An open-system approach to power system protection and control integration

Data packets based high-speed digital communications have opened the door for new types of applications in power system protection and control. The main obstacle in adopting Ethernet-type networks for time-sensitive communications was the data transfer characteristic of these networks. With baud rates in the gigabit-per-second range, the industry has started adopting the Ethernet networks as a viable alternative, not only because of their lower cost. This paper presents an open-system approach in which protective hardware equipment is designed to work in a clustered environment, sharing resources, data, and diagnostic functions with similar units. The Ethernet network, being capable to accommodate transparently a wide range of protocols, is used to connect the protective hardware. A model was developed for the Ethernet network to be incorporated into the power system simulation. The characteristics required from a digital relaying algorithm to be able to work with signal samples sent across data packets based networks are described in this paper. The proposed solution is implemented using a modified adaptive least-square-error algorithm and tested on a protection system that was integrated into the power system model.