Burns & McDonnell conducted a short-circuit and protective device coordination study for General Motors’ Worldwide Facilities Group. The primary purpose for this study was to be able to coordinate plant system operations based upon the available electric supply arrangement and identify all electrical system deficiencies that require correction. A secondary purpose for this study was to update and standardize the available site documentation for protective device coordination and equipment fault duties.
- Fault and Coordination Studies
Burns & McDonnell performed this study at four sites: Fairfax Assembly Center in Kansas City, Allison Transmission plant in Indianapolis, Arlington Assembly Center in Texas and Mansfield Metal Fabrication Plant in Ohio.
Burns & McDonnell performed electrical system data gathering of the electrical system at the sites. A model was then developed from utility interconnect voltage to the 480-V distribution to facilitate the execution of the short-circuit and protective device coordination studies.
An equipment evaluation report was prepared that indicates which equipment failed or was marginal with respect to being rated for the worst-case fault currents.
For each substation room, a layout drawing was prepared that shows the general arrangement of equipment within the room with an equipment elevation drawing showing the layout of the transformers, breakers and protective devices. A one-line diagram of the electrical equipment connectivity was also prepared, showing all relevant electrical devices. Time-current curves were provided for each substation, showing the coordination of the protective devices. Equipment ratings and additional system information were provided for each substation room.