Request for Comment | Bulk Transmission Line Technical Requirements

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.