Experience you can trust. Hurricane Hardening Commission Staff Workshop on Electric Utility...
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Transcript of Experience you can trust. Hurricane Hardening Commission Staff Workshop on Electric Utility...
Experience you can trust.
Hurricane Hardening
Commission Staff Workshop on Electric Utility InfrastructureRichard E. Brown, PhD, [email protected]
Tallahassee, FloridaJanuary 23rd 2006
Page 2© 2006 KEMA Inc.
About the Presenter
Richard E. Brown is a management and technical consultant for the electric power industry. He has published more than 70 technical papers related to power system reliability and infrastructure management; is a regular instructor on these topics; is author of the book Electric Power Distribution Reliability; and is a registered professional engineer. He is a senior member of the IEEE, chair of its working group on Distribution Planning and Implementation, and recipient of the Walter Fee Outstanding Young Engineer award. Richard earned his BSEE, MSEE, and PhD from the University of Washington in Seattle, and his MBA from the University of North Carolina at Chapel Hill. [email protected]
Page 3© 2006 KEMA Inc.
Agenda
Design criteria Hurricanes Hardening
Page 4© 2006 KEMA Inc.
Power Systems
GenerationPlant
GenerationSubstation
TransmissionTransmission
Substation
Subtransmission
DistributionSubstation
Distributio
nDistributionTransformer
ServiceDrop
Customer
Page 5© 2006 KEMA Inc.
Should a system be designed to withstand this?
Page 5© 2006 KEMA Inc.
Page 6© 2006 KEMA Inc.
Design Criteria
National Electrical Safety Code (NESC)– Grades of Construction– Extreme Wind Conditions
Reliability– Sometimes set by regulators– Sometimes set by utilities
Economic– Improve spending efficiency– Spend money to save money
Page 7© 2006 KEMA Inc.
NESC for Distribution Poles
Freeway crossings “Grade B” Railroad crossings “Grade B” Most other locations “Grade C”
Grade B is 50% stronger than Grade C
Page 8© 2006 KEMA Inc.
Distribution Pole Strength*
* Grade C is the minimum requirement for most distribution poles. Extreme wind based on 145 mph gusts.
0.0
0.5
1.0
1.5
2.0
2.5
3.0
WoodGrade C
WoodGrade B
Wood(Extreme
Wind)
ConcreteGrade C
ConcreteGrade B
Concrete(Extreme
Wind)
Rel
ativ
e S
tren
gth
.
Page 9© 2006 KEMA Inc.
HurricanesHurricanes
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Page 10© 2006 KEMA Inc.
Damage
Wind only
Trees
Debris
Flooding
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Page 11© 2006 KEMA Inc.
Wind Only
Hurricane Wilma was strong enough to snap concrete poles
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Trees
Tree damage is usually notpreventable by the utility
Page 13© 2006 KEMA Inc.
Debris
Flying debris is usually notpreventable by the utility
Page 14© 2006 KEMA Inc.
Flooding
Flooding can delay restoration efforts
Page 15© 2006 KEMA Inc.
HardeningHardening
Page 15© 2006 KEMA Inc.
Page 16© 2006 KEMA Inc.
Wind onPole
Wind Forces on a Pole Wind onConductors
Wind onAttachments
Page 17© 2006 KEMA Inc.
Design for Extreme Winds
Based on 3-second gusts
Extreme wind rating (equivalent)– Grade B 104 mph– Grade C 85 mph
Florida extreme winds– Southern Coast 145 mph– North Central 95 mph
Page 18© 2006 KEMA Inc.
Extreme Wind Speeds (3 second gusts)
Page 19© 2006 KEMA Inc.
Hurricane Categories
0
50
100
150
200
250
1 2 3 4 5Huricane Category
Win
d S
pee
d (
mp
h)
.
1 minute average3 second gust
104
85
145
Page 20© 2006 KEMA Inc.
“Storm Hardening” Toolkit
Stronger poles More guying Shorter spans Anti-cascading Conductor size Fewer attachments Undergrounding Vegetation management
Page 21© 2006 KEMA Inc.
Cost of Hardening
New 3-Phase Construction
– Typical Overhead: Typical cost– Hardened Overhead: 2 to 4 times typical– Underground: 5 to 10 times typical
Existing System
– Much more expensive– Much more complicated– Could take 15 to 30 years
Page 22© 2006 KEMA Inc.
Hardening“Roadmap”
Some Hardening Approaches
Entire system New construction Critical customer facilities Customer-driven Targeted hardening
10-20Years
Now