Synchronized wide area communication has become a mature technology, which makes the real-time interaction between the substations and the wide area protection and control system possible. However, the present protection and control system to handle this real-time data has been recognized to be deficient. This paper begins by reviewing the development history of power system protection, with special attention paid to the recent development in the field of wide-area and integrated protections, in order to look into the future development of protection and control systems. Then the concept of integrated wide area protection and control is introduced, where it can be shown that a hierarchical protection and control system provides the protection and control for wide area or regional power substations/plants and their associated power networks. The system is mainly divided into three levels: the local, the substation/plant, and the wide area/regional. The integrated functions at each level are described in details with an aim to develop an optimal coordination mechanism between each level. The key element in the proposed system is the wide area real-time protection and control information platform, which not only enables the merger of three lines of defence for power system protection and control, but also provides a perfect tool for the application of cloud computing in substations and power networks.

This paper firstly outlines the background of recent development in smart grids with special attention paid to the field of power system protection, particular in the area of wide-area and integrated protections. The design of an integrated wide area protection and control is then introduced, where it can be shown that an integrated hierarchical protection and control system provides the protection and control for wide area or regional power substations/plants and their associated power networks. A synchronized wide area communication network is specially designed with an aim to support an optimal protection and control coordination at each level and between substations. One of the important elements of the system is the wide area real-time information platform which integrates the local and wide area protection and control functions.