US 12,107,414 B2
Systems and methods for operating an islanded distribution substation using inverter power generation
Scott M. Manson, Moscow, ID (US); Jorge Fernando Calero, Coral Springs, FL (US); and Angelos Kokkinis, Collinsville, IL (US)
Assigned to Schweitzer Engineering Laboratories, Inc., Pullman, WA (US)
Filed by Schweitzer Engineering Laboratories, Inc., Pullman, WA (US)
Filed on Jun. 10, 2022, as Appl. No. 17/806,318.
Claims priority of provisional application 63/239,691, filed on Sep. 1, 2021.
Prior Publication US 2023/0069168 A1, Mar. 2, 2023
Int. Cl. H02H 7/22 (2006.01); H02H 1/00 (2006.01)
CPC H02H 7/22 (2013.01) [H02H 1/0007 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A fault current detector configured to:
operate in a first mode when a bulk electric system is providing electric power to a first load of an electrical delivery system using a first operating frequency, wherein the fault current detector is configured to disconnect the first load from the bulk electric system in response to determining that the first operating frequency droops below a first frequency threshold; and
operate in a second mode when an inverter is providing the electric power to the first load using a second operating frequency higher than the first operating frequency, wherein the fault current detector is configured to disconnect the first load from the inverter in response to determining that the second operating frequency droops below a second frequency threshold.