Patent ID: 8947837
Filing Date: 2015-02-03
Classification: H02H

Abstract:
1. An overcurrent fault protection method, comprising: detecting an overcurrent fault in a variable frequency electric power generation system (VF EPGS), the VF EPGS having a first main generator coupled to a first alternating current (AC) bus through a first generator line contactor (GLC), a second main generator coupled to a second AC bus through a second GLC and an auxiliary generator coupled to a plurality of bus tie contactors (BTCs), through a third GLC, and coupled to at least one of the first and second AC buses through the plurality of BTCs; in response to the detection of the overcurrent fault, locking out one or more of the plurality of BTCs; and in response to a continued detection of the overcurrent fault, opening at least one of the first, second and third GLCs and; locking out a first subset of the plurality of BTCs coupled between the auxiliary generator and the first AC bus in response to the auxiliary generator powering the first AC bus; opening the third GLC and shutting down the auxiliary generator in response to the continued detection of the overcurrent fault after a predetermined time delay; and locking out a second subset of the plurality of BTCs coupled between the auxiliary generator and the second AC bus.