Integrating SCADA, Load Shedding, and High-Speed Controls on an Ethernet Network at a North American Refinery

This paper discusses the implementation of an Ethernet communications network in a ring that connects substations in a closed communications loop at a large industrial facility. Data are transmitted at protection speeds and must be dependable for industrial power system operation and maintenance applications. The redundant electric power system Ethernet communications network is used for a supervisory control and data acquisition (SCADA) system that automates industrial electric power system operations. Within individual substations and between substations, communications based on IEC 61850 protocols eliminate copper control wiring, which results in reduced cost, construction time, commissioning time, and wiring errors and makes future upgrades simpler. A fast load-shedding system uses the same communications network to stabilize system frequency in response to a loss of generation by detecting the events that lead to a power deficit and automatically responding by shedding load to balance generation and load in less than 40 ms. This paper focuses on integrating three major electrical control systems at a refinery onto one Ethernet network: a SCADA system for controlling and monitoring operations, a peer-to-peer high-speed communications-assisted protection scheme, and a fast load-shedding system.