Modular, object-oriented architecture for protective relays

Multi-functionality and integration in command and control systems put new challenge to power system protection and control equipment. As protection relays become more complex and stringent requirements apply to its communication capabilities, the need for a more powerful solution increases. This paper presents an object-oriented architecture for protective relays, based on a modular software organization. A standard solution for different types of protection devices is proposed. The hardware and software platforms, as well as the graphical interface application are described. Its main benefits are system upgradability and maintainability. Functional classes, corresponding to well-defined protection and automation functions or other configuration data, are considered. Object-oriented programming methodology plays a decisive role in the design options. A global evaluation of today's solution for the substation protection and automation task and a discussion of future trends are presented.