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1. (WO2017196224) METHOD AND DEVICE FOR FAULT CLEARING IN ELECTRIC NETWORKS WITH RING-FEED-LOOPS

Pub. No.:    WO/2017/196224    International Application No.:    PCT/SE2017/050366
Publication Date: Fri Nov 17 00:59:59 CET 2017 International Filing Date: Thu Apr 13 01:59:59 CEST 2017
IPC: H02H 7/28
H02H 9/08
Applicants: DLABORATORY SWEDEN AB
Inventors: AKKE, Magnus
Title: METHOD AND DEVICE FOR FAULT CLEARING IN ELECTRIC NETWORKS WITH RING-FEED-LOOPS
Abstract:
A method and a device for disconnection of faults in an electric network comprising a plurality of stations (14; 34; 38) connected in a loop, comprising feeding the loop from at least two feeding points(A, B) from a power source (17),earthing a neutral point of the electric network through an impedance (36),detecting earth faults in a directional earth fault protection(18) in at least one first secondary substation(14) provided with directional earth fault protection (18), disconnecting a detected earth fault by a load switching device (10) in said at least one first secondary substation (14) provided with directional earth fault protection (18),detecting fault currents arising from short circuits between two or more phases in an over-current protection (28) of a second secondary substation (34), and opening said loop with a circuit breaker (12) of said second secondary substation (34).