CN113589065A - Method and device for testing current carrying capacity of directly-buried cable - Google Patents
Method and device for testing current carrying capacity of directly-buried cable Download PDFInfo
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- 238000012360 testing method Methods 0.000 title claims abstract description 103
- 238000000034 method Methods 0.000 title claims abstract description 32
- 230000007613 environmental effect Effects 0.000 claims abstract description 48
- 239000002689 soil Substances 0.000 claims description 62
- 239000000463 material Substances 0.000 claims description 22
- 238000012545 processing Methods 0.000 claims description 11
- 239000002184 metal Substances 0.000 claims description 8
- 238000001514 detection method Methods 0.000 claims description 7
- 238000009434 installation Methods 0.000 claims description 5
- 238000009933 burial Methods 0.000 claims description 3
- 238000010998 test method Methods 0.000 claims 2
- 239000000126 substance Substances 0.000 claims 1
- 238000011160 research Methods 0.000 abstract description 4
- 230000002159 abnormal effect Effects 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- 238000012986 modification Methods 0.000 description 3
- 230000004048 modification Effects 0.000 description 3
- 238000009529 body temperature measurement Methods 0.000 description 2
- 239000004020 conductor Substances 0.000 description 2
- 238000009412 basement excavation Methods 0.000 description 1
- 230000033228 biological regulation Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
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- G—PHYSICS
- G01—MEASURING; TESTING
- 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
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- G—PHYSICS
- G01—MEASURING; TESTING
- 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
- G01R31/003—Environmental or reliability tests
Abstract
The invention provides a method and a device for testing the current carrying capacity of a directly-buried cable, wherein the method comprises the following steps: a selecting step, namely determining a test site, wherein the environmental parameters of the test site are within a preset range; a laying step, namely laying the first sample and the second sample on a test field, wherein the first sample and the second sample have different structures and/or parameters and/or different laying modes; and a testing step, namely applying current to the first sample and the second sample, detecting the current value and the temperature value of the first sample and the second sample after a preset time interval, and comparing the current carrying capacity of the first sample and the second sample according to the detected current value and temperature value. According to the invention, the environmental factors of the first sample and the second sample during laying are controlled, the structure, the parameter difference and the laying mode of the first sample and the second sample are taken as research factors, the current carrying capacity of the first sample and the current carrying capacity of the second sample are accurately compared, and the influence of the difference of the first sample and the second sample on the current carrying capacity is accurately mastered.
Description
Technical Field
The invention relates to the technical field of electrical tests, in particular to a method and a device for testing current-carrying capacity of a directly-buried cable.
Background
Direct-buried laying is a relatively common laying mode in a power cable line, and during laying, factors such as soil components, soil temperature and soil thermal resistance coefficient in environmental parameters, earth surface wind speed and sunlight conditions, a backfill mode of a laying area and the like can influence the local current-carrying capacity of the cable line, so that the whole current-carrying capacity of the cable line is limited. Moreover, the difference in the structure of different cables can also affect the operation loss and the heat dissipation capability thereof. However, under the influence of various factors, the influence of the cable structure difference on the current carrying capacity of the cable line cannot be accurately grasped.
Disclosure of Invention
In view of the above, the invention provides a method for testing the current-carrying capacity of a directly-buried cable, and aims to solve the problem that the current-carrying capacity of a cable line cannot be influenced by the difference of cable structures in the prior art. The invention also provides a device for testing the current carrying capacity of the directly-buried laying cable.
In one aspect, the invention provides a method for testing current carrying capacity of a directly-buried cable, which comprises the following steps: a selecting step, namely determining a test site, wherein the environmental parameters of the test site are within a preset range; a laying step, namely laying a first sample and a second sample on a test field, wherein the first sample and the second sample have different structures and/or parameters and/or different laying modes; and a testing step, namely applying current to the first sample and the second sample, detecting the current value and the temperature value of the first sample and the second sample after a preset time interval, and comparing the current carrying capacity of the first sample and the second sample according to the detected current value and temperature value of the first sample and the second sample.
Further, in the method for testing the current carrying capacity of the directly-buried cable, the selecting step further includes: a first determination substep of determining the size of the test site based on the specifications of the first sample and the second sample; selecting a continuous soil area with similar soil components, flat surface and no underground heat source or cable line facility as a to-be-selected area; a measuring substep, measuring environmental parameters at different positions in the region to be selected; if the standard deviation of the environmental parameters at each position of the area to be selected is within a preset range, determining the area to be selected as a test field; and if the standard deviation of the environmental parameters at the positions of the to-be-selected area exceeds a preset range, repeating the second determining substep and the measuring substep until the standard deviation of the environmental parameters at the positions of the to-be-selected area is within the preset range.
Further, in the method for testing current-carrying capacity of a buried cable, the environmental parameter includes at least one of the following: soil thermal resistivity, soil temperature and wind speed.
Further, in the method for testing the current carrying capacity of the direct-buried cable, in the first determining substep, the greater value of the length of the first sample and the length of the second sample is determined as the length of the two sample areas; determining the larger value of the laying width required by the first sample and the laying width of the second sample as the width of the two sample areas; and determining the size of the test site according to the length and the width of the two sample areas and the requirement of the reserved site of the test work.
Further, in the method for testing current carrying capacity of a directly-buried cable, the laying step further includes: a mounting substep of mounting a temperature measuring device on each of the first sample and the second sample; a detection substep of detecting the temperature of the same structure of the first sample and the second sample; if the temperature deviation of the same structure of the first sample and the second sample exceeds a preset control range, repeating the installation substep and the detection substep until the temperature deviation of the same structure of the first sample and the second sample is within the preset control range; and in the sub-step of direct burial laying, two grooves are dug in a test field, the first sample and the second sample are respectively placed into the two dug grooves, and the two grooves are backfilled.
Further, in the method for testing the current-carrying capacity of the direct-buried cable, in the laying step, the first sample and the second sample both include: a cable body; the parameters of the first and second samples being different include: the models of the cable bodies are different; the structural differences of the first and second samples include: at least one of the samples is provided with an attachment structure, the attachment structure being of a different structure when the sample is provided with the attachment structure; wherein the auxiliary structure comprises at least one of the following: the cable joint, the conduit and the cable body are provided with armor and metal shielding layer connecting sections; the first sample and the second sample are laid differently, and the laying method comprises the following steps: the backfill materials are different, the backfill material distribution modes are different, and the covers of the grooves after backfill are different.
Further, in the method for testing the current carrying capacity of the directly-buried cabling, in the sub-step of directly-buried cabling, the temperature of the same structure of the first sample and the second sample is detected, if the temperature deviation of the same structure of the first sample and the second sample exceeds a preset control range, faults are eliminated or two grooves are dug again in a test site, the first sample and the second sample are respectively placed into the two dug grooves, and then the two grooves are backfilled.
Further, in the method for testing the current carrying capacity of the buried cable, in the testing step, the first end of the first sample and the first end of the second sample are connected, the current generating device is installed between the second end of the first sample and the second end of the second sample, current is applied to the first sample and the second sample through the current generating device, and the current values of the first sample and the second sample are detected through the current generating device.
According to the invention, the environmental parameters of the test field are controlled within a preset range, the first sample and the second sample are laid on the test field, and the first sample and the second sample have different structures and/or parameters, so that the environmental factors of the first sample and the second sample during laying are controlled, the structures, the parameters and the laying modes of the first sample and the second sample are used as research factors, the current carrying capacities of the first sample and the second sample are compared according to the current values and the temperature values of the first sample and the second sample, the current carrying capacities of the first sample and the second sample can be accurately compared, the influence of the difference of the first sample and the second sample on the current carrying capacity can be accurately mastered, and the problem that the influence of the difference of the cable structure on the current carrying capacity of a cable line cannot be accurately mastered in the prior art is solved.
On the other hand, the invention also provides a device for testing the current-carrying capacity of the directly-buried cable, which comprises: the device comprises a current generating device, a data processing device and two temperature measuring devices; the current generating device is arranged between the second end of the first sample and the second end of the second sample, the first end of the first sample is connected with the first end of the second sample, the first sample and the second sample are directly buried and arranged in a test field, the environmental parameters of the test field are within a preset range, the structures and/or parameters of the first sample and the second sample are different, and/or the laying modes of the first sample and the second sample are different; the two temperature measuring devices are respectively arranged at the corresponding structural positions of the first sample and the second sample, and each temperature measuring device is used for measuring the temperature of the corresponding sample; the data processing device is electrically connected with the current generating device and the two sample temperature measuring devices and used for controlling the current generating device to apply current to the first sample and the second sample, controlling the current generating device to detect the current values of the first sample and the second sample after a preset time interval, controlling the two temperature measuring devices to measure the temperature values of the first sample and the second sample, and comparing the current carrying capacity of the first sample and the second sample according to the detected current values and temperature values of the first sample and the second sample.
Further, in the buried cable current-carrying capacity testing apparatus, the environmental parameter includes at least one of the following: soil thermal resistivity, soil temperature and wind speed; the first sample and the second sample each comprise: a cable body; the parameters of the first and second samples being different include: the models of the cable bodies are different; the structural differences of the first and second samples include: at least one of the samples is provided with an attachment structure, the attachment structure being of a different structure when the sample is provided with the attachment structure; wherein the auxiliary structure comprises at least one of the following: the cable joint, the conduit and the cable body are provided with armor and metal shielding layer connecting sections; the first sample and the second sample are laid differently, and the laying method comprises the following steps: the backfill materials are different, the backfill material distribution modes are different, and the covers of the grooves after backfilling are different; two grooves are formed in the test field, the first sample and the second sample are laid in the two grooves in a one-to-one correspondence mode, and each groove can be used for backfilling after the samples are laid.
The method for testing the current-carrying capacity of the directly-buried cable has the advantages, so the device for testing the current-carrying capacity of the directly-buried cable also has corresponding technical effects.
Drawings
Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the invention. Also, like reference numerals are used to refer to like parts throughout the drawings. In the drawings:
fig. 1 is a flowchart of a method for testing current-carrying capacity of a direct-buried cable according to an embodiment of the present invention;
fig. 2 is a schematic structural diagram of a direct-buried cable current-carrying capacity testing apparatus according to an embodiment of the present invention.
Detailed Description
Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art. It should be noted that the embodiments and features of the embodiments may be combined with each other without conflict. The present invention will be described in detail below with reference to the embodiments with reference to the attached drawings.
The method comprises the following steps:
referring to fig. 1, fig. 1 is a flowchart of a method for testing current carrying capacity of a direct-buried cable according to an embodiment of the present invention. As shown in the figure, the method for testing the current carrying capacity of the direct-buried cable comprises the following steps:
and selecting step S1, and determining a test site, wherein the environmental parameters of the test site are in a preset range.
Specifically, the environmental parameter includes at least one of: soil thermal resistivity, soil temperature and wind speed. Selecting a to-be-selected area in a test field, detecting soil thermal resistance coefficients, soil temperature and wind speed of a plurality of different positions of the to-be-selected area through an environmental parameter measuring device to judge whether the soil thermal resistance coefficients, the soil temperature and the wind speed standard deviation of each position of the to-be-selected area are controlled within a preset range, determining the to-be-selected area as the test field if the soil thermal resistance coefficients, the soil temperature and the wind speed standard deviation are controlled within the preset range, and reselecting the test field if the soil thermal resistance coefficients, the soil temperature and the wind speed standard deviation are not controlled within the preset range.
The selecting step S1 further includes:
the first determining substep S11 determines the size of the test site based on the specifications of the first sample and the second sample.
Specifically, the greater of the length of the first sample and the length of the second sample is determined as the length of the two sample regions; determining the larger value of the laying width required by the first sample and the laying width of the second sample as the width of the two sample areas; and determining the size of the test site according to the length and the width of the two sample areas and the requirement of the reserved site of the test work.
More specifically, referring to fig. 2, the area where the first sample 4 is laid is a first sample area, the area where the second sample 5 is laid is a second sample area, and the length and the width of the first sample area and the second sample area should be the same, so the first sample area and the second sample area may be collectively referred to as a sample area.
Determining a length of the first sample region based on a length of the first sample, determining a length of the second sample region based on a length of the second sample, and determining a greater of the length of the first sample region and the length of the second sample region as the length of the sample region.
Determining the width of a first sample area according to the width of the laying ground required by the first sample, determining the width of a second sample area according to the width of the laying ground required by the second sample, and determining the larger value of the width of the first sample area and the width of the second sample area as the width of the sample area.
And determining the size of the test site according to the length and the width of the sample area and the requirement of the reserved site of the test work.
In the second determining substep S12, a continuous soil area with similar soil composition, smooth surface and no underground heat source or cable line facility is selected as a candidate area.
A measurement sub-step S13 of measuring the environmental parameter at different locations in the region to be selected.
If the standard deviation of the environmental parameters at each position of the area to be selected is within a preset range, determining the area to be selected as a test field; and if the standard deviation of the environmental parameters at the positions of the candidate area exceeds the preset range, repeating the second determining substep S12 and the measuring substep S13 until the standard deviation of the environmental parameters at the positions of the candidate area is within the preset range.
Specifically, a plurality of typical positions are selected in the candidate area, the structures of the typical positions in the candidate area are the same, and the environmental parameters at the typical positions are measured in the same time period. Wherein the environmental parameter comprises at least one of: and calculating the standard deviation according to the measured values of the environmental parameters corresponding to a plurality of positions of the area to be selected, and judging whether the standard deviation corresponding to each environmental parameter is within a preset range. And if the standard deviation of the environmental parameters at each position of the area to be selected does not exceed the corresponding preset range, determining the area to be selected as a test field. And if one standard deviation of the standard deviations of the environmental parameters at the positions of the to-be-selected area exceeds the corresponding preset range, repeating the second determining substep S12 and the measuring substep S13 until the standard deviations of the environmental parameters at the positions of the to-be-selected area do not exceed the corresponding preset range, and determining the to-be-selected area as the test site.
In specific implementation, for the environmental parameter of the thermal resistivity of the soil, the thermal resistivity of the soil at a plurality of typical positions in the selected area is measured, the standard deviation of the thermal resistivity of the soil is calculated according to the thermal resistivity of the soil at each position, and whether the standard deviation of the thermal resistivity of the soil exceeds a preset range is judged, wherein the preset range is corresponding to the thermal resistivity of the soil.
For the environmental parameter of the soil temperature, measuring the soil temperature at a plurality of typical positions of the area to be selected, calculating the standard deviation of the soil temperature according to the soil temperature at each position, and judging whether the standard deviation of the soil temperature exceeds a preset range, wherein the preset range is corresponding to the soil temperature.
For the environmental parameter of the wind speed, measuring the wind speeds at a plurality of typical positions in the area to be selected, calculating the standard deviation of the wind speed according to the wind speeds at the positions, and judging whether the standard deviation of the wind speed exceeds a preset range, wherein the preset range is corresponding to the wind speed.
The preset range for judging the standard deviation in the soil thermal resistance coefficient, the preset range for judging the standard deviation in the soil temperature and the preset range for judging the standard deviation in the wind speed can be respectively determined according to actual conditions, but when the standard deviation of the soil thermal resistance coefficient, the standard deviation of the soil temperature and the standard deviation of the wind speed do not exceed the corresponding preset ranges, the selected area is determined as a test site. And if one standard deviation of the thermal resistance coefficient of the soil, the standard deviation of the temperature of the soil and the standard deviation of the wind speed exceeds a corresponding preset range, repeating the second determining substep S12 and the measuring substep S13.
The environmental parameter is measured by an environmental parameter measuring device 6, and the environmental parameter measuring device 6 may include: the device comprises a wind speed acquisition device, a soil temperature acquisition device and a soil thermal resistance coefficient acquisition device.
And a step S2 of applying a first sample and a second sample to the test site, wherein the first sample and the second sample have different structures and/or parameters and/or are applied in different ways.
Specifically, first, a first sample and a second sample are prepared, and the first sample and the second sample are respectively laid on two sample areas of a test field in a one-to-one correspondence manner.
The first sample and the second sample each comprise: a cable body. The parameters of the first and second samples being different include: the models of the cable bodies are different; the structural differences of the first and second samples include: at least one of the samples is provided with an attachment structure, the attachment structure being of a different structure when the sample is provided with the attachment structure; wherein the auxiliary structure comprises at least one of the following: the cable joint, the conduit and the cable body are provided with armor and metal shielding layer connecting sections.
More specifically, conductor connection sections were made in each sample at both ends of the cable body. The difference between the first and second samples may be manifested in: the cable bodies are different in model; one of the cable bodies is provided with an auxiliary structure, and the other cable body is not provided with the auxiliary structure; the attachment structures on the two cable bodies are different, etc. The cable body can be provided with a cable connector, can also be provided with a conduit, and can also be provided with an armor and metal shielding layer connecting section.
The first sample and the second sample are laid differently, and the laying method comprises the following steps: the backfill materials are different, the backfill material distribution modes are different, and the covers of the grooves after backfill are different. Specifically, two grooves are formed in a test site, the first sample and the second sample are placed in the two grooves in a one-to-one correspondence mode, then the two grooves are backfilled, the backfilling materials can be different, the distribution mode of the backfilling materials can be different, and the covering of the backfilled grooves can be different. Wherein, backfill material distribution mode can include: the volume, shape, etc. of the backfill material. To avoid the effects of light, a cover may be placed over the backfill material after backfilling.
And a testing step S3, applying current to the first sample and the second sample, detecting the current value and the temperature value of the first sample and the second sample after a preset time interval, and comparing the current carrying capacity of the first sample and the second sample according to the detected current value and temperature value of the first sample and the second sample.
Specifically, referring to fig. 2, a first end of a first sample 4 and a first end of a second sample 5 are connected, a current generating device 1 is installed between a second end of the first sample 4 and a second end of the second sample 5, a current is applied to the first sample 4 and the second sample 5 through the current generating device 1, and a current value of the first sample 4 and the second sample 5 is detected through the current generating device 1. More specifically, the current is applied to the first sample 4 and the second sample 5 by the current generating device 1 according to the test requirements, and the current applied to the first sample 4 and the second sample 5 at each time is the same, but the current applied to two adjacent times may be the same or different.
In specific implementation, the current generating device is a device capable of generating current with adjustable amplitude.
In specific implementation, the preset time may be determined according to actual conditions, and this embodiment does not limit this.
It can be seen that, in this embodiment, the environmental parameters of the test site are controlled within the preset range, the first sample and the second sample are both laid on the test site, and the structures and/or parameters of the first sample and the second sample are different, so as to control the environmental factors when the first sample and the second sample are laid, the structures, parameters and laying modes of the first sample and the second sample are used as research factors, and then the current carrying capacities of the first sample and the second sample are compared according to the current values and temperature values of the first sample and the second sample, so that the current carrying capacities of the first sample and the second sample can be accurately compared, further the influence of the difference between the first sample and the second sample on the current carrying capacity can be accurately grasped, and the problem that the influence of the cable structure difference on the current carrying capacity of a cable line cannot be accurately grasped in the prior art is solved.
In the above embodiment, the laying step S2 further includes:
the installation substep S21 is to install a temperature measuring device on each of the first sample and the second sample.
And a detection substep S22 of detecting the temperature at the same structure of the first sample and the second sample.
If the temperature deviation of the same structure of the first sample and the second sample exceeds the preset control range, the installation substep S21 and the detection substep S22 are repeated until the temperature deviation of the same structure of the first sample and the second sample is within the preset control range.
Specifically, if the deviation of the temperature measurement values at the same structure of the first sample and the second sample exceeds the preset control range or is obviously abnormal, the installation substep S21 and the detection substep S22 are repeated to ensure that the deviation of the temperature at the same structure of the first sample and the second sample is controlled within the preset control range.
And a direct burial laying substep S23, digging two grooves on a test site, respectively placing the first sample and the second sample into the two dug grooves, and backfilling the two grooves.
Specifically, two sample areas are arbitrarily selected at the test site, and soil is excavated according to the length and width of the sample area determined in the first determining substep S11 to form two grooves, which are the two sample areas. The excavated soil naturally piles on the ground surface in the adjacent area. Preferably, an isolation wall is built in each sample area.
Then, the first sample and the second sample are respectively placed into the two dug grooves in a one-to-one correspondence mode, the dug soil or specific media are backfilled into the two grooves according to experiment requirements, and the backfilled soil or the backfilled media are guaranteed to naturally sink to be flush with the ground. Preferably, a cover is placed over the backfilled soil or media after backfilling to block sunlight.
Preferably, the armouring and metallic shielding of the cable are earthed.
Detecting the temperature of the same structure of the first sample and the second sample in the process of placing and backfilling and after backfilling, if the temperature deviation of the same structure of the first sample and the second sample exceeds a preset control range, eliminating faults or digging two grooves in a test field again, placing the first sample and the second sample into the two dug grooves respectively, and backfilling the two grooves. Specifically, the temperature measuring device at the first sample detects the temperature of the first sample, the temperature measuring device at the second sample detects the temperature of the second sample, if the deviation between the temperature of the first sample and the temperature of the second sample exceeds a preset control range or is obviously abnormal, the abnormal reason is checked, the fault is eliminated, and the excavation, the laying and the backfilling are carried out when necessary.
It can be seen that, in this embodiment, the temperatures of the first sample and the second sample are detected before the first sample and the second sample are laid, and after the temperatures of the first sample and the second sample are controlled within the preset control range, the first sample and the second sample are laid, so that the temperatures of the first sample and the second sample when laid can be guaranteed to be consistent, the influence on the comparison result due to inconsistent temperatures when laid is avoided, and the accurate judgment and comparison of the current carrying capacity is further guaranteed.
In specific implementation, referring to fig. 2, the current generating device 1, the two temperature measuring devices 3 and the environmental parameter measuring device 6 are all electrically connected to the data processing device 2, the data processing device 2 controls the current generating device 1 to apply current to the first sample 4 and the second sample 5, after a preset time interval, the current generating device 1 is controlled to detect current values of the first sample 4 and the second sample 5, and the two temperature measuring devices 3 are controlled to measure temperature values of the first sample 4 and the second sample 5, and current carrying capacities of the first sample 4 and the second sample 5 are compared according to the detected current values and temperature values of the first sample 4 and the second sample 5. The data processing device 2 also sends a regulation signal to the current generating device 1 according to the test requirements, so that the current generating device 1 applies different currents to the first sample 4 and the second sample 5.
In summary, in this embodiment, environmental factors when the first sample and the second sample are laid are controlled, the difference in structure and parameters between the first sample and the second sample and the laying mode are used as research factors, and then the current-carrying capacities of the first sample and the second sample are compared according to the current values and the temperature values of the first sample and the second sample, so that the current-carrying capacities of the first sample and the second sample can be accurately compared, and further the influence of the difference between the first sample and the second sample on the current-carrying capacity can be accurately grasped.
The embodiment of the device is as follows:
this embodiment has also proposed a buried cable current-carrying capacity test device, see fig. 2, the buried cable current-carrying capacity test device includes: a current generating device 1, a data processing device 2 and two temperature measuring devices 3. The current generating device 1 is arranged between the second end of the first sample 4 and the second end of the second sample 5, the first end of the first sample 4 is connected with the first end of the second sample 5, the first sample 4 and the second sample 5 are directly buried and arranged on a test site 8, environmental parameters of the test site 8 are within a preset range, the first sample 4 and the second sample 5 are different in structure and/or parameters, and/or the first sample and the second sample are different in arrangement mode.
Specifically, the environmental parameter includes at least one of: soil thermal resistivity, soil temperature and wind speed. Selecting a to-be-selected area in a test field 8, detecting soil thermal resistance coefficients, soil temperature and wind speed of a plurality of different positions of the to-be-selected area through an environmental parameter measuring device 6 to judge whether the soil thermal resistance coefficients, the soil temperature and the wind speed of all the positions of the to-be-selected area are controlled within a preset range, determining the to-be-selected area as the test field 8 if the soil thermal resistance coefficients, the soil temperature and the wind speed of all the positions of the to-be-selected area are controlled within the preset range, and reselecting the test field 8 if the soil thermal resistance coefficients, the soil temperature and the wind speed of all the positions of the to-be-selected area are not controlled within the preset range.
The first sample 4 and the second sample 5 each comprise: a cable body. The parameters of the first sample 4 and the second sample 5 differ including: the cable body model is different. The structural differences between the first sample 4 and the second sample 5 include: at least one of the samples is provided with an attachment structure, the attachment structure being of a different structure when the sample is provided with the attachment structure; wherein the auxiliary structure comprises at least one of the following: the cable joint, the conduit and the cable body are provided with armor and metal shielding layer connecting sections.
Specifically, conductor connection sections were made at both ends of the cable body in each sample. The difference between the first sample 4 and the second sample 5 can be expressed in: the cable bodies are different in model; one of the cable bodies is provided with an auxiliary structure, and the other cable body is not provided with the auxiliary structure; the attachment structures on the two cable bodies are different, etc. The cable body can be provided with a cable connector, can also be provided with a conduit, and can also be provided with an armor and metal shielding layer connecting section.
The first sample and the second sample are laid differently, and the laying method comprises the following steps: the backfill materials are different, the backfill material distribution modes are different, and the covers of the grooves after backfilling are different; two grooves are formed in the test field 8, the first sample and the second sample are laid in the two grooves in a one-to-one correspondence mode, and each groove can be used for backfilling after the samples are laid. Specifically, the two grooves are backfilled after the first sample and the second sample are placed in the two grooves in a one-to-one correspondence manner, the backfilling materials can be different, the distribution mode of the backfilling materials can be different, and the covering of the backfilled grooves can be different. Wherein, backfill material distribution mode can include: the volume, shape, etc. of the backfill material. To avoid the effects of light, a cover may be placed over the backfill material after backfilling.
Two temperature measuring devices 3 are respectively arranged at the corresponding structural positions of the first sample 4 and the second sample 5, and each temperature measuring device 3 is used for measuring the temperature of the corresponding sample. Specifically, before the first sample 4 and the second sample 5 are laid on the test site 8, the temperature of the corresponding samples is measured by the two temperature measuring devices 3, and if the deviation of the temperature measurement values at the same structure of the first sample 4 and the second sample 5 exceeds the preset control range or is obviously abnormal, the temperature measuring devices 3 are reset on the first sample 4 and the second sample 5 until the deviation of the temperature at the same structure of the first sample 4 and the second sample 5 is controlled within the preset control range.
The data processing device 2 is electrically connected with the current generating device 1 and the two sample temperature measuring devices 3, the data processing device 2 is used for controlling the current generating device 1 to apply current to the first sample 4 and the second sample 5, after a preset time interval, the current generating device 1 is controlled to detect the current values of the first sample 4 and the second sample 5, the two temperature measuring devices 3 are controlled to measure the temperature values of the first sample 4 and the second sample 5, and the current carrying capacity of the first sample 4 and the current carrying capacity of the second sample 5 are compared according to the detected current values and temperature values of the first sample 4 and the second sample 5.
In specific implementation, the data processing device 2 may store and display the data, and may further send a control signal to the current generation device 1 according to a preset test requirement, so that the current generation device 1 applies different currents to the first sample 4 and the second sample 5 according to the control signal. In specific implementation, the preset time may be determined according to actual conditions, and this embodiment does not limit this.
The method for testing the current-carrying capacity of the directly-buried cable has the advantages, so the device for testing the current-carrying capacity of the directly-buried cable also has corresponding technical effects.
The principle of the method and the device for testing the current carrying capacity of the buried cable in the invention is the same, and the relevant points can be referred to each other.
It should be noted that in the description of the present invention, the terms of direction or positional relationship indicated by the terms "upper", "lower", "left", "right", "inner", "outer", etc. are based on the directions or positional relationships shown in the drawings, which are only for convenience of description, and do not indicate or imply that the device or element must have a specific orientation, be constructed in a specific orientation, and be operated, and thus, should not be construed as limiting the present invention.
Furthermore, it should be noted that, in the description of the present invention, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.
It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.
Claims (10)
1. A method for testing the current carrying capacity of a directly-buried cable is characterized by comprising the following steps:
a selecting step, namely determining a test site, wherein the environmental parameters of the test site are within a preset range;
a laying step of laying a first sample and a second sample on the test field, wherein the first sample and the second sample have different structures and/or parameters and/or are laid in different ways;
and a testing step, namely applying current to the first sample and the second sample, detecting the current value and the temperature value of the first sample and the second sample after a preset time interval, and comparing the current carrying capacity of the first sample and the second sample according to the detected current value and temperature value of the first sample and the second sample.
2. The method for testing current carrying capacity of a buried cable according to claim 1, wherein the selecting step further comprises:
a first determining substep of determining the dimensions of the test site based on the specifications of the first and second samples;
selecting a continuous soil area with similar soil components, flat surface and no underground heat source or cable line facility as a to-be-selected area;
a measuring substep, measuring environmental parameters at different positions in the region to be selected;
if the standard deviation of the environmental parameters at each position of the to-be-selected area is within the preset range, determining the to-be-selected area as the test field;
and if the standard deviation of the environmental parameters at the positions of the to-be-selected area exceeds the preset range, repeating the second determining substep and the measuring substep until the standard deviation of the environmental parameters at the positions of the to-be-selected area is within the preset range.
3. The method for testing current carrying capacity of a buried cable according to claim 2, wherein the environmental parameter comprises at least one of: soil thermal resistivity, soil temperature and wind speed.
4. The buried cable current carrying capacity test method according to claim 2, wherein in the first determining substep,
determining the greater of the length of the first sample and the length of the second sample as the length of both sample regions;
determining the larger of the laying width required for the first sample and the laying width of the second sample as the width of two sample areas;
and determining the size of the test site according to the length and the width of the two sample areas and the requirement of the reserved site of the test work.
5. The method for testing current carrying capacity of a buried cable according to claim 1, wherein the laying step further comprises:
a mounting substep of mounting a temperature measuring device on each of the first sample and the second sample;
a detection sub-step of detecting the temperature at the same structure of the first sample and the second sample;
if the temperature deviation of the same structure of the first sample and the second sample exceeds a preset control range, repeating the installation substep and the detection substep until the temperature deviation of the same structure of the first sample and the second sample is within the preset control range;
and in the sub-step of direct burial laying, two grooves are dug in the test site, the first sample and the second sample are respectively placed in the two dug grooves, and the two grooves are backfilled.
6. The method for testing current carrying capacity of a buried cable according to claim 5, wherein in the laying step,
the first sample and the second sample each comprise: a cable body;
the parameters of the first sample and the second sample being different include: the models of the cable bodies are different;
the first and second samples differing in structure include: at least one of the samples is provided with an attachment structure, the attachment structure being of a different structure when the sample is provided with the attachment structure; wherein the attachment structure comprises at least one of: the cable joint, the conduit and the cable body are provided with armor and metal shielding layer connecting sections;
the different laying modes of the first sample and the second sample comprise: the backfill materials are different, the backfill material distribution modes are different, and the covers of the grooves after backfill are different.
7. The buried cable current carrying capacity test method according to claim 5 or 6, wherein in the buried cable sub-step,
and detecting the temperature of the same structure of the first sample and the second sample, if the temperature deviation of the same structure of the first sample and the second sample exceeds the preset control range, removing the fault or digging two grooves in the test site again, respectively placing the first sample and the second sample into the two dug grooves, and backfilling the two grooves.
8. The method for testing the current-carrying capacity of the buried cable according to claim 1, wherein in the testing step,
connecting a first end of the first sample with a first end of the second sample, installing a current generating device between a second end of the first sample and a second end of the second sample, applying current to the first sample and the second sample through the current generating device, and detecting current values of the first sample and the second sample through the current generating device.
9. The utility model provides a buried cable current-carrying capacity test device which characterized in that includes: the device comprises a current generating device (1), a data processing device (2) and two temperature measuring devices (3); wherein the content of the first and second substances,
the current generating device (1) is used for being arranged between a second end of a first sample (4) and a second end of a second sample (5), the first end of the first sample (4) is connected with the first end of the second sample (5), the first sample (4) and the second sample (5) are directly buried in a test field (8), the environmental parameter of the test field (8) is within a preset range, the structure and/or the parameter of the first sample (4) and the second sample (5) are different, and/or the laying mode of the first sample and the second sample is different;
the two temperature measuring devices (3) are respectively arranged at the corresponding structural positions of the first sample (4) and the second sample (5), and each temperature measuring device (3) is used for measuring the temperature of the corresponding sample;
the data processing device (2) is electrically connected with the current generating device (1) and the two temperature measuring devices (3) and is used for controlling the current generating device (1) to apply current to the first sample (4) and the second sample (5), controlling the current generating device (1) to detect the current values of the first sample (4) and the second sample (5) and controlling the two temperature measuring devices (3) to measure the temperature values of the first sample (4) and the second sample (5) after a preset time interval, and comparing the current carrying capacity of the first sample (4) and the second sample (5) according to the detected current values and temperature values of the first sample (4) and the second sample (5).
10. The buried cable current carrying capacity testing device according to claim 9,
the environmental parameter includes at least one of: soil thermal resistivity, soil temperature and wind speed;
the first sample (4) and the second sample (5) each comprise: a cable body;
the parameters of the first sample (4) and the second sample (5) being different comprise: the models of the cable bodies are different;
the first sample (4) and the second sample (5) differ in structure by: at least one of the samples is provided with an attachment structure, the attachment structure being of a different structure when the sample is provided with the attachment structure; wherein the attachment structure comprises at least one of: the cable joint, the conduit and the cable body are provided with armor and metal shielding layer connecting sections;
the different laying modes of the first sample and the second sample comprise: the backfill materials are different, the backfill material distribution modes are different, and the covers of the grooves after backfilling are different; two grooves are formed in the test field (8), the first samples and the second samples are laid in the two grooves in a one-to-one correspondence mode, and each groove can be used for backfilling after the samples are laid.
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