Study on hierarchical protection & control system in smart grid

To ensure comprehensive and multi-dimension safety of power grid, a hierarchical protection & control system is presented which is composed of traditional protections, substation and regional system based on wide area information. At first, the functions of hierarchical protection & control system are scientifically orientated and compared with traditional function items one by one. Then, the structure and functions of hierarchical protection & control system are studied. Three-layer structure is recommended, the construction scheme is also put forward. Finally, a number of key technologies and difficulties that exist in the process of system construction are proposed. Risks factors including data source, principle and algorithm, function cooperation, communication network, etc, should be identified and assessed. The corresponding contingency plans would be developed.