RFP_1100_MMH3038_ATT_3_v1.pdf

ATTACHMENT 3

STEAM TURBINE D-11 MAINTENANCE

Contractors Planned Maintenance Scope of Work for Steam Turbine

Minor Inspection:

Provide lump sum pricing for the following turnkey services including project management, technical direction, craft labor supervision, craft labor, scaffolding, and any special tools (cranes, crane operator, forklifts, lights, air compressors and fuel) and equipment required to perform a minor inspection. Assume a four-week 24/7 schedule.

1) Perform a Minor Inspection on a GE D-11 Steam Turbine

a) Remove and replace insulation and lagging (turbine enclosure).

b) Valves:

i) Main Stop/Control Valves (2)

(1) Disassemble steam side for inspection

(2) Perform contact check on seats and discs

(3) Record clearance and run out of stem

(4) Clean stems and bushings and record clearances and reassemble

(5) Visually inspect disc, seat, and strainer (NDE valve seat and seal weld)

ii) Combined Reheat Valves (2)

(1) Disassemble steam side for inspection

(2) Visually inspect disc, seat, and strainer (NDE valve seat and seal weld)

(3) Perform contact check on seats and discs

(4) Record clearance and run out of stem

(5) Clean stems and bushings and record clearances and reassemble.

iii) Non-Return Valve

(2) Visually inspect disc, seat, and anti-rotation pin.

(3) Perform contact check on seats and discs

iv) Low Pressure Steam Stop Valve (1)

(2) Visually inspect disc and seat

(3) Perform contact check on seats and discs

v) Low Pressure Steam Admission Valve (1)

(2) Visually inspect disc and seat

(3) Perform contact check on seats and discs

c) Bearing Inspection

i) For all six (6) journal bearings and the thrust bearing:

(1) Disassemble

(2) Remove

(3) Clean

(4) Visually inspect

(5) Record clearances and conditions (including ball seat contact and pinch checks)

(6) NDE (Ultrasonic inspection) for babbit bonding

(7) Reassemble

2) Perform a Minor Inspection on a 7FH2 Generator

a) Include all disassembly and reassembly required to perform the inspection.

b) Shutdown (AE)

i) Depressurize and purge generator to air.

ii) Measure mechanical run-out of collector rings while on turning gear.

iii) Shutdown and tag out lube oil and seal oil pumps (ensure that generator is electrically isolated and grounded.

c) Generator Climate Control

i) Contractor shall supply all climate control equipment required to maintain a warm dry environment for the generator rotor and stator. This includes all required hoses, scaffold, tarps, and dehumidifier equipment.

d) Generator Disassembly

i) Turbine End

(1) Unbolt and remove the roof of the collector cab.

(2) Remove bearing caps and outer oil deflectors (both ends).

(3) Remove the upper half bearings, upper half hydrogen seals, and upper half inner oil deflectors (both ends)

(4) Disconnect and remove all piping and wiring from both outer end shields.

(5) Remove the upper half outer end shield.

(6) Remove the lower half hydrogen seals and the lower half inner oil deflectors (both ends).

(7) Remove the upper half inner end shield.

ii) Collector End

(1) Unbolt and remove the roof of the collector cab.

(2) Remove bearing caps and outer oil deflectors (both ends).

(3) Remove the upper half bearings, upper half hydrogen seals, and upper half inner oil deflectors (both ends).

(4) Disconnect and remove all piping and wiring from both outer end shields.

(5) Remove the upper half outer end shield.

(6) Remove the lower half hydrogen seals and the lower half inner oil deflectors (both ends).

(7) Remove the upper half inner end shield.

e) Generator Clean and Inspect

i) Clean and inspect generator parts

(1) Clean bearing assemblies, oil deflectors, hydrogen seals, fan blades, and end shields.

(2) Visually inspect bearing assemblies, oil deflectors, hydrogen seals, and fan blades for damage, pitting, or insulation breakdown.

(3) Take and record (as found) readings for bearings, journals, hydrogen seals, and oil deflectors.

(4) Hydrogen seals shall have a 100% blue contact check.

ii) Clean and inspect brush holding rigging.

(1) Clean brush holding rigging.

(2) Visually inspect brush rigging.

iii) Generator visual inspection

(1) Inspect stator core and windings, field wedges, surface, and inner ends of retaining rings.

(2) Inspect stator end windings, field coil end turns, and upper frame high voltage extension bus leads and connections.

iv) Perform MAGIC (Miniature Air Gap Inspection Crawler) robotic visual inspection with the stator and field gap to inspect stator core laminations, stator wedges, and surface on the inboard ends of the retaining rings.

v) Disassemble journal bearings and inspect:

(1) Visually inspect

(2) Take and record as found clearances including ball seat contact and pinch checks.

(3) Check for babbit un-bonding using ultrasonic inspection.

(4) Measure insulation resistance on collector end.

vi) Brush Rigging and Collector Rings

(1) Inspect for proper clearance between brush holder and collector rings.

(2) Inspect for pitting, threading, grooving wear on collector rings.

vii) Stator Winding

(1) 10-minute Insulation Resistance Measurement and Polarization Index

viii) Frame

(1) Check tightness of hold down bolts and jacking bolts.

(2) Check that compartment interface seals are watertight and intact.

(3) Check that the rubber expansion joint in the load compartment.

ix) Rotor

(1) 10-minute Insulation Resistance Measurement and Polarization Index.

x) Alignment

(1) Record vibration data prior to shut down.

xi) Turning Gear

(1) Inspect tooth contact for tooth wear or damage.

(2) Check that oil feed nozzles are clean and free or foreign matter.

xii) Cooler

(1) Inspect for air leakage at frame sealing

(2) Inspect for cleanliness of tubes on air side and water side.

f) Reassembly

i) Collector End

(1) Roll in lower half bearing and perform twist and tilt check and check bearing clearances.

(2) Assemble the upper-half end shield.

(3) Make a hydrogen tight seal on the end shield. Pump Dow-Corning Q4-2805 into the sealing grooves. Contractor to supply sealant with current expiration date.

(4) Perform a contact check on the horizontal joints of oil deflectors.

(5) Assemble the inner oil deflector

(6) Assemble the hydrogen seal housing.

(7) Assemble upper-half bearing.

(8) Assemble outer oil deflector in the bearing cap.

(9) Assemble bearing cap.

(10) Check radial clearances

(11) Install the roof of the collector cab.

ii) Turbine End

(1) Roll in lower half bearing and perform twist and tilt check and check bearing clearances.

(2) Assemble the upper-half end shield.

(3) Make a hydrogen tight seal on the end shield. Pump Dow-Corning Q4-2805 into the sealing grooves.

(4) Perform a contact check on the horizontal joints of oil deflectors.

(5) Assemble the inner oil deflector.

(6) Assemble the hydrogen seal.

(7) Assemble upper-half bearing.

(8) Assemble outer oil deflector in the bearing cap.

(9) Assemble bearing cap.

(10) Check radial clearances.

g) Test

i) After generator is re-assembled, Vendor shall run a 24-hour air test to ensure that the generator is airtight. This test shall be in accordance with OEM standards.

ii) Provide a written report with a summary of the work including all recorded clearances.

3) Perform a Major Inspection on a GE D-11 Steam Turbine

a) Include all disassembly and reassembly required to perform the inspection.

b) Turbine:

i) Remove lagging and heat retention material.

ii) Remove horizontal joint bolting, clean, and inspect.

iii) Remove shell and record rotor clearances.

iv) Disassemble journal bearings and thrust bearing, clean, visually inspect, record clearances and conditions, including ball seat contact and pinch checks.

v) Disassemble coupling and remove turbine motor.

vi) Remove all diaphragms, blast clean, and visually inspect, NDE and reassemble, including a check of axial crush pins and side clip, and a horizontal drop check.

vii) Visually inspect shell, including inner surfaces and ledges, first stage nozzle removal, repair, and re-assembly, if required.

viii) Disassemble packing, record condition of springs and packing, clean visually inspect, sharpen teeth as required, reassemble, and record final clearances.

ix) Disassemble oil deflectors, clean, visually, inspect, reassemble, and record final clearances.

x) Blast clean turbine rotor, visually inspect, record conditions, NDE, reinstall and record rotor clearances.

xi) Check coupling alignment and make-up coupling.

xii) Reassemble shells, install, and stretch horizontal joint bolts.

xiii) Install heat retention material and lagging.

c) Valves

i) Valve Actuators

(1) Steam Valves Hydraulic Actuators

(a) External, visual inspection of operating actuators

(b) Replace rod seals and wipers, if necessary.

(c) Inspect and change servo strainers.

(2) Hydraulic Pumping System

(a) Drain, clean, and refill tank. Owner responsible for handling hydraulic fluid drained from tank.

(b) Inspect and change accumulators.

(c) Check pump operations and motor alignment.

(d) Check compensators.

(e) Check and adjust relief valves as required.

(f) Change filters, clean screens, reset indicators.

(g) Clean and leak check EHC coolers.

(3) Turbine Control Components

(a) Visually inspect linkage and adjust.

(b) Check and adjust oil trip nozzle.

(c) Clean and set gap on speed pickups.

(d) Clean and inspect thrust bearing wear detector.

(4) Shaft Grounding Device

(a) Check brushes and set holder clearances.

(5) Lube Oil System

(a) Note: Oil tanks will require draining by owner, prior to inspection. Oil draining and handling is not part of the Contractor’s scope.

(b) Clean and inspect oil tank.

(c) Main oil pump: disassemble, clean, inspect, record clearances and conditions and reassemble.

(d) Remove cooler heads, clean tube sheets and tubes with brushes, inspect and reassemble.

(6) Auxiliary Oil Pumps

(a) Disassemble pumps, clean, visually inspect, record clearance and conditions and reassemble.

(7) Turning Gear

(a) Examine gears for wear and condition, clean and check operation (motor inspection not included).

(8) Steam Seal Gland

(a) Steam Seal Regulator

(i) Disassemble and visually inspect pilot valve, piston, and cylinder.

(ii) Disassemble bellows and pivot rod and inspect

(iii) Disassemble feed and dump valves and inspect

(iv) Reassemble and adjust as required

(b) Spray Chamber

(i) Disassemble, clean, and inspect inlet water nozzle and strainer

(ii) Adjust butterfly valves

(c) Gland Exhauster

(i) Disassemble blower, clean, inspect, record clearances and conditions and reassemble (motor inspection not included)

(d) Turbine Supervisory Instrumentation

(i) Visually inspect and calibrate devices

(e) Start-up and Checkout

(i) Operational checks after completion of overhaul shall be made jointly with owner personnel.

(ii) prior to start-up.

1. Check foundation for interference for expansion restrictions.

2. Check all trips and control component operating devices.

3. Check operation of oil pumps.

4. Check thrust failure device for alarm and trip.

5. Check calibration of TSI system.

6. Check calibration of Mark VI turbine control system.

(iii) During Start-up:

1. Check vibration readings.

2. Verify low speed stop settings.

3. Verify high speed stop setting.

4. Verify pre-emergency governor.

5. Verity regulation.

6. Check expansion of unit at standard.

(iv) Operation (with unit synchronized)

1. Check vibration readings: if required, a balance program to correct a balance problem will be provided as Extra Work.

2. Check performance data at same loads prior to shut down.

(v) Final Setting

1. After operating Unit at a minimum of 25% load for a period of four hours, the over-speed trip operation will be performed, adjusting as necessary.

4) Perform a Major Inspection on a 7FH2 Generator

a) Shutdown (AE)

i) Depressurize and purge generator to air.

ii) Measure mechanical run-out of collector rings while on turning gear.

iii) Shutdown and tag out lube oil and seal oil pumps (ensure the generator is electrically isolated and grounded).

b) Generator Climate Control

i) Contractor shall supply all climate control equipment required to maintain a warm dry environment for the generator rotor and stator. This includes all required hoses, scaffold, tarps, and dehumidifier equipment.

c) Generator Disassembly

i) Remove the roof of the collector cab.

ii) Remove the rear door panels and the center door sill angle (at floor level) of the collector cab.

iii) Uncouple and remove the turning gear and the flex coupling.

iv) Remove collector chimney silencer.

v) Withdraw the collector inlet silencer and lower the field exciter cables into the duct below the cab deck.

vi) Remove the brush rigging and exciter.

vii) Remove shaft ground brushes and vibration probes (AE).

viii) Remove upper half of the load compartment and load compartment silencer.

ix) Remove bearing caps and outer oil deflectors (both ends).

x) Remove the upper half bearings, upper half hydrogen seals, and upper half inner oil deflectors (both ends).

xi) Disconnect and remove all piping and wiring from both outer end shields.

xii) Remove the upper half outer end shield.

xiii) Remove the lower half hydrogen seals and the lower half inner oil deflectors (both ends).

xiv) Remove inlet vanes from the upper half inner end shields and remove the upper half inner end shield.

xv) Remove fan blades from rotor.

xvi) Uncouple the generator from the turbine.

xvii) Remove any remaining equipment which protrudes above the top surface of the cab deck plate.

xviii) Disassemble and remove the walkway from the rear of the cab.

d) Remove the rotor from the stator

i) Provide all tools, equipment, platform, and lifting equipment required to remove the generator rotor from the stator.

ii) Remove the generator rotor, inspect, and reinstall in accordance with OEM guidelines.

e) Generator Clean and Inspect

i) Clean and inspect generator parts

(1) Clean bearing assemblies, oil deflectors, hydrogen seals, fan blades, and end shields.

(2) Visually inspect bearing assemblies, oil deflectors, hydrogen seals, and fan blades for damage, pitting, or insulation breakdown.

(3) Take and record (as found) readings for bearings, journals, hydrogen seals, and oil deflectors.

(4) Hydrogen seals shall have a 100% blue contact check.

ii) Clean and inspect brush holding rigging

(1) Clean brush holding rigging.

(2) Visually inspect brush rigging.

iii) Generator visual Inspection

(1) Inspect stator core and windings, field wedges, surface, and inner ends of retaining rings.

(2) Inspect stator end windings, field coil end turns, and upper frame high voltage extension bus leads and connections.

iv) Disassemble journal bearings and inspect:

(1) Visually inspect.

(2) Take and record as found clearances including ball seat contact and pinch checks.

(3) Check for babbit un-bonding using ultrasonic inspection.

(4) Measure insulation resistance on collector end.

v) Brush Rigging and Collector Rings

(1) Inspect for proper clearance between brush holder and collector rings.

(2) Inspect for pitting, threading, grooving wear on collector rings.

vi) Stator Winding

(1) 10-minute Insulation Resistance with Polarization Index

(2) Winding Copper Resistance

(3) RTD Resistance Check and Insulation Resistance

(4) DC Leakage

(5) DC Hi-pot (if necessary)

(6) Cleanliness of end windings

(7) Evidence of corona

(8) Distortion or overheating

(9) Broken ties/laminations

(10) Evidence of end winding movement

(11) End winding support hardware

(12) Internal cleanliness

(13) Strip heaters clean and operational

(14) Damaged punchings (laminations or core iron)

(15) Stator wedge system (inspection and tap test)

(16) Cleanliness core (blow with clean compressed air)

(17) Hydrogen Coolers (inspect and clean)

(18) EL-CID (Electromagnetic Core Imperfection Detector) Test

(19) Core Loop Test (required if repairs are made to stator core)

vii) Frame End

(1) End winding provisions clear

viii) Rotor

(1) 10-minute Insulation Resistance with Polarization Index

(2) Winding copper resistance

(a) AC Impedance Test

(b) Pole Balance Test

(c) Retaining ring damage (NDE)

(d) Cleanliness of end winding

(e) Evidence of end winding movement (using a borescope if necessary)

(f) Wedge movement

(g) Check balance weights on field

(h) Fan blade damage or erosion

(i) Indication of overheating

(3) Liquid Level Detector

(a) Proper Operation

(4) Shaft Sealing System

(a) Excessive seal ring clearance

f) Reassemble Generator

i) Install rotor in stator

(1) Install the belly pan in the stator with fish paper between belly pan and stator core.

(2) Position the rotor on rolling supports as when it was removed from the stator.

(3) Assemble the coupling shoe and secure it to the shaft. Assemble rigging for pulling rotor through stator.

(4) Pull the rotor into the stator until the coupling shoe is close to the end of the stepped punchings (step down iron) on collector end.

(5) Raise the rotor using the roller supports jacking screws until the coupling shoe clears the stator core and is level.

(6) Pull the rotor into the stator until the coupling shoe has completely passed the stepped punchings (step down iron).

(7) Remove the top half of the body rolling support.

(8) Lower the body rolling support using the jacking screws until the weight of the rotor is supported on the coupling shoe and the collector end rolling support.

(9) Disassemble and remove the body rolling support.

(10) Pull the rotor into the stator until the first rotor shoe can be inserted past the stepped punchings (step down iron).

(11) Raise the collector end of the rotor using jacking screws of the collector end rolling support and insert the first rotor shoe between the rotor body and the belly pan.

(12) Lower the collector end of the rotor slightly to take the weight off the coupling shoe and put it on the rotor shoe.

(13) Pull the rotor through the stator until the coupling is between the stator core and the lower half inner end shield (turbine end). Remove the coupling shoe.

(14) Continue pulling the rotor into the stator until the collector end rolling support reaches the front edge of the cab deck.

(15) Raise the collector end of the rotor slightly with the rolling support and insert the second rotor shoe past the stepped punchings (step down iron) between the rotor body and the belly pan.

(16) Jack the collector end of the rotor down until the rolling support is unloaded and the rotor weight is on the two rotor shoes.

(17) Remove the roller support.

(18) Assemble the shaft support sling to the collector end of the stator frame.

(19) Install the turbine end lower half outer end shield.

(20) Raise the rotor slightly above centerline using the shaft jacking device on the turbine end and the shaft support sling on the collector end.

(21) Remove the rotor shoes, belly pan, fish paper, and protective shim (belly pan) from stator.

(22) Install the collector end lower half inner end shield and guide vanes.

(23) Install the collector end lower half outer end shield.

(24) Roll in the lower bearing halves.

(25) Lower the rotor onto the bearings.

(26) Reinstall the fan blades (both ends). Use new locking plates.

(27) Reinstall the upper half inner end shields.

(28) Reinstall the lower half hydrogen seals and lower half inner oil deflectors (both ends).

(29) Reinstall the upper half bearings, upper half hydrogen seals and upper half inner oil deflectors (both ends).

(30) Reinstall the bearing caps and outer oil deflectors (both ends).

(31) Reconnect all piping and wiring to both outer end shields.

(32) Remove the outer end shield support brackets.

(33) Reinstall the upper half load compartment and load compartment silencer (turbine end).

(34) Reinstall the shaft grounding brushes and vibration sensors (AE).

(35) Reconnect the collector inlet silencer, and field exciter cables.

(36) Reinstall the collector chimney silencer, collector cover, and collector fan.

(37) Reinstall the turning gear and reconnect the flex coupling.

(38) Remove the bridge support brackets and reinstall the cab center door panel sill angle.

(39) Reinstall the cab door panels, walkway, and roof.

(40) Recouple the generator rotor to the turbine load coupling.

(41) Re-install brush rigging items and ensure collector ring brushes are properly seated.

g) Test

i) After generator is reassembled run a 24-hour air test to ensure that the generator is airtight.

This test shall be in accordance with OEM standards.