The Tesoro SLC oil refinery recently completed several upgrades aimed at improving power system reliability and flexibility, including the ability to continue operations when islanded from the utility grid. Because of a generation deficit within the refinery, the system required a load-shedding scheme to allow islanded operation.
POWER made use of IEC 61850 GOOSE messaging, originally employed for the reliability upgrade, as a solution for the load-shedding scheme platform. All of the Intelligent Electronic Devices to be included in the load-shedding scheme had IEC 61850 capabilities, so the only additional hardware required for the load-shedding project was a new load-shedding controller.
Services and Features
- Analyzed performance: Gathered details on the refinery load and generation.
- Modeled performance: Modeled system performance under loss-of-utility-feed conditions.
- Identified solution: Specified controls that would preserve required loads under these conditions.
- Bumpless transfers: When the refinery is islanded, the solution sheds non-critical loads very quickly to allow the on-site generation to carry critical loads without interruption. Solution also delivers uninterrupted return to utility power.
- Thorough testing: Bench testing validated operation of the load shedding scheme under normal conditions as well as failure modes.
- Real Time Digital Simulator (RTDS): Hundreds of tests verified scheme performance under dynamic conditions.
- Installation commissioning: Site testing occurred during a plant outage and consisted of a subset of tests performed earlier.