[Objective] Under the dual-carbon target, coal-fired units are transitioning from operating under long-term stable loads to flexible operation. The deep peak shaving capability has become a critical indicator of the flexibility of coal-fired power units. However, deep peak shaving operations lead to rapid changes in the generator's hotspot temperatures, causing faults such as winding deformation, insulation wear, delamination, and wedge loosening. This paper investigates the operating state of the stator end of generators under deep peak shaving conditions. [Methods] Using COMSOL Multiphysics finite element analysis software, a multi-physics field coupling model for the stator winding was established, integrating electrical, magnetic, and mechanical fields. The vibration displacement of conductor bars and wedges was analyzed under two deep peak shaving conditions: rapid load variation and ultra-low load. Furthermore, to accelerate the adaptability of generators to deep peak shaving operation, two stator end structure optimization schemes were proposed. [Results] Simulation results showed that when the load changed at a rate of 5%/min, the vibration amplitudes of the straight section conductor bars, wedges, and slot exit conductor bars decreased by 21.19%, 99.7%, and 59.05%, respectively, compared to the original structure under rated conditions. When the generator operated at 30% load, the displacement reductions were 72.46%, 99.997%, and 53.85%, respectively. [Conclusion] After structural optimization, the displacement amplitudes of the straight section conductor bars, wedges and slot exit conductor bars under extreme rapid load variation conditions are significantly reduced, confirming the effectiveness of the optimized structure.