Condition Assessment Of Transformer. By Aradhana Ray OMICRON

Transcription

1 Condition Assessment Of Transformer By Aradhana Ray OMICRON! " 1

2 ! $ % & ' ' ( ) $ * +, -. # 2

3 # $ % Obtain OEM design performance! " / Remark!"! #!! #! $%! & '!( )& * * +) 0 3

4 /, -!/2 3 # $#4 4-7 HV Bushing Measuring Tap LV Bushing Diverter Switch Tap Selector Core Tapped Winding High Voltage Winding Low Voltage Winding 5 4

5 , %, *,, 8 % * % % :

6 * ; < =,%,% <- =.,>,> - 3 ;? ' % ( 3. 1 < = 6

7 ',>.,& -. -! Microstructure of paper with Neutralization Number [mg/kg] (from left to right) # 7

8 ,,, / A. - < =!"#$ %! & $ %! $ H 2 O H 2 COOH OH H C O O C C CH H OH H CH H CH H 2 COOH OH CH C C C O H OH H 0 8

9 B Water accelerates the ageing of the Cellulose: 1000 Relative relative Depolymerisationsgeschwindigkeit speed of depolymerisation 80 C 100 C C [%] 4 water Wassergehalt content im in Papier paper To extend the lifetime, the water has to be removed from the insulation! 1 *? B ' C C "? B ' C& * C ' >( 5 9

10 > ' Measurements Dielectric measurements Physical measurements Chemical measurements Gas in oil-analysis Furane analysis Conclusions Condition of the oil Electrical condition of the transformer Condition of the Cellulose 8 %. A <> D= Dielectric measurements Standard Breakdown voltage VDE 0370 T5 = IEC Dielectric dissipation factor VDE 0380 T2 = IEC Physical properties Standard Refraction number DIN Density DIN Kinematic viscosity DIN Flash point DIN EN Pour Point DIN ISO 3016 Interfacial tension ISO 6296 Colour and Purity ISO 2049 / IEC Chemical properties Standard Water content in oil DIN IEC 814 = IEC Neutralization number DIN T2 IEC Saponification number DIN Sulphur content DIN Chloride content DIN Inhibitor content (IR Meth.) IEC

11 %. A <E? = % ) -? & % 511 ) -? & % 50 A? & % 8# A >? & % 81 >? & % 5/ A " $?? & % 085? & % /!! 7? & % /4 4? fi? & % 85 < =? & % /4 4 <fi =? & % /# A? & % #4 /8? & % 81# %? & %!0 11

12 C ( >* 04 # Power & Instrument Transformers 170 kv 420 kv Power Transformers 72.5 kv 170 kv Instrument Transformers < 170 kv Breakdown Voltage [kv] Dielectric Dissipation 90C Neutralization Number [mg KOH/g] Interfacial Tension [mn/m] Water Content [mg/kg]! C ( >* * *? 0388/ Power Transformers < 69 kv Power Transformers 69 kv 288 kv Power Transformers > 345 kv Breakdown Voltage [kv] ASTM 877 Dielectic 25C Neutralization Number [mg KOH/g] Interfacial Tension [mn/m] Water Content [mg/kg] F 0-7 F 0-7 F / 2 4 / 2 4 / 2 <4! 2 = G 4 G 4 G 4 F # F 0 F! # 12

13 % 6 / Dissolved Gas Analysis Proven condition assessment method to indicate the health of a transformer. Analogous to pathological testing of humans to detect various bio-logical abnormalities. Expertise is needed for Analysis of dissolved gases in transformer oil. 0 13

14 ' (, ) %, ) * ), ) * + 1,, - " %,. " # / " #. " # # " 0 / " 0 1 ". 23, + ( ( "" # " # "4 # # % 5 14

15 5 ; A % ' " ;.;# B <G /4 = ;.;#.;0 B </4!4 4 = ;.;#.;0.;# <! = ;.; ;.;#.;0.;#.; B <F 14 4 = * ;.'.' A % '.' % 8 4 <>* * *? /14 #388= 1. H2-100 ppm 2. CH4-120 ppm 3. CO ppm 4. CO ppm 5. C2H4-50 ppm 6. C2H6-65 ppm 7. C2H2-35 ppm!4 15

16 + % 5 6 % D C D >* /88 H 6 & % 6 & % &! ' <>* * *? /14 #388= C I ; # $; C I ; $ ; # C! I ; $; # C # I ; 0 $ ; Dornenburg s L1 limit 6 ; ;# ' ; ;# ;0 ( ( < = /4!/ /4 0/! 16

17 6 7 ' <>* * *? /14 #388=!! 6 ' <>* * *? /14 #388= #!6 2$ # / 8.!6.$ #. 8 # /!6 :$ # # 8 #.!6 #$ : ; ; # ; # 7 39: 3 ; 39: #!# 17

18 5 ' 6 6 <>* * *? /14 #388= : 6 # ' : # * ( < 2:3 2# * ( < 2:3 # * ( < # ( # & " ( = 5 ( % 3 3 2# 2# % 3 3 # # % & % : 3 3 2# &! $!/ +- ' <>* 04 /88$ 6 6 # # 8 #.!6 #$. 8 #!6 2$ #. 8 # /!6 :$ > < < # > < < 093 # 093 # > < < #!0 18

19 5 ', # : ' ? # 3 2# 2 3 #!% & $! % $ > 2:3 3 # 3 < 2: # 2 < 033@ 33 3 # 33!1 A ) <>* * *? /14 #388=!5 19

20 % 6 & <>* * *? /14 #388= % 6 I ; J ;# J ' J ;# J ;0 J ; < = >B % 6 G 14, " >B % 6 14, 84,. ' % >B % 6 84, #0!4,. ' ; % >B % 6 F #0!4, >B. 6 B TDCG Rate /Day!8 ' ( A 7 '!% % $ <>* * *? /14 #388= * # % %. % % ## % % #. % % #/ % % % % # % % ' % % #3 0: :3 /: 0:3 #3 # 33 2#2.33 0/:3 /2233 //233 0:2:@ 3 #22B # : # :3 :@ B #2./ #33 2: /03 #4 20

21 ' )!6 $ <>* * *? /14 #388= * #! ' 7 (!% % $./03 2B #22B #3 > #3 ' 6 % % * % + ( ' ' > 23 & * % + ( % 5 % % ( ( 9 ( 9 03 & & C ( 9 9 > 23 ) ( ) ) > 23 ) - 9 C ( 9 ' % 9 03 ) - 9 C ( E ' % 9 > 23 % # % & Fault %CH4 %C2H2 %C2H4 PD D D to to 40 T T to 50 T # 21

22 DUVAL Triangle PD 80 Thermal <300 0 C 80 %CH 4 60 Thermal C 60 %C 2 H H E Discharge (Arcing) Thermal/ Electrical 40 Thermal >700 0 C 20 L E Discharge (Sparking) %C 2 H 2 #! % & ## 22

23 % & #/ + " ( 3 K A 3 3 ; 6 K 7 - <' -.. ) L = #0 23

24 Dissolved Gas Analysis Procedure: Sampling, Labeling Extraction Analysis Interpretation #1 '!' "' ( Toepler pump for gas extraction Nitrogen $ N 2 Oxygen O 2 Water H 2 Carbon monoxide CO Carbon dioxide CO 2 Methane CH 4 Ethane C 2 H 6 Ethylene C 2 H 4 Acetylene C 2 H 2 Propane C 3 H 8 Propene C 3 H 6 #5 24

25 6 injection of the oil Toepler pump gas collecting container gas stream feeder detector amplifier integrator degassing container chromatogram (mercury) rectifying column in a column furnace writer #8 Sampling And Labeling Procedure of oil for DGA test Dry Weather, avoid contamination. Clean, dry, leak proof glass or stainless steel container. Take safety precautions. Sample bottle (Glass/ SS) must be full without any air trap completely sealed and should be properly labeled. /4 25

26 Measurement of Capacitance and Dielectric Dissipation Factor (Power Factor) / % Dielectric Losses are caused by: Conductive losses Polarization losses Partial discharges 2.50E E E E-03 Serial Parallel Sum 5.00E E Parallel circuit Serial circuit I DF : tan δ = I I PF : cos ϕ = I RP CP RP tot = R P 1 ω C P C P R P U DF : tan δ = U U PF : cosϕ = U R C R tot = R ω C S S R S C S / 26

27 ) RBP Resin Bonded Paper RIP Resin Impregnated Paper OIP Oil Impregnated Paper /! ( & % B <C = <>* 04!1= A B ϕ <C = >* * * /184 C>A ' >A C) A 6 C * at 20C ' C? B 0 + G 4.12 M G 4.12 M G./2 M 3 G 4.5/2 M G 4./2 M G 2 M 4!34 #2 M 4 34 #2 M 4 /34 02 M 3 A % <>* 04!1 E = G 4 G 4 G /4 G 4 3 /# 27

28 C) A ) A,B,N humid after storage C dryed // C) A ).).".. DF (f) A, B, C, N Messung bei 20C 6.0% 5.0% 4.0% 3.0% 2.0% 1.0% humid A B C N 0.0% dryed 0.0Hz 50.0Hz 100.0Hz 150.0Hz 200.0Hz 250.0Hz 300.0Hz 350.0Hz 400.0Hz 450.0Hz /0 28

29 humid B %? & dryed /1 ' >A ) Cellulose of the OIP bushings ages particularly at high temperatures. Through ageing the dielectric losses will increase -> increase of the dissipation factor Temperature dependend ageing decomposes the cellulose and produces additional water --> this accellerates the ageing /5 29

30 !!- 7 ' >A ) Removed bushings New bushings C-Tan-Delta Meas. /8 < = /4 ;L <' >A ) = 10,00 [%] 1,00 0, C

31 % <=!4 <!!- 7 ' >A ) = % Tan Delta (f) A, B, C A B C A Removed B Removed C Removed Hz % RVM (Recovery Voltage Measurement) PDC (Polarisation Depolarisation Current) FDS (Frequency Domain Spectroscopy) 0 31

32 A % A ~ & ( + > C + % ) ( 0! % B U I I R R I C C A Dielectric can be modeled by: Capacitance Resistance (losses) Im I C δ I R I Dissipation factor Tangent of angle between sum current I and capacitive current I C Quality of a dielectric ϕ U Re 0# 32

33 Dissipation factor ,1 0,01 0,001 B 9 % B 9 %? B %? σ 0 I ( ω ) = jωc0ε ( ) + χ ( ω ) j + χ ( ω ) U ( ω ) ε 0ω σ 0 + χ ( ω ) C ( ω ) ε ( ω ) ε 0ω tan δ ( ω ) = = = C ( ω ) ε ( ω ) ε ( ) + χ ( ω ) high low moisture of cellulose and aging insulation geometry low high oil conductivity moisture of cellulose, aging high low 0,0001 0,001 0,01 0, Frequency (Hz) F " 9 92C < 2& C ' % % % % % % ( > * % ( % 7 F 0/ A Moisture 4% Moisture 2,5% Moisture 1% Moisture 0,2% Frequency (Hz) 00 33

34 % A B %? DF %@20C Pressboard DF Oil 1pS/m@20C A ~ f/hz f/hz Hot, wet, aged New DF Wet / aged DF %, 43pS@50C DF@50Hz=1,5% DF /15%@20C DF@50Hz=0,23% %, 10pS@20C DF@50Hz=0,4% f/Hz f/hz f/hz Discrimination necessary! 01 % A L $ % L A % U, I Current (na) ( high low oil conductivity i pol (t) T C insulation geometry U c (t) i dep (t) I pol 1 I dep low 0, Time (s) t I pol σ 0 ( t) = C0U 0 + ε ( ) δ ( t) + f ( t) ε 0 moisture of cellulose and aging > * ( ) high 7 " % [ f ( t) f ( t t )] I dep ( t) = C U C 05 34

35 Time Domain: Polarization / Depolarization Currents PDC A % Sample Electrometer 08 ( A % B %? 3 & A % 3&, & ;L B %? 3&, & 9 < 4 = 14 35

36 ? A % B %? Duration / h FDS PDC DIRANA ,1 0,01 0,001 0,0001 & 4 4 N ;L /2# F % % Frequency range / Hz :": % G % " F ( 2C 1 A % B %? 3& <A % = 9 <B %? = ) <A % B %? =, A % 3& ;L 1 36

37 100 Current [na] 1 1 Transformation B 9 % 1000 Time [s] Dissipation factor 1 0,001 0,001 Dissipation factor 1 0,001 0, Frequency [Hz] Frequency [Hz] 1000 DIRANA's patented technique C F " #9 > 392C 09 F ## 2& C 2C 1! A % B %? 3& ID A tan 0.1 b e re c hne t vo n P D C TD F re q u e n z (H z ) 1# 37

38 Instrument = A % >C " Voltage source Current sense 1 A A Instrument A = Current sense 1 Voltage source Current sense 2 Guard Guard C L C HL C H C T C LT C HL LV HV LV MV HV ' +6 4 % ( % ( H 1/ Dissipation factor 1 0,1 0,01 high low moisture and aging of cellulose insulation geometry ; ( & K Sufficient data low high moisture, aging of cellulose high oil 0,001 conductivity low 0,001 0,01 0, Frequency / Hz Moderate Dissipation factor New Freq/Hz 1000 Dissipation factor C Typical: Freq/Hz 1000 Dry transformer or low temperature 0,1 mhz, 2:50 hours Moderate wetness / temperature 1 mhz, 22 min Wet transformer or hot temperature 0,1 Hz, 5 min Dissipation factor Heavily aged Freq/Hz

39 & ) Measurement Data base Temperature Oil XY-model Y Oil Spacers Comparison Barriers X 10 Tangent Delta moisture content, oil conductivity 0,1 0,01 0,0001 0,01 Frequency [Hz] ? Check box: Variable calculated by software Required: Oil temperature Optional: Geometry XY Optional: Oil conductivity 15 39

40 & Observe fitting left of the hump Result: Moisture content 18 B ) ) ) %.. dried wet RIP bushings stored under wet conditions and then dried 54 40

41 B L 5 C TR

42 125/95C & % 1,4/2,1% 270/420 Example: 150 MVA, 7 t cellulose, 70 t Mineral oil, Temperature 40C cellulose W = 3 % 210 kg water 85/65C 2,4/2,9% 441/1105 T+ T Temp. Moisture DP [Ryzhenko, V. Sokolov, V.: Effect of Moisture on Dielectric Withstand Strength of Winding Insulations in Power Transformers. Electrical Stations (Electric Power Plants) No. 9, 1981] Oil 16 ppm 1,1 kg H 2 O Important to know how wet the paper/pressboard is, rather than the oil! 5! ' % IV. Trocknung ) 6 * I ( - % ( % 5# & % 42

43 ? * 3 % Technical data ) 2B /@ 6 % 200 ) I #03822:8.1& I Drying required? 8 5/ B %? $ A % &

44 B %? $ A % & % 5 Moisture in cellulose [%] Tertiary not in use Average 0 FDS HV-LV FDS LV- Tertiary FDS FDS Tertiary- Tank Oilsample RH % Oilsample Karl Fischer mg/kg (Oommen equilibrium) 1mHz-1kHz 51 & > 6 ' % ( % I A 5 % 5 ' * " ' ' +6 4 Moisture in Kraft paper [%] Moisture relative to saturation [%] C 40 C 60 C 80 C 44

45 B %? $ A % &!4 & 7 3 % Decision: on-line drying 58 B %? $ A % &!4 &

46 B %? $ A % & B %? $ A % &

47 C 5 Moisture in cellulose [%] Tertiary not in use Average 0 Dira HV-LV Dira LV- Tertiary Dira Tertiary Tank Oil sample RS Oil sample Oommen 8!? * 3; III. Dielektrische Messverfahren: Praxis Moisture content / % Dielectric methods Moisture in cellulose from dielectric properties (PDC, FDS, Dirana) Oil sampling Moisture in cellulose derived from oil Proved by paper samples Moisture in cellulose by KF titration 0 PDC FDS DIRANA Oil ppm Oil RS KFT Contradictory results 8# 47

48 A % & Dissipation factor f/hz Moisture content Dielectric methods Tangent delta at 25C aging byproducts appear as water Dirana gives 2,9% instead of 3,8/4% ) 2B : * A /* J 2B /:" 3": A 8 " ( 2033% * 8K #2 PDC FDS DIRANA Oil ppm Oil RS KFT 8/ Dissipation factor ,1 0,01 ) 2,1% aged 1,2% aged 2,0% new 0,8% new 0,001 1E-04 0,001 0,01 0, Frequency / Hz Conductive aging by-products behave similar to water (HIGH TAN DELTA) Overestimated moisture content without compensation DIRANA Compensates for this influence 80 48

49 " DF Very different DF curves 0716b / T Same moisture content 0,4 % / 0,4% T b Different oil conductivity 0,94 ps/m / 0,06 ps/m PI would undervalue 0716b Freq/Hz 1000 Stop at 1 or 2 mhz would make analysis impossible 81? *!3 " III. Dielektrische Messverfahren: Praxis.:3) I " & I ) #33. ' % 85 49

50 III. Dielektrische Messverfahren: Praxis? *!3 & C Dissipation factor T11 & 7 ( T13 T f/hz ) ML N 2 3"/ 3"3/ ( M% * 8N + #.L %.:L # 3": 3"# 0 3". 3"30 88? * #3 % >C " C The test was carried out on a Shunt reactor The W.C result on direct paper sample was available for comparison DIRANA result (1.1%), Direct sample measurement (1%)

51 C On 63 MVAR, 400kV Shunt Reactor at a Utility DIRANA estimation 1.1% KFT sample 1% 4 Impedance Measurement 4 51

52 > & Winding Resistance Static Measurement Winding Resistance Dynamic Measurement Short Circuit Reactance (Stray Reactance) FRSL Measurement 4! &? C 7 Static Resistance Measurement = All internal contacts: Diverter switch contacts + Tapselector contacts + Connecting leads + Winding Resistance 4 # 52

53 " 7? 4 / /4 4 & 7 Resistance [mω] 285,00 280,00 275,00 270,00 265,00 260,00 255,00 250,00 245,00 240,00 235, KEMA OMICRON 1 21 Ref. Temp. OMICRON 21 1 Ref. Temp. Tap position

54 4 4 & 7 4 $4-7 E 3A R L1 (referred to 20 C) mohm R L R L RL Taps & 7 4 $ A R L2 (referred to 20 ) mohm R L R L R L Taps

55 4 4 & 7 4 $4-7 3A R L3 (referred to 20 ) mohm R L R L R L3K Taps 4 8 B? 4 55

56 C E 3A C Resistance L1 Resistance [mω] Factory Measurement OMICRON 1 19 OMICRON 19 1 Taps % C E 3A ;? * O E A P 3O % ' " P Resistance Differenz L1 Up-Down (Delta R) / R [%] Taps Resistance Differenz L1 Up-Down Before repair 2,0 1,5 (Delta R) / R [%] 1,0 0,5 0,0-0,5-1,0 After repair -1,5-2, Taps 56

57 > & Winding Resistance Static Measurement Winding Resistance Dynamic Measurement Short Circuit Reactance (Stray Reactance) FRSL Measurement!? A Slope A α 1 3 Ripple = Diverter switch switches to the first transition resistor 2 = Both transition resistors are in parallel 3 = Final contact of the diverter contact B is reached 4 = Current control regulates the test current to the rated test current again # 57

58 C %? 6 <4 4 & 7 = Ripple 2.5% 2.0% 1.5% 1.0% 0.5% A UP A DOWN B UP B DOWN C UP C DOWN 0.0% Taps /? %? 6 <4 4 & 7 = Slope 0.0A/s -0.1A/s -0.2A/s -0.3A/s -0.4A/s -0.5A/s -0.6A/s -0.7A/s -0.8A/s -0.9A/s Taps A UP A DOWN B UP B DOWN C UP C DOWN 0 58

59 C %? 5.5% Ripple 5.0% 4.5% 4.0% 3.5% A UP A DOWN B UP B DOWN C UP C DOWN 3.0% Taps 1 %? 5 59

60 > & Winding Resistance Static Measurement Winding Resistance Dynamic Measurement Short Circuit Reactance (Stray Reactance) FRSL Measurement 8? > Forces L sc is getting larger with wider stray channel Stray Flux LV Winding R sc L sc 220kV HV Winding Wicklung HV LV 4 60

61 > & Winding Resistance Static Measurement Winding Resistance Dynamic Measurement Short Circuit Reactance (Stray Reactance) FRSL Measurement C <= R sc X sc Z sc R dc ac represents the losses resistance of the of stray the flux windings R dc 61

62 A? < = B HV winding Induced currents are compensated LV winding! A?? HV Winding B Additional losses by induced currents LV Winding R Winding is unchanged Ratio is unchanged # 62

63 ! A R(f) 4.5 Ohm 4.0 Ohm 3.5 Ohm 3.0 Ohm 2.5 Ohm 2.0 Ohm 1.5 Ohm 1.0 Ohm 0.5 Ohm 0.0 Ohm Frequenz (Hz) A B C / B A R(f) mohm A B C Frequenz [Hz] 0 63

64 ( ' 1-3 L ; 3.. E 5 64

65 8!4 65

66 ! A C > ( % >? ; C6 *! 66

67 "!"# $%&! ' )(! * % + #, #-! #. ( / 01 #2 43) *# 45/ %1 # 46 */ 87 - & * 9:, 1 % ;/ "! $. % - *! < 83) %& = > # * 1-9!!C! /,! D!! A % % >* A % <A % = ( L =!# 67

68 ', ( -, *,? L, %,!/ % * A ) J C!0 68

69 & A % 3 3,, 7,,,, F F Q!1 A % % >* A % > 7 E % % ( % = " ( % % = ( % ( +% " % (, % % ( ' % F F % ( 9!5 69

70 A % % >* A % * + 7 E % % ( % = " ( % % = ( ' % F ( 9 +% " (, % % ( ' % F F " " % ( 9!8 A % > * + 7 Internal PD has hystersis External corona has normally no hysteresis IEC #4 70

71 A % & K Non-destructive test method to: detect critical defects localize defects assess the risk # A % Surface discharges appearing at the boundary of different insulation materials Corona discharge occuring in gaseous dielectrics in the presence of inhomogenous fields Internal discharges occuring in voids or cavities within solid or liquid dielectrics Continuous impact of discharges in solid dielectrics forming discharge channels (treeing) in organic materials # 71

72 A % a) corona discharge b) surface discharges c) discharge in laminated material d) cavity discharge e) treeing #! * A * ## 72

73 * A * #/ A L * % Needle on HV #0 73

74 A % 6 PD are in general a consequence of local electrical stress concentrations in the insulation or on the surface of the insulation PD generate electromagnetic signals PD are often accompanied by emission of sound, light, heat, and chemical reactions #1 % A %, <% 6 =,* < = >* 04 14,,E ;B #5 74

75 % 6-6 #8 % 6, A + -,, C >* >* * * /4 75

76 % 6 (, * +,, ) &, ' 3? -, 9, / * 9 % A 2C S U 1(t) U t(t) ε r CP /2 C F ε 0 C P /2 U z 2C S U L -U L t U' 1(t) -U z B A I s (t) I 3 (t) C S I 2 (t) I 1 (t) U t C P U 1 B C F R 1 I 1 (t) S q = U. 1 C F q = i1( t). dt t / 76

77 > A % 3A A A % A % <>= R C <% = A % * <* = A % A ( <A = A % C C <C= 1 I = T 1 D = T i i q i 2 q i E = q i. u i i 1 P = q i. u i T i /! A % > (IEC 60270) /# 77

78 A % > (IEC 60270) // C>7 A %? <" ) = /0 78

79 A %? ) B /1 A % > Z U Calibrator C 0 I(t) A C t C K s k. q max = S max U 0 B U m Z m Amp. Filter M Measuring Impedance C c /5 79

80 & % Transformer under test I PD Coupling capacitor Testing transformer Fault (discharge) PD /8 A % & ( Coupling capacitor Testing transformer Faraday cage Test object PD instrument 04 80

81 " B 3 ; 3 ( S 3 3 ' 3 0 % A % Analogue PD measuring instrument PD systems Digital PD measuring instrument 0 81

82 A % & 0! T% T A % & 0# 82

83 & % B 0/ A, 3 % Amplitude Phase 00 83

84 A % A Source: J. Fuhr, Procedure for Identification 01 and Localization of PD, IEEE Transactions 2005 A % A Source: J. Fuhr, Procedure for Identification and Localization of PD, IEEE Transactions

85 A % A 6 PD in a slot PD in the winding head (IEC ) ! C % * - " <808= 14 85

86 A % A & A B A 1 A % A A 6 >? 1 86

87 A % MPD600 1! ;7? >* # 87

88 ) 1/ A!- 7 $!- 7 B 10 88

89 A % 11 ;7? >*

90 A % 18?

91 C > 5 U L & A %

92 Inner PD source in L1 in 3PARD 3PARD L2 L1 Inner PD Source L1>L2>L3 Inner PD Source in L1 L2 L3 L3 L1 timeframe 1 µs 3PARD = Three Phase Amplitude Relation Diagram 5 5! Outer noise in 3PARD 3PARD L2 L1 Outer Noise L1 L2 L3 Outer Noise L2 L3 L3 L1 timeframe 1 µs 3PARD = Three Phase Amplitude Relation Diagram 6 5# 92

93 !A C%! A C % 3PARD = Three Phase Amplitude Relation Diagram 5/!A C% C 3 Superposition of several sources 3PARD-Clustering Re-Transformation: Noise Cleaned-Up Fingerprint 50 93

94 & C 30 MVA Transformer, 115 kv / 11.3 kv 51 Statistical Noise & C 30 MVA Transformer, 115 kv / 11.3 kv External Disturbance PD Fault 55 94

95 A % & 3 Channels simultaneous measurement 58 A % & 84 95

96 A % &,! A C% 8 A % & 3 A 8 96

97 A % &, B ( 8! % A %, <% 6 =,' < E 7 =,* < = >* 04 14,,E ;B 8# 97

98 & % % - 9 > ( -? 9 8/ &, > 3,? S?, C 9, 80 98

99 ( &, 9, A A % < =, A,, & > !"# ""$% # #$ #&% " " "! "&". sensor 85 99

100 > + * 3 > S ( A % Block diagram of the instrumentation circuit sensor Pre-Amp filter Amp threshold counter Digital scope Frequency analyzer DAS & PC oscilloscope X-y recorder

101 The AE signals reaching the tank wall of the transformer is detected by the AE sensor. The sensor is a piezo-electric transducer, which converts the mechanical/acoustic waves into electrical signals They are sensitive to the transient acoustic signals resulting from PD, but are insensitive to the vibration & general noise. 4! " # $ $ % $ & '"!%# # #! %$ & '!$ $ # %$ & ($ $ & 4 101

102 pressboard Discharge source Sensor B Sensor A Steel tank Pre amp Pre amp filter Power Amp filter Power Amp Pulse counter Signal averager Trigger processor Pulse\ counter 4!!! " " # $ % "&! ' #% "! ( #! " ) & & Channel A t Channel B 4 # 102

103 Bushing Pre-Amp Filter A.D.C D.A.S Transformer test tank oil Discharge points PC Monitor Keyboard 4 /

104

105 A %, 0*,* (,' 4 8 Source: ABB A % 5 & % C % E E t t d E E t t d E E t t d 1 1 Direction of PD Source 4 Source: ABB 105

106 & A A % Coolers Coolers Cabinets Back Left side Front Right side Source: ABB A % Signal Source Source: ABB 106

107 % A %, <% 6 =,' < E 7 =,* < = >* 04 14,,E ;B! E ;B & Detection of the electromagnetic field with electrical field probes (planes) Frequency range: MHz Wafe lengths: m # 107

108 ? E ;B & / E ;B &? 0 108

109 E ;B & 6 >? Void in an Insulator Moving Particles 1 % 9 % 6 * & & E ;B & 5 109

110 % % 6, A + -,, C >* >* * * 4 110

111 % 6 (, * +,, ) &, ' 3? -, 9, * &, A % 7 C ), + * + <7 > = 111

112 * &, C -, % ) A %,, "! ( * &, * + 7 3V3 E ;B, & S & 9, ( A % +,, 9 # 112

113 E ;B & % A % *,, A % C? A % 9? 33 / E ;B &? L, % 9, %? A A 9, A % 3 3 E ;B 0 113

114 E ;B & % -, C? 9, (,? 1 E ;B &, 7, 4, & * A %?,, ' 9!4 4!4 4 4 & ;L >, A %

115 E ;B & (, A E ;B,, 9, 3 6 >? 9 * 8 %, & - +, % 6,, *,? L,, * 3, E ;B, > )?!4 115

116 % A B E C " " ( W? >?! Structure of Cellulose Decomposition products of Cellulose! 116

117 >? A Degree of Polymerization (DP): Source: Thomas A.Prevost EHV Weidmann Industries, Inc 2005!! Solid Insulation: The Life Line of Transformer!# 117

118 >? A Solid Insulation: Cellulose Degradation: Source:GE Energy RVP-AI 2005!/ Solid Insulation: Cellulose Degradation: Furan Analysis ASTM D 5837 DP Analysis ASTM D 4242 Source: Thomas A.Prevost EHV Weidmann Industries, Inc 2005!0 118

119 B 5 ( 5-hydroxylmethyl-2-furfural (5HMF) furfuryl alcohol (2FOL) 2-furfural (2FAL) 2-acetyl furan (2ACF) 5-methyl-2-furfural (5MEF)!1 B &''()*+* &''() &'()*+* &(.)'(/,&')!.+)0./- + &'# ( #* 2!.+)&''()*+* + & + + & + + &''),'')() +)- 2+*3!.+)&''()*+*!5 119

120 B Cigré Proceedings WG D (formerly WG 15-01): degree of polymerisation, count of the molecular links furan count in ppm!8 B #4 120

121 >? A # % A 7 C A ( B!! <% A 3% A L = # 121

122 B <B H ;= Example: damaged transformer B X $ - Y < = / ! 3 3!## 4 4 / #5 # DP value in accordance with Cigré Proceedings = 289 #! A 3 E? -., - 7 ' ' ( M#5 7 N( 9' - " % M#5 7 N F " 9 9 % % ## 122

123 ? % A >* A #/4 * ) '.#.#9 3 <B ( = 9? & % /5!1 B $ 9 + ; A ( 9 <;A ( = + L ;A ( #/ - Z #0 123