Power distribution network single-phase disconnection fault protection method and system thereof

A technology of disconnection fault and distribution network, applied in the field of single-phase disconnection fault protection method and system field of distribution network, can solve the problems of single-phase disconnection and non-grounding of distribution network, so as to avoid false start and reduce frequent calculation Burden, the effect of avoiding electric shock to humans and animals

CN113848429APending Publication Date: 2021-12-28STATE GRID SHAANXI ELECTRIC POWER RES INST +1
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Patent Information

Authority / Receiving Office
CN · China
Current Assignee / Owner
Publication Date
2021-12-28

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Abstract

The invention discloses a power distribution network single-phase disconnection fault protection method and a system thereof. The method comprises the following steps: acquiring three-phase current of each outgoing line of a transformer substation; extracting a fundamental wave vector of the three-phase current by using FFT; calculating the break variable of the three-phase current amplitude by using the fundamental wave vector; if the break variables of the three-phase current amplitudes are all smaller than 0, starting protection; after protection is started, sequencing the absolute values of the three-phase current amplitude break variables, and respectively calculating the ratio lambda of the maximum phase of the absolute values of the three-phase current amplitude break variables to the load current before the fault and the phase difference beta of the minimum absolute values of the break variables and the intermediate phase current; and judging whether the line has a broken line high-resistance fault or not according to lambda and beta, when conditions are met, determining that the fault occurs in the line, otherwise, determining that the fault does not occur in the line, and when it is determined that the fault occurs in the line, performing fault protection. The method can be fused with in-station current protection to realize quick isolation of a broken line fault, and the broken line fault can be isolated in a minimum range through a time range matching method.
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Description

technical field

[0001] The invention belongs to the technical field of relay protection, and in particular relates to a single-phase disconnection fault protection method and system of a distribution network. Background technique

[0002] At present, the overhead lines of my country's distribution network are basically insulated, causing lightning strikes and disconnection faults to occur from time to time. Overvoltage, motor damage, personal injury and other accidents will occur after disconnection fault, so it has attracted people's attention in recent years.

[0003] At present, the treatment of disconnection faults mainly includes centralized line selection in the station, and section positioning and isolation based on feeder automation technology outside the station. Line selection in the station is generally realized by positive sequence current mutation or negative sequence current, while the current ground fault The line selection device mainly uses zero-sequence vo...

Examples

Embodiment Construction

[0048] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some of the embodiments of the present invention, but not all of them. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

[0049] In the description of the present invention, it should be understood that the terms "comprising" and "comprising" indicate the presence of described features, integers, steps, operations, elements and / or components, but do not exclude one or more other features, Presence or addition of wholes, steps, operations, elements, components and / or collections thereof.

[0050]It should also be understood that the terminology used in the description...