DTSX3000 Distributed Temperature Sensor

Measurement Principle

Operating Principle

Yokogawa DTSX3000 measures temperature and distance over the length of an optical fiber using the Raman scatter principle. A pulse of light (laser pulse) launched into an optical fiber is scattered by fiber glass molecules as it propagates down the fiber and exchanges energy with lattice vibrations. As the light pulse scatters down the fiber optic cable, it produces stokes signal (longer wavelength) and anti-stokes (shorter wavelength) signal, of which both signals shifted from the launch of the light source. The intensity ratio of the two signals components depends on the temperature at the position where the Raman scatter is produced. This temperature can thus be determined by measuring the respective intensities of the stokes and anti-stokes signals. Furthermore, part of the scattered light, known as the backscatter, is guided back towards the light source. The position of the temperature reading can thus be determined by measuring the time taken for the backscatter to return to the source.

Raman Scattering

All light interacts with matter! For example, imagine standing in a pitch black garage with no external light source. Inside this garage is a bright red sports car. Needless to say, you cannot see the sports car or the color of the sports car itself. However, when you turn on the lights to the garage, you can immediately see the light source reflecting the bright red color off the car. The light that is bouncing off the red sports car is only bouncing off the "red" spectrum, therefore, your eyes see the sports car as, well, red.

Types of Scattering Light

Yokogawa's distributed temperature sensors measure temperature distribution using Raman scattering light, which exhibits particularly good temperature sensitivity among the following types of scattering light.

Measurement Method

Single-Ended Measurement Method

• This method launches optical pulses into only one end of the optical fiber for sensing. Easy to install, it is effective when the measuring target is long range.

Double-Ended Measurement Method

• This method launches optical pulses into both ends of a looped optical fiber for sensing.
• This method allows for continued measurement even if on place of the fiber optic cable is broken.

Comparison of Measurement Methods

Types of Temperature Sensors

Types of Temperature Sensors and Their Features

Comparison among Temperature Monitoring Methods

	Fiber Optic Sensor	Thermo Camera	Point Sensor (Thermocouple)
Description	Wide-area monitoring based on a fiber optic sensor	Surface temperature monitoring based on a thermo camera	Multipoint monitoring based on discrete sensors
Detection Method	Contact	Non-contact	Contact
Range of Temperatures Monitored	-200 to 300 °C (Based on a sensor cable)	Normal temperature to 2000 °C (Range switching required)	-200 to 1000 °C (Type K thermocouple)
Area	Coverage of a very wide area DTSX200: up to 6 km / ch DTSX3000: up to 50 km / ch DTSX1: up to 16 km / ch	Small viewing angle of 20°	Wide area
Advantages	Coverage of a very wide area and seamless monitoring	Capability of a limited tiny area monitoring	Capability of a limited tiny area monitoring
Disadvantages	Restricted to small areas	Non-seamless monitoring	Non-seamless monitoring Installation and maintenance of compensating lead wires

Performance

Representative parameters that indicate the performance of distributed temperature sensors include the spatial resolution and temperature resolution. In spite of the fact that in general, there is a trade-off relationship between these parameters, we have realized high performance based on signal processing technology.

Spatial Resolution

• The spatial resolution is the minimum length that detects changes in temperature (it is also referred to as the response distance).
• The spatial resolution is defined as the length when a temperature change of 10 to 90 percent of the optical fiber for sensing is detected.
• The sampling resolution represents the data interval, the definition of which is different from that of the spatial resolution.

Temperature Resolution

• The temperature resolution is defined by the standard deviation (1 σ) of measured values along the fiber optic sensor in a uniform temperature environment (in a thermostat chamber).
• The temperature resolution is the indicator of variations, which does not indicate temperature accuracy (the use of a reference thermometer in calibration makes it possible to make measurements with a higher temperature accuracy).
• Raman backscattering light is a very faint signal. By repeating measurements to average measured values, the distributed temperature sensors achieve a higher temperature resolution.

Examples of measurement results (DTSX200)

Types of cables

You can choose the most suitable type according to your intended use.

Normal Operating Temperature	Applications	Cable Type	Cable Details	Features
Normal Temperature	Conveyor Fire Detection Cable Temperature Monitoring Bus Duct Temperature Monitoring Cable Tunnel Fire Detection Warehouse Fire Detection Hot Spot Detection Cold Spot Detection etc.	Standard Type	Image Zoom	Nonmetal, lightweight, and easy to install EN 54-22 certified
		Robust Type	Image Zoom	Resistant to crush and tension and less likely to break EN 54-22 certified
		Flexible Type	Image Zoom	Thin and flexible and easy to install along the measurement targets
High / Low Temperature	Blast Furnace Monitoring Drying Furnace Monitoring LNG Leak Detection Well Monitoring etc.	Steel Tube Type	Image Zoom	Thin and flexible and easy to install along the measurement targets
		Steel Armored Type	Image Zoom	Resistant to crush and tension and less likely to break

Product Introduction

DTSX3000 Overview

The DTSX3000 distributed temperature sensor is configured by a DTS module, an optical switch module, a base module, a power supply module, and so on.

Variety of distance ranges selectable according to the target size.

• DTSX3000 -S : 10 km Range
• DTSX3000 -N : 16 km Range
• DTSX3000 -M : 30 km Range
• DTSX3000 -L : 50 km Range

On the Partner Portal Member Site, you can check the details of the specifications.
GS 39J06B40-01 : DTSXL Distributed Temperature Sensor Long Range System
GS 39J02B40-01 : DTSXL Distributed Temperature Sensor Long Range System (Software)

Optical Switch Module

Base Module

Power Supply Module

Accessory

DTRK10 Rack Mount Kit

Software

DTSX3000 Control Visualization Software (DTAP3000)

DTSX3000 data conversion software (DTAP3000D)

Specifications

Refer to the General Specifications for detailed specifications.

DTSX 3000

Optical Switch Module

Note:  As a guideline, the module should be replaced periodically every 4.7, 6, and 9.5 years for continuous operation of 15-second, 20-second and 30-second measurements, respectively.

REGULATORY COMPLIANCE and CONFORMITY to STANDARDS

Note: Under EU legislation, the manufacturer and the authorised representative in EEA (European Economic Area) are indicated below:
Manufacturer: YOKOGAWA Electric Corporation (2-9-32 Nakacho, Musashino-shi, Tokyo 180-8750, Japan).
Authorised representative in EEA: Yokogawa Europe B.V. (Euroweg 2, 3825 HD Amersfoort, The Netherlands).

Industries/Applicantions

Power

Yokogawa DTSX3000 can protect the infrastructure of existing power line/cable and reduce cost by monitoring the thermal dynamics of the power transmission and distribution line. By measuring the temperature of the power line, power grid operators can maximize the usable capacity of the power current by avoiding power cable damage and extending the cable life by maintaining optical power current. More importantly, operators can identify hot spots, fire breakout and location of fire along the entire grid. DTSX3000 minimizes the potential power grid network outages and streamlines preventative maintenance process. Because of its immunity to electromagnetic interference, DTSX3000 is ideal for high voltage, high noise environment. DTSX3000 is designed to deploy in the following environments:

• Underground power cables
• Subsea power cables
• Overhead power lines
• Distribution station
• Substations

Pipeline

Yokogawa DTSX3000 offers superior pipeline leak detection by using fiber optic solutions that provide a complete temperature profile along the entire length of a pipeline. When a leak occurs anywhere along the pipeline, a localized temperature change is produced at that specific location. The optical fiber cable, due to its close proximity to the pipeline, has adequate thermal contact and can provide accurate temperature readings. By comparing every new temperature profile scan acquired against a reference profile taken under normal conditions, it is possible to detect temperature anomalies which may indicate a possible pipeline failure or external extrusion which might result in or be an actual break. DTSX3000 is designed to deploy in the following applications:

• Gas pipelines: Ammonia, natural gas, carbon dioxide
• Liquid pipelines: Crude oil, heated oil, gasoline, PNG, LNG, brine, steam

A leak induced temperature change can be either from a localized cooling or heating. For leaks occurring in pipelines carrying crude oil and other similar products, it is expected that a localized warming will result from a leak as it is often a common practice to transport the crude at a warm temperature to reduce its viscosity.

Leaks in pressurized gas pipelines or those carrying LNG or other cryogenic products, a localized cooling effect will be observed as a result of the Joule Thompson effect, whereby a rapidly expanding gas under pressure lowers the surrounding temperature.

* Assuming appropriate scan rate and data refresh intervals are used

Fire Detection

Early fire detection to critical process and environment is an important component to any safety system. A blazing fire has devastating consequences to important assets, products and most importantly, human lives. Furthermore, the cost of downtime due to fire leads to lost opportunities and costly repairs. Discrete sensor technology often fails due to the surrounding environment conditions such as dust, humidity, heat and corrosion. In addition, it is expensive to maintain a conventional sensor technology due to constant repair. Yokogawa's DTSX3000 is designed to detect fire in critical assets under the most extreme conditions and offers unmatched reliability, performance and cost savings.

Yokogawa's DTSX3000 is designed to deploy in the following fire detection applications:

• Conveyor belts carrying important goods
• Tank farms
• Cable trays
• Underground tunnels
• Pipelines (underground, above ground)
• Nuclear facilities
• Mining, Refinery

* Assuming appropriate scan rate and data refresh intervals are used

Oil & Gas

The development of unconventional resources, such as heavy oil, oil sands and shale gas has been progressing in line with the increase in global energy demand. DTSX3000 can measure the temperature distribution along an optical fiber with a length of several kilometers are being applied to extraction of unconventional resources. DTSX3000 maximizes oil/gas extraction by providing real time continuous temperature measurement through different injection dynamics. In addition to well optimization, DTSX3000 provides critical data that help monitor and detect wellbore conditions for leaks, water penetration and gas breakthrough. DTSX3000 also provides control capability (measurement of flow, pressure, temperature, valve position, etc.) on top of fiber optic temperature measurement. More importantly, compared to conventional wellbore monitoring technology, DTSX3000 is more robust, cost effective and accurate.