Converting Overhead to Underground

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Converting Overhead to Underground

• March 9, 2004
• APPA Conference
• San Antonio, Texas

Modesto C. Rodriguez, P.E. TD Engineer
III mcrodriguez_at_cps-satx.com [phone]
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Objectives

• Overhead to Underground
• Conversion Program Background
• Conversion Program Guidelines
• Projects Completed / In Work
• Project Selection Process
• Projects Selected for 2003

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Objectives

• We have come a long way since 1993 What have we
  learned?
• Joint Trench Issues
• Easements Permits
• Trench Alignment
• Rivers to Cross? Bridge Attachments

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Objectives

• Factors That Increase Project Costs
• Summary
• Questions

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Overhead to Underground

• Definition Conversion of overhead electric
  distribution lines to underground operation IAW
  CPS standards, specifications, and accepted
  engineering practices.
• CPS utilizes dead front, loop feed, pad mounted
  transformers with load break switches in primary
  loop systems.
• CPS converts the electric system up to the
  customers meter loop.
• Distribution Voltages Included 34.5KV L-L
  13.2KV L-L.

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Overhead to Underground

• When feeder sectionalizing is necessary, or for
  large multiple loads, CPS utilizes pad mounted,
  SF6 gas insulated, switchgear in underground
  primary loop systems.

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BITTERS RD. CONVERSION BEFORE
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BITTERS RD. CONVERSION
17,480 Ft Removal, Cost 2.182 Million
(124.82/FT)
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BITTERS RD. CONVERSION
17,480 Ft Removal, Cost 2.182 Million
(124.82/FT)
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BITTERS RD. CONVERSION
17,480 Ft Removal, Cost 2.182 Million
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ST. MARYS ST. CONVERSION BEFORE
29,875 FT Removal, Cost 1.82 Million
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ST. MARYS ST. CONVERSION
29,875 FT Removal, Cost 1.82 Million
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ST. MARYS ST. CONVERSION
29,875 FT Removal, Cost 1.82 Million
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Conversion Program Background

• On April 7, 1993, the CPS Board of Trustees
  directed staff to review design practices with
  the objective of modifying and incorporating
  aesthetic consideration (converting OH to UG)
  into its designs for electrical facilities.
• As a result of this request, numerous studies
  were conducted and results indicated it to be
  Cost Prohibitive to place facilities underground.
• Instead, in late 1993, CPS created a resolution
  amending the Capital Budget to include a budget
  to be known as the Overhead Conversion Fund.

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Conversion Fund Background

• The Funds are managed by the CPS General
  Accounting Department.
• Per resolution, the OCF budget is set at 1 of
  the electric revenue billed during the previous
  fiscal year to retail electric customers of CPS
  residing within the City, the Municipalities, and
  the Counties together with the balance of any
  amount budgeted in previous years not spent.
• Each of the 28 Municipalities and 8 Counties
  served by CPS has an appropriate fund allocation.

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Conversion Fund Background
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Conversion Program Guidelines

• The OCF can be used for the following items
• Convert Overhead Electric to Underground
  operation.
• Overhead facility modifications, i.e.. Relocate
  Overhead Electric.
• Modifications also include, replacing existing
  poles and cross-arms with aesthetic alternatives,
  steel poles.

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Conversion ProjectsCompleted / In Work

• A total of 40 projects have been completed since
  the inception of Overhead Conversion Fund.
• 2 projects currently in construction.
• 2 projects are currently in design.

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Project Selection Process

• In 1997, COSA adopted a formal project selection
  process.
• Candidate Projects are gathered by COSAs Capital
  Programs Division (CPD).
• CPD submits candidate projects to CPS for cost
  estimates. Total Cost UG Cost OH Removal -
  OH Material Salvage Value
• CPD evaluates and ranks projects.
• A Planning Commission reviews and selects
  projects to be implemented.
• CPD holds neighborhood association meetings to
  show the impact to the neighborhood.

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Project Selection Process

• Projects with favorable neighborhood association
  meetings remain on the list.
• City Council reviews and approves projects via a
  resolution authorizing the implementation of the
  project.
• CPS designs and plans the project utilizing CPS
  standards, specifications and accepted
  engineering practices.
• Based on construction workload, CPS may hire a
  contractor to complete the work.

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Projects Selected in 2003/2004

• 12 projects were selected.
• The estimated total cost for the 12 projects
  20.72 Million
• Status To date only 2 of the 12 project have
  been released/ authorized by resolution.
• The conversion process began with a bang!
  However, currently, the other utilities are
  refusing to participate in 10 of the 12 projects
  for free.

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We have come a long way since the inception of
the program What have we learned?
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Joint Trench Issues

• During the design phase consideration should be
  given to other utilities.
• Other Utilities (CATV, Tele.) voluntarily elect
  to participate in an overhead conversion job.
• Establish a joint trench sharing agreement that
  describes the methodology for determining each
  utilitys share of the joint trench costs.
• Collect the full charges as determined by the
  agreement prior to commencing!

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Easements Permits

• Acquire Easements First!
• Quickly follow-up with easement documents when
  given verbal permission to place lines
  equipment by the property owner.
• Mandatory for placement of padmount transformers.
  Optional for services unless a service crosses
  over the property to serve a neighbor.
• Acquire permits or approvals as may be required
  to gain access to easements or properties owned
  by railroads, state highways and commissions as
  early as possible.
• Special permits may be required if the area is of
  archeological significance.

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Trench Alignment

• Projects are usually selected in anticipation /
  coordination with Civic Improvement Projects.
• Select the most direct main trench alignment
  maintaining a consistent location within the
  street right of way keeping future CIPs in mind.
• Know where all existing and proposed facilities
  are located in effort to minimize conflicts with
  storm lines, inlets, water mains and sewer lines.
  Adjustments in elevation may be necessary.
• Avoid late fees associated with delays by
  managing the project closely while proactively
  resolving conflicts as quickly as possible.

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Rivers to Cross? Bridge Attachments
Roosevelt / Grove St. Conversion
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Factors That Increase Project Costs

• Costs can vary greatly from project to project.
• Scope/Size of the project. Paved Vs. Unpaved
  areas.
• Soil Conditions Dirt Vs. Rock. Standard Vs.
  Non-standard hours worked.
• Extra depth charges in effort to avoid conflicts
  with water mains, storm drains, storm drain
  inlets, fire hydrants and roadway elevation
  changes.
• Spare ducts to accommodate future circuit
  redundancy.

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Factors That Increase Project Costs

• Boring/Trenchless requirements under high traffic
  roadways, newly reconstructed streets, and
  railroads where open cuts are prohibited.
• Replacing OH switches and maintaining existing OH
  configurations utilizing padmount switchgear is
  costly.
• Submersible switchgear in Vaults.
• Dig ins.

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Summary

• Overhead Conversion Fund is alive and well.
• Mission accomplished.
• Future

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Questions?