Bennington Substation Project
In 2011, VELCO proposed to construct a substation north of an existing substation in Bennington, Vermont, to provide a redundant path and additional capacity to deliver power to the Bennington area.
Needs & Benefits
The Bennington substation interconnects VELCO’s electric transmission network in southwest Vermont and feeds the electric distribution system serving GMP customers. Failures of key transmission components cause 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 Transmission 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.
- 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 GMP’s existing 69 kV distribution lines
Now completed, VELCO and GMP constructed a new transmission corridor, to connect the new stations to the existing transmission and sub-transmission lines. All of the VELCO Bennington substation components at the existing site were decommissioned and a portion of the existing GMP Woodford Road substation was decommissioned.
VELCO's aesthetic consultant reviewed the preliminary design plans and performed a visual analysis of the areas of the proposed Project. The findings indicated that the Project had the most potential visibility to the general public from areas west of the proposed substation. Projected impacts included 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 are partially, if not significantly screened by vegetation adjacent to the bypass. A full analysis of potential aesthetic impacts and proposed landscaping mitigation measures was included with the project petition.
VELCO's noise consultant assessed the potential noise impacts associated with the substation relocation. A complete engineering noise analysis was provided as part of the Project's filing with the Public Service Board. VELCO projected a decrease in noise at the existing site and no noise impacts to the closest residence at the new site.
- Spring 2011
- Public meetings
- Regulatory & permitting process
- Spring 2012
- Construction start
- Fall 2013
- Construction complete