Generator Overhauling

8/20/2019 Generator Overhauling

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Overhauls

Presented by

Abhilash Chandra Aron

Consultant, Turbogenerators


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General

Define scope of mandatory works.

Define possible areas of additional and unforseen work actiities.

!ork out list of spares and consumables that shall or may be re"uired. This list to be as e#haustie as possible.

Consult $%&' ( contractor well before.

)chedule as many actiities in parallel as possible. )pecial task group may be made to gie emphasis to longest cycle actiity.

!ithin the organi*ation, create and deelop specialists for main products. They should not only assist in oerhauls or

operational emergencies,but also work for improements in + - areas of the product.

C/T&/A 0+ +1&%A2') /nitial /nspection3 Dictated by stator end winding and stator slot support systems. )ynthetic and insulating material tend

to flow4creep5 under pressure and temperature during initial period. Deficiencies of manuf. assembly or design can be corrected. )tart up stresses3 &ffects of e#pansion, friction on winding and insulation due to thermal centrifugal force cycles.

)pecial ibratory forces arising when passing through natural fre"uencies of components.

-aterial fatigue, especially of rotating parts resulting from centrifugal force cycles.

6ormal recommendations for inspection interals apply to normal operation without any ma7or disturbances.

+1&%A2') 1D&! &C+--&6DAT/+6)

/6/T/A', )%+T, /6T&-&D/AT& A6D -A/6 /6)P&CT/+6)

TEQIV 8 91 . T1 : 92 . T2 : n . T3 9;, T; 0ACT+(T/-&, T> 0ACT+( T/-& < &'AT/6G T+

)TAT 2P

?@ -1A TG3 9; 8 ;., 9= 8 .B, T> 8 = @ -1A TG3 9; 8 ., 9= 8 .>, T> 8 ;

=B -1A TG3 9; 8 .E, 9= 8 .;, T> 8 ; B -1A TG3 9; 8 .F, 9= 8 .;, T> 8 B

0+''+!/6G '&AD T+ &A' /6)P63 0A2'T )6C%+6/)/6G

C'+)& /6 ))T&- 0A2'T)

A)6C%+6+2) +P&AT/+6

%/G% 26$A'A6C&D '+AD)

A')+ 0+''+!/6G 0ACT+)3

!&A(D&T&/+AT/+6 +0 C+-P+6&6T) + 266/6G $&%A1/+2.

'+AD &J&CT/+6), +T+ 0A2'T)...


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OVERHAULS - 3

C%A6G& /6 C++'A6T 0'+! AT&).

0+2'/6G /6 A/ C++'&D G&6&AT+).

%D+G&6 + !AT& '&A9).

)%A0T /6)2'AT/+6 D&T&/+AT/+6. &C+--&6DAT/+6) 0+ /6)P&CT/+6)

TEQUIV < /6/T/A'3 ; < = T%+2 %)

TEQUIV < -A/63 H < @ T%+2 %) +6& + -+& )%+T /6T&-&D/AT&

/6)P&CT/+6 $& D+6& $&T!. = -A/6.


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OVERHAULS - 4 /6/T/A' -AJ+ 6&&D +T+ &-+1A' &GAD'&)) +0 A$+1&, 0+ ?=B -1A3

-/6+ /6)P&CT/+6 /6 = ).

-&D/2- /6)P&CT/+6 /6 B ).-AJ+ /6)P&CT/+6 /6 ; ).

0+ =B -1A /6 >, @, ;= &A)

C%&C9) 0+ /6/T/A' +T%& /6)P6. T+$& AG&&D !/T% -A620ACT2&

26C%A%A < ;3 H@> T/P) $&T ;E


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0 10 20 30 40 50 60 70

ACTUAL OPERATING HRS.: T (10 )3

90

80

70

60

50

40

30

20

10

FIRST INSPECTION

3

FIRST MAOR INSPECTION

TIME (!EARS)

B

"#$

2

4

6

8

2

4

6

8

10

12

10

8

6

4

2

100 STARTS%!R 300 ST%!R

10ST%!R

A. C. ARON

&UI'.

OPER.

RS.

T*+,

10 H-

A

10

12



OVERHAULS

;st /6)P&CT/+63 ; < = T%+2 %).

)2$)&I2&6T3 H < @ T%+2 %).

-/6+ /6)P&CT/+6) /6 $&T!&&6.

DATA $&0+& )%2T D+!6.

CA)& +0 6A+A +T+ < '+! /

D&T&CT&D A0T& +T+ &/6)&T/+6.

DATA A0T& &+''/6G.



BEFORE OVERHAUL

$&A/6G 1/$AT/+6) $& &C+D&D.

C%&C9 $&A/6G )%A0T )&A' /6)2'N.

+T+ !DG. /-P&D&6C& &)/)TA6C&.

)TAT+ +T+ !/6D/6G / -&A)2&D.

!/6D/6G T&-P, !AT& 0'+!) &C+D&D.

GA) '&A9) )&A'



DURING OVERHAUL

INITIAL AND MAJOR C+& C+6D/T/+6 &'C/D C+& T&)T.

/0 0A2'T C2&6TK ? ; mA , A6D /0 A6 C+&

DA-AG& 1/)2A'' )&&6, A6D ( + &PA/&D

&TC., P+!& C+& '+)) T&)T T+ $& D+6&.

)TAT+ &6D !/6D/6G )2PP+T ))T&- A6D

+1&%A6G C+6D/T/+6.

)TAT+ !/6D/6G /6)2'AT/+6 C+6D/T/+6. )TAT+ !/6D/6G /K A6D '&A9AG&).



DURING OVERHAUL - 2

INITIAL AND MAJOR )TAT+ !&DG& T/G%T6&)).

'&A9AG& T&)T +0 %D+G&6 ))T&-.

)'/P /6G) $2)%G&A. C%&C9 A'' 2$$& GA)9&T).

'&A9AG& T&)T) +6 )TAT+ !/6D/6G, !AT&

))T&-, 0/'T&) C'&A6/6G.

$&A/6G '/6& $+D /6)P&CT/+6.



DURING OVERHAUL - 3

INITIAL AND MAJOR +T+ &TA/6/6G /6G )20AC&).

C%&C9 /0 +T+ )%A0T /) -AG6&T/)&D.

26 +2T C%&C9) +6 +T+. C%&C9 &-+1&D +T+ 1/)2A''.

+T+ !/6D/6G /K.

+T+ $&A/6G )&A') J+26A'). P2G& T&)T)K +6 +T+.

C%&C9 +T+ 0A6) 1/)2A''.



DURING OVERHAUL - 4 INITIAL AND MAJOR

+T+ C.C. $+'T) 0+ '&A9AG&).

A'' C++'&) T+ $& C'&A6&D C! )/D&.

C%&C9 $&A/6G A6D )&A') /6)2'AT/+6. $&A/6G C'&AA6C&), $A$$/T, A'' +/'

CATC%&), JAC9/6G +/' '/0T, TCs ( TDs.

)P%&/CA' )20AC&) +0 $&A/6G.

)'/D/6G C+6TACT 0AC&) +0 )&A' /6G), )&A'$+D, )%A0T )&A' C'&AA6C&).


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DURING OVERHAUL -

INITIAL AND MAJOR C'&A6'/6&)) !%&6 $+L/6G 2P.

'&A9AG&) /6 C+-P'&T& %= GA) ))T&-.

026CT/+6 +0 T+TA' )&A' +/' ))T&-. )&A' +/' 0'+!) AT 02'' M&+ )P&&D

C%&C9 $&A/6G 1AP+2 &L%A2)T&).

A'' T&-P&AT2& GA2G&) A'A-).

'/I2/D '&1&' A'A- )!/TC%&) &TC.

C+6D/T/+6 +0 G+26D/6G $2)%&).


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!ra"#$"es RE!LIES TO %UERRIES B& BHEL IN '()

$ased on = replies to "ueries following

maintenance planning periods obtained3

otor, )tator, Au#iliary systems and$earings < for each < ;B days

%ydrogen shaft seals > days

)haft insulation and earthing B days $rush gear and slip rings = days


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!ra"#$"es - 2

RE!LIES TO %UERRIES B& BHEL IN '()

2sual actiities3)tator wedges tightness

)tator core tightness, core flu# test

%ydraulic tests on stator wdg.,coolers

Purge tests on rotor and gastightness

/ on stator,rotor,bearing insulationGas tightness test on complete m(c

+CC )CC after resynchroni*ation


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!ra"#$"es-Fre*ue+", . Ma$+#e+a+"eRE!LIES TO %UERRIES B& BHEL IN '()

$earing /nspn.E


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Me##ur ' / Overhaul s"0e

Total running hours upto Aug ;> 3 >H,F Preious -a7or oerhaul done 3 6o ;E

6umber of start ups so far =>E

)ince last oerhaul F 'P rear bearing ibration was high3 >@%, =B1

%igh eccentricity problem3 >E -icron at start up

and later on load ;; -icrons. cessie bearing clearances and change in

catenary oer period of time was reported


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Me##ur ' / Overhaul s"0e - 2 $earing ; liner replacement, cutting of F nos.

sei*ed cap nuts on %P /P.

Generator rotor replacement by the spare rotor

< T6&$ decision because of its low /. 'P rotor =th,=th stage, /P =>rd stage lacing wire

old bra*ing was debra*ed and rebra*ed. $lades

natural fre"uency check performed.

-inor works on front pedestal, -+P, 1ales,

&7ector and cam shaft assembly were done.


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Me##ur ' / Overhaul s"0e - 3 )tator 3 >N wedges found loose


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Me##ur I / 10le#$+ a,s2+ 1a0$#al verhaul / 's# Au # '4#h O"# '((3

2nit tripped < on barring gear F )lip ring machining incl. grooe cutting, dismantling started.

;= 'ifting of top 'P casing. ;H Generator rotor threaded out. ;B 'ifting of top /P casing. ;E 'ifting of top %P casing == Dismantling works completed. > 'P bo# up >= )tator slot wedge tightening.


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Me##ur I "0le#$+ a,s -2

H; /P bo# up HH Generator rotor threaded in. B %P bo# up

@ Generator re


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Ne,val$-4 2'5 M6 / S"0e

OVERHAUL IN O1T - DE1 '((4

'P module, Generator, Turbine ales, C% 61,

seromotors, Turning gear and -+P bearings,

-ain %% strainers, ollcheck $umpcheck of

%P and /P, %anger supports, Goerning rack, 'P$yepass rack mechanical components only.

'ub oil coolers tank < filters < pumps, Coolers


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Ne,val$-4 2'5 M6 / S"0e - 2 eplacement of rubber grommets around

teflon tubes of winding in stator. 4&rection

point < pending from $%&' side5

After dismantling, in 'P turbine '%) %)clearances found une"ual. These were

corrected by shifting 'P inner outer casing

unning hours upto oerhaul 3 ;E,@ 6umber of trips upto oerhaul =F

After o(haul3 All bearings ibrations reduced


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Ne,val$-4 2'5 M6 / S"0e - 3Ge+era#r

otor purge test, gas tightness < leak in

small CC bolts < nuts tightened. DPT of fan

blades and retaining rings done. otor

7ournals were polished.

FBN stator wedges loose < retightened.

H= swollen teflon tubes rubber grometsreplaced without opening nose 7oints.

)tator oerhang was in7ected with glue.


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Ne,val$-4 2'5 M6 / 10le#$+

)et tripped.

E )toppage of barring gear.

;; Generator rotor threaded out. ;= Dismantling of 'P.

;E Purge test on generator rotor.

>; 'P $o#ed up. HB Generator rotor threaded in.

BH Generator assembly completed.


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Ne,val$-4 2'5 M6/10le#$+-2

@F +il flushing started. F +il flushing completed.

$arring gear operation started.

F )et steam rolled. E )ynchroni*ed

E> Achiees full load smoothly.

$arring gear date got delayed by => days 3 )tatorworks held rotor threading by ;B days. 'P<Generator holes were reamed for ;= days Q


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AFSHA CLASS 5

G++D $& Q

T+ A'' +0 2

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Generator Overhauling