Eversource has completed the $190 million Eastern Connecticut Reliability Program, which comprises various upgrades to the electric grid, including infrastructure improvements to local substations and transmission lines, enhancements to system reliability and communication between substations to assist customers.
The group of reliability projects in Montville, Ledyard, Preston, Stonington, North Stonington, Lebanon and Killingly are completed, which contain upgrades at five substations, converting lower voltage transmission lines to 115 kV lines, installing new communication wire to enhance coordination between substations and replacing existing transmission towers with stronger steel structures.
The upgrades included the installation of a clean air circuit-breaker at Eversource’s substation in Preston. These are safety devices to help protect the system from damage by an overcurrent.
The clean air breaker helps eliminate significant volumes of SF6, a greenhouse gas for insulation of high-voltage switches in transmission systems across the country, while maintaining reliability.
A synchronous condenser was also installed at a North Stonington substation. It supports system reliability by providing dynamic voltage control to reduce the possibility of outages in certain situations while meeting specific needs of the transmission system for the region.
