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Method of detecting triphase asymmetry failure in low voltage line and comprehensive protection module

A low-voltage line, fault detection technology, applied in the fault location, emergency protection circuit device, emergency protection device with automatic disconnection, etc. The effect of simplified protection, wide application range and easy operation and maintenance

Inactive Publication Date: 2007-10-03
傅桂兴
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, these line selection methods and devices are only used for medium and low-voltage power grids where the neutral point is not grounded or the neutral point is grounded through the arc suppression coil (or zero-sequence reactor). They are only used for single-phase ground leakage fault detection and selective protection. It is used for the detection and protection of open-phase fault and two-phase short-circuit fault

Method used

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  • Method of detecting triphase asymmetry failure in low voltage line and comprehensive protection module
  • Method of detecting triphase asymmetry failure in low voltage line and comprehensive protection module
  • Method of detecting triphase asymmetry failure in low voltage line and comprehensive protection module

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Embodiment Construction

[0024] Now in conjunction with Fig. 1, the setting situation of the timing discrimination rule of arbitrary two-phase quantities in the method of the present invention is illustrated, the waveform timing relationship of JZ shown in a and b among the figures and CJ conforms to this rule, and JZ shown in c, d, e The waveform timing relationship with CJ does not comply with this rule.

[0025] The basic principle of the two-phase sequence identification circuit is illustrated in conjunction with Fig. 2. It is composed of two D flip-flops DC1, DC2, two NOT gates F1, F2, a two-NAND gate YF, an R-S latch RS and a Composed of frequency division and time-limiting circuits. In Figure 2, the phasor JZ is connected to the D input terminal of DC1, and after JZ is inverted, it is connected to the D input terminal of DC2; the phasor CJ is connected to the clock input terminal of DC1, and after CJ is inverted, it is connected to the clock input terminal of DC2; The frequency division and ti...

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Abstract

The method of detecting triphase asymmetry failure in low voltage line includes zero sequence current time sequence identification and interphase time sequence identification. The comprehensive protection module for triphase asymmetry failure in low voltage line includes one zero sequence voltage signal processing circuit, one zero sequence current signal processing circuit, one asymmetry failure time sequence discriminator, one triphase voltage signal processing circuit and one triphase current signal processing circuit. The present invention can search failed line in 380 V and 660 V power network in high sensitivity and high accuracy, and realize the detection on and protection against phase failure and interphase short circuit.

Description

technical field [0001] The invention belongs to a power system fault detection and relay protection device, in particular to the identification and protection of three asymmetrical faults of a low-voltage line, such as single-phase ground leakage or short circuit, single-phase disconnection (phase loss operation) and two-phase short circuit. Background technique [0002] The neutral point of the low-voltage (380V or 660V) power grid in industrial and mining enterprises can be directly grounded or ungrounded. For example, the underground low-voltage power grid in coal mines adopts the neutral point ungrounded mode, while the ground low-voltage power grid of general industrial and mining enterprises and rural power grids mostly adopts the three-phase four-wire system in which the neutral point is directly grounded. On the one hand, this three-phase four-wire low-voltage power grid is responsible for the power supply of many three-phase power loads of low-voltage asynchronous m...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01R31/08H02H3/26
Inventor 傅桂兴付英
Owner 傅桂兴
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