The invention discloses a high-resistance grounding fault detection method based on a flexible DC distribution network. The high-resistance grounding fault detection method comprises the steps of: firstly, extracting a
feature model IMF1 component of a transient zero-mode current by adopting a complementary ensemble empirical mode
decomposition algorithm, performing first-order differentiate operation on the IMF1to obtain a sudden change singular point, calculating a cumulative slope sum in the vicinity of the singular point, and distinguishing a faulty state and a
normal state through comparing a slope sum value with a starting threshold value; and secondly, adopting a Prony
algorithm for carrying out parameter identification on the IMF1 component to obtain a feature frequency component and a
direct current component in the IMF1 component, calculating an energy ratio of the feature frequency component to the
direct current component, and further distinguishing different states according to the difference of the energy ratio numerical values. Compared with the existing methods, the high-resistance grounding fault detection method can adapt to accurate
feature extraction under a strong
noise environment, has the advantages of self-adaptability, convenient application and high detection precision in the
feature extraction process, can determine the operating state of the distribution network
system incisively, and increases the calculation speed.