Honeywell International Inc.

Sanjay Kumar Chaudhary

Zhenning Liu

David Lazarovich

Ileana Rusan

Srinivasa Rao Dangeti

Prashant Purushotham Prabhu K

Subodh Keshri

A coordinated arc fault protection scheme in a hierarchical power distribution system is disclosed. The methods according to embodiments of the present invention may be considered an 'event and time graded' analysis. In event and time based analysis, the number of confirmed arc signature may be monitored with respect to time in the main feeder line as well as the branched feeders. The confirmed arc signature in the branched feeder, as well as in the main feeder, may be captured and time stamped. A trip command may be issued first in the intended branched feeder if the branched feeder experiences a minimum number of events within a given time. During the same time period, the main feeder also monitors similar arcing events. If the tripping of the branched feeder occurs and the main feeder still detects arcing events, the main feeder may be tripped after a certain period of time or a certain number of confirmed arc signature. If there is no arc in the branched feeder and the main feeder itself experiences the arc, then the main feeder may be tripped after a predetermined period of time so that the current to all the branched feeders may be cut and the main feeder may be protected.

Method of ensuring the coordinated arc fault protection in a heirarchial power distribution system

Methods for detecting wet arc faults are based on the direct current (DC) signature analysis and pattern matching pertaining to wet arc characteristics. While magnifying some wet arc fault signatures, it may be found that the wet arc current signal itself resembles a normal current signal in both time and frequency domains. The change in magnitude or high frequency behavior found may not be enough to distinguish a wet arc fault signature from a normal signature. Embodiments of the present invention may look at the magnitude change in the DC content per cycle of the wet arc current signal, which may be more positive in one cycle while, in the next cycle, it may be negative in a relative manner. A particular number of these changes may be determinative of a wet arc fault.

Method of detecting the wet arc fault in the AC power distribution applications

An ungrounded electrical power distribution system may experience a single line to ground fault. Such a fault may not disrupt operation of the system, but its presence may raise a risk of additional problems if left uncorrected. A system for progressively grounding the ungrounded system may be initiated when a line to ground fault is suspected. As grounding through successively lower impedance proceeds, fault current may increase and detection of severity of the line to ground fault may be more readily achieved, thus facilitating localization of the fault.

Ground fault detection in an ungrounded electrical system

An ungrounded or floating DC electrical power distribution system may experience a single line to ground fault. Such a fault may not disrupt operation of the system, but its presence may raise a risk of additional problems if left uncorrected. A system for progressively grounding the ungrounded system may be initiated when a line to ground fault is suspected based on the voltage difference measured to a common chassis point. As grounding through successively lower impedance proceeds, fault current may increase and detection of severity of the line to ground fault may be more readily achieved, thus facilitating localization of the fault. Localization may be achieved through an analysis of direction of capacitive currents in isolatable zones of the system.

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Aalborg, Denmark

Sanjay Kumar Chaudhary