An integrated power system model including both primary and secondary equipments is required by the integrated information platform for electric utilities to meet the actual demands of a variety of applications based on relay information. The grid model currently used by utilities contains basically only the primary model to the neglect of the secondary model. Following an analysis of the inadequacy of the protection model in the current common information model（CIM）， a CIM extended general protection model is presented， which is comprehensive， scalable and capable of shielding the differences between the protection devices of different vendors. The protection model has been applied in the decision-making system of China Southern Power Grid. Reults show that the proposed general protection model is efficient and feasible.