Security and performance of wireless data transmission play important roles in smart grid system. To address these challenges, a frequency-hopping (FH) scheme is proposed for smart grid communication system in this paper. To endow power users various priorities, we present a new design of FH sequence set with various correlation properties, which is based on a novel type of sequence named no-hit-zone (NHZ) sequence set. Then, the error probability performance of the proposed system is evaluated by a comprehensive numerical analysis on power consumption measurement data. The simulation results demonstrate that the FH scheme with the proposed sequence set can improve the performance of smart grid system efficiently.