DGA - Method in the Past and for the Future Ivanka Atanasova-Höhlein © Siemens AG Page 2 May 2012 Ivanka Atanasova-Höhlein © Siemens AG Energy Sector 1970 Doerenburg introduced the differentiation between electrical and thermal failure mode and introduced ratios for fault gases with similar solubility. 1973 Halstead developed the theoretical thermodynamic theory. The ratios are temperature dependent. With increasing the hotspot the amount of gases increases in the order: methane-ethane-ethylene. 1975 The evaluation scheme of the modern Gas-in-Oil Analysis is developed by Rogers, Mueller, Schliesing, Soldner (MSS). 1995 Development of In-Line Monitoring Page 3 May 2012 Ivanka Atanasova-Höhlein © Siemens AG Energy Sector Different phenomena in oil take place like: dielectric thermal Change/Ageing dynamic chemical ! Gas-in-Oil Analysis (DGA = Dissolved Gas Analysis) Page 4 May 2012 Ivanka Atanasova-Höhlein © Siemens AG Energy Sector The measurement of dissolved gases allow the knowledge on ! Type ! Complexity ! Seriousness of event Page 5 May 2012 Ivanka Atanasova-Höhlein © Siemens AG Energy Sector Sampling Page 6 May 2012 Ivanka Atanasova-Höhlein © Siemens AG Energy Sector Sampling Container ! Perfectly cleaned & Dried ! Free from dust & moisture ! Airtight ! Glass or Metal cans, syringes Page 7 May 2012 Ivanka Atanasova-Höhlein © Siemens AG Energy Sector ! Protect sample from direct light ! Avoid moisture & dust contamination ! Use the sampling containers exclusively for transformer oil sampling Page 8 May 2012 Ivanka Atanasova-Höhlein © Siemens AG Energy Sector 1 Handwheel 2 Sealing cap 3 Safety chain 4 Polyamid gasket 5 Nut 6 Drain valve 7 Hose and screw connector 8 Sampling bottle 9 Overflow vessel Page 9 May 2012 Ivanka Atanasova-Höhlein © Siemens AG Energy Sector Page 10 May 2012 Ivanka Atanasova-Höhlein © Siemens AG Energy Sector Required information concerning oil sample(example) Requested analysis: Colour ISO 2049 Appearance IEC 60422 Neutralisationvalue IEC 62021-1 Breakdownvoltage IEC 60156 Water content IEC 60814 Loss factor at50Hz IEC 60247 Interfacial tension ISO 6295 PCB-content EN 12766-2 Furananalysis (DGA) IEC 61198 Gas-in-oil-analysis IEC 60567 Please fill in the following data: Manufacturer: FTNR (ManufacturingNo.): Customer: WNR (Order No.): Location: SampleNo.: Year ofmanufacture: Datesampletaken.: Type: Typeofoil Power: Quantity ofoil: Rating: Oiltemperaturein thesampletaken: Sampletaken from: Oil samplevalve Oil drainagedevice A 22/31/40DIN 42551 Others Tank: Top Middle Bottom conservator Transformer OLTC Bushing OLTC OLTC tank Bushing Others: Reason for sampletaking: Dateofoperationfault: Dateofrepair : Dateofoil treatment/reclaiming Routinecheckup: Further informations andprevious history: Sampletaker: Date Lab information: Page 11 Consecutiveno.: Datesamplereceived: Datesampleanalysed: Typeofsamplecontainer: May 2012 Nameinblock letters Company/Department Phone specialfeatures: Ivanka Atanasova-Höhlein © Siemens AG Energy Sector Extraction of Gases from the Oil Page 12 May 2012 Ivanka Atanasova-Höhlein © Siemens AG Energy Sector DGA. Toepler Pump Page 13 May 2012 Ivanka Atanasova-Höhlein © Siemens AG Energy Sector DGA. Partial Degassing Page 14 May 2012 Ivanka Atanasova-Höhlein © Siemens AG Energy Sector DGA. Headspace at Ambient Temperature Page 15 May 2012 Ivanka Atanasova-Höhlein © Siemens AG Energy Sector DGA. Headspace at 70°C Page 16 May 2012 Ivanka Atanasova-Höhlein © Siemens AG Energy Sector Gaschromatographic Analysis Page 17 May 2012 Ivanka Atanasova-Höhlein © Siemens AG Energy Sector Gaschromatographic Analysis Sample injection Carrier Gas Page 18 May 2012 Detector Detector gas Ivanka Atanasova-Höhlein © Siemens AG Energy Sector Failures which can be identified by DGA ! Partial discharges ! Electrical discharges ! Charcoal coating of contacts ! Accelerated cellulosic degradation ! Local overheating ! Untightness of OLTC tank ! Catalytic reactions of materials ! Additional information from BHR gas Page 19 May 2012 Ivanka Atanasova-Höhlein © Siemens AG Energy Sector Failures which can not be identified by DGA ! Incipient Failures ! Long lasting temperatures < 150 °C Page 20 May 2012 Ivanka Atanasova-Höhlein © Siemens AG Energy Sector Interpretation Schemes Page 21 May 2012 Ivanka Atanasova-Höhlein © Siemens AG Energy Sector Duvals Triangle Page 22 May 2012 Ivanka Atanasova-Höhlein © Siemens AG Energy Sector Patterns Electrical Discharges Page 23 May 2012 Thermal Problem Ivanka Atanasova-Höhlein Partial Discharges © Siemens AG Energy Sector MSS Scheme Ratio ranges <0.3 0.3 to < 1.0 1.0 to < 3.0 3.0 to < 10.0 ! 10.0 Diagnosis Normal ageing of insultans Discharge of high energy Discharge of low energy Partial discharge with high energy Partial discharge with low energy Local overheating up to 300 ºC Local overheating from 300 ºC to 1000 ºC Local overheating over 1000 ºC Local overheating and discharge Local overheating and partial discharge [C2H2] [C2H6] 0 1 1 2 2 0 2 2 1 1 0 0 1 1 0 n.i. = not indicative Page 24 May 2012 Ivanka Atanasova-Höhlein Ratio numbers [H2] [C2H4] [C2H4] [CH4] [C2H6] [C3H6] 0 0 0 0 0 1 1 1 2 2 1 3 3 1 3 Number sequences 0 0 0 1 1 2/3 2 1 2/3 3 0 n.i. 3 0 n.i. 0 0 1 0 1 2 0 1 2/3 1 1 2 3 1 2 [CO2] [CO] 1 1 1 0 2 0 1 1 0 0 2 2 2 2 2 © Siemens AG Energy Sector IEC Scheme Page 25 May 2012 Ivanka Atanasova-Höhlein © Siemens AG Energy Sector In case of quotient information it must be clear, that quotients are only representative, if following values of the fault gases (in ppm) are exceeded: Page 26 May 2012 C2 H 2 !1 H2 ! 15 " [CXHY] x=1;2;3 ! 50 CO ! 80 CO2 ! 200 Ivanka Atanasova-Höhlein © Siemens AG Energy Sector DGA Example – thermal Problem MSS-Code 00120 Fault gas ppm Hydrogen H2 1967 Methane CH4 8008 Ethane C2H6 2013 Ethylene C2H4 8323 Acetylene C2H2 57 Propane C3H8 401 Propylene C3H6 4824 Carbon monoxide CO 253 Carbon dioxide CO2 1903 Oxygen O2 18222 Nitrogen N2 61662 Page 27 May 2012 Ivanka Atanasova-Höhlein © Siemens AG Energy Sector MSS-Code 00120 Fault gas ppm Hydrogen H2 Methane CH4 1041 Ethane C2H6 295 Ethylene C2H4 1726 Acetylene C2H2 25 Propane C3H8 83 Propylene C3H6 1012 Carbon monoxide CO 1047 Carbon dioxide CO2 6158 Oxygen O2 11805 Nitrogen N2 58084 Page 28 May 2012 Manufacturing year 1970 360 MVA Carbon deposits on PLTC Contacts 537 Ivanka Atanasova-Höhlein © Siemens AG Energy Sector Gas-in-Oil Analysis Turn-to-Turn Fa MSS-Code 21121 Fault gas ppm Hydrogen H2 4973 Methane CH4 1758 Ethane C2H6 243 Ethylene C2H4 2813 Acetylene C2H2 8236 Propane C3H8 58 Propylene C3H6 1320 Carbon monoxide CO 1196 Carbon dioxide CO2 2431 Oxygen O2 6743 Nitrogen N2 44120 Page 29 May 2012 Ivanka Atanasova-Höhlein © Siemens AG Energy Sector DGA Thermal Problem with Partial Discharges MSS-Code 00101 Fault gas ppm Hydrogen H2 1060 Methane CH4 2481 Ethane C2H6 703 Ethylene C2H4 2187 Acetylene C2H2 4 Carbon monoxide Carbon dioxide CO CO2 Page 30 May 2012 Manufacturing year 1991 234 MVA, 330 kV Defective welding joint 450 995 Ivanka Atanasova-Höhlein © Siemens AG Energy Sector DGA Catalytical Effects MSS-Code ?3??0 Fault gas ppm Hydrogen H2 Methane CH4 Ethane C2H6 <1 Ethylene C2H4 <1 Acetylene C2H2 <1 Propane C3H8 <1 Propylene C3H6 <1 Carbon monoxide CO 67 Carbon dioxide CO2 222 Oxygen O2 5180 Nitrogen N2 23700 Page 31 May 2012 Manufacturing year 1977 Closed type Color 0,5 / Acidity 0,01 488 1 Ivanka Atanasova-Höhlein © Siemens AG Energy Sector DGA Untight OLTC MSS-Code 22122 Fault gas ppm Hydrogen H2 Methane CH4 25 Ethane C2H6 5 Ethylene C2H4 81 Acetylene C2H2 288 Propane C3H8 5 Propylene C3H6 50 Carbon monoxide CO 143 Carbon dioxide CO2 1920 Oxygen O2 24600 Nitrogen N2 52000 Page 32 May 2012 128 Ivanka Atanasova-Höhlein © Siemens AG Energy Sector DGA Diagnostic Importance in Service Page 33 May 2012 Ratios Gas increase rates Absolute Values Trend Ivanka Atanasova-Höhlein © Siemens AG Energy Sector Absolute Values IEC 60599 (VDE 0370-7) C2H2 All transformers No OLTC 2 " 20 Communicating OLTC 60 " 280 Page 34 May 2012 H2 CH4 C2H4 C2H6 CO CO2 50 " 150 30 " 130 60 " 280 20 " 90 400 " 600 2800 " 14000 Ivanka Atanasova-Höhlein © Siemens AG Energy Sector Ratios a) Eliminates the effect of the oil volume b) Eliminates some effects of sampling c) Especially interesting is the ratio formation for fault gases which exhibit similar solubilities, but their development is temperature dependent – e. g. the thermodynamic considerations of Halstead. Page 35 May 2012 Ivanka Atanasova-Höhlein © Siemens AG Energy Sector Thermodynamcal considerations of Halstead Page 36 May 2012 Ivanka Atanasova-Höhlein © Siemens AG Energy Sector Gas Increase Rates – information on seriousness of failure C2H2 All 0,01 transformers H2 CH4 C2H4 C2H6 CO CO2 0,36 0,33 0,40 2,9 27 0,25 ! 90% gas increase source: Cigre TF11 in ppm/day Gas increase rates are temperature and volume dependent Page 37 May 2012 Ivanka Atanasova-Höhlein © Siemens AG Energy Sector Trend Analysis Development of the Fault Gases After Two Months of On-Line Monitoring 100 600 500 80 70 400 ppm CO 2 60 50 300 40 200 30 20 100 ppm H 2, CO,CH 4, C2 H4, C2 H6, top oil (°C) 90 Carbon Dioxide Hydrogen Methane Carbon Monoxide Ethane Ethylene top oil temp °C 10 0 1.7.08 0 11.7.08 21.7.08 31.7.08 10.8.08 20.8.08 30.8.08 9.9.08 Sa m pling da te Page 38 May 2012 Ivanka Atanasova-Höhlein © Siemens AG Energy Sector Trend Analysis 40 6 35 5 4 top oil (°C) 25 20 3 15 2 40 6 Ratio C 2H 4/C 2H 6, CH 4 /H2 30 10 1 35 5 5 30 0 top oil (°C) 20 3 15 2 1.7.08 Ratio C 2H 4/C 2H 6, CH 4 /H2 4 25 0 11.7.08 Top oil Temperature (°C) 21.7.08 31.7.08 10.8.08 20.8.08 30.8.08 9.9.08 Sa m pling da te C2H4/C2H6 CH4/H2 10 ! Trendanalysis is important not only with absolute values, but also with the ratios. 1 5 0 1.7.08 0 11.7.08 21.7.08 31.7.08 10.8.08 20.8.08 30.8.08 9.9.08 Sa m pling da te Page 39 May 2012 Ivanka Atanasova-Höhlein © Siemens AG Energy Sector Top C2H CH On-Line Monitoring # Early failure recognition # Diagnosis is only possible with the sofisticated types – where IEC ratios can be built Cigre TF 15 DGA did a comparison between On-Line monitoring systems and Off-Line analyses. The brochure is on the way. Evaluated are: " Precision " Longterm stability " Repeatability In case of " Routine concentrations, d.h. 5 * Detection Limit " Low Concentrations, d. h. 2-5*Detection Limit Page 40 May 2012 Ivanka Atanasova-Höhlein © Siemens AG Energy Sector Recommendation of Cigre A2.27 for On-LineMonitoring # Necessary in case a problem has been identified # Often, however, difficult to maintain # Interfaces can lead to problems # Able to deliver important information in a short time # Does not automatically lead to higher reliability Page 41 May 2012 Ivanka Atanasova-Höhlein © Siemens AG Energy Sector What can be measured on-line: ! Temperature ! Current, Voltage ! OLTC ! Oil level ! Gas-in-Öl Analysis ! Humidity in oil ! Bushings ! Acoustic Signals ! Magnetic Circuit ! Coolers Page 42 May 2012 Ivanka Atanasova-Höhlein © Siemens AG Energy Sector More Data does not mean automatically more Information Data Explosion1) (Total Exabytes) 200 150 100 50 0 2002 2003 2004 2005 1) Exa = 1016 = 10 Mil of Billions Page 43 May 2012 Ivanka Atanasova-Höhlein 2006 2007 © Siemens AG Energy Sector Transformer Failure Rate $ Failure rate Failure at Comissioning Failure because of aging Constant failure rate Page 44 May 2012 Ivanka Atanasova-Höhlein Aging / years % © Siemens AG Energy Sector Future Developments # Further development of the On-Line analysis with decision criteria # Gas-in-oil analysis in OLTC # Gas-in-oil analysis in alternative insulation fluids and high temperature insulating materials Page 45 May 2012 Ivanka Atanasova-Höhlein © Siemens AG Energy Sector Thank you for your attention! © Siemens AG