January 2012 Capital Investment - National Grid

Exhibit ___ (EIOP-19)Page 144 of 684V H. SouthwestArea SummaryThe driver behind the transmission capacity related projects in the Southwest study area is:• A wide range of contingencies can result in voltages well below criteria at variouslocations in this study area. The vulnerability of the area to these voltage issues issignificantly amplified if certain key generators are not operating.Key sub-transmission and distribution drivers include the following:• The 34.5kV sub-transmission system that consists of several very long loops thattraverse through rugged territory.• Asset condition issues at Steamburg station.V - 30145