Customer MeetingApril 28, 2010

Torrington, WY

AgendaIntroductionsAccomplishmentsUpdate on Torrington AreaPVVC OverviewPVVC Schedule and Cost EstimatesQuestions/CommentsWrap Up

Accomplishments since 2003Whiterock Substation (2005)Lingle Tap (2003)Lyman-Yoder Tap (2005)McGrew area Caps (2005)Stored mobile transformer at Guernsey Rural

(2004)Wood Pole Testing and Treatment (2003 &

2004)Letter of Concurrence between Tri-State and

Western on Platte Valley conversion project (2005)

Glendo Substation Relay System & RTU replacement

Accomplishment since 2003Gering Station Service Switchgear (2006)

Gering PCBs 162, 462, 966 replacement (2006)

Glendo PCB 524 (2006)

Limestone additions (PCB 442, new control & relay system, new RTU) (2009)

Repaired Mobile transformer and returned to Guernsey Rural (2009)

Upcoming Projects (2008-2011)Torrington transformer KY2A addition (In-service

May 2010)

Gering-Gering Valley 34.5-kV rebuild (2011)

Torrington KY2A additionProject to add 115/34.5-kV 50 MVA

transformerJoint project with City of TorringtonTransformer delivered - Oct 2008Construction contractor complete – Dec 2008Control Design & switchboard deliveredCommissioning ongoing

Platte Valley Voltage ConversionThe objective of the Platte Valley Voltage

Conversion Project is to convert the operating voltage of the 34.5-kV transmission lines and related facilities between Lingle Substation and Sievers Rural Substation to 69-kV.

The lines were rebuilt in the early 90’s to 69-kV standard.

Platte Valley Voltage ConversionThe majority of the work is converting the

numerous substations and taps along the line segments to 69-kV.

Western and Tri-State signed a Letter of Concurrence in November 2004 laying the initial scope and responsibilities for the upgrades.

Platte Valley Voltage ConversionScope:Lingle Substation: Install a 115/69-kV 40 MVA

transformer and associated equipment.

Torrington Substation: Install a 69/34.5-kV 50 MVA transformer and associated equipment.

Sievers Rural Tap: Install a 69/34.5-kV 25 MVA transformer and associated equipment.

Construct eleven miles of new 69-kV line between East Morrill Tap and Sievers Rural Tap.

Platte Valley Voltage ConversionScope (cont):Torrington Rural Tap: Replace transformer and

rebuild high side for 69-kV.

Henry Tap: Replace transformer and rebuild high side for 69-kV.

Village of Morrill Tap: Make necessary modifications to operate existing dual winding transformer at 69-kV.

Connect the Town of Lingle Tap to the Limestone-Lingle 34.5-kV line.

Platte Valley Voltage ConversionScope (cont):

Estimated Cost: $21MPlanned ISD: FY2015Project Manager: Roy GearhartCurrent Status: Not planned to start until

FY2012. System Studies updated every two years. System Studies planned for 2010.

Platte Valley Voltage ConversionMajor Milestones to date

Various System Studies: 2000-2010Meeting with Platte Valley Customers: April 2003Western and Tri-State signed Ltr of Concurrence:

November 2004Meeting with Platte Valley Customers: April 2005Meeting with Platte Valley Customers: April 2007

Published Platte Valley Voltage Conversion Project Overview: January 23, 2006

Platte Valley Voltage ConversionLingle Substation

Scope:115kV/69kV 40MVA transformer with high and low side interrupters for protection.New Substation site required for 115/69kV additionsNew Control Building

Schedule: 2012-2015

Estimate: $4,730k (In 2014 $’s)

Platte Valley Voltage ConversionLingle Town

Scope: Move connection to Limestone 34.5-kV line with ~0.5 mile of new 34.5-kV line.

Schedule: 2012-2015

Estimate: $100k - $200k (no detail estimate done)

Platte Valley Voltage ConversionTorrington Rural

Scope:Convert to 69-kV with a 69kV/12.47kV 5MVA and a 69kV/24.9kV 7.5MVA transformers and 69kV improvements on high side.

Schedule: 2012-2015

Estimate: $1,500k (In 2014 $’s)

Platte Valley Voltage ConversionTorrington Substation

Scope:New 69-kV yard with 4–69kV bays; 69kV/34.5kV 50MVA Transformer; New Control Building; more land.

Schedule: 2012-2015

Estimate: $5,400k (In 2014 $’s)

Platte Valley Voltage ConversionHenry

Scope:Convert to 69-kV with a 69kV/12.47kV 7.5MVA transformer and 69kV improvements on high side.

Schedule: 2012-2015

Estimate: $900k (In 2014 $’s)

Platte Valley Voltage ConversionVillage of Morrill

Scope:Convert to 69-kV high side winding on existing 34.5/69/7.2/12.47kV 2.5MVA transformer and 69kV improvements on high side.

Schedule: 2012-2015

Estimate: No estimate done

Platte Valley Voltage ConversionEast Morrill Tap – Wildcat 69-kV line

Scope:Construct ~3 miles of new 69-kV line from East Morrill tap to Wildcat. Creates the Lyman-Wildcat 34.5-kV line. Allows Village of Lyman and Lyman Rural loads to remain 34.5-kV

Schedule: 2012-2015

Estimate: $1,395k (in 2012 $’s)

Platte Valley Voltage ConversionWildcat Substation

Scope:No new additions initially planned at Wildcat. Should the system needs change, the new Torrington-Sievers Rural 69-kV line could be interconnected with the 34.5-kV system at Wildcat to provide system reliability improvements.

Platte Valley Voltage ConversionWildcat-Sievers Rural 69-kV line

Scope:Construct a new 10 mile 69-kV line between Wildcat and Sievers Rural to bypass Mitchell area.

Bypasses City of Mitchell and Mitchell Rural loads, leaving them at 34.5-kV

Schedule: 2012-2015

Estimate: $4,045K

Platte Valley Voltage ConversionSievers Rural

Scope:69/34.5kV 20 MVA transformer with high and low side protection; new control building; land.

Sievers Rural load remains served at 34.5-kV.

Schedule: 2012-2015

Estimate: $2,250k (In 2014 $’s)

Wrap UpQuestions or Comments?

Thank YouContacts

Bob Easton (Western) 970-461-7272 or aeaston@wapa.gov

Roy Gearhart (Western) 970-461-7333 or rgearhar@wapa.gov

Stan Lawrenson (Tri-State) 303-254-3452 or slawrenson@tristategt.org