Distributed Temperature Sensing has drawn high attention at the Jicable 2011 Conference in Versailles, France

Distributed Temperature Sensing (DTS) Systems for high voltage cable systems were frequently discussed in course of the recent Jicable conference, the 8^th International Conference on Power Insulated Cables.

Several papers on online condition monitoring based on fibre optic temperature sensing were presented. In more papers DTS was mentioned as being part of the high voltage cable project discussed.

 

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The necessity analysis of distributed fiber-optic temperature monitoring by Xiamen power cable alarm case study YAN Youxiang, SU Xueyuan – Xiamen power Ultility, Xiamen, Fujian; China XIAO Chuanqiang – SINDIA, Beijing; China

Dynamic rating of transmission cables
Erik JACOBSEN, Jonas Fabricius NIELSEN, Steen Beck NIELSEN – SEAS-NVE Holding, Haslev; Denmark Sven SALWIN – nkt cables A/S, Copenhagen; Denmark Karl-Heinz COHNEN, Andreas MOHRS – nkt cables GmbH, Köln; Germany

Real time load optimisation of cable based transmission grids Rasmus Schmidt OLSEN, Unnur Stella GUDMUNDSDÓTTIR – Energinet.dk, Fredericia; Denmark Joachim HOLBOELL – Technical University of Denmark, Kongens Lyngby; Denmark

Read more about Jicable in general:

June 2011 Versailles Congress Centre – Jicable’11 – 8^th International Conference on Power Insulated Cables

What is Jicable’11?
Jicable ’11 is an international forum for the exchange of information in the fields of research, industrial development, installation, operation and diagnoses relating to insulated power cables and their accessories from low voltage and special cables up to ultra high voltage cables and cables of new technologies.

Why is Jicable’11 important?

Insulated power cables are increasingly used in electrical power transmission and distribution networks. This is due to the significant progress achieved in the development of new technologies with higher performances, and supported by increasing environmental pressure. Cables are recognised as a reliable means for the transportation and distribution of electrical energy. Jicable’11 will allow in-depth analysis of the State-of-the-Art and future perspectives : new materials, evolution in technologies, improvements in fabrication process, improvement of maintenance policies and remaining life estimation, lessons learned from service experience, dielectric phenomena, thermal and thermo-mechanical behaviour, new innovative technical solutions for high power transmission : new superconductive materials as well as a closer look at major submarine cable projects connecting High Voltage networks in many countries.

Who will be taking part in Jicable’11?

As in past Jicable conferences held in 1984, 1987, 1991, 1995, 1999, 2003 and 2007 (581 delegates from 48 countries), Jicable’11 will prove very useful to the following segments of the cable industry : researchers, engineers, decision-makers, raw materials suppliers, manufacturers, consultants, installers and users.

The following topics will be discussed:

• LV and MV Cables Systems
• HV and EHV Cables Systems
• Submarine Cables
• Economy and costs of Cable Systems
• Ageing, Diagnosis, Maintenance, Remaining Life Estimation and Management
• Cables for the Future
• Technical challenges encountered with cable systems
• Industrial and Special Cables
• Cables, environment and sustainable development
• Design
• Testing Methods

Jicable 2011 was organized with the support of:

• S.E.E. – Société de l’Électricité, de l’Électronique et des Technologies de l’Information et de la Communication
• CIGRÉ - International Council on Large Electric Systems
• ERDF – Électricité Réseau Distribution France
• RTE – Réseau de Transport d’Électricité
• SYCABEL – Syndicat Professionnel des Fabricants de Fils et Câbles Électriques
• SERCE – Syndicat des Entreprises de Génie Électrique et Climatique

The Jicable’s Booklet

Discover the Jicable’s Booklet which contains all practical information about Jicable including registration procedures and technical programme

Download the Jicable’s Booklet

LIOS 10 Years Anniversary Celebration Held in Paris

Thanks for joining us in Paris for the festive 10 years anniversary celebration of LIOS Technology in the industry. We at LIOS Technology would like to thank you for your continuous interest in our products throughout the recent years.

The CIGRE 2010 Session – International Council on Large Electric Systems – was once again an impressive industry gathering of international experts for electrical high voltage systems. It was the ideal platform for LIOS to celebrate its company anniversary as many loyal friends and partners were already in town.

LIOS Technology has chosen the historic cave system of Les Crayères des Montquartiers for its evening function which offers festive and cosy atmosphere but also bridging to LIOS company launch with its successes in fire detection systems for tunnels.

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Pipeline Monitoring – Locating leakages at oil and gas pipelines

Leaks occurring in underground pipelines constitute a substantial danger for both, human beings and the environment. Oil escaping from pipelines pollutes the earth and ground water.

Leaking gas creates the danger of fires and explosions. In addition, leaks bring about large economic losses. It is extremely important to locate leaks as soon as they occur and to be able to locate small leaks. Until now, monitoring systems have only reacted to large leaks and have not been able to pinpoint them accurately. Oil leaks cause temperature anomalies below the pipeline, whereas escaping gas induces a temperature decrease above the pipeline due to the easing of pressure.

Efficient leak location and the long-term monitoring of gas and oil pipelines can therefore be achieved by measuring the temperatures along a pipeline and observing how these temperatures vary over time. Optical-fibre, temperature-measuring technology presents new opportunities in this connection.

An optical-fibre, temperature-measuring cable is laid along a pipeline, enabling the temperatures in the ground to be measured simultaneously over long pipeline distances with a high degree of locational accuracy.

The sensor cable is completely passive electrically and can therefore by fitted to pipelines where a high risk of explosions exists.

The leakage-location principle by means of optical-fibre, temperature-measuring technology

LIOS Leakage Detection for Oil Pipelines

LIOS Leakage Detection for Gas Pipelines

Using optical-fibre, temperature measuring to monitor pipelines makes possible:

• The economical location of leakages and the long-term monitoring of pipelines

• The monitoring of pipeline sections up to 30 km long by means of a system

• The opportunity of linking individual systems to form an overall system to monitor longer sections if necessary

• The quantifying of leakage rates using model calculations

• It is not necessary to empty and clean the pipeline before inspecting it

• Shutting-down the pipeline is not necessary

• Small quantities of escaping oil can be exactly detected and located

• Damage can be identified in its early stages

The measuring system enables the temperature along a section of pipeline to be measured by using optical-fibre sensors. Temperature anomalies caused by leakages are identified via this system and the efficient location of leakages and long-term monitoring of gas and oil pipelines are thus made possible.

Read more:

• Distributed Temperature Sensing
• LNG and LPG Containment Integrity Monitoring Solutions

температурный мониторинг: Надежность и безопасность электросетей под постоянным контролем

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Один из способов обеспечения надежной работы кабельной системы в городских условиях — это мониторинг температуры фаз кабеля по всей длине. Необходимость применения системы мониторинга распределенной температуры КЛ, подтверждается опытом западных коллег и требованиями к эксплуатации КЛ в современных мегаполисах.

Такая система помогает эксплуатационным организациям в решении
следующих задач:

• снижение количества перебоев в электроснабжении или системных аварий;
• оперативное реагирование на возникающие перегрузки;
• выявление скрытых резервов существующих мощностей (увеличение нагрузки без превышения допустимой температуры)
• прогнозирование срока эксплуатации и др.

Пропускная способность кабеля ограничивается допустимой температурой нагрева жилы. Однако влияние на рабочие показатели системы ока

зывают и другие факторы, такие как условия прокладки (тепловое сопротивление грунта, температура грунта, расстояние до соседних кабелей и других источников тепла, находящиеся поблизости и т.д.). На разных участках трассы при протекании одного и того же тока, температура токопроводящей жилы может отличаться. Ключевым элементом современных систем распределенного измерения температуры кабеля стало оптическое волокно.

«КАБЕЛЬ-news», март 2010

Читать подробнее:

• Инновационная система комплексной диагностики КЛ
• Смотреть видео: Инновационная система комплексной диагностики КЛ / Распределительный сетевой комплекс: состояние, проблемы, пути решения

Russia Ready for Modernising its Electrical Distribution Network – Global Condition Monitoring Presented at MRSK Conference

MRSK Holding (internationally also known as JSC “IDGC Holding” – Interregional Distribution Grid Companies Holding) organised a well attended conference focusing on status, problems and solutions of the electrical distribution network of Russia which was collocated to the 17th International Specialized Exhibition “Energetika + Elektrotechnika  – 2010” on power and electrical engineering taking place in Saint Petersburg, Russia from 11 – 14 May 2010.

The conference initiated by MRSK Holding was officially supported by the Ministry of Economic Development and Trade of the Russian Federation, Ministry of Power Industry of the Russian Federation, Saint-Petersburg Government, the Government of the Leningrad region, Legislative Court of the Leningrad region and the Regional Office of the  Federal Energy Agency in the North-West federal region and attended by over 400 people.

Among them, high ranking management representatives of Russian grid operators and companies involved in the energy sector as well as from major international companies like EDF, ERDF, Schneider Electric and Nexans.

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In total 13 technical reports were presented in front of chief engineers and technical specialists of MRSK’s operating subsidiaries covering the broad scope from the current status of the Russian distribution network with its challenging tasks up to innovative solutions for modern asset management of the grid of the future.

LIOS Technology and its Russian partner Systec Cables were proud to be part of this honourable event and in the position to present its Global Condition Monitoring System – a comprehensive “health package” for the online assessment of critical operation factors like thermal load and partial discharge levels along the electrical grid structure. The presented solution provides answers for save and most efficient grid operation. This complemented combination of DTS and PD solutions provides grid owners an even better control and monitoring possibility of their grids. Together withReal Time Thermal Rating (RTTR), a platform has been created for a complete scope of condition assessment, control, monitoring and ampacity predictions.

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The key note of the presentation by LIOS and Systec to aim for maximising the grid availability and condition based maintenance was in line with a statement by the MRSK’s head of technical development and management Dmitry Medvedev at this conference who said that one of the main requirements for a modern electric grid equipment is the mandatory use of new technologies in order to reduce unit costs and improve performance of network elements.

Read more:

• Distributed temperature monitoring of power cables
• Watch video / Смотреть видео: Инновационная система комплексной диагностики КЛ
• Конференция Холдинга МРСК
• Конференция «Распределительный сетевой комплекс России: состояние, проблемы, пути решения» может стать ежегодной
• «Энергетика и Электротехника» в павильоне №7, 8А выставочного комплекса «Ленэкспо» (г. Санкт-Петербург)
• Инновационная система комплексной диагностики КЛ
• Распределительный сетевой комплекс РФ: состояние, проблемы, пути решения

An Introduction to Distributed Temperature Sensing

Distributed Temperature Sensing Systems (DTS) are optoelectronic devices which measure temperatures by means of optical fibres functioning as linear sensors. Temperatures are recorded along the optical sensor cable, thus not at points, but as a continuous profile. A high accuracy of temperature determination is achieved over great distances.

Measuring Principle – Raman Effect
Physical measurement dimensions, such as temperature or pressure and tensile forces, can affect glass fibres and locally change the characteristics of light transmission in the fibre. As a result of the attenuation of the light in the quartz glass fibres through scattering, the location of an external physical effect can be determined so that the optical fibre can be employed as a linear sensor.

Optical fibres are made from doped quartz glass. Quartz glass is a form of silicon dioxide (SiO2) with amorphous solid structure. Thermal effects induce lattice oscillations within the solid. When light falls onto these thermally excited molecular oscillations, an interaction occurs between the light particles (photons) and the electrons of the molecule. Light scattering, also known as Raman scattering, occurs in the optical fibre. Unlike incident light, this scattered light undergoes a spectral shift by an amount equivalent to the resonance frequency of the lattice oscillation.

The light scattered back from the fibre optic therefore contains three different spectral shares:

• the Rayleigh scattering with the wavelength of the laser source used,
• the Stokes line components with the higher wavelength in which photons are generated, and
• the Anti-Stokes line components with a lower wavelength than the Rayleigh scattering, in which photons are destroyed.

The intensity of the so-called Anti-Stokes band is temperature-dependent, while the so-called Stokes band is practically independent of temperature. The local temperature of the optical fibre is derived from the ratio of the Anti-Stokes and Stokes light intensities.

Measuring Principle – OFDR Technology
Latest DTS evaluation units deploy the method of Optical Frequency Domain Reflectometry (OFDR) .  The OFDR system provides information on the local characteristic when the backscatter signal detected during the entire measurement time is measured as a function of frequency in a complex fashion, and then subjected to Fourier transformation. The essential benefits of OFDR technology are the quasi continuous wave mode employed by the laser and the narrow-band detection of the optical back scatter signal, whereby a significantly higher signal to noise ratio is achieved than with conventional pulse technology (OTDR). This technical benefit allows the use of affordable semiconductor laser diodes and electronic assemblies for signal averaging.

The optical frequency domain reflectometry has been developed as a high-resolution measurement process for the characterisation of optical wave guides with length dimensions of just a few millimetres. In contrast, its application for the Raman backscatter measurement was introduced and patented by the company LIOS Technology.

Schematic system set up
The temperature measuring system consists of a controller (frequency generator, laser source, optical module, HF mixer, receiver and micro-processor unit) and a quartz glass fibre (fibre optic) as line-shaped temperature sensor.

The design is three-channel, since an additional reference channel is required besides the two measurement channels (Anti-Stokes and Stokes). Corresponding to the OFDR system, the power output of the laser runs through the sinus-shaped frequency starting from a starting frequency in the kilohertz range through the ending frequency in the high megahertz range within a measurement time interval with the help of the High Frequency (HF) modulator. The resulting frequency shift is a direct measurement of the local resolution of the reflectometer. The frequency-modulated laser light is connected to the fibre optic-sensor via the optical module.

The continuously back-scattered Raman light  is spectrally filtered  in the optical module and converted into electrical signals by means of photo detectors. Then the measurement signals are amplified and mixed in the Low Frequency spectral range (LF range). The Fourier transformation of the averaged LF signals results in the two Raman backscatter curves. The amplitudes of these backscatter curves are proportional to the intensity of the Raman scattering of the viewed location. The fibre temperature along the sensor cable results from the amplitude ratio of the two measurement channels.

The ideal DTS sensor embedded in power cables: Fiber In Metal Tube (FIMT)

The optical fiber serves as the distributed temperature sensor for LIOS DTS systems and is typically surrounded by a protective layer. It is preferably encased in a stainless steel tube which significantly increases the mechanical stability of the sensor. Fibre encapsulated in stainless steel tube or short “Fiber In Metal Tube (FIMT)” is a hermetically sealed rugged construction for very long lengths of optical fibres. Furthermore, it is particularly effective in protecting against the hydrostatic pressures, high temperature effects and corrosive environments.

The inside of the FIMT metallic tube may lined with gel to ensure that the sensor cable remains permanently water-proof. This viscous gel protects the fibres from many environmental concerns, prevents damage from microbending conditions and helps to minimize the forces applied during spooling and deployment.
An important parameter to consider with FIMT is the Excess Fiber Length. It is defined by the percentage of excess fiber loaded into the metal tube during processing to relieve induced stresses directly related to the differing thermal coefficient of expansions of each material contained in the construction. FIMT is exposed to drastic and often rapid changes in temperature and pressure, so the Excess Fiber Length must be considered to ensure continuous, robust performance across all operational conditions.

FIMT constructions contain individual or multiple fibers (single mode or multi mode) and are available in sizes ranging from 1 mm to 3 mm outer diameter, variations in effective wall thickness are possible as well. FIMT serves as the core for various fiber optic sensor cable constructions or may be integrated into high voltage cable designs directly.

The FIMT is manufactured from a special stainless steel strip. During the manufacturing process this strip is formed to a tube and welded along its length. The stainless steel tubes must be hermetically sealed for all applications. For this reason the complete weld seam is subjected to a leak proof test by means of eddy current. By means of a drawing process the desired final diameter is attained on the one hand and an increase in strength through cold conversion on the other. During the manufacturing process the optical fibers are inserted into the tube. They are clearly differentiated by means of a specific colour code. At the end of the production process the tubes are subjected to a complete optical attenuation measurement and then documented for back-tracing. Additionally, each length produced is subjected to a weld penetration test, each weld seam undergoes a leak test, and the Excess Fiber Length is checked.

LIOS offers a variety of FIMT constructions perfectly suitable for distributed temperature sensing applications along power cable transmission systems.

Superior Technology and Industrial Strength – State of the Art DTS Production

The LIOS’ DTS (Distributed Temperature Sensing) technology has been successfully proven in critical applications like fire detection in road and rail tunnels,  power cable and transmission line monitoring, in oil & gas exploration for permanent downhole monitoring and for industrial induction furnaces surveillance, where these systems have been equipped in worldwide projects with more than 2000 permanent installations since 1997.

Key advantages of Raman OFDR distributed temperature sensing (DTS) systems by LIOS Technology:

• Reliable system design with approved key components from the telecom industry
• The OFDR technology enables to provide sophisticated temperature surveillance at commodity prices
• Invariant spatial resolution along the entire sensor length of 1 m or 50 cm even at most remote distances.
• Direct link to SCADA systems and flexible data handling
• International Approvals and Certificates – type tested and accredited
• Impressive track record of more than 2000 installations in permanent operation

At LIOS’ new facilities at Seiler Höfe, Cologne, Germany we experience ideal surrounding conditions as an industrial manufacturer of fiber optic DTS sensor systems. In conscious of the strong requirements being made in the safety market, we provide a highly proven product based on the compliance with international quality standards recognised by impartial and competent partners for type testing our products like the VdS (Association of German Property Insurers), Deloitte or EXAM and is furthermore reflected in our implemented quality management system, certified according to DIN ISO 9001 / Edition 12/2008 and our environmental management system according to ISO 14001.

• Industrial DTS production with impressive track record
• Modern and efficient production procedures
• Comprehensively type tested
• 100 % applied Factory Acceptance Test (FAT)
• Customised Site Acceptance Test (SAT) through experienced staff on site
• High Tech made in Germany

LIOS DTS production facilities in Cologne, Germany

LIOS DTS production facilities in Cologne, Germany

Assembly and testing site for LIOS DTS systems

LIOS DTS Factory Acceptance Test (FAT): data recording and test bench

Related information on LIOS DTS technology:

• The technology behind LIOS OFDR distributed temperature sensing systems

Setting Standards for Highly Reliable DTS Performance

LIOS Technology GmbH is the leading manufacturer of industrial DTS systems with an impressive track record of more than 2000 installations in permanent operation. Its current DTS product series was carefully designed and thoroughly tested targeting reliable performance and smooth operation in industrial environments.
This was imposingly endorsed by the latest statistical field analysis in respect of a mean time between failures (MTBF) evaluation. Adapted from field data of our installed base of the current DTS product series an excellent MTBF figure of 28 years was reached.

High reliability is also a result of the unique optical frequency-domain reflectometry (OFDR) technology of the LIOS DTS systems. In contrast to time-domain technology using pulsed lasers with high peak powers, the LIOS OFDR DTS uses a quasi-continuous laser with low peak power resulting in a nonexistent wear out of the laser unit or any other fatigue of other optical components. The exceptional reliability favors the deployment of the LIOS DTS systems in all remote, safety-relevant and industrial applications.

Offshore Europe 2009 – Meet us in Aberdeen – 8-11 September 2009

LIOS Technology will be exhibiting at Offshore Europe 2009, from 8 till 11 September in Aberdeen, German Pavilion. In this show, we proudly present our full range and latest Distributed Temperature Sensing (DTS) systems for Oil & Gas applications.

See the latest information about our new HT SAGD application (high temperature steam assisted gravity drainage) for Oil & Gas including our new hydrogen resistant fibre rated 300 degree C and our latest auto calibration system.

Please contact us directly at oil@downhole-monitoring.com for more information or to make an appointment.

Visitors are invited to stop by the LIOS stand  No. 1397 b.
LIOS staff will be on hand to answer questions and discuss particular challenges.

Please register for free admission at  http://www.offshore-europe.co.uk/LIOSTechnology

Read more at our  Downhole Monitoring website.