Dual-Feature-Driven Adaptive Differential Protection for Active Distribution Networks with T-Connected IIDGs

To address the issue that traditional pilot current differential protection, due to fixed restraint coefficients, struggles to balance sensitivity to high-resistance internal faults and selectivity for external faults after inverter-interfaced distributed generators are connected in a T-configuration to active distribution networks, an adaptive protection method based on the fusion of dual features is proposed. This method first constructs normalized differential current amplitude and the contribution degree of T-connected power sources to short-circuit current as a combined criterion. Subsequently, based on the contribution degree partition, a Gaussian kernel function is adopted to achieve smooth adaptive adjustment of the restraint coefficient within the fuzzy region. Compared with existing schemes that rely on voltage information or a single electrical quantity, this method realizes dynamic optimization of protection settings through the inherent correlation of dual features and fuzzy decision-making. Simulation verification based on a MATLAB/Simulink 10 kV distribution network model demonstrates that the proposed method significantly enhances operational sensitivity for high-resistance internal faults, reliably ensures selectivity for external faults and critical conditions, and effectively resolves the inherent contradiction faced by fixed parameter settings.