Using SF6 Analysis for Condition Based Maintenance of ...
Transcript of Using SF6 Analysis for Condition Based Maintenance of ...
Using SFUsing SF66 Analysis forAnalysis forCondition Based Maintenance ofCondition Based Maintenance of
Circuit Breakers andCircuit Breakers andGas Insulated SubstationGas Insulated Substation
Antony GiacominTJ|H2b Analytical Services, Pty. Ltd.
Reasons for TestingReasons for Testing
�� Acceptance testing (purity)Acceptance testing (purity)�� SafetySafety�� Handling & processingHandling & processing�� Fault identification/failure mode processesFault identification/failure mode processes�� Wear outWear out
AACCEPTANCE TESTINGCCEPTANCE TESTING
�� Numerous new suppliers have entered Numerous new suppliers have entered marketmarket
�� SF6 is manufactured for different SF6 is manufactured for different applicationsapplications
SAFETYSAFETY
�� Numerous decomposition products formed Numerous decomposition products formed –– many toxicmany toxic
Threshold Limit Values in Threshold Limit Values in ppmppm of SFof SF66Gaseous Decomposition ProductsGaseous Decomposition Products
SF6 Sulfur hexafluoride 1000SO2 Sulfur dioxide 3SF4 Sulfur tetrafluoride 0.1SOF2 Thionyl fluoride 1SO2F2 Sulfuryl fluoride 5SOF4 Thionyl tetrafluoride 0.5WF6 Tungsten hexafluoride 0.1CF4 Carbon tetrafluoride 1000
Threshold Limit Values in Threshold Limit Values in ppmppm of SFof SF66Solid Decomposition ProductsSolid Decomposition Products
AlF3 Aluminum fluoride 2.5CuF2 Cupric fluoride 1CuF Cuprous fluoride 1
Handling & ProcessingHandling & Processing
�� Uncontaminated SFUncontaminated SF66
�� SFSF66 slightly contaminated with SFslightly contaminated with SF66breakdown productsbreakdown products
�� SFSF66 severely contaminated with SFseverely contaminated with SF66breakdown productsbreakdown products
�� SFSF66 contaminated with moisturecontaminated with moisture�� SFSF66 slightly contaminated with airslightly contaminated with air�� SFSF66 severely contaminated with airseverely contaminated with air
UncontaminatedSF6
Slightlycontaminated
SF6 with breakdownproducts
Severelycontaminated
SF6 with breakdownproducts
Slightlycontaminated
With air
Severelycontaminated
With air
ContaminatedWith moisture
AssessSF6
condition
Collect SF6Sample
Store and reuse
As needed
Filter and retest until
acceptable, then reuse
Reprocess SF6
Filter and retest until
acceptable, then reuse
Add new SF6 untilresidual air acceptable.
Reuse as needed
Reprocess SF6
CIGRE 23.10 CIGRE 23.10 -- “SF6 Guidelines” “SF6 Guidelines” ELECTRA No. 173 (1997)ELECTRA No. 173 (1997)
�� InIn--service service guidelinesguidelines..
�� Total Air (O2 & N2): Total Air (O2 & N2): 30,000 ppm30,000 ppm
�� Water content: 200 Water content: 200 ppmv.
�� Recycling or reRecycling or re--use use guidelines.guidelines.
�� Total Air (O2 & N2): Total Air (O2 & N2): 20,000 ppm20,000 ppm
�� Water content: 120 Water content: 120 ppmvppmv.ppmv. .
DIAGNOSTIC TESTINGDIAGNOSTIC TESTING
�� Measuring various levels of Measuring various levels of decomposition products enables decomposition products enables detection of failure modes, faults and detection of failure modes, faults and wear activity.wear activity.
ELECTRIC DISCHARGESELECTRIC DISCHARGES
Type Occurrence Characteristics
Partial Discharge Electrically floating component Free conducting particles 0.01 – 0.010 J
102 – 104 Hz
Spark Capacitive discharge Disconnect switch 0.010 – 100 J
a few �s duration
Arc Breaker switch In-service fault 105 – 107 J
50 – 150 ms
Contamination with AirContamination with Air
�� Residual OResidual O22, N, N22, H, H22O from fillingO from filling�� Absorbed & Adsorbed OAbsorbed & Adsorbed O22, N, N22, H, H22OO�� Ingress of OIngress of O22, N, N22, H, H22O through leaksO through leaks
SF6
SF5
SF4
SF3
SF2
SF
S
OH SOF4
SOF3
SOF2
SOF
SO
OH SO2F2
O
SOF4
SOF2
SO2F2
SO2F2
SO2F2SOF2
SO2F
SO2
SO2
OH
OH
OH
OH
H 2O
H 2O
H 2O
O2
O2O
O
O
O
O
F
F
F
F
F
e
Fe
O
e
O
e
e
F
e
CF4
Cu
(copper) CuF2 (solid)
W
(tu
ngste
n)
WF6
C
(c
arbo
n)H2O WO3 (solid)
SF6
Al(aluminum)
Al, O
2 , C
SOF2 + AlF3 (solid) + CF4
AlF3 (solid)
Key SFKey SF6 6 GasesGases
�� ActivityActivity�� SOFSOF22
�� SOFSOF44
�� SOSO22FF22
�� SOSO2
�� Wear OutWear Out�� CFCF44
�� WFWF66
2
Case 1 Case 1 -- Circuit BreakerCircuit Breaker
Compound Pole 1 Pole 2 Pole 3SF6 Sulfur hexafluoride 998191 995848 996190N2 Nitrogen 964 649 2917O2 Oxygen 341 136 638CF4 Carbon tetrafluoride 504 3365 255SOF2 Thionyl Fluoride ND 1 NDCO2 Carbon dioxide ND 1 ND
Case 2 Case 2 -- Gas Insulated Gas Insulated SubstationSubstation
Compound Segment 26 Segment 31SF6 Sulfur hexafluoride 825686 820579N2 Nitrogen 173657 178674CF4 Carbon tetrafluoride 184 329CO2 Carbon dioxide 255 254SOF4 Thionyl tetrafluoride 8 17H2 Hydrogen 210 146
Case 3 Case 3 –– 245kV Live Tank CB245kV Live Tank CB Compound SF6 Sulfur hexafluoride 670011N2 Nitrogen 144898O2 Oxygen 44409CF4 Carbon tetrafluoride 8719CO2 Carbon dioxide 18174SO2F2 Sulfuryl fluoride 3445SO2 Sulfur dioxide 109812COS Carbonyl Sulfide 533
Moisture 180 ppm
Sampling IssuesSampling Issues
�� AirAir�� MoistureMoisture�� Reactive surfacesReactive surfaces�� Sample pressureSample pressure