A Novel Fault Location Method for Unbalanced Active Distribution Networks With Sparse Hybrid Measurements

Existing fault location approaches necessitate the deployment of micro-phasor measurement units (μPMUs) at all terminal buses to achieve precise fault location on any line, leading to high costs and limited applicability in large, unbalanced active distribution networks (ADNs) with numerous branches. To address this issue, this paper proposes a cost-effective fault location method based on a sparse hybrid measurement scheme (SHMS), which replaces μPMUs on branches with conventional measuring devices (CMDs). First, a sparse fault current extraction method is proposed, and the conditions for the uniqueness of the sparse fault current solution are provided. Building on these results, a low-cost SHMS is proposed. Finally, a two-stage fault location method is presented to precisely locate faults on any line within ADNs. For the unbalanced IEEE 123-bus test system with numerous branches, the proposed method requires only 13 μPMUs and 32 CMDs—compared to the conventional requirement of 45 μPMUs—to locate faults on any line, thereby significantly reducing measurement costs. Simulation results indicate that, under diverse fault conditions, the fault location success rate reaches 98.30% for three-phase main lines and 96.16% for branches.