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US 4,398,255 AGranted
Polyphase angle estimator
AssigneeGeneral Electric Company
InventorWilliam J. Premerlani
Life of this patent
Estimating the term…
Abstract
A high speed relay for detecting multiphase faults using operating and polarizing signals from static transmission line protective relays provides an instantaneous estimate of the relative phase angle between relay signals without any loss of relay security.
Claims4
A power system relay for rapidly detecting multiphase faults in transmission lines comprising:
- means having an input of the multiphase voltage and currents of said transmission line for generating a polarizing signal and an operating signal for each input phase;
- a first summing means;
- means for multiplying the polarizing signal relating to one phase by the operating signal relating to the same phase and coupling the result for each phase to a different positive input of said summing means;
- means for generating a signal indicative of the average amplitude of all said polarizing signals;
- means for generating a signal indicative of the average amplitude of all said operating signals;
- and
- means for multiplying said average polarizing signals and said average operating signals together and adjusting the product by a predetermined gain, said gain determining the balance angle between phases, said adjusted product being coupled to a negative input of said summing means,
- said summing means output indicating an abnormal condition when it is above a predetermined value.
5 more elements
Dependencies are inferred from the claim text.