T&D World Magazine

Instrument Detects High-Impedance Faults With Arc Sense Technology

Schweitzer Engineering Laboratories, Inc. (SEL) has released high-impedance fault detection in the SEL-451 Protection, Automation, and Control System. High-impedance fault detection using patent-pending Arc Sense Technology (AST) uncovers more faults than conventional protection while maintaining system security for reliable distribution protection.

A high-impedance fault occurs when a conductor contacts a ground surface but does not produce a large fault current. The SEL-451 with AST safely detects and clears many faults that could remain undetected with conventional overcurrent elements. AST detection algorithms provide improved fault detection above traditional methods, enhanced security over existing technology, and automatic event data storage and retrieval to aid in event analysis.

Evaluate high-impedance and downed conductor events with special COMTRADE event reports dedicated to recording these events. Selectable event length from two to 40 minutes with 60 seconds of pre-fault data simplifies event analysis. Automatic event transfers to a long-term storage device ensure future events do not overwrite existing critical event information.

"Detecting downed conductors and high-impedance faults has always been problematic for utilities," said SEL Principal Research Engineer Daqing Hou. "It is now possible to enhance public safety by detecting many of these faults while still maintaining system security."

High-impedance fault detection is available now as a $1,000 option on new SEL-451 Relays or as a firmware upgrade on existing units for only $1,270.

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