DMR Case Studies
Potomac Electric Power Company
Potomac Electric Power Company (Pepco) is an investor owned, electric utility serving over 790,000 customers in the Washington DC and surrounding Maryland Counties.
Pepco operated a legacy, analog UHF conventional simulcast system with 25kHz channels. Faced with the FCC narrow-banding mandate, Pepco sought to replace their legacy system with contemporary simulcast equipment with “future proofing” integrated enabling migration to open standards based digital technologies, such as DMR. Pepco also sought to increase system availability by eliminating the single point of failure built-in to traditional simulcast systems with hardware based and fixed control points.
Pepco chose the Selex ES ECOS-D simulcast system. With the ECOS-D automatic Dual Mode analog and digital radio base station, the new simulcast system was compatible with existing user equipment. This also enabled a soft migration from analog FM to DMR. Additional future proofing was obtained with eth 2:1 increase in capacity due to the spectral efficiency inherent in DMR TDMA based technology.
The Automatic Soft Back-up (ASB) feature eliminates single point of failures built-in to traditional simulcast. ASB provides for secondary and tertiary radio base stations at different sites to be designated as “back-ups”. Should the primary control site (master) fail or lose its link, a secondary control site (back-up master) takes over and provides for voting and synchronization within the simulcast system.
NSTAR Gas and Electric
NSTAR is an electric and gas utility headquartered in Boston and operating in Eastern Massachusetts out to Cape Cod and down to New Bedford and Plymouth serving 1.4 million customers.
NSTAR is the result of merging several smaller regional utilities. Each utility prior to the merger operated its own radio system for daily and storm restoration activities – low band, UHF, and VHF. Coordinating work actives across the now merged utilities was difficult and resulted in poor productivity and safety concerns. The systems operated by NSTAR were all wide-band 25kHz so the utility was also faced with the FCC narrow-banding challenge.
NSTAR sought a digital technology based on open standards that would enable the utility to leverage the few frequencies they had at UHF that were exclusive and geographically licensed. NSTAR chose the Selex ECOS-D simulcast system. With ECOS-D simulcast and DMR TDMA 2:1 capacity increase, NSTAR could leverage their scarce frequency resource across the entire utility. Now NSTAR can dispatch work crews across the utility in support of daily operating and storm restoration activities with common and continuous communications.