69 KV Underground
Transmission Line Design & Installation
Project Location: Hewlett, New York
DST Team Leader: Hassan Khan
Challenge
PSEGLI required the development of a 69 kV underground transmission line spanning approximately 1.4 miles to connect a substation to a new riser pole.
A critical challenge involved performing a jack and bore crossing beneath an active MBTA railroad, which required rigorous permitting and coordination with multiple agencies.
The urban alignment also demanded careful civil design, including manhole grounding and duct bank routing, while ensuring electrical reliability through accurate conductor sizing.
Action
DST Engineers led the complete civil and electrical design for the underground transmission system.
Using CYME CAP analysis, the team performed thermal and conductivity evaluations to determine the optimal conductor size to meet PSEGLI’s load and performance requirements.
DST developed detailed construction drawings, trench sections, duct bank profiles, and grounding designs for manhole structures.
The team also managed all permitting activities, preparing and submitting a comprehensive permit package for approval by the MBTA and the City of Hewlett, including detailed engineering drawings, bore profiles, traffic management plans, and environmental compliance documentation.
DST coordinated closely with PSEGLI, municipal agencies, and the MBTA to streamline the approval process and enable the timely construction of the crossing and transmission route.
DST Value Addition
Engineered and permitted a 1.4-mile, 69 kV underground transmission route in a dense urban environment.
Designed and submitted a full permit package to the MBTA and local municipality, including bore crossing and civil layout details.
Conducted CYME CAP thermal modeling to optimize conductor size.
Designed a jack & bore crossing under active railroad infrastructure.
Developed and implemented grounding strategies for manhole installations.
Integrated system from the substation exit point to riser pole termination.
DST Value Addition
DST provided data, maps, charts, and calculations in a format easily accessible by ComEd.
DST successfully identified necessary grid upgrades and provided cost estimates for DER integration.
Throughout this program, DST ensured smooth communication and documentation, meeting regulatory and technical requirements for DER interconnection.
