Power distribution network grounding fault protection method based on fuzzy measurement fusion criteria

Abstract

The invention discloses a power distribution network grounding fault protection method based on fuzzy measurement fusion criteria. The method comprises the following steps: acquiring a plurality of fault characteristic quantities of a protected feeder line to form a historical sample, and acquiring a sample to be tested according to the same method; clustering and dividing n historical samples into a fault class and a non-fault class by adopting a clustering algorithm; respectively taking membership degree, distance specific gravity measurement and angle specific gravity measurement as similarity measurement criteria, calculating a fault measurement value and a non-fault measurement value of the sample to be tested, and constructing a fuzzy measurement fusion criterion matrix of the sampleto be tested; and taking the fuzzy measurement fusion criterion matrix as a judgment set of a judgment index system, constructing a factor set of the judgment index system by using all similarity metric criteria, presetting the weight coefficient of each element in the factor set, and judging the fuzzy measurement fusion criterion matrix to obtain whether the distribution network to be tested isin fault or not. According to the method, the fault judgment interval is broadened, erroneous judgment caused by factors such as power system oscillation is effectively avoided, and the robustness isimproved.

Description

technical field [0001] The invention relates to the technical field of power systems, in particular to a distribution network grounding fault protection method based on fuzzy metric fusion criteria. Background technique [0002] my country's 6-66kV medium-voltage distribution network generally adopts the neutral point ungrounded and arc suppression coil grounded methods. When a single-phase ground fault occurs, the line voltage of the system remains symmetrical, so the continuous power supply to the load is not affected, and the system can still continue to run for 1 to 2 hours. However, especially for small current grounding systems, due to low voltage levels, weak fault currents, and are easily affected by factors such as arc instability and load harmonic interference, the problem of distribution network feeder grounding protection has not been effectively resolved, making small current grounding systems The ground fault detection protection in the field has become a reco...

AI Technical Summary

Problems solved by technology

However, especially for small current grounding systems, due to low voltage levels, weak fault currents, and are easily affected by factors such as arc instability and load harmonic interference, the problem of distribution network feeder grounding protection has not been effectively resolved, making small current grounding systems The ground fault detection protection in the industry has become a recognized problem in the industry

In the case of changing operation mode, it is impossible to fully describe the operating state of the system, and the fault judgment results are one-sided, which cannot meet the adaptive needs of relay protection in the dynamic environment of distribution network

Images