The multi-level wide-area protection system scheme including substation level, regional-area level and wide-area level is proposed. Aiming to the different concerns, the protection & control schemes for the power grid in different levels are discussed. The data exchanged between the IEDs in the wide-area protection system is analyzed based on the system structure, and the collaborative mode between wide-area protection system and dispatch & monitoring system is also researched to optimize the protection & control schemes dynamically. The corresponding communication protocols are proposed for data exchange. In this system structure, the communication network for wide-area protection system is divided into several regional-area protection & control communication networks and wide-area protection & control communication network, which are distributed in two levels. The regional-area protection & control system is applied in Guangzhou power grid as one part of wide-area protection system, the feasibility and rationality of the technologies proposed are verified, which provides reference for the further research and application of the wide-area protection system.