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Multi-lateral current magnitude voltage magnitude based transformer relay protecting method

A relay protection and relay protection device technology, applied in the direction of emergency protection circuit devices, electrical components, etc., can solve the problems of difficulty and complexity in accurately judging the inrush current, and achieve the effect of high sensitivity and good reliability

Inactive Publication Date: 2010-06-30
SHANDONG UNIV
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Problems solved by technology

However, both transformer faults and inrush currents are dynamic processes, especially when faults and inrush currents exist at the same time or occur successively, the situation is more complicated, which brings great difficulties to the accurate judgment of inrush currents

Method used

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  • Multi-lateral current magnitude voltage magnitude based transformer relay protecting method
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  • Multi-lateral current magnitude voltage magnitude based transformer relay protecting method

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Embodiment 2

[0052] For multi-coil transformers, since the short-circuit impedance between two windings can be obtained through experiments, the voltage on both sides can be selected according to the application, and the current on all sides can be used to calculate the differential current, and then the branch impedance can be calculated in the same way as above, and The internal fault is judged by the size and characteristics of the branch impedance. Attached below Figure 4 An embodiment of a multi-winding transformer will be described.

[0053] Figure 4 In this paper, a three-phase two-winding transformer is taken as an example. The three sides of the transformer are H side, L side and M side respectively, and the phasor calculation and judgment of the branch impedance of phase A is taken as an example. Assuming that the current transformer TA and the voltage transformer TV are used to measure, calculate and other methods, the current and voltage of the three-phase winding on the H ...

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Abstract

The invention provides a multi-lateral current magnitude voltage magnitude based transformer relay protecting method, which has the advantages of convenience, reliability, sensitivity and the like. The method comprises the following steps that: 1) a relay protection device acquires sampling values of three-phase voltage and current on each side of the transformer, and calculates out the current magnitude and the voltage magnitude on each side of each phase of winding; 2) the relay protection device calculates the branch impedance of each phase of the winding according to the current magnitude and the voltage magnitude; and 3) a +R axis area is set on an impedance plane as an action area, and failure inside the transformer is determined when the branch impedance drops in the region more than the set time.

Description

Technical field: [0001] The invention relates to the field of relay protection, in particular to a transformer relay protection method based on multi-side current and voltage quantities. Background technique: [0002] As the main protection for transformer internal faults, longitudinal current differential protection has been widely used for a long time. However, Kirchhoff's current law, which is the basic principle of differential protection, is only an approximation when applied to the protection of windings on different sides of the transformer. Therefore, the transformer longitudinal current differential protection has always been troubled by the problem of inrush current. In order to distinguish the inrush current of transformer from the internal fault current, various criteria of inrush current have been proposed. These criteria can be roughly divided into two categories, one is to judge only by the amount of current, and the other is to judge by combining the amount ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02H7/045
Inventor 刘世明贠志皓邹贵彬王慧肖洪
Owner SHANDONG UNIV
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