Toward smarter current relays for power grids

As the power systems in the United States become increasingly large, complex, and interconnected, the traditional relays are proving to be inadequate against blackouts. More "intelligent" relays are therefore needed to meet the security and reliability needs of the future power grid. In this paper, we propose a new logic for decision making and over-current relay setting. The proposed "smart" over-current relays can: 1) decide current settings with a new and more comprehensive logic; 2) use new technologies such as phasor measurement unit (PMU) and/or Global Positioning System (GPS) to improve decision making; and 3) establish communications between relays to get real-time information.