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Transformer longitudinal error protecting method with maximum side zero sequence ratio brake

A zero-sequence current and ratio braking technology, applied in emergency protection circuit devices, electrical components, etc., can solve the problem of not being able to completely eliminate zero-sequence current, 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 longitudinal differential protection method with maximum zero-sequence current ratio braking is provided. The maximum value of the zero-sequence current on the neutral point grounding side (or branch) is weighted and summed to form the braking current containing zero-sequence current, and the braking current containing zero-sequence current and the differential current of the corresponding phase are used to form 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 ratio braking element

Method used

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  • Transformer longitudinal error protecting method with maximum side zero sequence ratio brake
  • Transformer longitudinal error protecting method with maximum side zero sequence ratio brake
  • Transformer longitudinal error protecting method with maximum side zero sequence ratio brake

Examples

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Embodiment 1

[0016] A transformer longitudinal differential protection method with maximum zero-sequence current ratio braking, which can be realized through the circuit block diagram of a transformer longitudinal differential protection component with maximum zero-sequence current ratio braking in Fig. 3 . The element is composed of the maximum value circuit 01, the multiplier A 1 , B 1 、C 1 , 02, adder A 3 , B 3 、C 3 and comparator A 4 , B 4 、C 4 constitute. Among them, the input terminals of the maximum value circuit 01 respectively input the filtered zero-sequence current signal 3I of each neutral point grounding side (or branch) of the transformer 10 , 3I 20 , 3I 30 , whose output terminal is connected to one input terminal of the multiplier 02; the other input terminal of the multiplier 02 inputs the zero-sequence braking coefficient K 0 =0.15, the output terminals are respectively connected to the adder A 3 , B 3 、C 3 One input of the multiplier A 1 , B 1 、C 1 One o...

Embodiment 2

[0018] A transformer longitudinal differential protection method with maximum zero-sequence current ratio braking, which can be realized through the circuit block diagram of another transformer longitudinal differential protection element with maximum zero-sequence current ratio braking shown in Fig. 4 . The element consists of the maximum value circuit 03, the subtractor A 11 , B 12 、C 13 , Multiplier A 21 , B 22 、C 23 , 04, adder A 31 , B 32 、C 33 、A 41 , B 42 、C 43 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 protectionza , 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 =1.1×I n , I n is the transformer rated current con...

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Abstract

This invention discloses a longitudinal deviation protection method for a transformer with the largest side zero sequence rate brake, which weights a brake current representing through current in the longitudinal difference protection and the maximum value in the zero sequence current of the earth side of the neutral points in the transformer and sums to get a brake current with zero sequence current, which is used to get the phase rate brake element with the differential current of a related phase, when the differential current is greater than the brake current with the zero sequence current and the smallest action current, the action signal of the rate brake element of said phase 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 maximum 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 con...

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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