June 2012 Project: Image 1

JUNE 14, 2012


A large stationary diesel power plant has been undergoing various life extension projects for base load HFO fuel power generation.

Two Sulzer Z40 engines providing a total of 22 MWe, required replacement of corroded air-cooled radiator fans. The particular challenge for this modification was the lack of available space for additional replacement fans. Northwest Electrical Services LLC worked with the client to engineer and install the following solution:

  1. Retain existing fan frames, and noise silencers
  2. Replace existing two-speed motor design with variable frequency drives for savings of energy during low ambient temperature periods
  3. Modify the system to be direct-coupled motor driven, and remove existing gearboxes to reduce maintenance of obsolete gearboxes
  4. Install new motor control center located near fans in modular construction such that the fan units could be repurposed in other areas of the generating station
  5. Design and install the power system for the radiator farm to include 13.8 KV / 480 VAC transformers in and A/B ring style system
  6. Complete the project with minimal de-rating of the existing units during construction and prior to peak season

Working along with Burmeister Wain Scandinavian Contractor A/S of Denmark for mechanical works, the project included the successful installation and commissioning of:

  • Modular custom MCC enclosure designed and fabricated by Northwest Electrical Services LLC consisting of 36 VFD's in an Ethernet based MCC by Allen Bradley, complete with PLC controls and interface with existing plant systems, HVAC, fire detection alarm and automatic fire suppression
  • Power transformers; ring main switches and all associated power cabling to the station 13.8 KV switchboard
  • Field cabling to all drives, complete with local load break disconnects
  • Fault tolerant control of all drives in the event of communications or PLC failure such that the generator will continue to have adequate cooling capacity
  • Commissioning, training and final documentation

The project was completed and in full operation as of Q2 2012 returning both Sulzer engines to original MCR capacity including overload rating of 110% for two hours.