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Performance Analysis 2008
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Performance Analysis 2008
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Performance Analysis 2008
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Performance Analysis 2008
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Performance Analysis 2008
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Performance Analysis 2008
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Performance Analysis 2008
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Performance Analysis 2008
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Performance Analysis 2008
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Performance Analysis 2008
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Performance Analysis 2008
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Performance Analysis 2008
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Performance Analysis 2008
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Performance Analysis 2008
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FORCED OUTAGECY WISE BREAK UP (No. / %)
Heads Cal Year 2006 Cal Year 2007 Cal Year 2008
Pld outage 6 / 5.75 7 / 6.10 6 / 6.09
Grid Rest . +
Dist
1 / 0.002 0 / 0.000 0 / 0.000
Blr Aux 2 / 0.04 6 / 0.14 3 / 0.04
Turb Aux 4 / 0.23 6 / 0.09 2 / 0.23
Elect Aux 7 / 0.34 7 / 0.05 23 / 0.25
BTL 15 / 0.70 27 / 1.25 33 / 1.51
C&I 1 / 0.01 15 / 0.08 8 / 0.02Others 2 / 0.01 3 / 0.01 9 / 0.21
Fd outage 32 / 1.33 64 / 1.63 78 / 2.26
Total Outage 38 / 7.07 71 / 7.73 84 / 8.35
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Action Plan to reduce Forced Outages
CAUSE OF TRIPPING
• U # III : Leakage from
LHS Eco coil no.32
header joint
• Root Cause: Weldfailure.
ACTION PLAN
• Proper marking andrecord of defective
joints afterradiograph
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Action Plan to reduce Forced Outages
CAUSE OF TRIPPING
• U # III : Leakage from
LHS SCW T-1&2
above re-heater
regulating stage
• Root Cause:
Attachment weld
failure, sample sent to
R&D.
ACTION PLAN
• Exhaustive DPT andchecking of attachment welds.
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Action Plan to reduce Forced Outages
CAUSE OF TRIPPING
• U # VII : Leakage from
water wall (LHS ) tube
no -12 towards rear
from scaffold door at anelevation of 8.5 mt
• Root Cause: Ash led air
erosion due to gap
between LHS & S-
Panel WW.
ACTION PLAN
• Sealing of gapsbetween “S” paneland vertical wall
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Action Plan to reduce Forced Outages
CAUSE OF TRIPPING
• U # VII : both ID & FD
fans tripped on “Post
purge fan trip”
protection and unittripped on “both FD
fans OFF”.
• Root Cause: Defective
input cards EB02 in
CRB01 panel
ACTION PLAN
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Action Plan to reduce Forced Outages
CAUSE OF TRIPPING
• U # VIII : Unit was de-
synchronised to attend
HRH ERV (no. 23)
passing, manualisolating valve was also
passing.
ACTION PLAN
• New ERV wasreplaced with newone.
• Servicing of manualisolating valve everyoverhaul.
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Action Plan to reduce Forced Outages
CAUSE OF TRIPPING
• U # VIII : Leakage
from water wall S-
panel area front side
tube no1 from LHS atan elevation of 8.5 mt
near scaffold door
• Root Cause:
Attachment weld
failure.
ACTION PLAN
• Exhaustive DPT andchecking of attachment welds.
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Action Plan to reduce Forced Outages
CAUSE OF TRIPPING
• U # X : Leakage from
from water wall (front
side ) tube no -1
towards right fromWWSB No.-45. EL-46
mt
• Root Cause: Shop weld
failure
ACTION PLAN
• Radiography of shop/erection jointsin phased mannerduring overhaul.
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Action Plan to reduce Forced Outages
CAUSE OF TRIPPING
• U # X : Unit tripped on “ GT
WTI operated” due to the
actuation of “GT Cooling fan
supply change over fault” relay
• Root Cause: Over current relay
operation of 415 V in both
incomers of ACDB due to the
circulating current flown while
paralleling of both
transformers(11/0.4 KV)
ACTION PLAN
• Review of over-current relaysetting and timedelay.
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Action Plan to reduce Forced Outages
CAUSE OF TRIPPING
• U # X : Leakage from
ECO lower bank
bottom, vertical joint of
inner most tube of coilno 1 from LHS at an
elevation of 48 mt.
Root Cause: Erection
weld failure.
ACTION PLAN
• Radiography of shop/erection jointsin phased mannerduring overhaul.
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Action Plan to reduce Forced Outages
CAUSE OFTRIPPING
• U # III : Tube
leakage in Re-heater
Regulating stage
Coil no. 80 RHS
bottom centre bend
• Root Cause: Flue
Gas erosion .
ACTION PLAN
• Inspection andthickness survey
of bends at all foursides and middletop and bottom.
• Lifting of 24 coils
every year toinspect middlebends of all 288coils.
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Action Plan to reduce Forced Outages
CAUSE OFTRIPPING
• U # VI : Tube
leakage in Re-heater
Regulating stage
Coil no. 31 LHS
bottom extreme
bend.
• Root Cause: Flue
Gas erosion .
ACTION PLAN
• Inspection andthickness survey
of bends at all foursides and middletop and bottom.
• Lifting of 24 coils
every year toinspect middlebends of all 288coils.
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Action Plan to reduce Forced Outages
CAUSE OF TRIPPING
• U # IX : . Turbine tripped on
„Cold gas temperature high‟
protection. Both TDBFPs
tripped. MDBFP came on autobut it tripped on protection.
Boiler tripped on Drum level
very low protection
• Root Cause: Air locking in the
TG ECW system
ACTION PLAN
• Presence of NRV betweenECW make uptank and
suction header.shall bereviewed;matter will bereferred to OS-
Engg.
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Action Plan to reduce Forced Outages
CAUSE OF TRIPPING• U # X : Unit tripped on
“Loss of All Fuel”
protection.
• Root Cause: Tripping of PA fan-10B on local EPB
operation
ACTION PLAN
• EPBs of all PA, FD,ID fans were checkedfor integrity of fixtures.
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Action Plan to reduce Forced Outages
CAUSE OF
TRIPPING
• U # II Tripped on
“Loss of Excitation”
Root Cause: Reason
could not be
established
ACTION PLAN
Thorough checking
of both the DVR
and control/Power
circuit of
Excitation system
indicates noabnormality in the
system.
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Action Plan to reduce Forced Outages
CAUSE OF
TRIPPING
• U # V : Tube
leakage in Re-heater
Regulating stage
Coil no. 144 LHS
bottom extreme
bend.
• Root Cause: Flue
Gas erosion .
ACTION PLAN
• Inspection and
thickness surveyof bends at all four
sides and middle
top and bottom.
• Lifting of ~50
coils to inspect all
288 coils.
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Action Plan to reduce Forced Outages
CAUSE OF TRIPPING
• U # IV : . Tube leakage
in Water Wall S-panel
Rear panel tube T161
• Root Cause: Impact of
falling clinker.
ACTION PLAN
• Air distributionplates on RHS(Cor-1,5,4 &8)were inspectedand damagedplates wererectified.
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Action Plan to reduce Forced Outages
CAUSE OF TRIPPING• U # VII : Unit tripped on
“Rotor E/F stage 2”
protection.
• Root Cause: Rotor E/Fprotection Circuit
problem
ACTION PLAN
• Rotor E/F stage 2protection bothauxiliary relay shallbe connected to
RA7A panel DCcircuit alone.Proposal has beensent to OS-CC forconcurrence and
approval.
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Tripping Analysis
CAUSE OF TRIPPING
• U # V Tripped on
“Flame failure”
Root Cause:
C&I Control card
failure.
ACTION PLAN
• The defective
NPM12 Card was
replaced with
another new
NPM12 card.
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Tripping Analysis
CAUSE OF TRIPPING
• U # II Tripped on
“Loss of Excitation”
Root Cause:
Defective cards in
DVR UM.
ACTION PLAN
• The defectives
Cards were
replaced and the
excitation system
changed over from
Stand-by to main .
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Tripping Analysis
CAUSE OF TRIPPING
• U # V Tripped on
“Cond. Vacuum fail”
protection
Root Cause:
Water particles in the
vacuum switches
ACTION PLAN
• All the vacuum
switches were
cleaned, recalibrated ,fixed back and put
into service after
wrapping all the
switches withsuitable polythene
covers.
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Tripping Analysis
CAUSE OF
TRIPPING
• U # V Trippedon “Cond.
Vacuum fail”protection
Root Cause:
Micro
switchesdevelopedproblems dueto presence of water particles
ACTION PLAN
• The vacuum switches werereplaced with brand new Ashcroftmake vacuum switches. All
associated cables and protectionblock were checked for the secondtime and found normal. 2 out of 3logic was also checked and foundnormal.
• In future, any switch, withpresence water particles, shall bedried and cleaned. If required, thesame shall be replaced
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Tripping AnalysisCAUSE OF TRIPPING
• U # X Tripped on“Loss of all fuel”
Root Cause:
Sudden rupture of strainer change overvalve flange gasket of HFO supply line inHFO control station atBoiler firing floorcausing oil splashingover leading to firebreak out.
ACTION PLAN
• It shall be alwaysensured to replace thegaskets in HFO
system with betterquality gaskets.
• Proper control of HFO pressure shallbe ensured while
taking oil guns intoservice.
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Tripping Analysis
CAUSE OF TRIPPING
• U # IX stopped due tohigh TG Vibration
Root Cause: • Clearances of LP
front gland box washigher probably
because of higherclearances of horizontal keys of LPT front gland box
ACTION PLAN
• The gland box of LPfront was centered.
• Horizontal keys were
corrected after built-upand machining.
• TG Brg 3 was inspectedas a preventivemeasure.
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Tripping Analysis
CAUSE OF
TRIPPING• Station Black-out
Root Cause:
a). Arcing in V-
J#4 R phasebreaker ; b) Busbar differentialprotection for bussection-I,did notoperate eventhough the relaysettings were asper design.
ACTION PLAN
• Measures to prevent arcing in400KV breakers. Matter has beentaken up with M/S CGL (OEM) tostudy the reason for initiation of arc and suggest remedies forpreventing the same.
• Reviewing of current settings forstart relay and differential relaywhich activate the bus barprotection. Communication in thisregard has been sent to GM(PE-Elect.) and M/s ABB
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Tripping Analysis
CAUSE OF TRIPPING
• U#9 : Water wall Tube
leakage
Root Cause:
• Attachment weldfailure.
ACTION PLAN
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Tripping Analysis
CAUSE OF TRIPPING
• U#4 : Economiser
Tube leakage
Root Cause:
• Maintenance weldDefect.
ACTION PLAN
• Proper marking and
record of defective
joints after
radiograph beingdone.
• Welder wise defect
rate being
maintained for
control.
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Tripping Analysis
CAUSE OF TRIPPING
• U#1 : Unit tripped on
“Furnace Pr. Low” as all
running RCF came to
minimum loading.Root Cause:
• Momentary disturbance
in “Node-2” 24 V supply.
ACTION PLAN
• Supply block for“Node-2” has beenreplaced.
• Controllers‟ supply for RC Feeder will besegregated in 03different panel (02RCF from each panel.)in next overhaul byC&I department.
i i A i
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Tripping Analysis
CAUSE OF TRIPPING
• U#1 : Unit tripped on
“GT winding Temp
high”.
Root Cause: • Power cable joint of
main supply to GTMB
failed and caught fire,
due to which GT
protection control
cables got damaged.
ACTION PLAN
• During Unit O/H
inspection of cable tray in
GT yard area will be done,
joints will be identified andnew cables will be laid.
• b) Control cable and
power cables will be routed
through different trays
wherever such discrepancy
is found.
T i i A l i
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Tripping Analysis
CAUSE OF TRIPPING
• U#1 : Stub joint leakage
of Regulating stage
Reheater coil # 1.
Root Cause: • The cause of failure is
uneven load on hangers.
ACTION PLAN
• Regular DPT is donein all stubs and if required stubs arereplaced.
T i i A l i
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Tripping Analysis
CAUSE OF TRIPPING
• U#4 : Water wall Tube
leakage
Root Cause:
• Attachment weldfailure.
ACTION PLAN
• Exhaustive DPT andchecking of attachment welds.
T i i A l i
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Tripping Analysis
CAUSE OF TRIPPING
• U#8 : Unit tripped on
“Low Forward power
protection”
Root Cause: • Wiring problem and
termination problem in
the load transducers.
ACTION PLAN
• Duringrecommissioning
joint calibration byEMD & C&I will bedone to ensurehealthiness of loadtransducers.
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Oct 2008
T i i A l i
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Tripping Analysis
CAUSE OF TRIPPING
• U#7 : Unit tripped on
“Furnace Pr. High”.
Root Cause:
• Sudden dislodging of accumulated ash into BA
hopper .
ACTION PLAN
When ever slaggingtendency is observed :
a) proper and timely de-
ashing will be ensuredby increasing thefrequency.
b) Frequency of wall
blowers operationshall be increased.
T i i A l i
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Tripping Analysis
CAUSE OF TRIPPING
• U#2 : Unit tripped on
a) “Excitation field
failure protection”
b) “Stator earth fault”
Root Cause:
• Voltage fluctuations
caused due to defectiveBus PT of R and Y
phases.
ACTION PLAN
• The bus line PTs shall be
checked individually and
shall be included in the
testing check list.• New bus line PTs
procurement action shall be
initiated.
T i i A l i
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Tripping Analysis
CAUSE OF
TRIPPING
• U#2 : Unit tripped
due to Gen bkr. Trip
while taking UAT inservice.
Root Cause: Exact
cause of trippig can
be established after online supply change
over, if the problem
persists.
ACTION PLAN
• a) Control wiring checking
shall be done to find out
cause of “Gen Internal fault”
protection operation duringopportunity.
• b) UAT change over
scheme to be checked during
opportunity.
• c) In SOE, the status of unit
and station breaker contacts
shall be incorporated.
T i i A l i
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Tripping Analysis
CAUSE OF TRIPPING
• U#2 : Unit was manually
tripped as light reflection
on GT R-phase bus duct
was suspected as hotspot.
ACTION PLAN
• At night, hot spots areto be confirmed bymaking thesurroundings dark.
T i i A l i
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Tripping Analysis
CAUSE OF TRIPPING
• U#5 : Radiant S/H
Tube leakage
Root Cause:
• Short term overheatingdue to blockage.
ACTION PLAN
• End caps to beprovided whilecutting the verticaltubes.
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Nov 2008
T i i A l i
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Tripping Analysis
CAUSE OF TRIPPING
• U#2 : Unit tripped on“All ID Fan trip”protection due totripping of LOPs.
Root Cause:
• The CA busequipments got trippeddue to intermittent
voltage drop as R-phase contact of 415VCA bus reserveincomer breaker was
damaged.
ACTION PLAN
• The ageing Russian make 415V LT breakers (reserve) needs
to be replaced, Proposal shall
be initiated by 31/12/2008. for
replacement of reserve
incomer breakers and
sectionalizing breakers in
phased manner.• Availability of supply to
standby lub oil pumps/
equipments from other source
shall always be ensured.
T i i A l i
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Tripping Analysis
CAUSE OF TRIPPING
• U#3 : Unit stopped due
to RH Reg stg T/L from
RHS center bends of
Coil # 134, 135, 137 &LHS center bends of
Coil # 137
Root Cause:
• The suspected cause of
failure is Flue Gas
erosion.
ACTION PLAN
• Inspection and thickness
survey of bends at all four
sides and middle top and
bottom.• b) Lifting of ~50 coils
every year & balance based
on inspection and thickness
survey.
T i i A l i
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Tripping Analysis
CAUSE OF TRIPPING
• U#4 : Unit tripped twice
on “Turbine trip
protection”.
Root Cause: TheOverheating of TTS
supply supervision relay
due to partial release of
one of the Turbine tripmanual push buttons in
the control desk
ACTION PLAN
• The Turbine trip manual
push button was checked
and released properly.
The operation of pushbuttons checked and
cleared.
• Turbine trip to Generator
trip timer was replaced.
Tripping Anal sis
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Tripping Analysis
CAUSE OF TRIPPING
• U#8 : Unit was manually
tripped as drain line
(MAL-12) before HPCV-
2 got sheared just abovethe erection weld joint.
ACTION PLAN
• Sample being sent toR&D for analysis.
Tripping Analysis
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Tripping Analysis
CAUSE OF TRIPPING
• U#8 : Water Wall Tube
leakage on (RHS) near
WWSB No.-75 Right
Tube no. 1 at anelevation of -18.5 mt.
Root Cause:
• The suspected cause of
leakage is Shop Joint
failure.
ACTION PLAN
Shop joint to beinspected andradiographed inphased manner.
Tripping Analysis
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Tripping Analysis
CAUSE OF TRIPPING
• U#10 : Water Wall Tube
leakage on (LHS) tube
no -1 towards right from
WWSB No.-18 at anelevation of 50mt.
Root Cause:
• The cause of leakage is
attachment weld failure.
( Membrane welded with
the failed tube was
having weld defect.)
ACTION PLAN
Refractory holdingplate weld will bechecked thoroughlyin the wall blowers
area and repair work will be taken up asper condition.
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Dec 2008
Action Plan to reduce Forced Outages
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Action Plan to reduce Forced Outages
CAUSE OF TRIPPING
• U # VIII (08/12/08):TL in Platen S/H panel# 13 and 14
• Root cause : Bulgingdue to suspected longterm overheating.
ACTION PLAN
• Regular S/H & R/H MetalTemp monitoring beingdone and reviewed inDPM.
• Metal temp to bemaintained withinprescribed limit bykeeping burner tilt down
and by giving adequate HPspray.
Action Plan to reduce Forced Outages
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Action Plan to reduce Forced Outages
CAUSE OF TRIPPING
• U # IX (09/12/08): TLin W/W “S” panel.
• Root cause : Ash ladenAir Erosion form thenarrow gap betweensealing strip and LeftWater Wall (This gapshave been sealed
during last OH,however, onetrapezoidal piece founddislocated.)
ACTION PLAN
• Sealing of gaps between“S” panel and verticalwater wall to be ensuredduring every OH.
• In U#10 the above gaps tobe sealed during overhaul.
Action Plan to reduce Forced Outages
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Action Plan to reduce Forced Outages
CAUSE OF TRIPPING
• U # VI (10/12/08):
Unit got tripped on
„Loss of excitation‟
• Root cause : Failureof DVR-UM Pulse
Final stage Power
supply module-1
ACTION PLAN
• Reason for failure of pulsefinal stage power supply
module is to be ascertained
to avoid recurrence of such
failures. Matter has been
taken up with OES M/S
BHEL
Action Plan to reduce Forced Outages
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Action Plan to reduce Forced Outages
CAUSE OF TRIPPING
• U # VII (12/12/08): TL
in water wall front side
tube no 11 from RHS
at 46.5mt.• Root cause : Long
Term Overheating due
to Partial chocking at
Ring Header Orifice(30% of the orifice
area was blocked with
corrosion material)
ACTION PLAN
• During OH ring headerorifice to be removed and
water wall flushing to be
ensured as per practice.
Action Plan to reduce Forced Outages
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Action Plan to reduce Forced Outages
CAUSE OF TRIPPING
• U # V (13/12/08): TL
in SCW near M/H # 14
• Root cause : Erection
joint failure.
ACTION PLAN
Action Plan to reduce Forced Outages
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Action Plan to reduce Forced Outages
CAUSE OF TRIPPING
• U # IV (17/12/08):Unit got tripped on“Generator field brkr.Main exc. trip”
• Root cause : Highervoltage drop whenstandby exciter wastaken into service. Alsovoltage could not be
built up in time
ACTION PLAN
• Revision of LMI regardingChange over of exciter inview of the R&M of unitswith DDCMIS. The LMIfor Exciter changeover
will be reviewed andrevised as per the Unitload conditions
• b) Reason for failure of
power supply card is to beascertained to avoidrecurrence of such failures,Matter has been taken upwith OES M/S BHEL
Action Plan to reduce Forced Outages
7/31/2019 Outages 2008-09
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Action Plan to reduce Forced Outages
CAUSE OF TRIPPING
• U # X (18/12/08): TL
in Spacer tube in
between Re-heater
panel # 1 & 2• Root cause : Spacer
tube in between Re-
heater panel # 1 & 2
pin-hole fracture inerection joint.
ACTION PLAN
Action Plan to reduce Forced Outages
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http://slidepdf.com/reader/full/outages-2008-09 78/79
Action Plan to reduce Forced Outages
CAUSE OF TRIPPING
• U # VIII (28/12/08):
Unit stopped due to
gasket leakage from
drum manhole (RHS).
ACTION PLAN
• Manhole cover bluematching to be ensured
during OH.
Action Plan to reduce Forced Outages
7/31/2019 Outages 2008-09
http://slidepdf.com/reader/full/outages-2008-09 79/79
Action Plan to reduce Forced Outages
CAUSE OF TRIPPING
• U # VII (30/12/08): TL
in water wall front side
near Soot blower no 5
at 43mt
• Root cause : Due soot
blower erosion
thickness got reduced
in T4 towards rightnear WWSB no 5. That
created fish mouth
i i h f il d
ACTION PLAN
• Following checks are to bedone during /after everywall blowing :
– Rotary motion of wall
blower to be ensured, – Poppet valve closing to
be ensured after blowing,
– If a Wall blower gets
stuck-up inside thefurnace, steam to beisolated immediately andmaintenance personnel to