A method and system for matching the carrying capacity of a transmission line system

Abstract

A method and system for matching the bearing capacity of a transmission line system, comprising: determining the failure sequence of each component in the transmission line system and the safety factor of each component; calculating a matching adjustment coefficient for each component based on the failure sequence of the transmission line system components and the safety factor of each component; and calculating the bearing capacity of each component under different failure sequences based on the matching adjustment coefficient of each component. This method can guide the overall design of the line and improve the rationality and economy of the transmission line design.

Description

Technical Field

[0001] The present invention relates to the field of power transmission lines, and in particular to a method and system for matching the bearing capacity of a power transmission line system. Background Art

[0002] The development process of transmission line design methods can be roughly divided into three periods: in the first period, the transmission line design adopted the allowable stress design method (single safety factor method); thereafter, in the second period, the adjustment factor was considered for the line wind load; in the third period, the limit state design method based on probability theory and the design expression of partial factors were adopted.

[0003] Currently, line design tends to focus on individual component design, while overall reliability is often determined through empirical analysis. In some transmission line designs, towers and foundations are designed using the limit state method, while other components like ground wires and insulators are designed using the safety factor method, resulting in a theoretical mismatch. These differing design approaches lead to inconsistent reliability metrics for each system component: towers are used as a reliability indicator, while components like ground wires use a safety factor. Because the safety factor method fails to account for variations in product quality, components with the same safety factor may exhibit varying reliability.

[0004] Currently, there is little research on the reliability of transmission line systems. In the United States, a design method for overall line reliability has been introduced, which allows the selection of line reliability coefficients, but does not provide a matching relationship between the load-bearing capacity of each line component. Summary of the Invention

[0005] In order to solve the above-mentioned deficiencies in the prior art, the present invention provides a method and system for matching the bearing capacity of a transmission line system.

[0006] The technical solution provided by the present invention is:

[0007] A method for determining the carrying capacity of a transmission line system, the method comprising:

[0008] Determine the failure sequence of each component in the transmission line system and the safety factor of each component;

[0009] Calculating a matching adjustment factor for each component based on a failure sequence of the transmission line system components and a safety factor of each component;

[0010] The bearing capacity of each component under different failure sequences is calculated based on the matching adjustment coefficient of each component.

[0011] Preferably, the determination of the safety factor of each component includes:

[0012] Calculate the equivalent safety factor of each component under each working condition based on different working conditions;

[0013] Calculate the average value of the equivalent safety factor of each component based on the safety factor of each component under each working condition to obtain the safety factor of each component;

[0014] The components of the transmission line include: poles, hardware, ground wires, insulators and foundations.

[0015] Preferably, the failure sequence of the transmission line system components includes:

[0016] First failure order: tower is partially damaged, hardware fails, ground wire is broken, insulator is damaged, and foundation is intact;

[0017] Second failure sequence: the hardware is damaged, the ground wire falls off, and the tower, insulator and foundation are intact;

[0018] The third failure sequence: the ground wire is broken, but the tower, hardware, insulators and foundation are intact;

[0019] Fourth failure sequence: the hardware is damaged, the ground wire falls off, but the tower, insulator and foundation are intact;

[0020] The fifth failure sequence: the ground wire is broken, the insulator is damaged, and the hardware, pole tower and foundation are intact.

[0021] Preferably, the calculation of the matching adjustment coefficient based on the failure sequence of the transmission line system components and the safety factor of each component includes:

[0022] Acquiring strength data of each component, and obtaining a normal distribution of the strength probability of each component based on the strength data of each component;

[0023] Calculating the standard value and average value of each component based on the normal distribution of the strength probability of each component;

[0024] Based on the ratio of the standard value of each component to the average value, the coefficient of variation of each component is obtained;

[0025] The matching adjustment factor is calculated based on the coefficient of variation of each component, the failure sequence of the transmission line system components and the safety factor of each component.

[0026] Preferably, the calculation formula of the matching adjustment coefficient is as follows:

[0027] γ mn =K n / K n1

[0028] Where, γ mn is the matching adjustment coefficient of the nth component under different failure orders; K n is the matching safety factor of the nth component under different failure orders; K n1is the safety factor of the nth component; n is 1, 2, 3, 4, 5.

[0029] Preferably, the calculation formula for the component matching safety factor of each n-th component under the different failure orders is as follows:

[0030] K n =K n-1 ×γ mcn

[0031] Where K n-1 is the matching safety factor of the component preceding the nth component under different failure orders; γ mcn is the intensity matching coefficient of the nth component.

[0032] Preferably, the calculation formula of the strength matching coefficient of the nth component is as follows:

[0033]

[0034] Where α is the central safety factor of two adjacent components; δ R1 is the coefficient of variation of the first component of two adjacent components; δ R2 is the coefficient of variation of the second component among two adjacent components.

[0035] Preferably, the calculation formula for the nth component under different failure orders is as follows:

[0036] γ mn ×Load≤bearing capacity.

[0037] A load-carrying capacity matching system for a power transmission line system, the system comprising:

[0038] Determination module: used to determine the failure sequence of each component in the transmission line system and the safety factor of each component;

[0039] A first calculation module is configured to calculate a matching adjustment coefficient of each component based on the failure sequence of the transmission line system components and the safety factor of each component;

[0040] The second calculation module is used to calculate the bearing capacity of each component under different failure sequences based on the matching adjustment coefficient of each component.

[0041] Preferably, the determination module includes: a first calculation unit and a second calculation unit;

[0042] The first calculation unit is used to calculate the equivalent safety factor of each component under each working condition based on different working conditions;

[0043] The second calculation unit is used to calculate the average value of the equivalent safety factors of each component based on the safety factors of each component under each working condition to obtain the safety factor of each component;

[0044] The components of the transmission line include: poles, hardware, ground wires, insulators and foundations.

[0045] Compared with the prior art, the present invention has the following beneficial effects:

[0046] 1. The technical solution provided by the present invention determines the failure sequence and safety factor of each component in a transmission line system; calculates the matching adjustment coefficient of each component based on the failure sequence of the transmission line system components and the safety factor of each component; and calculates the bearing capacity of each component under different failure sequences based on the matching adjustment coefficient of each component. This can guide the overall design of the line and improve the rationality and economy of the transmission line design.

[0047] 2. The technical solution provided by the present invention can not only be used to calculate the strength matching coefficients of transmission line system components with different failure sequences and different confidence levels, but can also be used to calculate the strength matching coefficients of transmission line system components based on different component strength variation coefficient statistics and different safety factors under different working condition combinations. In this way, the transmission line system components can be made to carry out load-bearing work according to a predetermined failure sequence, thereby achieving the effects of minimizing disaster losses, minimizing repair costs, and achieving the fastest repair. The present invention can guide the overall design of the line and provide a reference for the differentiated design of transmission line system components. It has very important economic value and practical significance for the safe and economical operation of transmission lines. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 Schematic diagram of the flow of the method for matching the carrying capacity of a power transmission line system according to the present invention;

[0049] Figure 2 Schematic diagram of the structure of the power transmission line assembly of the present invention. DETAILED DESCRIPTION

[0050] In order to better understand the present invention, the present invention is further described below with reference to the accompanying drawings and examples.

[0051] The transmission line is a complex large-scale structural system, which includes five components: towers, ground wires, insulators, hardware, and foundations. In order to achieve the load-bearing work of the transmission line system components in a critical state according to the predetermined failure order, so as to achieve the purpose of minimizing disaster losses, minimizing repair costs, and achieving the fastest repair, the load-bearing capacity between the transmission line system components must be optimized and matched. Therefore, the present invention is proposed. The present invention can guide the overall design of the line and provide a reference for the differentiated design of the transmission line system components. It has very important economic value and practical significance for the safe and economical operation of the transmission line. Figure 1 The specific steps are as follows:

[0052] Step 1: Determine the failure sequence of each component in the transmission line system and the safety factor of each component;

[0053] Step 2: Calculating the matching adjustment coefficient of each component based on the failure sequence of the transmission line system components and the safety factor of each component;

[0054] Step 3: Calculate the bearing capacity of each component under different failure sequences based on the matching adjustment coefficient of each component.

[0055] This invention proposes five ideal failure sequences for transmission line system components, derives a formula for calculating the strength matching coefficient, and provides values ​​for the strength matching coefficient for transmission line system components with different failure sequences and confidence levels. The specific invention content is as follows.

[0056] Step 1: Determine the failure sequence of each component in the transmission line system and the safety factor of each component;

[0057] like Figure 2 As shown, taking into account the construction cost and repair difficulty, combined with engineering experience, the present invention proposes five ideal failure sequences for transmission line system components:

[0058] (1) Towers, hardware, ground wires, insulators, and foundations;

[0059] (2) Hardware, poles, ground wires, insulators, and foundations;

[0060] (3) Ground wire, pole tower, hardware, insulators, and foundation;

[0061] (4) Hardware, ground wires, poles, insulators, and foundations;

[0062] (5) Ground wire, insulator, hardware, pole tower and foundation.

[0063] The failure conditions of each component in the system are explained as follows:

[0064] For the first failure scenario, the pole tower is partially damaged, the hardware fails, the ground wire is broken, the insulator is damaged, and the foundation is intact; for the second scenario, the hardware is damaged, the ground wire falls off, and the pole tower, insulator, and foundation are intact; for the third scenario, the ground wire is broken, and the pole tower, hardware, insulator, and foundation are intact; for the fourth sequence, the hardware is damaged, the ground wire falls off, and the pole tower, insulator, and foundation are intact; for the fifth scenario, the ground wire is broken, the insulator is damaged, and the hardware, pole tower, and foundation are intact.

[0065] Step 2: Calculating the matching adjustment coefficient of each component based on the failure sequence of the transmission line system components and the safety factor of each component;

[0066] The calculation formula of intensity matching coefficient is derived using statistical methods.

[0067] Intensity matching coefficient γ mc It depends on the target probability of achieving the assumed failure sequence and the coefficient of variation of the two components. The present invention is based on the 90% confidence level that component R2 will not fail before component R1, i.e., 90% is taken as the confidence level of the target failure sequence. If the target probability of component R2's strength exceeding component R1's strength is set, then

[0068] P[(R2-R1)>0]=0.90=P (sof) (1)

[0069] Where R2 and R1 are the strengths of the two components respectively;

[0070] P (sof) is the probability of failure sequence, i.e. the probability of strength matching.

[0071] Intensity matching coefficient γ mc is the ratio of the strength exceeding limit of the two components. If the strength exceeding probability of the two components is e%, then

[0072]

[0073] The probability of achieving the strength matching target can be expressed by the reliability index β sof For intensity matching, this value is the confidence level P of achieving the intensity matching goal. φ .

[0074] P φ =F N (β sof ) (3)

[0075] Assuming that the component strength R2 and R1 are both normally distributed, the reliability index β sof It can be calculated by the following formula.

[0076]

[0077] Among them, σ R1 =δ R1 μ R1 , σ R2 =δ R2 μ R2 .

[0078] Where, σ R1 , σ R2 are the strength standard deviations of components R1 and R2 respectively; μ R1 、μ R2 is the average strength of components R1 and R2; δ R1 , δ R2is the strength variation coefficient of components R1 and R2.

[0079] Introducing the central safety factor α

[0080] α=μ R2 / μ R1 (5)

[0081] Then formula (4) can be transformed into:

[0082]

[0083] Solve the binomial equation from formula (7) to obtain the central safety factor α

[0084] α 2 [1-(β sof δ R2 ) 2 ]-2α+1-(β sof δ R1 ) 2 =0 (7)

[0085] If it is assumed that the component strengths R2 and R1 obey the log-normal distribution, R1 and R2 can be normalized equivalently, that is,

[0086]

[0087]

[0088] Substitute the normalized variable into the reliability index β sof The formula can be obtained:

[0089]

[0090] Solve the binomial equation from formula (11) and obtain the central safety factor α

[0091]

[0092] If the component strength exceeding limit e is taken as 10%, that is

[0093] (10%)R1=(1-1.28δ R1 )μ R1

[0094] (10%)R2=(1-1.28δ R2 )μ R2

[0095] Then from formula (2) we can get:

[0096]

[0097] Therefore, after calculating the central safety factor α by formula (7) or (11), the strength matching coefficient γ of two adjacent components can be determined by formula (12): mcn .

[0098] Based on the above calculation formula, the strength matching coefficients of transmission line system components at different failure sequences and different confidence levels can be calculated.

[0099] The strength data of five components of the existing transmission line system (towers, ground wires, insulators, hardware, and foundations) were collected, and the coefficient of variation and probability distribution type of the strength of each component were obtained through analysis, as shown in Table 1.

[0100] Table 1 Statistical characteristics of the strength of each component of the transmission line

[0101]

[0102] Table 2 summarizes the safety factors for the two most common operating conditions in current standards. The two load combinations are: Condition 1: maximum wind load, no ice load, and intact wires; Condition 2: maximum ice load, wind load at a corresponding wind speed, and intact wires. For simplicity, this paper only considers the equivalent safety factors for components with a voltage level of 500 kV (corresponding to a 50-year return period for ice and wind loads) and a structural safety level of II. Safety factors for other operating conditions and other design conditions can also be calculated using this method.

[0103] Table 2 Safety factors of various components of 500kV transmission lines (safety level II)

[0104]

[0105] In the present invention, the target confidence levels of the strength matching design are respectively taken as 90% and 80% for calculation.

[0106] The calculation results of the strength matching relationship of each component of the transmission line at the confidence level of 90% and 80% in the first failure sequence are shown in Table 3 and Table 4 respectively. Among them, which component is the main component and its matching coefficient γ mcn That is, it is taken as 1.00.

[0107] The selection of primary components is primarily determined by their cost. The first two failure order scenarios use the most expensive towers as the primary components. The last three failure order scenarios are specific to special lines, such as those with long spans, where conductors are the most important. Therefore, conductors are used as the primary components in the calculations.

[0108] Table 3 Strength matching relationship of each component of the line with tower as the main component in the first failure sequence (confidence level is 90%)

[0109]

[0110] Among them, the strength matching coefficient γ of adjacent components mc The matching safety factor K is obtained from the calculation formula of the present invention. n =K n-1 ×γ mcn , K n-1 is the matching safety factor of the component preceding the nth component under different failure orders; γ mcn is the strength matching coefficient of the nth component. For example: 2.038*1.412=2.877. Matching adjustment coefficient γ mn In order to facilitate the design of current specifications, the matching coefficient after adjusting the range based on the current specifications is considered, that is, γ mn =K2 / K1. For example: the matching adjustment coefficient of the ground wire γ mn =2.877 / 2.587=1.112.

[0111] Table 4 Strength matching relationship of each component of the line with tower as the main component in the first failure sequence (confidence level is 80%)

[0112]

[0113]

[0114] Based on Tables 3 and 4, the calculation results of the strength matching relationship of each component of the transmission line in the first failure sequence at the confidence levels of 90% and 80% are obtained, as shown in Table 5.

[0115] Table 5 Strength matching coefficient values ​​of each component in the first failure order

[0116]

[0117] Similarly, the calculation results of the strength matching relationship of each component of the transmission line at the confidence levels of 90% and 80% in the 2nd to 5th failure sequences are shown in Tables 6 to 9, respectively.

[0118] Table 6 Strength matching coefficient values ​​of each component in the second failure sequence

[0119]

[0120] Table 7 Strength matching coefficient values ​​of each component in the third failure sequence

[0121]

[0122] Table 8 Strength matching coefficient values ​​of each component in the fourth failure sequence

[0123]

[0124] Table 9 Strength matching coefficient values ​​of each component in the fifth failure sequence

[0125]

[0126] Step 3: Calculate the bearing capacity of each component under different failure sequences based on the matching adjustment coefficient of each component.

[0127] Determine the matching adjustment coefficient γ of each component m1 After that, the transmission line towers, foundations, ground wires, hardware and insulators can continue to be designed according to the current specifications, i.e. mn ×Load≤bearing capacity.

[0128] The present invention can not only be used to calculate the strength matching coefficient of transmission line system components with different failure sequences and different confidence levels, but also can be used to calculate the strength matching coefficient of transmission line system components based on different component strength variation coefficient statistical values ​​and different safety factors under different working condition combinations.

[0129] Based on the same concept invention, the present application also provides a load-bearing capacity matching system for a transmission line system, the system comprising:

[0130] Determination module: used to determine the failure sequence of each component in the transmission line system and the safety factor of each component;

[0131] A first calculation module is configured to calculate a matching adjustment coefficient of each component based on the failure sequence of the transmission line system components and the safety factor of each component;

[0132] The second calculation module is used to calculate the bearing capacity of each component under different failure sequences based on the matching adjustment coefficient of each component.

[0133] Preferably, the determination module includes: a first calculation unit and a second calculation unit;

[0134] The first calculation unit is used to calculate the equivalent safety factor of each component under each working condition based on different working conditions;

[0135] The second calculation unit is used to calculate the average value of the equivalent safety factors of each component based on the safety factors of each component under each working condition to obtain the safety factor of each component;

[0136] The components of the transmission line include: poles, hardware, ground wires, insulators and foundations.

[0137] Those skilled in the art will appreciate that the embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, the present application can adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application can adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code.

[0138] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the steps in the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0139] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0140] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0141] The above are merely embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention are included in the scope of the claims of the present invention to be approved.

Claims

1. A method for determining the carrying capacity of a transmission line system, characterized in that: The method comprises: Determine the failure sequence of each component in the transmission line system and the safety factor of each component; Calculating a matching adjustment factor for each component based on a failure sequence of the transmission line system components and a safety factor of each component; Calculating the bearing capacity of each component under different failure sequences based on the matching adjustment coefficient of each component; The calculation formula of the matching adjustment coefficient is as follows: c mn =K n / K n1 Where, γ mn K is the matching adjustment coefficient of the nth component under different failure orders; n is the matching safety factor of the nth component under different failure orders; K n1 is the safety factor of the nth component; n is 1, 2, 3, 4, 5; The calculation formula of the intensity matching coefficient of the nth component is as follows: Where α is the central safety factor of two adjacent components; δ R1 is the coefficient of variation of the first component of two adjacent components; δ R2 is the coefficient of variation of the second component among two adjacent components; The calculation formula for the nth component under different failure orders is as follows: γ mn ×Load≤bearing capacity.

2. The method according to claim 1, wherein The determination of the safety factor of each component includes: Calculate the equivalent safety factor of each component under each working condition based on different working conditions; Calculate the average value of the equivalent safety factor of each component based on the safety factor of each component under each working condition to obtain the safety factor of each component; The components of the transmission line include: poles, hardware, ground wires, insulators and foundations.

3. The method according to claim 2, wherein The failure sequence of the transmission line system components includes: First failure order: tower is partially damaged, hardware fails, ground wire is broken, insulator is damaged, and foundation is intact; Second failure sequence: the hardware is damaged, the ground wire falls off, and the tower, insulator and foundation are intact; The third failure sequence: the ground wire is broken, but the tower, hardware, insulators and foundation are intact; Fourth failure sequence: the hardware is damaged, the ground wire falls off, but the tower, insulator and foundation are intact; The fifth failure sequence: the ground wire is broken, the insulator is damaged, and the hardware, pole tower and foundation are intact.

4. The method according to claim 3, wherein The calculating of the matching adjustment coefficient based on the failure sequence of the transmission line system components and the safety factor of each component includes: Acquiring strength data of each component, and obtaining a normal distribution of the strength probability of each component based on the strength data of each component; Calculating the standard value and average value of each component based on the normal distribution of the strength probability of each component; Based on the ratio of the standard value of each component to the average value, the coefficient of variation of each component is obtained; The matching adjustment factor is calculated based on the coefficient of variation of each component, the failure sequence of the transmission line system components and the safety factor of each component.

5. The method according to claim 1, wherein The calculation formula for the component matching safety factor of the nth component under the different failure orders is as follows: K n =K n-1 ×γ mcn Where K n-1 is the matching safety factor of the component preceding the nth component under different failure orders; γ mcn is the intensity matching coefficient of the nth component.

6. A load-carrying capacity matching system for a power transmission line system, characterized in that: The system comprises: Determination module: used to determine the failure sequence of each component in the transmission line system and the safety factor of each component; A first calculation module is configured to calculate a matching adjustment coefficient of each component based on the failure sequence of the transmission line system components and the safety factor of each component; A second calculation module is used to calculate the bearing capacity of each component under different failure orders based on the matching adjustment coefficient of each component; The calculation formula of the matching adjustment coefficient is as follows: c mn =K n / K n1 Where, γ mn K is the matching adjustment coefficient of the nth component under different failure orders; n is the matching safety factor of the nth component under different failure orders; K n1 is the safety factor of the nth component; n is 1, 2, 3, 4, 5; The calculation formula of the intensity matching coefficient of the nth component is as follows: Where α is the central safety factor of two adjacent components; δ R1 is the coefficient of variation of the first component of two adjacent components; δ R2 is the coefficient of variation of the second component among two adjacent components; The calculation formula for the nth component under different failure orders is as follows: γ mn ×Load≤bearing capacity.

7. The system according to claim 6, wherein: The determination module includes: a first calculation unit and a second calculation unit; The first calculation unit is used to calculate the equivalent safety factor of each component under each working condition based on different working conditions; The second calculation unit is used to calculate the average value of the equivalent safety factors of each component based on the safety factors of each component under each working condition to obtain the safety factor of each component; The components of the transmission line include: poles, hardware, ground wires, insulators and foundations.

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