A Differential Protection for Active Distribution Networks Based on Additional Fitting Factor

The difference in the amplitude and phase of the current before and after a fault forms the basis of current differential protection (CDP). With the large-scale integration of renewable energy into the distribution network, the current amplitude and phase exhibit significant uncertainty, presenting challenges to conventional CDP. To address this issue, this paper constructs an adaptive restraint current and establishes an operating boundary model based on the adaptive restraint current. Then, an additional fitting factor is introduced according to the trend of basic parameter changes in the model, to ensure the feasibility of the scheme under high-resistance faults. Finally, the performance of the scheme is demonstrated by using the PSCAD/EMTDC simulation platform. The simulation results show that the scheme can operate under different fault resistances and maintain high sensitivity and speed.