Treasure Island and Yerba Buena Island Electric System Addressing Blackouts and System Reliability Update December 2021
Background
The Treasure Island Development Authority (TIDA) owns the electric system infrastructure on Treasure and Yerba Buena
Islands. The San Francisco Public Utilities Commission (SFPUC) operates and maintains the power system for TIDA, and
also provides electricity to residents and businesses on both islands.
The U.S. Navy transferred the electric system on Treasure and Yerba Buena Islands to TIDA in 1997. The existing
infrastructure is old and has exceeded normal life expectancy. The age of the system and condition of the equipment make the island more vulnerable to power outages.
Power outages arise when something interrupts the distribution of electricity through the system. These "faults" can result from a variety of causes, including fallen tree limbs, birds or other wildlife, and malfunctioning equipment.
Improving System Reliability
Near-term improvements have been completed in the past several months to improve the the reliability of the electric system.
New Switchyard and Switchgear: Constructed a new switchyard and installed a new switchgear to isolate certain fault events and prevent an island-wide outage.
New Fault Indicators and Reclosers: Installed numerous fault indicators and reclosers throughout the island, which assist crews in determining the location of a fault and limiting outages to just a portion of the system.
New Overhead Line: Installed and constructed a new overhead line from the switchyard, increasing the reliability of the main line serving both islands.
New Transformers: Replaced five old distribution transformers with new ones equipped with bird guards to prevent avian-related outages. Bird guards will be a standard component on all new transformers.
Bird Guards: Installed bird guards along Avenue l.
Vegetation Management: Removed palm trees to prevent palm fronds from falling on overhead lines.
Residential Reliability: Connected the residential neighborhood to its own circuit to mitigate the impact of faults from other parts of the island.
Relay Settings Updated: Adjusted the relays at the Port of Oakland Substation to allow the circuits and reclosers to better isolate a fault before it results in a system-wide outage
Above Ground System-Wide Inspection: Completed inspection of the entire distribution system and identified components to be replaced.
More Electric System Improvements Are Needed
Replacement of Damaged Crossarms and Transformers: A contract has been signed with an electrical contractor to replace the damaged crossarms and transformers identified during the system-wide inspection.
Continuous Inspections: Perform continuous inspections to mitigate potential system failures, including regular
Security Fencing: Install security fencing to protect the underground cables from Treasure Island to Yerba Buena Island from vandalism.
Protective Device: Monitor the protective device response and performance to further mitigate system-wide outages.
Tree trimming or removal
Questions?
Contact:
San Francisco Public Utilities Commission at:
(415) 554-3233 or email Peter Gallotta at pgallotta@sfwater.org
Treasure Island Development Authority at:
(415) 274-0660 or email TIDA@SFgov.org