Vermont Electric Power Company (VELCO) recently said that it plans to formally apply to the Vermont Public Utility Commission on May 23 for approval of the company’s proposal to upgrade the Berlin substation.
The project entails equipment replacement and a fence expansion to accommodate a new control building, the company said.
As noted on the project webpage, the upgrade is needed because a recent conditions assessment revealed deficiencies within the substation. The transmission system upgrade would improve reliability of electric facilities serving portions of central Vermont, according to the webpage.
The original Berlin substation was built in 1982, with various modifications and improvements occurring over the nearly 37 years of service, the webpage noted, adding that VELCO’s conditions assessment identified such deficiencies in equipment as the protection and controls, 115-kV breakers, 34.5-kV breakers, switches, fence, and control building, the webpage noted.
VELCO proposes to address the majority of the substation concerns by upgrading the protection and control system and building a larger control building, the webpage noted, adding that other elements of the substation would be addressed by in-kind replacement and modifications of the existing equipment. Redundancy improvements of the alternating current (AC) and direct current (DC) station services would also occur, with that work requiring VELCO to expand the fence by about 15 feet on the substation’s west side, about 25 feet on the east side, and about 42 feet on the southeast side to accommodate the new control building, the webpage noted.
The proposed improvements to the substation would require the installation of a temporary 115/34.5-kV substation in order to maintain service to the Green Mountain Power (GMP) sub-transmission system, the webpage noted, adding that VELCO proposes to utilize the Barre temporary substation in support of the Berlin Project.
As noted on the webpage, the project components involve:
- Replacing the protection and control system with a system that provides diversity, redundancy and communication aided schemes
- Installing nine new 115-kV instrument voltage transformers in support of the new protection and control system
- Replacing the existing VELCO control building with a new control building that is able to accommodate the new protection and control system, redundant AC & DC station services, communication equipment and security systems. The new control building will be located on the southeast side of the substation, which will better facilitate the construction activities and future access
- Replacing the existing 115-kV circuit switcher with a 115-kV breaker and disconnect that meets VELCO’s design standards
- Replacing all three of the existing 115-kV breakers with new 115-kV breakers
- Installing a passive secondary oil containment system for the 115/34.5-kV power transformer
- Expanding the fence to accommodate the new control building, facilitate construction, and to improve access to equipment for maintenance
- Working with GMP to replace or relocate some of the existing 34.5-kV poles, so the poles are outside the fence
- Replacing an existing three pole 115-kV line structure with a single pole 115-kV structure to facilitate changes to the phasing of the K55 Line
A full analysis of potential aesthetic impacts and proposed landscaping to mitigate those impacts will be included with the petition filed with the commission, the webpage said, adding that VELCO does not anticipate adverse aesthetic impacts from the project. Also, a complete engineering noise analysis will be provided as part of the project’s filing with the commission, the webpage noted, adding that preliminary findings from VELCO’s noise consultant, Resource Systems Group, indicate no adverse impacts are expected at the residence closest to the substation.
According to the project timeline, if approved, project construction would begin in spring 2020 and the project’s anticipated completion date is winter 2020.