09-05-2014 BPU RPT 06 - Laserfiche WebLink

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W A T E R E N E R G Y f T t RIVERSIDE PUBLIC UTILITIES MW& Board Memorandum PUBLIC UTILITIES BOARD OF PUBLIC UTILITIES DATE: September 5, 2014 ITEM NO: 6 SUBJECT: SUBSTATION UNDERGROUND ELECTRICAL CABLE STUDY - WORK ORDER NO. 1421209 ISSUE: The item for Board of Public Utilities consideration is approval of Work Order No. 1421209 to perform a Substation Underground Electrical Cable Study. RECOMMENDATION: That the Board of Public Utilities approve the capital expenditure of $204,213 for Work Order No. 1421209 for a Substation Underground Electrical Cable Study. BACKGROUND: Riverside Public Utilities (RPU) has 123 12 and 4 kV circuits that provide power to Utility customers. Each circuit has a maximum power rating based on the mechanical characteristics of the cable at the substation source. Over many years, RPU engineers used standard industry assumptions to determine the maximum power rating for each circuit. Recent projects at the Casa Blanca and Plaza Substations have proven that these assumptions are far too conservative and result in unused capacity available to serve electric customers- A system wide Electrical Cable Study will provide detailed information for the maximum power rating on each circuit. This information will ensure maximum utilization of each circuit. It will provide increased confidence when planning upgrades to existing power cables and when designing new circuits. Furthermore, the results from a cable study will aid in making more intelligent operational decisions and setting appropriate supervisory control and data acquisition (SCADA) alarms. Staff recommends completing a comprehensive Electrical Cable Study that will include empirical data, physical parameters and computer modeling of the cable system at each substation. Results will be captured in a detailed report. Computer models of the substation cable system will streamline future engineering designs and optimize the use of the electric system infrastructure as the system grows by avoiding investment in unnecessary infrastructure. The Electrical Cable Study analysis will be performed by a consultant from the Energy Delivery Engineering Consultant Panel and supervised by RPU engineering and operations staff.