A failure of an individual substation, bus, or circuit within the electrical distribution system can affect process equipment and utilities, resulting in multiple releases to the disposal system. In some cases a partial power failure may result in a larger overall load to the disposal system or (more commonly) to a single collection line within the system than a total failure.
Determination of Credibility
A fault, inadvertent operation of circuit breakers, or a mechanical failure can lead to a localized loss of electrical power within the distribution system. Credit for automatic or manual switching of power supplies is generally not taken when determining the credibility of a failure. Facility electrical personnel should be consulted when evaluating potential modes of failure.
Determination of Impact on the Collection and Disposal System
The impact on the disposal system is determined in the same manner as described for total power failure. Additional consideration should be given to equipment that continues to be supplied power by unaffected portions of the electrical distribution system.