Current protection method for power transmission line during single-phase high-resistance ground fault

Abstract

The invention discloses a current protection method for a power transmission line during a single-phase high-resistance ground fault. The method comprises the steps of firstly measuring an instantaneous current value at a mounting part of a current transformer of the power transmission line at each sampling instant, calculating a fundamental component, a second harmonic component, a third harmonic component and a fifth harmonic component in fault phase current of the power transmission line by processing the sampled instantaneous current values with a fourier algorithm, further calculating an amplitude of a harmonic component in the fault phase current, and then judging that the amplitude of the harmonic component in the fault phase current is greater than a product of a setting coefficient and the amplitude of the fundamental component in the fault phase current. The method realizes relay protection for the single-phase high-resistance ground fault of the power transmission line by single-end amperage, and can act correctly and reliably during the single-phase high-resistance ground fault of the power transmission line, and the acting performances are not influenced by transition resistance, a fault location and the load current.

Description

technical field [0001] The invention relates to the technical field of electric power system relay protection, in particular to a single-phase high-resistance grounding fault current protection method for transmission lines. Background technique [0002] The additional impedance generated by the transition resistance will seriously affect the action performance of the impedance distance protection. If the additional impedance generated by the transition resistance is resistive and inductive, it is easy to cause the impedance distance protection to refuse to operate when there is a fault in the protection zone of the transmission line; The distance protection action produces overtaking. [0003] High / super / extreme voltage AC transmission lines are often also heavy-duty transmission lines. Heavy-load currents will cause impedance distance protection to malfunction or refuse to operate. The impact of heavy-load current on the performance of impedance distance protection cannot...

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Problems solved by technology

[0002] The additional impedance generated by the transition resistance will seriously affect the action performance of the impedance distance protection

If the additional impedance generated by the transition resistance is resistive and inductive, it is easy to cause the impedance distance protection to refuse to operate when there is a fault in the protection zone of the transmission line; The distance protection action produces overtaking

[0003] High/super/extreme voltage AC transmission lines are often also heavy-duty transmission lines. Heavy-load currents will cause the impedance distance protection to malfunction or refuse to ...

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