TRANSFORMER DIFFERENTIAL PROTECTION DEVICE Russian patent published in 2024 - IPC H02H7/45 

FIELD: electrical engineering; electric power industry.

SUBSTANCE: invention relates to electrical engineering and power engineering and can be used at power plants and substations of electric power systems to ensure correct operation of transformer differential protection devices (TDP) in transient modes accompanied by saturation of magnetic conductors of current transformers (CT). Result of the claimed invention is achieved by a device for differential protection of transformers, comprising a generator of effective values of differential and braking signals, as well as instantaneous values of said signals, differential current cutoff, sensitive current element, made with possibility of comparison of effective values of the first harmonic of differential and braking signals, blocking element at external short-circuits, differential-phase and output elements. Differential-phase element is made with possibility to compare by phase of each of vectors of the first harmonic of secondary currents of current transformers, moduli of which exceed the specified value, with the vector of the first harmonic of the secondary current of the current transformer, having the greatest modulus. Output element consists of first and second logical elements AND, as well as logical element OR, wherein to the direct input of the first logical element AND the is connected the output of the sensitive current element, and the output of the blocking element is connected to the inverse input during external short-circuiting, to the direct inputs of the second logical element AND the outputs of the blocking element and the differential threshold element are connected, and to the inverse input of the second logic element AND the output of the differential-phase element is connected, wherein outputs of differential current cutoff, first and second logic elements AND are connected to inputs of logic element OR.

EFFECT: faster action of TDP at transition of external short circuit to protection coverage area.

1 cl, 3 dwg