Differential protection device of a power transformer
AssigneesSchneider Electric SA, Ecole Superieure d'Electricite Supelec
InventorsPatrick Bastard, Hugues Regal
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Abstract
A preprocessing circuit receives signals representative of a current circulating in a primary winding and of a current circulating in a secondary winding of a transformer. The signals representative of currents are used to calculate the values of a through current and a differential current. The preprocessing circuit performs a spectral analysis and provides a neural network with signals representative of the fundamental component of the through current, of the fundamental component of the differential current, of the second harmonic and of the fifth harmonic of the differential current. The neural network identifies fault conditions and normal operation states, and supplies a triggering and/or alarm signal to an output when a fault condition is detected.
Claims5
A differential protection device of a power transformer comprising first measuring means for measuring the current flowing in a primary winding of the transformer, second measuring means for measuring the current flowing in a secondary winding of the transformer, interrupting means connected to the primary winding of the transformer to interrupt the electrical power supply of the transformer and a processing circuit connected to the first and second measuring means, supplying a tripping signal to the interrupting means and/or information signals to annunciation or monitoring means, the processing circuit comprising sampling means connected to the first and second measuring means to sample signals representative of the currents measured in the primary and secondary windings, the processing circuit further comprising pre-processing means connected to the sampling means and a neuron network comprising inputs connected to the pre-processing means and at least one output to supply the tripping and/or information signals, the pre-processing means supplying to the neuron network signals representative of the fundamental component, of the second harmonic and of the fifth harmonic of a differential current and a signal representative of a through-current.
Dependencies are inferred from the claim text.