CN112069665B - Residual life and safety assessment method for transmission tower - Google Patents
Residual life and safety assessment method for transmission tower Download PDFInfo
- Publication number
- CN112069665B CN112069665B CN202010848757.1A CN202010848757A CN112069665B CN 112069665 B CN112069665 B CN 112069665B CN 202010848757 A CN202010848757 A CN 202010848757A CN 112069665 B CN112069665 B CN 112069665B
- Authority
- CN
- China
- Prior art keywords
- layer
- grade
- tower
- rod
- safety
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 238000000034 method Methods 0.000 title claims abstract description 30
- 230000005540 biological transmission Effects 0.000 title claims abstract description 28
- 230000007797 corrosion Effects 0.000 claims abstract description 101
- 238000005260 corrosion Methods 0.000 claims abstract description 101
- 238000012423 maintenance Methods 0.000 claims abstract description 41
- 238000011156 evaluation Methods 0.000 claims abstract description 26
- 238000013461 design Methods 0.000 claims abstract description 8
- 239000010410 layer Substances 0.000 claims description 185
- 239000000463 material Substances 0.000 claims description 34
- 238000005530 etching Methods 0.000 claims description 13
- 230000009467 reduction Effects 0.000 claims description 7
- 238000011161 development Methods 0.000 claims description 4
- 239000011247 coating layer Substances 0.000 claims description 2
- 230000008569 process Effects 0.000 abstract description 2
- 230000009466 transformation Effects 0.000 abstract description 2
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 4
- 229910000831 Steel Inorganic materials 0.000 description 4
- 239000010959 steel Substances 0.000 description 4
- 239000011248 coating agent Substances 0.000 description 2
- 238000000576 coating method Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 229910052742 iron Inorganic materials 0.000 description 2
- 230000002159 abnormal effect Effects 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 238000006731 degradation reaction Methods 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
Images
Classifications
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F30/00—Computer-aided design [CAD]
- G06F30/20—Design optimisation, verification or simulation
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06Q—INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR ADMINISTRATIVE, COMMERCIAL, FINANCIAL, MANAGERIAL OR SUPERVISORY PURPOSES; SYSTEMS OR METHODS SPECIALLY ADAPTED FOR ADMINISTRATIVE, COMMERCIAL, FINANCIAL, MANAGERIAL OR SUPERVISORY PURPOSES, NOT OTHERWISE PROVIDED FOR
- G06Q10/00—Administration; Management
- G06Q10/06—Resources, workflows, human or project management; Enterprise or organisation planning; Enterprise or organisation modelling
- G06Q10/063—Operations research, analysis or management
- G06Q10/0639—Performance analysis of employees; Performance analysis of enterprise or organisation operations
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06Q—INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR ADMINISTRATIVE, COMMERCIAL, FINANCIAL, MANAGERIAL OR SUPERVISORY PURPOSES; SYSTEMS OR METHODS SPECIALLY ADAPTED FOR ADMINISTRATIVE, COMMERCIAL, FINANCIAL, MANAGERIAL OR SUPERVISORY PURPOSES, NOT OTHERWISE PROVIDED FOR
- G06Q10/00—Administration; Management
- G06Q10/20—Administration of product repair or maintenance
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06Q—INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR ADMINISTRATIVE, COMMERCIAL, FINANCIAL, MANAGERIAL OR SUPERVISORY PURPOSES; SYSTEMS OR METHODS SPECIALLY ADAPTED FOR ADMINISTRATIVE, COMMERCIAL, FINANCIAL, MANAGERIAL OR SUPERVISORY PURPOSES, NOT OTHERWISE PROVIDED FOR
- G06Q50/00—Information and communication technology [ICT] specially adapted for implementation of business processes of specific business sectors, e.g. utilities or tourism
- G06Q50/06—Energy or water supply
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F2119/00—Details relating to the type or aim of the analysis or the optimisation
- G06F2119/04—Ageing analysis or optimisation against ageing
Landscapes
- Business, Economics & Management (AREA)
- Engineering & Computer Science (AREA)
- Human Resources & Organizations (AREA)
- Theoretical Computer Science (AREA)
- Economics (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Strategic Management (AREA)
- Marketing (AREA)
- Tourism & Hospitality (AREA)
- General Business, Economics & Management (AREA)
- Entrepreneurship & Innovation (AREA)
- Operations Research (AREA)
- Educational Administration (AREA)
- Development Economics (AREA)
- Quality & Reliability (AREA)
- Health & Medical Sciences (AREA)
- Water Supply & Treatment (AREA)
- Public Health (AREA)
- General Health & Medical Sciences (AREA)
- Primary Health Care (AREA)
- Game Theory and Decision Science (AREA)
- Computer Hardware Design (AREA)
- Evolutionary Computation (AREA)
- Geometry (AREA)
- General Engineering & Computer Science (AREA)
- Testing Of Devices, Machine Parts, Or Other Structures Thereof (AREA)
- Testing Resistance To Weather, Investigating Materials By Mechanical Methods (AREA)
Abstract
A method for evaluating the residual life and safety of a transmission tower comprises the steps of firstly calculating the residual life of each rod piece based on a specific corrosion model according to the critical corrosion thickness and the current corrosion thickness of each main rod piece and each diagonal rod piece in the tower, then carrying out layered evaluation on the tower according to an analytic hierarchy process to obtain the overall residual life and safety of the tower, and then providing a maintenance strategy of the tower according to the overall residual life and safety of the tower and the overall durability grade of the tower. The design not only realizes effective evaluation of the residual life of the tower, but also provides decision basis for transformation or removal of old lines of the power transmission project.
Description
Technical Field
The invention belongs to the technical field of transmission tower assessment, and particularly relates to a method for assessing residual life and safety of a transmission tower.
Background
Along with the approach of the design service life and the change of the operation environment, the phenomena that the transmission tower is aged or the use conditions are not in accordance with the original design requirements occur, the operation reliability level is reduced in different degrees, and the use safety of the transmission line is seriously influenced. The power transmission network undertakes the tasks of national power transmission, the importance of the power transmission network is self-evident, and as the most important power engineering facility of a power transmission line, the structure of a power transmission tower is the basic guarantee of normal operation of the line, so that the design of a method for evaluating the residual life and the safety of the power transmission tower is particularly important. At present, the evaluation on the service life of the tower is mainly carried out around the service life of tower body components and the service life of a foundation, and the accurate evaluation on the residual service life of the transmission tower cannot be realized.
Disclosure of Invention
The invention aims to provide a transmission tower residual life and safety assessment method which can reasonably and effectively assess the residual life of a tower and can provide a corresponding maintenance strategy according to the safety of the tower, aiming at the problems in the prior art.
In order to achieve the above purpose, the technical scheme of the invention is as follows:
a method for evaluating the residual life and the safety of a transmission tower comprises the evaluation of the residual life of the tower, and the evaluation of the residual life of the tower sequentially comprises the following steps:
a1, calculating the critical corrosion thickness delta of each main material rod piece and each diagonal material rod piece in the tower lim ；
A2, based on power function corrosion model, dividing the critical corrosion thickness delta lim Substituting the obtained data into the model to calculate the exposure time t of each rod piece to reach the critical corrosion thickness max And the current etching thickness delta 0 Substituting the obtained result into the model to calculate the exposure time t corresponding to the current corrosion thickness of each rod piece 0 Wherein the power function corrosion model is:
δ＝At n
in the formula, delta is the corrosion thickness, t is the exposure time, A is an initial corrosion rate constant, and n is a development trend constant of the corrosion rate along with the time;
a3, calculating the residual service life t of each rod piece according to the following formula:
t＝t max -t 0 ；
a4, calculating the residual life of the main rod pieces and the diagonal rod pieces of the body layer and the leg connecting layer of the tower by the following formula:
t 1 ＝min(t 1i )i＝1,2,…,n 1
in the above formula, t 1 The remaining life of the main member of the layer, t 1i The remaining life of the ith main bar member of the layer, n 1 Is the total number of main rods in the layer, t 2 The remaining life of the diagonal member of the layer, t 2i For the residual life of the ith diagonal member bar in the layer, n 2 The total number of the diagonal member bars in the layer;
a5, determining the residual life of the body layer and the leg connecting layer according to the contribution proportion of various rod pieces in the layer structure, and then determining the overall residual life T of the pole tower:
T＝min(T i )i＝1,2
in the above formula, T i For the remaining lifetime of the i-th layer structure,
the number of the jth type rod pieces in the ith layer is the proportion of the total number of the two type rod pieces in the ith layer,
the residual life of the ith layer and the jth rod piece is shown.
In step A1, the critical etching thickness delta lim Thickness delta from the current etching 0 Calculated by the following formula:
δ lim ＝δ s η lim
f yr ＝1-0.9852η
A r ＝0.5η 2 -1.5η+1
m＝r/(f yr A r )
δ 0 ＝δ s -(δ j -δ t )
in the above formula, δ s For the design thickness of the rod, η lim Maximum allowable corrosion rate of the rod, f yr Is the ratio of the yield strength of the rod after corrosion to the yield strength of the rod before corrosion, eta is the corrosion rate of the rod, A r Is the ratio of the cross-sectional area of the rod after corrosion to the cross-sectional area of the rod before corrosion, m is the strength reduction coefficient of the rod, r is the stress ratio of the rod, delta j Is the current detected thickness of the rod, delta t The coating thickness of the rods.
The evaluation method further comprises tower safety evaluation, and the tower safety evaluation sequentially comprises the following steps:
b1, calculating the safety of the main material rod piece and the diagonal material rod piece in the body layer and the leg connecting layer of the tower according to the following formula:
e＝1-δ 0 /δ lim
e 1 ＝min(e 1i )i＝1,2,…,n 1
in the above formula, e is the safety of the rod member, e 1 Safety of the main bar of the layer, e 1i The safety of the ith main bar member of the layer, n 1 Is the total number of main rods in the layer, e 2 Safety of diagonal member for the layer e 2i The safety of the ith diagonal member bar of the layer, n 2 The total number of the diagonal member bars in the layer;
b2, determining the safety degree of the body layer and the leg connecting layer according to the contribution proportion of various rod pieces in the layer structure, and then determining the overall safety degree E of the tower:
E＝min(E i )i＝1,2
in the above formula, E i As a security measure for the i-th layer structure,
the number of the jth type rod pieces in the ith layer is the proportion of the total number of the two type rod pieces in the ith layer,
the safety degree of the ith layer of the jth rod piece is obtained;
b3, determining a corresponding maintenance strategy according to the integral durability grade, the integral residual life and the integral safety degree of the tower, specifically:
if the tower meets any condition that the integral durability grade is A grade, the integral residual service life is more than or equal to 50 years, and the integral safety degree is more than or equal to 0.5, the tower is judged to be continuously used without maintenance;
if the tower meets any one of the conditions that the integral durability grade is B grade, the integral residual life is a positive number less than 50 years, and the integral safety degree is a positive number less than 0.5, the tower can be continuously used after the tower material is partially replaced;
and if the tower meets any conditions that the integral durability grade is C grade, the integral residual life is less than or equal to 0 year and the integral safety degree is less than or equal to 0, the tower is judged to be required to be disassembled and replaced.
In step B3, the overall durability grade of the tower is the lower of the durability grades of the body layer and the leg connecting layer, wherein the durability grades of the body layer and the leg connecting layer are determined according to the following method:
if the number of the rod pieces with the durability grade of b grade in the layer is not more than 20 percent of the total number of the two types of rod pieces in the layer and no rod pieces with the durability grade of c grade exist, the durability grade of the layer is judged to be A grade;
if the number of the rod pieces with the durability grade of B grade in the layer exceeds 20 percent of the total number of the two types of rod pieces in the layer and no rod pieces with the durability grade of c grade exist, the durability grade of the layer is judged to be B grade;
if the number of the rod pieces with the durability grade of c grade in the layer does not exceed 20 percent of the total number of the two types of rod pieces in the layer, judging that the durability grade of the layer is B grade;
and when the number of the rod pieces with the durability grade of C grade in the layer exceeds 20 percent of the total number of the two types of the rod pieces in the layer, judging that the durability grade of the layer is C grade.
The durability grade judgment standard of the rod piece is as follows:
if the current corrosion thickness of the rod piece is less than 5% of the thickness of the rod piece before corrosion, judging that the durability grade of the rod piece is a grade a;
if the current corrosion thickness of the rod piece is more than 5% of the thickness of the rod piece before corrosion and less than 10% of the thickness of the rod piece before corrosion, judging the durability grade of the rod piece to be b grade;
and if the current corrosion thickness of the rod piece is more than 10% of the thickness of the rod piece before corrosion, judging the durability grade of the rod piece to be grade c.
In the step B3, if the overall durability level, the overall remaining life, and the overall safety of the tower correspond to different maintenance strategies, the maintenance strategy corresponding to the lowest level is used as the final maintenance strategy of the tower.
Compared with the prior art, the invention has the following beneficial effects:
1. the invention relates to a method for evaluating the residual life and the safety of a transmission tower, which comprises the steps of firstly determining the critical corrosion thickness and the current corrosion thickness of each main material rod piece and each diagonal material rod piece in the tower, then calculating the exposure time of the rod piece reaching the critical corrosion thickness and the exposure time corresponding to the current corrosion thickness of the rod piece based on a specific corrosion model, and taking the difference value of the two as the residual life of the rod piece, then sequentially calculating the residual life of the main material rod piece and the diagonal material rod piece of the body layer and the leg connecting layer of the tower, and the residual life of the body layer and the leg connecting layer, and finally obtaining the whole residual life of the tower, and the tower is evaluated in a layering way, so that the effective evaluation of the residual life of the tower is realized, an abnormal rod piece is easy to find, and the maintenance work of maintenance personnel is facilitated. Therefore, the method not only realizes the effective evaluation of the residual life of the tower, but also is convenient for maintenance personnel to carry out maintenance work.
2. According to the method for evaluating the residual life and the safety of the transmission tower, the safety degree parameter and the durability grade are introduced, the rod piece and the whole of the tower are respectively graded in terms of safety degree and durability, and the corresponding maintenance strategy is determined according to the integral durability grade, the integral residual life and the integral safety degree of the tower. Therefore, the method provides decision basis for the transformation or the removal of the old line of the power transmission project.
Drawings
Fig. 1 is a schematic layered diagram of a tower structure.
Detailed Description
The present invention will be described in further detail with reference to specific embodiments.
A method for evaluating the residual life and the safety of a transmission tower comprises the evaluation of the residual life of the tower, and the evaluation of the residual life of the tower sequentially comprises the following steps:
a1, calculating the critical corrosion thickness delta of each main material rod piece and each diagonal material rod piece in the tower lim Thickness delta from the current etching 0 ；
A2, based on the power function corrosion model, dividing the critical corrosion thickness delta lim Substituting the obtained data into the model to calculate the exposure time t of each rod piece to reach the critical corrosion thickness max And the current etching thickness delta 0 Substituting the corrosion model into the model to calculate the exposure time t corresponding to the current corrosion thickness of each rod piece 0 Wherein the power function corrosion model is:
δ＝At n
in the formula, delta is the corrosion thickness, t is the exposure time, A is an initial corrosion rate constant, and n is a development trend constant of the corrosion rate along with the time;
a3, calculating the residual service life t of each rod piece according to the following formula:
t＝t max -t 0 ；
a4, calculating the residual life of the main rod pieces and the diagonal rod pieces of the body layer and the leg connecting layer of the tower by the following formula:
t 1 ＝min(t 1i )i＝1,2,…,n 1
in the above formula, t 1 The remaining life of the main member of the layer, t 1i The remaining life of the ith main bar member of the layer, n 1 Is the total number of main rods in the layer, t 2 The remaining life of the diagonal member of the layer, t 2i The residual life of the ith diagonal member bar of the layer, n 2 The total number of the diagonal member bars in the layer;
a5, determining the residual life of the body layer and the leg connecting layer according to the contribution proportion of various rod pieces in the layer structure, and then determining the whole residual life T of the tower:
T＝min(T i )i＝1,2
in the above formula, T i For the remaining lifetime of the i-th layer structure,
the proportion of the number of the jth rod pieces in the ith layer to the total number of the two rod pieces in the ith layer,
the residual life of the ith layer and the jth rod piece is shown.
In step A1, the critical etching thickness δ lim Thickness delta from the current etching 0 Calculated by the following formula:
δ lim ＝δ s η lim
f yr ＝1-0.9852η
A r ＝0.5η 2 -1.5η+1
m＝r/(f yr A r )
δ 0 ＝δ s -(δ j -δ t )
in the above formula, δ s For the design thickness of the rod, η lim Is the maximum allowable corrosion rate of the rod member, f yr Is the ratio of the yield strength of the rod after corrosion to the yield strength of the rod before corrosion, eta is the corrosion rate of the rod, A r Is the ratio of the cross-sectional area of the rod after etching to the cross-sectional area of the rod before etching, m is the strength reduction coefficient of the rod, r is the stress ratio of the rod, δ j Is the current detected thickness of the rod member, delta t The coating thickness of the rods.
The evaluation method further comprises tower safety evaluation, and the tower safety evaluation sequentially comprises the following steps:
b1, calculating the safety of the main material rod piece and the diagonal material rod piece in the body layer and the leg connecting layer of the tower according to the following formula:
e＝1-δ 0 /δ lim
e 1 ＝min(e 1i )i＝1,2,…,n 1
in the above formula, e is the safety of the rod member, e 1 Safety of the main bar of the layer, e 1i The safety of the ith main bar member of the layer, n 1 Is the total number of main rods in the layer, e 2 Safety of diagonal member for the layer e 2i The safety of the ith diagonal member bar of the layer, n 2 The total number of the diagonal member bars in the layer;
b2, determining the safety degree of the body layer and the leg connecting layer according to the contribution proportion of various rod pieces in the layer structure, and then determining the overall safety degree E of the tower:
E＝min(E i )i＝1,2
in the above formula, E i As a security measure for the i-th layer structure,
the proportion of the number of the jth rod pieces in the ith layer to the total number of the two rod pieces in the ith layer,
the safety degree of the ith layer of the jth rod piece is set;
b3, determining a corresponding maintenance strategy according to the integral durability grade, the integral residual life and the integral safety degree of the tower, specifically:
if the tower meets any condition that the integral durability grade is A grade, the integral residual service life is more than or equal to 50 years, and the integral safety degree is more than or equal to 0.5, the tower is judged to be continuously used without maintenance;
if the tower meets any condition that the integral durability grade is B grade, the integral residual life is a positive number less than 50 years, and the integral safety degree is a positive number less than 0.5, the tower can be continuously used after the tower material is partially replaced;
and if the tower meets any conditions that the integral durability grade is C grade, the integral residual life is less than or equal to 0 year and the integral safety degree is less than or equal to 0, the tower is judged to be required to be disassembled and replaced.
In step B3, the overall durability grade of the tower is the lower one of the durability grades of the body layer and the leg connecting layer, wherein the durability grades of the body layer and the leg connecting layer are determined according to the following method:
if the number of the rod pieces with the durability grade of b grade in the layer is not more than 20 percent of the total number of the two types of rod pieces in the layer and no rod pieces with the durability grade of c grade exist, the durability grade of the layer is judged to be A grade;
if the number of the rod pieces with the durability grade of B grade in the layer exceeds 20 percent of the total number of the two types of rod pieces in the layer and no rod pieces with the durability grade of c grade exist, the durability grade of the layer is judged to be B grade;
if the number of the rod pieces with the durability grade of c grade in the layer does not exceed 20 percent of the total number of the two types of rod pieces in the layer, judging that the durability grade of the layer is B grade;
and when the number of the rod pieces with the durability grade of C grade in the layer exceeds 20 percent of the total number of the two types of the rod pieces in the layer, judging that the durability grade of the layer is C grade.
The durability grade judgment standard of the rod piece is as follows:
if the current corrosion thickness of the rod piece is less than 5% of the thickness of the rod piece before corrosion, judging that the durability grade of the rod piece is a grade a;
if the current corrosion thickness of the rod piece is more than 5% of the thickness of the rod piece before corrosion and less than 10% of the thickness of the rod piece before corrosion, judging the durability grade of the rod piece to be b grade;
and if the current corrosion thickness of the rod piece is more than 10% of the thickness of the rod piece before corrosion, judging the durability grade of the rod piece to be grade c.
In the step B3, if the overall durability level, the overall remaining life, and the overall safety of the tower correspond to different maintenance strategies, the maintenance strategy corresponding to the lowest level is used as the final maintenance strategy of the tower.
The principle of the invention is illustrated as follows:
the pole tower damage is mostly caused by the strength damage of the pole piece, namely, the pole piece reaches the bearing capacity limit state, particularly, the damage state is most easy to occur to the guyed tower with serious corrosion, and the tower material can be corroded and damaged by the environment under the action of the corrosion of the environment when the transmission tower is exposed to the atmospheric environment during operation. Corrosion is one of the important causes of steel structure damage, and not only can influence the structural integrity and safety, but also can reduce the fatigue resistance of the steel structure and shorten the residual life of the structure. The method simulates the atmosphere corrosion rule of steel by constructing a power function corrosion model, determines the residual life of each rod piece in the tower, carries out layered evaluation on the tower according to an analytic hierarchy process, obtains the overall residual life and the safety degree of the tower, and finally provides a maintenance strategy of the tower by combining the overall durability grade of the tower, thereby providing a basis for the detection and safety evaluation work of old towers.
In the power function corrosion model, A and n are dynamic parameters which are mainly related to atmospheric environment, and the values are obtained by fitting according to an atmospheric corrosion test of steel at the position of a tower.
The influence of corrosion on the rod is mainly reflected in two aspects: the loss of cross-sectional area and the degradation of mechanical properties of the material, in the present invention, the maximum allowable corrosion rate eta lim The stress ratio of the corroded rod is equal to the strength reduction coefficient of the rod:
m＝r/(f yr A r )
and during safety evaluation, if the integral durability grade, the integral residual life and the integral safety degree of the tower correspond to different maintenance strategies, taking the maintenance strategy corresponding to the lowest grade as the final maintenance strategy of the tower. For example, the overall durability of the tower is class A (the maintenance strategy corresponding to the index is that the tower can be continuously used without maintenance), the overall residual life is a positive number less than 50 years (the maintenance strategy corresponding to the index is that the tower can be continuously used after the tower material is partially replaced), the overall safety degree is less than or equal to 0 (the maintenance strategy corresponding to the index is that the tower needs to be removed and replaced), and the maintenance strategy corresponding to the overall safety degree is less than or equal to 0 (the tower needs to be removed and replaced) is used as the final maintenance strategy of the tower.
The body layer and the leg connecting layer are obtained by dividing in a sectional mode when iron tower design software SmartTower is used for designing the iron tower. According to the difference of the functions of the rod pieces in the tower, the rod pieces of the tower can be divided into main rod pieces, diagonal rod pieces and auxiliary rod pieces, and the auxiliary rod pieces bear smaller internal force and play a secondary role in the rod pieces, so that the method only evaluates the main rod pieces and the diagonal rod pieces. The layered schematic diagram of the tower structure is shown in fig. 1.
Example 1:
in this embodiment, the remaining life and the safety evaluation are performed by taking a transmission tower in a certain place as an object, and the steps are performed in sequence as follows:
1. calculating the critical corrosion thickness delta of each main material rod piece and each diagonal material rod piece in the tower by the following formula lim And current etch thickness delta 0 And judging the durability grade of the rod piece according to the current corrosion thickness of the rod piece:
δ lim ＝δ s η lim
f yr ＝1-0.9852η
A r ＝0.5η 2 -1.5η+1
m＝r/(f yr A r )
δ 0 ＝δ s -(δ j -δ t )
in the above formula, δ s For the design thickness of the rod, η lim Is the maximum allowable corrosion rate of the rod member, f yr Is the ratio of the yield strength of the rod after corrosion to the yield strength of the rod before corrosion, eta is the corrosion rate of the rod, A r M is the strength reduction coefficient of the rod, 1 is the strength reduction coefficient of the main rod, 0.85 is the strength reduction coefficient of the diagonal rod, r is the stress ratio of the rod, delta j Is the current detected thickness of the rod, delta t The thickness of the coating layer of the rod member;
the durability grade judgment standard of the rod piece is as follows:
if the current corrosion thickness of the rod piece is less than 5% of the thickness of the rod piece before corrosion, judging that the durability grade of the rod piece is a grade a;
if the current corrosion thickness of the rod piece is more than 5% of the thickness of the rod piece before corrosion and less than 10% of the thickness of the rod piece before corrosion, judging the durability grade of the rod piece to be b grade;
if the current corrosion thickness of the rod piece is more than 10% of the thickness of the rod piece before corrosion, judging that the durability grade of the rod piece is grade c;
2. based on the power function corrosion model, the critical corrosion thickness delta is determined lim Substituting the obtained result into the model to calculate the exposure time t of each rod piece to reach the critical corrosion thickness max And the current etching thickness delta 0 Substituting the obtained result into the model to calculate the exposure time t corresponding to the current corrosion thickness of each rod piece 0 Wherein the power function corrosion model is:
δ＝At n
in the above formula, δ is the corrosion thickness, t is the exposure time, a is the initial corrosion rate constant of the location of the tower, the value of which is 0.061mm, and n is the development trend constant of the corrosion rate along with the time, the value of which is 0.57;
3. calculating the residual service life t and the safety degree e of each rod piece according to the following formulas:
t＝t max -t 0 ；
e＝1-δ 0 /δ lim ；
4. calculating the residual life and the safety degree of main material rods and diagonal material rods of a body layer and a leg connecting layer of the tower through the following formulas, wherein the main material rods play a main supporting role, the residual life and the safety degree of the main material rods are determined by the minimum values, and the residual life and the safety degree of the diagonal material rods are determined by the average values:
t 1 ＝min(t 1i )i＝1,2,…,n 1
e 1 ＝min(e 1i )i＝1,2,…,n 1
in the above formula, t 1 The remaining life of the main member of the layer, t 1i For the remaining life of the ith main bar member of the layer, n 1 Is the total number of main rods in the layer, e 1 Safety of the main bar of the layer, e 1i Safety of the ith main bar member of the layer, t 2 The remaining life of the diagonal member of the layer, t 2i The residual life of the ith diagonal member bar of the layer, n 2 Is the total number of diagonal members in the layer, e 2 Safety of diagonal member for the layer e 2i The safety degree of the ith diagonal member bar of the layer is set;
5. determining the residual life and the safety degree of a body layer and a leg connecting layer according to the contribution proportion of various rod pieces in a layer structure, and then determining the whole residual life T and the whole safety degree E of the tower:
T＝min(T i )i＝1,2
E＝min(E i )i＝1,2
in the above formula, T i For the remaining lifetime of the i-th layer structure,
the proportion of the number of the jth rod pieces in the ith layer to the total number of the two rod pieces in the ith layer,
of the i-th layer, the j-th rodResidual life, E i As a security measure for the i-th layer structure,
the safety degree of the ith layer of the jth rod piece is set;
the calculated residual life of the body layer is 34.82 years, the safety degree is 0.45, the residual life of the leg connecting layer is 16.48 years, the safety degree is 0.27, the overall residual life of the tower is 16.48 years, and the safety degree is 0.27;
6. determining a corresponding maintenance strategy according to the integral durability grade, the integral residual life and the integral safety degree of the tower, wherein the method specifically comprises the following steps:
if the tower meets any condition that the integral durability grade is A grade, the integral residual service life is more than or equal to 50 years, and the integral safety degree is more than or equal to 0.5, the tower is judged to be continuously used without maintenance;
if the tower meets any condition that the integral durability grade is B grade, the integral residual life is a positive number less than 50 years, and the integral safety degree is a positive number less than 0.5, the tower can be continuously used after the tower material is partially replaced;
if the tower meets any condition that the integral durability grade is C grade, the integral residual life is less than or equal to 0 year, and the integral safety degree is less than or equal to 0, the tower is judged to be required to be dismantled and replaced;
if the integral durability grade, the integral residual life and the integral safety degree of the tower correspond to different maintenance strategies, taking the maintenance strategy corresponding to the lowest grade as the final maintenance strategy of the tower;
the overall durability grade of the tower is the lower grade of the durability grades of the body layer and the leg connecting layer, and the durability grades of the body layer and the leg connecting layer are determined according to the following method:
if the number of the rod pieces with the durability grade of b grade in the layer is not more than 20 percent of the total number of the two types of rod pieces in the layer and no rod pieces with the durability grade of c grade exist, the durability grade of the layer is judged to be A grade;
if the number of the rod pieces with the durability grade of B grade in the layer exceeds 20 percent of the total number of the two types of rod pieces in the layer and no rod pieces with the durability grade of c grade exist, the durability grade of the layer is judged to be B grade;
if the number of the rod pieces with the durability grade of c grade in the layer does not exceed 20 percent of the total number of the two types of the rod pieces in the layer, the durability grade of the layer is judged to be B grade;
and when the number of the rod pieces with the durability grade of C grade in the layer exceeds 20 percent of the total number of the two types of the rod pieces in the layer, judging that the durability grade of the layer is C grade.
The durability grade of the body layer calculated in this embodiment is a grade a, and the durability grade of the leg connecting layer is a grade B, so that the overall durability grade of the tower is a grade B (the maintenance strategy corresponding thereto is that the tower can be continuously used after the tower material is partially replaced), the overall remaining life is 16.48 years (the maintenance strategy corresponding thereto is that the tower can be continuously used after the tower material is partially replaced), the safety is 0.27 (the maintenance strategy corresponding thereto is that the tower can be continuously used after the tower material is partially replaced), and the final maintenance strategy is: the tower can be continuously used after the tower material is partially replaced.
Claims (5)
1. A method for evaluating the residual life and safety of a transmission tower is characterized by comprising the following steps:
the evaluation method comprises the evaluation of the residual life of the tower, and the evaluation of the residual life of the tower sequentially comprises the following steps:
a1, calculating the critical corrosion thickness delta of each main material rod piece and each diagonal material rod piece in the tower lim With current etch thickness delta 0 ：
δ lim ＝δ s η lim
f yr ＝1-0.9852η
A r ＝0.5η 2 -1.5η+1
m＝r/(f yr A r )
δ 0 ＝δ s -(δ j -δ t )
In the above formula, δ s For the design thickness of the rod, η lim Is the maximum allowable corrosion rate of the rod member, f yr Is the ratio of the yield strength of the rod after corrosion to the yield strength of the rod before corrosion, eta is the corrosion rate of the rod, A r Is a rodThe ratio of the cross-sectional area of the member after etching to that before etching, m is the strength reduction coefficient of the member, r is the stress ratio of the member, δ j Is the current detected thickness of the rod member, delta t The thickness of the coating layer of the rod member;
a2, based on the power function corrosion model, dividing the critical corrosion thickness delta lim Substituting the obtained result into the model to calculate the exposure time t of each rod piece to reach the critical corrosion thickness max And the current etching thickness delta 0 Substituting the obtained result into the model to calculate the exposure time t corresponding to the current corrosion thickness of each rod piece 0 Wherein the power function corrosion model is:
δ＝At n
in the formula, delta is the corrosion thickness, t is the exposure time, A is an initial corrosion rate constant, and n is a development trend constant of the corrosion rate along with the time;
a3, calculating the residual service life t of each rod piece according to the following formula:
t＝t max -t 0 ；
a4, calculating the residual life of the main rod pieces and the diagonal rod pieces of the body layer and the leg connecting layer of the tower by the following formula:
t 1 ＝min(t 1i )i＝1,2,…,n 1
in the above formula, t 1 The remaining life of the main member of the layer, t 1i The remaining life of the ith main bar member of the layer, n 1 Is the total number of main rods in the layer, t 2 The remaining life of the diagonal member of the layer, t 2i For the residual life of the ith diagonal member bar in the layer, n 2 The total number of the diagonal member bars in the layer;
a5, determining the residual life of the body layer and the leg connecting layer according to the contribution proportion of various rod pieces in the layer structure, and then determining the overall residual life T of the pole tower:
T＝min(T i )i＝1,2
in the above formula, T i For the remaining lifetime of the i-th layer structure,
the proportion of the number of the jth rod pieces in the ith layer to the total number of the two rod pieces in the ith layer,
the residual life of the ith layer and the jth rod piece is shown.
2. The method for evaluating the residual life and the safety of the transmission tower according to claim 1, wherein the method comprises the following steps:
the evaluation method further comprises tower safety evaluation, and the tower safety evaluation sequentially comprises the following steps:
b1, calculating the safety of the main material rod piece and the diagonal material rod piece in the body layer and the leg connecting layer of the tower according to the following formula:
e＝1-δ 0 /δ lim
e 1 ＝min(e 1i )i＝1,2,…,n 1
in the above formula, e is the safety of the rod member, e 1 Safety of the main bar of the layer, e 1i The safety of the ith main bar member of the layer, n 1 Is the total number of main rods in the layer, e 2 Safety of diagonal member for the layer e 2i The safety of the ith diagonal member bar of the layer, n 2 The total number of the diagonal member bars in the layer;
b2, determining the safety degree of the body layer and the leg connecting layer according to the contribution proportion of various rod pieces in the layer structure, and then determining the overall safety degree E of the tower:
E＝min(E i )i＝1,2
in the above formula, E i As a security measure for the i-th layer structure,
the proportion of the number of the jth rod pieces in the ith layer to the total number of the two rod pieces in the ith layer,
the safety degree of the ith layer of the jth rod piece is obtained;
b3, determining a corresponding maintenance strategy according to the integral durability grade, the integral residual life and the integral safety degree of the tower, specifically:
if the tower meets any condition that the integral durability grade is A grade, the integral residual service life is more than or equal to 50 years, and the integral safety degree is more than or equal to 0.5, the tower is judged to be continuously used without maintenance;
if the tower meets any one of the conditions that the integral durability grade is B grade, the integral residual life is a positive number less than 50 years, and the integral safety degree is a positive number less than 0.5, the tower can be continuously used after the tower material is partially replaced;
and if the tower meets any conditions that the integral durability grade is C grade, the integral residual life is less than or equal to 0 year and the integral safety degree is less than or equal to 0, the tower is judged to be required to be disassembled and replaced.
3. The method for evaluating the residual life and the safety of the transmission tower according to claim 2, wherein the method comprises the following steps:
in step B3, the overall durability grade of the tower is the lower one of the durability grades of the body layer and the leg connecting layer, wherein the durability grades of the body layer and the leg connecting layer are determined according to the following method:
if the number of the rod pieces with the durability grade of b grade in the layer does not exceed 20 percent of the total number of the two types of the rod pieces in the layer and no rod pieces with the durability grade of c grade exist, the durability grade of the layer is judged to be A grade;
if the number of the rods with the durability grade of B grade in the layer exceeds 20 percent of the total number of the two types of rods in the layer and no rods with the durability grade of c grade exist, judging the durability grade of the layer to be B grade;
if the number of the rod pieces with the durability grade of c grade in the layer does not exceed 20 percent of the total number of the two types of rod pieces in the layer, judging that the durability grade of the layer is B grade;
and when the number of the rod pieces with the durability grade of C grade in the layer exceeds 20 percent of the total number of the two types of the rod pieces in the layer, judging that the durability grade of the layer is C grade.
4. The method for evaluating the residual life and the safety of the transmission tower according to claim 3, wherein the method comprises the following steps:
the durability grade judgment standard of the rod piece is as follows:
if the current corrosion thickness of the rod piece is less than 5% of the thickness of the rod piece before corrosion, judging that the durability grade of the rod piece is a grade a;
if the current corrosion thickness of the rod piece is more than 5% of the thickness of the rod piece before corrosion and less than 10% of the thickness of the rod piece before corrosion, judging the durability grade of the rod piece to be b grade;
and if the current corrosion thickness of the rod piece is more than 10% of the thickness of the rod piece before corrosion, judging the durability grade of the rod piece to be grade c.
5. The method for evaluating the residual life and the safety of the transmission tower according to claim 2, wherein the method comprises the following steps:
in the step B3, if the overall durability level, the overall remaining life, and the overall safety of the tower correspond to different maintenance strategies, the maintenance strategy corresponding to the lowest level is used as the final maintenance strategy of the tower.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010848757.1A CN112069665B (en) | 2020-08-21 | 2020-08-21 | Residual life and safety assessment method for transmission tower |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010848757.1A CN112069665B (en) | 2020-08-21 | 2020-08-21 | Residual life and safety assessment method for transmission tower |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN112069665A CN112069665A (en) | 2020-12-11 |
| CN112069665B true CN112069665B (en) | 2022-09-13 |
Family
ID=73659311
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202010848757.1A Active CN112069665B (en) | 2020-08-21 | 2020-08-21 | Residual life and safety assessment method for transmission tower |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112069665B (en) |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2011058933A (en) * | 2009-09-09 | 2011-03-24 | Mitsubishi Heavy Ind Ltd | Apparatus and method for evaluating remaining life of boiler |
| CN105258737A (en) * | 2015-11-23 | 2016-01-20 | 国家电网公司 | Prediction method for corrosion residual life of transmission line towers at industrial area |
| CN105740546A (en) * | 2016-02-01 | 2016-07-06 | 国家电网公司 | Transmission tower and ground wire security evaluation and service life prediction system based on corrosion state |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104636578B (en) * | 2013-11-11 | 2018-08-14 | 国家电网公司 | A kind of iron tower of power transmission line safety evaluation system and its appraisal procedure |
| CN106529019B (en) * | 2016-11-08 | 2019-04-26 | 国家电网公司华中分部 | A kind of electric power pylon residue lifetime estimation method based on erosion model |
-
2020
- 2020-08-21 CN CN202010848757.1A patent/CN112069665B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2011058933A (en) * | 2009-09-09 | 2011-03-24 | Mitsubishi Heavy Ind Ltd | Apparatus and method for evaluating remaining life of boiler |
| CN105258737A (en) * | 2015-11-23 | 2016-01-20 | 国家电网公司 | Prediction method for corrosion residual life of transmission line towers at industrial area |
| CN105740546A (en) * | 2016-02-01 | 2016-07-06 | 国家电网公司 | Transmission tower and ground wire security evaluation and service life prediction system based on corrosion state |
Non-Patent Citations (1)
| Title |
|---|
| 随机分布多孔板拉伸极限强度的蒙特卡洛有限元分析;谭啸;《中国优秀硕士学位论文全文数据库 基础科学辑》;20170615;A010-25 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN112069665A (en) | 2020-12-11 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN111260183B (en) | Power grid infrastructure project investment plan execution risk assessment system | |
| CN108629491B (en) | Comprehensive evaluation method for maintenance quality of converter transformer | |
| CN110390146B (en) | Method for calculating fatigue damage of welding seam of tower cylinder of wind turbine generator based on sector load and product | |
| CN109978374B (en) | Risk assessment method for oil and gas pipeline system | |
| CN109033615A (en) | Autocrane jib structure methods of risk assessment based on potential failure mode | |
| CN115689114A (en) | Submarine cable running state prediction method based on combined neural network | |
| CN110806191B (en) | Circumferential weld defect pipeline safety evaluation method based on strain monitoring | |
| CN114742415A (en) | Operation effect evaluation method, device and system suitable for charging station | |
| CN105548467A (en) | Tower paint surface corrosion safe state evaluation method | |
| CN112069665B (en) | Residual life and safety assessment method for transmission tower | |
| CN117494950B (en) | Optical storage, filling and inspection micro-grid integrated station operation safety evaluation method | |
| CN114021858A (en) | Refined wind speed prediction method for power transmission line | |
| CN113158484A (en) | Method and system for evaluating stability of transmission tower under geological disaster condition | |
| CN111882238A (en) | Gantry crane structure health assessment method based on cloud model and EAHP | |
| CN117236683A (en) | Power transmission stay wire tower safety evaluation method based on entropy weight-set analysis model | |
| CN116739399A (en) | High-voltage cable running state evaluation method | |
| CN111191360B (en) | Bridge crane metal structure risk assessment method | |
| CN114970273A (en) | Transmission tower strain time sequence prediction and instability early warning method based on ARIMA-LSTM combined model | |
| CN114154221A (en) | Method and system for predicting time-varying reliability of long-span concrete-filled steel tube arch bridge | |
| CN113822538A (en) | AHP-CRITIC-based small and medium-sized earth and rockfill dam operation evaluation method | |
| CN110990916B (en) | Integration method for evaluating and predicting long-term operation safety of dam by considering hysteresis effect | |
| CN111341396A (en) | Method and system for evaluating material corrosion safety in atmospheric environment | |
| CN113505954A (en) | Steel structure building group safety assessment method based on geometric and performance similarity | |
| Marquez-Dominguez et al. | Probabilistic fatigue model for reinforced concrete onshore wind turbine foundations | |
| CN116356894A (en) | Evaluation method suitable for reliability of bearing capacity of transmission tower foundation |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |