Charlotte, NC Downtown Underground Redesign Project

Duke Energy recognized a need to improve reliability and resiliency of the Charlotte, NC DTUG electric system, which could only be achieved by redesigning existing circuitry, such that the normal and emergency circuits be fed from different substations.  

 

Challenge 

Duke Energy recognized a need to improve reliability and resiliency of the Charlotte, NC Downtown Underground (DTUG) DTUG electric system, which could only be achieved by redesigning existing circuitry, such that the normal and emergency circuits be fed from different substations.   

The existing DTUG system design is comprised of automatic and manual switchgear that are served by a system of normal and emergency circuits, at two different primary voltages, whose origin is the same substation transformer bank.  TRC balanced the following conflicting parameters:  

• Design feeders from different substations – yet minimize duct/conductor lengths. 
• Install new conductors – yet maintain spare ducts for future expansion.  
• Minimize cost and construction – yet plan for known future growth. 
• Utilize existing infrastructure – yet where possible, retire 12kV and expand 24kV systems. 

Solution  

This project required a comprehensive redesign of the DTUG electric system, which included Cyme load flow analysis and balancing, contingency planning, cable pulling and duct/manhole routing, duct bank thermal load analysis, subsurface review, and a ten-year phased execution plan. 

Result 

TRC recommended the construction of a new substation and associated power distribution circuitry.  Our deliverables included stamped and electronic AutoCAD final drawings, depicting the overall design showing circuit routes, duct bank, manholes and vaults.  We produced manhole maps showing conduits and new circuitry, as well as subsurface engineering documentation of the existing space around infrastructure in the roadway to complete the new duct installation.  Circuit capacity studies were produced with the use of CymCAP design tool and summarized on a spreadsheet for all circuits to show the capacity at critical loading points on each circuit.  

In support of phase two of this project, TRC is helping to further refine the Ten-Year Phased Implementation Plan by breaking it down into individual work orders, so they can be handed off to construction. 

 

Client

Duke Energy

Project Location

Charlotte, North Carolina