CN111965044B - Transmission line creep calculation method and system based on tensile strength loss of lead - Google Patents

Transmission line creep calculation method and system based on tensile strength loss of lead Download PDF

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Publication number
CN111965044B
CN111965044B CN202010830828.5A CN202010830828A CN111965044B CN 111965044 B CN111965044 B CN 111965044B CN 202010830828 A CN202010830828 A CN 202010830828A CN 111965044 B CN111965044 B CN 111965044B
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wire
tensile strength
temperature
composite wire
composite
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CN111965044A (en
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廖如超
李国强
周华敏
周强辅
刘高
缪钟灵
翟瑞聪
郭启迪
陈赟
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Guangdong Power Grid Co Ltd
Machine Inspection Center of Guangdong Power Grid Co Ltd
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Guangdong Power Grid Co Ltd
Machine Inspection Center of Guangdong Power Grid Co Ltd
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
    • G01N3/08—Investigating strength properties of solid materials by application of mechanical stress by applying steady tensile or compressive forces
    • G01N3/18—Performing tests at high or low temperatures
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
    • G01N2203/0014—Type of force applied
    • G01N2203/0016—Tensile or compressive
    • G01N2203/0017—Tensile
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
    • G01N2203/0058—Kind of property studied
    • G01N2203/0069—Fatigue, creep, strain-stress relations or elastic constants
    • G01N2203/0071—Creep
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
    • G01N2203/02—Details not specific for a particular testing method
    • G01N2203/0202—Control of the test
    • G01N2203/0212—Theories, calculations
    • G01N2203/0218—Calculations based on experimental data
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
    • G01N2203/02—Details not specific for a particular testing method
    • G01N2203/022—Environment of the test
    • G01N2203/0222—Temperature
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
    • G01N2203/02—Details not specific for a particular testing method
    • G01N2203/026—Specifications of the specimen
    • G01N2203/0262—Shape of the specimen
    • G01N2203/0278—Thin specimens
    • G01N2203/028—One dimensional, e.g. filaments, wires, ropes or cables
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y04—INFORMATION OR COMMUNICATION TECHNOLOGIES HAVING AN IMPACT ON OTHER TECHNOLOGY AREAS
    • Y04S—SYSTEMS INTEGRATING TECHNOLOGIES RELATED TO POWER NETWORK OPERATION, COMMUNICATION OR INFORMATION TECHNOLOGIES FOR IMPROVING THE ELECTRICAL POWER GENERATION, TRANSMISSION, DISTRIBUTION, MANAGEMENT OR USAGE, i.e. SMART GRIDS
    • Y04S10/00—Systems supporting electrical power generation, transmission or distribution
    • Y04S10/50—Systems or methods supporting the power network operation or management, involving a certain degree of interaction with the load-side end user applications

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  • Physics & Mathematics (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Chemical & Material Sciences (AREA)
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Abstract

According to the creep calculation method and system for the power transmission line based on the loss of the tensile strength of the composite wire, the running temperature of the composite wire and the running time of the corresponding wire after temperature change are predicted through the initial tensile strength of the composite wire and the running temperature of the composite wire in each running time, so that the creep of the composite wire can be obtained after calculation through a creep calculation formula, the working efficiency is effectively improved, and whether the composite wire has risks or not can be judged through a reasonable range of the creep, whether replacement is needed or not is facilitated, and maintenance work of a worker on the composite wire is facilitated.

Description

Transmission line creep calculation method and system based on tensile strength loss of lead
Technical Field
The application relates to the technical field of transmission wires, in particular to a transmission line creep calculation method and system based on the tensile strength loss of the transmission wires.
Background
At present, creep can be generated on the overhead transmission line wire due to tension in the operation process, and the length of the wire can be increased and sag can be increased due to the creep of the wire, so that the transmission quality and safety are affected; moreover, as the wire is operated for a long period of time and at high temperatures, permanent damage to the wire occurs, which can lead to further increases in tensile strength loss and creep of the wire when the wire exceeds its maximum current carrying capacity.
In the prior art, aiming at the problem of creep of the wire, the effect of a plurality of factors is comprehensively considered by means of test analysis, but the creep amount of the wire cannot be accurately obtained, so that whether the wire is at risk or not and whether replacement is needed or not cannot be judged, and the working efficiency is reduced.
Disclosure of Invention
The application aims to at least solve one of the technical defects, in particular to the technical defects that in the prior art, the creep amount of a wire cannot be accurately obtained, so that whether the wire is at risk or not and whether replacement is needed or not cannot be judged, and the working efficiency is reduced.
The embodiment of the application provides a transmission line creep calculation method based on tensile strength loss of a wire, which comprises the following steps:
acquiring tension information and attribute information of a composite wire, and determining the initial tensile strength of the composite wire according to the tension information and the attribute information;
determining the running temperature of the composite wire in each running time, predicting the wire tensile strength loss after temperature change according to the running temperature and the initial tensile strength, and determining the wire running temperature and the wire running time corresponding to the wire tensile strength loss;
and calculating creep of the composite wire through the wire tensile strength loss, the wire running temperature and the wire running time.
Optionally, the tension information includes a tension value corresponding to when the composite wire reaches a tension critical point;
the attribute information comprises the cross-sectional area of the composite wire, the type of the composite wire, the single strand diameter and the strand number corresponding to each type of wire;
the composite wire types include aluminum alloy wires and steel core wires.
Optionally, the step of determining the initial tensile strength of the composite wire according to the tension information and the attribute information includes:
calculating to obtain single-strand initial tensile strength of the composite wire through a corresponding tension value when the composite wire reaches a tension critical point and the cross-sectional area of the composite wire;
and calculating by utilizing the single strand diameters, the strand numbers and the single strand initial tensile strength corresponding to the various types of wires to obtain the initial tensile strength of the aluminum alloy, the initial tensile strength of the steel core and the overall initial tensile strength of the composite wire.
Optionally, the step of determining an operating temperature of the composite conductor during each operating time includes:
acquiring current information and environment information of the composite wire, wherein the environment information comprises solar radiation heat, radiation loss heat dissipation and convection heat dissipation;
and calculating the operation temperature of the composite wire in each operation time according to the current information, the solar radiation heat quantity, the radiation loss heat dissipation and the convection heat dissipation.
Optionally, before the step of predicting the loss of tensile strength of the wire after the temperature change based on the operating temperature and the initial tensile strength, the method further comprises:
determining an original operation temperature sequence corresponding to each operation time according to the operation temperature of the composite wire;
and performing one-time accumulation operation on the original temperature sequence to obtain one-time accumulation temperature sequence, and determining a corresponding wire temperature predicted value according to the one-time accumulation temperature sequence.
Optionally, predicting a wire tensile strength loss after temperature change according to the running temperature and the initial tensile strength, and determining a wire running temperature and a wire running time corresponding to the wire tensile strength loss, including:
calculating according to the wire temperature predicted value, the initial tensile strength of the aluminum alloy, the initial tensile strength of the steel core and the overall initial tensile strength of the composite wire to obtain wire tensile strength loss after temperature change;
and determining the wire running temperatures corresponding to different wire running times according to the wire temperature predicted value.
Optionally, the step of calculating creep of the composite wire from the wire tensile strength loss, the wire operating temperature, and the wire operating time comprises:
and calculating creep deformation of the composite wire at different temperatures according to the tensile strength loss of the wire, the running temperature of the wire and the running time of the wire by utilizing a creep deformation calculation formula of the steel-cored aluminum strand.
The application also provides a transmission line creep calculation system based on the tensile strength loss of the lead, which comprises:
the first confirmation unit is used for acquiring tension information and attribute information of the composite wire and determining the initial tensile strength of the composite wire according to the tension information and the attribute information;
the second confirmation unit is used for determining the running temperature of the composite wire in each running time, predicting the wire tensile strength loss after temperature change according to the running temperature and the initial tensile strength, and determining the wire running temperature and the wire running time corresponding to the wire tensile strength loss;
and the creep calculation unit is used for calculating the creep of the composite wire through the tensile strength loss of the wire, the wire running temperature and the wire running time.
Optionally, the tension information includes a tension value corresponding to when the composite wire reaches a tension critical point;
the attribute information comprises the cross-sectional area of the composite wire, the type of the composite wire, the single strand diameter and the strand number corresponding to each type of wire;
the composite wire types include aluminum alloy wires and steel core wires.
Optionally, the first confirmation unit includes:
the single-strand strength calculation unit is used for calculating the single-strand initial tensile strength of the composite wire through the corresponding tension value and the cross section area of the composite wire when the composite wire reaches the tension critical point;
and the initial strength calculation unit is used for calculating by utilizing the single strand diameters, the strand numbers and the single strand initial tensile strength corresponding to various wires to obtain the initial tensile strength of the aluminum alloy, the initial tensile strength of the steel core and the overall initial tensile strength of the composite wire.
From the above technical solutions, the embodiment of the present application has the following advantages:
according to the transmission line creep calculation method and system based on the loss of the tensile strength of the wire, tension information and attribute information of the composite wire are obtained, and the initial tensile strength of the composite wire is determined according to the tension information and the attribute information; determining the running temperature of the composite wire in each running time, predicting the wire tensile strength loss after temperature change according to the running temperature and the initial tensile strength, and determining the wire running temperature and the wire running time corresponding to the wire tensile strength loss; and calculating creep of the composite wire through the wire tensile strength loss, the wire running temperature and the wire running time.
According to the application, through the initial tensile strength of the composite wire and the running temperature of the composite wire in each running time, the wire tensile strength loss, the wire running temperature and the corresponding wire running time corresponding to the composite wire after temperature change are predicted, so that the creep of the composite wire can be obtained after calculation through a creep calculation formula, the working efficiency is effectively improved, and whether the composite wire has risks or not can be judged through a reasonable creep range, and whether replacement is needed or not is facilitated, so that maintenance work of a worker on the composite wire is facilitated.
Drawings
In order to more clearly illustrate the embodiments of the application or the technical solutions of the prior art, the drawings which are used in the description of the embodiments or the prior art will be briefly described, it being obvious that the drawings in the description below are only some embodiments of the application, and that other drawings can be obtained from these drawings without inventive faculty for a person skilled in the art.
Fig. 1 is a schematic flow chart of a method for calculating creep of a power transmission line based on tensile strength loss of a wire according to an embodiment of the present application;
fig. 2 is a schematic structural diagram of a creep calculation system of a power transmission line based on tensile strength loss of a wire according to an embodiment of the present application;
fig. 3 is a schematic structural diagram of a first confirmation unit according to an embodiment of the present application.
Detailed Description
The following description of the embodiments of the present application will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present application, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the application without making any inventive effort, are intended to be within the scope of the application.
As used herein, the singular forms "a", "an", "the" and "the" are intended to include the plural forms as well, unless expressly stated otherwise, as understood by those skilled in the art. It will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.
It will be understood by those skilled in the art that all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs unless defined otherwise. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the prior art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
Referring to fig. 1, fig. 1 is a schematic flow chart of a method for calculating creep of a power transmission line based on tensile strength loss of a wire according to an embodiment of the present application; as shown in fig. 1, the embodiment of the application provides a transmission line creep calculation method based on tensile strength loss of a wire, which specifically comprises the following steps:
s110: and acquiring tension information and attribute information of the composite wire, and determining the initial tensile strength of the composite wire according to the tension information and the attribute information.
In this step, in order to obtain the initial tensile strength of the composite wire, information about the composite wire, such as tension information including, but not limited to, a stress value of the composite wire in a critical state, and attribute information including, but not limited to, a type of wire, a wire strand number, a single strand diameter, etc. of the composite wire need to be obtained.
It is understood that tensile strength herein refers to the stress value at which a material is at a specified point of state during the entire process of being stretched; taking the composite wire stretching process as an example, when the stress of the material reaches the breaking limit, the breaking limit stress is called tensile limit strength; the composite wire herein refers to a wire structure formed by combining at least two materials.
S120: and determining the running temperature of the composite wire in each running time, predicting the wire tensile strength loss after temperature change according to the running temperature and the initial tensile strength, and determining the wire running temperature and the wire running time corresponding to the wire tensile strength loss.
In this step, since the creep of the composite wire is closely related to the operation time, the operation temperature, the wire stress, etc. of the power transmission line, if the creep of the composite wire is required, it is necessary to obtain the operation temperature of the composite wire in each operation time in advance, and predict the loss of the wire tensile strength after the temperature change by combining the initial tensile strength of the composite wire obtained in step S110.
For example, in the case where the operating temperatures of the composite wire in each of the operating times are known, the operating temperature of the composite wire after the temperature change in each of the operating times may be predicted by a single addition method, and then the wire tensile strength loss of the composite wire including the corresponding wire operating temperature of the composite wire in different wire operating times may be predicted by the predicted operating temperature and the initial tensile strength.
S130: and calculating creep of the composite wire through the wire tensile strength loss, the wire running temperature and the wire running time.
In this step, the creep of the composite wire can be calculated according to the creep prediction equation of the composite wire after the predicted wire tensile strength loss after the temperature change of the composite wire is obtained in step S120 and the wire running temperature and the wire running time corresponding to the wire tensile strength loss are determined.
In the above embodiment, the initial tensile strength of the composite wire and the running temperature of the composite wire in each running time are used for predicting the wire tensile strength loss, the wire running temperature and the corresponding wire running time corresponding to the composite wire after temperature change, so that after calculation by the creep calculation formula, the creep of the composite wire can be obtained, the working efficiency is effectively improved, and whether the composite wire has risks or not can be judged through a reasonable creep range, and whether replacement is needed or not is facilitated, thereby being beneficial to maintenance work of workers on the composite wire.
In one embodiment, the tension information may include a tension value corresponding to when the composite wire reaches a tension critical point; the attribute information may include a cross-sectional area of the composite wire, a type of the composite wire, a single strand diameter and a number of strands corresponding to each type of wire; the composite wire types may include aluminum alloy wires and steel core wires.
In one embodiment, the step of determining the initial tensile strength of the composite wire according to the tension information and the attribute information in the step S110 may include:
s111: calculating to obtain single-strand initial tensile strength of the composite wire through a corresponding tension value when the composite wire reaches a tension critical point and the cross-sectional area of the composite wire;
s112: and calculating by utilizing the single strand diameters, the strand numbers and the single strand initial tensile strength corresponding to the various types of wires to obtain the initial tensile strength of the aluminum alloy, the initial tensile strength of the steel core and the overall initial tensile strength of the composite wire.
In this embodiment, the single-strand initial tensile strength of the composite wire may be calculated from a tensile value corresponding to the composite wire when the composite wire reaches the tensile critical point and a cross-sectional area of the composite wire, if the tensile value corresponding to the composite wire when the composite wire reaches the tensile critical point is F and the cross-sectional area of the composite wire is L, the single-strand initial tensile strength S of the composite wire is:
when the single-strand initial tensile strength of the composite wire is obtained, if the initial tensile strength corresponding to each component in the composite wire and the overall initial tensile strength of the composite wire are required to be calculated, the component types of the composite wire, the number of strands and the single-strand diameter corresponding to the component types are required to be obtained, and the single-strand initial tensile strength obtained by calculation is used for calculation.
For example, when the composite wire is a steel-cored aluminum strand composed of an aluminum alloy wire and a steel-cored wire, the initial tensile strength of the aluminum alloy and the initial tensile strength of the steel core can be calculated, respectively, and then the overall initial tensile strength of the composite wire can be calculated as follows:
wherein d Al 、d St The diameters of the single-strand wires of the aluminum alloy and the steel core are respectively S Al 、S St Single strand initial tensile strength, n, of aluminum alloy, steel core, respectively Al 、n St The wire strand numbers of the aluminum alloy and the steel core are respectively STR Al 、STR St 、STR T The initial tensile strength of the aluminum alloy, the initial tensile strength of the steel core and the overall initial tensile strength of the composite wire are respectively.
In one embodiment, the step of determining the operating temperature of the composite wire in each operating time in step S120 may include:
s121: acquiring current information and environment information of the composite wire, wherein the environment information comprises solar radiation heat, radiation loss heat dissipation and convection heat dissipation;
s122: and calculating the operation temperature of the composite wire in each operation time according to the current information, the solar radiation heat quantity, the radiation loss heat dissipation and the convection heat dissipation.
In this embodiment, in order to obtain the operating temperature of the composite wire in each operating time, the environmental information and the current information of the composite wire may be obtained first, and then the operating temperature of the power transmission line may be obtained according to a thermal equilibrium equation, where the thermal equilibrium equation is as follows:
q s -q r -q c +I 2 R(T c )＝0
wherein q s Q is the heat of solar radiation r For radiation loss and heat dissipation, q c To dissipate heat by convection, I 2 R(T c ) Is joule heating of the composite wire.
When the joule heating of the composite conductor is obtained, the operating temperature of the composite conductor during each operating time can be determined.
In one embodiment, before the step of predicting the loss of the tensile strength of the wire after the temperature change according to the operation temperature and the initial tensile strength in the step S120, the method may further include:
s123: determining an original operation temperature sequence corresponding to each operation time according to the operation temperature of the composite wire;
s124: and performing one-time accumulation operation on the original temperature sequence to obtain one-time accumulation temperature sequence, and determining a corresponding wire temperature predicted value according to the one-time accumulation temperature sequence.
In this embodiment, before predicting the loss of tensile strength of the wire after the temperature change, the wire running temperature of the composite wire after the temperature change in the wire running time may be predicted, and the wire running temperature may be obtained by performing an accumulation operation on the original running temperature sequence.
For example, in the present application, where the operating temperatures for all of the operating times of the composite conductor are known, the original operating temperature sequence corresponding to each operating time may be determined as follows:
q (0) ＝{q (0) (1),q (0) (2),...,q (0) (n)}
wherein q (0) Is the original operation temperature sequence under all operation time, n is the number of sequence values, q (0) (n) is the operating temperature sequence value corresponding to the nth operating hour.
Through one accumulation operation, the obtained one accumulation temperature sequence is as follows:
q (1) ＝q (0) d{q (1) (1),q (1) (2),...,q (1) (n)}
wherein q (1) Is a primary accumulation temperature sequence, d is a primary accumulation generating operator, q (1) (n) is the operational temperature sequence value accumulated once for the nth operational hour, i.e. the wire temperature predicted value.
For the one-time accumulation generating operator d, the conversion formula is as follows:
for one accumulated temperature sequence q (1) The predicted value of the one-time accumulation generated sequence can be obtained by the calculation method, and is expressed asThe predicted value of the original running temperature sequence is obtained by one-time accumulation and reduction of the wire temperature predicted value of one-time accumulation temperature sequence, and the formula is as follows:
in one embodiment, the step of predicting the loss of tensile strength of the wire after the temperature change according to the operation temperature and the initial tensile strength in step S120, and determining the operation temperature of the wire and the operation time of the wire corresponding to the loss of tensile strength of the wire may include:
s125: calculating according to the wire temperature predicted value, the initial tensile strength of the aluminum alloy, the initial tensile strength of the steel core and the overall initial tensile strength of the composite wire to obtain wire tensile strength loss after temperature change;
s126: and determining the wire running temperatures corresponding to different wire running times according to the wire temperature predicted value.
In this embodiment, after obtaining the predicted value of the wire temperature, the initial tensile strength of the aluminum alloy, the initial tensile strength of the steel core, and the overall initial tensile strength of the composite wire, the wire tensile strength loss of the steel core aluminum wire after the temperature change can be calculated according to the tensile strength empirical loss formula, where the formula is as follows:
wherein, RS Al Is the percentage of the residual strength of the aluminum alloy in the initial tensile strength, RS COM Is the percentage of the composite wire remaining strength in the initial tensile strength, T is the wire run temperature, and T is the wire run time.
In one embodiment, the step of calculating creep of the composite wire through the wire tensile strength loss, the wire operating temperature, and the wire operating time in step S130 may include:
and calculating creep deformation of the composite wire at different temperatures according to the tensile strength loss of the wire, the running temperature of the wire and the running time of the wire by utilizing a creep deformation calculation formula of the steel-cored aluminum strand.
In this embodiment, since the creep of the power transmission line is closely related to the running time, temperature and wire stress of the line, the creep of the composite wire can be calculated according to the creep prediction equation of the composite wire.
For all aluminum wire (AAC), the creep calculation formula at ambient temperature is:
ε＝Kσ 1.3 t 0.16
where ε is the initial wire creep, K is a constant, σ is the wire stress, and t is the number of operating hours of the wire.
For a steel-cored aluminum strand (ACSR), the creep calculation formula at ambient temperature is:
ε＝2.4(RS％) 1.3 t 0.16
wherein epsilon is creep of the composite wire, RS% is wire tensile strength loss of the composite wire, and t is wire running time of the composite wire.
For all-aluminum wire (AAC), the creep calculation formula at high temperature is:
ε＝MT 1.4 σ 1.3 t 0.16
wherein T is the running temperature of the wire, M is a constant, and the values of K and M are shown in the following table:
constant (constant) 7 strands of 19 strands of 37 strands of 61 strands
K 0.84 0.77 0.77 0.71
M 0.0090 0.0090 0.0084 0.0077
For steel-cored aluminum strand (ACSR), the creep calculation formula at high temperature is:
ε＝0.24(RS％)Tt 0.16
wherein epsilon is creep of the composite wire, RS% is wire tensile strength loss of the composite wire, T is wire running temperature of the composite wire, and T is wire running time of the composite wire.
In one embodiment, as shown in fig. 2, fig. 2 is a schematic structural diagram of a creep calculation system of a power transmission line based on a loss of tensile strength of a wire, and the present application further provides a creep calculation system of a power transmission line based on a loss of tensile strength of a wire, including a first confirmation unit 110, a first confirmation unit 120, and a creep calculation unit 130, which specifically includes:
a first confirmation unit 110, configured to obtain tension information and attribute information of a composite wire, and determine an initial tensile strength of the composite wire according to the tension information and the attribute information;
a second confirmation unit 120, configured to determine an operation temperature of the composite wire in each operation time, predict a wire tensile strength loss after temperature change according to the operation temperature and the initial tensile strength, and determine a wire operation temperature and a wire operation time corresponding to the wire tensile strength loss;
and a creep calculation unit 130 for calculating creep of the composite wire through the wire tensile strength loss, the wire operating temperature, and the wire operating time.
In the above embodiment, the initial tensile strength of the composite wire and the running temperature of the composite wire in each running time are used for predicting the wire tensile strength loss, the wire running temperature and the corresponding wire running time corresponding to the composite wire after temperature change, so that after calculation by the creep calculation formula, the creep of the composite wire can be obtained, the working efficiency is effectively improved, and whether the composite wire has risks or not can be judged through a reasonable creep range, and whether replacement is needed or not is facilitated, thereby being beneficial to maintenance work of workers on the composite wire.
In one embodiment, the tension information in the first confirmation unit 110 may include a tension value corresponding to when the composite wire reaches a tension critical point; the attribute information may include a cross-sectional area of the composite wire, a type of the composite wire, a single strand diameter and a number of strands corresponding to each type of wire; the composite wire types may include aluminum alloy wires and steel core wires.
In one embodiment, as shown in fig. 3, fig. 3 is a schematic structural diagram of a first confirmation unit provided in the present application, and the first confirmation unit 110 may include:
a single-strand strength calculation unit 111, configured to calculate, according to a tension value corresponding to the composite wire when the composite wire reaches a tension critical point and a cross-sectional area of the composite wire, a single-strand initial tensile strength of the composite wire;
the initial strength calculating unit 112 is configured to calculate, by using the single strand diameters and the number of strands corresponding to the various types of wires and the single strand initial tensile strength, an aluminum alloy initial tensile strength, a steel core initial tensile strength, and an overall initial tensile strength of the composite wire.
The above embodiments are only for illustrating the technical solution of the present application, and not for limiting the same; although the application has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims (9)

1. The transmission line creep calculation method based on the tensile strength loss of the lead is characterized by comprising the following steps of:
acquiring tension information and attribute information of a composite wire, and determining the initial tensile strength of the composite wire according to the tension information and the attribute information;
determining the running temperature of the composite wire in each running time, predicting the wire tensile strength loss after temperature change according to the running temperature and the initial tensile strength, and determining the wire running temperature and the wire running time corresponding to the wire tensile strength loss;
calculating creep of the composite wire from the wire tensile strength loss, the wire operating temperature, and the wire operating time, comprising:
according to an empirical loss formula of tensile strength, the tensile strength loss of the steel-cored aluminum conductor after temperature change is calculated, wherein the formula is as follows:
wherein, RS Al Is the percentage of the residual strength of the aluminum alloy in the initial tensile strength, RS COM Is the percentage of the residual strength of the composite wire in the initial tensile strength, T is the wire operating temperature, T is the wire operating time, STR Al 、STR St 、STR T The initial tensile strength of the aluminum alloy, the initial tensile strength of the steel core and the overall initial tensile strength of the composite wire are respectively;
calculating creep of the composite wire at different temperatures according to the tensile strength loss of the wire, the running temperature of the wire and the running time of the wire by utilizing a creep calculation formula of the steel-cored aluminum strand;
for all aluminum wire (AAC), the creep calculation formula at ambient temperature is:
ε＝Kσ 1.3 t 0.16
where ε is the initial wire creep, K is a constant, σ is the wire stress, and t is the number of operating hours of the wire;
for a steel-cored aluminum strand (ACSR), the creep calculation formula at ambient temperature is:
ε＝2.4(RS％) 1.3 t 0.16
wherein epsilon is creep of the composite wire, RS% is wire tensile strength loss of the composite wire, and t is wire running time of the composite wire;
for all-aluminum wire (AAC), the creep calculation formula at high temperature is:
ε＝MT 1.4 σ 1.3 t 0.16
wherein T is the running temperature of the lead, and M is a constant;
for steel-cored aluminum strand (ACSR), the creep calculation formula at high temperature is:
ε＝0.24(R S％)Tt 0.16
wherein epsilon is creep of the composite wire, RS% is wire tensile strength loss of the composite wire, T is wire running temperature of the composite wire, and T is wire running time of the composite wire.
2. The transmission line creep calculation method based on the loss of tensile strength of a wire according to claim 1, wherein the tension information includes a tension value corresponding to when the composite wire reaches a tension critical point;
the attribute information comprises the cross-sectional area of the composite wire, the type of the composite wire, the single strand diameter and the strand number corresponding to each type of wire;
the composite wire types include aluminum alloy wires and steel core wires.
3. The method of calculating creep of a power transmission line based on loss of tensile strength of a wire according to claim 2, wherein the step of determining the initial tensile strength of the composite wire based on the tension information and the attribute information includes:
calculating to obtain single-strand initial tensile strength of the composite wire through a corresponding tension value when the composite wire reaches a tension critical point and the cross-sectional area of the composite wire;
and calculating by utilizing the single strand diameters, the strand numbers and the single strand initial tensile strength corresponding to the various types of wires to obtain the initial tensile strength of the aluminum alloy, the initial tensile strength of the steel core and the overall initial tensile strength of the composite wire.
4. The method of transmission line creep calculation based on loss of tensile strength of a conductor according to claim 1, wherein the step of determining the operating temperature of the composite conductor during each operating time comprises:
acquiring current information and environment information of the composite wire, wherein the environment information comprises solar radiation heat, radiation loss heat dissipation and convection heat dissipation;
and calculating the operation temperature of the composite wire in each operation time according to the current information, the solar radiation heat quantity, the radiation loss heat dissipation and the convection heat dissipation.
5. The method for calculating creep of a power transmission line based on a loss of tensile strength of a wire according to claim 3, further comprising, before the step of predicting a loss of tensile strength of a wire after temperature change based on the operating temperature and the initial tensile strength:
determining an original operation temperature sequence corresponding to each operation time according to the operation temperature of the composite wire;
and performing one-time accumulation operation on the original temperature sequence to obtain one-time accumulation temperature sequence, and determining a corresponding wire temperature predicted value according to the one-time accumulation temperature sequence.
6. The method of calculating creep of a power transmission line based on a loss of tensile strength of a wire according to claim 5, wherein predicting the loss of tensile strength of the wire after temperature change according to the operating temperature and the initial tensile strength, and determining a wire operating temperature and a wire operating time corresponding to the loss of tensile strength of the wire, comprises:
calculating according to the wire temperature predicted value, the initial tensile strength of the aluminum alloy, the initial tensile strength of the steel core and the overall initial tensile strength of the composite wire to obtain wire tensile strength loss after temperature change;
and determining the wire running temperatures corresponding to different wire running times according to the wire temperature predicted value.
7. A transmission line creep calculation system based on loss of tensile strength of a wire, comprising:
the first confirmation unit is used for acquiring tension information and attribute information of the composite wire and determining the initial tensile strength of the composite wire according to the tension information and the attribute information;
the second confirmation unit is used for determining the running temperature of the composite wire in each running time, predicting the wire tensile strength loss after temperature change according to the running temperature and the initial tensile strength, and determining the wire running temperature and the wire running time corresponding to the wire tensile strength loss;
a creep calculation unit for calculating creep of the composite wire from the wire tensile strength loss, the wire operating temperature, and the wire operating time, comprising:
according to an empirical loss formula of tensile strength, the tensile strength loss of the steel-cored aluminum conductor after temperature change is calculated, wherein the formula is as follows:
wherein, RS Al Is the percentage of the residual strength of the aluminum alloy in the initial tensile strength, RS COM Is the percentage of the residual strength of the composite wire in the initial tensile strength, T is the wire operating temperature, T is the wire operating time, STR Al 、STR St 、STR T The initial tensile strength of the aluminum alloy, the initial tensile strength of the steel core and the overall initial tensile strength of the composite wire are respectively;
calculating creep of the composite wire at different temperatures according to the tensile strength loss of the wire, the running temperature of the wire and the running time of the wire by utilizing a creep calculation formula of the steel-cored aluminum strand;
for all aluminum wire (AAC), the creep calculation formula at ambient temperature is:
ε＝Kσ 1.3 t 0.16
where ε is the initial wire creep, K is a constant, σ is the wire stress, and t is the number of operating hours of the wire;
for a steel-cored aluminum strand (ACSR), the creep calculation formula at ambient temperature is:
ε＝2.4(RS％) 1.3 t 0.16
wherein epsilon is creep of the composite wire, RS% is wire tensile strength loss of the composite wire, and t is wire running time of the composite wire;
for all-aluminum wire (AAC), the creep calculation formula at high temperature is:
ε＝MT 1.4 σ 1.3 t 0.16
wherein T is the running temperature of the lead, and M is a constant;
for steel-cored aluminum strand (ACSR), the creep calculation formula at high temperature is:
ε＝0.24(RS％)Tt 0.16
wherein epsilon is creep of the composite wire, RS% is wire tensile strength loss of the composite wire, T is wire running temperature of the composite wire, and T is wire running time of the composite wire.
8. The transmission line creep calculation system based on loss of tensile strength of a wire according to claim 7, wherein the tension information includes a corresponding tension value when the composite wire reaches a tension critical point;
the attribute information comprises the cross-sectional area of the composite wire, the type of the composite wire, the single strand diameter and the strand number corresponding to each type of wire;
the composite wire types include aluminum alloy wires and steel core wires.
9. The transmission line creep calculation system based on loss of tensile strength of a wire according to claim 8, wherein the first confirmation unit comprises:
the single-strand strength calculation unit is used for calculating the single-strand initial tensile strength of the composite wire through the corresponding tension value and the cross section area of the composite wire when the composite wire reaches the tension critical point;
and the initial strength calculation unit is used for calculating by utilizing the single strand diameters, the strand numbers and the single strand initial tensile strength corresponding to various wires to obtain the initial tensile strength of the aluminum alloy, the initial tensile strength of the steel core and the overall initial tensile strength of the composite wire.
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