Southern Loop Coolidge Connector Project
In 2007, VELCO and Central Vermont Public Service (CVPS) proposed to construct the Southern Loop Coolidge Connector from Cavendish, Vermont, to Vernon, Vermont, to provide a redundant path and additional capacity to deliver power.
Needs & Benefits
Prior to the Southern Loop Project Coolidge Connector, Southern Vermont electrical transmission facilities had limited ability to support increased electrical demand and were unable to withstand failure of, or to have preventive maintenance conducted on, key components at existing demand levels. The reliability of the regional bulk transmission system that connects southern Vermont, southwestern New Hampshire and northwest Massachusetts was at risk at the existing demand levels, with increasing reliability risk as regional electrical demand levels increased.
The Southern Loop Coolidge Connector interconnects VELCO's electric transmissio network in southeastern Vermont and feeds the electric distribution system serving GMP (formerly CVPS) 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 local and regional 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 transmission network serving southern Vermont does not meet current federally mandated reliability requirements.
As outlined in VELCO's 2006 Long-Range Transmission Plan, the vulnerability of the current transmission network 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 substations using a robust design and a second transmission line.
- 52-mile 345 kV transmission line
- Vernon Substation construction
- Newfane Substation construction
- Coolidge Substation upgrade
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 visual impacts to the transmission upgrades are relatively minor for the majority of the Project due to the limited visibility of the Project uprades.Additional findings contributing to this conclusion are as follows:
- Views of the Southern Loop Project are limited along most the Project area
- The new 345 kV transmission line will be constructed within an existing transmission right-of-way
- The new 345 kV transmission line will be constructed adjacent to an existing line
- The design of the new line will utilize the same structure types and coordinate with the location of existing structures. This will coordinate with lines, allowing an organized appearance and ultimately reducing the visual presence of an additional line
- Proposed substation improvements are proposed for locations where existing transmission and distribution infrastructure are already included as part of the landscape
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 Project. A complete engineering noise analysis was provided as part of the Project's filing with the Public Service Board.
- Winter/Spring 2006
- Community working group
- Public meetings
- Fall 2007
- Regulatory & permitting process