09-05-2014 BPU RPT 05 - Laserfiche WebLink

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'•ti A r l H f N v H !. I. F RIVERSIDE PUBLIC UTILITIES Board Memorandum PUBLIC UTILITIES BOARD OF PUBLIC UTILITIES DATE: September 5, 2014 ITEM NO: 5 SUBJECT: SUBSTATION GROUNDING STUDY -WORK ORDER NO. 1503436 ISSUE: The item for Board of Public Utilities consideration is approval of Work Order No. 1503436 to perform a substation grounding study. RECOMMENDATION: That the Board of Public Utilities approve the capital expenditure of $380,406 for Work Order No. 1503436 for a substation grounding study. BACKGROUND: The need for optimal grounding is becoming more acute as Riverside Public Utilities (RPU) incorporates digital relay and automation technologies into substations and protection schemes. Modern electronic equipment is much more sensitive than the devices they replace, and is dependent on appropriate grounding for all equipment. Signals associated with inferior grounding can result in the mis- operation of critical devices adversely affecting system reliability. A proper and complete grounding system is imperative for the safe and reliable operation of RPU's electrical equipment and for the safety of personnel and the public. RPU made significant improvements to the electrical system in recent years including the addition of power generators, the addition and reconfiguration of transmission lines and substations. Numerous additional substation projects are in various stages of design and construction. These projects greatly enhance RPU's ability to provide high quality and reliable electrical service to its customers. The improvements also modify fault currents within substations necessitating a thorough evaluation of all the grounding equipment as a system. Staff recommends conducting a comprehensive grounding study that will include field testing, analysis, recommended upgrades, and modelling of the grounding system at each substation to validate its adequacy and safety. With a valid engineering model, the impacts of future substation modifications can be determined in a straightforward and expeditious manner. The grounding study and analysis will be performed by a consultant from the Energy Delivery Engineering Consultant Panel and supervised by RPU engineering and operations staff.