Sandbar

About

Vermont Electric Power Company proposes to upgrade the Sandbar 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 northwest Vermont. 

Needs & Benefits

The original VELCO Sandbar Substation was built in 1975, with various modifications and improvements occurring over the nearly 50 years. VELCO conducted a conditions assessment of the substation and idenfitied the need to replace some of the equipment due to condition. Deficiences were identified in equipment such as the protection and controls, breakers, switches, foundations and oil containment. The addition of a new 115kV circuit switcher has been determined to be necessary to de-energize the magnetizing currents of the Phase Shifting Transformer. 

The equipment identified as needing replacement will be replaced in their current locations. New equipment determined to be installed as part of the Project will fit into the existing area and will not require a substation expansion. 

Components

The project consists of the following components: 

• Replace the existing VELCO control building with a new control building that is able to accommodate the new communication equipment, protection and control system, redundant AC & DC station services and security systems.  The new control building will be located in the southwest area of the existing Substation.
• Replace the existing protection and control system with a system that provides diversity, redundancy and communication aided schemes.
• Replace three existing 115 kV oil circuit breakers with new 115kV SF6 gas breakers.
• Replace three 115 kV instrument line voltage transformers on the K19 line.   
• Add a new 115 kV circuit switcher to de-energize the PST.
• Replace seven 115kV gang operated disconnects.
• Replace the passive secondary oil containment system for the 115kV PST.
• Replace approximately 75% of the existing perimeter fence to bring it up to current VELCO security standards and National Electric Safety Codes.
• Make necessary repairs to the ground grid due to disturbance caused by the addition of the new equipment and control building.
• Add new trench and conduit systems as necessary to support the addition of new equipment and control building.
• Replace original 115kV insulators with new.

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 aethetics 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. 

VELCO's noise consultant, Resource Systems Group, Inc. (RSG), will assess the potential noise impacts associated with the Project. A complete engineering noise analysis will be provided as part of the Project's filing with the Public Utility Commission. VELCO does not anticipate adverse impacts at the residences closest to the Substation. 

Project Timeline

• Summer 2019
  • Public meetings
• Fall 2019
  • Regulatory and permitting process
• Summer 2020
  • Construction start
• Fall/Winter 2020
  • Anticipated completion