Loading patent…
AssigneeAsea Brown Boveri AG
InventorsLeif Eriksson, Murari M. Saha
Estimating the term…
A method and a device, after a fault has occurred in a power network, for measuring and recreating the phase currents I.sub.B prior to the occurrence of the fault by determining continuously, starting from sampled measured values of the phase currents up to the time of the fault for each phase, the amplitude I and the phase angle .phi. of the phase currents based on two consecutive sampled measured values, whereupon a comparison is made between the last determined value I.sub.k obtained and the rated current I.sub.n of the power network. If I.sub.k is greater than I.sub.n, it is considered that a fault has occurred and the phase currents prior to the fault are indicated as I.sub.B =I.sub.k-1 .multidot.sin (.phi..sub.k-1 +.omega.(t-t.sub.k-1)).
A method, after the occurrence of a fault in a power network, of measuring and recreating the phase currents (I.sub.B) prior to the occurrence of the fault, comprising the steps of:
A device for recreating the phase currents (I.sub.B) in a power network prior to the occurrence of a fault, having access to sampled values of the present phase current I.sub.A, for each phase comprising:
Dependencies are inferred from the claim text.