Abstract: The third resonant slow extraction and RF-knockout technology was adopted for Xi'an Proton Application Facility (XIPAF), which was designed for proton single event effects research.The influence of dipole and quadrupole power ripple on extracted spill was explored theoretically and simulated via TrackAll.According to a series of simulation results, ΔI/I_set≤1.2×10^-4 for the quadrupole-focusing power converter, ΔI/I_set≤2×10^-3 for the quadrupole defocusing converter andΔI/I_set≤4×10^-4 for the dipole converter are acceptable, whereΔI represents the variance of the ouput current caused by power ripple and I_set represents the standard value of the output current without ripple.Since the synchrotron's power converters in XIPAF satisfy the same standard in terms of power ripple, it is confirmed thatΔI/I_setshould be limited to 1×10^-4 for all power converters.