7.New Approaches in Hazardous Areas - Fieldbus Foundation · sSaudi Aramco Khursaniyah, Hawiyah and...
Transcript of 7.New Approaches in Hazardous Areas - Fieldbus Foundation · sSaudi Aramco Khursaniyah, Hawiyah and...
Cooper Industries: Confidential
New approaches deliver safer, more reliable networks in hazardous areasRoger HightonMTL Instruments
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Foundation Fieldbus
w Major Oil and Gas companies use or standardize on Foundation Fieldbus technologys BPs Exxon Mobils Petronass Petrobrass Qatar Petroleums Reliances Saudi Aramcos Shells …
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Foundation Fieldbus
w World’s largest Petrochemical plants use Foundation Fieldbuss Shell Nanhai (China)s BP Secco (China)s Reliance JERP (Jamnagar Export Refinery Project)
(India)s Qatar Gas II (ME)s Qatar Petroleum/Shell Gas to Liquid plant (ME)s Saudi Aramco Khursaniyah, Hawiyah and Rabigh (ME)
Options for non-fieldbus systems
Ex i Intrinsic Safetys Very safe, allows ‘hot’ workings Need IS interfaces, design expertises Ex ic/Ex nL non-incendive for Zone 2
applicationsEx d Flameproof/Ex e Increased Safetys Widely used, good experience, simples Only ‘cold’ working permitss Ex nA non arcing for Zone 2 applications
Options for fieldbus systems
Intrinsic Safetys Retains live-working benefits common to all IS circuitss FISCO addresses device limitations of ‘Entity’ solutions Some limitations on cable length and number of devices in IICs Live work trunk and spurss FNICO/FISCO ic provides more power in Zone 2 applications
Flameproofs No Ex limitation on number of devices per segments How to disconnect one device without de-powering segment?s Not preferred for fieldbus – there are better options
Combination techniquess Fieldbus Barrier (high energy trunk; IS spurs)s Ex nA non arcing trunk Ex ic/Ex nL non incendive for Zone 2s No live work on trunks Live work on spurs/devicess Option of live connection/disconnection of fieldbus barrier module
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Topologies
Safe Area Zone 2 Zone 1 & Zone 0Zone 1
Ex dEx nL/icEx nA FISCOor Ex i*
FISCOor Ex i
Instrument located in …
InstrumentProtection
method
Non-Ex
NI HET for Z. 2FNICO/
FISCO icNon-Ex
FISCO orEx nL/ic
Ex d FISCO HET
#
*: With Spur Connector. #: Grey Megablock either in Zone 2 or with Ex d box in Zone 1. Yellow Megablock in Ex e box in Zone 1.= no live maintenance. = Live maintenance allowed. %: For live maintenance, ensure Ui ≥ U0.
Entity
%
Topology to use… Note: NI = Non-incendive (Ex nA); HET = High Energy Trunk)
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Applications - High Energy Trunk
l Solution for any Zone, any Gas Groupl Compatible with Entity and FISCO field devicesl Capable of long cable runsl Trunk power can be redundantl Multiple-unit enclosure options availablew Popular in large oil refining and petrochemical complexess e.g. Reliance Jamnagar Export Refinery Project
• >13,000 FF instruments• >3,600 segments
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Applications - FISCO
w IEC 60079-27 FISCO standardw Suits users who like fully Ex i systemsw Eliminates the need to calculate cable parameters (!)w Reduces safety documentation to a list of devicesw Allows addition of devices without a review of safety
documentationw Cable runs limited s typically fieldbus trunk 2/3 distance of Fieldbus Barrier
w Popular in medium size petrochemical plants, chemical plants, upstream oil and offshore. s e.g. Shell Bonny Island terminal
• >5,000 FF instruments
‘Physical layer’ expectationsw Users request:s Higher Reliability
• Redundancy• Simplification
s Safety• Removal of risks from inadvertent/unskilled maintenance• Use of intrinsic safe where possible in hazardous areas
s Ease of use• Flexible hardware solution
s Maintainability• ‘Pluggable’ modules• User-friendly, ergonomic construction
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‘High Energy Trunk’ concept
FISCO or Entity fieldbus devices
FIELD
CONTROL ROOM
Zone 1Division 2
GAS DUST
Zone 1/0Division 1
Zone 21
Zone 21/20
Control system
Redundant FF power supply
Live-workable Ex i spurs
Fieldbus barriers
High energy Ex e trunk
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High Energy Trunk Practical Solution
Live Ex de disconnect switches: allow replacement of a faulty fieldbus barrier
Separate terminator: segment still terminated even if any of the fieldbus barriers removedSurge protection: often required since built-in SP’s are only basic (for very small surges)Wiring, ducting: clean wiring required to avoid wrong maintenance
Ex e wiring block under plastic cover: allows opening compartment to access switches
Wiring blocks: Required for incoming field wiring as terminals on FBB are not replaceable
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High Energy Trunk Practical Solution
Number of terminals:Spur: + / - / Shield of FBB to + / - / Shield of Surge Protector. There are 12 spurs = 72Spur: + / - / Shield of Surge Protector to + / - / Shield of screw terminal. There are 12 spurs = 72Trunk: + / - / Shield of FBB to + / - of Ex de switch. There are 3 Trunks = 15Trunk: + / - of Ex de switch to + / - / Shield of Ex e terminals. There are 3 Trunks = 15Total = 72 + 72 + 15 + 15 = 174 terminals = 174 Potential points of failure
New-Generation ‘High Energy Trunk’ architecture
“Live pluggable”
Fieldbus Barrier modules
Spur surge protector (optional)
Pluggable Terminator
Trunk terminals
Pluggable trunk surge protector
(optional)
Trunk Terminal Assembly
(TTA) housing
Screw-secured,
pluggable spur
terminals
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Pluggable modules aid maintainability
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Fieldbus Terminator and Trunk Surge protector modules plug into dedicated sockets in the ‘Trunk Terminal Assembly’
• May be removed and replaced while under power without ‘gas clearance’
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Retro-fittable components add flexibility
w Many details are still unconfirmed during FEED:w Which fieldbus spurs require surge protection?w How many spurs are required per field junction box?
w Ability to retro-fit surge protection and barrier modules adds flexibility during the design and construction process
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Smaller field enclosures lead to significant savings in infrastructure and installation costs
Replace this...
“Honey, I shrunk the Fieldbus Barrier”
950mm
430mm
.....with this
Every module and circuit within the shaded area is live-
workable in the hazardous area
Mixing circuits that can be live-disconnected in a hazardous area with those that can’t leads to unnecessary risks during field maintenance – which is
why all circuits and modules in the main enclosure compartment are designed to be interruptible while powered.
Reducing maintenance risk
Non-live workable circuits are confined within the Trunk Terminal compartment and protected by a cover
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Summary
w Compact, modular constructionw No interconnecting wiring inside main enclosure
compartments Eliminates complexitys Higher reliability
w Integrated, pluggable surge protections Flexible to users’ needss Suitable to retrofit
w All modules hot/live-pluggables No additional isolating switches requireds Reduces risk of explosion due to wrong operation
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FISCO
FISCO power supply
FIELD
CONTROL ROOM
Live-workable Ex i spurs
FISCO fieldbus devices
24Vdc24Vdc
Live-workable Ex i trunk
GAS DUST
Control system
Zone 1 / Div1Hazardous Area
Zone 21Hazardous Area
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FISCO
Features of FISCO:w Trunk and Spurs are intrinsically safew High reliability (typically higher than high energy trunk concept)w Typically 12 instruments (typically limited by cycle time)w Most economic concept for any number of instrumentsw Verification of intrinsic safety documented by FISCOw No mix of protection methods – Safest technology of all
Considerations:w FISCO supply is singlew Cable distance shorter than with High Energy Trunks Use thicker cable to compensate voltage drop
w Mainly used for FISCO instruments, not Entitys Study1 showed that 93% of instruments are FISCO certifieds Use spur connector to connect to Entity instruments/Zone 0
1 http://forums.fieldbus.org/showthread.php?t=2205
FISCO Power Supply Redundancy
w Increasingly specified for critical process applications requiring high system availability
w Recommended in Fieldbus Foundation Engineering Guide, AG181s “Fieldbus Power Supplies/Conditioners should be
redundant…” (Clause 5.2.2)w Power supply redundancy significantly increases availability
of the fieldbus segment, and hence of the overall control system
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Redundant FISCO power supply
FIELDZone 1
CONTROL ROOM
24Vdc24Vdc
Fieldbus control system (DCS)
Bulk power input
Intrinsically safe FISCO Fieldbus devices
Intrinsically Safe Field wiring hub
Intrinsically Safe trunk and spurs(1 segment of 4)
Redundant FISCO
Redundant FISCO power supplies
Ø On power-up, output is defaulted to FISCO A
Ø On detected failure of FISCO A or corresponding Supply Arbitration Module, FISCO B is selected
Ø Failure notification is given (open-circuit alarm)
Ø LEDs indicators identify failed module, to allow replacement under power
FISCOPower Supply
A
FISCOPower Supply
A
SAM
A
SAM
A
FISCOPower Supply
B
FISCOPower Supply
B
SAM
B
SAM
B
IS H1 to Field
Failure alarm
HAND-SHAKINGHAND-SHAKING
SAM = Supply Arbitration
Module
Host Control System
H1
IS Megablock
IS field instruments
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Redundant FISCO
w Change-over is bumplessw FF-831 specifies behaviour of fieldbus network when
power supply drops to 0Vw Fieldbus devices are required to survive the complete
collapse of the bus for 500usw If the change-over coincides with a data packet, data will
simply be retransmitted (mechanism of Foundation fieldbus protocol)
w Fieldbus communication “as usual”w No loss of controlw No loss of data
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Conclusion
w With Advanced High Energy Trunk and Redundant FISCO, alternative concept continue to co-exist
w High Energy trunk becomes safer and more reliablew FISCO remains the safest topology, and strengthens its
position as the most reliable.
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Thank you! Questions?
Roger HightonMTL InstrumentsGreat MarlingsButterfieldLuton, LU2 8DLUK+44 1582 [email protected]://www.mtl-inst.com