WO2013082130A2

WO2013082130A2 - Temperature-monitoring system

Info

Publication number: WO2013082130A2
Application number: PCT/US2012/066818
Authority: WO
Inventors: Aiqi WANG; Qi Su; Zhiguo WEN
Original assignee: 3M Innovative Properties Company
Priority date: 2011-11-30
Filing date: 2012-11-28
Publication date: 2013-06-06
Also published as: WO2013082130A3; CN202329831U; TW201333436A

Abstract

The present invention provides a temperature-monitoring system for monitoring a temperature T1 of a jacketed body. The system comprises a first temperature-measuring unit, a second temperature-measuring unit and a control unit. The first temperature-measuring unit is configured to measure a surface temperature T2 of the jacket and send out the measured value of the surface temperature T2; the second temperature-measuring unit is configured to measure an environment temperature T3 of a space where the jacket is located and send out the measured value of the environment temperature T3; the control unit is configured to receive the measured value of the surface temperature T2 from the first temperature-measuring unit and the measured value of the environment temperature T3 from the second temperature-measuring unit, and determine a value of the temperature T1 of the body based on the measured value of the surface temperature T2 and the measured value of the environment temperature T3.

Description

TEMPERATURE-MONITORING SYSTEM

TECHNICAL FIELD

The present invention relates to a temperature-monitoring system. In particular, the present invention relates to a temperature-monitoring system that can be used to measure the temperature of a jacketed or sheathed body, such as a temperature-monitoring system for monitoring the temperature of a cable conductor wrapped in a cable sheath.

TECHNICAL BACKGROUND

In industrial or daily life applications, it is often required to monitor the temperature of a jacketed or sheathed body to learn the temperature of the body. For example, in a power sector, the cable conductor of a high- voltage line is typically wrapped tightly within a thick insulation sheath. The temperature of the conductor will increase when powered, and sometimes the temperature may extend out of the safe range, therefore it is necessary to monitor the temperature of the conductor. Particularly at a cable joint, the temperature may increase due to poor contact, which would result in an increase in resistance; this may cause damage to the joint from overheating, which may evolve into an accident, and under serious conditions, even a fire, if not handled in a timely manner.

Therefore, it is extremely necessary to conduct a real-time monitoring of the temperature of a cable conductor, particularly the temperature of the conductor at a cable joint.

Currently, a temperature-monitoring system similar to that described in Chinese patent no. 201020275058.2 is typically used to monitor the temperature of a cable conductor. The system comprises a temperature-monitoring module, a temperature-monitoring terminal, and a data- management module. The temperature-monitoring module typically comprises a temperature sensor and a wireless data-transmitting unit. The temperature sensor is attached directly onto the surface of the area of a high- voltage power installation to be measured to collect temperature data. The wireless data-transmitting unit is connected to the temperature sensor and used to receive the temperature data and send the same to the temperature-monitoring terminal. The temperature- monitoring terminal is wirelessly connected with the temperature-monitoring module to receive the temperature data. The temperature-management module is connected to the temperature-monitoring module to receive the temperature data and perform statistics, analysis, and processing of the same. The processing results will be displayed and used to determine whether a warning should be sent out.

However, currently such temperature-monitoring systems have more or less the flaws as described below, which make it very difficult for the current systems to satisfy the temperature- measuring requirements in respect to accuracy, and to forecast in an accurate way the safety issues that may be caused by temperature. 1. The monitoring is only performed on the temperature of the outer surface or the sheath of a cable; however, such temperature is different from that of the inner conductor of the cable and it would not reflect the real working temperature of the cable. Particularly in the summer or winter, the difference of heat exchange between the cable outer surface and the environment (e.g., the surrounding air) is relatively larger and thus the difference between the cable surface temperature and the inner conductor temperature could be very big.

2. The monitoring is only performed on the temperature of the outer surface of a cable, and the system would send out a warning message when the temperature is higher than a predetermined value; however, in fact, if a cable works consecutively in the range that the temperature is slightly lower than the pre-determined value, the aging of the cable sheath insulation would be subjected to a fundamental change and this would result in safety risks. Current temperature-monitoring systems could not reflect the aging of the insulation of a cable resulting from a long time working at a high temperature, and accordingly, could not give a warning on possible safety issues based thereon.

3. The battery, sensor, and controller or a message transmitting means of the temperature-measuring device are assembled as an integral body and thus the integral body as a whole would have to be replaced when the battery runs out of power, which is a big waste.

Therefore, there is a need to develop a temperature-monitoring system that can reflect the real temperature of the inner conductor of a cable. More advantageously, the system cannot only give a warning message based on the temperature of the inner conductor of the cable, but also give a warning message based on the aging of the cable due to temperature.

SUMMARY

It is an objective of at least one embodiment of the present invention to provide a temperature-monitoring system that can, as much as possible, reflect the real temperature of a jacketed body, such as an inner conductor wrapped in an insulation sheath. Preferably, when the measured or calculated real temperature of the body is higher than a pre-determined threshold, the system can send out a warning message. More preferably, the system cannot only give a warning message based on the temperature of the jacketed body (for example, an inner conductor of the cable), but also give a warning message based on the aging of the jacket due to temperature.

Therefore, according to at least one embodiment of the present invention, a temperature- monitoring system for monitoring a temperature Tl of a jacketed body is provided. The system comprises a first temperature-measuring unit, a second temperature-measuring unit and a control unit, wherein the first temperature-measuring unit comprises a first temperature sensor and is configured to measure a surface temperature T2 of the jacket, and to send out the measured value of the surface temperature T2; the second temperature-measuring unit comprises a second temperature sensor and is configured to measure an environment (e.g., air) temperature T3 of a space where the jacket is located and to send out the measured value of the environment temperature T3; the control unit is configured to receive the measured value of the surface temperature T2 from the first temperature-measuring unit and the measured value of the environment temperature T3 from the second temperature-measuring unit, and to determine a value of the temperature Tl of the body based on the measured value of the surface temperature T2 and the measured value of the environment temperature T3.

It should be understood that, when the body is at the same temperature state, the heat exchange efficiency of the jacket with the environment would be high in winter as the environment temperature is lower, which would result in the surface temperature of the jacket being relatively lower; but the heat exchange efficiency of the jacket with the environment would be low in summer as the environment temperature is higher, which would result in the surface temperature of the jacket being relatively higher. Therefore, there is a certain difference between the jacket surface temperature and the actual body temperature, and the difference would not be the same at different environment temperatures. The temperature-monitoring system of the present invention is designed to obtain the body temperature Tl based on not only the jacket surface temperature Tl, but also the environment temperature T3. Compared with the prior art that the body temperature is approximated as the temperature of the jacket wrapping the body, or calculated to being an approximate value using the jacket temperature, the body temperature Tl attained using the temperature-monitoring system of the present invention can reflect a more real temperature of the body.

In at least one embodiment of the present invention, the control unit comprises a lookup table, and the lookup table contains information of a specific value of the body temperature Tl corresponding to a certain value of the surface temperature T2 under a certain range of the environment temperature T3. As such, when the control unit receives a surface temperature T2, it can look up directly in the lookup table to obtain a corresponding body temperature Tl by taking into account of the environment temperature T3 at that time. Optionally, surface temperatures T2 and the body temperatures Tl corresponding to the surface temperatures T2 can be measured respectively using pre-simulations under the same range of the environment temperature T3. Further, different ranges of environment temperature T3 can be determined with respect to different seasons or different exterior environments to obtain multiple groups of surface temperatures T2 and the body temperatures Tl corresponding respectively to the surface temperatures T2.

In at least one embodiment of the present invention, the control unit is preferably configured to make a comparison between the value of the temperature Tl and a first pre-determined threshold Ql, and send out a first warning message if the value of the temperature Tl is greater than the first pre-determined threshold Ql . In at least one embodiment of the present invention, preferably, the control unit further comprises a time module configured to count a duration of time that the value of the surface temperature T2 is consecutively above a second pre-determined threshold Q2. The first predetermined threshold Ql is greater than the second pre-determined threshold Q2. The control unit is further configured to send out a second warning message if the duration of time is greater than a third pre-determined threshold Q3. In this way, the aging of the jacket can be substantially learned by monitoring the duration of time that the surface temperature of the jacket is higher than the second threshold Q2. Therefore, even if the body temperature Tl is in the safe range, if the aging of the jacket has been up to an extent that may result in safety concerns, the system would send out a warning in a timely manner.

In at least one embodiment of the present invention, the first temperature-measuring unit further comprises a battery module and a power-monitoring module. The battery module is configured to provide electrical power to the other elements included in the first temperature- measuring unit, and the battery module is assembled with the other elements in a detachable way. The power-monitoring module is configured to monitor the power level in the battery module, and send the measured power level out. The control unit is further configured to be able to receive the measured power level from the first temperature-measuring unit, and send out a third warning message when the power level is lower than a fourth pre-determined threshold Q4. As such, a user can determine that the battery module would need to be replaced based on the warning message that the battery will run out sent out by the temperature-monitoring system.

Further, the battery module is assembled with the other elements in a detachable way and thus the replacement of the battery module can be readily implemented by just taking the battery module away and replacing it with a new one, rather than replacing the whole temperature-measuring unit. Therefore, it is convenient and cost saving.

BRIEF DESCRIPTION OF THE DRAWINGS

For the purpose of clearly describing the technical solutions of the embodiments of the present invention, a brief description of the drawings that will be used to describe the embodiments is provided below. Obviously, such drawings would only be used to exemplify some of the

embodiments of the present invention to a person of ordinary skill in the art, based on such drawings, other drawings may be contemplated with no creative efforts. Further, such drawings should not in any way be construed as limiting the present invention.

Figs, la and lb illustrate schematic structure diagrams of an object, which can be monitored by the temperature-monitoring system according to an embodiment of the present invention;

Fig. 2 illustrates a composition block diagram of the temperature-monitoring system according to the first embodiment of the present invention; Fig. 3 illustrates a composition block diagram of the first temperature-measuring unit of the temperature-monitoring system according to an embodiment of the present invention;

Fig. 4 illustrates a composition block diagram of the control unit of the temperature- monitoring system according to an embodiment of the present invention;

Fig. 5 illustrates a control flow chart of the control unit of the temperature-monitoring system according to an embodiment of the present invention;

Fig. 6 illustrates another control flow chart of the control unit of the temperature-monitoring system according to an embodiment of the present invention;

Fig. 7 illustrates another composition block diagram of the first temperature-measuring unit of the temperature-monitoring system according to an embodiment of the present invention;

Fig. 8 illustrates a composition block diagram of the temperature -monitoring system according to the second embodiment of the present invention.

DETAILED DESCRIPTION

It should be noted that the embodiments below are exemplary illustrations of the present invention, and the features of different embodiments can be combined with each other under the conditions that they are not in conflict with each other. The present invention will be described in detail by referring to the accompanying drawings in combination with particular embodiments.

Figs, la and lb illustrate schematic structure diagrams of an object, which can be monitored by the temperature-monitoring system according to an embodiment of the present invention. The object 10 comprises at least a body 11 and a jacket 12 wrapping the body 11. Typically, the body 11 is wrapped tightly in the jacket 12 such that the body 11 would basically not be exposed if the jacket 12 is not broken. It should be understood that the object 10 may also include other components. For example, the object 10 may be a cable used in the power industry, such as a separate coaxial cable, which is illustrated in Fig. la. The coaxial cable comprises an inner conductor 11a, an outer conductor l ib, an insulation 13 positioned between the inner conductor 11a and the outer conductor

I lb, and an outer insulation shell wrapping the outer conductor 1 lb. In this particular case, the body

I I is most typically the inner conductor 11a, but may in some cases be the outer conductor 1 lb, and the jacket 12 is the outer insulation shell.

In another particular embodiment of the present invention, the object 10 may also be a combined body of a cable and a connector connecting the cable. The temperature-monitoring system of the present invention is particularly useful for monitoring the temperature of a cable at the location of a cable accessory in the power industry, such as the cable at a cable connector, a cable terminal, or a detachable connector, as it is particularly necessary to monitor the temperature of the cable conductor at these locations; for a conventional temperature-measuring method, it would be very difficult to accurately measure the temperature of the cable conductor as it is wrapped by the cable accessory. In this case, the body 11 is the cable conductor that is wrapped by the outer insulation shell of the cable, while the jacket 12 is the insulation protection layer of the cable accessory wrapping the outer insulation layer of the cable.

Fig. 2 illustrates a composition block diagram of the temperature-monitoring system according to the first embodiment of the present invention. The temperature-monitoring system 100 comprises a first temperature-measuring unit 20, a second temperature-measuring unit 30, a control unit and a terminal device 50.

The first temperature-measuring unit 20 is configured to measure a surface temperature T2 of the jacket 12 of the object 10, and send out the measured value of the surface temperature T2. The second temperature-measuring unit 30 is configured to measure an environment temperature T3 of a space where the object 10 is located, and send out the measured value of the environment temperature T3. The control unit 40 is configured to receive the measured value of the surface temperature T2 from the first temperature-measuring unit 20 and the measured value of the environment temperature T3 from the second temperature-measuring unit 30, and determine a value of the temperature Tl of the body 11 of the object 10 based on the measured value of the surface temperature T2 and the measured value of the environment temperature T3. The terminal device 50 is used to display information from the control unit 40, such as the body temperature Tl and/or the first, second and third warning messages as described below.

Optionally, as illustrated in fig. 3, the first temperature-measuring unit 20 comprises a temperature sensor 201, a micro-controller module 202, and a data-transmitting module 203. The temperature sensor 201 may be a thermocouple or a contact temperature-measuring element, which is in contact with the temperature-measuring point on the jacket 12 of the object 10 by attachment or bonding. The temperature information of the temperature-measuring point is collected and the value of the temperature at the measuring point can be obtained. Of course, the temperature sensor 201 may also be a non-contact temperature-measuring element, such as an infrared thermometer. The measured value of the temperature is transmitted to the micro-controller module 202 by the temperature sensor 201. The temperature will then be subjected to processing of digital -to analogue conversion and/or message amplification by the micro-controller module 202. The data-transmitting module 203 may be a wired or a wireless element having data-transmitting function, and transmits the processed value of the temperature to the control unit 40. With respect to the temperature sensor 201, the micro-controller module 202 and the data-transmitting module 203, to a person of ordinary skill in the art, there are many different particular configurations to carry out such functions. Thus, such particular configurations will not be further described.

Optionally, the second temperature-measuring unit 30 may comprise aforementioned similar modules or configurations included in the first temperature-measuring unit 20. In some

embodiments, the second temperature-measuring unit and the first temperature-measuring unit each may have its own temperature sensor; however, they may share the same micro-controller module 202 and data-transmitting module 203.

Figs. 4-6 illustrate respectively the composition block diagram and the work flow chart of the control unit 40. The control unit 40 will be further described below by referring to figs. 4, 5 and 6. The control unit 40 may comprise a data-receiving module 401 , a data-saving and management module 402, and a data-processing module 403. The data-receiving module 401 is configured to receive the value of the surface temperature T2 and the value environment temperature T3 transmitted from the data-transmitting module 203 of the first temperature-measuring unit 20 and the second temperature-measuring unit 30. The data-saving and management module 402 is used to save the value of the surface temperature T2 , the value of the environment temperature T3 and other information that needs to be saved. The data-processing module 403 is used to process the value of the surface temperature T2 and the value of the environment temperature T3, and determine the body temperature Tl based on a preset rule.

Optionally, the control unit 40 comprises a lookup table, which is saved in the data-saving and management module 402. The lookup table contains information of a specific value of the body temperature Tl corresponding to a certain value of the surface temperature T2 under a certain range of the environment temperature T3. For example, when the environment temperature T3 is at a temperature of about 15 °C, and the surface temperature is 36 °C, then the corresponding body temperature Tl will be 76 °C; when the environment temperature T3 is at a temperature of about 35 °C, and the surface temperature is 44 °C, then the corresponding body temperature Tl will be 78 °C.

Optionally, the lookup table comprises at least three groups of values, wherein each group includes multiple values of the surface temperature T2 and multiple values of the temperature Tl, each value of the body temperature Tl corresponds to one value of the surface temperature T2, the body temperatures Tl and the surface temperatures contained in each group correspond to the same range of the environment temperature T3, but a different group corresponds to a different range of the environment temperature T3. The values of the body temperature Tl and the values of the surface temperaturesT2 in each group may be attained by measuring the temperatures of the body and the jacket respectively by simulations under the same range of the environment temperature T3, and saved in the lookup table. For example, in a simulation, a sample that is substantially identical with the structure and material of the body 10 is produced; however, the body was not wrapped completely by a jacket to facilitate direct measuring of the temperature of the same. Then, under a certain range of environment temperature T3, the body 11 of the object 10 is placed under different temperatures to measure the temperature Tl of the body 11 and the corresponding temperature T2 of the jacket 12. In case that the object 10 is an electric cable, different powers may be applied to the body 11 such that the body 11 can be made to have different temperatures Tl . Optionally, the lookup table comprises three groups of temperature values, wherein the first group of temperature values corresponds to an environment temperature T3 that is greater than a first value Ml, such as 30°C, the second group of temperature values corresponds to an environment temperature T3 that is smaller than a second value M2, such as 10°C, and the third group of temperature values corresponds to an environment temperature T3 that is between the first value Ml and the second value M2, for example, between 10°C and 30°C. Typically, the first value Ml is greater than the second value M2. Of course, the lookup table may also comprise four groups, five groups, or even more groups of temperature values, depending on the different needs.

In some embodiments, as shown in Fig. 5, after the body temperature Tl is attained by the control unit 40, the control unit 40 may further make a comparison between the value of the body temperature Tl and a first pre-determined threshold Ql, and send out a first warning message if the value of the temperature Tl is greater than the first pre-determined threshold Ql to remind the user that the temperature of the object has gone beyond the safety limit. The value of the first threshold Ql depends primarily on the heat-resistant performance of the materials of the body 11 and the jacket 12. For example, for an electric cable, the first threshold Ql can be selected as 90°C.

Optionally, as shown in fig. 4, the control unit 40 may further comprise a time module. The time module is configured to count a duration of time that the value of the surface temperature T2 is consecutively greater than a second pre-determined threshold Q2. As shown in fig. 6, the control unit 40 may make a comparison between each surface temperature T2 and the second threshold Q2. If the surface temperature T2 is greater than the second threshold Q2, the data-processing module 403 of control unit 40 will send the time module 404 an order to make the time module 404 start to count, and transmit the duration of time thus counted in a real time manner to the data-saving and management module 402. If control unit 40 finds that the surface temperature T2 is smaller than the second threshold Q2, and the time module 404 has been in the counting state, the data-processing module 403 will send the time module 404 an order to end the time count and reset the time count records. Otherwise, the time module 404 will not stop counting until an order of ending the count is received. The control unit 40 is further configured to make a comparison using the data-saving and management module 402 between the duration of time from the time module 404 and a third predetermined threshold Q3. If the duration of time from the time module 404 is greater than the third threshold Q3, the control unit 40 will send out a second warning message.

It should be understood that the value of the first threshold Ql is greater than the value of the second threshold Q2, the value of the second threshold Q2 and the value of the third threshold Q3 depend primarily on the ageing resistance of the material of the jacket 12. As such, when a user receives the second warning message, he/she should basically learn the ageing status of the material of the jacket 12, and conduct timely on-site local tests on the jacket 12 to further measure the ageing status of the material of the jacket 12 to determine whether the whole object 10 is required to be replaced in a timely manner.

Optionally, in some other particular embodiments, as shown in fig. 7, the first temperature- measuring unit comprises a temperature sensor 201, a micro-controller module 202, a data- transmitting module 203, a battery module 204 and a power-monitoring module 205. The temperature sensor 201 , the micro-controller module 202 and the data-transmitting module 203 are as described above. The battery module 204 is primarily configured to supply electrical power to other elements included in the first temperature-measuring unit, such as the micro-controller module 202 and the data-transmitting module 203. Preferably, the battery module 203 is assembled with said other elements included in the first temperature-measuring unit 20 in a detachable way. As a result, when the electric power of the battery module 204 runs out, the battery module 204 can be replaced conveniently with a new battery module and thereby making it unnecessary to replace the whole first temperature-measuring unit 20.

The power-monitoring module 205 is configured to measure the power level of the battery module 204, and send a measured value of the power level to the micro-controller module 202 for processing before it is sent to the control unit 40 by a data-transmitting module 203. The control unit 40 receives the measured value of the power level from the first temperature-measuring unit 20 and makes a comparison between each power level value and a fourth pre-determined threshold Q4. In case that the value of the power level is smaller than the fourth threshold Q4, the control unit 40 will send out a third warning message. As such, the user can readily know that the battery module 204 for a certain first temperature-measuring unit 20 would need to be replaced, rather than perform frequent manual tests.

As described earlier, the terminal device 50 of the temperature-monitoring system 100 is used to display information from the control unit 40. In particular, the terminal device 50 may be configured to receive various values of temperatures Tl, T2, T3 and/or the first, second and the third warning messages from the control unit 40, and display at least some of the temperature values and/or the warning messages. Preferably, the terminal device 50 may be a mobile

telecommunication device, such as a cell phone, or the like. As such, the control unit 40 can transmit relevant signals of temperature and/or warning directly to such mobile telecommunication devices by wireless telecommunication to facilitate a user to check the required real-time information anywhere. Of course, the terminal device 50 may also be a computer monitor, such as a computer monitor in a control center.

Fig. 8 illustrates a composition block diagram of the temperature-monitoring system according to the second embodiment of the present invention. The temperature-monitoring system 200 comprises a plurality of the first temperature-measuring units. Although only two of the first temperature-measuring units, i.e. 20-1 and 20-2, for example, are shown in fig. 8, it should be understood that the temperature-monitoring system 200 may comprise ten, or one hundred, or even more of the first temperature-measuring units, depending on the number of the points the

temperatures of which need to be measured. Preferably, at least part or all of the first temperature- measuring units 20-1, 20-2 have a respective unique identification no. (ID no.) D2-1 or D2-2, and this would facilitate a user to figure out the particular point that corresponds to one of the first temperature-measuring units.

The first temperature-measuring unit of the temperature-monitoring system 200 may comprise similar modules and functions as the first temperature-measuring unit of the temperature- monitoring system 100, which is described in an aforementioned embodiment. What is different is that the data- transmitting module 203 will also transmit the ID nos. D2-land D2-2 that correspond respectively to the surface temperatures T2-1 and T2-2 together with the surface temperatures T2-1 and T2-2.

The temperature-monitoring system 200 may further comprise a plurality of terminal devices 50-1, 50-2 and 50-3, etc. Although only three of them are exemplified in fig. 8, such terminal devices can be positioned at different locations based on the actual needs. As a result, the control unit can send the temperature and/or warning messages respectively to these terminal devices such that the user can learn the information in a timely manner.

Other parts of the temperature-monitoring system 200 are identical to those of the temperature-monitoring system 100, and therefore will not be further described.

It should be understood that the above embodiments are just for describing, rather than limiting the present invention. A person of ordinary skill in the art would understand that various modifications and alterations may be made without departing from the spirit of the present invention, and such modifications and alterations would be covered by the scope of the present invention and the appended claims. The scope of the present invention would be defined by the appended claims. Furthermore, any reference numbers included in the claims would not be construed as limiting the scope of the present invention. The verb "comprise" and any variations thereof would not exclude any other elements or steps, although they are not specified in the claims. Indefinite article "a" or "an" that is used before "element" or "step" would not exclude that more than one such elements or steps might exist.

Claims

WHAT IS CLAIMED IS:

1. A temperature-monitoring system for monitoring a temperature T 1 of a j acketed body, the system comprising:

a first temperature-measuring unit, comprising a first temperature sensor and configured to measure a surface temperature T2 of the jacket and send out the measured value of the surface temperature T2;

a second temperature-measuring unit, comprising a second temperature sensor and configured to measure an environment temperature T3 of a space where the jacket is located and send out the measured value of the environment temperature T3;

a control unit, configured to receive the measured value of the surface temperature T2 from the first temperature-measuring unit and the measured value of the environment temperature T3 from the second temperature-measuring unit, and determine a value of the temperature Tl of the body based on the measured value of the surface temperature T2 and the measured value of the environment temperature T3.

2. The temperature-monitoring system according to claim 1, wherein the control unit comprises a lookup table, and the lookup table contains information of a specific value of the temperature Tl corresponding to a certain value of the surface temperature T2 under a certain range of the environment temperature T3.

3. The temperature-monitoring system according to claim 2, wherein the lookup table comprises at least three groups of temperature values, each group includes multiple values of the surface temperature T2 and multiple values of the temperature Tl, each value of the temperature Tl corresponds to one value of the surface temperature T2, the body temperatures Tl and the surface temperatures T2 contained in each group correspond to the same range of the environment temperature T3, but a different group corresponds to a different range of the environment temperature T3.

4. The temperature-monitoring system according to claim 3 , wherein the lookup table comprises three groups of temperature values, the first group of temperature values corresponds to an environment temperature T3 that is greater than a first value Ml, the second group of temperature values corresponds to an environment temperature T3 that is smaller than a second value M2, and the third group of temperature values corresponds to an environment temperature T3 that is between the first value Ml and the second value M2, and the first value Ml is greater than the second value M2.

5. The temperature-monitoring system according to claim 1, wherein the control unit is further configured to make a comparison between the value of the body temperature Tl and a first predetermined threshold Ql, and send out a first warning message if the value of the body temperature Tl is greater than the first pre-determined threshold Ql .

6. The temperature-monitoring system according to claim 5, wherein the control unit comprises a time module configured to count a duration of time that the value of the surface temperature T2 is consecutively greater than a second pre-determined threshold Q2.

7. The temperature-monitoring system according to claim 6, wherein the first pre-determined threshold Ql is greater than the second pre-determined threshold Q2.

8. The temperature-monitoring system according to claim 6, wherein the control unit is further configured to send out a second warning message if the duration of time is greater than a third pre- determined threshold Q3.

9. The temperature-monitoring system according to claim 1, wherein the system comprises a plurality of first temperature-measuring units, and each of the first temperature-measuring units has a unique identification number and is configured to send out the measured value of the surface temperature T2 together with its identification number.

10. The temperature-monitoring system according to claim 5 or 8, wherein the system further comprises at least one terminal device, the terminal device is configured to receive the first and/or the second warning message from the control unit and display the first and/or the second warning message.

11. The temperature-monitoring system according to claim 1 or 9, wherein the first temperature- measuring unit is configured to transmit the measured value of the surface temperature T2 to the control unit through a wireless channel.

12. The temperature-monitoring system according to claim 1, wherein the first temperature- measuring unit comprises a battery module configured to supply electrical power to other elements included in the first temperature-measuring unit, and the battery module is assembled with said other elements of the first temperature-measuring unit in a detachable way; the first temperature-measuring unit further comprises a power-monitoring module configured to monitor the power level of the battery module, and send out a measured value of the power level; and

the control unit is further configured to receive the measured value of the power level from the first temperature-measuring unit, and send out a third warning message when the value of the power level is smaller than a pre-determined threshold Q4.

13. The temperature-monitoring system according to claim 1 , wherein the body comprises at least one cable conductor, the jacket comprises a protection insulation layer.