04-10-2023 BPU RPT 07 - Laserfiche WebLink

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W A T E R E N E R G Y L I F E P U B L I C U T I L I T I E S RIVERSIDE PUBLIC UTILITIES BOARD OF PUBLIC UTILITIES Board Memorandum SUBJECT: PLAZA SUBSTATION SWITCHGEAR DIFFERENTIAL UPGRADE PROJECT; AMOUNT OF $275,000 ISSUE: DATE: APRIL 10, 2023 NO. 4 REMOVAL AND 66KV BUS WORK ORDER 2312723 IN THE Approve the capital expenditure for Work Order No. 2312723 in the amount of $275,000 for the Plaza Substation Switchgear No. 4 Removal and 66kV Bus Differential Upgrade Project. RECOMMENDATION: That the Board of Public Utilities approve the capital expenditure for Work Order No. 2312723 in the amount of $275,000 which includes all design, construction, procurement, testing, commissioning, and construction support for upgrading the 66kV bus differential protection system and removing Transformer T4 and Switchgear No. 4 at Plaza Substation. BACKGROUND: Historically, the Riverside Public Utilities (RPU) primary distribution system was designed to operate at 4 kilovolt (kV) and the sub -transmission system voltage was designed to operate at 33kV. Over the years, this standard was revised to a higher voltage of 12kV for distribution and 66kV for sub -transmission. These higher voltages improve the stability and efficiency of the system, allowing RPU to serve a greater number of customers with safe and reliable power. RPU has gradually migrated to new voltage standards of 12kV and 66kV through designated projects. The 2010 Electric System Master Plan recommends voltage conversion projects to improve circuit reliability and outage restoration time for area customers. In 2022, electric utility crews completed the conversion of five 4kV feeders to 12kV infrastructure for the Magnolia Center and Wood Streets areas. Presently, those 4kV facilities are de -energized and physically abandoned in place at Plaza Substation. The equipment associated with those 4kV feeders is housed in a metal -clad switchgear which was used to control, protect, and isolate electrical equipment at Plaza Substation. That metal - clad switchgear also includes differential electromechanical relays and ancillary devices that are part of the 66kV bus protection equipment and not associated with the 4kV switchgear protection. These relays must be replaced and installed in a different location so that the switchgear can be demolished without compromising the protection system at the station.