The objective of relay protection can ensure the safe and stable operation of power grid as far as possible, and the protection configuration schemes have different influence on power grids. This paper analyzed the reasons of protection failure, established the Markov model for the evaluation of relay protection reliability in different schemes and studied its reliability by using state space method. On the basis of the researcher results, this paper further investigated the influence of economic factors, such as cost, fault loss and so on, which could more comprehensively reflect the different effect of configuration schemes and provide references for the analysis and evaluation of protection configuration schemes in practice.