In flexible DC distribution networks with low-current grounding mode

single-pole-to-ground faults exhibit weak fault characteristics

making fault identification challenging. To enhance fault detection capability

this paper proposes a single-pole fault line selection scheme for flexible DC distribution networks based on K-means++ multi-criterion fusion. First

modulus decomposition of electrical quantities during line faults is carried out

and the characteristics of zero-mode current

zero-mode voltage and zero-mode power for both normal and faulty lines are obtained. Then

according to the differences in the Spearman correlation of zero-mode current

the cosine of the angle between zero-mode current and voltage

and the absolute value of the zero-mode power integral

three fault line selection criteria are constructed. Finally

the K-means++ algorithm is used to analyze the results of the three criteria for each line

enabling accurate identification of the fault line. Simulations in PSCAD show that the proposed method has strong resistance to transition resistance

noise interference

and communication delay

significantly improving the accuracy and reliability of single-pole-to-ground fault line selection.