SR-99 / Alaska Way Tunnel Project - Temporary Power - Seattle
The Alaskan Way Viaduct Replacement Tunnel is a bored road tunnel that is under construction (as of 2012) in the city of Seattle. It is scheduled to open in late 2015. The 2-mile (3.2 km) tunnel will carry State Route 99 under the existing Alaska Way viaduct from the SoDo neighborhood to South Lake Union in the north. The tunnel will be bored with the world's largest (as of 2013) tunnel boring machine (TBM). The tunnel boring machine is all electrical and is fed by a 20 MVA 26kV/26 kV isolation transformer. The distribution system also has one 5,250 kVA and 3,000 kVA transformers that feed the auxiliary equipment needed to support tunnel power and the TBM while under operation. Click here for more information about this project.
PowerStudies, Inc was hired to provide engineering support, review the temporary power (for the TBM and auxiliary equipment) system design, and perform power system studies. The PowerStudies, Inc engineers performed load flow, duct bank ampacity, motor starting, short circuit, protective device coordination, and arc flash studies.