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Low-current grounding system single-phase grounding fault protection method, device and system

A single-phase ground fault and small current grounding technology, which is applied to the fault location, measuring device, measuring current/voltage, etc., can solve the problem of high misjudgment rate of the ground fault of the protection and testing device, and achieve low operation and maintenance costs and high sensitivity , a wide range of effects

Active Publication Date: 2020-07-17
NARI TECH CO LTD +3
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] In view of the above problems, the present invention proposes a single-phase ground fault protection method, device and system for a small current grounding system, which adopts a transient and steady state multi-information comprehensive judgment method, and overcomes the ground fault of decentralized single-interval protection and protection and testing devices The problem of high misjudgment rate

Method used

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  • Low-current grounding system single-phase grounding fault protection method, device and system
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  • Low-current grounding system single-phase grounding fault protection method, device and system

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Embodiment 1

[0055] Such as figure 1 As shown, an embodiment of the present invention provides a single-phase ground fault protection method for a small current grounding system, including:

[0056] Response to the signal of a ground fault;

[0057] Perform a 90° forward phase shift on the obtained bus zero-mode voltage;

[0058] For the obtained line zero-mode current and bus zero-mode voltage after phase-shifting, perform transient quantity extraction in the characteristic frequency band to obtain transient zero-mode current and transient zero-mode voltage;

[0059] Based on the obtained zero-mode current of the line, the DC component of the zero-mode current offset in the transient process is calculated;

[0060] Based on the line zero-mode current, bus zero-mode voltage, transient zero-mode current, transient zero-mode voltage, and transient process zero-mode current offset DC component, comprehensively determine whether a single-phase ground fault occurs on the line.

[0061] In a ...

Embodiment 2

[0087] Based on the same inventive concept as in Embodiment 1, the embodiment of the present invention provides a single-phase ground fault protection device for a small current grounding system, including:

[0088] a response unit for responding to a signal of an earth fault;

[0089] A phase shifting unit is used to perform a 90° forward phase shift on the obtained bus zero-mode voltage;

[0090] The feature extraction unit is used to extract the transient quantity in the characteristic frequency band from the acquired zero-mode current of the line and the zero-mode voltage of the bus bar after phase shifting, so as to obtain the transient zero-mode current and the transient zero-mode voltage;

[0091] A calculation unit, configured to calculate the DC component of the zero-mode current offset in the transient process based on the obtained zero-mode current of the line;

[0092] A judging unit for comprehensively judging and determining whether a single-phase ground fault o...

Embodiment 3

[0095] Based on the same inventive concept as in Embodiment 1, the embodiment of the present invention provides a single-phase ground fault protection system for a small current grounding system, including: a storage medium and a processor;

[0096] The storage medium is used to store instructions;

[0097] The processor is configured to operate according to the instructions to perform the steps of the method according to any one of Embodiment 1.

[0098] Those skilled in the art should understand that the embodiments of the present application may be provided as methods, systems, or computer program products. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM,...

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Abstract

The invention discloses a low-current grounding system single-phase grounding fault protection method, device and system. The method comprises the following steps: responding to a signal of a grounding fault; carrying out 90-degree forward phase shifting on an obtained zero-mode voltage of a bus; carrying out transient state quantity extraction in a characteristic frequency band on an obtained line zero-mode current and the bus zero-mode voltage after phase shift, and acquiring a transient state zero-mode current and a transient state zero-mode voltage; calculating a transient process zero-mode current offset direct-current component based on the obtained line zero-mode current; and based on the zero-mode current, the zero-mode voltage, the transient zero-mode current, the transient zero-mode voltage and the transient process zero-mode current offset direct-current component, comprehensively judging and determining whether a single-phase grounding fault occurs in the line or not. In the invention, a transient state and steady state multi-information comprehensive judgment method is adopted, and a problem of a high misjudgment rate of grounding faults of a distributed single-interval protection and protection and measurement device is solved.

Description

technical field [0001] The invention belongs to the field of relay protection for power systems, and in particular relates to a single-phase grounding fault protection method and device for a small current grounding system, in particular to a single-phase grounding fault protection method, device and device for a small current grounding system covering CT polarity discrimination. system. Background technique [0002] The neutral point grounding methods of the power system are mainly divided into two categories: the neutral point is directly grounded (large current grounding system) and the neutral point is not directly grounded (small current grounding system). The neutral point is not directly grounded, including the neutral point not grounded and the neutral point grounded through the arc suppression coil (resonance grounding). When a single-phase ground fault occurs in the system, the fault current flowing through the fault point is very small, so it is also called small ...

Claims

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Application Information

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IPC IPC(8): G01R31/08G01R31/52G01R19/00
CPCG01R31/086G01R19/00Y04S10/52
Inventor 郑玉平潘书燕余洪吴通华纪浩然龙威梁臣
Owner NARI TECH CO LTD