Case Study | Utility Engineering & Consulting
Electric Transmission FAC-008 Facility Ratings
Network Transmission Owner
Tangibl developed component and facility ratings for the Transmission Planning and Transmission & Substation Engineering organizations of one of the original PJM transmission-owning utilities. To help the Transmission Owner refine its existing ratings processes and procedures and develop a Facility Ratings Methodology compliant with NERC Standard FAC-008-1, Tangibl first developed a ratings template for a typical 138kV line. Upon acceptance of this prototype, and with further refinement and consistent application across thirty-two (32) other 138kV lines, facility ratings were developed for eleven (11) 500kV lines, eighty-eight (88) 230kV lines and forty-nine (49) autotransformers over a three-year period from 2008 to 2010. As the Transmission Owner implemented its T&S capital program, Tangibl updated facilities ratings to reflect component changes and additions resulting from hundreds of minor and major capital projects. In addition to performing facility ratings in a timely manner, Tangibl provided responses to data requests from audits performed by Reliability First Corporation. Finally, Tangibl extended the procedural rigor associated with the Ratings Methodology to 66kV lines, distribution equipment associated with new and expanded substations, underground transmission and distribution cables in duct banks, and new gas-insulated substations for which component ratings had to be established.
Generator Interconnection Switchyard
PJM requested an Independent Power Producer provide facility ratings in accordance with NERC Standard FAC-009-1. The Independent Power Producer’s interconnection switchyard and transmission attachment facilities were incorporated into a separate transmission company. As a relatively recent signatory to the PJM Transmission Owners’ Agreement, the Transmission Owner had to develop its own Ratings Methodology for its 500kV facilities per Standard FAC-008-1. Discussion with the interconnecting network transmission owner resulted in their being referred to Tangibl as an independent consultant. Tangibl developed and documented the Ratings Methodology in a report that included ratings for both 500kV line facilities and the three bus sections associated with the generator step-up transformers that supply the five-breaker 500kV ring bus. The report included PJM rating guides as reference material that formed the basis for this Methodology.
