Special protection scheme (SPS) is an important technology to enhance the reliability of power grid. In SPS, communications are needed to convey information and coordinate the actions. In this paper, wireless communications are proposed for the SPS system due to its low cost and fast deployment. Due to the high requirement on the reliability of SPS system, it is of key importance to improve the reliability of the wireless communication infrastructure in SPS, since wireless communications are subject to various random factors such as noise, fading and interference. Hence, the framework of reliability engineering is applied to the resource allocation of wireless communication links, i.e., how to allocate the spectrum bandwidth to various links such that the overall system reliability is maximized. To that goal, a general model of SPS is adopted and the resource allocation is modeled as constrained optimization problems. Both cases of exclusive resource allocation and spectrum reuse are considered. Numerical simulations show that the reliability engineering for the wireless communication links can significantly improve the reliability of SPS systems.