Vegetation Management
Pacific Gas and Electric Company
System and
San Francisco County Overview
Presented by
Joel Smith / PG&E
Forester
Area 1
Vegetation Management
Basic Electric System
Power Plant
Power Generated at
13 - 25 kV
• Nuclear
• Hydroelectric
• Geothermal
• Natural Gas
Transmission
Substation
Transmission Line
60, 115, 230 or 500 kV
Possible NERC regulation
Distribution Line
4, 12, 17 or 21 kV
Business
Home or Business
120 - 480 Volts
Home
Distribution
Substation
Compliance Requirements
PRC 4293 – Utility Vegetation Management - Tree Pruning/Removal
•
Maintain 4 feet of clearance between trees and primary distribution power lines and
60/70 KV transmission lines
•
Maintain 10 feet of clearance between trees and all transmission lines 115 KV and
above
•
Remove dead, diseased, defective and dying trees that could fall into the lines
(facility protection trees)
PRC 4292 – Utility Vegetation Management – Pole Clearing
•
Clear 10’ x 8’ cylinder around the base of subject poles and transmission structures
•
Remove dead vegetation up through the primary conductor level
CPUC G.O. 95 Rule 35 – Utility Vegetation Management – Tree Pruning/Removal
•
Maintain 18 inches of clearance between trees and primary distribution power lines
and 60/70 KV, greater clearances for higher voltages
•
Remove facility protection trees (as defined above)
•
Address situations where trees cause strain or abrasion on secondary conductors
NERC Standard FAC-003-1 – Vegetation Management Requirements for
Transmission
•
Minimum Clearance Standard based on voltage class
•
Zero tolerance for vegetation caused outages
3
California Regulations for
Distribution Lines
GO-95 Rule 35
PRC 4293
PRC 4292
18 in.
18 in.
4 ft.
HIGH VOLTAGE
8 ft.
4 ft.
10 ft.
Routine T&D Vegetation Management
Program Scope
•
Address through trim or removal, any tree that will encroach
within minimum clearance distances and any hazard tree to
maintain regulatory compliance.
–
–
–
–
113,00 miles of distribution line
19,500 miles of transmission line
70,000 square mile service territory
Trim or remove over 1.2M trees per year
•
5M trees in inventory with potential to “grow into” conductors
•
50M trees with potential to “fall into” conductors
•
Maintain fire breaks on 120,000 subject poles
•
Maintain transmission right of way
5
Zone
Tree Population
Trees Worked
Annually
Wire
5m
1.1m
Border
7-10m
50k
Fall
40m
30k
6
PG&E Distribution Tree
Trimming
•
The Routine Patrol Standard – Defined Scope of Work
– The Annual Patrol: Inspect 100% of overhead line,
identify and clear only trees that will encroach before next
cycle.
– Aggressively target trees up to 12” DBH, palms, and fast
growers for removal
– Pruning for 2 to 3 years clearance
– Hazard trees
– Strain or abrasion on secondary lines
– Pruning Standards – Utility Pruning BMP
– 600+ contract tree crews
– 350+ utility arborists/foresters
– Approx 60 PG&E office and field personnel
Territories
8
1) Right Tree Right Place
2) Work Practice
• Inspection, pruning and removal
• ROW and NERC Standards
3) Emergency
Operations
Tell me what’s missing…
10
Customer Interface
Consistent graphics and language to comprise our educational
presence across all communication channels to both internal and
external audiences.
City challenges…
230 Magellan
19 Maywood
217 Tocoloma
240 Casitas
“If a tree falls in the City, and there is no one there to hear
it, will it still…hit a car?”
Contact Information
Joel Smith, Forester (local project manager)
San Francisco and San Mateo Counties
• Office 650.985.5710
• Cell 650.477.8874
• jpsr@pge.com