Variable split-phase zero sequence fault component braking method for preventing transformer protection from malfunction

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: 2005-05-11
ZHEJIANG UNIV
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  • Claims
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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 zero-sequence current, and a method of transforming phase-separated zero-sequence fault component braking to prevent transformer protection maloperation is provided, using a transformer Y that removes zero-sequence components 0 The three-phase current fault component on the side and the zero-sequence current fault component 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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  • Variable split-phase zero sequence fault component braking method for preventing transformer protection from malfunction
  • Variable split-phase zero sequence fault component braking method for preventing transformer protection from malfunction
  • Variable split-phase zero sequence fault component braking method for preventing transformer protection from malfunction

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Embodiment 1

[0013] A braking method for transforming phase-separated zero-sequence fault components to prevent maloperation of transformer differential protection. accomplish. This element is composed of memories 1-4, subtracters 01-04, 11-13, multipliers 21, 22, filters 31-34 and comparators 41-43. Among them, the input terminals of the memory 1~3 and the positive input terminals of the subtractors 01~03 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 memory 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 positive input terminals of subtractors 11-13; the input terminals of memory 4 and The positive input terminals of the subtractor 04 are respectively input into the transformer Y 0 side zero-sequence current instantaneous value signal 3i o , the output terminal of the memory device...

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Abstract

The failure component of three-phase current at Y0 side of transformer, in which the zero sequence failure components are removed, and the zero sequence current failure component are used to build up the rate break component. When the rate value is less than setting value, the break signal is outputted to break the rate differential protection of relating transformer. The invention can avoid miss -protection caused by ground fault of Y0 side when error of three-phase current transformer is disagreeing.

Description

technical field [0001] The invention relates to a method for relay protection of a power system, in particular to a braking method for transforming 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 ...

Claims

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Application Information

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