transformer failure

10/30/06 E:/wkg_fdr/ppt/slide_prsnt1.ppt

Date of failure : 18.06.05 at 9:18 AM18.06.05 at 9:18 AM

Type of failure : NewType of failure : New

FAILURE ANALYSIS

C-43 Transformer’s 33 KV side cable failure

Back

Incidence Detail

A.K.Gupta

Current of C40 & C43 Trf were zero. Trf C 55 was on load & Bus coupler II at 33 KV was ON . At 13.6 KV bus Tx C 40 , Bus tie-1 and TG5 breakers were off but C 43 and Reactor-1 breakers were ON. C 43 & C 40 Breakers at 33 KV side were also OFF. C 43 ABCB Breakers were drawn out. After IEM clearance TG 5 synchronised at 01.35 pm & Boiler 5 & 6 connected thereby.

36

At 9.18 am Voltage dip

was observed, TG5 tripped off

& at ECR sound of

tripping 3 nos 13.6 KV ABCB

breaker was heard.

Simultaneously Boiler 5 &

Boiler 6 tripped off, Boiler 7 F.D Fan A tripped off.

Current of C40 & C43 Trf were

zero.

At 9.18 am

Voltage dip was

observed, TG5

tripped off & at ECR sound of tripping 3 nos 13.6 KV

ABCB

breaker

was heard

.

53Turbo

Generator #5

TG Buildin

g 4 Hrs 17

mins

13.35 PM

09.18 AM

18/06/05

PH3/05/019OPNPH#3

DEPARTMENT INVESTIGATION AND ACTION

TAKEN

FAILURE CODE

FAILURE DESCRIPTION

.F.I.R

EQUIP.

CODE

EQUIP. DESCRIPTI

ON

EQPT. LOCATION

DELAY BOOKE

D

EVENT DURATI

ON

END TIME

START

TIME

DATE OF

EVENT

ARCHIVE NO.

SECDEPT

Back

Incident DetailIncident Detail


Problem Statement :

C-43 Transformer cable failed during operation of this transformer causing tripping of TG # 5 , C-40 & C-43 transformer.Approx. 7MW power was being evacuated through both transformers it at the time of tripping.

Back


Burnt portion C-43 transition joint C-43 Transformer whose cable failed

Back

33 KV & 13.6 KV Power System SLD (PH#3)

NGR(5 Ω)

TG-5

2500 AVCB

Adopter

TG-4

2500 AVCB

13.2 KV

Bus Tie-I

2500 A

Reactor# 0130 MVA

(1260 Amps)

Bus Tie-II

Bus Tie-III

Bus Tie-IV

Bus Tie-V

Empty Cubicle

13.2 KV

Reactor# 0230 MVA

1260) Amps)

Empty Cubicle

13.2 KV

Reactor# 0330 MVA

(1260Amps)

Spare 13.2 KV

Reactor# 0430 MVA

(1260 Amps)

ABCB2500 A

(1000 MVA)2500

BC-I BC-II

CPFeeder - I

1250 A

ESSFeeder - I

1250 A

ESS Feeder - II

NA

CPFeeder - II

MPDSFeeder

TOP

(NOT INSERVICE)

Bus PT-IC-4020 MVA

13.6 KV / 33 KV

C-4320 MVA

13.6 KV / 33 KV

Bus PT-II

Live PT Live PT

Bus PT - III

C-5520 MVA

13.6 KV / 33 KV

1250 A 1250 A 1250 A

2500 2500 2500 2500

Adopter Adopter

Back

FunctionThis cable is connected between 33KV side of the C-43 transformer and 33KV evacuation bus having SF6 breakers of VOLTAS make. In normal condition each 20MVA evacuates 6 -7 MW of power.

The cable has following Specifications:

•Voltage grade – 33KV•Cable size – 3c x 300 sq.mm 19/33 KV PILCA & XLPE•Make – Fort Gloster – PILCA – 1990, XLPE – 1997•Date of installation of PILCA cable – 1991•Date of installation of transition joint which failed – 1998

Back

Observations

Not okContinuity not available –open ckt fault in B-phase.

Cable to be closed ckt & Multimeter should show continuity

Cable –open circuit(C-43)

Transition joint failure confirmed

Testing shows failure at 3.5% dist.

Transition joint distance-5% fr Tx.

Transition joint may have failed

OkE/F & Buchholz relays operated

E/F or Buchholz or O/C should operate

Operation of relays

OKPh to Gr > 100M-ohm

Should be > 33M-Ohm

Low IR value of Tx (C-43)

OKPh to Ph >100M-ohmPh to Gr > 100M-ohm

Should be >33 M-ohm

Low IR value of cable only (C-43)

OKPh to Gr > 100M-ohm

Should be >33 M-ohm

Low IR value of cable + Tx (C-43)

Remarks/Action taken

observationNormal conditionProbable causes

Back

Observations (after exposing the failed joint):-1. By exposing the cable route it was found that transition joint between 3c x 300

sq.mm PILCA, aluminium cable & 3c x 300 sq.mm XLPE aluminium cable has failed.

2. At PILCA side of transition joint one core found sheared and about 5” of core material found completely burnt and missing.

5. From end of combined tubing set, up to a distance of about 5”, core material of one core found missing due to burning away of aluminum conductor

8. Outer shell, tinned copper wire mesh and earthing braid of that portion found burnt.

10. In the other two cores, outer layer of paper of core found partially burnt at a distance of 50 mm away from stress control tube.

13. Perforated paper metallic screen of all cores found burnt at that portion.

Back

Burnt & missing core of joint –PILCA side

Back

Root Cause Identified

Insulation failure occurred in cable joint due to oil barrier tube not shrunk properly during installation and voids were left at that portion - Human error

Back

Remedial Action taken

Rejointing of failed cable’s transition joint got done by Reychem expert in presence of TISCO expert agency (i.e. Service & Transmission) as per guidelines given by Reychem.

Back

Preventive Actions taken The Inspection pit for inspecting health of cable joints through

ULTRA PROBE has being made. This will give prior information for cable

joint failure. It will be checked at two months intervals.

Horizontal Deployment

1. It has been decided that all such HT cable joints of 33kv and above shall be put into inspection pit for periodic monitoring.

3. Healths of these cable shall be monitored at regular intervals through ULTRA PROBE.

Back

THANKING YOU


Date of failure : 01.06.05 ( 3.30PM to 5.15PM).06.05 ( 3.30PM to 5.15PM)

Type of failure : NewType of failure : New

FAILURE ANALYSIS – 4

Failure of Dynodrive – A in Boiler-6

Back

Incidence Detail

On investigation it was found that dynodrive bearing has

got ceased

Operation Foreman reported that Boiler 6 Stoker A has tripped

Boiler 6 Stoker A motor tripped

off

Boiler 6 Stoker A Dynodrive

unit

Boiler 6 Stoker A

1 hr 45 min

17.15 hrs

15.30 hrs

01/06/2005

PH3/05/017IEMPH#3

DEPARTMENT INVESTIGATION AND

ACTION TAKEN

FAILURE DESCRIPTION.F.I.REQUIP.

DESCRIPTION

EQPT. LOCATIO

N

EVENT DURAT

ION

END TIME

START TIME

DATE OF

EVENT

ARCHIVE NO.

SECDEPT

Back


Problem Statement

Boiler # 6 stoker A tripped as reported by the operator.

Back

Function (contd)Control Circuit Diagram of Dynodrive for speed control:

Back

Observations

Not OKBearing clearance

Not OKFound dustyShould be free from dust

Bearing

Not OK.Not rotating freely- bearing found defective

Should rotate freely

Dyno drive unit jam

OKRotated freely by handShould rotate freely by hand

Stoker Gear jam

OKMotor rotated by hand & found free

Motor shaft should rotate freely

Motor bearing jam

OKProperly insulatedGood insulation of motor

Motor burnt

Remarks/Action taken

Observation Normal conditionProbable causes

Back

Analysis

From the observations Dynodrive unit was found jammed, bearing dusty and After cleaning the bearing clearance was found on higher side.

Root cause

Bearing got jammed due to dust ingression, which led to the failure.

Back

Remedial Actions Taken

Replaced the defective Dyno drive unit with another and the system was started.

Preventive Actions

Air blowing of dynodrive unit once in a shift with the help of instrument air (existing practice is once in a day).

Sealing of – tacho cable entry hole, exciter cable entry hole to prevent ingress of dust into bearing of dyno drive.

Back

Horizontal Deployment

1. It has been decided by the TOP management that all such HT cable joints 33kv and above shall be put into inspection pit for periodic monitoring.

3. Healths of these cable shall be monitored at regular intervals through ULTRA PROBE.

Back

PRESENT MAINTENANCE SYSTEM

• For ‘A’ Category (critical) equipment condition based monitoring is being carried out.

• For ‘B’ Category equipment maintenance practice ‘Inspection & Repairing’ is being carried out.

• For ‘C’ Category equipment maintenance is being done as and when required.

Back

SCHEDULE / TIME BASED MAINTENANCE

Sl. No. Equipment Purpose Schedule

Cleaning Once in 3 Months

Elastic Pad Checking Once in 6 Months

Valve check Bi-Monthly

Ring change Once in 4 Months

Foundation Bolt / V. Belt Inspection Once in 4 Months

3 C.W.Pump Coupling Bush and foundation bolt Check Once in 6 Months

Coupling Greasing Once in 3 Months

Oil tank & oil cooler cleaning Yearly

Bearing greasing Once in 3 Months

Bearing inspection Yearly5 Fans

1 Oil Centrifuge

B.F.Pump4

2 Reciprocating Compressor

Back

CONDITION BASED MAINTENANCE

Now our focus is to shift from Time based maintenance to

condition based maintenance (CBM) to reduce maintenance

cost, increase equipment reliability and increase mean time to

repair.

Back

CONDITION MONITORING – PRESENT STATUS

On-lineOil temperature

Maint. Engg.MonthlyVibrationC.E.Pumps

On-lineExhaust pressure

Maint. Engg.MonthlyOil view analysis

Maint. Engg.Once in three monthsOil particle count

Maint. Engg.MonthlyOil Ferrography

On-lineAxial shift (MOP)

On-lineAxial shift (Turbine)

On-lineBearing metal temperature

On-lineFirst stage pressure

Maint. Engg.MonthlyBearing housing vibration

On-lineShaft vibration

Turbo Generator

Agency FrequencyParameterEquipment

Back

CONDITION MONITORING

We have procured a handy Vibration Pen and Vibration Measurement on regular interval is being carried out by our Shift Personnel for following equipment.

• Circulating Water Pumps - 6 Nos.

• Boiler Feed Pumps - 5 Nos.

• Instrument Air Compressors - 3 Nos.

• Induced Draft Fan for Boiler - 8 Nos.

Based on the report necessary corrective action is being done in house like dynamic balancing, bearing changing etc.

Back

LUBRICANTS IN USE

Boiler & Fan and Ash Plant bearingGrease6.

Screw Service Air CompressorUltra-10W5.

C.T.Fan GearboxSS-1504.Reciprocating Compressor, Stoker Primary GearboxSS-2203.

Stoker Gearbox secondary, Ash Plant GearboxSS-320 2.

Turbine, Boiler Feed PumpSP-681.

EquipmentLubricantSl. No.

Back

LUBRICATION MANAGEMENT

•Arresting leakages & sources of contamination

•Storage & disposal of Lubricant

•Standardization of Lubricant

Back

EARLIER

• SP 68

• SS150

• SS 220

• SS 320

• Ultra 10 W

• Grease (Lithium complex)

STANDARDIZATION OF LUBRICANT

WE ARE EXPLORING THE POSSIBILITY OF

STANDARDISATION

Back

PRESENT

• SP 68

• SS150

• SS 220

• SS 320

• Ultra 10 W

• Grease (Lithium complex)

TYPE OF LUBRICANT & APPLICATION

LUBRICANT- CIRCULATING TYPE

•LUBRICATION OIL FOR TURBINE BEARING

• CHECKING OF OIL PROPERTIES PERDIODICALLY

• PREVENT SOURCES OF CONTAMINATION

• CONSUMPTION TREND

• PREVENT SOURCES OF LEAKAGES

• LUBRICATION OIL FOR COMPRESSOR’S BEARING / BUSH

• LUBRICATION OIL FOR BEARINGS OF ALL BOILER FEED PUMPS

POINTS OF MONITORING ACTION TAKEN


Back


LUBRICANT- TOTAL LOSS TYPE

• GREASE FOR STOKERS BEARING GREASING

• GREASE FOR ALL PUMPS & MOTORS BEARING GREASING

• FREQUENCY OF APPLYING GREASE

• DEFINED THE FREQUENCY AND RIGHT QUANTITY OF GREASE

• CONDITION OF THE GREASED SURFACE

• PREVENT SOURCES OF CONTAMINATION

• GREASING FOR ROPES AT WAGON TRIPPLER

POINTS OF MONITORING ACTION TAKEN


Back

STORAGE & DISPOSAL OF LUBRICANT

We draw the material from central stores. Lubricants drums are kept in designated places.

PROCUREMENT AND STORAGE

VISUAL CONTROL OF STORAGE

At lubricant storage place, for each type of lubricant name / grade is marked

DISPOSAL OF USED LUBRICANT

Disposal of used lubricant is being done as per environmental norms.

Back

AVERAGE MONTHLY LUB. CONSUMPTION

1942

1522

1104

1087

940

900

830

0

500

1000

1500

2000

2500

Bas

e Le

vel

Avg

.`04

Avg

.`05

Q1-

FY06

Jul`0

5

Aug

`05

Targ

et -

FY06

Con

sum

ptio

n in

Litr

es /

Mon

th

GOOD

Back

PERIOD

STEPS TAKEN FOR REDUCING LUB. CONSUMPTION

• Off-line Oil Filtration system provided for Turbo Generators

• Regular Centrifuging of Turbo equipment oil.

• Dehydrator put on service in TG-4 & 5.

• Most of the leakages in both TGs were attended during the combined shutdown.

• Proper training on handling and application of Lubricants.

• Mechanised handling system provided.

• Proper storage and maintenance of oil storage area to prevent any mix up and wastage.

• Condition based monitoring and oil changing based on condition.

Back

RESULT

1. Interruption rate

2. MTBF

3. Lubrication cost

4. Maintenance cost

Back

10

6

3

00

2

4

6

8

10

12

Base Level FY 05 FY 06 Target

No.

of I

nter

rupt

ion

No. Of Interuption (T.G)

INTERRUPTION OF TURBO GENERATORS

Goo

d

Back

0

PERIOD

TG#4 INTERRUPTION

10

6

3

00

2

4

6

8

10

12


No. o

f Int

erru

ptio

n

No. Of Interuption (T.G) Back

TG#5 INTERRUPTION

10

6

3

00

2

4

6

8

10

12


No.

of I

nter

rupt

ion

No. Of Interuption (T.G) Back

15

11

3

00

2

4

6

8

10

12

14

16


No.

of I

nter

rupt

ion

No. Of Interuption (Blr.)

INTERRUPTION – BOILER

Goo

d

Back

0

PERIOD

BOILER INTERRUPTION

15

11

3

00

2

4

6

8

10

12

14

16


No. o

f Int

erru

ptio

n

No. Of Interuption (Blr.) Back

MEAN TIME BETWEEN FAILURE OF TG#4 & 5

4.0 Month

3.0 Month

M.T.B.F.FY`05

2.0 Month2.0 MonthTG#52.

4.0 Month3.0 MonthTG#41.

M.T.B.F.FY`06

M.T.B.F.FY`04

EquipmentSl. No.

3

2

3

44

2

00.5

11.5

22.5

33.5

44.5

TG#4 TG#5

M.T

.B.F

. (In

Mon

th)

FY`04 FY`05 FY`06

Back

MEAN TIME BETWEEN FAILURE OF BOILERS

12.0 Month 2.0 MonthBoiler – 84.


No Failure 6.0 MonthBoiler – 62.


M.T.B.F. FY`06

M.T.B.F. FY`05

EquipmentSl. No.

12

6 6

2

12 12

6

12

0

2

4

6

8

10

12

14

Boiler#5 Boiler#6 Boiler#7 Boiler#8

M.T

.B.F

. (In

Mon

th)

FY`05 FY`06

Back

No Failure

LUBRICATION COST

Back

7.31

3.30

6.58

0

1

2

3

4

5

6

7

8

Total FY`05 Total FY`06(Till Aug'05) Target FY`06

Rs.

Lak

h

Total FY`05 Total FY`06(Till Aug'05) Target FY`06Target is 10% less than FY`05

Goo

d

PERIOD

CONSUMPTION & COST LUBRICANT WISE

Back

7.31

3.30

6.58

0

1

2

3

4

5

6

7

8


Rs

. L

ak

h


Object 12

MAINT. COST EXPENDITURE

15.63

23.78 25.28 26.65

21.56

05

101520253035404550

Apr`05 May 05 Jun`05 Jul`05 Aug`05 Sep`05 Oct`05 Nov`05 Dec`05 Jan`06 Feb`06 Mar`06 Avg.YTD

Rs.

in L

akhs

PERIOD

GOOD

Monthly Target-23.75 L (FY`05-06)

2005 – 2006

Back

MAINT. COST EXPENDITURE

45.3

26.8

19.93

26.7

21.16

29.09 29.2

14.0317.43

11.83 13.29

23.15

35.31

22.33

05

1015

202530

3540

4550

Mar`04 Apr`04 May`04 Jun`04 Jul`04 Aug`04 Sep`04 Oct`04 Nov`04 Dec`04 Jan`05 Feb`05 Mar`05 Avg.YTD

Rs.

in L

akhs

GOOD

Monthly Target-23.75 L (FY`04-05)

No shutdown / washout

during this period. So

cost was low.

1. Washout of Blr.-8.2. Year pending bill (service) clear for about 18.0 Lakh

2004 – 2005

BackPERIOD

FUTURE ACTION PLAN

Analysis to be startedMTTR

Continuous Process.Skill gap matrix prepared and training programme prepared.

Enhancing skill for maintenance staff

To be introduced for Auxiliary equipment such as I.D.Fans, C.W.Pumps, C.E.Pumps, and Compressors,

Already provided for TGs and partially extended to other equipment.

Condition based Maintenance system

Dec`05Analysis to be started Spare / Inventory Management

To minimise Red Tag by supporting to JH ContinueRed Tag Management

Zero Per month by Dec`06ContinueFailure Analysis

TargetStatusActivities

Back

SPARE MANAGEMENT

1. IDENTIFICATION OF CRITICAL SPARES

2. PROCUREMENT

3. STORING

4. INVENTORY

Back

LIST OF CRITICAL SPARES

Back

45.3

26.8

19.93

26.7

21.16

29.09 29.2

14.0317.43

11.83 13.29

23.15

35.31

22.33

05

1015

202530

3540

4550

Mar`04 Apr`04 May`04 Jun`04 Jul`04 Aug`04 Sep`04 Oct`04 Nov`04 Dec`04 Jan`05 Feb`05 Mar`05 Avg.YTD

Rs. in La

khs

Object 16

PROCUREMENT AND STORING

Back

*Indenting (SAP)

PROCUREMENT THROUGH PM MODULE (SAP)

Order placement (SAP)

Material received at Central Store

Material drawn to Sectional Store

*Indenting (SAP)

PROCUREMENT THROUGH OFFLINE

Order placement(SAP)

Material received at Central Store

Material reservation raising (SAP)

Material drawn to Sectional Store

*Indenting based on verbal feedback and planned shutdown

**Inventory can be seen in SAP for individual item

INVENTORY STATUS

Back

90.28

70

85.4877.6

74.1178.15

70

0

10

20

30

40

50

60

70

80

90

100

Avg.FY`05

TargetFY`05

Apr`05 May`05 Jun`05 Jul 05 Aug`05 Avg.TargetFY`06

Rs.

Lak

h

Avg. FY`05 Target FY`05 Apr`05 May`05 Jun`05 Jul`05 Aug`05 Avg. Target FY`06

PERIOD

MTTR

Back

Review of activities & resources, exploring new ideas / methods

1821Boiler Overhauling

Review of activities & resources710Wet washing

-do-710Condenser cleaning

-do-Transformer overhauling

Action to be takenPlanned (days)

Present (days)Activity

BOILER OVERHAULINGPH3/MEC/05.00 ANNEXURE – 4

EFFECTIVE DATE: 15.12.2001Page 1 of 3

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 211

2b 2c 2d2h

3c4d

8f

8h

9a 9c

10c

11b12

10a 10b10d

11a

9b 9d9e9f

8d 8e8g

8i 8j

6d7

8a 8b 8c

56a 6b 6c

4c4e

4f

2i3a 3b

4a 4b

(PH 3)

2a2e 2f 2g

Back

BOILER OVERHAULING – ACTIVITIES PH3/MEC/05.00 ANNEXURE – 4

EFFECTIVE DATE: 15.12.2001Page 1 of 3

Object 19

Object 20

Object 21

Back

PQCDSM

1.20.600.65NO. OF ACCEPTED SUGGESTION/EMP/YR.SUGGESTIONM

04.0-MINOR

00.00MAJORNO. OF ACCIDENTS

06.012NO. OF UNPLANNED OUTAGE OF TG./YRCOMPLIANCE ON ABP MOU COMP.D

206204.8210Kg/Ton of steamCOAL RATE

12931337Rs/MWhPOWER COSTC

4039.336.4MVARREACTIVE GENERATIONQ

225.6287.7281.494KW/EMP. PRODUCTIVITY

0218NOS./MONTHTOTAL NO. OF FAILURE

4454.367.841MWGENERATION

0166.0347HRSINTERUPTION HRS

03.021NO.NO. OF INTERUPTION

10097.183.87%PERFORMANCE RATE

96100.092.79%T.G AVAILABILITY

9398.9590.5%BOILER AVAILABILITY

89.399.0170.7%OEE

P

Target FY '06Actual till dateBase LevelUNITPerformance IndicatorCriteria

LUBRICATION CONSUMPTION

Back

16422

6910

12316.5

0

2000

4000

6000

8000

10000

12000

14000

16000

18000


Litr

e / K

g


Target is 10% less than FY`05

• Support to Jishu Hozen -

Continue

• Critical ranking of Equipment -

Completed

• Preparation / Modification of Maint. Schedule -

Completed

• Lubrication Management -

Continue

• Condition Based Monitoring - Started

Imparting on the job training to Jishu Hozen Members for cleaning, lubrication, inspection & tightening.

Lack of skill in Jishu Hozen Members for Fuguai identification & rectification.

Condition based maintenance Corrective maintenance

Conventional maintenance style.

Minimize failure to ZEROHigh failures rate

OBJECTIVESBACKGROUND

BACKGROUND & OBJECTIVE

BOILER AVAILABILITY

GO

OD

90.5

93.7

89.9 10

0

92.5 93

8.6 6.5

7.0

0

20

40

60

80

100

120

Benchmark (06/03 to05/04)

Avg. FY`05 (Jun`04-Mar`05)

Qtr.1 Jul 05 Avg. Till Date Target FY`06

90.5 93.7

98.5 98.95 100

Blr-5 & 8 w/o

BOILER WASHOUT

Percentage

100

Period

OEE

GO

OD

70.4

92

87.9

8

97.8

9

90.4

5

89

8.6 8.6

7.04

0

20

40

60

80

100

120

Benchmark (06/03 to05/04)

Avg. FY`05 (Jun`04-Mar`05)

Qtr.1 Jul 05 Avg. Till Date Target FY`06

70.4

92.096.1 97.89 99.01 100

Blr-5 & 8 w/o

OUTAGE DUE TO WASHOUT

Percentage - 104 days Boiler Washout- 27 days planned shutdown of TG

TG SHUTDOWN

Period

RESULT

As a result of the above steps oil consumption in the

Turbo Generators was come down to about 20 to 25%.

Mainly due to reduction in online filter jamming and

cleaning. Each time when we clean this filter about 25

litres of oil is getting drained out. It is totally a loss.

Back

Aux. Power Consumption

7.90

6.43 6.35 6.837.88 7.36

0

2

4

6

8

10

BENCHMARK FY`03 FY`04 FY`05 Q!FY06 Jul -05 FY`06 Ti l l date Tar get

GOOD

Period

Aux. Power (%)

Power Cost

1293

1435

1337

1000

1100

1200

1300

1400

1500

1600

1700

03-04 04-05 Till Date Target

Rs. / MWh

Good

Period

Benchmark

• Completion of JH Step # 4

• Completion of first cycle of training as per skill

gap

matrix.

• Reduction in Oil consumption.

• Sustain the higher operational performance.

• To Focus on MTTR

TPM – Present Focus

transformer failure

Documents

kv bus tx c

transition joint c

cable failedback33 kv

transformer cable

kv evacuation bus

kv abcb breaker

pilca cable

pptburnt portion c