High resolution distributed temperature sensing

high-resolution DTSThe fiber Bragg grating distributed temperature sensing on gas-insulated line spacer influences surfaces charge accumulation. Nevertheless, it is very difficult to perform the DTS measurement because the traditional electric sensors have huge dimensions, they are difficult to multiplex and highly sensitive to electromagnetic interference.

Thus, a distributed temperature sensing system of the GIL spacer based on the technology of the optical frequency domain reflectometry was designed to solve the challenges. The operation of the DTS system is based on the ultra-weak fiber Bragg grating or FBG technology to change single-mode optical fiber because of its higher signal-noise ratio.

It should be noted that the distributed temperature sensing also used the demodulation technique to compensate for the nonlinear frequency tuning errors caused by the unstable tunable laser. Therefore, the DTS system allows determining the connection between the space temperature and the wavelength shift during the calibration test.

Additionally, the distributed temperature sensing includes the application of the data processing technique for 3D surface temperature on a cone-type spacer. Finally, the DTS system based on FBG technology enables to obtain efficiently high-resolution temperature measurements on the spacer surface with the help of the optical frequency domain reflectometry, which is virtually impossible to perform with the traditional electric temperature sensing systems.

Nowadays the technology of direct current transmission with the gas-insulated line is an effective way due to its low electrical losses compared with, for example, AC transmission. That is why the distributed temperature sensing is considered to be a key factor that should be known first.

To be more precise, the disadvantages of traditional electric sensing systems such as dimensions, multiplexing, and sensitivity to EMI are solved by optical fiber sensing in electrical engineering. Fiber Bragg grating technology is a precise optical temperature sensing technique widely applied. But there are some limits in the multiplexing ability of conventional FBG sensors.

The new distributed temperature sensing system includes ultra-weak fiber Bragg gratings providing a reflectivity of only 0.1% compared to the conventional FBG sensors. Compared to the optical frequency domain reflectometry based on the Rayleigh technology, “ultra-weak FBG can achieve higher signal-noise ratio since the reflection of ultra-weak FBG sensor is much higher than the backscattering in the optical fiber”.

Optromix is a manufacturer of innovative fiber optic products for the global market. The company provides the most technologically advanced fiber optic solutions for the clients. Optromix produces a wide range of fiber optic devices, including cutting-edge customized fiber optic Bragg grating product line and fiber Bragg grating sensor systems. Moreover, Optromix is a top choice among the manufacturers of fiber Bragg grating monitoring systems. If you have any questions, please contact us at info@optromix.com

Distributed temperature sensing for the fog detection

DTS for the fog detectionTraditional in situ observations of meteorological variables are limited by surface levels, herein, it is possible to carry out the lowest observation around just 1-m height. Therefore, observation results of both shallow fog, and the initial growth stage of thicker fog layers can be missed in this case. Nevertheless, the use of distributed temperature sensing or DTS technology allows measuring temperature and humidity parameters at centimeter resolution in the lowest 7 m.

It should be noted that it is very important to obtain high-resolution observation for radiation fog, and DTS sensors solve the problem. Two techniques are applied to make tests in the near-surface layer at a higher resolution than the traditional sensing devices.

Distributed temperature sensing is ideal for the measurement temperature and relative humidity parameters. DTS technology offers a high spatial and temporal resolution. DTS application includes detection of surface temperature and soil heat fluxes, the radioactive skin effect at the surface of water bodies, the Bowen ratio, near-surface turbulent fluxes under varying stability, and wind speed.

The combination of distributed temperature sensing with unmanned aerial vehicle provides the observation of the morning boundary-layer transition from stable to unstable conditions. Compared to traditional sensing techniques, DTS technology has a great advantage for studies of the stable boundary layer that is the resolution of steep gradients.

DTS sensors are able to detect shallow cold pools at high resolution that is the mark of radiation fog formation. The thing is that the fog presence causes elevated DTS temperatures of up to 0.7 ℃ when compared to traditional temperature parameters. However, the technology of distributed temperature sensing is required to be further tested to provide its reliability under stable, foggy conditions.

DTS devices enable to measure temperature characteristic along with optical fiber cables that are based on the backscattered signal of a laser pulse. The DTS sensors were tested, herewith, the optical fiber includes two multi-mode cores, while a simple single-ended (non-duplexed) configuration is applied for the measurements.

Finally, even in the conditions of fog formation absence, compared to DTS technology traditional sensing devices are not able to measure the strong temperature inversions in the lowest 1 m of air. Distributed temperature sensing provides an efficient solution to the problem.

The application of DTS systems is not limited by fog detection, but the broader near-surface (stable) boundary layer. Additionally, DTS sensors offer a better physical understanding of such processes as the collapse of turbulence at the onset of the stable boundary layer, intermittent turbulence within the stable boundary layer, and the transition between different boundary-layer regimes due to the ability of distributed temperature sensing to catch steep gradients in both temperature and relative humidity parameters.

If you want to obtain a highly efficient distributed temperature sensing system, you should choose the Optromix company. Optromix is a manufacturer of innovative fiber optic products for the global market. The company provides the most technologically advanced fiber optic solutions for monitoring worldwide. Optromix is a fast-growing vendor of fiber Bragg grating (FBG) products line such as fiber Bragg grating sensors, FBG interrogators and multiplexers, distributed acoustic sensing (DAS) systems, distributed temperature sensing (DTS) systems. If you are interested in DTS systems and want to learn more, please contact us at info@optromix.com

Distributed temperature sensing of fiber optics under harsh conditions

DTS in harsh conditionsAccording to a recent study, the technology of distributed temperature sensing allows demonstrating the mechanical properties of fiber optics under harsh conditions. The fact is that numerous land and undersea oil procedures depend heavily on distributed temperature sensing for providing safety and functionality in severe environments.

Usually, the manufacturers use silica-based fiber optics for distributed temperature sensing and distributed acoustic sensing, where temperature and acoustic signals are transmitted and recorded continuously along the length of fiber sensor cable. Such fiber optic solution for FBG interrogator of 15 km length enables well and pipeline operators to apply fiber-based distributed sensing technology to measure the whole wellbore or pipeline span with a resolution of 1 m or less virtually in real-time.

For example, the technology of distributed temperature sensing with fiber optics is used in the operation of steam-assisted gravity drainage or SAGD technique, in which the main goal is the production of heavy crude oil and bitumen materials. Nevertheless, it is only one example, while distributed temperature sensing has numerous fiber optic applications.

It should be noted that the distributed temperature sensing system monitors the following extreme environments while optical fiber operation: high temperatures and pressures, ionizing radiation, and aggressive chemicals in the environment. However, in order to be applied in such severe conditions, fiber optics have to be highly reliable, while transmitting optical power with a minimum of added signal loss.

Most of the fiber sensor cables used in fiber optic applications contain a silica-based core and cladding because of the silica benefits that include high optical fiber transmission, superior thermal stability, and mechanical reliability. Herewith, the use of a polymer coating in fiber cables provides the mechanical protection of fiber optics and minimization of bend-induced optical attenuation.

The technology of distributed temperature sensing also enables to detect the factors limiting the performance of fiber optic cables at elevated temperatures and/or in aggressive conditions. The most frequent failures for fiber optics are related to added attenuation or loss of mechanical strength. Herewith, failure criteria differ from each other and depend on the type of fiber optic application.

If you want to obtain a highly efficient distributed temperature sensing system, you should choose the Optromix company. Optromix is a manufacturer of innovative fiber optic products for the global market. The company provides the most technologically advanced fiber optic solutions for monitoring worldwide. Optromix is a fast-growing vendor of fiber Bragg grating (FBG) products line such as fiber Bragg grating sensors, FBG interrogators and multiplexers, distributed acoustic sensing (DAS) systems, distributed temperature sensing (DTS) systems. If you are interested in DTS systems and want to learn more, please contact us at info@optromix.com

DTS system controls oil rim movement

DTS for oil rim detectionToday operators in highly fractured carbonate reservoirs use running wireline gradiometric surveys as a traditional way of oil-rim movement monitoring. Nevertheless, the method is not ideal because it does not allow providing the necessary information in a manner timely enough to influence operations since the surveys are conducted just a few times a year. Distributed temperature sensing (DTS) system is an alternative solution that overcomes these drawbacks.

Distributed temperature sensing offers real-time monitoring of the oil rim in carbonate reservoirs. DTS technology is based on the use of optical-fiber Bragg gratings (FBGs) and is able to measure pressure in extreme environmental conditions. It should be noted that the DTS system does not require electronics, herewith it provides long service term even at elevated downhole temperatures. Also, distributed temperature sensing is quite stable, it can determine even small pressure changes.

Moreover, dozens of distributed temperature sensors can be implemented on one fiber optic cable connected to the FBG interrogator. The principle of operation includes a diaphragm pressure transducer that converts changes in the hydrostatic pressure of its environment into the deformation of a pressure-sensitive diaphragm, and then into the strain, within an optical fiber attached to the diaphragm. The thing is that optical fibers offer numerous advantages for oil and gas industry application, containing the following:

  • high transmission efficiency that means the FBG interrogator can be installed several kilometers away from the downhole sensors;
  • high data quality and accuracy due to data encoding in the light wavelength;
  • data immunity to the electromagnetic influence by machines;

At present time the information about pressure and temperature measurements, as well as system-health and self-diagnostic information are transmitted from the FBG interrogator into a database at 3-hour intervals. If fresh data sets are obtained, an algorithm processes them into gas/oil-contact and oil/water-contact locations. Also, it is possible to visualize pressure, temperature, and fluid-level data to see them in real-time.

Further improvement of the DTS system will allow the application of the system for the production monitoring in ultrahigh-temperature thermal-recovery wells, where fluid temperatures up to 280 °C can be reached. Finally, distributed temperature sensing provides the reduction of a production delay, the reduction of operational costs, health, safety, and environmental risk reduction, and the possibility of system expansion.

Optromix is a fast-growing vendor of fiber Bragg grating (FBG) product line such as fiber Bragg grating sensors, FBG interrogators and multiplexers, Distributed Acoustic Sensing (DAS) systems, Distributed Temperature Sensing (DTS) systems. The company creates and supplies a broad variety of fiber optic solutions for monitoring worldwide. If you are interested in temperature measurement systems and want to learn more, please contact us at info@optromix.com

New Distributed Temperature Sensing allows fast oil extraction

DTS for oil extractionThe traditional methods of oil extraction become less and less productive despite growing human needs. Today the main challenge of the oil industry is the development of a new way for oil recovering from unconventional sources. The solution is the extraction of oil or kerogen shales that allow diminishing oil prices.

It is possible, because of the distributed temperature sensing (DTS) method that uses optical fiber cables, however, DTS with optical fibers using polymeric coatings becomes not efficient at temperatures exceeding 300°C, but optical fibers coated in gold withstand the temperature.

 

A conventional way of oil extraction includes drilling a well into a location underground, where oil flows freely from a reservoir. Also, oil can be removed using non-traditional methods. Thus, unconventional oils, for example, oil shale, are becoming more economically and technically accessible techniques thanks to absolutely new modern technologies.

Distributed temperature sensing becomes the main tool for unconventional oil recovering that makes the process more efficient with advanced methods, such as the measurement of the whole well system temperature. To be precise, it is possible for DTS to monitor the temperature at several points along the well, where optical fibers are used as the temperature sensor element.

Since the majority of DTS systems use optical fibers covered with polymeric coatings, their use is limited for temperatures up to 300 °C, because the fiber life expectancy is gradually reducing.

Such high temperatures of 350 °C are necessary for kerogen to oil conversion. So new distributed temperature sensing with optical fibers coated in gold is able to stand temperatures as high as 700 °C and identify hot spots that are highly important to regulating in-ground systems.

 

One of the main aims of the new DTS program is the actual well temperatures measurement. Moreover, continuously monitoring well temperatures is crucial for precisely controlling the amount and rate of heat applied because finally, this estimates the amount of oil that will be extracted at the time of the in-situ retort process.

Also distributed temperature sensor systems are used in numerous fields, for example, power cable monitoring, fire detection, leakage detection, industrial induction furnace surveillance, pipelines integrity surveillance, healthcare and biomedicine areas, etc. Nevertheless, the use of DTS systems in oil and gas production is the main factor driving the growth of the DTS market.   

Optromix is a DTS system manufacturer that provides top of the line distributed temperature sensing systems suitable for monitoring the underground power cable temperature profile. If you have any questions or would like to buy a DTS system, please contact us at info@optromix.com

Distributed Sensing Technology for Different Types of Power Cable Monitoring

DTS for power cable monitoringDistributed sensing technology includes distributed temperature sensing, distributed acoustic sensing, and to a lesser degree distributed strain monitoring. Distributed sensing technology has been prevalent in the power and utility sector since the 1980s and the largest area where this technology is commonly used is in the power cabling monitoring. Due to the evaluation of the technology most power cable condition monitoring applications have historically been associated with distributed temperature sensing, but nowadays engineers and scientists are increasingly using distributed acoustic sensing in different applications.

The applications for distributed temperature sensing in power cable monitoring includes:

  • Real-time thermal rating of cables (also known as dynamic cable rating). This has primarily been for buried cables, subsea cables, and cable tunnels, but they’re also have been applications for overhead cables;
  • Hotspot detection;
  • Fire detection for cables.

One of the key factors in the configuration of the distributed temperature sensing systems has been the position of the fiber optic sensing cable in relation to the power cable. At its best, the DTS fiber optic sensing element would be located within the construction of the power cable itself. However, in many cases, the DTS fiber sensing element is attached to the surface of the power cable configuration (or in the vicinity), because of cable construction design or installation issues around splice joints.

There are various areas, types of cables, and applications covered by distributed sensing technology including:

  1. Buried (underground) cable monitoring;
  2. Tunnel cable monitoring;

 

  1. Subsea power cable monitoring (subsea cables are difficult to access and expensive to repair);
  2. Overhead cable monitoring.

Power cable links can be critical assets in project commercial liabilities. Power links, for example, are used to energize offshore installation in the oil and gas pipeline monitoring market. Outages have tangible commercial implications, so that project risks are managed more effectively through better asset life management.

Optromix is a fast-growing seller of such products from the fiber Bragg grating (FBG) line of products: fiber Bragg grating sensors, FBG interrogators, and multiplexers and, of course, Distributed Temperature, Acoustic, and Strain Sensing systems (DTS). Our major goal is to deliver the best quality of fiber optic sensors to our clients. Optromix creates and supplies a broad variety of excellent fiber-optic solutions for the monitoring of various facilities all over the world.

If you would like to purchase Distributed Temperature (DTS), Distributed Acoustic (DAS), or Distributed Strain systems, please contact us: info@optromix.com

 

Distributed Temperature Sensing systems: Benefits and Applications

Distributed Temperature SensingOne of the most promising directions in the development of systems for controlling of temperature of high-voltage power lines, fire alarm systems, oil and gas fields, and others are DTS systems. Distributed Temperature Sensing Systems is a rising technology which will be further actively developed in the near future. According to the forecasts, the price of such fiber-optic DTS systems will continue to decline while the productivity of them will continue to increase. Distributed Temperature Sensing technology becomes more applicable and more popular for many applications in a wide range of industries.

DTS systems were actively involved in various areas of scientific and engineering developments since the 1980s as temperature systems which can measure temperature with a high degree of accuracy over significant distances. In addition to this, such optoelectronic systems were able to provide a continuous profile of the temperature distribution along the fiber-optic cable or other devices. The main measuring principles were based on detecting the back-scattering of light using the Rayleigh, Raman, and Brillouin principles.

The key to the understanding of fiber-optic Distributed Temperature Sensing systems is awareness of the fact that the optical fiber itself is the sensor and the instrumentation provides measurements on every 1m along the length of the fiber. What does this mean? This means that the operator is able to receive temperature information at all points from the moment of cable installation. Real advantages of DTS systems become apparent when a temperature profile of the installation is required or when a large number of sensing points is crucial. DTS systems are much more convenient than any conventional temperature sensing technology.

Distributed Temperature Sensing technology becomes practical for many applications. For instance, one of the most promising technologies based on the DTS principle is linear optical fire detection. Such fire detection allows us to detect fire and localize the seat of the fire within a building with 1m resolution. Also, DTS systems are applied, for instance, in the oil and gas industry. The systems in question are used to monitor the temperature log of the well. In addition to this, fiber-optic DTS systems provide an opportunity to upscale the measurements to large spatial extents and monitor the temporal dynamics of the hydrological processes. Recent enhancements of this technology based on distributed sensing systems have allowed the balance of energy and fluid mass at a watershed scale. However, it is difficult to say that about all cases of DTS application. These systems are involved in the power systems, in cables for better ampacity judgment and in safety applications like the mines are reviewed. So it is not surprising that the number of companies providing DTS systems is growing ever so much.

Optromix is a fast-growing seller of such products from the fiber Bragg grating (FBG) line of products: fiber Bragg grating sensors, FBG interrogators and multiplexers, and, of course, Distributed Temperature Sensing Systems (DTS). Our major goal is to deliver the best quality of fiber-optic sensors to our clients. Optromix creates and supplies a broad variety of excellent fiber-optic solutions for the monitoring of various facilities all over the world.

If you would like to purchase DTS (Distributed Temperature System), please contact us: info@optromix.com

Fiber Bragg grating sensors in for the monitoring of storage nuclear fuel pools

FBG sensors for nuclear fuel monitoringRecent events in the nuclear industry have shown the weaknesses in the control of the critical systems that ensure the safety of the nuclear plant. The extreme and accidental conditions, such as high temperatures and high levels of radiation sabotage the security of nuclear power plants, leading to major disasters. The main issue for the nuclear industry is to enhance the security of existing nuclear power plants and improve the design of the future ones. In the case of emergency or accidental conditions in nuclear reactors the following thermodynamic parameters need to be known in order to facilitate appropriate actions: temperature, pressure, water level, radiation level. The accuracy of the obtained information directly influences the decisions made by the operators. The monitoring instruments used inside the nuclear fuel pools need to better withstand severe conditions that occur during malfunctions and accidents, namely high temperatures and high levels of radiation. The strict safety regulations have pushed the fiber optic market to develop sensors based on optical fibers. Optical fiber sensors, like FBG sensors and DTS systems, have attracted interest from the nuclear plant industry for their ability to withstand harsh conditions.

Optical fiber properties depend on the temperature, strain, pressure, etc., therefore the fiber itself can be used as a sensitive element of the sensor. FBG sensors have been tested in various harsh environments and have shown consistent resistance to various harsh conditions. The immunity of FBG sensors to high temperatures, high levels of radiation, electromagnetic influence makes them an ideal monitoring solution for nuclear power plants. FBG sensors are easily mounted on any surface, are cost-effective, and require low maintenance.

There are several types of FBG sensor types that are designed to measure specific parameters. FBG temperature sensors provide long-range, long-term deployments, have a long reliability period, and have a compact size. FBG temperature sensors also provide the fastest response rate, which is especially important for emergencies and accidents.

Fiber Bragg grating (FBG) pressure sensors perform spectral analysis of the reflected wavelength to measure different parameters. Like all fiber optic sensors, FBG pressure sensors are compact and portable. FBG pressure sensors can measure high-speed events, which is essential for the localization of malfunctions inside the nuclear fuel pots.

The ability to withstand harsh conditions is the most attractive quality of FBG sensors. The use of sensors based on fiber optic technology has the potential to significantly increase the security of nuclear power plants.

Optromix is a fiber Bragg grating (FBG) sensor, vendor. We create advanced fiber optic technologies and our client’s satisfaction is our top priority. We deliver cutting-edge hi-tech products, yet we offer competitive pricing and rapid delivery time. If you want to purchase FBG temperature sensors, FBG pressure sensors, please contact us at info@optromix.com

Distributed temperature sensing (DTS) in geothermal energy applications

DTS in geothermal energy applicationsTraditionally, geothermal plants have been located in areas where hot springs and other indicators of thermal activity can be seen at the surface. However, enhanced geothermal systems (EGS) may also be used in areas where hot rock is found at reasonable depths. To achieve geothermal energy, fluid is injected into the drilled wells, heated by contact with the hot rock, and removed to power turbines at the surface. The majority of EGS utilize steam turbines to convert geothermal energy into electricity.
Under the constant pressures to lower operational costs and raise the effectiveness of the EGS, a number of parameters need to be managed to ensure high efficiency and competitive electricity prices. The efficiency of a geothermal plant is entirely reliant on the amount of steam that can be retrieved from the well, therefore, the subsurface reservoir must be able to provide quality geothermal fluid in sufficient quantities over its service life.
In order to retain the needed pressure in the well and to extend its service life, geothermal fluid achieved by hydraulically fracturing the hot rock is re-injected. Consequently, it is crucial to understand where the fluid is going inside the well and where the fluids come from.
It is well known and documented that the use of distributed temperature sensing in geothermal energy applications has greatly improved the reliability and longevity of EGS. Distributed temperature sensing systems can also be combined with other sensors, like FBG pressure sensors, to provide a complete data set. The information – subsurface temperature and pressure – can be used in various ways, such as:
1. Estimation of the production potential in the new wells be measuring the temperature at the point of pressure
The rate at which the fluid pressure drops after the operator opens the tap at the surface allows the calculations of reservoir size, flow resistance between wells, well completion, etc.
2. Monitoring of the surface and subsurface scale buildup and chemical cleanup
The buildup of scale – a mineral residue precipitated from the geothermal fluid – can inhibit fluid flow and block a pipe. A better understanding of the severity of the scaling may improve the choice of mitigating options.
3. Integrity monitoring for casing and tubing leaks.
The compromised integrity of the casing and tubing may lead to contamination of ground and subsurface aquifers.
An installed DTS system provides many additional monitoring opportunities. The efficiency of the geothermal plants may be greatly improved by combining temperature data with subsurface point pressure data. Distributed temperature sensing channels may be added to monitor surface processes. Another geothermal energy application of DTS systems in localization of overheated areas that allows mitigating the hotspots.
If you would like to purchase DTS (Distributed Temperature System), please contact us: info@optromix.com or +1 617 558 98 58

Real Time Thermal Rating systems

RTTR, or Real-Time Thermal Rating, is a method of assessing real-time operational thermal rating of the equipment, or the amount of electrical current that a power line or an electrical facility can endure before suffering critical damage. Thermal rating devices can be used to measure the temperature of overhead power lines, transformers, underground and subsea cables.

Real-time thermal rating systems rely on real-time data from environmental conditions rather than theoretical assumptions and predictions. These systems are able to not only measure the thermal ratings in real-time but also to measure the stress levels of certain areas and determine their capacity. The calculation of the thermal ratings happen on the basis of: 1) weather conditions; 2) electrical current; 3) temperature of the equipment. However, other factors may need to be considered; this depends on the environment where real-time thermal rating needs to be performed. For example, soil condition, burial depth, and configuration must be considered for temperature measurement of underground cables, the mass of the transformer and type of the cooling mechanisms for temperature measurement of transformers, etc.

The key to the real-time thermal rating system, the temperature of the asset, should be continuously measured to avoid heating of the asset to dangerous levels. Distributed temperature sensing (DTS) systems should be used for this purpose, otherwise, only predictions about the temperature can be made.

The main advantage of real-time thermal rating systems is their ability to accurately measure the thermal behavior of assets, taking into consideration factors that static ratings do not. Static rating calculations are often overly conservative, therefore some power lines are often not used up to their full potential, while others are overloaded, which causes premature aging.

Thermal rating systems may be implemented into different types of power assets. Underground cable monitoring benefits greatly from introducing real-time thermal rating systems as they measure soil ambient temperature and soil thermal resistivity; these measurements help to determine actual thermal headroom to indicate unused network capacity.  

The thermal rating of the overhead power lines, depending on the actual system used, takes either the sag of the lines, the tension of the line conductor, the temperature of the line conductor, or environmental conditions into account during calculation.

Transformer load, ambient and transformer temperatures, oil temperature, and winding hot spot temperature are utilized by RTTR systems for transformers.

DTS optic sensing fibers are important for real-time thermal rating; they are installed along the length of the power cable and provide a continuous temperature profile.

If you would like to purchase DTS (Distributed Temperature System), please contact us: info@optromix.com or +1 617 558 98 58.