LOCALIZED APPLICATION OF HIGH IMPEDANCE FAULT ISOLATION IN MULTI-TAP ELECTRICAL POWER DISTRIBUTION SYSTEM

摘要

A high impedance fault isolation system (HIFIS) identifies, isolates anddissipateshigh impedance, low current faults which occur within an individual tap, orbranch,of an electric power distribution system using only portions of the tapaffected. Amaster meter, or father smart meter (FSM), on the affected tap sends a codedsignalto an antenna receiver combined with a microprocessor and chip which operatesanelectromagnetic control (EMC) grounding spring switch which isolates thedownedprimary conductor by causing the distribution system protecting device, i.e.,a highvoltage fuse or recloser, to de-energize the downed primary wire. Thislocalizedapplication of the HIFIS at the individual tap level allows the FSM to analyzeanddetermine, for example, that the specific field condition is a "downstreamwiredown", and that the installed isolating device has failed to operate becauseofinsufficient fault current, allowing the localized intervention of the HIFISto achievethe de-energization more efficiently and safely, and within a much shortertimeperiod. A fire door sensor circuit then receives the trip signal from themicroprocessor, causing the fire door sensor to melt open and release ashortingspring, in initiating operation of an expulsion fuse or recloser, which killsthe downedlivewire.