Project Detail

Weldon Frequency Conversion

Mattawamkeag, ME

Scope of Work

Cianbro was the EPC contractor for the complete turbine generator rebuild, conversion of the generating capacity, and balance of plant equipment from 40 to 60 Hz.

Project Details

  • In partnership with GLHA, a unique EPC (Engineer, Procure, and Construct) Contract was negotiated. Together, specifications were bid and negotiated with GE Hydro for the new turbine runners, rotors, and generator rewinds
  • Specified, bid and negotiated equipment purchase orders with ABB for medium voltage arc resistant switchgear and with Eaton Electrical for generator excitation systems
  • Completed mechanical disassembly/inspection of four turbine generators
  • Reassembled turbine generators with new runners
  • Rewound four generator stators and installed new rotors to facilitate frequency conversion
  • Installed new switchgear, auto-synchronizer, local operator control cabinets, excitation cabinets, excitation transformers, station service transformer and motor control center
  • Refurbished the existing mechanical Woodward Governor
  • Updated balance of plant equipment including air compressors, pumps, hoist, gate drives, station lighting and station heat
  • Modified the bearing cooling water system
  • Installed new tailrace monorail and gates
  • Performed all electrical completion checkout and commissioning

Lean, Innovative, and Unique Project Solutions

The unique project schedule encompassed the spring runoff flows, peak power pricing in the winter months and summer, and FERC-mandated fish flow times during which certain units must be in operation. In cooperation with GLHA, Cianbro invested in several creative methods to install new systems while existing ones continued to operate allowing GLHA to continue production and transmission of both 40 and 60 horsepower. This added project value by allowing GLHA to maximize their power production.