Power consumption is a huge challenge for large scale systems, and power capping is an important goal of power management. Power overspending accumulative ratio ΔP×T is introduced as the metric to power capping. For large scale systems, NInO model is proposed to control the power consumption of clusters. Two example algorithms, NInO-P and NInO-ΔP, are designed based on NInO. Finally, the power capping with NInO is proved in experiments.