; calculating the equivalent resultant force applied by the jumper to the end of the insulator according to the wind force received by the insulator body and the jumper data of a jumper string of a tension tower; calculating the equivalent section inertia moment of the insulator according to the size data of the first-order core rod, the second-order core rod and the third-order core rod; calculating the deflection of the end of the insulator according to the equivalent resultant force applied by the jumper to the end of the insulator and the equivalent section inertia moment of the insulator; verifying whether the electrical requirements are met according to the deflection of the end of the insulator under each working condition, if the requirements are met, outputting the design data, if not, adjusting the design data and repeating the above steps.

Description

Technical Field

[0001] The invention relates to a design method and system for a three-step composite insulator, belonging to the technical field of electrical equipment design. Background Art

[0002] Affected by typhoons, coastal overhead lines and tension tower jumper strings have insufficient gravity damping due to objective conditions. Under the action of strong winds, power frequency flashover tripping accidents often occur, which affects the stability of power consumption of power grid users and even causes factories to produce defective products and hospitals to stop operating. For this reason, power operation units mostly hope to use vertical fixed wind-proof composite insulators as jumper strings to greatly reduce the probability of wind-proof tripping. For coastal lines of 220kV and below, there are currently finalized products, and this type of insulator is an integrated structure (the insulator core rod is an equal-diameter cylinder, and the formula for the moment of inertia of the section is I = πD 4 / 64). At present, 500kV hard-supported wind-proof composite insulators have also been used in a small number of applications. Due to the large wind load of 500kV jumper series, the vertical fixed wind-proof composite insulator core rods that have been in operation usually adopt the two-step type, and there is no conceptual product for the three-step type. Considering that the two-step type is not natural enough in actual engineering applications due to the large relative diameter ratio, the designer found inspiration from the traditional Chinese painting method of bamboo (short and thick at the root, gradually becoming longer and thinner upwards) and thought of using a multi-section (step) type. At the same time, in order to simplify the manufacturer's production process, it is more appropriate to choose the three-step type. However, the existing three-step composite insulators do not have a specific parameter calculation solution. In the design, it can only be simulated and designed through material finite element simulation software, and the design efficiency is low. Summary of the invention

[0003] In order to solve the problems existing in the above-mentioned prior art, the present invention proposes a design method and system for a three-step composite insulator, and proposes a method for calculating the moment of inertia of a three-order variable-diameter cylinder section that meets various extreme conditions. The method can be used for design optimization of three-step composite insulators and design and verification of engineering tower head dimensions, thereby reducing the design difficulty.

[0004] The technical solution of the present invention is as follows:

[0005] On the one hand, the present invention provides a design method of a three-step composite insulator, wherein the three-step composite insulator comprises a first-step core rod, a second-step core rod and a third-step core rod which are arranged continuously and have diameters from large to small, and the first-step core rod, the second-step core rod and the third-step core rod are made of the same material. The design method comprises the following steps:

[0006] Input design data, including the size data of the first-order core rod, the second-order core rod and the third-order core rod and the maximum wind speed at the design height of the jumper string of the tension tower under several operating conditions;

[0007] For any operating condition, the wind-exposed area of ​​the insulator body and the wind force received are calculated using the input design data;

[0008] According to the wind force on the insulator body and the jumper data of the jumper string of the tension tower, the equivalent resultant force exerted by the jumper on the end of the insulator is calculated;

[0009] According to the dimension data of the first-order core rod, the second-order core rod and the third-order core rod, the equivalent section inertia moment of the insulator is calculated;

[0010] Calculate the deflection of the insulator end based on the equivalent resultant force applied by the jumper to the insulator end and the equivalent section inertia moment of the insulator;

[0011] According to the deflection of the insulator end under each operating condition, query the electrical engineering requirements and determine whether they meet the electrical requirements. If they meet the requirements, output the size data of the current first-order core rod, second-order core rod and third-order core rod. If they do not meet the requirements, adjust the size data of the first-order core rod, second-order core rod and third-order core rod and repeat the above steps.

[0012] Preferably, the method for calculating the wind receiving area and wind force of the insulator body by using the input design data is specifically as follows:

[0013] The following formula is used to calculate the wind-receiving area and wind force of the insulator body:

[0014]

[0015] Where A is the wind-exposed area of ​​the insulator body, a, b, c are the lengths of the first-order core rod, the second-order core rod, and the third-order core rod, respectively; T, R, K are the diameters of the first-order core rod, the second-order core rod, and the third-order core rod, respectively; P is the wind force on the insulator body; and v is the maximum wind speed at the design height of the jumper string of the tension tower under the corresponding operating conditions.

[0016] Preferably, the method for calculating the equivalent resultant force exerted by the jumper on the end of the insulator according to the wind force on the insulator body and the jumper data of the jumper string of the tension tower is specifically:

[0017] The equivalent force exerted by the jumper on the end of the insulator is calculated using the following formula:

[0018]

[0019] Where n is the number of jumper splits, A cdr , L cdr , D cdrare the wind pressure area of ​​the jumper, the length of a single jumper and the outer diameter of the jumper, respectively; x is the equivalent centroid position corresponding to the wind load on the composite insulator itself; W is the soft jumper tension; W0 is the installation tension of a phase jumper; g1 and g6 are the unit deadweight load of the conductor and the comprehensive load at maximum wind speed, respectively; F is the equivalent resultant force exerted by the jumper on the end of the insulator; L=a+b+c; θ is the angle formed by the soft jumpers on both sides of the jumper string.

[0020] Preferably, the method for calculating the equivalent section moment of inertia of the insulator according to the size data of the first-order core rod, the second-order core rod and the third-order core rod is specifically:

[0021] The equivalent section moment of inertia of the insulator is calculated using the following formula:

[0022]

[0023] Wherein, u0, u1, u2, m1 and m2 are all proportional coefficients, s is the calculated value, ε is the preset constant, π is the circumference of a circle, and I is the equivalent section moment of inertia of the insulator.

[0024] Preferably, the method for calculating the deflection of the insulator end is specifically as follows:

[0025] The deflection of the insulator end is calculated using the following formula:

[0026]

[0027] Where B is the stiffness under equivalent load, E is the bending elastic coefficient of the composite insulator, and y is the deflection of the insulator end.

[0028] On the other hand, the present invention provides a design system for a three-step composite insulator, wherein the three-step composite insulator comprises a first-step core rod, a second-step core rod and a third-step core rod which are arranged continuously and have diameters from large to small, and the first-step core rod, the second-step core rod and the third-step core rod are made of the same material, and the design system comprises:

[0029] A data input module is used to input design data, including the size data of the first-order core rod, the second-order core rod and the third-order core rod and the maximum wind speed at the design height of the jumper string of the tension tower under several operating conditions;

[0030] A wind receiving area and wind force calculation module is used to calculate the wind receiving area and wind force of the insulator body for any working condition using the input design data;

[0031] The equivalent resultant force calculation module is used to calculate the equivalent resultant force exerted by the jumper on the end of the insulator according to the wind force on the insulator body and the jumper data of the jumper string of the tension tower;

[0032] A section inertia calculation module is used to calculate the equivalent section inertia of the insulator according to the size data of the first-order core rod, the second-order core rod and the third-order core rod;

[0033] The deflection calculation module calculates the deflection of the insulator end according to the equivalent resultant force applied by the jumper to the insulator end and the equivalent section inertia moment of the insulator;

[0034] The verification module is used to query the electrical engineering requirements and determine whether the electrical requirements are met according to the deflection of the insulator end under each operating condition. If the requirements are met, the size data of the current first-order core rod, second-order core rod and third-order core rod are output; if not, the size data of the first-order core rod, second-order core rod and third-order core rod are adjusted and returned to recalculate the deflection of the insulator end under each operating condition.

[0035] Preferably, the method for the wind receiving area and wind force calculation module to calculate the wind receiving area and wind force received by the insulator body is specifically:

[0036] The following formula is used to calculate the wind-receiving area and wind force of the insulator body:

[0037]

[0038] Where A is the wind-exposed area of ​​the insulator body, a, b, c are the lengths of the first-order core rod, the second-order core rod, and the third-order core rod, respectively; T, R, K are the diameters of the first-order core rod, the second-order core rod, and the third-order core rod, respectively; P is the wind force on the insulator body; and v is the maximum wind speed at the design height of the jumper string of the tension tower under the corresponding operating conditions.

[0039] Preferably, the method for calculating the equivalent force exerted by the jumper on the end of the insulator by the equivalent force calculation module is as follows:

[0040] The equivalent force exerted by the jumper on the end of the insulator is calculated using the following formula:

[0041]

[0042] Where n is the number of jumper splits, A cdr , L cdr , D cdr are the wind pressure area of ​​the jumper, the length of a single jumper and the outer diameter of the jumper, respectively; x is the equivalent centroid position corresponding to the wind load on the composite insulator itself; W is the soft jumper tension; W0 is the installation tension of a phase jumper; g1 and g6 are the unit deadweight load of the conductor and the comprehensive load at maximum wind speed, respectively; F is the equivalent resultant force exerted by the jumper on the end of the insulator; L=a+b+c; θ is the angle formed by the soft jumpers on both sides of the jumper string.

[0043] Preferably, the method for calculating the equivalent moment of inertia of an insulator by the moment of inertia calculation module of the section is specifically as follows:

[0044] The equivalent section moment of inertia of the insulator is calculated using the following formula:

[0045]

[0046] Wherein, u0, u1, u2, m1 and m2 are all proportional coefficients, s is the calculated value, ε is the preset constant, π is the circumference of a circle, and I is the equivalent section moment of inertia of the insulator.

[0047] Preferably, the method for calculating the deflection of the insulator end by the deflection calculation module is specifically as follows:

[0048] The deflection of the insulator end is calculated using the following formula:

[0049]

[0050] Where B is the stiffness under equivalent load, E is the bending elastic coefficient of the composite insulator, and y is the deflection of the insulator end.

[0051] The present invention has the following beneficial effects:

[0052] The invention discloses a design method system for a three-step composite insulator. According to the characteristics of the three-step windproof composite insulator, the relevant theories of material mechanics and the understanding of elastic potential energy provide a corresponding section moment of inertia formula to calculate the equivalent section moment of inertia of the three-step cylinder and the overall deflection of the composite insulator. At the same time, the equal-diameter second-order and third-order conditions are taken into account, so that unified calculations can be easily performed in a computer program without relying on the finite element method, so a large amount of modeling time is not required, which greatly simplifies the design process and improves the design efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 This is a flow chart of a method according to Embodiment 1 of the present invention;

[0054] Figure 2 It is a schematic structural diagram of a three-step composite insulator in an embodiment of the present invention;

[0055] Figure 3 This is an example diagram of drawing an insulator gap circle calibration diagram in an embodiment of the present invention. DETAILED DESCRIPTION

[0056] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0057] It should be understood that the step numbers used in this document are only for convenience of description and are not intended to limit the order in which the steps are executed.

[0058] It should be understood that the terms used in the present specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the present specification and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.

[0059] The terms “include” and “comprising” indicate the presence of described features, integers, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or combinations thereof.

[0060] The term "and / or" means and includes any and all possible combinations of one or more of the associated listed items.

[0061] Embodiment 1:

[0062] See also Figure 1 This embodiment provides a design method for a three-step composite insulator. Figure 2 The top of the three-step composite insulator is a flange plate for connecting to a pole tower, and the bottom of the flange plate is continuously provided with a first-step core rod, a second-step core rod and a third-step core rod with diameters from large to small from top to bottom, and the first-step core rod, the second-step core rod and the third-step core rod are made of the same material.

[0063] The design method comprises the following steps:

[0064] Step S100, input design data, including the length a and diameter T of the first-order core rod, the length b and diameter R of the second-order core rod, the length c and diameter K of the third-order core rod, and the maximum wind speed at the design height of the tension tower jumper string under several operating conditions. In this embodiment, the operating conditions include four common conditions: power frequency overvoltage, operating overvoltage, lightning overvoltage, and live working. The maximum wind speed at the design height of the tension tower jumper string corresponding to each operating condition is queried according to the engineering meteorological condition table.

[0065] Step S201, selecting an operating condition (e.g., power frequency overvoltage), and using the input size data of the first-order core rod, the second-order core rod, and the third-order core rod and the wind speed data corresponding to the operating condition to calculate the wind receiving area of ​​the insulator body and the wind force received;

[0066] Step S202, calculating the equivalent resultant force exerted by the jumper on the insulator end according to the wind force on the insulator body calculated corresponding to the current operating condition and the jumper data (known data) of the jumper string of the tension tower;

[0067] Step S203, calculating the equivalent section inertia moment of the insulator corresponding to the current size data according to the input size data of the first-order core rod, the second-order core rod and the third-order core rod;

[0068] Step S204, calculating the deflection of the insulator end under the current operating condition according to the equivalent resultant force applied by the jumper to the insulator end calculated corresponding to the current operating condition and the equivalent section inertia moment of the insulator under the current size data;

[0069] Step S205, select another operating condition, repeat the above steps S201 to S204, calculate the deflection of the insulator end under the corresponding operating condition, until the deflection of the insulator end under four operating conditions is calculated.

[0070] Step S300: According to the deflection of the insulator end under the four working conditions, the electrical safety distance corresponding to the four working conditions specified in the specification and the specific engineering clearance margin requirements (known conditions) are queried, and then the deflection of the insulator end under the four working conditions is respectively drawn as follows: Figure 3 In the insulator gap circle verification diagram shown, if the size data of the selected first-order core rod, second-order core rod and third-order core rod meet the electrical requirements, the size data of the current first-order core rod, second-order core rod and third-order core rod are output through verification. If not, the value of the diameter T of the first-order core rod is gradually increased in steps of 5 mm, and the above steps S100 to S205 are repeated until the gap circles drawn according to the deflections calculated according to the four working conditions meet the electrical requirements. Remember T at this time, and then fine-tune a, b, and c according to the principle of c≥b≥a. b, c proportional factors make the design parameters of the composite insulator more in line with the commonly used engineering data (for example, when the calculated a = 1.754m, a = 1.75m can be adjusted, and when the calculated diameter R = 6.48cm, R = 6.5cm). After adjustment, recalculate according to the adjusted dimensional data to verify that the gap circle drawn by the deflection calculated for the four operating conditions still meets the electrical requirements. Finally, the dimensional data of the current first-order core rod, second-order core rod and third-order core rod are output and submitted to the composite insulator manufacturer for processing.

[0071] As a preferred implementation of this embodiment, in step S201, the method of calculating the wind receiving area and wind force of the insulator body by using the input design data is specifically as follows:

[0072] The following formula is used to calculate the wind-receiving area and wind force of the insulator body:

[0073]

[0074] Where A is the wind-exposed area of ​​the insulator body, a, b, c are the lengths of the first-order core rod, the second-order core rod and the third-order core rod respectively, T, R, K are the diameters of the first-order core rod, the second-order core rod and the third-order core rod respectively, P is the wind force on the insulator body, in N, and v is the maximum wind speed at the design height of the jumper string of the tension tower under the corresponding operating conditions, in (m / s).

[0075] As a preferred implementation of this embodiment, in step S202, the method for calculating the equivalent resultant force exerted by the jumper on the end of the insulator according to the wind force on the insulator body and the jumper data of the jumper string of the tension tower is specifically as follows:

[0076] The equivalent force exerted by the jumper on the end of the insulator is calculated using the following formula:

[0077]

[0078] Where n is the number of jumper splits, A cdr , L cdr , D cdr are the wind pressure area of ​​the jumper, the length of a single jumper and the outer diameter of the jumper, respectively; x is the equivalent centroid position corresponding to the wind load on the composite insulator itself; W is the soft jumper tension; W0 is the installation tension of a phase jumper; g1 and g6 are the unit deadweight load of the conductor and the comprehensive load at maximum wind speed, respectively (which can be directly read from the stress characteristic table of the conductor (jumper) in the preliminary design stage of the line, which is equivalent to a known parameter, and the physical units of the two are the same); F is the equivalent resultant force exerted by the jumper on the end of the insulator; L=a+b+c; θ is the angle formed by the soft jumpers on both sides of the jumper string (this angle is determined by the planned rotation angle of the tension tower and is generally taken as equal to the planned rotation angle); in this formula, the units of length and area are all in the International System of Units, and the unit of force is N.

[0079] As a preferred implementation of this embodiment, in step S203, the method for calculating the equivalent section moment of inertia of the insulator according to the size data of the first-order core rod, the second-order core rod and the third-order core rod is specifically as follows:

[0080] The equivalent section moment of inertia of the insulator is calculated using the following formula:

[0081]

[0082] Where u0, u1, u2, m1 and m2 are all proportional coefficients, all dimensionless intermediate parameters; s is the calculated value, corresponding to the formula for the moment of inertia of a single-section cylindrical section (I = πD 4 / 64), the calculated value of the denominator 64 varies according to the ratio of the diameters and lengths of the three core rods; ε is a small value that does not affect the calculation result, and in this embodiment, it is taken as 0.000001; π is the circumference of a circle, which can be taken as 3.14; and I is the equivalent section moment of inertia of the insulator.

[0083] In (Equation 3), the length and diameter units are cm, so the calculated moment of inertia is more in line with engineering practices. The calculated value of s increases u i =1 (i=0,1,2), so (Formula 3) takes into account the calculation of the composite insulator in three modes: equal diameter, second order, and third order.

[0084] As a preferred implementation of this embodiment, in step S204, the method for calculating the deflection of the insulator end is specifically:

[0085] The deflection of the insulator end is calculated using the following formula:

[0086]

[0087] Where B is the stiffness under equivalent load, in N*cm 2 ; E is the bending elastic coefficient of the composite insulator, in N / cm 2 ; y is the deflection of the insulator end, in cm.

[0088] The method proposed in this embodiment is obtained based on the characteristics of the three-order wind-proof composite insulator and the basic properties of material mechanics. When the length ratio coefficient u of a certain order core rod is i In the extreme case of 1, the corresponding three types of equal-diameter composite insulator core rods have cross-sectional inertia moments that are numerically consistent with the calculation results of single-diameter core rods in material mechanics. It is worth noting that the materials of the three core rods must be the same in order to use this method for calculation.

[0089] Since the composite insulator corresponding to this embodiment is a vertical fixed composite insulator, its connection with the cross arm is "rigid connection" and it will not swing arbitrarily with the wind. Therefore, deflection displacement will occur under the action of bending moment. Therefore, when calculating the wind pressure of the jumper, it is not necessary to multiply it by the wind pressure unevenness coefficient.

[0090] The method proposed in this embodiment converts the uniform force of wind on the composite insulator into a concentrated load on the centroid of the composite insulator to simplify the calculation according to the characteristics of the line jumper string, and then the wind force on the insulator string itself, the wind force on the soft jumper, and the tension caused by the angle of the soft jumper are equivalent to the resultant force F applied to the end of the composite insulator;

[0091] According to the relevant theories of material mechanics and the understanding of elastic potential energy, the corresponding section inertia formula is given to calculate the equivalent section inertia moment of the three-step cylinder and the overall deflection of the composite insulator. The formula takes into account the second and third order of equal diameter, so it is very convenient to enter the formula in a computer program (such as a spreadsheet) for unified calculation.

[0092] To demonstrate the superiority of the method proposed in this embodiment, the specific application scenarios and application effects of this embodiment are provided below:

[0093] For a 500kV jumper, the jumper length is L cdr =28m, number of splits is 4, outer diameter of jumper is 26.82mm, maximum wind speed is 43.5m / s, ratio of jumper wind load to deadweight load is 2.237, jumper angle is 40°, installation tension is 200N per phase. The structural parameters of vertical fixed composite insulator are as follows: a=1.25m, b=1.50m, c=2.25m, L=5.0m, T=9cm, R=7cm, K=4.5cm, bending elastic coefficient E=4.5N / cm 2 , calculate the equivalent section moment of inertia I and the deflection y at the end of the insulator.

[0094] According to (Formula 1) and (Formula 2), the intermediate results are as follows:

[0095]

[0096]

[0097] According to the above calculation results, F is taken as 4000N during design.

[0098] According to (Equation 3), we can obtain s = 23.53 and the equivalent section inertia moment I = 259.3 cm 4 According to (Formula 4), the insulator end deflection y = 142.9 cm is obtained.

[0099] Assuming that the design F remains unchanged, when the lengths of a, b, and c change, a series of results are calculated as shown in the following table:

[0100] <![CDATA[u0]]> <![CDATA[u1]]> <![CDATA[u2]]> a(m) b(m) c(m) T(cm) <![CDATA[m1=R / T]]> <![CDATA[m2=K / R]]> S <![CDATA[I(cm 2 )]]> y(cm) Remark 1 0 0 5 0 0 9 0.78 0.643 64.00 322.1 115.0 Thick rods with equal diameter 0 1 0 0 5 0 9 0.78 0.643 64.00 117.9 314.2 Equal diameter rod 0 0 1 0 0 5 9 0.78 0.643 64.00 20.1 1840.0 Equal diameter thin rod 0.612 0.388 0 3.06 1.94 0 9 0.50 1.000 45.38 228.3 162.2 No medium diameter rod 0.33 0.33 0.33 1.67 1.67 1.67 9 0.78 0.643 30.45 258.8 143.1 Three equal parts 0.25 0.3 0.45 1.25 1.5 2.25 9 0.78 0.643 23.53 259.3 142.9 Calculation example 0.28 0.32 0.4 1.4 1.6 2 9 0.72 0.720 25.70 245.6 150.8 0.25 0.4 0.35 1.25 2 1.75 9 0.78 0.643 27.25 254.0 145.8 0.25 0.45 0.3 1.25 2.25 1.5 9 0.78 0.643 29.33 250.6 147.8 0.25 0.5 0.25 1.25 2.5 1.25 9 0.78 0.643 31.57 246.9 150.0 0.25 0.55 0.2 1.25 2.75 1 9 0.78 0.643 33.96 243.0 152.4 0.25 0.6 0.15 1.25 3 0.75 9 0.78 0.643 36.50 238.9 155.0

[0101] From the table above, we can see that the larger the ratio of thick rods, the smaller the deflection. When u0+u1=0, it is equivalent to a single thin rod. According to I=πd 4 / 64(3.14*4.5^4 / 64=20.1cm 4 ) is the same as the calculated value of I in the above table. When u0 = 1, it is equivalent to a single thick rod. According to I = πD 4 / 64 is also the same as the calculated value of I in the above table. The formula of y is the basic formula of material mechanics. The key lies in how to calculate the equivalent value of s.

[0102] In the theory of material mechanics, only the formula for the moment of inertia of a single cylindrical body with equal diameter is given: I = πD 4 / 64, and there is no ready-made formula for reference for the equivalent moment of inertia of the third-order variable diameter cylinder. Due to the nonlinear characteristics of material mechanics, there is no ability to derive a simple and perfect analytical calculation formula based on theory. This embodiment, based on relevant theories and combined with its own understanding of the elastic potential energy of material mechanics, has obtained a formula for the moment of inertia of the third-order variable diameter cylinder section that meets various limit conditions, which can be used for the design optimization of three-step ladder-shaped composite insulators and the design and verification of engineering tower head dimensions, reducing the design difficulty. In the past, the design of such problems could only be simulated and designed through material finite element simulation software. This embodiment can calculate the moment of inertia and deflection of the section of the third-order variable diameter cylindrical composite insulator core rod, and does not rely on the finite element method, so it does not need to spend a lot of modeling time, greatly simplifying the design process, thereby improving the design efficiency.

[0103] Embodiment 2:

[0104] This embodiment provides a design system for a three-step composite insulator, wherein the three-step composite insulator comprises a first-step core rod, a second-step core rod, and a third-step core rod which are arranged continuously and have diameters from large to small, and the first-step core rod, the second-step core rod, and the third-step core rod are made of the same material. The design system comprises:

[0105] A data input module is used to input design data, including the size data of the first-order core rod, the second-order core rod and the third-order core rod and the maximum wind speed at the design height of the jumper string of the tension tower under several operating conditions; this module is used to implement the solution of step S100 as described in the first embodiment, which will not be repeated here;

[0106] A wind receiving area and wind force calculation module is used to calculate the wind receiving area and wind force of the insulator body for any operating condition using the input design data; this module is used to implement the solution of step S201 as described in the first embodiment, which will not be described in detail here;

[0107] An equivalent resultant force calculation module is used to calculate the equivalent resultant force applied by the jumper to the end of the insulator according to the wind force on the insulator body and the jumper data of the jumper string of the tension tower; this module is used to implement the solution of step S202 as described in the first embodiment, and will not be repeated here;

[0108] A section inertia calculation module, used to calculate the equivalent section inertia of the insulator according to the size data of the first-order core rod, the second-order core rod and the third-order core rod; this module is used to implement the solution of step S203 as described in the first embodiment, which will not be described in detail here;

[0109] A deflection calculation module is used to calculate the deflection of the insulator end according to the equivalent resultant force applied by the jumper to the insulator end and the equivalent section inertia moment of the insulator. This module is used to implement the solution of step S204 as described in the first embodiment, and will not be described in detail here.

[0110] The verification module is used to query the electrical engineering requirements and determine whether the electrical requirements are met according to the deflection of the insulator end under each operating condition. If the requirements are met, the size data of the current first-order core rod, second-order core rod and third-order core rod are output; if not, the size data of the first-order core rod, second-order core rod and third-order core rod are adjusted and returned to recalculate the deflection of the insulator end under each operating condition. This module is used to implement the solution of step S300 as described in Example 1, which will not be repeated here.

[0111] As a preferred implementation of this embodiment, the method for the wind receiving area and wind force calculation module to calculate the wind receiving area and wind force received by the insulator body is specifically as follows:

[0112] The following formula is used to calculate the wind-receiving area and wind force of the insulator body:

[0113]

[0114] Where A is the wind-exposed area of ​​the insulator body, a, b, c are the lengths of the first-order core rod, the second-order core rod and the third-order core rod respectively, T, R, K are the diameters of the first-order core rod, the second-order core rod and the third-order core rod respectively, P is the wind force on the insulator body, in N, and v is the maximum wind speed at the design height of the jumper string of the tension tower under the corresponding operating conditions, in (m / s).

[0115] As a preferred implementation of this embodiment, the method for the equivalent force calculation module to calculate the equivalent force applied by the jumper to the end of the insulator is specifically:

[0116] The equivalent force exerted by the jumper on the end of the insulator is calculated using the following formula:

[0117]

[0118] Where n is the number of jumper splits, A cdr , L cdr , D cdr are the wind pressure area of ​​the jumper, the length of a single jumper and the outer diameter of the jumper, respectively; x is the equivalent centroid position corresponding to the wind load on the composite insulator itself; W is the soft jumper tension; W0 is the installation tension of a phase jumper; g1 and g6 are the unit deadweight load of the conductor and the comprehensive load at maximum wind speed, respectively (which can be directly read from the stress characteristic table of the conductor (jumper) in the preliminary design stage of the line, which is equivalent to a known parameter, and the physical units of the two are the same); F is the equivalent resultant force exerted by the jumper on the end of the insulator; L=a+b+c; θ is the angle formed by the soft jumpers on both sides of the jumper string (this angle is determined by the planned rotation angle of the tension tower and is generally taken as equal to the planned rotation angle); in this formula, the units of length and area are all in the International System of Units, and the unit of force is N.

[0119] As a preferred implementation of this embodiment, the method for the section inertia moment calculation module to calculate the equivalent section inertia moment of the insulator is specifically:

[0120] The equivalent section moment of inertia of the insulator is calculated using the following formula:

[0121]

[0122] Where u0, u1, u2, m1 and m2 are all proportional coefficients, all dimensionless intermediate parameters; s is the calculated value, corresponding to the formula for the moment of inertia of a single-section cylindrical section (I = πD 4 / 64), the calculated value of which varies according to the ratio of the diameters and lengths of the three core rods; ε is a small value that does not affect the calculation result, and is set to prevent the denominator from being 0 when the computer program is used for calculation. In this embodiment, 0.000001 is taken; π is the circumference of a circle, which can be 3.14; and I is the equivalent section moment of inertia of the insulator.

[0123] In (Equation 3), the length and diameter units are cm, so the calculated moment of inertia is more in line with engineering practices. The calculated value of s increases u i =1 (i=0,1,2), so (Formula 3) takes into account the calculation of the composite insulator in three modes: equal diameter, second order, and third order.

[0124] As a preferred implementation of this embodiment, the method for the deflection calculation module to calculate the deflection of the insulator end is specifically:

[0125] The deflection of the insulator end is calculated using the following formula:

[0126]

[0127] Where B is the stiffness under equivalent load, in N*cm 2 ; E is the bending elastic coefficient of the composite insulator, in N / cm 2 ; y is the deflection of the insulator end, in cm.

[0128] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A design method for a three-step composite insulator, wherein the three-step composite insulator comprises a first-step core rod, a second-step core rod and a third-step core rod which are arranged continuously and have diameters from large to small, and the first-step core rod, the second-step core rod and the third-step core rod are made of the same material, characterized in that: The design method comprises the following steps: Input design data, including the size data of the first-order core rod, the second-order core rod and the third-order core rod and the maximum wind speed at the design height of the jumper string of the tension tower under several operating conditions; For any operating condition, the wind-exposed area of ​​the insulator body and the wind force received are calculated using the input design data; According to the wind force on the insulator body and the jumper data of the jumper string of the tension tower, the equivalent resultant force exerted by the jumper on the end of the insulator is calculated; According to the dimension data of the first-order core rod, the second-order core rod and the third-order core rod, the equivalent section inertia moment of the insulator is calculated; Calculate the deflection of the insulator end based on the equivalent resultant force applied by the jumper to the insulator end and the equivalent section inertia moment of the insulator; According to the deflection of the insulator end under each operating condition, query the electrical engineering requirements and determine whether they meet the electrical requirements. If they meet the requirements, output the size data of the current first-order core rod, second-order core rod and third-order core rod. If they do not meet the requirements, adjust the size data of the first-order core rod, second-order core rod and third-order core rod and repeat the above steps. The method for calculating the equivalent resultant force exerted by the jumper on the end of the insulator according to the wind force on the insulator body and the jumper data of the jumper string of the tension tower is specifically as follows: The equivalent force exerted by the jumper on the end of the insulator is calculated using the following formula: Where n is the number of jumper splits, They are the wind pressure area of ​​the jumper, the length of a single jumper and the outer diameter of the jumper. To approximate the equivalent centroid position corresponding to the wind load on the composite insulator itself, is the pull force of the soft jumper, Install tension for one-phase jumper. , are the unit deadweight load of the conductor and the comprehensive load at maximum wind speed, respectively; F is the equivalent force exerted by the jumper on the end of the insulator. =a+b+c, is the angle formed by the soft jumpers on both sides of the jumper string; a, b, c are the lengths of the first-order core rod, the second-order core rod and the third-order core rod respectively; T, R, K are the diameters of the first-order core rod, the second-order core rod and the third-order core rod respectively; P is the wind force on the insulator body, The maximum wind speed at the design height of the jumper string of the tension tower under the corresponding operating conditions; The method for calculating the equivalent section inertia moment of the insulator according to the dimension data of the first-order core rod, the second-order core rod and the third-order core rod is specifically as follows: The equivalent section moment of inertia of the insulator is calculated using the following formula: In the formula, , , , and are proportional coefficients, is the calculated value, is a preset constant, π is the circumference of a circle, is the equivalent section moment of inertia of the insulator.

2. The design method of a three-step composite insulator according to claim 1, characterized in that: The method for calculating the wind receiving area and wind force of the insulator body by using the input design data is specifically as follows: The following formula is used to calculate the wind-receiving area and wind force of the insulator body: Where A is the wind-exposed area of ​​the insulator body, a, b, c are the lengths of the first-order core rod, the second-order core rod, and the third-order core rod, respectively; T, R, K are the diameters of the first-order core rod, the second-order core rod, and the third-order core rod, respectively; P is the wind force on the insulator body; It is the maximum wind speed at the design height of the tension tower jumper string under the corresponding operating conditions.

3. The design method of a three-step composite insulator according to claim 1, characterized in that: The method for calculating the deflection of the insulator end is specifically as follows: The deflection of the insulator end is calculated using the following formula: Where B is the stiffness under equivalent load, E is the bending elastic coefficient of the composite insulator, and y is the deflection of the insulator end.

4. A design system for a three-step composite insulator, wherein the three-step composite insulator comprises a first-step core rod, a second-step core rod and a third-step core rod which are arranged continuously and have diameters from large to small, and the first-step core rod, the second-step core rod and the third-step core rod are made of the same material, characterized in that: The design system includes: A data input module is used to input design data, including the size data of the first-order core rod, the second-order core rod and the third-order core rod and the maximum wind speed at the design height of the jumper string of the tension tower under several operating conditions; A wind receiving area and wind force calculation module is used to calculate the wind receiving area and wind force of the insulator body for any working condition using the input design data; The equivalent resultant force calculation module is used to calculate the equivalent resultant force exerted by the jumper on the end of the insulator according to the wind force on the insulator body and the jumper data of the jumper string of the tension tower; A section inertia calculation module is used to calculate the equivalent section inertia of the insulator according to the size data of the first-order core rod, the second-order core rod and the third-order core rod; The deflection calculation module calculates the deflection of the insulator end according to the equivalent resultant force applied by the jumper to the insulator end and the equivalent section inertia moment of the insulator; A verification module is used to query the electrical engineering requirements and determine whether the electrical requirements are met according to the deflection of the insulator end under each operating condition. If the requirements are met, the size data of the current first-order core rod, second-order core rod and third-order core rod are output; if not, the size data of the first-order core rod, second-order core rod and third-order core rod are adjusted and the deflection of the insulator end under each operating condition is returned to be recalculated; The method for calculating the equivalent force applied by the jumper to the end of the insulator by the equivalent force calculation module is as follows: The equivalent force exerted by the jumper on the end of the insulator is calculated using the following formula: Where n is the number of jumper splits, They are the wind pressure area of ​​the jumper, the length of a single jumper and the outer diameter of the jumper. To approximate the equivalent centroid position corresponding to the wind load on the composite insulator itself, is the pull force of the soft jumper, Install tension for one-phase jumper. , are the unit deadweight load of the conductor and the comprehensive load at maximum wind speed, respectively; F is the equivalent force exerted by the jumper on the end of the insulator. =a+b+c, is the angle formed by the soft jumpers on both sides of the jumper string; a, b, c are the lengths of the first-order core rod, the second-order core rod and the third-order core rod respectively; T, R, K are the diameters of the first-order core rod, the second-order core rod and the third-order core rod respectively; P is the wind force on the insulator body, The maximum wind speed at the design height of the jumper string of the tension tower under the corresponding operating conditions; The method for calculating the equivalent moment of inertia of an insulator by the moment of inertia calculation module of the section is specifically as follows: The equivalent section moment of inertia of the insulator is calculated using the following formula: In the formula, , , , and are proportional coefficients, is the calculated value, is a preset constant, π is the circumference of a circle, is the equivalent section moment of inertia of the insulator.

5. A design system for three-step composite insulators according to claim 4, characterized in that: The method for calculating the wind receiving area and wind force of the insulator body by the wind receiving area and wind force calculation module is specifically as follows: The following formula is used to calculate the wind-receiving area and wind force of the insulator body: Where A is the wind-exposed area of ​​the insulator body, a, b, c are the lengths of the first-order core rod, the second-order core rod, and the third-order core rod, respectively; T, R, K are the diameters of the first-order core rod, the second-order core rod, and the third-order core rod, respectively; P is the wind force on the insulator body; It is the maximum wind speed at the design height of the tension tower jumper string under the corresponding operating conditions.

6. A design system for three-step composite insulators according to claim 4, characterized in that: The method for calculating the deflection of the insulator end by the deflection calculation module is specifically as follows: The deflection of the insulator end is calculated using the following formula: Where B is the stiffness under equivalent load, E is the bending elastic coefficient of the composite insulator, and y is the deflection of the insulator end.

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