###### Abstract  
With the large-scale integration of renewable energy into distribution networks, traditional fixed-setting overcurrent protection strategies struggle to adapt to rapid fluctuations in renewable energy (e.g., wind and photovoltaic) output. Optimizing current settings is crucial for enhancing the stability of modern distribution networks. This paper proposes an adaptive overcurrent protection method based on an improved NSGA-II algorithm. By dynamically detecting renewable power fluctuations and generating adaptive solutions, the method enables the online optimization of protection parameters, effectively reducing misoperation rates, shortening operation times, and significantly improving the reliability and resilience of distribution networks. Using the rate of renewable power variation as the core criterion, renewable power changes are categorized into abrupt and gradual scenarios. Depending on the scenario, either a random solution injection strategy (DNSGA-II-A) or a Gaussian mutation strategy (DNSGA-II-B) is dynamically applied to adjust overcurrent protection settings and time delays, ensuring real-time alignment with grid conditions. Hard constraints such as sensitivity, selectivity, and misoperation rate are embedded to guarantee compliance with relay protection standards. Additionally, the convergence of the Pareto front change rate serves as the termination condition, reducing computational redundancy and avoiding local optima. Simulation tests on a 10 kV distribution network integrated with a wind farm validate the effectiveness of the proposed method. distribution network; adaptive current protection; multi-objective optimization; NSGA-II algorithm; renewable energy-integrated distribution network 2025202  
further improvement under DG integration. Scholars worldwide have conducted extensive research: Reference [5] conducted an evaluation of fault characteristic differences in differential protection for distribution networks containing distributed generators. It revealed that traditional current differential protection may lead to reduced transition resistance when applied to active distribution networks. In response to this conclusion, an adaptive current differential protection method was proposed by adjusting the phase angle constraints based on the proportional relationship of power frequency full current components at both ends of the line. Reference [6] addressed the fault current differences caused by boundary condition variations induced by Inverter-Interfaced Distributed Generator (IIDG) integration. By jointly calculating fault currents in distribution networks without IIDG and bus currents connected to IIDG, this study optimized setting value calculation time and improved computational accuracy. Reference [7] presented a composite sequence network current protection scheme for photovoltaic-integrated distribution networks, effectively expanding local protection coverage. However, its exclusive consideration of single DG integration makes it unsuitable for current multi-DG integration trends. Reference [8] proposed a DG access capacity calculation method considering distribution network current protection constraints, but imposed limitations on maximum DG integration capacity. Reference [9] introduced comprehensive protection improvement methods for multi-DG distribution networks, resolving the low DG permeability issue in traditional current protection. Nevertheless, this setting method fails to adapt to DG capacity variations. Reference [10] incorporated DG transient stability duration as temporal constraints in protection coordination, proposing a novel optimized coordination scheme for inverse-time overcurrent protection characteristics considering DG transient stability. Reference [11] implemented power flow calculation and fault analysis using system-wide synchronous state signals collected by the main station, then transmitted calculated current protection settings to individual protection devices via communication systems.