Western Oklahoma Transmission Reinforcement Project

    AEP Oklahoma Transmission Company, an affiliate of Public Service Company of Oklahoma (PSO), is planning significant improvements to the electric transmission system to ensure continued reliable power in western Oklahoma. The Western Oklahoma Transmission Reinforcement Project includes the following:

    • Building the new Chisholm substation
    • Constructing a new 345-kilovolt (kV) transmission line from west of Elk City to a point of interconnection with Oklahoma Gas & Electric Company (OG&E) near Mountain View.

    These investments are necessary to address system overloads and enhance long-term reliability in the region.


    The Company plans to construct the new Chisholm substation west of Elk City. In addition, approximately 60 miles of new 345 kV transmission line will be built starting at the new substation, and traveling east, connecting with a 345 kV transmission line out of OGE’s Gracemont Substation near Mountain View.


    To address existing system overloads identified by the Southwest Power Pool (SPP), a Regional Transmission Organization. SPP operates under federal mandate to ensure reliable supplies of power, adequate transmission infrastructure, and reasonable wholesale rates. Reinforcements in this area will enhance system reliability and support continuous growth in the region.


    The new substation will be located approximately 15 miles west of Elk City. The new transmission line will begin at the new substation and travel southeast toward Mountain View where it will connect with a planned 345 kV transmission line out of OGE's Gracemont Substation.

    Project Update

    Pre-construction activities are expected to begin in March beginning with staking of the rights-of-way and clearing vegetation and obstacles for construction. Crews will also install gates and culverts, as needed, along the rights-of-way for access during construction.

    Construction is expected to begin in early spring at the company’s new 345-kV Chisholm Substation west of Elk City.

    The construction of the line will begin Fall 2016 at the new substation then move east before turning southeast crossing Interstate-40 northeast of Sayre. The line continues southeast toward Sentinel before turning east and connecting with the portion of the line being built by Oklahoma Gas and Electric northwest of Mountain View. Construction on the 60-mile line is expected to be complete by summer of 2018.

    Project Benefits

    Reinforcements in this area will address system overloads and thereby enhance reliability and provide capacity for future growth in the region

    News Releases

    Fact Sheet


    Typical Structure


    Lesser Prairie-Chicken Conservation Plan

    * The accompanying map depicts the project area. It should be noted that the map contained on this site is for information purposes only. AEP reserves the right to alter, change, or amend the map at any time without notice and AEP provides no warranty about the accuracy of content. Keep this in mind when reviewing this map. However, AEP will make all attempts to keep this map as accurate as possible. If you have any questions about the accuracy of the current map please Contact Us.