Response Planning and Machine Implementation of Emergency - - PDF document

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April 2005

Implementation of Emergency Response Planning and Machine Diagnostics.

Ken Bailey

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Background to Emergency Response Planning Unit Disaster Recovery and the Concept of Emergency Response Planning

Agenda

Practical implementation of Emergency Response Planning Use of generator diagnostics to identify and monitor risks

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Background to Emergency Response Planning Unit Disaster Recovery and the Concept of Emergency Response Planning

Agenda

Practical implementation of Emergency Response Planning Use of generator diagnostics to identify and monitor risks

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500 1,000 1,500 2,000 2,500 3,000 3,500 4,000 4,500 5,000 5,500 6,000 2 4 6 8 10 13 16 18 20 22 24 26 28 30 32 34 36 40 42 46 49 54

Years Old (as at Aug 2001) Installed Capacity (MW) NUCLEAR STEAM COMB CYC COG GAS TURB (combustion) GAS TURB (OCGT)

UK thermal capacity by age

(by Prime Mover Group)

69% of Steam and 23% of Nuclear Capacity in the UK is 30 years

• r older

91% of Steam and 42% of Nuclear Capacity in the UK is 20 years or older 99% of Steam and 90% of Nuclear Capacity in the UK is 10 years or older

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Generator ages graph

Air Cooled <60MW 1794 Units Air Cooled >60MW 1145 Units H2/H20 <500MW 845 Units H2/H20 >500MW 309 Units

AIR <60MW 100 200 300 400 500 600 700 800 900 1000 Mannheim Baden Belfort Stafford Vasteras Wroclaw Essen Charleroi Sesto

Volume (Units)

>20 year 10-20 year <10 year

H2/H2O <500MW

50 100 150 200 250 300 350 400 Mannheim Baden Belfort Stafford Vasteras Wroclaw Essen Charleroi Sesto

Volume (Units)

>20 year 10-20 year <10 year

H2/H2O >500MW

20 40 60 80 100 120 140 160 180 200 Mannheim Baden Belfort Stafford Vasteras Wroclaw Essen Charleroi Sesto

Volume (Units)

>20 year 10-20 year <10 year

AIR <60MW

100 200 300 400 500 600 700 800 900 1000 Mannheim Baden Belfort Stafford Vasteras Wroclaw Essen Charleroi Sesto

Volume (Units)

>20 year 10-20 year <10 year

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General cost distribution for Power Industry

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The Industry Trend

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Ageing plant & deregulation - The effects

Aging factor 55% of coal-fired thermal plant has approached or passed

theoretical design life.

Cost cutting factor. Deregulation, price regulation, demand changes, bottom line

profit, has squeezed power plant owners to fixed overheads and maintenance budget cuts.

Change in plant operating demands Plant flexibility - particularly responsiveness, start-up / shutdown

rates and loading curves pushed to design limits and beyond.

Loss in expertise Engineering gap, reduction of essential staff.

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Operational effect

What does this mean? Running older machines with higher demands and more

constraints.

Demands: Reliability, Availability, Higher performance,

Efficiency improvement, more flexible running regimes all to increase profit margins.

Constraints: Lower maintenance budgets, Minimum spare

holdings, shortages of experienced staff, Shorter outages with longer time between outages.

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Operational effect

To survive in a competitive market the power operator needs to

be able to adapt to the constant demands and changes in the market place.

This means taking higher risks more often. But the key word is risk. Risk can be minimized or reduced but

not eliminated. Failures will occur.

Targeted 90 / 7 / 3 concept.

– i.e world class stations still have unplanned outages.

To minimize the effect of failure and down time you need to be

proactive to handle the situation. THIS LEADS TO ERP (EMERGENCY RESPONSE PLANNING) How does this affect the Power industry Operator?

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Background to Emergency Response Planning Unit Disaster Recovery and the Concept of Emergency Response Planning

Agenda

Practical implementation of Emergency Response Planning Use of generator diagnostics to identify and monitor risks

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What is Unit Disaster Recovery ?

Loss mitigation of an unplanned outage

following a minor/major component failure.

– Requiring/causing an unplanned outage, – Potential for significant time duration for repair, with spares supply. – Resulting in high unavailability and substantial loss of revenues.

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Typical Categorisation of Events

Catastrophic Event

– Usually results in the requirement to rebuild, or replace the machine. – Eg Cracked generator rotor shaft.

Major Event

– Requires the unit to be dismantled resulting in substantial repair time and loss of revenue. – Eg Stator earth fault, rotor earth fault.

Minor Event

– Can be repaired in a short duration but requires the unit to be brought off- line. – Hydrogen leak, gas-into-water leak.

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Outline of an Emergency Response Plan

Due to aging,demands and constrains.

– It is highly likely that some machines will fail during their remaining life.

ERP in its simplest form is a “what if” scenario that considers

failure conditions tailored to individual machines & their condition

– Team approach to developing effective and detailed plans covering a variety of scenarios.

Generator stator, rotor & exciter failure scenarios proposed

based on ALSTOM’s fleet experience

– Each failure condition pre-planned and risk assessment performed. – Programmes agreed jointly between OEM and customer. – OEM & Customer resources identified.

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Emergency Response Plan

– The “what if” programme, tailored to individual machine ranges and generic maintenance issues generates all repair requirements.

• Specialist equipment and tooling identified

– QA planning, process specifications and risk assessments are produced

• Identified from the detailed planning process.

– Contract and consumable spares for failures with high risk are held on site.

• List of local suppliers identified & maintained

– Drawing packs are identified and available within the local centre for every volume of the ERP.

• With each set of drawings a full set of parts lists.

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Stages of Emergency Response Planning

Consultation phase

– To execute an ERP properly, it is essential to understand the operating regime, and condition of the existing plant.

Risk assessment of plant

– Identifies through analysis of operating history, the major risk areas of the machine.

Failure scenario identification

– From the risk assessment the key failure scenarios can be tailored to suit individual machines

Assessment of operator’s spares holdings

– Identifies which spares are held in order to support the execution of the ERP process.

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Structure of ERP Documentation Part 1

Consists of tailored flow charts, decision

points, communication channels & commercial arrangements

– Simple but effective procedure to allow rapid identification of fault type, who to contact, & support arrangements in place.

Typical ERP contains seven sections

– Section 1. Master Process Flow Diagram – Section 2. First Actions in Customer – Section 3. First Actions in ALSTOM – Section 4. ERP Project Organisation – Section 5. Communication Channels – Section 6. Commercial Arrangements – Section 7. Further Issues

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Structure of ERP Documentation Part 2

Consists of several volumes

representing individual failure scenarios.

Typical volume is split into ten sections

– Section 1. Failure Identification – Section 2. Failure Recovery Location – Section 3. Failure Recovery Process – Section 4. Recovery Programme – Section 5. Documentation – Section 6. Parts List – Section 7. Consumables – Section 8. Tooling – Section 9. Resource Schedule – Section 10. Recommendations

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Part 2 Stator Failure Modes

1.1.01 Earth Fault Bottom Coil Slot Section 1.1.02 Earth Fault Bottom Coil Overhang Section 1.1.03 Earth Fault Top Coil Slot Section 1.1.04 Earth Fault Top Coil Overhang Section 1.1.05 Flash Over Between Phases 1.1.06 Core Damage Object Going Through Air Gap 1.1.07 Severe Fretting of Overhang Insulation 1.1.08 Gas \ Water Leak through Water Box Joint 1.1.09 Gas \ Water Leak through "Worm Hole“ 1.1.10 Gas \ Water Leak through PTFE Fitting 1.1.11 Gas \ Water Leak through Ring or Ferrule 1.1.12 Coil Damage through Blocked Tubes 1.1.13 Phase Ring Insulation Failure 1.1.14 Phase Connection to Terminal Failure 1.1.15 Manifold Support or Bellows Failure 1.1.16 Cooler Leaks 1.1.17 H2 Seal Failure 1.1.18 Damaged Windings during Removal/Assembly 1.1.19 Line and Neutral Bushings Failure 1.1.20 Large Number Wedges Loose

Structure of ERP Documentation Part 2

Typical Generator Stator Failure Scenarios

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ERP Documentation Part 2

Part 2 Rotor Failure Modes

1.2.01 Earth Fault in the Rotor Slot 1.2.02 Earth Fault to the Retaining Rings 1.2.03 Inter Turn Fault in the Slot Section 1.2.04 Inter Turn Fault in the Overhang Section 1.2.05 Damaged Cross Overs & Pole to Pole Conn 1.2.06 Cracked Retaining Rings 1.2.07 Stalk, FL Wedge or Flex Conn Failure 1.2.08 Damaged Shaft Comp, Fan Blade Failure 1.2.09 Damper Wedges Damage

Exciter Failure Modes

1.3.01 Rotor Winding Earth Fault 1.3.02 Rotor Winding Connection Failures 1.3.03 Diode Failures 1.3.04 Stalk Connection Failures 1.3.05 Main Stator Pole Winding Earth Fault 1.3.06 Main Stator Pole Inter Turn Failures 1.3.07 PMG Stator/Rotor Damage Failure 1.3.08 Air Cooler Damage

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PRINCIPLE OF A UNIT WITHOUT ERP TIME Major forced

• utage

Normal operation

Decision time Actual repair time Time saved by ERP

• When a forced outage occur significant time is taken on decision making as to:
• Identification of fault, resources, communication line, spares availability, tools and

equipment needed, financial / commercial implications, compilation of work scope and programs etc.

• All of the above have a direct input on the duration of the project. During a forced
• utage decisions have to be taken quickly and under high pressure conditions, this

highly increases the possibility of affecting or increasing the duration of the repair time.

• This also increase the possibility of mistakes, poor quality and rework during the project.
• All of this will lead to a delay in time to return of the unit, increasing down time profit loss

and overall execution cost.

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PRINCIPLE OF A UNIT WITH ERP TIME ERP reduces down time to a minimum Major forced

• utage

Normal operation

Decision time Actual repair time Time saved by ERP

When a forced outage occur on a unit with ERP in place the following benefits apply

• Each failure condition pre-planned
• Programmes agreed jointly
• ALSTOM & Customer resources identified
• All QA documentation, drawings & procedures in place
• All contract parts identified
• All consumables identified
• All specialist equipment available

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PRINCIPLE OF A UNIT WITH ERP

• Analyses major machine failure scenarios
• Plans repair process - in detail
• Identifies resources and materials required
• Helps estimate cost of repair
• Primarily aimed at reducing unplanned outage times
• Used to aid decisions on strategic spares holdings

All of this lead to reducing down time, profit loss and overall cost saving. The principal and information is not only applicable for a force outage, but can also be used for the planning and execution of work during a planned outages.

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• In a major forced outage incident ERP is the key to minimizing lost production
• All failure scenarios are pre-planned with the resources, contract materials and consumable

identified and available either on site or from specialist suppliers.

• Top project management and key decision makers are on site throughout.

Summarise Emergency Response Planning

Generator failure stops production - causing high unplanned costs to customers Emergency Response Planning

TIME ERP reduces down time to a minimum PRINCIPLE OF ERP Major forced

• utage

Normal operation

Decision time Actual repair time Time saved by ERP

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Background to Emergency Response Planning Unit Disaster Recovery and the Concept of Emergency Response Planning

Agenda

Practical implementation of Emergency Response Planning Use of generator diagnostics to identify and monitor risks

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Case study Emergency Response Planning

Type of Power Plant:

– Nuclear PWR 2500MVA (2x1252MVA) plant, first unit commissioned 1984 – Life: 20yrs, 140,000 operating hours – Located: USA

Issues:

– Shortage of replacement power. – No effective spares cover. – Rotor operating at the limit of acceptable machine vibrations

Owner drivers:

– Security of supply – Availability – Long-term market presence, and community perception – Assured quality of repairs

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Identification of Problem

Step change in shaft vibrations

• bserved during April 2003,

and again during October 2003.

– Leading to a vibration level approaching 11.0 mm/s 0-pk. – Compares to an ISO 10816- 2:1996 specification for 60Hz machines, class C/D limit for

• peration of 12.0 mm/s 0-pk.

– Machine was in an unacceptable condition for medium/long term operation.

Step Change in Vibration

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SONGS U3 GENERATOR - RFM Fault Location

Air gap search coil analysis had been conducted previously, including load

swing and machine de-load in February 2004.

To establish the current fault status a comprehensive set of measurements

were conducted using the ALSTOM Rotor Flux Monitor (RFM) on unit de-load prior to the outage.

8 Faults were identified affecting five coils across all four poles. Identification of the fault locations at speed was essential as not all faults may

have been present at rest with centrifugal forces no longer present.

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SONGS U3 GENERATOR RFM Measurements On De-Load

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SONGS U3 GENERATOR RFM Measurements On De-Load

3 Faults Clear Fault Identification

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SONGS U3 GENERATOR RFM Measurements On De-Load

Clear Fault Identification 1 Fault

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SONGS U3 GENERATOR RFM Measurements On De-Load

2 Faults Clear Fault Identification

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SONGS U3 GENERATOR RFM Measurements On De-Load

Pole 1

0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 1 2 3 4 5 6 7 8 9 10 11 Reading decreasing load => No.Shorted turns Coil 1 Coil 2 Coil 3 Coil 4 Coil 5

3 Faults on Coil 4 1 Fault on Coil 3

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SONGS U3 GENERATOR RFM Measurements On De-Load

1 Fault on Coil 2

Pole 2

0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70 1 2 3 4 5 6 7 8 9 10 11 Reading decreasing load => No.Shorted turns Coil 1 Coil 2 Coil 3 Coil 4 Coil 5

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SONGS U3 GENERATOR RFM Measurements On De-Load

1 Fault on Coil 4

Pole 3

0.00 0.20 0.40 0.60 0.80 1.00 1.20 1 2 3 4 5 6 7 8 9 10 11 Reading decreasing load => No.Shorted turns Coil 1 Coil 2 Coil 3 Coil 4 Coil 5

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SONGS U3 GENERATOR RFM Measurements On De-Load

2 Fault on Coil 3

Pole 4

0.00 0.50 1.00 1.50 2.00 2.50 1 2 3 4 5 6 7 8 9 10 11 Reading decreasing load => No.Shorted turns Coil 1 Coil 2 Coil 3 Coil 4 Coil 5

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Background to Emergency Response Planning Unit Disaster Recovery and the Concept of Emergency Response Planning

Agenda

Practical implementation of Emergency Response Planning Use of generator diagnostics to identify and monitor risks

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SONGS U3 GENERATOR - Rotor Winding Repair

With the confirmed presence of interturn shorts, particularly with the now

superceded nomex 410 interturn insulation, there was a clear risk of a forced

• utage either by further deterioration in vibration or the development of an

earth fault.

An emergency response plan was developed to ensure the effect of a forced

• utage would be minimized, but also to allow repair in the minimum possible

time if service could be maintained until the next scheduled outage.

A list of components, materials, tooling and specialist labour was developed

to cover all possible scenarios for the repair of the 8 interturn short circuits of unknown severity.

Each scenario was pre-planned, risk assessed and had key decision points

identified to enable the optimum work scope planning to be quickly put in place once the rotor was available.

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SONGS U3 GENERATOR - Rotor Winding Repair

A combined team of ALSTOM and Songs SCE personnel performed a

detailed ‘walk through’ of the project to confirm that all necessary resources from both parties would be available.

An outage organization structure was established, clearly defining roles,

responsibilities and reporting lines to guarantee clear communication and timely decision making.

A new shift pattern was also introduced for the team of skilled craftsmen to

enable continuous 24 hour working whilst ensuring smooth handovers and complete continuity of work.

Site supervision, engineering and management personnel were also

established to enable real time decision making.

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Maintenance Strategy

Emergency Response Plan provided, detailing high risk areas

– Highlighted the lack of spares and tooling. Asbestos abatement etc. – Emergency Repair Kit provided for security in-case of failure. – Repair outage scheduled in October 2004. Workscope to be executed within 14 days (28 day refuelling outage).

Condition Monitoring Established.

– Routine monitoring of insulation condition established to ensure machine continued to operate without major un-planned failure. – Customer prepared for failure just in case.

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Specialist Brazing Equipment

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Retaining Ring Removal

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Rotor Repair FME controlled tent

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Distribution of Shorts

R.H.S. L.H.S.

Exciter End Turbine End Pole 1 Pole 4 Pole 3 Pole 2

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SONGS U3 Generator - Rotor Winding Repair

Pole ‘1’ Exciter End Endwinding Coil 4 Turns 1-2 R.H.S. L.H.S. Exciter End Turbine End

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SONGS U3 Generator - Rotor Winding Repair

Pole ‘1’ Front End Endwinding Coil 4 Turns 6-7 R.H.S. L.H.S. Exciter End Turbine End

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SONGS U3 Generator - Rotor Winding Repair

Pole ‘1’ Front End Endwinding Coil 4 Turns 8-9 R.H.S. L.H.S. Exciter End Turbine End

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SONGS U3 Generator - Rotor Winding Repair

Pole 1 63” in from Rear RHS End Slot Coil 3 Turns 2-3 R.H.S. L.H.S. Exciter End Turbine End

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SONGS U3 Generator - Rotor Winding Repair

Pole 2 Front End Endwinding Coil 2 Turns 1-2 L.H.S. R.H.S. L.H.S. Exciter End Turbine End

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SONGS U3 Generator - Rotor Winding Repair

Pole 3 RearEnd Endwinding Coil 4 Turns 1-2 L.H.S. R.H.S. L.H.S. Exciter End Turbine End

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SONGS U3 Generator - Rotor Winding Repair

Pole 4 Front End Endwinding Coil 3 Turns 5-6 R.H.S. L.H.S. Exciter End Turbine End

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SONGS U3 Generator - Rotor Winding Repair

Pole ‘4’ Front End Endwinding Coil 3 Turns 3-4 R.H.S. L.H.S. Exciter End Turbine End

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SONGS U3 Generator - Rotor Winding Repair

Eight shorted turns sites had been located and repaired. The rotor winding had been reconnected. All of the work had been completed within the programme time

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SONGS U3 Generator - Rotor Winding Repair

Pole 4, Coil 3 Re-Brazed and Re-Insulated. R.S.O. With Windings Re-Connected, Insulation Uncured. 10.18.04

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SONGS U3 Generator - Rotor Winding Repair

Endwinding Insulation cured and end windings repacked. Rotor moved from the clean area tent onto body blocks. R.S.O. With Retaining rings fitted.

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SONGS U3 Generator - Rotor Winding Repair

In line with the interturn fault root cause analysis, there are at least three fault

initiation mechanisms responsible for the observed shorts.

– System Disturbances - Increased turn to turn voltages. – Debris / Contamination / Slow deterioration from as built conditions. – Small burr of unknown origin.

Two step changes in vibration were observed in April and October 2003.

these were coincident with severe system disturbances and are believed to have been caused by the initiation of new shorts or the increased magnitude

• f existing shorts.

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Pole 3

0.00 0.50 1.00 1.50 2.00 1 2 3 4 5 6 7 8 9

Reading decreasing load =>

No.Shorted turns

Coil 1 Coil 2 Coil 3 Coil 4 Coil 5

Pole 4

0.00 0.50 1.00 1.50 2.00 1 2 3 4 5 6 7 8 9 Reading decreasing load => No.Shorted turns Coil 1 Coil 2 Coil 3 Coil 4 Coil 5

Pole 1

0.00 0.50 1.00 1.50 2.00 1 2 3 4 5 6 7 8 9 Reading decreasing load => No.Shorted turns

Coil 1 Coil 2 Coil 3 Coil 4 Coil 5

Pole 2

0.00 0.50 1.00 1.50 2.00 1 2 3 4 5 6 7 8 9 Reading decreasing load => No.Shorted turns Coil 1 Coil 2 Coil 3 Coil 4 Coil 5

SONGS U3 Generator - RFM on re-load post Repair

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SONGS 3 MTG Compensated 1X Shaft Vibration After Richmond Balance (full power), 2 Step Changes (full power), and After C13 Repair (930MW) Zones A,B, and C Acceptance Criteria from ISO per Alstom

1 2 3 4 5 6 7 8 1 3 5 7 9 11 13 15 17 19 21 SHAFT MILS P/P 3Jul01 100% 11-Jan- 05 08-Oct- 03 14apr03 100% 1VH 2VH 3VH 4VH 5VH 6VH 7VH 8VH 9VH 10VH 11VH Richmond Balance Step 1 Step 2 Gen Repair

SONGS U3 Generator - Vibration Comparison

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Comparison to Machine without effective ERP process

To demonstrate the benefits it is necessary to compare to a

similar case, who did not employ an ERP process

– The operator in this case had a generator rotor, with 3 short circuits. – In this case the generator rotor actually failed in service without any ERP to support the failure. – The customer had procured a spare rotor, but had not identified all the miscellaneous components required for the spare to fit the failed machine.

The total duration of the unplanned outage was 50 days.

– Included significant durations to procure spares and tooling to enable the installation of the generic spare rotor. – If an ERP had been in place, all procedures, method statements, risk assessments, spares and tooling would have been in place – Direct comparison to the 28 days for the case study.

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Quantification of Benefits Emergency Response Plans

Pre-planned outage in October 2004, was completed within the

identified outage duration, and was successful in identifying all defects within the rotor (interturn shorts)

From the comparison, we can say that the operator employing

ERP has saved 22 days in unplanned outage duration

– At £25/MWhr, for a 1200MW unit, this equates to a saving of £15.8m in lost revenue.

We can say that the operator who has not employed ERP, has

lost 22 days in unplanned outage duration

– At £25/MWhr, for a 600MW unit, this equates to a £7.9m loss in revenue.

All calculations are based on an average spot price being £25/MWHr (actual revenues will differ subject to individual operator contracts)

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Summary Emergency Response Planning

Identifying the major plant risk areas, providing detail

contingency plans to overcome these risk areas

Joint supplier / customer approach to strategic spares Improves planned and un-planned maintenance outage duration Better identification of spares (stores assessments) Minimises the impact of additional work through identification of

“what-if” scenarios, pre-planning numerous activities

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Plant assessment / recovery flow chart

Operating History Plant improvement OEM knowledge Running Hours Starts / Stops Modifications Inspections Partial discharge Shaft voltages Temperature Stator water Vibration Air gap search coil Plant assessment Fleet knowledge Monitoring Life assessment Risk model Risk assessment Failure scenario Communication Program Resources Tooling Spares

Plant assessment Monitoring Risk assessment ERP

Operating regime Maintenance philosophy Outage planning Spares optimisation

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