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Split-phase zero-sequence fault component braking method for preventing malfunction for transformer protection

A technology for transformer protection and fault components, applied in 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 misoperation

Inactive Publication Date: 2007-11-21
ZHEJIANG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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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 a method for braking the phase-separated zero-sequence fault component to prevent transformer protection from malfunctioning is provided. The transformer Y 0 The sudden change of the three-phase current on the side and the sudden change of the zero-sequence current on this side respectively form a ratio braking element. When the ratio value is less than the setting value, the braking signal of the corresponding phase is output to brake the ratio differential protection of the transformer to prevent the transformer from Differential protection misoperation

Method used

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  • Split-phase zero-sequence fault component braking method for preventing malfunction for transformer protection

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Embodiment 1

[0012] A phase-separated zero-sequence fault component braking method for preventing transformer protection maloperation, which can be realized through the circuit block diagram of a phase-separated 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, multipliers 21, comparators 31~33, in which the input terminals of memories 1~3 and the positive inputs of subtractors 01~03 The terminals are respectively input into the transformer Y 0 Side three-phase current instantaneous value signal i a i b i c ; The negative input terminals of the subtractors 01-03 are respectively connected with the output terminals of the memory devices 1-3, and the output terminals are respectively connected with the input terminals of the filters 11-13; the output terminals of the filters 11-13 are respectively connected with the comparator 31 The positive input end of...

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Abstract

This invention discloses a phase-splitting zero-sequence fault component brake method for preventing transformer protection misoperation, which makes up of three-ratio brake elements by abrupt volumes of the three-phase current and zero-sequence current at Yo side, when ratio value is smaller than the setting, the relevant intebraked signal is output to brake the relevant phase ratio differential protection to prevent translay protection misoperation of the transformer. Only active Yo side three-phase current and said side zero-sequence current are collected to make up of ratio brake elements with their fault components to avoid the differencial protection misoperation of transformers.

Description

technical field [0001] The invention relates to a method for relay protection of a power system, in particular to a braking method for phase-separated zero-sequence fault components to prevent maloperation of transformer protection 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 transformin...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H02H7/045
Inventor 徐习东
Owner ZHEJIANG UNIV