The Utility Source February 2019 - Page 12

Improving on the Original Westinghouse Iso-Phase Bus Design Not only does the Westinghouse design live on, but iterative improvements to insulators, mountings and housings make this IPB design even more rugged and reliable Isolated-phase bus (IPB) systems are the critical first link in the power transmission chain.  As a highly reliable method of construction for moving bulk electrical power, Iso Phase Bus Duct systems are the super highways that carry a power plant’s very large amperage between the generator’s output bushings and its associated main step-up (GSU) transformer.  IPBs are typically rated from 6,000 to 45,000 amps with lower amperage tap connections to excitation and auxiliary transformers as may be needed. Given its critical role, IPBs must provide a very high degree of rugged reliability and fault avoidance to keep power generation facilities operational without outages, downtime or severe equipment damage.  Failure is simply not an option. By its very definition, IPBs are designed to provide protection from faults by carrying each phase of current on a conductor mounted within its own separately enclosed, grounded metal housing.  The conductors are usually hollow aluminum tubes supported within the housing on, hung or between stand-off insulators.  Due to the heat generated, the housings may be self-cooled or force-cooled so that the IPB always operates within the maximum allowable top temperature as specified by IEEE/ANSI. For decades, IPBs have been based on original designs from the major OEMs such as General Electric (GE) and Westinghouse that dominat- ed the marketplace.  Despite the exit of both GE and Westinghouse from the IPB market, some of the original designs live on through direct successor companies.  One such successor company is Crown Electric Eng. & Mfg. LLC of Middletown Ohio. Originally founded by the former Westinghouse plant General Manager and Materiel Manager, Crown Electric engineers, designs, fabricates, installs, maintains, repairs and uprates Iso Phase Bus and large bus duct systems. After purchasing ownership from Crown Electric’s founding generation, the current owners of Crown invested heavily to build and equip the newest most modernized IPB factory in North America in Middletown, Ohio – just a short drive from the old Westinghouse location. As a successor of the Westinghouse heritage - Crown Electric has continued to improve on the original Westinghouse design with refine- 10 TUS Magazine • February ‘19