Transformer winding turn-to-turn short circuit protection method and device and storage medium

Abstract

The invention discloses a transformer winding turn-to-turn short circuit protection method and device and a storage medium. The method comprises the steps of obtaining the currents at the high-voltage, medium-voltage and low-voltage sides of three phases of a transformer at a first sampling moment, and obtaining a first differential current through calculation; obtaining the currents at the high-voltage, medium-voltage and low-voltage sides of three phases of the transformer at a second sampling moment, and obtaining a second differential current through calculation; obtaining a differential current increment according to the first differential current and the second differential current; calculating the current increments at the high-voltage side, the medium-voltage side and the low-voltage side of each phase, and judging whether the differential current increment is not less than the maximum value of the absolute values of the current increments at the three sides or not; if so, solving a positive sequence component and a negative sequence component according to the differential current increment; and when the positive sequence component is equal to the negative sequence component, judging whether the CT disconnection protection, CT saturation protection and excitation surge current protection of the transformer are started or not, and if not, starting the differential protection. According to the invention, the sensitivity and reliability of differential protection can be effectively improved.

Description

technical field [0001] The invention relates to the technical field of power equipment operation management, in particular to a protection method, device and storage medium for transformer winding inter-turn short circuit. Background technique [0002] At present, the protection method for internal inter-turn short circuit faults of transformers is usually differential protection, but in actual operation, when a slight inter-turn short circuit occurs in the transformer, differential protection cannot play an effective protective role, and the sensitivity is not high. In addition, for YyD11 transformers commonly used in power systems, when a single-phase-to-ground fault occurs in the outgoing line of the low-voltage delta-connected winding, if the fault point is between the current transformer and the outgoing line of the low-voltage bushing, the differential protection will not operate. The safe operation of the transformer has a great impact. Contents of the invention ...

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Problems solved by technology

[0002] At present, the protection method for internal inter-turn short circuit faults of transformers is usually differential protection, but in actual operation, when a slight inter-turn short circuit occurs in the transformer, differential protection cannot play an effective protective role, and the sensitivity is not high

In addition, for YyD11 transformers commonly used in power systems, when a single-phase-to-ground fault occurs in the outgoing line of the low-voltage delta-connected winding, if the fault point is between the current transformer and the outgoing line of the low-voltage bushing, the differential protection will not operate. The safe operation of transformers has a greater impact

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