Fault Section Location Method for Distribution Network Based on Combination of Magnetic Field and VMD-HHT

When a single-phase grounding fault takes place in a non-effectively grounded system, the fault current is feeble and the fault characteristics are not distinct. This paper explores the magnetic field distribution beneath overhead lines and its relationship with three-phase currents to address the challenges of section location in current distribution networks. A non-contact fault location method based on magnetic fields is proposed. First, the orthogonal dual-axis magnetic field signals are synthesized, and then the synthetic magnetic field undergoes Variational Mode Decomposition (VMD) to obtain its corresponding frequency components. Subsequently, the highest and lowest frequency components are processed using the Hilbert-Huang Transform (HHT). Construct instantaneous energy criteria for the highest frequency component and instantaneous polarity and phase criteria for the lowest frequency component. A multi-criteria localization method based on microscopic instantaneous feature quantities was constructed from the perspectives of instantaneous energy, instantaneous phase, and instantaneous polarity. Tests were conducted in an ungrounded system, and the results showed that the method has accurate positioning results and strong feasibility.