SWAT Common Corridor Task Force Update

November, 2008

SWAT CC TF

• Mission Statement:– The Task Force is to establish the principles

associated with the determination of the separation distance of linear circuits that are in parallel in the same corridor.

• Deliverable:– White paper by end of CY 2008:– Audience: Members of the ACC

• Subject Matter Paper or Compilation of best engineering practices or how to optimize corridor utility

– Not intended to be a recipe book or cover all possible scenarios

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• Deliverable: continued– White Paper - will address and describe common

corridor structure separation issues:• System reliability, EMF impacts, land use, aesthetics, potential

increase with severance, Federal land issues, cost differences, WEC/NERC/FERC/DOE standards.

– BEST PRACTICES or PERMIT-ABILITY of structure separation structure differences and all trade-offs.

– Impacts to Reliability and Cost• Of placing a line in existing corridor from very close to very far

away

– 2 Conference Calls– 1 Meeting, Aug 29th

SWAT CC TF

• Presentations:• Greg Bernosky, APS

– Identifying New Transmission Line Corridors on Federally Managed Forests in Arizona

– “Our job is to document the conflict between electric reliability and land management”

– Forest use – Peak Fire Season Correlates to Peak Electrical demand

– Need to work w/USFS to evaluate current corridors and in determination of new corridors

– There are not lines drawn on a map but terrain types listed that are more conducive to infrastructure development

– Next Speaker…

SWAT CC TF• Mike Voda, SRP– Cost of Easement– Severance

• Odd shaped pieces created, difficult to zone w/owners intent• Severance is subjective, per appraiser, negotiated or determined by jury

– Structure Types horizontal, vertical, delta• Determination of Easement Widths• Insulator swing has influence on width of structure• Maintenance has influence on ROW width, live line

– Transmission Line Design• Minimum Total Cost = Land + Structures + Construction• Easement width and structure type = lowest cost?• Structural Design

SWAT CC TF

• Tom Wray, Southwestern Power Group– Review of State Transmission Corridor Guidelines– Researched siting laws, regulations and

guidelines governing construction of transmission facilities

– Researched to identify any guidelines for separation distance for parallel lines in a corridor

– AZ, CA, CO, ID, MT, NV, NM, OR and UT– There are no guidelines specifying distance

between transmission facilities

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• Ron Belval, TEP– System Reliability Impacts

• Examples drawn depicting potential reliability impacts due to failing into next line

• Too many lines in one corridor

• Brian Keel, SRP– FERC/NERC/WECC Standards or Guidelines

Applied to Transmission Corridors• NERC Standard common tower outage – Cat C

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– SRP continued• WECC Standard – Common Corridor Definition

– Contiguous right-of-way or two parallel rights-of-way with centerline separation less than the longest span length of the transmission circuits at the point of separation or 500 feet, which ever is greater, between the transmission circuits. This separation requirement does not apply to the last five spans of the transmission circuits entering into a substation. \

• Adjacent Transmission Circuit– Transmission circuits within a Common Corridor with no other

transmission circuits between them. Transmission Lines that cross but are otherwise on separate corridors are not Adjacent Transmission Circuits.

• WECC Standards– NERC C.5 with PBRC

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• Brian Keel, SRP continued.– PBRC, RPEWG, 7 Step Process of Performance Category

Upgrade Request

• Jaime Wood, EPG– DOE Draft Programmatic Environmental Impact

Statement, PEIS– PEIS – evaluates the environmental impacts of

broad agency actions, such as development of programs or the setting of national policies.

SWAT CC TF

• J. Wood, continued…– Example, Solar Energy Development PEIS,

analyze utility scale solar energy development on BLM administered lands in AZ, CA, CO, NV, NM & UT.

– Land Use Plans – set of decisions that establish management direction for the land within BLM admin areas

– Land Use Planning Process – is the key tool that the BLM uses to protect resources & designate uses on BLM lands

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– Implement Section 368 of the Energy Policy Act of 2005

– Designates corridors for the preferred location of linear facilities in agency land use and resource management plans on federal lands in 11 Western states

• Pipelines - oil, gas and hydrogen• electrical transmission and distribution lines • Schedule prompt action to identify, designate, and

incorporate the corridors into the applicable land use plans

– Intended to improve coordination among agencies to increase the efficiency of using designated corridors

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– Designating a system of energy corridors would not preclude an applicant from applying for a right-of-way outside of the designated energy corridors

– Local and project-specific impacts will be evaluated in the future at the individual project level

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– Section 368 energy corridors

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• Doug Saline, APS– Effect of Separation Distance on EMF– Magnetic Fields– Assumptions:– 500kV - ROW width allows for 100 foot from

middle of structure– 230kV – ROW width allows for 50 foot from middle

of structure

SWAT CC TFMagnetic Field for Different Separation Distances

500 kV Horizontal Configuration

0

20

40

60

80

100

120

140

160

-200 -100 0 100 200 300 400

Lateral Distance (ft)

Mag

net

ic F

ield

(m

G)

100 Ft 125 Ft 150 Ft 175 Ft 200 Ft

Conference Call items:1.800.490.7515Meeting Number = *1132743* make sure to enter the * in your entry.

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Magnetic Field for Different Separation Distances

0

2

4

6

8

10

12

-100 -50 0 50 100 150 200 250 300

Lateral Distance from Center (ft)

Mag

neti

c F

ield

(m

G)

50 Ft 60 Ft 75 Ft 100 Ft 125 Ft 150 Ft

175 Ft 200 Ft

230 kV Parallel Double Circuit Vertical Configuration

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– As separation distance increases, the magnetic field distribution across the ROW begins to emulate two independent magnetic field sources.

– Overall, the separation distance does not have significant effect on the magnetic field magnitudes (in terms of absolute quantities).

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• Ken Bagley– AZ/NM/NV State Land Management Use Criteria

• Neither AZ or NV in line siting or reliability business, reliability is not a concern in line siting

• More concerned about maximizing the value of the land• Each request to acquire state trust land looked at

independently, no clustering • NM seemed more amenable to siting on state trust• All prefer to use existing linear features