Start-up and Commissioning

Transformer Services Inc. has completed transformer installation projects throughout the United States and to international customers using products from a wide variety of transformer manufacturers. Our experienced crews can handle any power transformer, large or small, from receiving inspection to complete assembly and testing.

Receiving Inspection
We perform a unit comprehensive inspection upon arrival at transformer locations:

  • Dew Point Test
  • External inspection of transformer and accessories
  • LTC Compartment
  • Control Cabinet
  • Radiator and Radiator Valves
  • Inspect condition of crates
  • Check for positive tank pressure
  • Check for oil leaks
  • Review the Impact Recorder data:
    • Note impact greater than 3 g
    • Contact owner immediately for impacts greater than 5 g
  • Core to ground test
  • Collect sample of bulk oil and test before filling transformer

Complete Assembly
We install all transformer parts and accessories in accordance with manufacturer specifications.

Vacuum Oil-Filling and Dry-Out Process

TSI provides the necessary equipment and technology to meet manufacturer requirements for vacuum degasifying, dehydrating, vacuum oil filling, and on-site dry-out. Our dry-out process removes excess moisture from transformer paper insulation, insulating oil, bushing turrets and other cavities


  • Perform a dielectric test of the oil before filling the transformer
  • Pressure test the unit to ensure the vacuum integrity of the transformer
  • Perform Vacuum Drop test
  • Heat the oil up to 90° C and oil fill under vacuum
  • Fill the transformer with oil at a rate specified by the manufacturer or customer per OEM specifications
  • Apply nitrogen blanket

Upon completion, an oil sample is collected and tested to establish a base for trend analysis.