Modal Information Integrated Single-Phase to Ground Fault Location Method

Due to the varied operating modes, short line lengths, and heterogeneous grounding media in distribution networks, developing an accurate, universally applicable fault localization method for single-phase grounding faults (SPGFs) remains a challenge. This paper presents a modal-information-integrated SPGF localization strategy for distribution networks, consisting of fault section localization and fault distance estimation. First, to ensure phase-frequency characteristic consistency across different measurement points, the selection range of characteristic signals and the quantitative calculation method are defined. A simplified fault-section identification criterion based on the phase relationships of characteristic signals has also been developed to accurately identify the section for various fault locations. Additionally, to address issues such as multiple solutions, solution instability, reliance on model parameters, and dependence on synchronous sampling faced by traditional impedance-based fault location methods in distribution networks, a rolling optimization method for fault distance is introduced, incorporating line-mode information fusion and a strong tracking Kalman filter (STKF). Meanwhile, an online process for identifying line parameters and phase-shift factors that account for asynchronous time synchronization is proposed. A series of simulation cases examining different fault conditions and actual faults validates the feasibility of the proposed approach.