This invention belongs to the field of
cluster analysis technology, specifically relating to a method for identifying malfunction patterns in
relay protection based on
cluster analysis. The method includes: collecting fault waveform data, extracting current surges, the proportion of zero-sequence components, and the second
harmonic ratio, and constructing a
feature set after normalization; calculating the local sparsity of samples based on the KNN
algorithm, and constructing a density adjustment factor by combining the logarithmic difference of sparsity with an energy gating term; generating a dynamic
radius using the density adjustment factor to replace the fixed search threshold in the clustering
algorithm, and introducing shared nearest neighbor
verification to remove pseudo-connected samples to construct a time-series cluster; based on the statistical characteristics of the time-series cluster, if the second
harmonic ratio exceeds the limit, it is determined to be an
inrush current and blocked; otherwise, a metallic or high-resistance grounding fault is determined based on the current surge and the duration of the zero-sequence component proportion. This invention solves the problems of difficulty in capturing sparse fault features and difficulty in identifying malfunctions by dynamically adjusting the cluster search range.