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Transformer longitudinal error protective method with multiple side zero sequence ratio brake

A technology of zero-sequence current and ratio braking, applied in emergency protection circuit devices, electrical components, etc., can solve the problem that zero-sequence current cannot be completely eliminated, and achieve the effect of avoiding inconsistencies in errors

Active Publication Date: 2008-02-06
ZHEJIANG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] 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 transformer differential protection method with multi-side zero-sequence current ratio braking is provided. The weighted summation value of the zero-sequence current on the grounding side (or branch) of the neutral point is weighted and summed to form the braking current containing the zero-sequence current, which is composed of the braking current containing the zero-sequence current and the differential current of the corresponding phase This phase ratio braking element, when the differential current is greater than the braking current including zero-sequence current and greater than the minimum operating current, output the action signal of the phase ratio braking element

Method used

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  • Transformer longitudinal error protective method with multiple side zero sequence ratio brake
  • Transformer longitudinal error protective method with multiple side zero sequence ratio brake
  • Transformer longitudinal error protective method with multiple side zero sequence ratio brake

Examples

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Embodiment 1

[0016] A transformer longitudinal differential protection method with multi-side zero-sequence current ratio braking, which can be realized through the circuit block diagram of a transformer longitudinal differential protection ratio braking component with multi-side zero-sequence current ratio braking in Figure 3 . This element consists of a multiplier A 1 , B 1 、C 1 , M 1 , 01, 02, 03, Adder A 3 , B 3 、C 3 , M 0 , and Comparator A 4 , B 4 、C 4 constitute. where multiplier A 1 , B 1 、C 1 One of the input terminals of the transformer differential protection respectively inputs the filtered three-phase braking current signal I representing the through current za , I zb , I zc , and its other input end enters the ratio brake coefficient K Z =0.4; one input terminal of the multiplier 01, 02, 03 respectively inputs the filtered zero-sequence current signal 3I of each neutral point grounding side (or branch) of the transformer 10 , 3I 20 , 3I 30 , and the other ...

Embodiment 2

[0018]A transformer longitudinal differential protection method with multi-side zero-sequence current ratio braking, which can be obtained through the circuit block diagram of another transformer longitudinal differential protection ratio braking component with multi-side zero-sequence current ratio braking in Figure 4 accomplish. This element consists of the subtractor A 11 , B 12 、C 13 , Multiplier A 21 , B 22 、C 23 , 011, 021, 031, M 4 , Adder A 31 , B 32 、C 33 、A 41 , B 42 、C 43 , M 3 and comparator A 51 , B 52 、C 53 constitute. where the subtractor A 11 , B 12 、C 13 The positive input terminals of the transformer respectively input the filtered braking current signal I representing the through current of the transformer differential protection za , I zb , I zc , and the negative input terminal respectively inputs the brake inflection point current value I in the longitudinal differential protection of the transformer reso =1.2×I n , I n is the tra...

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Abstract

This invention discloses a longitudinal deviation protection method for a transformer with multi-side zero sequence rate brake, which utilizes the weight sum values of the brake current representing the through current in the longitudinal difference protection and the zero sequence currents of the earth side of the neutral points to be weighted and summed to get the brake current containing zero sequence current, which is used to make up of the phase rate brake element with the related phase differential current, when the differential current is greater than brake current containing the zero sequence current and the smallest action , the action signal of said phase rate brake element is output.

Description

technical field [0001] The invention relates to a relay protection method of a power system, in particular to a transformer longitudinal differential protection method with multi-side zero-sequence current ratio braking. Background technique [0002] The current longitudinal differential protection of power transformers consists of components such as differential quick-break, ratio differential, excitation inrush current detection, and over-excitation detection. According to DL / T 684-1999 "Large Generator Transformer Relay Protection Setting Calculation Guidelines", the block diagram of transformer longitudinal differential protection is shown in Figure 1, and the principle wiring example of longitudinal differential protection is shown in Figure 2. Usually using a current transformer for Y 0 Y / Δ transformation is performed on the three-phase current on the side to eliminate the influence of zero-sequence current. Obviously, after the transformation, each current does not ...

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
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