Fault selecting method by attenuated DC component

A technology of DC component and fault line selection, applied in the direction of fault location, etc., can solve the problem of difficult fault line selection, etc., and achieve the effect of simple and practical method and intuitive theoretical basis

Inactive Publication Date: 2005-02-23
KUNMING UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, for the small ground current system where the neutral point is grounded through the arc suppression coil, when a single-phase ground fault occurs, the

Method used

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  • Fault selecting method by attenuated DC component
  • Fault selecting method by attenuated DC component
  • Fault selecting method by attenuated DC component

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Embodiment Construction

[0030] The concrete steps of this method are as follows:

[0031] (1) When the zero-sequence voltage instantaneous value u of the busbar in the small grounding current system 0 (t) greater than K u u n , The fault line selection device starts immediately, and records the zero-sequence current of each outgoing line and the zero-sequence voltage of the busbar in the 2 cycles before the fault and the 3 cycles after the fault. Among them, K u The general value is 0.35, U n Indicates the rated voltage of the busbar;

[0032] (2) Looking forward from the starting time of the line selection device, look for a voltage less than 0.01U on the zero-sequence voltage of the bus n The sampling point of , and its corresponding time is considered as the time t when the single-phase-to-ground fault occurs f ;

[0033] (3) from t f To start picking a sampling point of a cycle, use D = 1 N Σ k ...

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Abstract

A method for selecting out fault circuit in small earthing current system uses DC constituent of the first cycle after the fault to replace attenuation DC constituent for calculation and selects out fault circuit of small earthing current system with arc suppression coil based on DC constituent size. The rationale of the method is also listed in the present invention.

Description

Technical field: [0001] The invention relates to a fault line selection method using attenuated DC components, which belongs to the technical field of electric power system relay protection. Background technique: [0002] The neutral point of the distribution network is generally not grounded through the arc suppression coil or the neutral point. When a single-phase ground fault occurs, since no short circuit is formed, the regulations allow continuous operation for 1-2h, but the long-term grounding operation is very easy to form a two-phase ground fault. Grounding short circuit, arcing grounding can also cause system-wide overvoltage. In order to prevent the fault from expanding, it is necessary to signal and eliminate the fault. Therefore, it is of great significance to quickly and accurately realize fault line selection for the safe and reliable operation of distribution networks with changing operation modes and increasingly complex structures. [0003] After long-term...

Claims

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Application Information

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IPC IPC(8): G01R31/08
Inventor 束洪春司大军刘志坚邱革非董俊孙向飞唐岚梁祖权张杰
Owner KUNMING UNIV OF SCI & TECH
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