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Importance of oil selection & monitoring in power generation & transmission IPS Rome Feb 2017
Dr Peter Smith – Global Technology Manager
1 Date Month 2016 Footer Copyright of Shell International CONFIDENTIAL
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Agenda
• Technical challenges/trends for
turbine & transformers oils
• Selecting the correct oil
• Oil condition monitoring tests
• Conclusions
2 Feb 2017
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Industry Trends
3 Feb 2017
CHALLENGE
Between 2012 and 2016, the forecast average compound annual growth rate for India and China is 6.8 and 8% respectively
A growing and wealthier world population
Increasing demand for energy
Renewable energy and nuclear power are the fastest-growing energy sources, but fossil fuels will still supply 80% of world energy use
Changes in governmental policy
Environmental legislation changes in a drive to reduce emission levels
Incidents such as the recent energy shortage in France highlights the fragile nature of electricity generation capacity and the strain which is being placed on spare capacity as a whole.
Diminishing spare capacity in power grids around the world
Reliability of power generation
KEY DRIVER EXAMPLE
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Power Output
Reservoir Size
Operating Temperature
Deposit Formation
Oil & Asset
Life & Reliability
& Performance
Turbine trends = oil works harder
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Transformer trends = oil works harder
5 Feb 2017
Higher voltages to
improve transmission
efficiencies
Higher temperatures
Expectations for a longer operating life
Regulatory requirements
More frequent operation under overload and less redundancy in case of failure
Higher power / weight & volume ratios to reduce manufacturing and installation costs
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Oil performance
Turbine:
Prevent metal-to-metal contact
Cool
Corrosion/deposit prevention
Asset health information
6 Feb 2017
Transformer:
Electrically insulate
Cool
Corrosion/deposit prevention
Asset health information
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Selecting the right oil – global industrial specification examples
Plus OEM & utility specifications
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Specifications more demanding
8 Feb 2017
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Oil composition example
9 Feb 2017
Additives
Base Oil
Antioxidants
Corrosion inhibitor
Others
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Oil composition influence – hydrocarbon base oils
10 Feb 2017
GTL based oils, primarily iso-paraffinic, narrow molecular distribution, no impurities
Do not pack together like normal paraffins. Respond well to anti-oxidants giving maximum degradation resistance
Paraffinic molecules
Naphthenic molecules
variable performance, at low temperatures can form wax
variable performance, remain fluid at low temperature
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Oil degradation & impact on equipment life, reliability, & efficiency
11 Feb 2017
EFFECT CAUSE
Insoluble oxidation products
OIL OXIDATION Soluble organic acids, plus
Soluble polymeric material
• Insoluble oxidation products
• Soluble organic acids
Deposit formation (Sludge)
Oil thickening
Lacquering
Oil acidity increase
REDUCED OIL LIFE
Products of oil degradation are a cause of reduced oil/equipment life & performance
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Poor turbine oil selection
12 Feb 2017
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Poor transformer oil selection
13 Feb 2017
Source: IEC TC10 Cape Town 2005
0
50
100
150
200
250
Needle -sphere +ve
Needle -sphere -ve
Needle - plane+ve
Needle - plane-ve
conventional inhibited
Latest inhibited
10 mm gap
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Proactive oil condition monitoring
14 Feb 2017
• What to test for and why? • What limits do I use? • How frequently should I sample? • Where should I sample from? • What decisions should I make based on the results of the testing?
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Turbine oil condition monitoring example
15 Feb 2017
TEST FREQUENCY
STEAM TURBINE GAS TURBINE
Appearance (Visual)/Colour (ASTM D1500)
Quarterly/Bi-Annual Quarterly
Viscosity @ 40C Quarterly/Bi-Annual Quarterly
Total Acid Number (mg KOH/g) Quarterly/Bi-Annual Quarterly
Water Content (KF, ppm) Quarterly/Bi-Annual Quarterly
Elemental Analysis (ICP) Quarterly/Bi-Annual Quarterly
Particle Count (ISO 4406) Quarterly/Bi-Annual Quarterly
RPVOT (mins) Annual Quarterly
Voltammetry/FTIR (AO Trending) Annual Quarterly
Demulsibility (ASTM D1401,ml-ml-ml (mins) Annual Not Required
Rust Test (ASTM D665A) Annual Not Required
MPC (ASTM D7833) Not Required/Annual Quarterly
Foaming (ml-ml) (ASTM D892) Annual Annual
Air Release (ASTM D3427) Annual Annual
Flash Point (ASTM D892) Annual Annual
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Turbine oil oxidative stability by RPVOT ASTM D2272
16 Feb 2017
Turbine Oil in GE Frame 6B Gas Turbines
0
500
1000
1500
2000
2500
0 5000 10000 15000 20000 25000 30000 35000 40000 45000
Service Life (Hrs)
RP
VO
T (
min
s.)
③ RPVOT at 50% of initial value short time check sampling frequency & investigate cause
④ RPVOT at 25% of initial value & a high acidity at any time - consider oil change
① Measure RPVOT after fill
② Monitor frequently
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Turbine oil condition monitoring examples
17 Feb 2017
Jiangsu Shagong, China – steam turbine Excessive bearing wear
UK power station, combined cycle system Accelerated oil degradation
Asia, steam turbine Rapid bearing temperature increase
Scotford refinery, Canada – plant air compressor Bearing deposits/failure
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Transformer oil condition monitoring example EDF Heysham 2
18 Feb 2017
Transformer filled with Diala S4 ZX-I in 2013 after hot flush Hawker Siddley built 1980; 132 kV, 90 MVA
Source: EdF Energy
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Tap changer example – UK based DNO
19 Feb 2017
Oil optimisation = up to 3 x greater operational oil life
Reduction in number of oil changes/frequency - Increase in engineer efficiency
Reduction in oil installation time
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Conclusions Oils play a critical role in the availability & reliability of equipment used in power
generation, transmission & distribution, oil & gas, & heavy industry sectors
When selecting an oil considerations include: What does oil need to do in the application, reliability, life?
Performance specification?
Performance data available for the oil?
OEM and utility approvals, field performance data?
Oil condition monitoring considerations include: What to test & why?
Limits, frequency, sample point?
What decisions should be made based on the results of the testing?
20 Feb 2017
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Questions and Answers
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