January 2012 Capital Investment - National Grid

Exhibit ___ (EIOP-19)Page 74 of 684Metal-Clad SwitchgearDeteriorated metal-clad switchgear can be prone to water and animal ingress whichleads to failures from moisture, dust or animals. Visual surveys will detect suchdegradation, but cannot identify surface tracking where hidden behind metal enclosures.Identification of these concerns is more likely with electro-acoustic detection techniques.By using sensors to detect anomalous sound (acoustic) waves or electric signals in themetal-clad switchgear, it is possible to identify equipment condition concerns beforefailure. An initial review using this technique identified a number of locations for furtheraction as part of this strategy.For each substation, an analysis will be conducted to determine if direct replacement isthe best course of action or if an alternate means of supplying the load will beconstructed.Drivers:Metal-clad switchgear installed prior to 1970 have several factors that can lead tocomponent failure. Electrical insulation voids were more prevalent in earlier vintageswitchgear. Higher temperatures due to poor ventilation systems can degradelubrication in moving parts such as breaker mechanisms; and, gaskets and caulkingdeteriorate over time leading to ingress of moisture.Customer Benefits:The impact of each metal-clad switchgear event on local customers is usuallysubstantial, with nearly 3,000 customers interrupted for over three hours per event. Thisprogram would reduce the risk of such events and provide significant benefit to theaffected customers.2011 to 2012 Variance:The projected program investment is shown in the table below. The capital forecastreflects a prioritized replacement schedule for switchgear replacement based oncondition assessment data and analysis.Table III-12Metal-Clad SwitchgearProgram Variance ($millions)CIP FY12 FY13 FY14 FY15 FY16 FY17 Total2011 3.7 2.6 - - - - 6.32012 - 4.3 6.2 - - - 10.4The following specific projects are forecasted to have spending in excess of $1 million inany fiscal year:• Project C25139, Replace 13.8kV Metal-Clad Switchgear at Oneida Substation.Replace metal-clad substation at Oneida substation with new metal-cladswitchgear.• Project C36104, Ash Street Replace Metal-Clad. Replace 12kV metal-cladsubstation at Ash Street substation with new open-air bus station.III-16 1675