In-Field Technical Services

Transformers

  • TTR - Verifies Ratio, Polarity and Tap Changer Operation for Acceptance and Maintenance Testing Intervals
  • POWER FACTOR -Measuring capacitance and dissipation power factor determines insulation condition in the windings and bushings.
  •    WINDING RESISTANCE - Measuring the resistance of the windings assures that the connections are correct. This also checks for any changes in tap changers from the mechanical movement of a contact from one position to another.
  •    EXCITATION CURRENT TEST - Winding Faults, Shorts, Open Circuits ,Core Ground Problems
  •    Inspect and Test all GAUGES, ALARMS, AND TRIP CIRCUITS
  •    Test SUDDEN PRESSURE RELAY
  •    CURRENT TRANSFORMERS - Test with Omicron CT Analyzer and Megger
  •    Pull Oil Samples for DGA, MOISTURE, AND DIELECTRIC once a year
  •    Check NITROGEN SYSTEM for proper operation

 

Bushings

  • POWER FACTOR – Tests for Overall Power Factor and Capacitance.  Measurements are compared to nameplate data and checked at each scheduled maintenance interval for degradation.

 

Load Tap Changers

  • TTR- All Tap Positions
  • Clean TAP CHANGER COMPARTMENT
  • Check all CONTACTS for wear and replace as necessary.
  • Check OPERATING MECHANISM, CONTROL, POSITION INDICATOR, LIMIT SWITCHES AND COUNTER for proper operation.
  • POWER FACTOR
  • HI-POT if equipped with vacuum bottles
  • Install new DOOR GASKET AND NEW OIL

 

 No-Load Tap Changers

  • Check for LEAKS
  • Test with TTR needed or proper operation
  • WINDING RESISTANCE for connections

 

Radiators

  • Check for LEAKS
  • Check VALVE

 

 Other Station Equipment

  • CONTROL CABINETS – Change electro- mechanical to solid state relays
  • CT’s and PT’s- Megger ,Ratio, Polarity , CT Analyzer , Excitation Knee Point
  • LIGHTNING ARRESTORS –  Power Factor Tests
  • GROUND SWITCHES – Megger and Timing
  • CABLES- Megger and Hi-Pot
  • OIL PROCESSING
  • Envirotemp™ FR3™ RETROFILLING
  • INFRARED SCAN - Check Hot Spots in all Equipment-Transformers, Breakers, Air Break Switches, Circuit Switches

 

Reclosers

  • MEGGER
  • HI-POT
  • CONTACT RESISTANCE
  • Control TIMING TESTS
  • Control INSTALLATION
  • Control UPGRADES
  • TRIP CHECKS

 

Oil Circuit Breakers

  • MEGGER
  • POWER FACTOR Unit and Bushings
  • BREAKER ANALYZER – Tests Timing, Travel and current draw on trip and close coils
  • CONTACT RESISTANCE
  • Check AIR COMPRESSOR
  • Check or Change COMPRESSOR OIL
  • Check COMPRESSOR V BELT
  • Test AIR CUT OUT SWITCHES

 

SF6 Breakers and Circuit Switchers

  • MEGGER
  • POWER FACTOR unit and Hot Collar Bushings
  • BREAKER ANALYZER – Tests Timing, Travel and current draw on trip and close coils
  • Check ALARMS AND TRIP CIRCUITS
  • Check SF6 GAS for DENSITY AND MOISTURE

 

Controls

  • ELECTRO-MECHANICAL RELAYS – Test with Omicron CMC 356
  • SOLID STATE RELAYS – Test with Omicron CMC 356
  • RELAY UPGRADES

 

Regulators

  • MEGGER
  • POWER FACTOR
  • HOT COLLAR BUSHINGS
  • WINDING RESISTANCE on all Taps
  • Test CONTROLS for proper Operation
  • CONTROL UPGRADES

 

Field Repair

  • Transformer leaks
  • Bushings Replaced
  • Fuses Replaced
  • Oil Retrofill
  • Radiators
  • Gauges