January 2012 Capital Investment - National Grid

Exhibit ___ (EIOP-19)Page 145 of 684Area DescriptionThe Southwest transmission study area includes the system as far north as GardenvilleWithin the Southwest study area, there are six distribution study areas: Cattaraugus – North,Chautauqua - North, Chautauqua – South, Erie - South, Olean and Wellsville.The North Cattaraugus study area serves approximately 14,700 customers. There areseven 13.2kV feeders, five of which are fed via two-115-13.2kV transformers at the Valleysubstation. The remaining two-13.2kV feeders are fed from 34.5-13.2kV transformers at thePrice Corners and Reservoir substations. There are also twenty 4.8kV feeders, all suppliedby 34.5-4.8kV transformers at various area substations. There are seven 34.5kV subtransmissionlines that provide supply for the 34.5-4.8kV transformers and a minimal numberof industrial customers that are supplied directly from the 34.5kV system. There are severalNYSEG substations and municipal electric departments supplied from the 34.5kV system.The North Chautauqua study area serves approximately 26,100 customers. There are ten4.8kV feeders, which are all fed from 34.5-4.8kV transformers. There are also twenty13.2kV distribution feeders with all but one fed by 115-13.2kV transformers at varioussubstations in the area. One 13.2kV feeder is supplied by a 34.5-13.2kV transformer at theWest Portland substation. There are also eight 34.5kV sub-transmission lines which providethe supply to the 34.5-4.8kV step-down transformers in the area.The Chautauqua South study area serves approximately 17,000. Customers are suppliedby twenty 4.8kV delta feeders, which are all fed from 34.5-4.8kV transformers. There arefour 13.2kV feeders with three fed by the Baker Street 115-13.2kV transformer and one fedby the French Creek 34.5-13.2kV transformer. There are five 34.5kV sub-transmission linesthat are supplied from Hartsfield and South Dow 115kV substations.The Erie South study area serves approximately 36,800 customers. The study areaincludes the Buffalo outer harbor area and those areas south of the City of Buffalo withapproximately half the feeders served at 13.2kV. The 115kV system supplies the 13.2kVstations. The rest of the feeders operate at 4.8kV or 4.16kV.The Olean study area serves approximately 18,700 customers. There are twentydistribution feeders that provide service to area customers. There are eight 4.8kV feederssupplied by 34.5-4.8kV transformers at various stations. Eleven of the area’s twelve 13.2kVfeeders are fed from 115-13.2kV transformers. The remaining single feeder is served from a34.5-13.2kV transformer at the Vandalia substation.The Wellsville study area serves approximately 4,400 customers. This study area is a smallrural region located near the Pennsylvania border and is supplied by the 115/34.5kVAndover and Nile substations. There are two 34.5kV supply lines in the area. Load isserved by 5 substations serving nine 4.8kV feeders.V - 31146