Alstom Technology Limited

Florida Power & Light Company

Michael J Putt

James N Blake

David L Smith

Alan Baker

Benny Naranjo

Joseph H Schaeffer

A power distribution system adapted for high current fault management during a fault event utilizes reclosing switches configured for a quick-slow-quick reclosing sequence in which the reclosing switch initially responds to the fault condition by tripping open, and then after a delay recloses for a first duration of time (slow) prior to tripping open. After another delay, the reclosing switch recloses for a second duration of time (quick) that is less than the first duration of time prior to tripping open for an indefinite interval. When installed in new segments or retrofitted in place of a fuse, reclosing switches configured with quick-slow-quick reclose timing allows for reduction of downstream customer outages, reduced IT exposure for elements upstream of a fault event and a reduction in the duration of voltage sags experienced by customers during fault events while allowing for improved fault management configurations of the power distribution system.

Coordinated reclosing in a power distribution system

Systems and methods according to these exemplary embodiments provide for methods and systems related to optical current sensors used to monitor standby power transformers, specifically fiber optical current and voltage sensors and, more particularly, to applications involving filters for use in such sensors, such as frequency tracking comb filters. According to one embodiment, a method for monitoring a connection condition of a stand by power transformer includes the steps of measuring a current flowing through a high voltage side of the standby power transformer using at least one optical current sensor disposed proximate to a current flow path of the high voltage side, using a comb filter to filter the measured current, determining whether the filtered, measured current is less than a predetermined threshold value; and generating an alarm indication that the high voltage side of the standby power transformer is unconnected.

Power transformers using optical current sensors

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Palm City, FL, United States of America

Michael J Putt