Distributed Temperature Sensor - Capabilities

Hans Meulman Business Development Manager Optical Fiber Sensing Solutions Yokogawa Europe

DTS Basics

Backscattered

Introduction DTS technology

The fiber optic Distributed Temperature Sensing (DTS) method using the Raman-effect has been developed at Southampton University in England, UK in the early 80’s.

The DTS method is based on Optical Time-Domain Reflectometer (OTDR) technology and uses a technique derived from telecommunication cable testing.

The fiber optic-based DTS method measures temperature using optical fiber instead of thermocouples or thermistors

Distributed Temperature Sensor (DTS)

Principle Measurement

T1 T2 T3 T4 ……….

DTS Instrument (interrogator)

Distributed Measurement - 1m spatial resolution

Measurement of 50 km – Optical fiber = 50,000 sensors!

Backscattered light provides temperature at every 1m

Standard multi-mode optical fiber

Distributed Temperature Sensor (DTS)

Backscattered light

laser

detection

laser pulse

Optical fiber Scattered light spectrum

Temperature dependent

Raman Anti-Stokes

Raman Stokes

Frequency shift

Spectrum Principle

Light is backscattered from natural anomalies within the fiber

This happens at all points within the fiber

Range gating allows specific sections along the fiber’s length to be examined

DTS Measurement Principle

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Spectrum Principle

DTS Applications

Borehole Heel

Temperature Monitor (Steam Chest formation, Breakthrough)

Flow Monitor (Joule-Thomson Effect) (Oil or Gas Flow at each Zone)

Steam Oil

Applications: Downhole Applications

LNG Terminals

LNG Tanker

LNG Tank Vaporizer Governor

Gas Tank

Offloading Pipe Initial Cool Down Monitoring and Leak Detection Reducing Start Up time Preventing Gas Leak

Bottom of Tank Temperature Monitoring Preventing Ground Freezing

Pipe Leak Detection Preventing Gas Leak

Applications: LNG

Inner Tank

Outer Tank

Detecting the leakage

Optical Fiber Cable

DTS can identify small leakage

Applications: LNG Tank leak detection

10

Applications: Monitoring power lines

Monitoring of power transmission line temperature

To check abnormal hot-spot (ground fault, insulation breakdown etc.)

To predict temperature of conductor from cable temperature and current.

Overheating of cable’s maximum operating temperature

Quick detection of small leakage events and monitoring of the pipeline temperature profile.

Pipelines such as LNG, LPG, ammonia, ethylene create cold zones which can be easily detected when leaks occur.

Applications: Pipeline Leak Detection

Customer benefits

No Blank Area: Only one optic fiber can monitor temperature for wide area

Prompt Action: Heated Location Detection in short time (<10sec/Channel)

Full overview: With the optical fibre you can monitor a big area. Give warning what avoid damage on the installation

Applications: Hot Spot Monitoring

Applications: Fire detection in Conveyor systems

Rollers

Belts

1

2 2’

3 3’

4

Optical Sensor Cables

Application

Detection of heat build-up/fire along industrial conveyor systems prior to fire outbreak (woodchips)

DTS detects abnormal temperature at every point of the conveyer.

Applications: Fire Detection for Cable rack system

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Application

Detection of heat build-up/fire in cable tray or rack system

Customer benefits

No Dead spot: Only one optic fiber can monitor temperature along the cables.

Monitoring Wide Area: Multi Channel Monitoring by using Optical Switch

Prompt Action: Heated Location Detection in short time (<10sec/Ch.)

Much more:

– Industrial Facilities

– Tunnels

– Structures & Buildings

– Environments Monitoring

– Dams

– Dykes, Waterways and Harbours

Applications ……..

Fiber optical cable

Advantage of the Optical Fiber Cable

Immunity to electromagnetic interference (EMI) and electrical discharge (lightning)

Passive operation, intrinsically safe.

Water and corrosion resistant

Excellent resolution and range

Rugged, small size and light weight

Absolute measurement

Low signal loss, sensors may be interrogated for many kilometres

Signal conditioning equipment has much smaller foot print

Fiber Cable The sensor

DTSX Unit

DTSX Modules

DTSX Performance

Spatial Resolution: 1m

Sampling Interval: 10cm, 20cm, 50cm, 1m

Temperature resolution: 0.2 ℃ (3km, 10min) (DTSX200)

Temperature resolution: 0.03℃ (10Km , 10min ) (DTSX3000)

Non-Volatile on-board Memory data storgae (100 traces)

Low Power Consumpotion (full operating Range)

Operation 10W, Standy-by 2W (DTSX200)

Operation 16W, Standy-by 2W (DTSX3000)

Performance Specifications

DTSX Lineup

19 inch compact rack design

Industrial design -40 to +65°C (2 & 4 ch)

Humidity 20-80% RH. Non-condensing

Low weight and footprint (weight 2,5 kg)

Compact Industrial Design

Approvals Compliance

ATEX Type ”n”

CSA Type ”n”

FM : Class I, Div 2, Gps A, B, C, D T4

CSA : Class I, Div 2, Gps A, B, C, D T4

DTSX Modular design

Alarm Management Integrated

Full Alarm management Module inside

30 alarm section to define

Combination of differed alarm types

Alarms available in Process environment

Fully Integrated in DTSX

Alarm Section

High, Low, Rise, Fall & Difference

Integrate Programmable Logic Controller

STARDOM PLC: Programmable Logic Controller

– Control with programmable logic

– Simple or Sequential Process

– Interface with DTSX (Tempurature data & alarm data)

– Embedded I/O

Openness Integrated PLC

Temperature Info

Pressure, flow, temperature relay, buttons indicators….

Conclusion

Advantage of DTS

When there are a large number of sensors to be placed

A single optical fiber can replace many point sensors

When there is no a priori knowledge of sensor placement

Not always possible to determine the correct location/position for temperature sensor

When electrical temperature monitoring is impractical

Situation where there is a large amount of electromagnetic noise

When electrical temperature monitoring is unsafe

fiber optic does not present a spark hazard can be a significant safety advantage.

Advantage of DTS

DTS systems represent a cost-effective method for obtaining thousands of accurate, high-resolution temperature measurements.

DTS technology offers a safe and non-intrusive measurement with has the capability to pinpoint the precise location of any warm or cold spot instantly.

Thank you for your attention