CN110095697B - Cable current-carrying capacity adjusting method, device, equipment and readable storage medium - Google Patents
Cable current-carrying capacity adjusting method, device, equipment and readable storage medium Download PDFInfo
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- CN110095697B CN110095697B CN201910516228.9A CN201910516228A CN110095697B CN 110095697 B CN110095697 B CN 110095697B CN 201910516228 A CN201910516228 A CN 201910516228A CN 110095697 B CN110095697 B CN 110095697B
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- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/08—Locating faults in cables, transmission lines, or networks
- G01R31/081—Locating faults in cables, transmission lines, or networks according to type of conductors
- G01R31/083—Locating faults in cables, transmission lines, or networks according to type of conductors in cables, e.g. underground
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- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/08—Locating faults in cables, transmission lines, or networks
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Abstract
The invention discloses a method for adjusting the current-carrying capacity of a cable, which comprises the following steps: acquiring the current-carrying capacity of a target cable, and taking the acquired current-carrying capacity as a reference current-carrying capacity; determining temperature change data of a target cable under a specified laying mode according to the reference current-carrying capacity; carrying out thermal cycle test on the cable insulation of the target cable according to the temperature change rule corresponding to each specified laying mode; analyzing the insulation performance of the cable insulation subjected to the thermal cycle test to obtain test insulation performance data; analyzing the current-carrying capacity fluctuation conditions of the cable in different laying modes according to the tested insulation performance data and the original insulation performance data to generate cable current-carrying capacity fluctuation data; adjusting the current-carrying capacity of the target cable according to preset adjustment rules according to the cable current-carrying capacity fluctuation data; the method can improve the adjustment precision of the current-carrying capacity of the cable; the invention also discloses a cable current-carrying capacity adjusting device, equipment and a readable storage medium, and the cable current-carrying capacity adjusting device, equipment and readable storage medium have the beneficial effects.
Description
Technical Field
The invention relates to the technical field of insulation thermal cycle of a crosslinked polyethylene cable, in particular to a method, a device, equipment and a readable storage medium for adjusting the current-carrying capacity of the cable.
Background
The domestic and foreign standards generally consider the influence of a laying mode on the current-carrying capacity on the basis of basic current-carrying capacity when calculating the current-carrying capacity of the cable, and basically follow the mode that room temperature is used as initial temperature, the long-term normal operation working temperature of the cable is 90 ℃ used as final steady-state temperature, the corresponding maximum current is obtained through a thermal circuit method, simulation software and the like, and the adjustment is carried out according to the current waiting value.
The cable is assumed to be in an ideal operation state by the adjusting mode, and actually, the current-carrying capacity of the cable is fluctuated rather than constant and is also influenced by a plurality of factors, so that the method for calculating the current-carrying capacity has great restriction and low evaluation precision, so that the current-carrying capacity adjustment cannot be fit with the actual situation, and the normal operation of the cable is influenced.
Therefore, how to improve the accuracy of adjusting the current-carrying capacity of the cable is a technical problem to be solved by those skilled in the art.
Disclosure of Invention
The invention aims to provide a method for adjusting the current-carrying capacity of a cable, which can improve the accuracy of adjusting the current-carrying capacity of the cable; another object of the present invention is to provide a cable ampacity adjustment device, a cable ampacity adjustment apparatus, and a readable storage medium.
In order to solve the technical problem, the invention provides a method for adjusting the current-carrying capacity of a cable, which comprises the following steps:
acquiring the current-carrying capacity of a target cable, and taking the acquired current-carrying capacity as a reference current-carrying capacity;
determining temperature change data of the target cable in a specified laying mode according to the reference current-carrying capacity;
carrying out thermal cycle test on the cable insulation of the target cable according to the temperature change rule corresponding to each specified laying mode; the temperature change rule corresponding to the specified laying mode is matched with the temperature change data corresponding to the specified laying mode;
analyzing the insulation performance of the cable insulation subjected to the thermal cycle test to obtain test insulation performance data;
analyzing the current-carrying capacity fluctuation conditions of the cable in different laying modes according to the test insulation performance data and the original insulation performance data to generate cable current-carrying capacity fluctuation data; wherein the original insulation performance data is the insulation performance data of the original cable insulation which is not subjected to the thermal cycle test;
and adjusting the current-carrying capacity of the target cable according to the cable current-carrying capacity fluctuation data and preset adjustment rules.
Optionally, the insulation performance analysis of the cable insulation subjected to the thermal cycle test includes:
performing physical and chemical analysis, electrical analysis and mechanical performance analysis on the cable insulation subjected to the thermal cycle test;
wherein the physicochemical analysis comprises: analyzing microstructure and aggregation state structure;
the electrical analysis comprises: analyzing four parameters of dielectric constant, dielectric loss, conductivity and breakdown field intensity of the dielectric medium;
the mechanical property analysis comprises: and (5) analyzing the mechanical external characteristics.
Optionally, determining temperature change data of the target cable in the specified laying mode according to the reference ampacity includes:
determining cable models of the target cable in different laying modes;
and inputting the reference current-carrying capacity into the cable model to obtain a temperature rise curve and a temperature drop curve of the target cable under different laying modes, taking the temperature rise curve as temperature rise change data in the temperature change data, and taking the temperature drop curve as temperature drop change standard data in the temperature change data.
Optionally, performing a thermal cycle test on the cable insulation of the target cable according to the temperature change rule corresponding to each of the specified laying modes, including:
and calling a programmable temperature control aging box to carry out temperature rise and temperature drop heat circulation tests on each cable insulation group according to a preset temperature rise and drop rate regulating mechanism.
Optionally, adjusting the current-carrying capacity of the target cable according to the cable current-carrying capacity fluctuation data and a preset adjustment rule, including:
acquiring insulation performance variable quantity according to the cable current-carrying capacity fluctuation data;
judging whether the insulation performance variation reaches a preset variation threshold value;
when the current-carrying capacity reaches the standard current-carrying capacity, the current-carrying capacity is adjusted downwards on the basis of the standard current-carrying capacity;
and when the current-carrying capacity does not reach the standard current-carrying capacity, adjusting the current-carrying capacity on the basis of the standard current-carrying capacity.
Optionally, the obtaining the current-carrying capacity of the target cable includes:
and acquiring an input current effective value corresponding to the target cable when the conductor reaches 90 ℃, and taking the input current effective value as the reference current-carrying capacity.
Optionally, the obtaining the current-carrying capacity of the target cable includes:
and acquiring the current carrying capacity of the target cable in the air domain.
The invention discloses a cable current-carrying capacity adjusting device, comprising:
the reference current-carrying capacity obtaining unit is used for obtaining the current-carrying capacity of the target cable and taking the obtained current-carrying capacity as the reference current-carrying capacity;
the change standard determining unit is used for determining temperature change data under different laying modes according to the reference current-carrying capacity;
the thermal cycle test unit is used for performing thermal cycle test on the cable insulation of the target cable according to the temperature change rule corresponding to each specified laying mode; the temperature change rule corresponding to the specified laying mode is matched with the temperature change data corresponding to the specified laying mode; the insulation performance analysis unit is used for carrying out insulation performance analysis on the cable insulation subjected to the thermal cycle test to obtain test insulation performance data;
the flow fluctuation analysis unit is used for analyzing the cable current-carrying capacity fluctuation conditions in different laying modes according to the test insulation performance data and the original insulation performance data to generate cable current-carrying capacity fluctuation data; wherein the original insulation performance data is the insulation performance data of the original cable insulation which is not subjected to the thermal cycle test;
and the current-carrying capacity adjusting unit is used for adjusting the current-carrying capacity of the target cable according to the cable current-carrying capacity fluctuation data and preset adjusting rules. The invention discloses a cable current-carrying capacity adjusting device, which comprises:
a memory for storing a program;
and the processor is used for realizing the steps of the cable current-carrying capacity adjusting method when the program is executed.
The invention discloses a readable storage medium, wherein a program is stored on the readable storage medium, and the program realizes the steps of the cable current-carrying capacity adjusting method when being executed by a processor.
The invention provides a method for adjusting the current-carrying capacity of a cable, which comprises the following steps: acquiring the current-carrying capacity of a target cable, and taking the acquired current-carrying capacity as a reference current-carrying capacity; determining temperature change data of a target cable under a specified laying mode according to the reference current-carrying capacity; carrying out thermal cycle test on the cable insulation of the target cable according to the temperature change rule corresponding to each specified laying mode; the temperature change rule corresponding to the specified laying mode is matched with the temperature change data corresponding to the specified laying mode; analyzing the insulation performance of the cable insulation subjected to the thermal cycle test to obtain test insulation performance data; analyzing the current-carrying capacity fluctuation conditions of the cable in different laying modes according to the tested insulation performance data and the original insulation performance data to generate cable current-carrying capacity fluctuation data; the original insulation performance data is insulation performance data of original cable insulation without thermal cycle test; and adjusting the current-carrying capacity of the target cable according to the preset adjustment rule according to the cable current-carrying capacity fluctuation data.
The method evaluates the current-carrying capacity on the basis of the influence of different heating and cooling processes of a cable operation process on the insulation of a specific cable under different laying modes, intuitively studies the influence of the temperature change caused by different laying modes on the performance of an insulating material from the perspective of the insulation nature of XLPE (cross-linked polyethylene), namely determines the performance of the material by comparing the change of an internal aggregation state structure of the material caused by the gradient of different long-term heating and cooling curves, considers the heat resistance of the cross-linked polyethylene material, simultaneously considers the influence of the internal heating and cooling processes of the cable on the insulation, the change of the internal aggregation state structure before and after insulation aging and other factors, determines the fluctuation data of the current-carrying capacity of the cable through comprehensive analysis, and can realize the optimal current-carrying capacity adjustment on the premise of ensuring the better performance of the cable insulation according to the adjustment of the data.
The invention also discloses a cable current-carrying capacity adjusting device, equipment and a readable storage medium, which have the beneficial effects and are not described herein again.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.
Fig. 1 is a flowchart of a method for adjusting a current-carrying capacity of a cable according to an embodiment of the present invention;
fig. 2 is a schematic flow chart of a method for adjusting a current-carrying capacity of a cable according to an embodiment of the present invention;
fig. 3 is a block diagram of a structure of a cable ampacity adjustment device according to an embodiment of the present invention;
fig. 4 is a block diagram of a structure of a cable current-carrying capacity adjusting apparatus according to an embodiment of the present invention;
fig. 5 is a schematic structural diagram of a cable current-carrying capacity adjustment device according to an embodiment of the present invention.
Detailed Description
The core of the invention is to provide a method for adjusting the current-carrying capacity of a cable, which can improve the accuracy of adjusting the current-carrying capacity of the cable; the invention also provides a cable current-carrying capacity adjusting device, equipment and a readable storage medium.
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
At present, the influence caused by a laying mode is considered in calculating the current-carrying capacity of the cable, the method is basically followed by taking room temperature as initial temperature and taking the long-term normal operation working temperature of the cable as final steady-state temperature, and the corresponding maximum current is obtained through a thermal circuit method, simulation software and the like.
To a great extent, the methods do not take the heat resistance of the crosslinked polyethylene material into consideration, and further do not take the influences of factors such as the influence of the temperature rise and reduction process inside the cable on insulation, the difference before and after insulation aging and the like into consideration, and the factors can change the internal aggregation state structure to change the thermal resistance and the thermal capacity of the XLPE insulation, so that the current-carrying capacity of the cable can be considered to be fluctuated rather than constant, and therefore, the method for calculating the current-carrying capacity has great restriction.
The optimal current-carrying capacity is analyzed from the perspective of the cable laying mode, different heating and cooling processes of the cable exist under the condition that the same current is introduced to the cable due to the difference of external environments of actual running cables with different laying modes, different heating rates and different cooling rates have different degrees of influence on the aggregation state structure of the cable insulation, and the physical, chemical, electrical and mechanical properties of the insulation material are changed.
The method provided by the invention evaluates the current-carrying capacity on the basis of the influence of different heating and cooling processes of different laying modes on the insulation of a specific cable in the cable running process, intuitively studies the influence of the temperature change caused by different laying modes on the performance of an insulating material from the angle of the insulation nature of the XLPE of the cable, namely determines the performance of the material by comparing the change of an internal aggregation state structure of the material caused by the gradient of different long-term heating and cooling curves, overcomes the defect that the difference, the temperature rise and the temperature reduction rate of the cable insulation are neglected in the conventional calculation of the current-carrying capacity on the influence of the difference, the temperature rise and the temperature reduction rate on the XLPE of the semi-crystalline polymer, analyzes the change of the insulation performance caused by different laying modes from the angle of the XLPE insulation, and can ensure the better.
The first embodiment is as follows:
referring to fig. 1, fig. 1 is a flowchart of a method for adjusting a current-carrying capacity of a cable according to the present embodiment; the method can comprise the following steps:
and step s110, obtaining the current-carrying capacity of the target cable, and taking the obtained current-carrying capacity as the reference current-carrying capacity.
Firstly, selecting a target cable (the invention is mainly based on an XLPE power cable), determining the specification, and obtaining the reference current-carrying capacity I of the cable through actual measurementBPreferably, in order to simplify the implementation process, the target cable may be directly acquiredCurrent carrying capacity under air domain.
In addition, in this embodiment, the collection state is not limited, the current-carrying capacity at normal temperature and the like may be directly obtained, and in order to obtain the optimal reference current-carrying capacity, the input current effective value corresponding to the target cable when the conductor reaches 90 ℃ may be obtained, and the input current effective value is used as the reference current-carrying capacity.
Specifically, the process of obtaining the current-carrying capacity of the target cable may specifically be: the current-carrying capacity of the XLPE cable with the determined specification in the air domain is the effective value of the corresponding input current when the conductor reaches 90 ℃, and is named as reference current-carrying capacity IB。
And step s120, determining temperature change data of the target cable under the specified laying mode according to the reference current-carrying capacity.
Different heating and cooling processes of cables in the operation of different laying modes under the condition of same current are caused by the difference of external environments, and different heating rates and cooling rates can influence the insulated aggregation state structure of the cables, so that the operation performance of the cables is further influenced. The purpose of this step is to determine the temperature change of the cable over time in different laying modes, so that the performance change of the cable insulation can be further determined according to the temperature change data.
The temperature change data mainly comprises temperature rise change data and temperature drop change data, the temperature rise change data refers to data that the temperature of a target cable is increased along with the time under the specified laying state, the temperature drop change data refers to data that the temperature of the target cable is reduced along with the time under the specified laying state, and due to the influence of various other factors (such as environmental factors, current factors and the like), the data generated in the temperature rise stage are temperature rise change data and the data generated in the temperature drop stage are temperature drop change data.
In this embodiment, the implementation process and the data acquisition process of the cable in different laying modes are not limited, and devices capable of implementing different laying states can be selected according to actual conditions to perform temperature change simulation. In order to simplify the process of acquiring the temperature rise and temperature drop change data, preferably, the process of determining the standard data of the temperature rise and temperature drop change in different laying modes according to the reference current-carrying capacity may specifically include the following steps:
1. determining cable models of a target cable in different laying modes;
specifically, the cable models of the cables in different laying modes may be obtained through simulation software (e.g., Comsol multiprophy or Matlab, etc.) or a hot-circuit mathematical model, which is not limited in this embodiment and may refer to related technologies.
2. And inputting the reference current-carrying capacity into a cable model to obtain a temperature rise curve and a temperature drop curve of the target cable under different laying modes, taking the temperature rise curve as temperature rise change data in the temperature change data, and taking the temperature drop curve as temperature drop change standard data in the temperature change data.
Compared with other simulation processes, the process of simulation through the cable model is simpler in implementation process and high in simulation efficiency, the implementation process is only described as an example in the embodiment, and other implementation processes are not described again, and reference can be made to the description in the embodiment.
And step s130, performing thermal cycle test on the cable insulation of the target cable according to the temperature change rule corresponding to each specified laying mode.
The temperature change rule corresponding to the specified laying mode is matched with the temperature change data corresponding to the specified laying mode;
the thermal cycle test process mainly includes testing the performance change of the cable insulation by performing temperature rise and temperature drop on the cable insulation, and because the temperature rise and temperature drop processes of the cable are different under different laying modes, the thermal cycle test on the cable insulation needs to correspond to the temperature change modes under the laying modes, namely the temperature change rule of the cable insulation is matched with the temperature change data corresponding to the specified laying mode, and the temperature change data corresponding to the laying mode in the step s120 is fitted as much as possible.
In this embodiment, the device for performing the thermal cycle test is not limited, and it is sufficient to realize the temperature rise and temperature drop simulation, and specifically, a programmable temperature control aging box can be used to perform the simulated thermal cycle test on each grouped cable sample according to the temperature rise and temperature drop curves in the corresponding laying mode, the programmable temperature control aging box has the functions of adjusting the temperature rise and temperature drop rate, and a curve of the temperature in the aging box changing with time is obtained through a temperature sensor, specifically, the process of performing the thermal cycle test on the cable insulation of the target cable according to the temperature change rule corresponding to each specified laying mode specifically includes: and calling a programmable temperature control aging box to carry out temperature rise and temperature drop heat circulation tests on each cable insulation group according to a preset temperature rise and drop rate regulating mechanism. Of course, other devices may be called to perform the thermal cycle test, and reference may be made to related technologies, which are not described herein.
The number of times of the thermal cycle test can be set according to the test requirement, for example, 80 continuous thermal cycle tests can be set according to the performance analysis of long time span, and data analysis is carried out according to the results of the 80 tests; when only short-term performance test is required, only 1 thermal cycle test or the like may be provided, which is not limited herein.
In order to avoid waste, generally, only the cable insulation slice may be tested, and then the process of performing the thermal cycle test on the cable insulation of the target cable according to the temperature change rule corresponding to each specified laying mode may specifically be: slicing and sampling the cable insulation with the target specification; and carrying out thermal cycle test on the cable insulation slices according to the temperature change rule corresponding to each specified laying mode. And step s140, performing insulation performance analysis on the cable insulation subjected to the thermal cycle test to obtain test insulation performance data.
Various properties of the cable insulation in the thermal cycle test can be changed to different degrees, the cable insulation subjected to the thermal cycle test is subjected to insulation performance analysis, the insulation performance analysis specifically includes an analysis item which is not limited in this embodiment, and various insulation performances which may affect the current-carrying capacity can be used as an analysis item, for example, one or more of physicochemical analysis, electrical analysis and mechanical performance analysis can be included. In order to improve the comprehensiveness of the analysis, the performance analysis can be simultaneously carried out from three aspects of physics, chemistry, electricity and machinery. Specifically, the physical and chemical analysis can be carried out, and comprises microstructure, aggregation state structure analysis and the like, the electrical analysis can comprise four parameter analysis of dielectric constant, dielectric loss, conductivity and breakdown field strength of the dielectric and the like, and the mechanical property analysis can comprise mechanical external characteristic analysis such as tensile strength analysis and the like. In this embodiment, only the above analysis is described as an example, and other performance analysis items may be configured based on the requirement of other insulation performance, which is not described in detail in this embodiment.
And s150, analyzing the cable current-carrying capacity fluctuation conditions in different laying modes according to the tested insulation performance data and the original insulation performance data to generate cable current-carrying capacity fluctuation data.
The original insulation performance data is insulation performance data of original cable insulation without thermal cycle test, the test insulation performance data obtained through the thermal cycle test is compared with the original insulation performance data to generate cable current-carrying capacity fluctuation data, and the cable current-carrying capacity fluctuation data show the influence of temperature change on the insulation performance of the cable insulation.
And step s170, adjusting the current-carrying capacity of the target cable according to the cable current-carrying capacity fluctuation data and preset adjustment rules.
At a reference ampacity IBThe adjusting process may be adjusted based on the size of the insulation performance variation, and specifically, the adjusting process of the current-carrying capacity of the target cable according to the cable current-carrying capacity fluctuation data and the preset adjustment rule may specifically include the following steps:
1. acquiring the insulation performance variable quantity according to the cable current-carrying capacity fluctuation data;
2. judging whether the insulation performance variation reaches a preset variation threshold value;
3. when the current-carrying capacity reaches the standard value, the current-carrying capacity is adjusted down on the basis of the standard current-carrying capacity;
4. and when the current-carrying capacity does not reach the standard current-carrying capacity, the current-carrying capacity is adjusted up on the basis of the standard current-carrying capacity.
Comparing the insulation performance parameters of each group with the performance of unprocessed test samples to obtain the standard load of cables with the same specification based on different laying modesFlow rate IBThe current-carrying capacity adjustment scheme is that the performance of the sample after thermal cycle treatment becomes good or basically unchanged, and the reference current-carrying capacity I can be adjusted upBThe performance is greatly deteriorated, and the reference current-carrying capacity I should be adjusted downwardB。
In addition, the adjustment may be performed when the fluctuation amount of the cable carrying capacity fluctuation data is greater than the fluctuation threshold, which is not described in detail in this embodiment, and reference may be made to the above adjustment manner.
Based on the technical scheme, the method for adjusting the current-carrying capacity of the cable provided by the embodiment intuitively researches the influence of temperature change caused by different laying modes on the performance of the insulating material from the perspective of the insulating nature of the XLPE cable, namely, the quality of the performance of the material is determined by comparing the change of the internal aggregation state structure of the material caused by the steepness of different temperature rise and drop curves for a long time, the heat resistance of the crosslinked polyethylene material is considered, meanwhile, the influence of the internal temperature rise and drop processes of the cable on the insulation, the change of the internal aggregation state structure caused by the difference of the insulation before and after aging and the like are also considered, the fluctuation data of the current-carrying capacity of the cable is determined through comprehensive analysis, and the optimal current-carrying capacity adjustment can be realized on the premise of ensuring the better performance of the.
Example two:
in order to deepen understanding of the method for adjusting the current-carrying capacity of the cable provided by the invention, the embodiment takes a specific implementation process of simulating an XLPE power cable with a known specification in different laying modes, performing thermal cycle treatment on a cable sample, performing an analysis experiment on the insulation performance of the cable, and evaluating the current-carrying capacity of the cable with different aging degrees in different laying modes as an example.
A target cable, namely a test object is a spare cable, and a cable slice sample with the thickness of 0.6mm is obtained by sampling the cable slice; the study was conducted in three common ways: direct-buried laying, pipeline laying and tunnel laying; and the current-carrying capacity of the air laying mode is taken as a reference current-carrying capacity and is set as IB. The flow of this embodiment is schematically shown in fig. 2, and specifically includes the following steps:
1. a model establishing stage: the Commol Multiphysics 5.3a software is selected, because the actual length of the cable can be approximate to infinity relative to the radius of the section, a two-dimensional cable model is constructed according to the section structure parameters of the tested cable, and various physical parameters are correspondingly input according to actual materials. And abstracting according to three different laying conditions, respectively establishing corresponding two-dimensional geometric models, and inputting corresponding structure and material parameters. Then adding physical fields such as a magnetic field, a solid heat transfer field, a turbulent flow field and the like according to actual needs, coupling the physical fields, and inputting the physical fields into a corresponding control equation. (because finite element method is used for solving, grid division is needed, probes are placed for monitoring experimental data, and other solving methods are not described in detail herein.)
2. A simulation experiment stage: in order to amplify the temperature rise curve difference in the temperature rise stages of different laying modes and verify the reliability of the cable under the emergency overload condition, 1.2I is adoptedBThe current values are respectively substituted into the cable conductors with the same specification in the three different laying modes, and the operation is simulated for a period of time to obtain three different temperature rise curves; when the conductor temperature reaches 90 ℃ quickly, the time of the point is recorded, and the conductor current is changed to IBThe conductor temperature is kept constant near 90 ℃ and the conductor is operated for 2 hours at constant temperature so as to simulate the real steady-state operation condition; after the constant temperature operation is carried out for 2 hours, the conductor current is removed, the simulation operation is carried out for a period of time again, the cable is naturally cooled down and is placed at room temperature, and therefore a complete temperature-time curve graph of direct burial laying, pipeline laying and tunnel laying is obtained.
3. And (3) cable sample treatment stage: and reproducing the temperature-time curve graphs of direct-buried laying, pipeline laying and tunnel laying obtained by simulation through a specially-made aging constant temperature box, and respectively carrying out the three temperature circulation treatments on the spare cable samples for 80 times so as to enlarge the difference between the samples due to different temperature rise and temperature drop rates.
4. Cable insulation performance analysis experiment stage: and analyzing the related physical and chemical properties, electrical properties and mechanical properties of the samples before and after treatment.
Wherein, the physical and chemical property analysis test is as follows: DS (direct sequence)C experiment and flurier infrared spectrum experiment. Electrical analysis: space charge, breakdown voltage, conductance current, etc. The mechanical property analysis experiment is as follows: and (4) tensile test. By comparing the performances of the cable samples with the same load strength and different laying modes and different operation years, the standard current-carrying capacity I can be obtainedBComparing the performances of the cables with the known specifications under different laying modes to obtain a current-carrying capacity adjusting strategy under corresponding conditions, namely the cables with the material performance kept in a better state after long-term temperature circulation can have a reference current-carrying capacity IBAnd on the basis, adjusting upwards, and otherwise, adjusting downwards.
The cable current-carrying capacity adjustment mode that this embodiment provided sets out from the heat resistance's of crosslinked polyethylene material angle of self, considers the influence of the inside intensification of cable and cooling process to insulating, assesses the cable current-carrying capacity change through actual experiment to obtain the cable condition that accords with reality more, more accurate assessment result provides new thinking for formulating the same specification XLPE power cable current-carrying capacity under the different mode of laying.
Example three:
referring to fig. 3, fig. 3 is a block diagram of a cable current-carrying capacity adjustment apparatus provided in this embodiment; the apparatus may include: the device comprises a reference current capacity obtaining unit 210, a change standard determining unit 220, a thermal cycle testing unit 230, an insulation performance analyzing unit 240, a flow fluctuation analyzing unit 250 and a current capacity adjusting unit 260. The cable ampacity adjusting device provided by the embodiment can be contrasted with the cable ampacity adjusting method.
The reference ampacity obtaining unit 210 is mainly configured to obtain an ampacity of a target cable, and use the obtained ampacity as a reference ampacity;
the change standard determination unit 220 is mainly used for determining temperature change data under different laying modes according to the reference current-carrying capacity;
the thermal cycle test unit 230 is mainly used for performing a thermal cycle test on the cable insulation of the target cable according to the temperature change rule corresponding to each specified laying mode; the temperature change rule corresponding to the specified laying mode is matched with the temperature change data corresponding to the specified laying mode;
the insulation performance analysis unit 240 is mainly used for analyzing the insulation performance of the cable subjected to the thermal cycle test to obtain test insulation performance data;
the flow fluctuation analysis unit 240 is mainly used for analyzing the cable current-carrying capacity fluctuation conditions in different laying modes according to the tested insulation performance data and the original insulation performance data to generate cable current-carrying capacity fluctuation data; the original insulation performance data is insulation performance data of original cable insulation without thermal cycle test;
the current-carrying capacity adjusting unit 250 is mainly configured to adjust the current-carrying capacity of the target cable according to the cable current-carrying capacity fluctuation data and a preset adjusting rule.
Optionally, the insulation performance analysis unit may specifically include: a physical and chemical analysis subunit, an electrical analysis subunit and a mechanical performance analysis subunit;
the physicochemical analysis subunit specifically includes: a microstructure analysis subunit and an aggregation state structure analysis subunit;
the electrical analysis subunit may specifically include: a dielectric constant analysis subunit, a dielectric loss analysis subunit, a conductivity analysis subunit and a breakdown field strength analysis subunit of the dielectric;
the mechanical property analysis subunit specifically includes: and a mechanical external characteristic analysis subunit.
The mechanical external characteristic analysis subunit can be specifically used for performing tensile strength analysis.
Optionally, the thermal cycling test unit may specifically include:
the model determining subunit is used for determining cable models of the target cable in different laying modes;
and the model calling subunit is used for inputting the reference current-carrying capacity into the cable model to obtain a temperature rise curve and a temperature drop curve of the target cable in different laying modes, taking the temperature rise curve as temperature rise change data in the temperature change data, and taking the temperature drop curve as temperature drop change standard data in the temperature change data.
Optionally, the thermal cycling test unit may specifically be a burn-in box test unit, configured to:
and calling a programmable temperature control aging box to carry out temperature rise and temperature drop heat circulation tests on each cable insulation group according to a preset temperature rise and drop rate regulating mechanism.
Optionally, the current-carrying capacity adjusting unit may specifically include:
the variable acquiring subunit is used for acquiring the insulation performance variable according to the cable current-carrying capacity fluctuation data;
the variation judging subunit is used for judging whether the insulation performance variation reaches a preset variation threshold;
the lower regulating subunit is used for regulating the current-carrying capacity on the basis of the reference current-carrying capacity when the insulation performance variation reaches a preset variation threshold;
and the up-regulation subunit is used for up-regulating the current-carrying capacity on the basis of the reference current-carrying capacity when the insulation performance variation does not reach the preset variation threshold.
Optionally, the reference current-carrying capacity obtaining unit may specifically be a first obtaining unit, configured to: and acquiring an input current effective value corresponding to the target cable when the conductor reaches 90 ℃, and taking the input current effective value as a reference current-carrying capacity.
Optionally, the reference current-carrying capacity obtaining unit may specifically be a second obtaining unit, configured to: and acquiring the carrying capacity of the target cable in the air domain.
The cable ampacity adjusting device that this embodiment provided is to cable ampacity adjustment accuracy height.
Example four:
referring to fig. 4, fig. 4 is a block diagram of a structure of a cable current-carrying capacity adjusting apparatus provided in this embodiment; the apparatus may include: a memory 300 and a processor 310. The cable ampacity adjusting device can refer to the introduction of the cable ampacity adjusting method.
The memory 300 is mainly used for storing programs;
the processor 310 is mainly used for implementing the steps of the cable ampacity adjustment method when executing the program.
Referring to fig. 5, a schematic structural diagram of a cable ampacity adjustment device provided in this embodiment is shown, where the adjustment device may generate a relatively large difference due to different configurations or performances, and may include one or more processors (CPUs) 322 (e.g., one or more processors) and a memory 332, and one or more storage media 330 (e.g., one or more mass storage devices) storing an application 342 or data 344. Memory 332 and storage media 330 may be, among other things, transient storage or persistent storage. The program stored on the storage medium 330 may include one or more modules (not shown), each of which may include a series of instructions operating on a data processing device. Still further, the central processor 322 may be configured to communicate with the storage medium 330 to execute a series of instruction operations in the storage medium 330 on the adjustment device 301.
The scaling device 301 may also include one or more power supplies 326, one or more wired or wireless network interfaces 350, one or more input-output interfaces 358, and/or one or more operating systems 341, such as Windows Server, Mac OS XTM, UnixTM, LinuxTM, FreeBSDTM, and so forth.
The steps in the cable ampacity adjusting method described above may be implemented by the structure of the cable ampacity adjusting apparatus provided in this embodiment.
Example five:
the embodiment discloses a readable storage medium, where a program is stored on the readable storage medium, and the program is executed by a processor to implement a step of a cable ampacity adjustment method, where the cable ampacity adjustment method may refer to the embodiment corresponding to fig. 1, and details are not described here again.
The readable storage medium may be a usb disk, a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk or an optical disk, and various other readable storage media capable of storing program codes.
The embodiments are described in a progressive manner in the specification, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other. The device disclosed by the embodiment corresponds to the method disclosed by the embodiment, so that the description is simple, and the relevant points can be referred to the method part for description.
Those of skill would further appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, computer software, or combinations of both, and that the various illustrative components and steps have been described above generally in terms of their functionality in order to clearly illustrate this interchangeability of hardware and software. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the implementation. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.
The steps of a method or algorithm described in connection with the embodiments disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module may reside in Random Access Memory (RAM), memory, Read Only Memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art.
The method, the device, the equipment and the readable storage medium for adjusting the current-carrying capacity of the cable provided by the invention are described in detail above. The principles and embodiments of the present invention are explained herein using specific examples, which are presented only to assist in understanding the method and its core concepts. It should be noted that, for those skilled in the art, it is possible to make various improvements and modifications to the present invention without departing from the principle of the present invention, and those improvements and modifications also fall within the scope of the claims of the present invention.
Claims (10)
1. A method for adjusting the current-carrying capacity of a cable is characterized by comprising the following steps:
acquiring the current-carrying capacity of a target cable, and taking the acquired current-carrying capacity as a reference current-carrying capacity;
determining temperature change data of the target cable in a specified laying mode according to the reference current-carrying capacity; wherein the temperature change data comprises a temperature rise curve and a temperature drop curve;
carrying out thermal cycle test on the cable insulation of the target cable according to the temperature change rule corresponding to each specified laying mode; the temperature change rule corresponding to the specified laying mode is matched with the temperature change data corresponding to the specified laying mode;
analyzing the insulation performance of the cable insulation subjected to the thermal cycle test to obtain test insulation performance data;
analyzing the current-carrying capacity fluctuation conditions of the cable in different laying modes according to the test insulation performance data and the original insulation performance data to generate cable current-carrying capacity fluctuation data; wherein the original insulation performance data is the insulation performance data of the original cable insulation which is not subjected to the thermal cycle test;
and adjusting the current-carrying capacity of the target cable according to the cable current-carrying capacity fluctuation data and preset adjustment rules.
2. The method for adjusting the ampacity of a cable according to claim 1, wherein the analyzing the insulation performance of the cable insulation subjected to the thermal cycle test comprises:
performing physical and chemical analysis, electrical analysis and mechanical performance analysis on the cable insulation subjected to the thermal cycle test;
wherein the physicochemical analysis comprises: analyzing microstructure and aggregation state structure;
the electrical analysis comprises: analyzing four parameters of dielectric constant, dielectric loss, conductivity and breakdown field intensity of the dielectric medium;
the mechanical property analysis comprises: and (5) analyzing the mechanical external characteristics.
3. The method for adjusting the current-carrying capacity of the cable according to claim 1, wherein determining the temperature change data of the target cable in the specified laying mode according to the reference current-carrying capacity comprises:
determining cable models of the target cable in different laying modes;
and inputting the reference current-carrying capacity into the cable model to obtain a temperature rise curve and a temperature drop curve of the target cable under different laying modes, taking the temperature rise curve as temperature rise change data in the temperature change data, and taking the temperature drop curve as temperature drop change standard data in the temperature change data.
4. The method for adjusting the current-carrying capacity of the cable according to claim 1, wherein performing a thermal cycle test on the cable insulation of the target cable according to the temperature change rule corresponding to each of the specified laying modes comprises:
and calling a programmable temperature control aging box to carry out temperature rise and temperature drop heat circulation tests on each cable insulation group according to a preset temperature rise and drop rate regulating mechanism.
5. The method for adjusting the current-carrying capacity of the cable according to claim 1, wherein the adjusting the current-carrying capacity of the target cable according to the cable current-carrying capacity fluctuation data and the preset adjustment rule comprises:
acquiring insulation performance variable quantity according to the cable current-carrying capacity fluctuation data;
judging whether the insulation performance variation reaches a preset variation threshold value;
when the current-carrying capacity reaches the standard current-carrying capacity, the current-carrying capacity is adjusted downwards on the basis of the standard current-carrying capacity;
and when the current-carrying capacity does not reach the standard current-carrying capacity, adjusting the current-carrying capacity on the basis of the standard current-carrying capacity.
6. The method for adjusting the current-carrying capacity of the cable according to claim 1, wherein the obtaining the current-carrying capacity of the target cable comprises:
and acquiring an input current effective value corresponding to the target cable when the conductor reaches 90 ℃, and taking the input current effective value as the reference current-carrying capacity.
7. The method for adjusting the current-carrying capacity of the cable according to claim 1, wherein the obtaining the current-carrying capacity of the target cable comprises:
and acquiring the current carrying capacity of the target cable in the air domain.
8. A cable ampacity adjustment device, comprising:
the reference current-carrying capacity obtaining unit is used for obtaining the current-carrying capacity of the target cable and taking the obtained current-carrying capacity as the reference current-carrying capacity;
the change standard determining unit is used for determining temperature change data under different specified laying modes according to the reference current-carrying capacity; wherein the temperature change data comprises a temperature rise curve and a temperature drop curve;
the thermal cycle test unit is used for performing thermal cycle test on the cable insulation of the target cable according to the temperature change rule corresponding to each specified laying mode; the temperature change rule corresponding to the specified laying mode is matched with the temperature change data corresponding to the specified laying mode;
the insulation performance analysis unit is used for carrying out insulation performance analysis on the cable insulation subjected to the thermal cycle test to obtain test insulation performance data;
the flow fluctuation analysis unit is used for analyzing the cable current-carrying capacity fluctuation conditions in different laying modes according to the test insulation performance data and the original insulation performance data to generate cable current-carrying capacity fluctuation data; wherein the original insulation performance data is the insulation performance data of the original cable insulation which is not subjected to the thermal cycle test;
and the current-carrying capacity adjusting unit is used for adjusting the current-carrying capacity of the target cable according to the cable current-carrying capacity fluctuation data and preset adjusting rules.
9. A cable ampacity adjustment device, comprising:
a memory for storing a program;
a processor for implementing the steps of the method for adjusting the current-carrying capacity of a cable according to any one of claims 1 to 7 when executing the program.
10. A readable storage medium, characterized in that the readable storage medium stores a program, and the program is executed by a processor to implement the steps of the cable ampacity adjustment method according to any one of claims 1 to 7.
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| CN113628264A (en) * | 2021-07-28 | 2021-11-09 | 武汉三江中电科技有限责任公司 | Image registration algorithm for nondestructive testing of power transmission and transformation equipment state |
| CN115267348A (en) * | 2022-07-11 | 2022-11-01 | 江苏亨通高压海缆有限公司 | Submarine cable armored loss factor test system and test calculation method thereof |
| CN115015683B (en) * | 2022-08-09 | 2022-11-04 | 深圳永贵技术有限公司 | Cable production performance test method, device, equipment and storage medium |
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| CN109490664A (en) * | 2018-10-30 | 2019-03-19 | 国网江苏省电力有限公司南通供电分公司 | A kind of practical carrying current calculation method of underground laying distribution line cable |
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| CN103048568B (en) * | 2012-12-21 | 2015-10-21 | 广东电网公司佛山供电局 | Three-core cable laid in cable duct current-carrying method for determination of amount and certainty annuity |
| CN203191472U (en) * | 2013-04-02 | 2013-09-11 | 国家电网公司 | Cable current-carrying capacity analysis system based on linear temperature sensing technology |
| CN105205229B (en) * | 2015-09-02 | 2018-10-16 | 江苏省电力公司南京供电公司 | A kind of current-carrying capability dynamic assessment method that high voltage single-core cable is met an urgent need under load |
| CN106294963A (en) * | 2016-08-04 | 2017-01-04 | 国网上海市电力公司 | Direct-buried cable carrying current calculation method |
| CN107169216A (en) * | 2017-05-24 | 2017-09-15 | 上海电力设计院有限公司 | Current-carrying capacity of cable computational methods based on finite element |
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