St. Johnsbury
About
Vermont Electric Power Company proposes to upgrade the St. Johnsbury Substation. The upgrade is needed because a recent conditions assessment revealed deficiencies within the substation. The transmission system upgrade will improve reliability of electric facilities serving portions of Vermont.
Needs & Benefits
The original VELCO St. Johnsbury Substation was built in 1972, with various modifications and improvements occurring over the subsequent nearly fifty years of serve. VELCO conducted a condition assessment of the substation and identified the need to replace some of the equipment due to condition. Deficiencies were identified in equipment such as the control building, 220 circuit switcher, 34.5 kV circuit breakers, protection and control relays, and the substation fence.
The project will require VELCO to install a temporary configuration and temporary 34.5 kV lines to maintain service to the GMP subtransmission system.
Components
The project consists of the following primary components:
- Replace the existing 25’ x 31’ VELCO control building with a new, approximately 32’ x 70’ control building that will accommodate the protection and control system, redundant AC & DC station services, communication equipment, and security systems. The new control building will be located on the southern side of the substation.
- Replace the existing 220 circuit switcher with a new K220 SF6 gas circuit breaker that meets VELCO’s design standards.
- Expand the fence to accommodate the new control building, and to improve access to equipment for maintenance. The substation fence expansion will be approximately 15 feet to the north, 15 feet to the west, and 55 feet to the south.
- Reconstruct and widen driveway to 20 feet with turn-around.
- Improve site drainage.
- Perform tree clearing to accommodate the temporary infrastructure, temporary substation/construction area support area, expanded substation yard and driveway improvements.
Impacts
VELCO's aesthetic consultant (T.J. Boyle Associates) reviewed the preliminary design plans and performed a preliminary visual analysis of the proposed Project upgrades. The findings indicate that the Project will not create any adverse aesthetics impacts. A full analysis of potential aesthetic impacts will be included with the Petition filed with the Public Utility Commission. VELCO does not anticipate adverse aesthetic impacts from the Project.
Project Timeline
- October – November 2023
- Public meetings
- Winter/Spring 2024
- Regulatory/permitting process
- Summer 2024
- Anticipated construction start
- December 2024
- Anticipated completion