The ultimate guide to choosing fiber optic temperature sensors

Senzor temperature od optičkih vlakana, Inteligentni sustav nadzora, Distribuirani proizvođač optičkih vlakana u Kini

Fiber optic temperature sensors have significant importance and broad application prospects in modern measurement fields. The unique value of fiber optic sensing technology in meeting the temperature measurement needs of special environments such as high electromagnetic and corrosive environments.

1. Overview of Fiber Optic Temperature Sensor
2. Working principle of fiber optic temperature sensor
3. Characteristics of Fiber Optic Temperature Sensor
4. Application of Fiber Optic Temperature Sensor

 

Introduction to Fiber Optic Temperature Sensor

 

Senzor temperature od optičkih vlakana is a new type of sensor developed in the 1970s. In scientific research and production, there are numerous demands for temperature measurement. Traditional temperature sensors include thermocouples, termistorski temperaturni senzori, termistorski temperaturni senzori, semiconductor temperature sensors, itd. Međutim, fiber optic temperature sensors have obvious advantages compared to traditional sensors, such as high sensitivity, small size, mala težina, easy bending, nema elektromagnetskih smetnji, nema elektromagnetskih smetnji, and good corrosion resistance. They are particularly suitable for temperature detection in harsh environments such as flammable, eksploziv, narrow spaces, and corrosive gases, liquids, and radiation pollution. From the perspective of modulation mechanism, it can be divided into phase modulation, amplitude modulation, and polarization modulation; According to the working principle, it can be divided into functional and transmission types. In functional temperature sensors, optical fibers serve as both sensors and carriers of optical signals, while in transmission type temperature sensors, optical fibers only transmit optical signals. Although the light transmission type has slightly lower sensitivity, it has high reliability, and most practical sensors belong to this type. At present, the main fiber optic temperature sensors include distributed fiber optic temperature sensors, fiber optic grating temperature sensors, fiber optic fluorescence temperature sensors, interferometric fiber optic temperature sensors, itd

How does a fiber optic temperature sensor work

 

1、Working principle of fluorescent fiber optic temperature sensor

 

Fluorescent fiber optic temperature sensor is a sensor that uses fluorescent materials to undergo changes in fluorescence intensity or wavelength under temperature changes, and transmits signals through optical fibers to achieve temperature detection. It mainly consists of a light source, optical fibers, fluorescent materials, and a spectral analyzer. The light source generates excitation light of a certain wavelength, which is transmitted to the fluorescent material through optical fibers. Fluorescent materials are materials that can absorb light of a certain wavelength and emit longer wavelength light. After absorbing excitation light, fluorescent materials emit fluorescent signals with specific wavelengths, which are transmitted back to the spectrometer for detection through optical fibers. When the temperature changes, the fluorescence characteristics of the fluorescent material will change, which may be a change in fluorescence intensity or a shift in fluorescence wavelength. The temperature value can be determined by measuring the intensity or wavelength of the fluorescence signal. Osim toga, there are two main temperature measurement methods based on fluorescence intensity ratio and fluorescence lifetime. Npr, in some measurement systems, fluorescent substances can be uniformly coated on the surface of the object being measured, and excitation light can be transmitted through one optical fiber to make the substance emit fluorescence, while another optical fiber can receive the fluorescence. If the object being measured is not suitable for applying fluorescent substances (such as when measuring liquids), a fiber optic probe can be used to spray fluorescent powder, or a fiber optic temperature probe can be formed by mixing fluorescent powder with fiber optic material to accurately measure the surface temperature of the object.

2、The working principle of fiber Bragg grating sensor

 

Fiber Bragg Grating Temperature Sensor utilizes the photosensitivity of fiber optic materials to measure temperature using a spatial phase grating formed in the fiber core. Specifically, npr, fiber Bragg gratings (FBGs) are based on the photosensitivity of optical fibers and use ultraviolet light irradiation to cause periodic refractive index changes in the fiber core. When the external temperature changes, both the period and refractive index of the Bragg grating will change, resulting in a drift of the Bragg wavelength λ B. Temperature can be measured by measuring the Bragg reflection wavelength of the Bragg grating. This type of sensor belongs to wavelength modulation type. Fiber Bragg Grating can be divided into single fiber Bragg Grating and multi fiber Bragg Grating. Single fiber Bragg Grating is similar to the method of encapsulating single fiber Bragg Grating with polymer materials, which utilizes the different responses of organic matter to temperature and stress to increase the sensitivity of fiber Bragg Grating to temperature or stress, and overcomes cross sensitivity effects; There are also methods of writing gratings at the connection between two types of optical fibers with different refractive indices and temperature sensitivities, or different temperature response sensitivities and doping material concentrations, and using different refractive indices and temperature sensitivities to distinguish measurements. Međutim, these methods have problems such as complex demodulation, high loss, easy breakage at the fusion joint, and small measurement range. Multi fiber Bragg gratings, such as dual period fiber Bragg gratings, can ensure measurement position and improve measurement accuracy, but the grating intensity is low and signal demodulation is difficult; The double FBG overlapping writing method has high accuracy, but grating writing is difficult and signal demodulation is also complex; Fiber Bragg Grating/F-P cavity integrated composite sensor has good temperature stability, small size, and high measurement accuracy, with an accuracy of up to 20 × 10-6 i 1 °C. Međutim, adjusting the cavity length of F-P is difficult and signal demodulation is complex.

3、The working principle of distributed fiber optic sensors

Distributed fiber optic sensors were first proposed by the University of Southampton in the UK in 1981. The reflected light of laser in fiber optic transmission mainly includes three parts: Rayleigh scattering, Raman scattering, and Brillouin scattering. Distributed fiber optic temperature sensors are mainly based on Raman scattering effect and optical time domain reflectometry (OTDR) technology to achieve continuous distributed measurement. The intensity of Raman scattering signal is correlated with the temperature at the location of the point. In a distributed fiber optic temperature sensing system, when a strong pulsed laser signal is transmitted in the fiber optic cable, each point in the fiber optic cable will produce extremely weak backscatter on the laser signal. By detecting the intensity of the scattered light signal at each point, the temperature information of that point can be obtained, and then the temperature distribution on the entire fiber optic cable can be obtained. The time-domain and frequency-domain systems based on Brillouin scattering are also a hot research topic in the field of fiber optic sensors.

 

Characteristics of Fiber Optic Temperature Sensor

 

1、Advantages of Fluorescent Fiber Optic Temperature Sensor

1. High sensitivity

Fluorescence fiber optic temperature measurement technology uses changes in fluorescence afterglow to measure temperature, which can detect small temperature changes. Npr, in some environments that require precise monitoring of temperature changes, even extremely subtle temperature fluctuations can be sensitively captured by fluorescent fiber optic temperature measurement systems, with a sensitivity of up to 0.1 ℃ or even higher precision levels. This characteristic makes it widely used in many fields that require high-precision temperature measurement, such as in the heat dissipation monitoring of electronic chips. Small temperature changes may affect the performance and lifespan of the chip. Fluorescent fiber temperature measurement can provide timely and accurate temperature information, which helps optimize heat dissipation design, improve chip stability and reliability.

2. Not affected by electromagnetic interference

Fluorescence fiber optic temperature measurement is based on temperature measurement using fluorescent fibers. Due to the physical properties of optical fibers, they are not affected by electromagnetic interference in the surrounding environment. In modern industrial environments, there are a large number of electromagnetic devices such as motors, transformers, itd. The electromagnetic fields generated by these devices may interfere with traditional temperature measurement equipment, resulting in inaccurate measurement results. Međutim, fluorescence fiber optic temperature measurement technology can still operate stably in this complex electromagnetic environment. Npr, in the power system, there is a strong electromagnetic field around the high-voltage equipment in the substation. Fluorescent fiber temperature measurement can accurately measure the temperature of the equipment, such as the hot spot temperature of transformers, providing reliable temperature monitoring data for the safe operation of power equipment and avoiding power safety accidents caused by measurement errors due to electromagnetic interference.

3. Diversity and flexibility of measurement points

By changing the number and position of fluorescent probes in the optical fiber, multi-point or distributed temperature measurement can be easily achieved. This flexibility greatly increases the applicability of the system. Npr, in large power transformers, multiple fluorescent probes can be installed at different winding positions to comprehensively monitor the temperature distribution at different locations inside the transformer. In temperature monitoring of switchgear, optical fibers can be laid along the hot and critical parts of the switchgear and multiple probes can be set up to have a comprehensive understanding of the temperature status of the overall structure, timely detect possible temperature anomalies, and provide a basis for the safe maintenance of power equipment.

4、 Wide measurement range

Fluorescent fiber optic temperature measurement technology can adapt to a wide temperature measurement range. In the important equipment hotspot temperature measurement in many fields such as power, military, petrochemical, rail transit, and new energy, the operating temperature range of these devices may be wide, and fluorescent fiber optic temperature measurement can be competent. Npr, some special equipment in the military industry may work in extremely cold or high temperature environments, and fluorescent fiber optic temperature measurement systems can accurately measure the temperature of the equipment at different environmental temperatures; In the thermal management of batteries in the field of new energy, the temperature range of batteries during charging and discharging is large. Fluorescent fiber temperature measurement can accurately monitor the temperature throughout the process, ensuring the safety and performance of batteries.

5、 High voltage resistance

Fluorescent fiber optic temperature measurement products have high voltage resistance, with a voltage resistance greater than 100KV. This allows it to directly measure temperature in high voltage environments. Npr, in the temperature monitoring of equipment in ultra-high voltage substations, when facing high voltage environments exceeding 100KV, the end of the fluorescent fiber can make zero distance contact with the equipment for temperature measurement without being affected by high voltage, ensuring the normal operation of measurement work and providing important temperature data support for the safe operation of power equipment.

6、 Easy probe installation

The probe installation of the fluorescent fiber optic temperature measurement system is relatively simple. Npr, in temperature monitoring of transformers, the probe can directly contact the transformer coil without the need for complex isolation operations. This simple installation method not only saves installation time and cost, but also improves installation accuracy and reliability, ensuring the effectiveness of temperature measurement. U isto vrijeme, in the narrow space inside some complex equipment, this simple installation probe can also be conveniently arranged without interfering with the normal operation of the equipment.

7、 Easy maintenance and high safety

Fiber optic cables can come into contact with iron cores, channel steel, busbars, itd. during use, making wiring convenient. When conducting a pressure test, there is no need to disassemble the plug of the temperature controller sensor. Osim toga, when the optical cable is damaged, it will not affect the insulation of the transformer, which greatly reduces the difficulty and workload of maintenance. Npr, in the maintenance process of transformers in the power system, compared with traditional temperature measurement methods, fluorescent fiber optic temperature measurement systems do not require frequent disassembly and inspection of sensors, reducing the impact of maintenance work on equipment operation and improving the safety of equipment operation. In flammable and explosive places such as petrochemicals, the characteristics of low maintenance requirements and high safety are even more crucial, which can effectively avoid safety accidents caused by maintenance operations.

8、 Corrosion resistant and suitable for special environments

Fiber optic materials have low sensitivity to electronic activity and can be widely used in situations where metal temperature sensors cannot be applied, such as strong magnetic fields and strong electric fields. And compared with conventional heat conduction temperature sensors, it has the advantage of corrosion resistance, especially suitable for temperature measurement in small micro environments such as micro pipelines and narrow slits that are not easily accessible. Npr, in the vicinity of some corrosive media transmission micro pipelines in chemical production, or in narrow spaces inside electronic devices with strong magnetic fields, fluorescence fiber optic temperature measurement can work stably and accurately measure temperature, while traditional metal sensors may not work properly due to corrosion or interference from strong magnetic fields.

2、Characteristics of Fiber Bragg Grating Temperature Sensor

Strong anti-interference ability: Generally, the frequency of electromagnetic radiation is much lower than that of light waves, and the optical signals transmitted in optical fibers are not affected by electromagnetic interference. This allows fiber Bragg grating temperature sensors to work normally in complex electromagnetic environments, such as temperature detection in densely populated areas of electrical engineering equipment.
Corrosion resistance and stable chemical properties: Due to the excellent chemical stability of quartz, the material used to make optical fibers, fiber Bragg grating temperature sensors are suitable for use in harsh environments such as temperature monitoring in chemical production workshops and offshore oil platforms.
Small size, mala težina, and flexible geometric shape: This feature allows it to be used in places with limited installation space, such as temperature measurement in narrow spaces inside aerospace equipment, and can be adjusted in shape according to different installation requirements.
Good electrical insulation performance, safe and reliable: Optical fibers themselves are composed of dielectric materials and do not require power drive, making them suitable for use in flammable and explosive oil, gas, and chemical production (such as temperature monitoring in refineries, natural gas transportation pipelines, and other equipment).
Large transmission capacity and multi-point distributed measurement: It can achieve temperature measurement at multiple points, and the measurement results can be transmitted through optical fibers to meet the temperature monitoring needs of large areas or multiple components, such as temperature distribution monitoring of large building structures; U isto vrijeme, the transmission loss is relatively small, which enables remote monitoring over long distances.

 

3、Characteristics of Distributed Fiber Optic Temperature Sensor

 

1、 High sensitivity

Compared with traditional temperature sensors, it can sense small temperature changes. Npr, in some high-precision laboratory environment monitoring or high-precision industrial production process temperature monitoring, extremely weak temperature fluctuations can be accurately captured. This is because its working principle is often based on the subtle relationship between light signals and temperature, such as the intensity of scattered light in Raman scattering, which is related to temperature. Even small changes in temperature can cause significant changes in the Raman scattering light signal, which can be recognized by the detection system and obtain the accurate change in temperature. Application example: Temperature monitoring during the reaction process of some hazardous chemicals in the chemical production process. When a chemical reaction occurs, the extremely small temperature changes caused by the thermal effect of the reaction can be detected by distributed fiber optic temperature sensors to accurately control the reaction process and avoid danger caused by uncontrolled temperature changes.

2、 Strong ability to resist electromagnetic interference

The unique performance optical fiber itself is composed of quartz material, completely electrically insulated, so the distributed optical fiber temperature sensor is completely unaffected by external electromagnetic environment interference during measurement. In strong electromagnetic field environments, such as near large power equipment or inside high-voltage substations, the sensor can operate normally. This has unique advantages in scenarios such as temperature monitoring of electrical equipment in power systems and temperature monitoring of large motors. Unlike traditional electrical temperature sensors, which may experience measurement distortion or malfunctions due to strong electromagnetic interference, it ensures measurement stability and accuracy. Compared with traditional thermocouples or resistance temperature sensors, when used near strong electromagnetic interference sources (such as large alternating electromagnetic field equipment), their measurement signals will be affected by electromagnetic interference, resulting in inaccurate measurement results. Međutim, distributed fiber optic temperature sensors do not have such problems at all, and can work stably even in extreme environments such as lightning and magnetic fields.

3、 Capable of long-distance multi-point detection

The detection form and other characteristics can achieve temperature field distribution detection along a continuous space of several tens of kilometers along the optical fiber, and the temperature of multiple points on this fiber can be monitored simultaneously. Not only can it detect long distances, but it can also set up numerous monitoring points on a single fiber optic cable. This characteristic is particularly prominent in places where oil and gas pipelines, mine tunnels, and other long distances require temperature monitoring at multiple different locations. It can simultaneously monitor temperature changes at different locations on a longer pipeline segment. Compared with traditional single point measurement temperature sensors, such as traditional glass liquid thermometers, which can only measure the temperature of one point at a time, distributed fiber optic temperature sensors achieve long-distance integration of multiple measurement points, saving manpower and material resources, and reducing the accumulation of errors caused by multiple point arrangements. Npr, in temperature monitoring of long-distance oil pipelines across regions, reducing the complexity of a large number of intermediate transfer equipment and repeated point deployment can achieve seamless continuous multi point temperature monitoring on pipelines spanning tens or even hundreds of kilometers.

4、 Significant networked sensing characteristics

Special layout and working method arrange sensing fibers or fiber optic sensor circuits along the distribution of the applied field (kao što je temperatura, pressure, naprezanje, itd.), which can measure and monitor the spatial distribution and temporal information on the circuit field. It can be understood as implementing comprehensive monitoring of temperature distribution within an area or space, similar to building a network monitoring system. Npr, laying fiber optic sensing circuits on large building structures or within a certain range of sites to achieve comprehensive control and data collection of temperature changes in the entire area. Widely used in fire monitoring scenarios in urban lifeline systems, it can achieve distributed temperature detection in large warehouse clusters, high-rise office buildings, or large-scale commercial complexes. It can timely locate the specific location of temperature anomalies (potential fire areas), detect abnormal temperature increases in extremely small areas in the early stages of fire hazards, and accurately locate within a certain spatial range.

5、 Other characteristics

Continuous, distributed, and real-time measurement can perform continuous and distributed real-time temperature monitoring at various points within a certain spatial range or along a fiber optic path. Npr, in a tunnel, the optical fibers laid along the tunnel wall can provide real-time feedback on the temperature situation of each section. It is not a discrete and intermittent measurement of a few temperature values, but an uninterrupted and continuous monitoring of the temperature throughout the entire length of the optical fiber and at each point. Intrinsic safety and remote monitoring Intrinsic safety is due to the fact that optical fibers do not involve circuits, and there is no possibility of danger caused by electric sparks. When monitoring the environmental temperature in special flammable and explosive hazardous areas such as oil storage tanks and explosives depots, it can completely avoid the risk of explosion caused by short circuits in electrical sensors. U isto vrijeme, it has remote monitoring capabilities, as long as the data is transmitted to a remote monitoring center through signal transmission lines (optical fibers themselves or accompanying transmission equipment), it can easily obtain real-time temperature data from a distance. In terms of high cost-effectiveness, although the initial construction may incur relatively high costs for laying fiber optic lines, in the long run, due to the ability to achieve long-distance, large-scale, and high-density monitoring, the average cost per monitoring point is relatively low. Npr, in large industrial plants, if traditional temperature sensors are used to build a monitoring network, the cost of each independent sensor and wiring at each point is much higher than the long-term overall cost of using distributed fiber optic temperature sensors. Easy installation and long lifespan. When installing, simply lay the fiber optic cable according to the designed route, without complex circuit connections or heavy equipment installation issues. Osim toga, due to the material properties of optical fibers, such as good chemical stability and mechanical strength, they can operate for a long time in harsh natural or industrial environments, resulting in a longer lifespan. In some environmental monitoring projects in remote areas, once installed, they can work stably and reliably for a long time.

4、Application of Fiber Optic Temperature Sensor

 

1、Practical Application of Fluorescent Fiber Optic Temperature Sensor

 

1. Application of Fluorescent Fiber Optic Temperature Sensor in Switchgear Contact

Fluorescent fiber optic temperature sensors play a crucial role in monitoring the contacts of switchgear.

Switchgear is a critical equipment in the power system, and its operational status directly affects the safety and stability of the power grid. If the temperature at the contacts inside the switchgear is too high, it can cause serious problems such as aging of insulation materials and poor contact, which may lead to accidents. Fluorescent fiber optic temperature sensors can effectively monitor the temperature of switchgear contacts.

Firstly, in principle, a fluorescent fiber optic temperature sensor is a temperature sensor based on fiber optic technology and fluorescence principle. It utilizes the dependence of the fluorescence characteristics of specific materials on temperature and achieves temperature measurement by measuring changes in fluorescence lifetime. This measurement method has high accuracy.

In actual installation, fiber optic fluorescent sensors will be installed at key locations such as contacts inside the switchgear. Due to the spatial resolution capability of optical fibers, it is possible to achieve simultaneous monitoring of multiple temperature points inside the switchgear. Taking the switchgear in a certain power system as an example, this sensor can measure the temperature status of each contact in real time. Npr, in some large substations, many switchgear contacts are fully covered by the monitoring of this sensor.

Sljedeći, the sensor will calculate the real-time temperature of each monitoring point by measuring the changes in fluorescence signals. Then transmit these temperature data to the monitoring center to achieve remote real-time monitoring. Once the temperature of a contact exceeds the preset threshold, the monitoring center can receive an alarm in a timely manner, reminding the operation and maintenance personnel to conduct inspection and maintenance.

Sensors themselves also have many advantages that are suitable for this application scenario. Its electrical insulation ensures safety in high-voltage switchgear environments and can withstand high voltage while working normally; Strong anti-interference ability, not affected by the electromagnetic field inside the switchgear, ensuring accurate and reliable measurement results; Osim toga, it is small in size and light in weight, making it easy to install and integrate in relatively small spaces such as switch cabinet contacts. It does not require too much installation space or additional reinforcement measures, making temperature monitoring of the switch cabinet simple and efficient. It comprehensively grasps the temperature situation of the contacts to prevent faults, and improves the safety and reliability of switch cabinet operation.

2. Application of Fluorescent Fiber Optic Temperature Sensor in Transformer Winding

In transformers, the winding is one of the key components and is extremely important for the normal operation of the transformer. Fiber optic fluorescence sensors are of great significance for monitoring the temperature of transformer windings.

As the core equipment of the power system, the temperature during the operation of transformers has a direct impact on the transmission and distribution of electrical energy. The winding generates heat during long-term operation, and high temperature is one of the main factors causing accelerated aging of transformer insulation materials. Stoga, monitoring the temperature of the winding has become a necessary means to ensure the normal operation of transformers.

The application of fluorescent fiber optic temperature sensors in transformer windings is similar to that in switchgear, but there are also special requirements. The internal structure of transformers is complex, and when installing sensors, it is necessary to arrange them reasonably based on the characteristics of the internal structure, such as avoiding complex oil circuits and other structures. The internal temperature distribution is uneven, and the distributed measurement characteristics of the fiber optic fluorescence sensor are utilized here. It can achieve multi-point and distributed measurement along the length of the fiber, and sensors can be arranged at multiple positions of the winding to comprehensively grasp the temperature distribution of the winding. Osim toga, the operating environment of transformers is harsh, and sensors need to have good high temperature and oil resistance performance in order to work stably in the oil immersed environment around the winding for a long time.

Specifically, sensors will be installed at the transformer winding location according to the settings to monitor temperature changes in the winding. Then, using the same method of measuring changes in fluorescence signals to obtain temperature data, real-time temperature data is transmitted for analysis or combined with other monitoring data such as oil and gas analysis, partial discharge, itd. for comprehensive diagnosis. Npr, when an abnormal temperature rise is detected at a certain point of the winding, the system can combine other data such as partial discharge to determine whether it is a simple temperature problem or if there are other deeper fault hazards. Once the temperature exceeds the set threshold, an alarm will be promptly triggered to remind the operation and maintenance personnel to take measures, such as adjusting the load, conducting maintenance, itd., to avoid serious accidents such as insulation damage caused by winding overheating, which will affect the service life of the transformer, ensure the normal operation of the transformer, and extend its service life.

3. Application of Fluorescent Fiber Optic Temperature Sensor in Medical Human Intervention

In the medical field, fluorescent fiber optic temperature sensors have shown unique advantages for human body temperature measurement through interventional methods.

Human body temperature is an important physiological parameter in the biomedical field, and accurate temperature measurement can provide doctors with important information about physiological status, assisting in diagnosis and treatment processes. Especially in some special medical scenarios, such as thermal therapy, traditional sensors cannot meet the measurement needs.

In terms of thermal therapy, such as microwave or radiofrequency thermal therapy, real-time non-destructive monitoring of the temperature of human cancerous tissue is required because cancer cells have less blood flow, slower heat dissipation, and are more sensitive to heat than normal cells. When the human tissue is heated to 42-45 ℃ during thermal therapy, cancer cells can be killed while normal tissue is not significantly damaged. Međutim, normal cells can also be severely damaged beyond 45 °C. This requires high-precision temperature measurement during thermal therapy, and the measurement method should avoid electromagnetic interference. Traditional medical sensors such as thermocouple temperature sensors, termistorski temperaturni senzori, infrared thermal radiation temperature sensors, itd. cannot meet the requirements for use. Their sensing elements are mostly conductors, which can cause problems such as Ohmic heat or skin effect, leading to an increase in their own temperature or measurement error, affecting the treatment effect.

The temperature sensing probe of the fluorescent fiber optic temperature sensor is based on the material properties of rare earth fluorescent substances. When excited by ultraviolet radiation, it can emit fluorescence with temperature related characteristics and its afterglow. Its biggest advantage is that the temperature of the target being measured depends only on the time constant of the fluorescent material, and is not affected by other variables such as light source intensity, transmission efficiency, and coupling degree. This type of sensor uses light to measure temperature, and probes made of glass and polymer are non-conductive and have good electrical insulation properties. It is not affected by electromagnetic field interference, has high measurement accuracy, short temperature measurement cycle, sensitive response, good fiber flexibility, and small temperature sensing probe volume (up to 0.5mm at the minimum), suitable for contact type surface or in vivo temperature measurement. The outer layer of the sensor can be customized with a silicon fiber sheath for easy disinfection, high temperature resistance, otpornost na koroziju, explosion-proof and flame-retardant properties, and easy and flexible operation. It can also be directly connected to medical equipment or computers for multi-point monitoring and centralized temperature display. Npr, in the integrated thermal therapy equipment, a fluorescent fiber temperature sensor can be connected to it. When performing tumor thermal therapy on cancer patients, the temperature of the cancerous site can be accurately monitored without affecting normal tissues, ensuring the safety and effectiveness of thermal therapy.

Osim toga, in some scenarios where precise monitoring of human body temperature is required, such as surgical procedures or rehabilitation centers, fluorescent fiber optic temperature sensors can also monitor patient temperature changes with high precision and fast response, thereby helping doctors control the temperature of the surgical environment to ensure smooth surgery, or assisting doctors in evaluating the patient’s recovery status in rehabilitation centers.

4. Application of Fluorescent Fiber Optic Temperature Sensor in Electromagnetic Interference

Fluorescent fiber optic temperature sensors exhibit excellent performance in electromagnetic interference environments.

There is strong electromagnetic interference in many industrial, medical, or scientific research scenarios, and traditional temperature measurement methods are susceptible to these interferences, resulting in inaccurate measurement results. Electromagnetic interference is ubiquitous, such as the presence of strong magnetic and electric fields around equipment in some power transmission and transformation systems, high magnetic field environments in the superconducting magnet area of medical magnetic resonance imaging (MRI), and scientific experimental environments that require the use of electromagnetic equipment.

Based on the principle of fiber optic fluorescence sensors, it utilizes the temperature dependence of the fluorescence characteristics of specific materials to measure temperature, relying on the measurement of changes in fluorescence lifetime to achieve temperature measurement. In specific operations, the transmission of optical signals in the sensor is the core link. And optical fibers have good electrical insulation, which is an inherent characteristic of their materials. As an electrical insulator, optical fibers can work in high voltage and strong electromagnetic interference environments, ensuring the safety and reliability of measurements. The optical signal in the fluorescent fiber optic temperature sensor is not affected by electromagnetic interference, which enables it to accurately measure temperature even in strong electromagnetic interference scenarios.

Npr, in the monitoring of switchgear and transformers in the field of power, compared with traditional temperature sensors, such as in switchgear in high voltage environments, traditional temperature sensors may have inaccurate readings or unstable measurements due to electromagnetic interference. Međutim, fluorescent fiber temperature sensors can stably and accurately monitor the temperature of switchgear contacts, transformer windings, and other parts, avoiding difficulties in equipment maintenance or potential accidents caused by temperature misjudgment due to electromagnetic interference. In the medical field, npr, in magnetic resonance imaging (MRI) Tehnologija, superconducting magnets need to be cooled to extremely low temperatures and there is a strong magnetic field nearby. The monitoring requirements for the temperature of the cooling system are relatively high. If traditional electronic temperature sensors are used, they will inevitably be affected by magnetic field interference or damage, while fiber optic sensors can work normally in such an environment to ensure that the magnet is at the correct temperature.

5. Application of Fluorescent Fiber Optic Temperature Sensor in Adverse Environments

Fluorescent fiber optic temperature sensors can adapt well to harsh environments.

The temperature measurement in various harsh environments has prompted the application of fluorescent fiber optic temperature sensors. Firstly, from some industrial scenarios, such as nuclear power, petrokemija, metallurgy, itd., these places are often located in high-temperature, high-pressure, and highly corrosive environments. In high temperature environments, many traditional temperature sensor materials may undergo performance changes or even damage, npr, some sensors made of metal materials may deform at high temperatures, resulting in inaccurate measurements. Međutim, the high temperature resistance of the fluorescent fiber optic temperature sensor itself and the structural stability based on the fiber optic can adapt to such high temperature environments and accurately measure temperature. In high-voltage environments, its electrical insulation ensures safety while accurately measuring without being affected by high voltage, such as temperature measurement of internal switches and other parts of switchgear (high-voltage electrical equipment) in power systems.

Furthermore, in highly corrosive environments, optical fibers themselves are made of special materials that have certain resistance to many corrosive substances. Taking the petrochemical industry as an example, there are many corrosive chemical gases or substances in the surrounding air or working material environment, and this type of sensor can work normally for a long time in this environment.

Osim toga, in some complex outdoor environments, such as outdoor power equipment or communication base stations. Due to the small size and light weight of fluorescent fiber temperature sensors, they are easy to install and do not require significant modifications regardless of the complex equipment structure they are installed on. Osim toga, it has the characteristics of distributed measurement, which can better monitor the temperature of multiple measurement points or devices in a large area, such as comprehensively grasping the temperature situation of numerous transformers and other equipment in the outdoor area of a large substation. In some small spaces or environments with special shapes, the flexible and bendable characteristics of optical fibers can enable sensors to adapt to these environmental layouts, enabling temperature measurement of some special shaped devices or small cavities, such as temperature measurement inside pipelines, itd. It is capable of temperature monitoring in small and harsh environments.

2、Practical Application of Fiber Bragg Grating Temperature Sensor

 

Fiber Bragg grating temperature sensors have wide applications in multi-point fiber optic temperature measurement.

1、 Multi location temperature measurement in the power system

Connection between switchgear and cables
Fiber Bragg grating temperature sensors are highly suitable for temperature monitoring and fire alarm at high-voltage power switchgear and high-voltage cable joints in power plants, substations, and other places due to their excellent insulation, otpornost na visoki napon, anti creepage, otpornost na koroziju, strong lightning resistance, and resistance to strong electromagnetic interference. Due to poor contact and other reasons, cable joints and other parts in these places are prone to local overheating, and ordinary temperature sensors may not work accurately due to electromagnetic interference or harsh environments. Fiber Bragg grating temperature sensors can accurately monitor the temperature of multiple such connection points, timely detect overheating hazards, and avoid power failures or fires caused by overheating.
In an environment with a large number of cable installations such as cable tunnels, traditional digital sensors can only monitor the temperature of important parts such as cable joints, while distributed fiber optic temperature monitoring systems and fiber optic grating temperature measurement systems can achieve temperature monitoring throughout the entire length of cables. Fiber Bragg grating temperature sensors can be attached to the surface of cables or cable joints at multiple points to monitor the real-time temperature of cables, detect possible hotspots and abnormal behavior points (such as rapid and chronic heating points), and effectively prevent cable faults. By combining real-time current, various operating states can be simulated, and the cable core temperature can be calculated to calculate the dynamic current carrying capacity and determine the temperature and location information of the bottleneck points that limit the cable current carrying capacity, providing scientific basis for power dispatch.
Multiple key components of power generation equipment
If fiber optic grating temperature sensors are used for multi-point monitoring in different generator sets in thermal power plants or hydropower plants, such as the wet steam area inside the steam turbine and the synchronous phase-shifting camera rotor, the distribution of temperature and humidity fields inside the steam turbine can be dynamically determined. Sensors can be installed and arranged with multiple probes according to the structural characteristics of the device and the thermal critical areas that need to be monitored, accurately obtaining temperature information at different locations. Then, by comprehensively analyzing the temperature data collected from multiple locations, it can help optimize the operating parameters of power generation equipment, improve power generation efficiency, and prevent faults from occurring.
Integrated monitoring of multiple devices within the substation
The substation contains numerous different devices, such as transformers, switchgear, itd. Fiber Bragg grating temperature sensors can be used for multi-point temperature measurement of various main equipment and equipment connection parts in substations. Npr, in key heating areas such as windings and iron cores of large transformers (such as installing 2 sensors per phase for high-voltage windings A, B, and C, 2 sensors per phase for iron cores, 1 sensor per phase for three-phase busbars, i 2 sensors per phase for top and bottom oil temperatures), temperature monitoring of multiple switchgear contact points in the substation is also carried out. By collecting temperature data from multiple points, a temperature condition map of the entire substation can be constructed, enabling comprehensive temperature management and status monitoring of substation equipment.

2、 Multi point temperature measurement in the field of architecture

Temperature monitoring of the overall structure of large buildings
For large buildings such as skyscrapers, bridges, itd., fiber Bragg grating temperature sensors can be buried inside building materials for high-resolution measurement of internal temperature. Sensors can be embedded at key structural locations of buildings, such as beam column connection points, different heights of bridge piers, and different positions inside the beams, to monitor the internal temperature continuously for a long time. Due to factors such as different seasons or temperature differences between day and night, there are differences in temperature inside and outside buildings, as well as temperature changes in structural components in different directions. This multi-point measurement helps to analyze the impact of temperature changes on the overall structural deformation and stress distribution of buildings, thereby providing guarantees for building safety.
In terms of bridges, many foreign countries (such as the United States, the United Kingdom, Japan, itd.) have conducted extensive research on bridge safety monitoring and installed bridge safety monitoring and early warning systems on some major bridges. Fiber Bragg grating temperature sensor is one of the important monitoring sensors, which can monitor key safety indicators such as temperature acceleration, naprezanje, displacement of bridges by installing multiple sensors at different positions on the bridge. Npr, on large-span suspension bridges or sea crossing bridges, fiber optic grating temperature sensors can be installed at multiple points such as the main cable, tower structure, and surface to understand the impact of temperature changes on the entire bridge structure. Temperature changes can cause thermal expansion and contraction, which in turn affect structural stress and other factors. Multi point measurement can more accurately grasp the temperature change law of the bridge and provide data support for its maintenance and safe operation.
Multi point monitoring of thermal pipeline network system
For the thermal pipelines of urban centralized heating systems, fiber optic grating temperature sensors can perform multi-point temperature monitoring at different parts of the pipeline, such as pipeline interfaces, pipeline bends, and locations with different pipe diameters. Due to the heat dissipation and uneven distribution of heat in different locations during the transportation of hot water or steam by thermal pipelines, the temperature of soil and other media around the pipeline can also affect the pipeline itself. By monitoring temperature at multiple points, abnormal heat dissipation points, temperature changes caused by leaks, and temperature fluctuations along the pipeline due to external environmental influences can be detected in a timely manner, and measures can be taken to ensure the safety and normal heating function of the thermal pipeline.

3、 Application in the aerospace field

Temperature monitoring of multiple parts of the aircraft fuselage
In the aerospace industry, the operational safety of aircraft is crucial and is influenced by various factors, among which temperature is a key factor. Fiber Bragg grating temperature sensors can be used to monitor the temperature of multiple key parts of an aircraft, such as different areas of the engine surface (near the combustion chamber, turbine, itd.), different positions of the internal structure of the wing (including wing beams, ribs, itd.), key transmission and bearing parts of the landing gear, and the temperature of multiple parts such as the electronic equipment compartment inside the aircraft. Because during the flight of an aircraft, different parts are affected by external factors such as airflow, solar radiation, itd., and the temperature field distribution is also affected by the heat generated by the operation of various equipment on the aircraft itself. Multiple fiber Bragg grating temperature sensors working together can comprehensively collect temperature data of various important parts of the aircraft to provide a basis for flight safety assessment.

4、 Implementation forms and benefits of multi-point measurement in the field of biomedicine

Example of multi location application in medical facilities
In the hospital setting, especially in some large medical facilities such as MRI equipment, CT scanning equipment rooms, itd., there are relatively high requirements for environmental temperature control. Fiber Bragg grating temperature sensors can be distributed at different locations in the equipment room, such as near the heat dissipation ports around the equipment, in the corners of the room walls, near doors and windows, itd., to achieve accurate measurement of the temperature field distribution inside the room. This helps ensure the temperature stability of the equipment during operation, thereby ensuring that the imaging accuracy and other performance of the equipment are not affected by temperature changes, and the normal service life of the equipment is also guaranteed.
Inside the operating room, it is necessary to have good area control over the entire ambient temperature inside the operating room. Fiber Bragg grating temperature sensors can be installed at multiple points around the operating table, near air conditioning vents, and at the corners of the operating room. This enables accurate zoning measurement of the operating room temperature, and by adjusting air conditioning and other equipment, different functional areas in the operating room can achieve appropriate temperature requirements to ensure smooth surgery and stable physiological status of patients.
Scene of multi-point temperature measurement inside the human body
During the process of cancer hyperthermia, fiber Bragg grating temperature sensors can achieve real-time measurement of tissue temperature at multiple points. Compared to traditional thermometers that are susceptible to electromagnetic radiation interference, fiber optic temperature sensors have advantages. Sensors can be accurately inserted into tumor tissue and its surrounding areas at different positions, while also measuring the temperature of normal tissue and tumor tissue edges, forming multiple temperature measurement points to effectively grasp the tissue heating situation during thermal therapy. Because if the heating temperature of tumor tissue is not sufficient, the therapeutic effect cannot be achieved. If the temperature is too high, it will damage normal tissue. Multi point monitoring can accurately control the temperature distribution during the thermal therapy process. U isto vrijeme, the small size of fiber Bragg grating sensors causes minimal damage to human tissues. Their small size, built-in network security production devices, high temperature resistance, otpornost na koroziju, and high accuracy make it safer and more accurate to provide precise data information about body temperature, local tissue temperature, pressure, and acoustic fields when measuring multi-point temperatures inside the human body.

Practical Application of Fiber Bragg Grating Temperature Sensor in Temperature Measurement of Generator Stator in Hydropower Station

1、 The limitations of traditional stator temperature measurement methods for hydroelectric power station generators
In hydropower stations, temperature monitoring of the generator stator is a key link to ensure the normal operation of the generator. The traditional method of measuring the temperature of the generator stator mainly has the following problems.

The unreliability of using platinum resistance for temperature measurement
For hydroelectric generators, due to long-term exposure to strong magnetic fields and high currents, traditional platinum resistors are often affected by magnetic field interference in such environments, thereby affecting the accuracy of temperature measurement. Taking a 120MW generator in a certain hydropower station as an example, the use of conventional platinum resistors for temperature measurement of its stator is unreliable. In such a strong electromagnetic environment, the temperature measured by platinum resistors may have significant deviations and cannot accurately reflect the actual temperature changes of the generator stator.
Poor adaptability to harsh environments
The operating environment of hydropower stations is usually harsh, with problems such as high humidity and excessive dust. Ordinary temperature sensors are prone to corrosion, damage, and other issues in such environments, which can affect their service life and measurement accuracy. Npr, in humid environments, some electronic component type temperature sensors may experience short circuits or decreased insulation performance due to humidity, resulting in malfunction.

2、 Advantages of Fiber Bragg Grating Temperature Sensor Applied to Stator of Hydroelectric Power Plant Generator
Strong ability to resist electromagnetic interference
Fiber Bragg grating temperature sensors work based on optical principles and have natural immunity to electromagnetic interference. Under the strong magnetic field environment of the generator, the stator temperature can be measured stably and accurately. Due to its independence from the principle of electromagnetic induction, it is not affected by the surrounding electromagnetic field. Even in areas with high magnetic field strength, such as near the stator winding, accurate temperature data can still be obtained, ensuring the reliability of generator stator temperature monitoring.
Corrosion resistance and adaptability to harsh environments
Fiber Bragg gratings themselves have good corrosion resistance, and their materials have strong resistance to harsh environmental factors such as high humidity and dust. This allows it to operate stably near or inside the stator of a hydroelectric power plant generator for a long time, without the need for frequent replacement and maintenance. Npr, when there is water vapor or dust deposited on the sensor around the generator, the fiber optic grating temperature sensor can still sense temperature changes normally and accurately measure them.
High precision measurement
Fiber Bragg grating temperature sensors have high temperature resolution and can accurately measure the temperature changes of the generator stator. This helps to detect small changes in stator temperature in a timely manner, which is of great significance for preventing generator failures. Npr, sensors can be installed in different parts of the stator, such as the stator core, stator winding, and other key positions, to accurately monitor the temperature fluctuations in each part and reduce the risk of faults caused by abnormal temperature.

3、 Specific installation and layout of fiber optic grating temperature sensor for temperature measurement of generator stator in hydropower station

Determine the installation position based on the stator structure
On the lower pressure finger structure of the generator stator, a reasonable installation method should be designed according to the structural characteristics of the pressure finger. Npr, the fiber Bragg grating temperature sensor can be installed in a position that can directly contact the stator winding or where the temperature best reflects the overall temperature condition of the stator. Sensors can be embedded in the slots of the stator winding or installed in close contact with the stator core to ensure that the sensors can obtain accurate temperature information to the maximum extent possible. Meanwhile, considering that the stator is a circular structure, sensors should be evenly distributed in the circumferential direction to comprehensively monitor temperature changes at different angles of the stator.
The rationality and safety of wiring methods
For the wiring of optical fibers, due to the complex working environment of generators, it is necessary to ensure the safety and stable transmission of optical fiber lines. Fiber optic cables can be laid along the surface or pre-set channels inside the stator to avoid being scratched by the generator rotor or affected by other moving parts. U isto vrijeme, it is necessary to provide good protection for optical fibers, such as using armored fibers, to resist external mechanical damage and environmental interference. Collect and analyze temperature data from all sensors by aggregating the optical fibers extracted from each sensor onto monitoring equipment such as fiber Bragg grating demodulator.

4、 Application achievements and impacts of actual cases
Improve the safety and stability of generator operation
Taking a hydropower station as an example, after the transformation of the generator stator temperature measurement system to use fiber optic grating temperature sensors, the stator temperature can be monitored in real time and accurately. When the load of the generator changes or the operating conditions fluctuate, the trend of stator temperature changes can be detected in a timely manner to prevent the occurrence of faults such as overheating. Greatly improving the safety and stability of generator operation, reducing the number of maintenance shutdowns caused by temperature anomalies, and enhancing the power generation efficiency and economic benefits of hydropower stations.
Provide reference models for other hydropower stations
This successful case can provide practical experience reference for other similar hydropower stations. When other hydropower stations upgrade or construct generator stator temperature monitoring systems, they can learn from this method of using fiber optic grating temperature sensors to improve the technical and management level of generator stator temperature monitoring in the entire hydropower industry.

Practical Application of Fiber Bragg Grating Temperature Sensor in Transformer Temperature Measurement

1、 The Importance of Transformer Temperature Measurement and the Defects of Traditional Measurement Methods
（1） The relationship between transformer operation and temperature
The Effect of Temperature on Transformer Components
For transformers, temperature is a key parameter during their operation, as the components of the transformer exhibit different performance at different temperatures. Npr, the lifespan of insulation materials in oil immersed transformers mainly depends on temperature, and excessively high temperatures can cause the insulation materials to age. Osim toga, during the operation of transformers, the temperature distribution of windings is uneven, and overheating faults account for about 63% of the total number of faults. Stoga, accurately measuring the temperature of each part of the transformer is crucial for ensuring its reliable operation.

（2） Shortcomings of Traditional Transformer Temperature Measurement Technology
Inaccurate measurement of winding temperature
When traditional thermal simulation method is used to measure winding temperature, the temperature rise process of the running winding is not exactly the same as the simulation situation, resulting in significant errors. Like traditional winding thermometers, they obtain the superimposed temperature by simulating the top oil temperature of the transformer and the average temperature rise of the winding to the oil. This is only a simulation calculation and cannot accurately measure the hot spot temperature of the transformer winding.
Slow response of oil level thermometer
Traditional oil level thermometers use thermocouples to measure the temperature of transformer oil surface, which has a slow temperature response speed and is difficult to quickly reflect the sudden changes in transformer oil surface temperature. Stoga, they cannot provide accurate temperature basis for operators or automated protection systems in a timely manner, which affects the accurate judgment of transformer operation status.

2、 Advantages of Fiber Bragg Grating Temperature Sensor in Transformer Temperature Measurement

Direct and precise measurement
Fiber Bragg grating temperature sensors have the characteristics of high insulation and are not affected by electromagnetic environment, and can directly measure the changes in the hottest point temperature of transformers. Especially in the hot spots of the internal windings and key heating areas such as the iron core of transformers, temperature changes can be monitored up close and with high precision, and rapid temperature increases can be detected almost without delay. Npr, placing fiber Bragg grating temperature sensors adjacent to the winding can directly obtain local temperature change data of the winding, which is extremely important for analyzing the thermal state of the transformer.
Good compatibility and security
In terms of safety, domestic manufacturers have conducted compatibility evaluation and resistance to breakdown and creepage performance evaluation experiments between fiber Bragg grating temperature sensors and transformer oil. The results show that the fiber Bragg grating temperature sensor can meet the safety requirements in practical applications. Its withstand voltage value in transformer oil meets the standards and can coexist with transformer oil for a long time without affecting the performance of the sensor or damaging the performance of transformer oil due to chemical reactions and other factors. After a 168 hour placement test in oil temperature of 105 ° C and a 2-year long-term placement test in transformer oil, the sensor and its related materials showed no cracking and the oil test results were qualified.
Auxiliary decision-making for determining the operating conditions of transformers
By measuring the temperature of transformers through fiber Bragg gratings, operators can use temperature data as a basis to determine the safe load limit and operating conditions of transformers. Npr, when a transformer is under short-term overload, the temperature time curve corresponding to the transformer load recorded by the fiber Bragg grating temperature measurement system can be used to promptly start cooling equipment such as cooling fans or oil pumps, and provide reference materials for evaluating the remaining service life of the transformer.

3、 Specific installation methods of fiber Bragg grating temperature sensors in different parts of transformers

Winding location
Install 2 fiber optic grating temperature sensors on each phase of the high-voltage winding A, B, and C of the transformer, and place 2 fiber optic grating temperature sensors adjacent to the low-voltage winding. During installation, a groove can be cut on the cushion block with a diameter that can accommodate the fiber optic sensor. Then, the sensor can be fixed using transformer industrial adhesive and secured with kraft paper. Sljedeći, the upper and lower surfaces of the slotted cushion block can be bonded using the uncut groove cushion block. Finally, a wedge can be inserted into the coil to support the space for placing the cushion block. This installation method can evaluate the hot spot temperature of the winding on one hand, and on the other hand, compare whether the temperature measured by two sensors in close proximity to the winding has good consistency.

Iron core and busbar, itd
Install 2 sensors on the iron core, and install 1 sensor on each phase of the three-phase busbar. For the installation of sensors in these areas, it is also necessary to consider the fit and fixing method with the components to ensure that the sensors can accurately measure their temperature. Npr, the sensor can be fixed on the surface of the iron core or busbar by customizing suitable fixtures or brackets, and insulation protection measures should be taken to prevent short circuits or leakage between the sensor and transformer components. Osim toga, installing two sensors on the top and bottom oil temperatures of the transformer can comprehensively monitor the temperature changes of the transformer oil.

4、 Effectiveness verification and operational benefit analysis in practical applications
Accuracy verification of measurement data
In practical application cases, such as the fiber Bragg grating temperature measurement system installed in a 110kV substation in Shenzhen. Experimental results have shown that the fiber Bragg grating temperature measurement system has good fitting performance with traditional temperature measurement instruments, and can fully reflect the operating conditions of transformers during operation. By comparing with the actual operation of transformers and the measurement data of traditional temperature measuring instruments, fiber Bragg grating temperature sensors can accurately measure the temperature of various parts of transformers, providing effective temperature data guarantee for the safe and reliable operation of transformers.

Increase equipment lifespan and enhance operational reliability
Due to the accurate and timely temperature monitoring of transformers by fiber Bragg grating temperature sensors, it can effectively avoid faults such as accelerated aging of insulation materials and winding short circuits caused by overheating of transformers. This can extend the service life of the transformer and reduce the maintenance and replacement costs of the transformer. U isto vrijeme, accurate temperature monitoring also enables transformers to maintain a specified temperature range during operation, improving the reliability of the entire transformer operation, reducing the probability of unexpected power outages and other accidents, and ensuring the stable operation of the power system.

Practical Application of Fiber Bragg Grating Temperature Sensor in Temperature Measurement of Experimental Equipment

1、 Special requirements for temperature measurement in experimental equipment
High precision measurement requirements
In scientific research and industrial experiments, many experimental equipment require extremely high temperature measurement accuracy. Npr, in the field of materials science, small temperature changes during performance testing of certain special materials (such as superconducting materials, nanomaterials, itd.) may have a significant impact on experimental results. The superconducting transition temperature of superconducting materials is usually in a very low temperature range, and precise temperature measurements at the millikelvin level are required to accurately observe the transition of superconducting properties and their transition temperature range. Fiber Bragg grating temperature sensors have high temperature resolution and can meet the needs of high-precision measurements. Fiber Bragg grating temperature sensors based on phase sensitive detection technology can even achieve ultra-high sensitivity measurements at the sub millikelvin level, thereby accurately grasping the characteristic changes of materials at different temperatures.
Low electromagnetic interference requirements
Near some electronic related experimental equipment, such as electron microscopes, mass spectrometers, itd., there are precision electronic components and complex electromagnetic environments inside. If normal temperature measurement tools are sensitive to electromagnetic interference, it will affect their measurement accuracy or cause interference to the equipment itself. Fiber Bragg grating temperature sensors are naturally immune to electromagnetic interference due to the use of optical signals for temperature sensing. They can accurately measure temperature around these experimental equipment that require strict electromagnetic environments without interfering with the operation of the equipment.
Convenience of simultaneous measurement at multiple points
Some large experimental equipment, such as large wind tunnel experimental equipment, car collision test equipment, itd., have uneven temperature field distribution inside. It is necessary to monitor the temperature at multiple different locations simultaneously in order to comprehensively understand the temperature distribution inside the equipment and its impact on the experimental results. Fiber Bragg Grating temperature sensors can be fabricated on a single optical fiber with multiple grating sensors of different wavelengths, each sensor corresponding to a code. Through wavelength division multiplexing technology, up to 20 fiber Bragg grating sensors can be connected in series on a single optical fiber, making it convenient to achieve multi-point temperature measurement in different parts of experimental equipment and minimizing the complexity of measurement wiring.

2、 Advantages of Fiber Bragg Grating Temperature Sensor for Experimental Equipment Characteristics
Adapt to special environments
In some special experimental environments, such as corrosive gas environments in chemical laboratories or ultra-high temperature and high pressure environments in high-temperature and high-pressure reaction vessels, fiber Bragg grating temperature sensors have strong adaptability. Its corrosion resistance, high pressure resistance, and ability to operate normally in relatively harsh environments make it suitable for use in these special experimental equipment. Npr, in corrosive gas environments, there is no need to worry about the sensor being corroded and affecting measurement accuracy. It can also accurately measure temperature in high-temperature and high-pressure reactors, unlike traditional metal temperature sensors that may deform, be damaged, or have inaccurate readings due to high temperature and pressure.
Small size and flexibility
Fiber Bragg grating temperature sensors have a small volume and high flexibility, which allows them to be installed on some experimental equipment with limited space or in narrow spaces inside experimental devices. Npr, inside the Lab-on-a-Chip device, due to the extremely small space, ordinary temperature sensors may not be able to be installed. Međutim, fiber Bragg grating temperature sensors can be easily installed inside the device with their small size, achieving temperature monitoring of the micro environment inside the device, thereby providing temperature data support for studying chemical or biological reactions inside the chip.

3、 Application examples in different types of experimental equipment
Biological experimental equipment
In a biological incubator, precise control and monitoring of the internal temperature environment are required to facilitate the growth and reproduction of microorganisms or cells. Fiber Bragg grating temperature sensors can be installed at different levels or corners inside the incubator to accurately measure the temperature in different areas. In some biomedical imaging devices, such as those involved in studying temperature changes in biological tissues (such as temperature detection of biological tissues during laser hyperthermia), fiber Bragg grating temperature sensors can approach biological tissues in a non-invasive or minimally invasive manner and measure their temperature changes, providing accurate local temperature data to meet the needs of biomedical research. Its accuracy is of great significance for studying tissue physiological responses, itd.
Physics experimental equipment
Monitoring of ultra-low temperature environments is crucial in low-temperature physics laboratories. Fiber Bragg grating temperature sensors can be used to measure the temperature around and inside low-temperature equipment such as liquid helium cooling devices, superconducting magnet cooling systems, itd. In high-energy physics experimental equipment, such as large particle accelerators, there are numerous electronic devices and superconducting components inside, and temperature monitoring during their operation is crucial. Fiber Bragg grating temperature sensors can accurately measure the temperature of different parts in the complex strong electromagnetic environment inside the accelerator, ensuring the normal operation of the equipment.
Chemical experimental equipment
For reaction vessels in chemical synthesis experiments, especially in high-temperature and high-pressure reaction processes, fiber Bragg grating temperature sensors can be installed inside or on the walls of the reaction vessel to monitor the reaction temperature in real time. In gas chromatography or liquid chromatography, fiber Bragg grating temperature sensors can be used for precise control and monitoring of the column temperature inside the instrument, as the column temperature directly affects the separation efficiency and analysis results of the sample. Through high-precision temperature measurement, the accuracy and reliability of chemical analysis can be improved.

 

3、Practical Application of Distributed Fiber Optic Temperature Sensor

Application of Distributed Fiber Optic Temperature Sensor in Long Distance Pipeline Temperature Measurement

1、 The demand and challenges of long-distance pipeline temperature measurement
Long distance pipelines play a crucial role in many industries, such as oil transmission pipelines and natural gas transmission pipelines. Accurately understanding the temperature conditions of these long-distance pipelines is a key factor in ensuring their safe and efficient operation. Due to the possibility of pipelines crossing various complex geographical environments such as mountains, deserts, rivers, itd., traditional temperature measurement methods face many challenges. Traditional point sensors are difficult to achieve comprehensive and continuous monitoring of long-distance pipelines, and are costly and difficult to maintain in long-distance layouts; Osim toga, long-distance pipelines may face different geological and climatic influences, which can easily lead to abnormal local temperature changes. Npr, the thermal conductivity characteristics of the geological layers through which the pipeline passes may be different, or there may be temperature differences in some parts of the pipeline under sunlight and shadow. Traditional sensors cannot quickly and accurately reflect these changes.

2、 The principle of distributed fiber optic temperature sensor
The working principle of distributed fiber optic temperature sensors is based on the scattering effects of various fibers, mainly including Raman scattering, Brillouinovo raspršenje, itd. Under the principle of Raman scattering, when a laser pulse is sent into an optical fiber, the laser interacts with molecules in the fiber to produce Raman scattering light, including Stokes light and Anti Stokes light. Stokes light is temperature insensitive, while the intensity of anti Stokes light is temperature dependent and has different wavelengths. By measuring the ratio of Anti Stokes to Stokes intensity, accurate temperature information can be obtained. When based on the principle of Brillouin scattering, temperature information can also be obtained by detecting parameters such as the frequency shift of Brillouin scattering light. Osim toga, these sensors can also measure the echo time of scattered signals based on optical time domain reflectometry (OTDR) Tehnologija, thereby determining the specific positions of different scattering points on the optical fiber and obtaining the temperature distribution along the entire fiber path. Npr, using this technology can enable distributed fiber optic sensors to measure temperature changes at numerous locations along a long pipeline, obtaining a detailed pipeline temperature “profile”.

3、 Practical application cases and advantages
Detecting pipeline leaks
Npr, in the case of oil pipeline engineering, a long-distance oil pipeline stretches for hundreds of kilometers, and once a leak occurs, it is often accompanied by abnormal temperature changes. Distributed fiber optic temperature sensors can accurately locate the possible leakage location in real time (the positioning accuracy can reach meter level or even better according to the actual system), because the oil leakage at the leakage point will change the surrounding temperature distribution. The sensor sensitively captures temperature changes, allowing workers to quickly take measures to avoid large-scale oil leakage causing environmental pollution and economic losses.
The advantage lies in the fact that compared to traditional leak detection methods such as pressure balance, distributed fiber optic temperature sensors are based on temperature detection and are not affected by complex fluid pressure changes in pipelines. They can effectively monitor slow or small leaks.
Distinguish pipeline operation parameters
In terms of natural gas transmission pipelines, changes in parameters such as flow rate and pressure during pipeline operation are often correlated with temperature. Through distributed continuous measurement of pipeline temperature, the operational status of the pipeline can be indirectly inferred. Npr, when the flow rate is normal, the temperature distribution of the pipeline will be in a relatively stable range; If an abnormal increase or decrease in temperature is detected in a certain section of the pipeline, it may indicate that the internal airflow is obstructed or there is external interference (such as third-party construction damaging the pipeline insulation layer), which can help adjust the operation strategy in a timely manner and ensure the safe and efficient transportation of the pipeline.
Its advantages are reflected in the fact that this method of discriminating other operating parameters based on temperature measurement is a non-invasive detection method that does not change the physical properties of the flow inside the pipeline and has minimal interference with normal operation; And it can obtain real-time and all-round data (along the entire fiber optic sensing line), providing a comprehensive and intuitive reflection of the pipeline operation status.
Prevent different risks from harming pipelines
When oil pipelines pass through seismic active zones or landslide areas, natural disasters such as earthquakes and landslides may cause pipeline deformation and local stress increase, which may generate heat and be monitored by distributed fiber optic temperature sensors. Osim toga, in areas that are often subject to third-party interference (such as oil theft and attempts to damage pipelines), there are often signs of temperature changes before the pipeline is damaged (such as local changes in oil temperature caused by oil theft drilling).
The advantage lies in the fact that compared to traditional methods of installing individual sensors at specific locations to monitor the impact of different risks on pipelines, the long and continuous monitoring of distributed fiber optic temperature sensors can detect potential problems in the early stages of various pipeline hazards, thus adapting to the complex and dynamically changing risk environment of long-distance pipelines.

Application of Distributed Fiber Optic Temperature Sensor in Cable Tray Temperature Measurement

1、 The importance of temperature measurement for cable trays
Cable tray is the infrastructure that carries and protects cables, and is widely used in power transmission and electrical facility layout. Tijekom rada, cables generate heat due to their own current carrying capacity. If the heat dissipation conditions are poor, the cable layout is too dense, or there are cable joint faults, it is easy to cause excessive temperature. Excessive temperature of cables in cable trays can bring many risks, such as accelerating the aging of cable insulation and reducing the service life of cables; In severe cases, it may cause fires, especially in places where power facilities are concentrated (such as substations, large industrial plants, itd.). Once cables catch fire, it can easily cause power outages, affect production and life, and endanger personnel safety and equipment asset safety.

2、 The Implementation of Distributed Fiber Optic Temperature Sensor Principle in Cable Tray Temperature Measurement
In the temperature measurement scenario of cable trays, distributed fiber optic temperature sensors still mainly use the principle of Raman scattering. When optical fibers are installed near cable trays or laid between cables, the intensity of anti Stokes light in Raman scattering changes due to changes in ambient temperature, allowing for accurate measurement of temperature information. Due to the small and flexible nature of optical fibers, they can be easily laid inside or along the edges of cable trays, and can adapt well to different shapes and curvatures of cable trays, thereby achieving comprehensive and flexible temperature monitoring of cables on cable trays.

3、 Application methods and effects
Real time monitoring and early warning
Npr, in cable trays of some large commercial buildings or data centers, distributed fiber optic temperature sensors achieve 24-hour uninterrupted real-time monitoring. When there is an abnormal increase in cable temperature (such as a cable joint starting to heat up due to loose contact), the sensor can promptly capture small temperature changes (temperature resolution can reach 0.5 ℃ or higher accuracy) and immediately send alarm information to the monitoring system. Different levels of temperature alarm thresholds can be set, such as setting a lower alarm temperature for general overload and a higher level alarm for approaching the temperature of cable insulation damage.
Enable operation and maintenance personnel to detect potential hazards in advance and take timely response measures, such as adjusting cable loads, repairing faulty joints, itd., to avoid continuous temperature rise causing fires or cable damage.
Multi point measurement and precise positioning
Multiple cables are often laid in parallel on cable trays, and distributed fiber optic temperature sensors can be installed along the trays to achieve multi-point measurement. Npr, for a cable tray that is tens or even hundreds of meters long, sensors can obtain the temperature of each corresponding cable (or cable segment, cable joint, itd.) through different positions on the optical fiber, and can locate which cable or cable position is experiencing temperature problems. The positioning accuracy can reach meter level or even higher.
This is crucial for large cable tray systems, especially those facilities that contain complex cable layouts (such as cable tunnel tray systems in large substations), as it can reduce the time and labor costs of troubleshooting, allowing for quick and effective handling of problematic cables.
Adapt to complex environments
Distributed fiber optic temperature sensors can work normally in both indoor cable tray environments with electrical interference and outdoor cable tray environments that may be affected by factors such as wind, kiša, and temperature changes. The electrical insulation, electromagnetic interference resistance, and good corrosion resistance of optical fibers enable sensors to be unaffected by electromagnetic interference generated by electrical equipment near the bridge, and also have good adaptability to harsh weather environments or corrosive substances such as anti-corrosion paint on the bridge itself.
In some chemical industrial plants, cable trays may have corrosive gases or high humidity environments. Distributed fiber optic temperature sensors can ensure long-term stable temperature monitoring and safeguard the safe operation of cables.

Application of distributed fiber optic temperature sensor in temperature measurement of bus duct

1、 The structural characteristics of busbar trunking and the necessity of temperature measurement
Bus duct is an efficient device for transporting electrical energy, consisting of copper or aluminum bus columns, mainly used to distribute electrical energy to various components of a distributed system. The internal current of the bus duct is relatively high, and heat will be generated during operation due to various reasons. Npr, if there is poor contact at the connection point of the bus duct, according to Joule’s law, an increase in resistance at the connection point will generate more heat under constant current; Long term overload operation or poor heat dissipation conditions of bus ducts can also lead to local high temperatures. When the temperature of the bus duct is too high, it may ignite the surrounding flammable materials, causing a fire and endangering the safety of personnel and property; Excessive temperature may also cause the temperature of the casing and other components of the bus duct to rise. If personnel come into contact with overheated bus ducts without knowing it, safety accidents such as burns may occur, especially in industrial sites or densely populated commercial buildings where this risk needs to be taken seriously; Osim toga, excessively high temperatures can also affect the performance and lifespan of bus ducts, which is not conducive to the normal operation of equipment. So, it is necessary to monitor the temperature of the bus duct.

2、 Temperature measurement mechanism of distributed fiber optic temperature sensor
Distributed fiber optic temperature sensor is based on Raman scattering for temperature measurement of bus ducts. After installing optical fibers near the bus duct, when the bus duct generates heat and causes temperature changes around the fiber, the anti Stokes intensity in Raman scattering light changes. Based on the pre calibrated relationship between temperature and intensity, the temperature value can be accurately measured. And with the help of optical time domain reflection technology, the position of each temperature measurement point on the optical fiber can be determined, thereby accurately obtaining the temperature distribution at different positions of the bus duct (such as bus duct joints, different sections of the bus duct, itd.). Meanwhile, due to the continuous laying of optical fibers in distributed fiber temperature sensors, continuous distributed measurement of bus duct temperature can be achieved.

3、 The effectiveness and value of the application
Real time temperature monitoring and safety assurance
In the busbar trunking system of industrial plants or commercial buildings, distributed fiber optic temperature sensors can monitor the temperature of the busbar trunking in real time. Taking the power supply system bus duct of a large factory as an example, if a certain bus duct section experiences an increase in current and temperature due to aging of some components during long-term operation, the sensor can immediately detect the temperature change. When the temperature reaches the pre-set safety threshold (such as setting an alarm threshold in advance for the heat-resistant temperature of the busbar insulation material), the system will promptly issue an alarm signal.
This greatly improves the safety of bus duct operation, avoiding fires or other safety accidents caused by local high temperatures, and effectively ensuring the safety of personnel’s lives and property.
Intelligent operation and maintenance assistance
In many power supply facilities, maintenance of bus ducts is an important task. The temperature data provided by distributed fiber optic temperature sensors helps achieve intelligent operation and maintenance. Npr, by continuously collecting temperature data of the bus duct at different time periods and under different loads, a temperature change model can be established. By using these data, it is possible to predict the location of potential faults in the bus duct (such as long-term locations with large temperature fluctuations or high temperatures that may be potential fault points), and operation and maintenance personnel can arrange targeted preventive maintenance work based on this, rather than waiting until the fault occurs for repair.
Thereby improving the reliability of bus ducts, extending the service life of equipment, reducing power outage losses and maintenance costs caused by sudden failures, and enhancing the stability of the entire power supply system.
Meet special environmental requirements
In some special environments, such as industrial sites with explosion-proof requirements, temperature monitoring of bus ducts requires special sensors. The fiber optic of distributed fiber optic temperature sensors has inherent safety, electromagnetic interference resistance, and corrosion resistance, making them very suitable for temperature measurement in such environments. Because it can withstand electromagnetic interference and corrosive substances in the environment, while avoiding the risk of explosion caused by electric sparks like traditional electronic sensors.
Distributed fiber optic temperature sensors can also work reliably for temperature monitoring of bus ducts in special environments such as offshore platforms and underground mines, ensuring the safe operation of bus ducts.

Application of Distributed Fiber Optic Temperature Sensor in Oil Pipeline Temperature Measurement

1、 Characteristics and temperature measurement significance of oil pipelines
Oil pipelines play a crucial role as a link in the extraction, transportation, and storage of oil. Petroleum has hazardous characteristics such as flammability and explosiveness. Once there is a problem with the pipeline, such as leakage or pipeline rupture caused by high temperature, it may trigger a series of serious safety accidents, such as fires and explosions, which not only cause huge economic losses but also pose a serious threat to the environment and personnel. Osim toga, the flow state and physical and chemical properties of oil in pipelines are often closely related to temperature. Npr, temperature changes may affect the viscosity of oil, thereby affecting the transport capacity of pipelines; At different stages of reservoir development, from oil wells to gathering and transportation pipelines, there are different normal ranges of oil temperature. Mastering these temperature information can help optimize production and transportation plans.

2、 Measurement principle and technical characteristics of distributed fiber optic temperature sensor
Distributed fiber optic temperature sensors still use the principle of Raman scattering or Brillouin scattering in oil pipeline temperature measurement. In terms of Raman scattering, when a light pulse is transmitted in an optical fiber, it interacts with fiber molecules to produce Raman scattering light. The anti Stokes intensity is modulated by temperature, and its ratio to the Stokes intensity can reflect temperature information. For Brillouin scattering, temperature data is obtained based on the correspondence between Brillouin frequency shift and temperature; And accurately locate the positions of various temperature measurement points on the optical fiber through optical time domain reflection technology. Distributed optical fibers have the ability to measure continuously over long distances and can fully cover the long-term layout of oil pipelines, enabling dynamic monitoring of temperature along the pipeline.

3、 Specific application achievements and unique value
Temperature monitoring of oil storage tanks
In terms of oil storage tanks, traditional temperature monitoring methods require placing a large number of temperature sensors in the tanks, which not only results in high costs, but also has problems such as high errors and difficult maintenance. When using distributed fiber optic temperature sensors, only one fiber optic cable needs to be buried in the storage tank to monitor the temperature inside the entire tank.
This not only saves sensor costs and layout space, but also improves the accuracy and reliability of monitoring, which is conducive to timely understanding the temperature status of oil in the storage tank, avoiding danger caused by abnormal temperature, such as excessive temperature that may increase oil evaporation and increase safety risks.
Refinery pipeline temperature monitoring
There are a large number of high-temperature equipment and pipelines in refineries, and traditional temperature monitoring methods require the installation of many sensors and are difficult to maintain and replace. Distributed fiber optic temperature sensors are different from traditional methods, as they only require burying one fiber optic cable to monitor the temperature of the entire pipeline network inside the refinery.
Accurately grasping the temperature changes during the petroleum processing in pipelines, such as temperature control in processes such as crude oil heating and refining and various oil separation, is crucial. Based on the data provided by distributed fiber optic temperature sensors, process parameters can be optimized to improve refining efficiency while ensuring safety.
Monitoring of temperature gradient from the bottom of the oil well to the wellhead
In terms of oil wells, distributed fiber optic temperature sensors can obtain detailed temperature gradient data from the bottom of the well to the wellhead after laying optical fibers along the oil well tubing. This is very valuable for reservoir engineering, npr, by analyzing temperature gradient curves, information such as the interlayer conditions between oil layers and the flow patterns of liquids inside the oil layers can be determined.
In water injection wells, it is also possible to understand the interaction between the temperature changes of injected water at different depths and the formation temperature, in order to improve water injection strategies, enhance oil recovery efficiency, and protect oil reservoirs.

Application of Distributed Fiber Optic Temperature Sensor in Heating Pipeline Temperature Measurement

1、 Operation characteristics and temperature measurement requirements of heating pipelines
Heating pipelines are an important component of urban heating systems that transport thermal energy such as hot water or steam. During the winter heating period, the heating pipeline continues to operate, and the temperature of the hot water or steam inside the pipeline is high and greatly affected by the external environmental temperature. Npr, in the cold winter, heating pipelines need to pass through various areas with low external environmental temperatures such as the ground and underground. If the insulation effect of the pipeline is poor or the pipeline malfunctions (such as pipeline corrosion, leakage, itd.), it will cause heat loss, resulting in a decrease in heating efficiency and energy waste. Osim toga, local overheating or excessive temperature of heating pipelines may damage the insulation layer of the pipelines or the structure of the pipelines themselves (such as temperature stress causing pipeline expansion, deformation, and rupture), leading to safety hazards such as leaks. Stoga, accurate monitoring of the temperature of heating pipelines is crucial for ensuring heating quality, saving energy, and ensuring safe system operation.

2、 Adaptability of the working principle of distributed fiber optic temperature sensors
Distributed fiber optic temperature sensors work using Raman scattering or Brillouin scattering principles, making them highly suitable for temperature measurement needs in heating pipelines. When the temperature around the heating pipeline changes, the scattering characteristics in the optical fiber also change, and temperature information can be obtained by measuring the ratio of Anti Stokes to Stokes intensity (Raman scattering principle) or detecting the frequency shift of Brillouin scattering light (Brillouin scattering principle). Osim toga, by utilizing optical time domain reflection technology to determine the positions of temperature measurement points on the optical fiber, temperature distribution detection of the entire heating pipeline can be achieved. And optical fibers can be conveniently laid outside or inside the heating pipeline (such as introducing optical fibers into the pipeline in advance during the pipeline manufacturing process, of course, laying them outside is relatively convenient for later maintenance and installation), achieving comprehensive coverage temperature monitoring of the heating pipeline.

3、 Actual effectiveness in heating pipelines
Rapid detection and localization of temperature anomalies
If the heating pipeline experiences abnormal temperature changes at a local location due to internal scaling, external mechanical impact, or damage to the insulation layer (such as local overheating or sudden temperature drops), distributed fiber optic temperature sensors can quickly detect this temperature difference. Npr, in a large-scale urban heating network, if a certain section of the underground heating pipeline is accidentally damaged by construction machinery, the temperature around the pipeline will rapidly drop, and the sensor can capture this change in a timely manner.
And accurately locate the location where abnormal temperatures occur (the positioning accuracy can reach meter level accuracy according to the actual system), which allows heating companies to quickly dispatch maintenance personnel for repairs, reduce heat loss, minimize the impact on user heating, and avoid greater safety issues caused by continuous pipeline damage.
Optimizing heating system operation and energy conservation
Continuous temperature monitoring of heating pipelines through distributed fiber optic temperature sensors can collect a large amount of data on pipeline temperature, including temperature changes in different time periods and areas. Npr, based on these temperature data, a temperature map of a heating pipeline network can be drawn to understand the heat transfer losses of each section of the heating pipeline.
Heating companies can adjust the flow distribution of heating near and far ends based on these data, optimize the operating parameters of heating pumps, thereby achieving reasonable heat distribution, improving heating efficiency, and reducing energy waste. U isto vrijeme, it is also possible to predict in advance the parts of the pipeline that may need maintenance or replacement based on temperature data, achieving preventive maintenance and extending the service life of the pipeline.

Application of Distributed Fiber Optic Temperature Sensor in Submarine Cable Temperature Measurement

1、 The special environment and temperature measurement requirements of submarine optical cables
Submarine optical cables are used to achieve important functions such as intercontinental communication connections, and they are located in complex and harsh underwater environments. The water pressure on the seabed is enormous, and seawater has a corrosive effect on optical cables. Osim toga, factors such as seabed temperature and geological movements constantly affect the condition of optical cables. Temperature is a very important parameter for submarine optical cables, as temperature changes can cause changes in the optical properties of the fiber, such as fluctuations in the refractive index of the fiber with temperature changes, which can interfere with the transmission of optical signals. Osim toga, submarine optical cables may experience temperature anomalies due to external environmental thermal erosion (such as submarine volcanic activity, hydrothermal vents, and other ocean current factors) or the generation of heat during their own operation (such as the heat generated by current during signal transmission). If the temperature is too high, it can affect the service life of the optical cable, and in severe cases, it may cause damage to the optical cable and communication interruption. Stoga, accurate monitoring of the temperature of submarine optical cables is crucial for ensuring their normal operation and maintaining communication security.

2、 Principle and deployment characteristics of distributed fiber optic temperature sensors
Similar to other application scenarios, distributed fiber optic temperature sensors are mainly based on Raman scattering or Brillouin scattering principles for temperature measurement in submarine cables. Under the principle of Raman scattering, temperature information is obtained by measuring the ratio of Stokes light intensity to anti Stokes light intensity; Under the principle of Brillouin scattering, temperature is determined by the relationship between Brillouin frequency shift and temperature. The deployment of optical fibers in submarine cables can utilize the existing optical fibers for temperature monitoring (i.e. sharing a portion of the fiber segment for sensing and communication functions), or a dedicated bundle of optical fibers for temperature detection can be laid. Cleverly, this distributed fiber optic temperature sensor can achieve continuous temperature measurement along the entire length of the submarine cable, and accurately locate any location where temperature anomalies occur using optical time domain reflection technology.

3、 The application value in actual operation and protection
Early warning and maintenance of faults
When the submarine optical cable is about to fail due to external interference (such as scratching the submarine optical cable by fishing trawling operations, or stress applied to the optical cable by submarine crustal activity), small temperature changes are often generated inside or outside the cable structure (such as heat generated by stress, frictional heat generated by internal structural deformation, itd.). Distributed fiber optic temperature sensors can sensitively capture these initial temperature anomalies. Npr, in a transoceanic submarine cable communication project, if a submarine earthquake occurs nearby, although the initial vibration may be small, it may have already caused potential stress or slight structural damage to the submarine cable, resulting in temperature changes.
Sensors can detect these changes in advance and send warning signals to the ground monitoring center in a timely manner. Operations personnel can take protective measures before faults occur, such as adjusting signal transmission protocols to avoid signal transmission being affected, or sending maintenance ships to the sea area where faults may occur for inspection and reinforcement of optical cables.
Monitor areas with thermal anomalies to ensure smooth operation
There are some areas of thermal anomalies on the seabed, such as submarine volcanoes, hydrothermal activity zones, itd. When submarine cables pass through these areas, if the thermal effect is too strong, it may damage the cables. Distributed fiber optic temperature sensors continuously monitor the temperature changes of optical cables in these areas. Once the temperature approaches or exceeds the critical temperature that the optical cable can withstand (different safety temperature thresholds are set according to the design materials and parameters of the optical cable).
It will trigger an alarm and guide the operation and maintenance personnel to take special measures, such as strengthening the cooling measures of the optical cable in the area (such as using seawater circulation devices, itd.), to ensure that the submarine optical cable can also operate normally and safely in areas with thermal anomalies, thereby ensuring the stability of international communication.