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Welcome to the TEP OASIS


Raquel Aguilar
OATT Services and
OASIS Administrator


24 Hour Contact
Real Time
Scheduling Desk


April 16, 2013

As part of the Vail to Valencia conversion project TEP is planning transmission outages which will require islanding portions of the Nogales AZ area to service by gas turbines. These outages will be individually posted on TEP's OASIS for the NOGTAP115-VALENCIA115 line and will occur between April 2013 and February 2014.

August 10, 2012

TEP has posted the TEP ATCID Version 2, Effective August 13, 2012. The document can be found in the ATC Information folder.

July 18, 2012

TEP has posted the TEP ATCID Version 1, Effective July 18, 2012. The document can be found in the ATC Information folder.

August 31, 2011

WECC auditors will be present in the TEPC's Control Room 8/31/2011.

August 5, 2011

Due to internal TEPC process revisions, there may be changes to real-time ATC values.

July 18, 2011

TEPC and UNSE have filed OATT revisions with FERC in order to implement and Hourly Firm Point-to-Point Transmission Service product. The Hourly Firm Transmission Service will be available for purchase on TEPC's OASIS as of 7/19/11 12:00am MST.

October 21, 2010

Due to the implementation of the NERC ATC-related MOD Standards, TTC (and therefore ATC) values posted for time periods after April 1, 2011 are under review and subject to change.

June 2, 2010

On June 1, 2010, the rating on the S. Navajo 500kV path was increased from 2264 MW to 2645 MW due to series capacitor upgrades. All participants have increased their TTC in OASIS to reflect the rating change.

May 26, 2010

On June 1, 2010, the rating on the S. Navajo 500kV Transmission path will be increased from 2264 MW to 2645 MW in the southbound direction. The rating increase is due to upgrades to the S. Navajo series capacitors. Participants of this line will appropriately adjust their individual TTC values no later than May 27th, 2010 to become effective on June 1, 2010.

June 5, 2009

Need Transmission with No Pancaked rates?

WestConnect members are making it easier for you to move your energy! Go to OASIS, click on the WC Wizard, enter the POR and POD and find the Hourly Non-firm transmission service available at the Regional Rate. Select the service you wish to buy and off you go.

Before you buy and use the Regional Transmission product, make sure you’ve done your homework…

— Have you executed the new, Non-Firm Annex A service agreement with all the WestConnect Pricing Experiment Regional TPs (AZPS, EPE, NEVP, PNM, PSCO, SWTC, TEPC, TSGT, WACM, & WALC)? The application and instructions can be found on the WestConnect website at

— Have you established creditworthiness with each Regional TP?

— Have you obtained the service through the OASIS/WC Wizard button?

— Have you followed proper E-Tagging procedures for all entities involved in the path?

A few things to remember along the way…

— Only Hourly, Non-Firm service is available with the Regional Rate.

— Sorry, but no renewals, resales, or redirects are allowed.

— All Regional TPs in the path have to approve the reservation before going to a CONFIRMED state…so be patient…

— You can only request the regional service through the WC Wizard interface on OASIS.

— Confirmed TSR will have a $.09/MWh administrative fee added on your bill, in addition to the cost of the transmission.

— Service starts soon. View the WC Wizard between June 9th and June 11th to acquaint yourself with the new OASIS tools.

*Losses and scheduling fees for each regional TP will still be charged.

May 29,2009

TEP has posted two new paths:



April 13, 2009

On March 30, 2009, TEPC filed a revision to its Attachment C with FERC. Please go to the "Filings Pending FERC Approval" subfolder (in the Tariff folder) to see a copy of the filing.

October 16, 2008

On October 15, 2008 the Palo Verde (PV)-Pinal West (PW) Project went into commercial operation. The participants of that project have posted this new path to their OASIS.

October 14, 2008

On October 15, 2008 the Palo Verde (PV)-Pinal West (PW) Project will be put into commercial operation. The PV-PW Project consists of a 500kV line that connects the Palo Verde area to the Pinal West Switchyard. The Pinal West Switchyard is located near Mobile, Arizona. The PV-PW Project has 6 Participants: Electrical District 2 (ED2), Electrical District 3 (ED3), Electrical District 4 (ED4), Salt River Project (SRP), Southwest Transmission Cooperative (SWTC) and Tucson Electric Power Company (TEP). The Total Transfer Capability (TTC) of the new line is 500 MW and will be split amongst the participants per their Ownership Interest. On October 15, 2008, no earlier than 0900 MST, the PV-PW Project Participants, will post the new path.

The PV-PW Project is part of the PV-East Cutset. The commercial operation of this line will have no impacts to current TTC on the Palo Verde Transmission System (PVTS) or the Southwest Valley Transmission Project (SWVP).

The following Business Practices have been posted on TEPC OASIS:

No Draft Business Practices at this Time

Draft Business Practices can be found in the "Draft Business Practices" for Comments folder within the "Business Practices" folder

TEPC will no longer accept offers for after-the-fact transmission sales. Thank you.

***See the News Section for instructions on tagging the WW5-PV5 segment when buying transmission from TEPC.***

**LOSSES Billing**

Beginning with December 2005 billing, TEPC will be charging for losses based on system incremental cost per hour, applied to schedules for that hour using the appropriate loss percentage from TEPC' OATT.

*Losses payback will be financial unless the Transmission Customer has made other arrangements with TEPC.


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