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GRIP® Level-2

This rotor-in inspection program is designed to fit in a 3-4 day turbine outage window (i.e. steam turbine valve inspection, gas turbine combustion inspection, or hot gas path inspection).

Features:

  • Turbine Generator Stator (TGS) Inspection:
    • 59-Point Visual and Borescope Inspection (as accessible):
      • TGS Frame (for indications of arcing, oxidation, weld cracks, and other evidence of accelerated aging or damage).
      • TGS Connection Ring Assembly (for indications of mechanical dusting or greasing, loose or missing blocks, corona activity, and other evidence of accelerated aging or damage).
      • TGS End Windings (for indications of contamination, mechanical dusting or greasing, loose or missing blocks, corona activity, and other evidence of accelerated aging or damage).
      • TGS Core Iron (for indications of “fretting”, movement of core bolts, lamination looseness, or any other evidence of accelerated aging or damage).
      • TGS Slot Wedge System (for indications of mechanical dusting or greasing, loose and migrating wedges and/or slot fillers, or any other evidence of accelerated aging or damage).
    • Electrical Testing:
      • Armature Winding Copper Resistance Measurements.
      • Armature Winding Insulation Resistance Testing.
      • Armature Winding Polarization Index Testing.
      • Armature Winding High Voltage Testing:
        • DC Stepped Voltage Testing.
        • DC Maintenance Proof Testing (test voltage to be determined by findings of low voltage testing and approved by customer).
        • Power Factor Dissipation and Tip-Up Testing.
        • Corona Camera Examination (as accessible).
      • Stator Slot RTD Resistance Measurement.
      • Stator Slot RTD Insulation Resistance Testing.

 

  • Turbine Generator Rotor (TGR) Inspection:
    • 36-Point Visual and Borescope Inspection (as accessible):
      • Retaining Rings (for indications of surface pitting, oxidation, and/or cracks, movement or fretting against fits, electrical arcing, or any other evidence of accelerated aging or damage).
      • Main Field End Windings (for indications of contamination, copper elongation, deformation, or cracking, migration or turn or ground insulation components, or any other evidence of accelerated aging or damage).
      • Rotor Body Wedges (for indications of looseness and/or fretting, electrical arcing, or any other evidence of accelerated aging or damage).
      • Rotor Body Forging (for indications of cracking, arcing, overheating, or any other evidence of accelerated aging or damage).
      • Coupling(s) and Journals (for indications a significant wear, galling, wiping, stress fractures, or any other evidence of accelerated aging or damage).
    • Electrical Testing:
      • Main Field Winding Copper Resistance Measurement.
      • Main Field Winding Insulation Resistance Testing.
      • Main Field Winding Polarization Index Testing.
      • Main Field Winding AC Impedance Testing.
      • AC Pole Drop Testing (as accessible).

 

  • Turbine Generator Exciter (TGE) Inspection:
    • 14-Point Visual and Borescope Inspection (as accessible):
      • Exciter Windings (for indications of contamination, armature band condition, overheating, or any other evidence of accelerated aging or damage).
      • Collector Ring Assembly or Brushless Exciter Assembly (for indications of contamination, looseness and/or fretting, arcing and/or burning, excessive wear, or any other evidence of accelerated aging or damage).
      • Brush assembly (for indications of contamination, worn insulators, carbon brush condition, or any other evidence of accelerated aging or damage).
    • Electrical Testing:
      • Brushless Exciter Armature Insulation Resistance Testing.
      • Brushless Exciter Stationary Field Insulation Resistance Testing.

 

Benefits:

  • Reveals additional data on armature winding insulation integrity to more accurately assess life and future maintenance requirements.
  • Reveals assessment of end winding stability (resonance conditions can be immediately corrected to avoid premature winding deterioration).
  • Record of core tightness.

More complete documentation for planning future maintenance.

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