Bulk Transmission Line Technical Requirements

Purpose

The AESO is initiating a new engagement on Bulk Transmission Line Technical Requirements. Desired outcomes of this engagement include:

  1. Identifying cost-reduction opportunities for bulk transmission line projects;
  2. Providing enhanced clarity to stakeholders about the existing bulk transmission line technical requirements, with a goal of receiving fewer waiver and variance requests about the requirements; and
  3. Exploring and discussing recent changes in technology and standards relating to bulk transmission lines.

The AESO has developed the initial Issues List for stakeholders’ consideration and a series of Stakeholder Feedback Survey questions that will inform the AESO’s determination of the scope of the engagement. The AESO intends to host roundtable technical discussions during Q2 and Q3 of 2023 and invites interested stakeholders to participate. Given the subject matter of the engagement, the AESO envisions active participation from the following parties operating in Alberta:

  • transmission facility owners;
  • all types of industrial systems (i.e., not limited to industrial systems designated by the Alberta Utilities Commission) with transmission facilities;
  • generating facility owners who have built or are intending to build transmission facilities under the Market Participant Choice program; and
  • other parties who, in the AESO's view, are able to provide valuable input during the roundtable discussions.

To promote process efficiency, participation in the roundtable technical discussions will allow for one primary representative and one delegate. If both the primary and delegate representative are available, both representatives may attend the roundtable. The AESO will also provide periodic updates to participants not actively participating but who remain interested in the status of the engagement.

If, as a result of this engagement, the AESO determines that changes to AESO authoritative documents are required, these will be addressed through the applicable processes for developing ISO rules and Alberta reliability standards.

Background

Bulk Transmission Line Technical Requirements are primarily addressed in Section 502.2 of the ISO rules, Bulk Transmission Line Technical Requirements (“Section 502.2”). Section 502.2 has been in effect since January 1, 2012, to ensure a consistent approach to the design and operation of bulk transmission lines within Alberta. Section 502.2 addresses the minimum technical requirements in the areas of line design, construction, and operation to facilitate a fair, cost effective, and reliable transmission system.

In 2014, the AESO formed a technical working group (“TWG”) to review the minimum requirements for the design, construction and operation of bulk transmission lines. The TWG met multiple times between 2014 and 2018 to clarify requirements in Section 502.2 and explore opportunities to reduce transmission facility costs.

In 2019, the review of Section 502.2 was paused as a result of other AESO initiatives. Considering the amount of time that has elapsed since the initiation of the original TWG, the AESO is of the view that initiating a fresh engagement on bulk transmission line technical requirements would be more efficient than continuing with the prior consultation. Accordingly, the AESO has archived the prior consultation and is initiating this new engagement in Spring 2023.

Purpose

The AESO is initiating a new engagement on Bulk Transmission Line Technical Requirements. Desired outcomes of this engagement include:

  1. Identifying cost-reduction opportunities for bulk transmission line projects;
  2. Providing enhanced clarity to stakeholders about the existing bulk transmission line technical requirements, with a goal of receiving fewer waiver and variance requests about the requirements; and
  3. Exploring and discussing recent changes in technology and standards relating to bulk transmission lines.

The AESO has developed the initial Issues List for stakeholders’ consideration and a series of Stakeholder Feedback Survey questions that will inform the AESO’s determination of the scope of the engagement. The AESO intends to host roundtable technical discussions during Q2 and Q3 of 2023 and invites interested stakeholders to participate. Given the subject matter of the engagement, the AESO envisions active participation from the following parties operating in Alberta:

  • transmission facility owners;
  • all types of industrial systems (i.e., not limited to industrial systems designated by the Alberta Utilities Commission) with transmission facilities;
  • generating facility owners who have built or are intending to build transmission facilities under the Market Participant Choice program; and
  • other parties who, in the AESO's view, are able to provide valuable input during the roundtable discussions.

To promote process efficiency, participation in the roundtable technical discussions will allow for one primary representative and one delegate. If both the primary and delegate representative are available, both representatives may attend the roundtable. The AESO will also provide periodic updates to participants not actively participating but who remain interested in the status of the engagement.

If, as a result of this engagement, the AESO determines that changes to AESO authoritative documents are required, these will be addressed through the applicable processes for developing ISO rules and Alberta reliability standards.

Background

Bulk Transmission Line Technical Requirements are primarily addressed in Section 502.2 of the ISO rules, Bulk Transmission Line Technical Requirements (“Section 502.2”). Section 502.2 has been in effect since January 1, 2012, to ensure a consistent approach to the design and operation of bulk transmission lines within Alberta. Section 502.2 addresses the minimum technical requirements in the areas of line design, construction, and operation to facilitate a fair, cost effective, and reliable transmission system.

In 2014, the AESO formed a technical working group (“TWG”) to review the minimum requirements for the design, construction and operation of bulk transmission lines. The TWG met multiple times between 2014 and 2018 to clarify requirements in Section 502.2 and explore opportunities to reduce transmission facility costs.

In 2019, the review of Section 502.2 was paused as a result of other AESO initiatives. Considering the amount of time that has elapsed since the initiation of the original TWG, the AESO is of the view that initiating a fresh engagement on bulk transmission line technical requirements would be more efficient than continuing with the prior consultation. Accordingly, the AESO has archived the prior consultation and is initiating this new engagement in Spring 2023.

  • CLOSED: This survey has concluded.

    The AESO is seeking stakeholder input and feedback to inform the AESO’s determination of the scope of the engagement on bulk transmission line technical requirements. 

    Instructions 

    1. To submit your responses, you will need to be registered and signed in on the AESO Engage platform. 
    2. Please click on the "Submit Stakeholder Feedback" box below to begin the survey and provide your specific comments. 
    3. Please submit one completed survey per organization. 
    4. All responses will be shared on AESO Engage. 
    5. Responses are due on or before June 6, 2023. 

    Survey Questions for Stakeholders: 

    1. Return periods and exemptions: Should voltage level be the only driver for the level of reliability needed to determine the return period? 
    2. Weather maps: Should the AESO revise the weather loading maps to better account for probability of loading?
    3. Conductor selection: Should the AESO continue to only include aluminum conductor steel reinforced (ASCR) or be more inclusive of other conductor types?

      Conductor selection: Should the AESO review the criteria for triggering an optimization study?

    4. Basic design clearances: Should the AESO review the threshold for minimum sag conditions for 240 kV bulk transmission lines (no change to 500 kV)?

    5. Clearances to edge of right of way: Should the AESO add provisions to exempt 138/144 kV (or certain 240 kV) bulk transmission lines from horizontal clearance requirements so that they can be placed on road allowances?

    6. Clearances to edge of right of way: Should the AESO add details clarifying that horizontal clearance requirements can be reduced for areas where there are established building setbacks from the edges of property lines?

    7. Fall free spacing: Should voltage level be the only driver to determine the need for fall free spacing?

    8. Conductor thermal ratings methodology: Should the AESO review the prescribed parameters for calculating ampacity to allow alternative calculation methods for certain projects?

    9. Conductor thermal ratings methodology: Should the AESO allow special coatings (such as E3X coating) to be applied to existing conductors?

    10. Conductor emergency thermal ratings methodology: Should the AESO align its requirements for conductor emergency thermal ratings with Alberta Reliability Standard FAC-008, Facility Ratings (“FAC-008”)?

    11. Provision for live-line maintenance: Under what conditions is live-line maintenance required?

    12. Applicability of requirements: Is the 1.5 km length still relevant for determining the applicability of the AESO’s bulk transmission line technical requirements?

    13. Applicability of requirements: Should the determination be on a project-by-project basis?

    14. References to ASCE: Should the AESO review American Society of Civil Engineering Manual 74 –Guidelines for Electrical Transmission Line Structural Loading Third Edition and wind gust response factor values to ensure consistency?

    15. Overhead shieldwires: Should the AESO add a qualification that would allow bulk transmission line owners to use alternative and cost-effective forms of protection from lightning surges?

    16. Overhead shieldwires: Should the AESO review the minimum overhead shieldwire size?

    17. Clearances under differential loading – 138 kV exemption: Why is voltage the only driver for bulk transmission line reliability?

    18. Galloping: Under what conditions can interphase spacers be used? Are there other alternative methods for galloping control?

    19. Issues List: Do you have comments on the initial Issues List? If yes, please elaborate briefly.


    Submit Stakeholder Feedback
Page last updated: 13 Apr 2024, 10:09 PM