A Ground Fault Protection Method for Distribution Network Based on Fuzzy Metric Fusion Criterion

Abstract

The invention discloses a distribution network grounding fault protection method based on fuzzy metric fusion criterion, which includes: obtaining historical samples composed of various fault characteristic quantities of the protected feeder, and obtaining samples to be tested by the same method; adopting a clustering algorithm Divide n historical sample clusters into faulty and non-faulty classes; take membership degree, distance proportion measure and angle proportion measure as the similarity measure criterion respectively, calculate the fault measure value and non-fault measure value of the sample to be tested, and Construct the fuzzy metric fusion criterion matrix of the sample to be tested; take the fuzzy metric fusion criterion matrix as the evaluation set of the evaluation index system, construct the factor set of the evaluation index system with all the similarity measurement criteria, and preset the factor set of each element in the factor set The weight coefficient is used to judge the fuzzy metric fusion criterion matrix to obtain whether the distribution network to be tested is faulty or not. The invention widens the fault judgment interval, effectively avoids misjudgment caused by power system vibration and other factors, and improves robustness.

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...

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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

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