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Fault line selection method for single-phase-to-ground fault in middle and low voltage distribution network

A single-phase ground fault, low-voltage distribution network technology, applied in the direction of fault location, etc., can solve the problem that the fault line selection cannot be realized, and achieve the effect of rich amplitude signals, wide application range, and easy detection

Inactive Publication Date: 2006-07-12
SHANDONG DACHI ELECTRIC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

If the current transformer on the feeder is reversed, the correct fault line selection will not be realized

Method used

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  • Fault line selection method for single-phase-to-ground fault in middle and low voltage distribution network
  • Fault line selection method for single-phase-to-ground fault in middle and low voltage distribution network
  • Fault line selection method for single-phase-to-ground fault in middle and low voltage distribution network

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Embodiment Construction

[0033] The content of the present invention will be further described below according to specific embodiments. Install on-line monitoring devices by section at the grid feeder outlet or line, when a high zero-sequence voltage appears in the grid (excluding TV secondary circuit disconnection), such as 3U. > 20 ~ 30V, it can be considered that a single-phase ground fault has occurred in the power grid.

[0034] Such as figure 1 Shown in is the zero-sequence equivalent network diagram of the neutral point non-effective grounding system. The present invention realizes the medium and low voltage distribution in the form of neutral point non-grounding, arc suppressing coil grounding (resonant grounding), and high-impedance grounding through the following steps. Line selection for single-phase ground fault in power grid:

[0035] 1) Real-time detection of the zero-sequence current vector and active component of each feeder, where the zero-sequence current is the vector: i0=ia+ib+ic...

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Abstract

The invention relates to a detector for electric system fault, exactly, it is a low-voltage distribution network single-phase ground fault line choice method in a system with neutral point ungrounding and arc-suppression coil or high-resistance grounding. It can determine fault line or segment rapidly, and further automatic or manual command opposite breaker and switch operation to remove the fault line or segment. Wherein, the cosine component on projection axis of zero sequence current of all feed line is maximal and convenient to detect, limits free to the system ground way and other effect, and has wide application.

Description

technical field [0001] The invention relates to a power grid fault detection device, in particular to a single-phase ground fault line selection method of a low-voltage distribution network in a neutral point ungrounded, arc suppressing coil grounded or high-resistance grounded system. technical background [0002] Most of my country's power distribution system adopts neutral point ungrounded or arc suppressing coil grounded (resonance grounded) treatment. Single-phase ground fault is a kind of fault with a high probability of occurrence in small current grounding systems. Since the single-phase ground fault current is only the residual current after system distributed capacitance current or arc suppression coil compensation, the detection of single-phase ground fault has always been a It is a problem that is difficult to solve in relay protection, and the basis for judgment is relatively complicated. [0003] In the neutral point ungrounded power grid, a variety of line se...

Claims

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Application Information

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IPC IPC(8): G01R31/08
Inventor 陈玉国崔建江李文奎
Owner SHANDONG DACHI ELECTRIC