Method for selecting fault phase of alternating current transmission line by using transient energy

Abstract

The invention relates to a method for selecting a fault phase of an alternating current transmission line by using transient energy. The method comprises the following steps of: when the alternating current transmission line fails, extracting a fault component of a three-phase current travelling wave after the fault, and constructing zero mode current and line mode current; performing wavelet transform on phase current and mode current respectively, and solving the transient energy; if the energy value of a zero mode is less than 1 percent of the maximum mode energy value, determining that the fault is a phase-to-phase fault, and otherwise, determining that the fault is an earth fault; if the energy value of a certain phase current is more than 20 percent of the maximum phase current energy value, determining that the fault is the fault phase; and if the fault is the phase-to-phase fault and the energy values of the other two-phase current are less than 20 percent of the maximum phasecurrent energy value, determining that the fault is a three-phase fault. In the method, a phase selection judgment basis is relatively simple, has relatively high applicability to transition resistance and fault initial angles, and can provide a correct basis for the tripping of a breaker in the consideration of combined reclosing at any fault initial angle.

Description

technical field [0001] The invention relates to a fault phase selection method of an AC transmission line utilizing transient energy, and belongs to the technical field of electric power system relay protection. Background technique [0002] After a fault occurs in a high-voltage AC transmission line, it is very important to select the faulty phase accurately and quickly to ensure the correct action of the relay protection device and selectively remove the faulty phase. At present, the phase selection principles widely used in protection can be divided into: traditional phase selection principles using power frequency [1] And use the phase selection principle of transient quantity. The traditional fault phase selection is mainly based on the power frequency quantity, and adopts the scheme of combining sudden quantity phase selection and steady state quantity phase selection, its performance is relatively stable, but the quick movement is limited by its own principle; Trave...

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Problems solved by technology

Using the relative relationship between mode current and phase current [4] Fault phase selection can overcome the influence of zero-mode attenuation, but the principle of traveling wave phase selection using the first wave head has the problem of low sensitivity under weak faults, and the use of transient energy can effectively solve the above problems

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