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Maximum current zero-sequece fault component braking method for preventing malfunction for transformer protection

A transformer protection and fault component technology, applied in the direction of emergency protection circuit devices, electrical components, etc., can solve the problem that the influence of zero-sequence current cannot be completely eliminated, and achieve the effect of preventing malfunction

Inactive Publication Date: 2008-06-11
ZHEJIANG UNIV
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Problems solved by technology

[0003] The technical problem to be solved by the present invention is aimed at Y 0 The side three-phase current conversion method cannot completely eliminate the influence of the zero-sequence current, and provides a maximum current zero-sequence fault component braking method to prevent transformer protection from malfunctioning. The transformer Y 0 The maximum value of the three-phase current fault component on the side and the zero-sequence current fault component on this side constitute a ratio brake element. When the ratio value is less than the setting value, a three-phase brake signal is output to brake the ratio differential protection of the transformer to prevent Transformer differential protection misoperation

Method used

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  • Maximum current zero-sequece fault component braking method for preventing malfunction for transformer protection

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Embodiment 1

[0010] A maximum current zero-sequence fault component braking method for preventing transformer protection maloperation, which can be realized through the circuit block diagram of a maximum current zero-sequence fault component braking component for preventing transformer protection maloperation in FIG. 1 . The element is composed of memories 1-4, subtractors 01-04, filters 11-14, maximum value circuit 21, multiplier 22 and comparator 23, wherein the input terminals of memories 1-3 and subtractors 01-04 The positive input terminals of 03 are respectively input into the transformer Y 0 side three-phase current instantaneous value signal i a i b i c , the output terminals of memories 1-3 are respectively connected to the negative input terminals of subtractors 01-03; the output terminals of subtractors 01-03 are respectively connected to the input terminals of filters 11-13, and the output terminals of filters 11-13 Connect three input terminals of the maximum value circuit ...

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Abstract

This invention discloses a brake method of the maximum current zero-sequence fault component for preventing the transformer protection misoperation, which utilizes the maximum value of three-phase current fault components at its Yo side and a said zero-sequence current fault component to make up of ratio brake elements. When the rotio value is smaller than the setting, the brake signal is output to brake the ratio differential protection. PA three-phase current brake at Yo side with supply is collected to make up of a ratio brake element using the maximum value of the fault components and the zero-sequence current fault component to avoid the misoperation of the transformer differential protection resulted in earth fault.

Description

technical field [0001] The invention relates to a power system relay protection method, in particular to a maximum current zero-sequence fault component braking method for preventing transformer protection maloperation. Background technique [0002] The existing power transformer longitudinal differential protection device uses a ratio braking element, that is, through the ratio of differential current and through current, to identify external faults and internal faults; at the same time, through inrush current and overexcitation braking elements, that is, through Analyze the waveform or harmonic content of the differential current to identify the inrush current and over-excitation current to achieve the purpose of identifying internal faults. to Y 0 / Δ wiring power transformer, in order to prevent Y 0 The zero-sequence current of the ground fault outside the side area causes the differential protection to malfunction. At present, Y 0 The method of transforming the side t...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H02H7/04
Inventor 徐习东
Owner ZHEJIANG UNIV
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