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Bennington Substation Project

Vermont Electric Power Company (VELCO) is proposing to construct a substation north of the existing substation in Bennington, Vermont, to provide a redundant path and additional capacity to deliver power to this area.

VELCO's existing Bennington substation, located on Woodford Road, interconnects VELCO's electric transmission network in southwest Vermont. The southwest Vermont electric distribution systems are fed from VELCO's transmission network serving CVPS and GMP customers. Failures of key transmission components would low-voltage conditions that violate system standards, voltage instability/collapse, or thermal overloads, which could result in extended outages for the areas served by the transmission system.

Transmission utilities, such as VELCO, are required to design, operate and maintain a transmission network according to national and regional reliability standards. Planning studies by VELCO and ISO New England, New England's bulk electric system provider, reveal that the existing Bennington substation does not meet current federally mandated reliability requirements.

As outlined in VELCO's 2009 Long Range Plan, the vulnerability of the current substation design results in system reliability problems, which under certain circumstances may lead to loss of service, system outages and low voltage. These concerns can be addressed by constructing the proposed substation using a robust design such as a ring bus or a breaker-and-a-half substation. Building a new VELCO Bennington substation with a new six breaker ring substation to connect the two transmission lines serving southwest Vermont will resolve current reliability criteria violations that result from a single transmission element's failure at the substation.

The proposed project will include the following components

  • 115 kV aluminum bus structure
    • six circuit breakers
    • transmission control building
    • connection to VELCO's existing 115kV transmission lines
    • three transformers
    • two capacitor banks
  • 46 kV aluminum bus structure
    • three circuit breakers
    • distribution control building
    • connection to CVPS' existing 69 kV distribution lines

VELCO and CVPS will be constructing a new transmission corridor, to connect the new stations to the existing transmission and sub-transmission lines. All of the VELCO Bennington substation at the existing site will be decommissioned and a portion of the existing CVPS Woodford Road substation will be decommissioned.

See our glossary of electrical terms for definitions of these components.

Project Impacts

VELCO's aesthetic consultant has reviewed the preliminary design plans and performed a visual analysis of the areas of the proposed Project. The findings indicated that the Project has the most potential visibility to the general public from areas west of the proposed substation. There is likely to be intermittent views to portions of the substation from a variety of locations in Bennington, including views form the Bennington Monument. Potential views from the northern segment of the Bennington Bypass will be partially, if not significantly screened by adjacent vegetation to the bypass. A full analysis of potential aesthetic impacts and proposed landscaping mitigation measures will be included with the Petition to be filed in May.

VELCO's noise consultant will assess the potential noise impacts associated with the substation relocation. A complete engineering noise analysis will be provided as part of the Project's filing with the Public Service Board. VELCO expects a decrease in noise at the existing site and no noise impacts to the closest residence at the new site.

Subject to Public Service Board approval, construction will begin in the spring of 2012 with a targeted completion date of January 2013.