AC Reserve Energy Systems - Performance During Blackouts

A study of 314 AC reserve power plants in Bell System offices involved in 5 major blackouts in 1977-1978, revealed only 2 plant failures resulting in loss of telephone service for a 0.6% failure rate. There were, however, a total of 51 plants experiencing troubles which required operator action to correct. The proliferation of telecommunications equipment in unattended locations with an increasing dependency on AC power, will require a higher order of reliability from the AC reserve energy systems. Data shows rigorous design and perfomance standards result in improved operation during power failures. Also indicated is the need for more thorough routine excercising to insure the system is capable of operating without assistance for extended periods of time.