DC-DC converter plants and their ability to clear distribution fuses

Accidental faults in the distribution circuits of DC-DC power converter plants can cause voltage dips below the acceptable operating range of the converter loads. Unlike battery plants, converter plants rely solely upon the power supplies to clear fault protection devices. Since the DC-DC power converters are current limited, their ability to clear faults will be based upon the short burst of current from their output capacitors and the excess current available from the plant. As the technologies have taken the DC-DC power converters to higher and higher operating frequencies, their output capacitance has decreased substantially. In the past, the larger capacitors would provide a higher momentary current when a fault was introduced. In many cases, this is not enough. This paper looks at some of the considerations of converter plants with respect to fault clearing, as well as some practical approaches to resolving this problem. A Lorain 6241 converter plant was tested for its fuse clearing capabilities with and without the additional capacitor bank. The results of this testing are presented.<>