Armando C Guzman

US Patent:

20060077605, Apr 13, 2006

Filed:

Oct 8, 2004

Appl. No.:

10/961425

Inventors:

Ralph Folkers - Pullman WA, US
Jeffrey Roberts - Viola ID, US
Edmund Schweitzer - Pullman WA, US
Armando Guzman - Pullman WA, US
Gabriel Benmouyal - Longueuil, CA

International Classification:

H02H 3/24

US Classification:

361092000

Abstract:

Provided is a compensated inverse-time undervoltage load shedding system and method for use in an electrical power system. The compensated inverse-time undervoltage load shedding system includes a compensation element for determining a compensated value and an inverse-time undervoltage element operatively coupled to the compensation element and enabled based on the compensated value. When enabled, the inverse-time undervoltage element calculates a load shedding time delay value based on the compensated value, and determines a load shedding signal based on the load shedding time delay value. An associated load of the electrical power system is shed based on the load shedding signal. The compensation element may determine the compensated value using a voltage magnitude, a rate-of-change of power system voltage over time, a weighted rate-of-change of power system voltage over time, a current magnitude, a weighted current magnitude, and an impedance phasor value, to name a few.