System Projects - St. Johnsbury and Northern Vermont

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Vermont System Planning Committee > System Projects > St. Johnsbury and Northern Vermont

St. Johnsbury and Northern Vermont

Loss of St. Johnsbury 115/34/5 kV Transformer

Low voltage or voltage collapse in Northern Vermont for loss of transmission at either end

Loss of St. Johnsbury transformer

The loss of the St. Johnsbury transformer would result in the loss of all load at St. Johnsbury. This reliability deficiency is a CVPS subsystem issue. Proposed load growth at Burke Mountain, fed off Lyndonville Electric, prompted the completion of a first draft transmission analysis for this area in October 2007. The transmission solutions examined in the analysis conducted thus far are to install a second 115/34.5 kV transformer at St. Johnsbury with requisite substation expansion or the construction of a new substation, with one or two transformers, closer to the Lyndonville 34.5 kV feed. This project will be brought to the VSPC in 2008.

The map below roughly shows the area potentially impacted by this reliability deficiency.

Northern Vermont voltage issues

The potential for low voltage or voltage collapse in northern Vermont due to loss of transmission at either end of the state will begin to be addressed as part of the Lyndonville study listed above. The transmission solution examined in the analysis conducted thus far is installation of a reactive power device at the VELCO Irasburg substation with requisite substation expansion. The Lyndonville study proposes to improve the voltage by installing capacitor banks. This is primarily a bulk system issue that is the responsibility of VELCO.

The map below shows roughly the area of Vermont potentially affected by this reliability deficiency.