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Santos Siemens SGT400 Fleet:Commissioning, Start-up and Initial Operations
Richard Nolan, Team Leader Reliability Engineering23rd November 2016
Fleet Overview
Availability Case Study
Commissioning
RCA Investigations
─ GG Inlet Vibration
─ GTC Aux GB Shaft Failure RCA
Conclusions
Fleet Overview
16 SGT400 Packages across three upstream compression facilities
─ 7 Mechanical Drives (2 stage and 3 stage centrif GTCs)
─ 9 Generator Sets
─ Houston packaged, global supply chain
SGT400 Common Driver
─ 13MW, twin-shaft design
─ 2 stage CT and PT
─ Lincoln, UK supply
GTC Package
─ STC-SV 2 stage and 3 stage centrifugal compressors
─ Main export compressors for gas transmission to Curtis Island LNG plant
GTA Package
─ Converteam/GE Alternator
─ 11kV 50 Hz
─ Provide power to compression facilities, camps and well overhead feeders
Installed 2013
Commissioning 2014/15
First Annual services 2015/16
Availability Case Study
Fairview GTC fleet priority for production and availability
Final package handover May 2015
‘Bad Actor’ Rectification
─ Thermocouple Node Vibration
─ BOVs
─ Combustion Dynamics
─ Process Equipment
─ Seal Gas Panels
Transition from Reactive to Proactive
RCA Investigations and Rectification
Remote Condition Monitoring Capability Commissioning Close Out
RCA Investigations, Bad Actor Rectification
RCA Rectification, Steady Ops
Commissioning
12 month total duration (16 packages handed over to ops)
Operations staff embedded during commissioning phase
Overseas OEM GT commissioning team
Key Issues
─ PLC code mods and config control
─ LO Flushing
─ LO Pressure Stability
─ GTA load sharing
─ Seal gas panel PCV control
─ Centrif compressor casing drains
─ GTA Alignment
Operator/OEM Relationship
RCA Investigations
GG Inlet Vibration
─ Characterised by initial start to start variability
─ Joint investigation and collaboration between Santos and Siemens
─ Rectification covered under warranty
─ Fleet mitigated with upgraded GG inlet no 1 bearing
Aux GB Output Shaft Failure
─ Loss of drive to main LO pump
─ Damage to GG, PT and LP centrifugal compressor
─ Joint RCA between Santos and Siemens (ongoing)
─ RCA focus on Aux GB: Main LO pump coupling
─ Follow up LO system investigation
GG Inlet Vibration RCA: 3 Month Trend
Start to Start Variance
Bearing Degradation
GG Inlet Vibration RCA Spectrums: 24 hr cycles
GG Inlet Vibration RCA
Engine removed from service and returned to UK
Significant 9 month investigation
Synchronous Vibration and variance due to more than one GG rotor characteristic
─ Disc 9/Exis Stub Shaft eccentric growth
─ Blade scatter
─ Demonstrated via modelling and HSB testing
Sub Synchronous vibration attributed to fretting of inlet bearing radial pads
Key Activities
─ HSB testing of failed bearing
─ 3rd party analysis (OEM supplier and Tribology)
─ Fleet retrofit of upgraded bearing
Upstream Teeth
Downstream Teeth
Compressor Disc 9 and Exit Stub Shaft HirthTeeth Interface
- Thermal effects cause relative radial movement (150 – 200 um) at Disc 9/ESS HT interface, demonstrated by wear markings
- Asymmetric or eccentric growth at Disc 9/ESS has highest impact on rotor balance as shown by rotor modelling sensitivity analysis
GG Inlet Vibration RCA
HSB testing focused on start to start repeatability of SGT400 rotor
─ No thermal effects
─ Testing with CT attached and removed
─ Full stop and slow speed spin testing
Poor repeatability demonstrated when full stops carried out between runs, variation of 20um visible.
Improved repeatability when rotor reduced to 900rpm between runs
Poor repeatability is not significant enough to be the only root cause
14300rpm – full stop 14300rpm – 900rpm spin
GG Inlet Vibration RCA
GTC Aux GB Shaft Failure RCA
GTC Aux GB Shaft Failure RCA
GTC Aux GB Shaft Failure RCA
- 6 weeks downtime. GG, PT, Aux GB, Main LO Pump, LP Bundle Replaced.
- Root cause focused on installation and material vulnerability of Aux GB to Main LO pump coupling
- Returned to service and shutdown following 24hr increase in dP across LO Filters
- Main LO pump damage cause of high filter dP
- OEM pump supplier inspection on site
- GTC Fleet Inspection and pump retrofit
- Significant collaborative effort between operator and OEM required
Conclusions
Commissioning
─ Resource Consistency (Operator and OEM)
─ Configuration management across sites
─ Prioritising full close out of technical issues
─ First real opportunity to develop operator/OEM relationship
Operational Support
─ Operator and Maintenance teams package familiarity
─ Remote condition monitoring capability
─ OEM Embedded Engineer
─ Training (right people, right time)
RCA Activities
─ Huge international collaborative effort (and challenge)
─ Separate technical/commercial as far as possible
─ Significant time and expense spent by OEM
Operator/OEM Relationship
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