Small current system grounding fault positioning method

Abstract

The invention discloses a small current system grounding fault positioning method. The method includes the following steps: extracting the zero sequence currents prior to and after the moment of a fault of each feeder terminal on a faulty feeder; moving a data window point by point and calculating the feature value of zero sequence current of respective feeder terminal under each data window; establishing a feature value curve for each feeder terminal; acquiring the sampling point corresponding to the maximum feature value of each feature value curve of the feeder terminal which is closest tothe bus on the faulty feeder; acquiring the feature values that correspond to the same sampling points that are acquired from the feature value curves of the rest of the feeder terminals; calculatingthe Euclidean distance of the feature values of the adjacent two feeder terminals; ranking the Euclidean distances from long to short and selecting N biggest Euclidean distances; if one Euclidean distance is greater than the sum of the rest of the N-1 Euclidean distances, taking the interval between two feeder terminals that correspond to the Euclidean distance as a fault interval. According to the invention, the method herein can increase reliability of fault positioning and reduce communication pressure of data channels.

Description

technical field [0001] The invention relates to the technical field of distribution network fault detection, in particular to a method for locating ground faults in small current systems. Background technique [0002] In our country, the distribution network area is widely distributed, the failure rate is high, and the protection configuration is relatively low. The medium-voltage distribution network is dominated by overhead lines, and the proportion of single-phase ground faults is large. Since the distribution network generally adopts the low-current grounding method, no short-circuit loop is formed when a single-phase ground fault occurs, and only a small fault is generated by the zero-sequence capacitance of the feeder. fault current, so that the system can still continue to run with faults for 1 to 2 hours. In order to avoid further expansion of the single-phase ground fault, it is necessary to find the ground fault point as soon as possible and eliminate the fault. ...

AI Technical Summary

Problems solved by technology

[0005] In view of the defects of low positioning reliability and large amount of data uploaded in the existing small current fault location method, it is necessary to provide a small current system ground fault location method, which reduces the amount of data uploaded and the communication pressure of the data channel and improve positioning reliability

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