Power distribution network fault line selection method based on dominant frequency zero sequence power

Abstract

The invention discloses a power distribution network fault line selection method based on dominant frequency zero sequence power, aiming to solve the problem that when a complex small current grounding system generates a single-phase earth fault, present line selection methods based on dependency may cause misjudgment due to insufficient criterion margin. In order to solve the problem of insufficient criterion margin, the invention provides a power distribution network fault line selection method based on dominant frequency zero sequence power, which selects lines by employing dominant frequency zero sequence power as characteristic quantity, and calculates the dominant frequency zero sequence power integrated correlation coefficient corresponding to each feeder line, wherein a fault line integrated correlation coefficient is less than zero, and a perfect line integrated correlation coefficient is greater than zero. A lot of simulation results show that the method increases line selection criterion margin and line selection accuracy, and is not influenced by switching angles and fault resistors.

Description

technical field [0001] The invention belongs to the technical field of distribution network fault line selection methods, and in particular relates to a distribution network fault line selection method based on primary frequency zero-sequence power. Background technique [0002] The distribution network structure is complex, and the existing fault line selection methods are still limited. For example, the signal injection method can use the signal detection device to judge the faulty line, but it needs to install signal injection equipment, the investment is relatively large, and it is affected by intermittent arcs and fault resistance; the zero-sequence admittance method uses the admittance of each line before and after the fault The change of the coefficient can be used to select the fault line, but it needs to be used together with the arc suppressing coil, and the scope of application is limited; the first half-wave method uses the principle that the polarity of the firs...

AI Technical Summary

Problems solved by technology

[0002] The structure of the distribution network is complex, and the existing fault line selection methods are still limited

For example, the signal injection method can use the signal detection device to judge the faulty line, but it needs to install signal injection equipment, the investment is relatively large, and it is affected by intermittent arcs and fault resistance; the zero-sequence admittance method uses the admittance of each line before and after the fault The change of the coefficient can be used to select the fault line, but it needs to be used together with the arc suppressing coil, and the scope of application is limited; the first half-wave method uses the principle that the polarity of the first wave head of the fault line is opposite to that of the healthy line to select the line, but it is too demanding for the acquisition equipment. High; the zero-sequence current correlation analysis method can use the principle that the comprehensive correlation of the zero-sequence current of the faulty line is small and the comprehensive correlation of the sound line is large, but the margin of the criterion is sometimes too low, which is easy to cause misjudgment

The correlative line selection method based on wavelet packet proposed in relevant literature needs to be improved due to the problem of wavelet basis function selection

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