Lightweight Power System Ready to Fly

The U.S. Air Force and Army needed a lightweight electrical power system that could be transported by air to serve provisional bases. And they wanted switchgear for their new deployable power generation and distribution system that could be stacked two-high to save space aboard transport aircraft and in storage.

09/01/2003


The U.S. Air Force and Army needed a lightweight electrical power system that could be transported by air to serve provisional bases. And they wanted switchgear for their new deployable power generation and distribution system that could be stacked two-high to save space aboard transport aircraft and in storage.

They also specified a special steel skid for permanently mounting the gear. The skid would be integral with the enclosure, serving as both a pad and lifting support. The gear would need to pass the MIL Spec E-810 20-hr. shaker-table vibration test, verifying that stacked units could withstand 10,000 miles of travel aboard military aircraft. It would also need to pass tests verifying that switchgear performance is not affected after the gear has been subjected to low pressure at an altitude of 40,000 ft.

The engineering contractor for the new system chose an underground distribution switchgear for primary switching and secondary distribution that would be easy to operate and require minimal training of ever-changing military personnel. Moreover, the SF6-insulated unit that they specified would be small and light weight—ideally suited for airlifting.

Multiple units of a manually operated 15.5-kV model were furnished to switch and protect loads fed by 920-kW generators. All of the units have a 600-amp continuous current rating and 16-kA short-circuit and fault-interrupting capabilities. Each unit includes two load-interrupter switch ways and four fault-interrupter ways. Optional voltage indicators are also included.

The switchgear enclosure was completely redesigned and outfitted with the requisite integral steel skid. The skid and enclosure frame utilize heavy-duty steel I-beams and channels. Four alignment pins at the top corners of the enclosure facilitate stacking of the units. Stacked units are lifted by eyebolts on the skid frame.

Channels at the bottom allow forklift handling; reinforced tabs at the lower corners of the skid allow the gear to be dragged along the ground. Turnbuckles, attached to eyebolts on front and rear sides of the skid, hold stacked units together during transport. Plates, attached to the floor of the enclosure, protect the switchgear during transport and storage and can be removed for cable entry while the gear is in use.

The switchgear passed the rigorous shaker table tests imposed by the specifications. And the special design retained all the unique features of the standard-production model. To date, several of these units have been sent to bases overseas. Others are scheduled for shipment in the near future.





No comments
Consulting-Specifying Engineer's Product of the Year (POY) contest is the premier award for new products in the HVAC, fire, electrical, and...
Consulting-Specifying Engineer magazine is dedicated to encouraging and recognizing the most talented young individuals...
The MEP Giants program lists the top mechanical, electrical, plumbing, and fire protection engineering firms in the United States.
Combined heat and power; Assessing replacement of electrical systems; Energy codes and lighting; Salary Survey; Fan efficiency
Commissioning lighting control systems; 2016 Commissioning Giants; Design high-efficiency hot water systems for hospitals; Evaluating condensation and condensate
Solving HVAC challenges; Thermal comfort criteria; Liquid-immersion cooling; Specifying VRF systems; 2016 Product of the Year winners
Driving motor efficiency; Preventing Arc Flash in mission critical facilities; Integrating alternative power and existing electrical systems
Putting COPS into context; Designing medium-voltage electrical systems; Planning and designing resilient, efficient data centers; The nine steps of designing generator fuel systems
Designing generator systems; Using online commissioning tools; Selective coordination best practices
As brand protection manager for Eaton’s Electrical Sector, Tom Grace oversees counterfeit awareness...
Amara Rozgus is chief editor and content manager of Consulting-Specifier Engineer magazine.
IEEE power industry experts bring their combined experience in the electrical power industry...
Michael Heinsdorf, P.E., LEED AP, CDT is an Engineering Specification Writer at ARCOM MasterSpec.
click me