Power sequencing approach to fault isolation in dc systems: Influence of system parameters

• Published in: 2010 IEEE Energy Conversion Congress and Exposition pp. 72 - 78
• Main Authors: Cairoli, P, Dougal, R A, Ghisla, U, Kondratiev, I
• Format: Conference Proceeding
• Language: English
• Published: IEEE 01.09.2010
• Subjects: Capacitance; Capacitors; Circuit breakers; Circuit faults; Contactors; Converters; converters control; Fault currents; fault protection; MVDC systems; power electronics; power sequencing
• ISBN: 1424452864; 9781424452866
• ISSN: 2329-3721
• DOI: 10.1109/ECCE.2010.5618075

We show that medium-voltage dc power buses can be protected against short circuit faults by coordinating the action of a converter that supplies power to the bus with the action of contactors that are used to reconfigure the bus connections. Following a fault, the bus is de-energized (so there is no large current to interrupt), one or more contactors are reconfigured, and the dc bus is then reenergized. For a typical industrial dc bus, we show that it is possible to execute this de-energize-reconfigure-re-energize process 10 times faster than an AC bus can be protected and reconfigured using traditional circuit breakers. We show how the de-energizing and reconfiguring times depend on the output capacitance of the main converter and on the distance to the fault, and we show how to size each hold-up capacitor so that loads on unfaulted circuits can ride through the process uninterrupted.