Fault line selection method based on transient current projection component projection coefficient comparison

Abstract

The invention discloses a fault line selection method based on transient current projection component projection coefficient comparison. When the busbar zero-sequence voltage amplitude exceeds a constant value, zero-sequence current of each feeder outlet of a power distribution network is acquired, transient components of the zero-sequence current of each feeder outlet and busbar zero-sequence voltage are extracted, then transient zero-sequence current of each feeder outlet is projected on the busbar transient zero-sequence voltage, finally, fault lines are judged according to projection coefficients of projection components, and a feeder with the largest projection coefficient is selected as a fault feeder. The method solves the problem about line selection for high resistance ground faults in small current ground systems and has high actual application value.

Description

technical field [0001] The invention relates to the technical field of distribution network fault detection, in particular to a fault line selection method based on comparison of projection coefficients of transient current projection components. Background technique [0002] Since the medium-voltage distribution network directly faces users, and single-phase grounding accounts for about 80% of the total distribution network faults, the reliable detection of single-phase grounding faults has a significant impact on power supply reliability. In China and continental Europe, most of the medium-voltage distribution network adopts the grounding method of the arc suppression coil, which is the so-called resonant grounding system. When a single-phase ground fault occurs, it is not necessary to remove the fault immediately, which is conducive to improving the reliability of power supply. However, due to the weak fault current and other reasons, it is difficult to identify the groun...

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Problems solved by technology

The main difficulty of this method is that the line selection device needs to be connected to the three-phase current signal and is greatly affected by TV / TA transmission errors (such as unbalance)

[0005] For small current grounding systems, the power frequency current itself has no obvious fault characteristics and cannot be directly used for fault detection (the active component of power frequency current is theoretically feasible, but the content is small and easily affected by TV / TA transmission characteristics, and there are great difficulties in practical use ), other technical solutions must be sought

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