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UYATEK ENERGY 11 r RIVERSIDE PUBLIC UTILITIES Board Memorandum P U B L I C U T I L I T I E S BOARD OF PUBLIC UTILITIES DATE: October 7, 2011 ITEM NO: 8 SUBJECT: fig KV DISCONNECT SWITCH AND BUS UPGRADES AT THE MOUNTAIN VIEW AND LA COLINA SUBSTATIONS—WORK ORDER NO. 1106327 ISSUE: Board of Public Utilities approval is requested for Work Order No. 1106327 RECOMMENDATION: That the Board of Public Utilities approve Work Order No. 1106327 in the amount of $1,060,000 for the 69 kV Disconnect Switch and Bus Upgrades at the Mountain View and La Colina Substations. BACKGROUND: The Mountain View and La Colina Substations are critical to Riverside's electrical system. These Substations were built in the 1960's with several transformer and breaker additions made throughout the years. However, most of the original disconnect switches are still in use. Under peak loading conditions and during the loss of one (t) transmission line [N-1 contingency loading], several 69 kV disconnect switches and associated 69 kV buswork at the Mountain View and La Colina Substations will be electrically overloaded for an extended period of time. This overload condition could potentially lead to customer power outages in neighboring areas. Therefore, upgrading these 69 kV disconnect switches and associated 69 kV buswork at the Mountain View and La Colina Substations will improve the reliability of the electric service. This project consists of upgrading a total of 16 69 kV disconnect switches and their associated 69 kV buses at the Mountain View and La Colina Substations. The quantity of 69 kV disconnect switches represents 40% and 50% of the switches at the Mountain View and La Colina Substations, respectively. Furthermore, each switch and its associated bus will be upgraded from a 600 ampere rating to a 1200 ampere rating. This project also includes replacement of all line surge arrestors at both the Mountain View and La Co[ina Substations. New surge arrestors will be more reliable and deliver better substation protection against voltage surges. In addition, two (2) new line disconnect switches will be installed at the La Colina Substation in order to allow expedient isolation of a 69 kV line from the Substation during a line outage. Electrical design will be performed by a consultant and reviewed by Riverside Public Utilities' (RPU) engineering staff. Electrical construction will be performed by RPU field forces.