1. Pacific HVDC Tower Down April 28, 2015 Event Report to Operating Committee March 22, 2016
Kenneth Silver
Los Angeles Department of Water & Power
Chair, WECC OPEAS
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2. Western Electricity Coordinating Council
Introduction
On April 28, 2015 at 0606 hours, The Pacific HVDC Celilo-Sylmar Poles 3 & 4 Blocked Loading was approximately 1600-MW BPA RAS operated inserting the Fort Rock Series capacitors and dropping 1824-MW of generation. Frequency declined to approximately Hz returning to normal in 18 minutes. The cause was a truck striking and dislodging the tower base causing the tower to fall.
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Introduction
The +/-500-kV Celilo-Sylmar HVDC Line is an 845 mile long tie between northern Oregon and Southern California. The northern terminal is BPA’s Celilo Converter Station. The southern terminal, Sylmar Converter Station, is owned by five Southern California utilities, operated by LDWP. The fault location was Tower located in a remote area of east-central California, 40 miles s/o Lone Pine, California near Coso Junction.
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Tower Down
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5. Western Electricity Coordinating Council
Tower Down
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Tower Down
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7. Western Electricity Coordinating Council
Tower Down
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Tower Design
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Event – Action
What should happen?
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Sequence of Events
At 0606 hours:
Pacific HVDC Celilo-Sylmar Poles 3 & 4 block with approximately 1600-MW.
Automatic restart attempts fail.
BPA RAS inserts the Fort Rock Series Capacitors and drops 1824-MW of generation:
Grand Coulee 403-MW
Chief Joseph 836-MW
McNary 468-MW
The Dalles 116-MW
Kemano Unit 1 trips with 105-MW.
Frequency declines to approximately Hz.
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Sequence of Events
0607: All etags are cut and implemented by 0611 hrs.
0607: Peak RC requests all BAs suspend RBC
0609: San Juan 4 trips with 241-MW
0624: System frequency returns to normal. Peak RC lifts RBC restriction.
0700: The fault location is calculated to be 132 miles from Sylmar Converter Station.
0738: A manual test initiated at +/- 400-kV fails.
0921: LDWP Transmission Patrol helicopter reports Tower is down across a truck.
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Frequency
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Frequency
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PNM San Juan 4 & ACE
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LDWP ACE ( )
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CISO ACE ( )
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BPA ACE ( )
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COI ( )
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500-kV Bus Voltages
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Summary
The Celilo-Sylmar Line was restored to service at 0216 hours on May 1, 2015.
All relay and RAS actions were determined to be correct.
All system operator actions were appropriate and timely.
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Questions?
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