CN111721801A - Heat conduction sensor based on heat conduction gradient - Google Patents
Heat conduction sensor based on heat conduction gradient Download PDFInfo
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- CN111721801A CN111721801A CN202010430728.3A CN202010430728A CN111721801A CN 111721801 A CN111721801 A CN 111721801A CN 202010430728 A CN202010430728 A CN 202010430728A CN 111721801 A CN111721801 A CN 111721801A
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- 239000004020 conductor Substances 0.000 claims description 45
- 238000005259 measurement Methods 0.000 claims description 10
- 238000009413 insulation Methods 0.000 claims description 8
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical group [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims description 6
- 238000010438 heat treatment Methods 0.000 claims description 6
- 238000012544 monitoring process Methods 0.000 abstract description 24
- 238000001514 detection method Methods 0.000 abstract description 13
- 230000008901 benefit Effects 0.000 abstract description 6
- 230000007547 defect Effects 0.000 abstract description 3
- 238000000034 method Methods 0.000 description 10
- 238000009529 body temperature measurement Methods 0.000 description 7
- 239000013307 optical fiber Substances 0.000 description 6
- 230000008859 change Effects 0.000 description 4
- 238000010586 diagram Methods 0.000 description 4
- 239000000126 substance Substances 0.000 description 4
- 238000012546 transfer Methods 0.000 description 3
- 238000005516 engineering process Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 230000002093 peripheral effect Effects 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 230000032683 aging Effects 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N25/00—Investigating or analyzing materials by the use of thermal means
- G01N25/18—Investigating or analyzing materials by the use of thermal means by investigating thermal conductivity
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N25/00—Investigating or analyzing materials by the use of thermal means
- G01N25/20—Investigating or analyzing materials by the use of thermal means by investigating the development of heat, i.e. calorimetry, e.g. by measuring specific heat, by measuring thermal conductivity
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Abstract
The invention relates to the technical field of sensors, in particular to a heat conduction sensor based on heat conduction gradient, which is used for detecting a cable. The invention can realize long-distance regional temperature detection through heat conduction, overcomes the defects of point type and line type temperature detection of the power cable, provides a detection means for the field of long-distance whole-course monitoring of the power cable and the like, can better realize the long-distance temperature monitoring of the power cable, provides necessary guarantee for the safety application and the danger alarm of the power cable, and has great economic benefit and social significance.
Description
Technical Field
The invention relates to the technical field of sensors, in particular to a heat conduction sensor based on heat conduction gradient.
Background
When the power cable operates, the load current is large, and due to the existence of the wire resistance, the heat W of the wire is I2Rt, and the cable core gradually heats up along with the time. If the cable is in a use state with overhigh temperature for a long time, the aging of the cable insulation layer is accelerated, and finally, electric power accidents such as fire, short circuit, explosion and the like are caused.
Currently, for the evaluation of the operation state of the power cable, the working temperature of the cable during operation is mainly monitored. In the on-line monitoring of the operating temperature of the cable, two methods are mainly adopted: (1) monitoring the temperature in a contact manner; (2) non-contact temperature monitoring is of two types. The contact temperature monitoring method can be divided into the following steps according to the distribution condition of the temperature sensors: point distributed temperature monitoring and line distributed temperature monitoring.
The point distributed temperature monitoring adopts traditional temperature sensors such as a thermocouple, a thermistor and a digital temperature sensor to carry out local temperature measurement on the cable, and is generally arranged in a key monitoring area of an electric power operation line, such as a cable joint; the method has the advantages of high temperature measurement precision, low cost and simple installation; the disadvantage is that temperature can only be measured point by point and temperature monitoring can not be operated for a long distance. The line distributed temperature monitoring mainly adopts a distributed optical fiber sensor and an optical fiber grating sensor, and has the advantages that all other temperature measurement technologies do not have.
Currently, there are two types of touch sensor mounting methods: one is laid on the surface of the cable along the cable run. The method can measure the temperature data of the whole cable, but the cost is high and the engineering quantity is large due to the long-distance laying; the other method is that the optical fiber temperature sensor is arranged inside the cable and forms a whole with the cable, the method can influence the measurement accuracy of the system when the optical fiber sensor is extruded or bent seriously in the process of manufacturing and laying the cable, and the built-in optical fiber cannot be repaired once being damaged. Meanwhile, related researches show that the distributed optical fiber temperature sensor has great superiority, but has a long distance from industrial practicability. The non-contact temperature monitoring mainly adopts an infrared thermal imaging technology, the measurement is convenient, and the response time is short. At present, an electric power company generally adopts an infrared thermal imager to measure the temperature of cable equipment during line patrol. The method can only carry out point-type measurement and cannot carry out full-line online monitoring.
In view of the above drawbacks, a need exists in the art for a thermal conductivity sensor based on thermal conductivity gradient, which greatly improves the range of point-distributed temperature measurement and provides a necessary detection sensor for long-distance temperature monitoring of a power cable.
Disclosure of Invention
The invention aims to provide a heat conduction sensor based on heat conduction gradient, which greatly improves the range of point-distributed temperature measurement and provides a necessary detection sensor for long-distance temperature monitoring of a power cable.
In order to achieve the above object, the present invention provides a thermal conductivity sensor based on a thermal conductivity gradient, which is used for detecting a cable, the cable including a heat insulating layer and a conductor, wherein a plurality of heat conducting strips are disposed between the heat insulating layer and the conductor, the heat conducting strips are connected to the conductor through the heat insulating layer, and a gap of a predetermined distance is formed between the heat conducting strips.
Preferably, the conductor performs a thermal conductivity measurement as disclosed in:
wherein λ is the thermal conductivity of the conductor, S is the cross-sectional area of the conductor, and T1-T2The temperature difference from the heating origin to the measurement point is shown as D, which is the length of the conductor.
Preferably, the conductor is a copper wire, and the thermal conductivity of the copper wire is 401W/(m.k).
Preferably, the outer side wall of the heat conducting sheet is provided with a temperature sensor interface.
Preferably, the outer side of the heat conducting fin is provided with a plastic locking device, so that an external sensor can be reliably contacted with the heat conducting fin through the temperature sensor interface.
Preferably, the heat conducting fins are uniformly distributed in the heat insulating layer.
Preferably, the conductor has a cylindrical structure.
Preferably, the outer layer and the positions of the two ends of the conductor are wrapped by heat insulating layers.
The invention provides a heat conduction sensor based on heat conduction gradient, which has the following advantages:
1. in order to detect the temperature change of the surface of the cable, a plurality of conducting strips are designed on the surface of the cable and are connected with the conductor through a heat insulating layer, so that the distance between a temperature rise point and a temperature measuring point can be calculated according to the heat conduction gradient of the conductor in order to detect the temperature change of a circuit at the periphery, and a data basis is provided for a power cable temperature monitoring system to judge a fault point;
2. the long-distance regional temperature detection can be realized through heat conduction, the defects of point type and line type temperature detection of the power cable are overcome, a detection means is provided for the field of long-distance whole-course monitoring of the power cable and the like, so that the long-distance temperature monitoring of the power cable can be better realized, necessary guarantee is provided for safe application and danger alarm of the power cable, and great economic benefit and social significance are realized.
Drawings
FIG. 1 is a schematic structural diagram of a thermal conductivity sensor based on a thermal conductivity gradient according to the present invention;
fig. 2 is a schematic structural diagram of a heat-conducting sensor externally connected with a temperature sensor according to the present invention.
Detailed Description
In order to make the technical solutions of the present invention better understood, those skilled in the art will now describe the present invention in further detail with reference to the accompanying drawings.
Referring to fig. 1-2, fig. 1 is a schematic structural diagram of a thermal conductivity sensor based on a thermal conductivity gradient according to the present invention; fig. 2 is a schematic structural diagram of a heat-conducting sensor externally connected with a temperature sensor according to the present invention.
As shown in fig. 1-2, the present invention provides a thermal conductivity sensor based on a thermal conductivity gradient for detecting a cable, the cable including a thermal insulation layer 100 and a conductor 200, wherein a plurality of thermal conductive sheets 300 are disposed between the thermal insulation layer 100 and the conductor 200, the thermal conductive sheets 300 are connected to the conductor 200 through the thermal insulation layer 100, and the thermal conductive sheets 300 are spaced apart from each other by a predetermined distance.
The heat conducting fins 300 in this embodiment are uniformly distributed in the insulating layer 100, the conductor 200 is in a cylindrical structure, and the outer layer and the two ends of the conductor 200 are wrapped by the insulating layer.
In order to detect the temperature variation on the surface of the cable, a plurality of conducting strips 300 are designed on the surface of the cable, the conducting strips 300 are connected with the conductors 200 through the insulating layer 100, and a temperature sensor measuring interface is designed at the middle point of the invention in order to facilitate the peripheral detection circuit to detect the temperature variation.
Specifically, in the present embodiment, the measurement of the heat conduction of the conductor 200 is disclosed as follows:
wherein λ is the thermal conductivity of the conductor, S is the cross-sectional area of the conductor, and T1-T2The temperature difference from the heating origin to the measurement point is shown as D, which is the length of the conductor.
The invention can calculate the distance between the temperature rise point and the temperature measurement point according to the gradient of heat conduction of the conductor, thereby providing data basis for the power cable temperature monitoring system to judge the fault point.
The conductor in this embodiment is a copper wire, and the thermal conductivity of the copper wire is preferably 401W/(m · k). The copper with high heat conductivity coefficient is used as the conductor of the sensor, in order to reduce the loss of heat in the conduction process and reduce the sectional area of the conductor, the conductor is designed into a small cylinder, and the outer layer and two ends of the conductor are packaged by heat insulating materials.
In addition, in order to fix the external sensor, a plastic locking device is arranged on the outer side of the heat conducting fin, so that the external sensor can be reliably contacted with the heat conducting fin through the temperature sensor interface.
The working principle of the invention is as follows:
the heat conductivity coefficient of the material is one of important heat and humidity characteristics of the material, the heat conductivity coefficients of different substances are different, and the heat conductivity coefficient of the same substance is related to factors such as the structure, the density, the humidity, the temperature, the pressure and the like of the same substance. Under the same physical conditions, the thermal conductivity of the same substance is determined.
In this embodiment, the measurement of the heat conduction of the conductor is disclosed as follows:
wherein △ Q is the heat transferred from one end of the wire to the other, △ T is the time of heat transfer, λ is the thermal conductivity, S is the cross-sectional area of the conductor, l is the length of the conductor, T1Temperature of origin of heat generation, T2To measure the temperature of the spot, T1-T2The temperature difference from the heating origin to the measurement point. From the above equation, it can be seen that the temperature difference of the conductor is inversely proportional to the heat transfer length of the conductor. Meanwhile, the insulating layer, the sheath layer and the like of the power cable are homogeneous, and the thermal conductivity of the power cable is also average. Because the cable dissipates heat quickly, the heat of the heating point is transmitted along the conducting wire in a short distance when the cable runs. The invention designs a heat conduction sensor based on heat conduction, which can transfer the temperature of a heating point to a temperature monitoring point in a long distance. Simplifying the formula (1):
T1-T2＝k·l (2)
it can be seen from (2) that the farther the transmission distance is, the larger the temperature difference is. When in use, the distance between the two points can be measured only by measuring the temperature difference between the two points.
In summary, in order to detect the temperature change on the surface of the cable, a plurality of conducting strips are designed on the surface of the cable, the conducting strips are connected with the conductors through the heat insulating layer, and in order to facilitate the peripheral detection of the temperature change of the circuit, the distance between the temperature rise point and the temperature measurement point can be calculated according to the gradient of heat conduction of the conductors, so that a data basis is provided for the power cable temperature monitoring system to judge the fault point; the long-distance regional temperature detection can be realized through heat conduction, the defects of point type and line type temperature detection of the power cable are overcome, a detection means is provided for the field of long-distance whole-course monitoring of the power cable and the like, so that the long-distance temperature monitoring of the power cable can be better realized, necessary guarantee is provided for safe application and danger alarm of the power cable, and great economic benefit and social significance are realized.
The construction, features and functions of the present invention are described in detail in the embodiments illustrated in the drawings, which are only preferred embodiments of the present invention, but the present invention is not limited by the drawings, and all equivalent embodiments modified or changed according to the idea of the present invention should fall within the protection scope of the present invention without departing from the spirit of the present invention covered by the description and the drawings.
Claims (8)
1. A heat conduction sensor based on a heat conduction gradient is used for detecting a cable, the cable comprises a heat insulation layer and a conductor, and is characterized in that a plurality of heat conducting fins are arranged between the heat insulation layer and the conductor, the heat conducting fins are connected with the conductor through the heat insulation layer, and intervals with preset distances are arranged between the heat conducting fins.
2. The thermal conductivity gradient-based thermal conductivity sensor of claim 1, wherein the conductor performs a measure of thermal conductivity as disclosed by:
wherein λ is the thermal conductivity of the conductor, S is the cross-sectional area of the conductor, and T1-T2The temperature difference from the heating origin to the measurement point is shown as D, which is the length of the conductor.
3. The thermal conductivity gradient-based thermal conductivity sensor of claim 1, wherein the conductor is a copper wire having a thermal conductivity of 401W/(m-k).
4. The thermal conductivity gradient-based thermal conductivity sensor of claim 1, wherein an outer sidewall of the thermal conductive sheet is provided with a temperature sensor interface.
5. The thermal conductivity gradient-based thermal conductivity sensor of claim 4, wherein the thermal conductivity sheet is provided with a plastic locking device on the outer side thereof, so that an external sensor can be reliably contacted with the thermal conductivity sheet through the temperature sensor interface.
6. The thermal conductivity gradient-based thermal conductivity sensor of claim 1, wherein the thermally conductive sheet is uniformly distributed within the thermally insulating layer.
7. The thermal conductivity gradient-based thermal conductivity sensor of claim 1, wherein the conductor is in a cylindrical configuration.
8. The thermal conductivity gradient-based thermal conductivity sensor of claim 1, wherein the outer layer of the conductor and the two ends are wrapped with a thermal insulation layer.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010430728.3A CN111721801A (en) | 2020-05-20 | 2020-05-20 | Heat conduction sensor based on heat conduction gradient |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202010430728.3A CN111721801A (en) | 2020-05-20 | 2020-05-20 | Heat conduction sensor based on heat conduction gradient |
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Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN201126384Y (en) * | 2007-12-17 | 2008-10-01 | 国网武汉高压研究院 | Power cable conductor temperature measurement apparatus |
| CN201302491Y (en) * | 2008-10-31 | 2009-09-02 | 国网武汉高压研究院 | Loop sensor for measuring temperature of cable conductor |
| CN102494793A (en) * | 2011-12-01 | 2012-06-13 | 国网电力科学研究院 | Temperature thermocouple for high-voltage and ultrahigh-voltage power cable |
| CN204855026U (en) * | 2015-07-16 | 2015-12-09 | 河北省电力勘测设计研究院 | A distributed sensor arrangement structure for cable intermediate head temperature measurement |
| CN105698963A (en) * | 2016-03-25 | 2016-06-22 | 中国电力科学研究院 | Cable conductor temperature measurement system based on acoustic surface wave temperature sensor and algorithm thereof |
| CN207472445U (en) * | 2017-12-03 | 2018-06-08 | 汪成 | A kind of space exploration device of multiple spot monitoring cable temperature |
| CN108414100A (en) * | 2018-02-23 | 2018-08-17 | 华南理工大学 | A kind of thermocouple optimization placement method for testing measurement cable body Wen Sheng |
| CN208672178U (en) * | 2018-08-03 | 2019-03-29 | 江苏方天电力技术有限公司 | A kind of contactless spectrum temperature measuring equipment of for transformer winding |
-
2020
- 2020-05-20 CN CN202010430728.3A patent/CN111721801A/en active Pending
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN201126384Y (en) * | 2007-12-17 | 2008-10-01 | 国网武汉高压研究院 | Power cable conductor temperature measurement apparatus |
| CN201302491Y (en) * | 2008-10-31 | 2009-09-02 | 国网武汉高压研究院 | Loop sensor for measuring temperature of cable conductor |
| CN102494793A (en) * | 2011-12-01 | 2012-06-13 | 国网电力科学研究院 | Temperature thermocouple for high-voltage and ultrahigh-voltage power cable |
| CN204855026U (en) * | 2015-07-16 | 2015-12-09 | 河北省电力勘测设计研究院 | A distributed sensor arrangement structure for cable intermediate head temperature measurement |
| CN105698963A (en) * | 2016-03-25 | 2016-06-22 | 中国电力科学研究院 | Cable conductor temperature measurement system based on acoustic surface wave temperature sensor and algorithm thereof |
| CN207472445U (en) * | 2017-12-03 | 2018-06-08 | 汪成 | A kind of space exploration device of multiple spot monitoring cable temperature |
| CN108414100A (en) * | 2018-02-23 | 2018-08-17 | 华南理工大学 | A kind of thermocouple optimization placement method for testing measurement cable body Wen Sheng |
| CN208672178U (en) * | 2018-08-03 | 2019-03-29 | 江苏方天电力技术有限公司 | A kind of contactless spectrum temperature measuring equipment of for transformer winding |
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Application publication date: 20200929 |