Alberta Electric System Operator
Long Range Significant Transmission Outages for the period of 24 months starting 2025-01-11

The table below contains the significant transmission outages submitted as tentative to the AESO.
These Outages have not yet necessarily been approved, but are listed for awareness and coordination purposes.
An Outage has been considered significant for this table if it meets any one (1) or more of the following criteria:
  1. it affects a transmission facility operating at two hundred and forty (240) kV or greater;
  2. it affects an intertie;
  3. it affects an element connecting facilities owned by two (2) or more different legal owners of transmission facilities;
  4. it affects an element that connects a generating unit or an aggregated generating facility to the interconnected electric system;
  5. it requires the ISO to issue a dispatch or directive for generation in order to facilitate the planned outage;
  6. it affects a cutplane limit;
  7. it limits or reduces the operability of a synchronous condenser, static VAr compensator, static compensator or other similar dynamic device; or
  8. it affects high voltage direct current facilities.
Note: Where a transmission outage requires generation curtailments, the adjustments to generation will typically happen in the hours before the scheduled transmission outage and in the hour after the element is returned to service.

Previous Version
Download CSV

Owner From To Duration Element Scheduled Activity Affected Intertie
ALTALINK 27-Aug-24 10:00 31-Jan-25 12:00 157.13 Days
Continuous		 244s 17 (244s Bowmanton) construction of new cap C1.  
ALTALINK 27-Aug-24 10:00 31-Jan-25 12:00 157.13 Days
Continuous		 244s 25 (244s Bowmanton) construction of new cap C2.  
ALTALINK 27-Aug-24 10:00 31-Jan-25 12:00 157.13 Days
Continuous		 244s 24 (244s Bowmanton) construction of new cap C3  
ATCO, ALTALINK 04-Oct-24 01:05 05-May-25 12:00 213.45 Days
Continuous		 840s McNeill Station, 830L (562s Cypress - 840s McNeill Station), 840s 701T (840s McNeill Station), 840s 901T (840s McNeill Station), 840s 702C (840s McNeill Station), 840s 703C (840s McNeill Station) forced outage AB-SK
BHE Canada 05-Oct-24 00:00 30-Apr-25 17:00 207.71 Days
Continuous		 120s C1 (120s Picture Butte) forced outage  
ATCO, ALTALINK 15-Oct-24 11:00 15-Jan-25 12:00 92.08 Days
Continuous		 840s McNeill Station, 830L (562s Cypress - 840s McNeill Station), 840s 701T (840s McNeill Station), 840s 901T (840s McNeill Station), 840s 901 (840s McNeill Station), 840s 701 (840s McNeill Station), 840s 702C (840s McNeill Station), 840s 703C (840s McNeill Station) transformer 701T and 901T bushing replacements and annual maintenance AB-SK
ATCO 06-Jan-25 10:00 13-Jan-25 08:00 6.92 Days
Continuous		 7L40 (733s Simonette - 813s Little Smoky) Changing rotten X Arms and rotten poles from Test and Treat  
ATCO 11-Jan-25 09:00 12-Jan-25 17:00 1.33 Days
Continuous		 801s 705 (801s Anderson), 7L85 (801s Anderson - ATC 803s Bullpound) DFR Upgrade at Anderson.
Demo inputs from existing DSM: 705CT, 21A/7L85 and 21B/7L85 DSM trigger, 94-700BS1 trigger (requires blocking of 87BA/700BS1 during wire removal), and 700PT1Y1 input (requires blocking during wire removal).
7L85 relay setting updates.		  
EPCOR 13-Jan-25 07:00 14-Mar-25 17:00 60.38 Days
Continuous		 987s T2 (987s Clover Bar), 987s CDS45 (987s Cloverbar) Cloverbar S/S TX2 and 1191L Bay outage  
BCH 13-Jan-25 08:00 24-Jan-25 16:00 11.33 Days
Continuous		 T3 (BCH Natal) NTL Station Rebuild. T3 OOS for PN replacement AB-BC
ATCO 13-Jan-25 10:00 20-Jan-25 08:00 6.92 Days
Continuous		 7L32 (811s Clairmont Lake - 862s South Bezanson) Changing rotten X Arms and rotten poles from Test and Treat  
ENMAX, ALTALINK 20-Jan-25 08:00 23-Jan-25 16:00 3.33 Days
Continuous		 918L (281s Johnson - SS-162) 162 Substation -Surge Arrester Addition  
ATCO, ALTALINK 20-Jan-25 10:00 23-Jan-25 16:30 3.27 Days
Continuous		 7L129 (526s Buffalo Creek - 7LA129 tap) Replace structures, cross arms and insulators on 7L129  
ATCO, ALTALINK 20-Jan-25 10:00 23-Jan-25 16:30 3.27 Days
Continuous		 7L129 (526s Buffalo Creek - 7LA129 tap) Replace structures, cross arms and insulators on 7L129  
ATCO 20-Jan-25 10:00 24-Jan-25 12:00 4.08 Days
Continuous		 741s 701T (741s Fox Creek), 741s 701 (741s ATC Fox Creek), 741s 702 (741s ATC Fox Creek), 741s 702T (741s Fox Creek), 741s 703 (741s ATC Fox Creek), 741s 704 (741s ATC Fox Creek), 741s 705C (741s Fox Creek), 741s 705 (741s ATC Fox Creek), 7L90 (741s ATC Fox Creek - 7LA90 tap), 7L199 (347s AML Fox Creek - 741s ATC Fox Creek) Install new 144kV PT to 144kV bus in a new location.  
ALTALINK 20-Jan-25 12:00 21-Jan-25 18:00 30 Hours
Continuous		 190L (17s Benalto - 320p Keephills) Component replacement on 190L (STR24-417)  
ATCO 21-Jan-25 09:00 26-Jan-25 16:00 5.29 Days
Continuous		 9L10 (876s Brintnell - 939s Livock) Line to Ground Mitigation  
ATCO 24-Jan-25 09:00 24-Jan-25 16:00 7 Hours
Continuous		 7L50 (757s Battle River - 491L tap) 7L50 Pole Replacement Structure 214  
SUNCOR 27-Jan-25 08:00 02-Feb-25 20:00 6.5 Days
Continuous		 29EDD-34 29PT-341 (29EDD-34) BP (Corey) - 29EDD34;29PT-341 SYSTEM;PM 10y; 29EDD34;29PP-103 SYSTEM;PM 5y,10y
  
ATCO, ALTALINK 27-Jan-25 10:00 31-Jan-25 16:30 4.27 Days
Continuous		 7L129 (526s Buffalo Creek - 7LA129 tap) Replace structures, cross arms and insulators on 7L129  
ATCO, ALTALINK 27-Jan-25 10:00 31-Jan-25 16:30 4.27 Days
Continuous		 7L129 (526s Buffalo Creek - 7LA129 tap) Replace structures, cross arms and insulators on 7L129  
ATCO 27-Jan-25 10:00 03-Feb-25 08:00 6.92 Days
Continuous		 7L32 (813s Little Smoky - 862s South Bezanson) Changing rotten X Arms and rotten poles from Test and Treat  
ALTALINK 27-Jan-25 12:30 31-Jan-25 17:30 4.21 Days
Continuous		 190L (17s Benalto - 320p Keephills) Component replacement on 190L (STR24-417)  
ALTALINK, BCH 29-Jan-25 08:00 29-Jan-25 16:00 8 Hours
Continuous		 1L274 (BCH Natal - BCH Line Creek tap), 1CB1 (BCH Natal) NTL 1CB1 Ras testing AB-BC
ENMAX 29-Jan-25 10:00 30-Jan-25 16:00 30 Hours
Continuous		 240kV West Bus (SS-25) Altalink outage. Bus outage required due to clearance under 240kV lower West bus to deliver cables. AltaLink will work under Enmax permit – Grounding required, Submit SRF.  
BCH 30-Jan-25 08:00 30-Jan-25 16:00 8 Hours
Continuous		 1L275 (799s Coleman - BCH Natal), 1CB2 (BCH Natal) NTL 1CB2 Ras testing AB-BC
ATCO 30-Jan-25 10:00 30-Jan-25 17:00 7 Hours
Continuous		 801s 910 (801s Anderson) Final connection of Bkr 910 52a single pole status inputs to DFR, Commission  
SUNCOR 03-Feb-25 08:00 09-Feb-25 20:00 6.5 Days
Continuous		 29EDD-34 29PT-340 (29EDD-34) 29EDD34;29PT-340 SYSTEM;PM 5y,10y; 29EDD34;29PP-102 SYSTEM;PM 5y,10y
  
ATCO 03-Feb-25 09:00 10-Feb-25 16:00 7.29 Days
Continuous		 9L10 (876s Brintnell - 939s Livock) Line to Ground Mitigation  
ALTALINK 03-Feb-25 12:00 07-Feb-25 18:00 4.25 Days
Continuous		 190L (17s Benalto - 320p Keephills) Component replacement on 190L (STR24-417)  
ATCO 04-Feb-25 10:00 07-Feb-25 15:30 3.23 Days
Continuous		 848s 902T (848s Ruth Lake) Replace Breaker 401.
Clearance under/around the bus on 902T is required for 401 placement.		  
ATCO 08-Feb-25 08:00 11-Feb-25 17:00 3.38 Days
Continuous		 7L85 (804s Wintering Hills - 7LA85 tap) Install interphase spacers  
ENMAX 10-Feb-25 08:00 11-Feb-25 16:00 1.33 Days
Continuous		 162B138-RB80 (SS-162), 162B138-RB81 (SS-162), 162.81L (391s Balzac - SS-162) HV SW Maint. 162SW82, 162SW83, MD-162.81L  
ALTALINK 10-Feb-25 08:00 11-Feb-25 16:30 1.35 Days
Continuous		 391s 162.81 (391s Balzac) HV SW Maint. 162SW82, 162SW83, MD-162.81L.  
ATCO 10-Feb-25 10:00 14-Feb-25 17:00 4.29 Days
Continuous		 9L16 (755s Cordel - 972s Tinchebray) Install foundations for new 9L16 structures 73 and 74 in preparation of the future line bay re-termination into 972S Tinchebray expansion.  
ATCO 10-Feb-25 10:00 17-Feb-25 08:00 6.92 Days
Continuous		 7L32 (811s Clairmont Lake - 862s South Bezanson) Changing rotten X Arms and rotten poles from Test and Treat  
ALTALINK 10-Feb-25 12:00 14-Feb-25 18:00 4.25 Days
Continuous		 903L (17s Benalto - 320p Keephills) Structure replacement at 903L24  
ENMAX, ALTALINK 11-Feb-25 09:00 21-Feb-25 17:00 10.33 Days
Continuous		 1109L (SS-25 - SS-65) 25s 240kV West Bus and 1109L outage required due to clearances while placing new cables onto strs (1109L STR1 and C25s).  
ENMAX, ALTALINK 11-Feb-25 09:00 21-Feb-25 17:00 10.33 Days
Continuous		 240kV West Bus (SS-25), 1109L (SS-25 - SS-65) Altalink outage. 25s 240kV West Bus and 1109L outage required due to clearances while placing new cables onto strs (1109L STR1 and C25s). Enmax to install grounds at 25s.  
ENMAX, ALTALINK 12-Feb-25 08:00 13-Feb-25 16:00 1.33 Days
Continuous		 162B240-RB133 (SS-162), 918L (281s Johnson - SS-162), 162B240-RB132 (SS-162) HV SW Maint. 162SW135, 162SW134. MD-918L  
ENMAX, ALTALINK 12-Feb-25 08:00 13-Feb-25 16:30 1.35 Days
Continuous		 918L (281s Johnson - SS-162) HV SW Maint. 162SW135, 162SW134. MD-918L  
ATCO 17-Feb-25 09:00 24-Feb-25 16:00 7.29 Days
Continuous		 9L10 (876s Brintnell - 939s Livock) Line to Ground Mitigation  
ATCO 17-Feb-25 12:01 03-Mar-25 12:00 14 Days
Continuous		 7L199 (347s AML Fox Creek - 741s ATC Fox Creek), 741s 702 (741s ATC Fox Creek) Fox Creek Substation Upgrade project. Demo old cables, install and terminate new cables, cut over to new protection.
  
ALTALINK 17-Feb-25 12:01 03-Mar-25 12:30 14.02 Days
Continuous		 199L (347s AML Fox Creek - 741s ATC Fox Creek) Fox Creek Substation Upgrade project. Demo old cables, install and terminate new cables, cut over to new protection.  
ATCO 18-Feb-25 08:00 23-Feb-25 17:00 5.38 Days
Continuous		 7L85 (803s ATC Bullpound - 7LA85 tap) Install interphase spacers  
ATCO, ALTALINK 20-Feb-25 10:00 20-Feb-25 12:00 2 Hours
Continuous		 7L77 (395s North Holden - 709s Vegreville), 709s 704 (709s Vegreville) PRC-005 TRIP COIL TESTING BREAKER 704  
ALTALINK, TRANSALTA 22-Feb-25 08:00 22-Feb-25 17:00 9 Hours
Daily		 33s T2 (33s Spray) Spray Unit #2 Brushgear Maintenance.  
ATCO 24-Feb-25 07:00 13-Mar-25 17:00 17.38 Days
Continuous		 730s 701T (730s Rycroft) install new relays, new 2z panel, end to end testing.  
ATCO 24-Feb-25 08:00 25-Feb-25 17:00 1.38 Days
Continuous		 7L85 (801s Anderson - ATC 803s Bullpound) Crossarm Replacements, install interphase spacers, clearance mitigation  
ENMAX 24-Feb-25 08:00 28-Feb-25 16:00 4.33 Days
Continuous		 162.1TR (SS-162), 240kV North Bus (SS-162), 138kV North Bus (SS-162) HV SW Maint. 162SW110, 162SW96, 162SW81, 162SW131, 162SW141, MD13-162.1TR, MD240-162.1TR  
ENMAX, ALTALINK 24-Feb-25 08:00 14-Mar-25 16:00 18.29 Days
Continuous		 20.82L (SS-20 - SS-21), 21.80L (42s Sarcee - SS-21), 21.1TR (SS-21) HV SW Replacement 21SW81, 21SW82, 21SW83, 21MD138-21.1TR, 21.4TR (SS-21)  
ENMAX, ALTALINK 24-Feb-25 08:00 14-Mar-25 16:00 18.29 Days
Continuous		 21.80L (42s Sarcee - SS-21) HV SW Replacement 21SW81, 21SW82, 21SW83, 21MD138-21.1TR, 21.4TR (SS-21)  
BCH 24-Feb-25 09:00 28-Feb-25 17:00 4.33 Days
Continuous		 5L51 (BPA Custer - BCH Ingledow) ING 5CB3 Insp and doble AB-BC
ATCO 24-Feb-25 10:00 03-Mar-25 16:00 7.25 Days
Continuous		 7L32 (811s Clairmont Lake - 862s South Bezanson) Changing rotten X Arms and rotten poles from Test and Treat  
ATCO 27-Feb-25 12:00 27-Feb-25 16:00 4 Hours
Continuous		 7L146 (700s Bonnyville - 970s Bourque), 700s 704 (700s Bonnyville) PRC-005 TRIP COIL TESTING  
ENMAX 03-Mar-25 08:00 07-Mar-25 16:00 4.33 Days
Continuous		 162.2TR (SS-162), 138kV South Bus (SS-162), 240kV South Bus (SS-162) HV SW Maint. 162SW88, 162SW89, 162SW105, 162SW136, 162SW146, MD138-162.2TR, MD240-162.2TR  
ATCO 03-Mar-25 09:00 10-Mar-25 16:00 7.25 Days
Continuous		 9L10 (876s Brintnell - 939s Livock) Line to Ground Mitigation  
ATCO, ALTALINK 03-Mar-25 10:00 07-Mar-25 16:30 4.27 Days
Continuous		 7L129 (526s Buffalo Creek - 7LA129 tap) Replace structures, cross arms and insulators on 7L129  
ATCO, ALTALINK 03-Mar-25 10:00 07-Mar-25 16:30 4.27 Days
Continuous		 7L129 (526s Buffalo Creek - 7LA129 tap) Replace structures, cross arms and insulators on 7L129  
ALTALINK 04-Mar-25 07:00 05-Mar-25 18:00 1.46 Days
Continuous		 892L (244s Bowmanton - 895s Suffield) Cutover, test LTO, CT circuits at 244s and 895s to new RAS209 relays. Trip test 895s892 from new ‘B’ Bus protection and Breaker Fail relay. New maintenance switch being installed for breaker 244s2952 and 244s3052.  
ATCO 04-Mar-25 08:00 11-Mar-25 17:00 7.33 Days
Continuous		 7L85 (801s Anderson - ATC 803s Bullpound) Crossarm Replacements, install interphase spacers, clearance mitigation  
ALTALINK 06-Mar-25 07:00 06-Mar-25 18:00 11 Hours
Daily		 100L (498s Tilley - 895s Suffield) Remove old 96 CT circuits. Add 138kV Bus protection CT circuit.  
ATCO 06-Mar-25 12:00 06-Mar-25 16:00 4 Hours
Continuous		 7L24 (700s Bonnyville - 7LA24 tap), 700s 708 (700s Bonnyville) PRC-005 TRIP COIL TESTING  
ALTALINK 10-Mar-25 08:00 10-Mar-25 16:00 8 Hours
Daily		 336s 612 (336s Fincastle), 612L (336s Fincastle - 368s Burdett) Breaker outage to add CT circuit to new PMU  
ENMAX, ALTALINK 10-Mar-25 08:00 11-Mar-25 16:00 1.33 Days
Continuous		 932L (74s Janet - SS-162) HV SW Maint. 162SW145, 162SW144, MD-932L  
ATCO 10-Mar-25 08:00 13-Mar-25 17:00 3.38 Days
Continuous		 7L28 (717s Ethel Lake - 846s Grand Centre) 7L28 Line to ground clearance mitigation  
ATCO 10-Mar-25 10:00 17-Mar-25 16:00 7.25 Days
Continuous		 7L32 (811s Clairmont Lake - 862s South Bezanson) Changing rotten X Arms and rotten poles from Test and Treat  
ATCO 10-Mar-25 10:00 17-Mar-25 17:00 7.29 Days
Continuous		 9L40 (732s Mitsue - 809s Louise Creek) change out several Orange tagged/ damaged poles.  
ALTALINK 11-Mar-25 08:00 11-Mar-25 16:00 8 Hours
Daily		 336s 607 (336s Fincastle), 607L (336s Fincastle - 607AL tap), 607L (135s Conrad - 607AL tap), 135s T1 (135s Conrad), 135s T2 (135s Conrad) Breaker outage to add CT circuit to new PMU  
ALTALINK 12-Mar-25 07:00 12-Mar-25 17:00 10 Hours
Daily		 83s 138kV East Bus (83s Taber), 83s T3 (83s Taber), 83s 64 (83s Taber), 83s C1 (83s Taber), 83s 507 (83s Taber), 507L (83s Taber - 257s Hull), 83s 61 (83s Taber) Bus outage to trip test 83s507 (852), 83s61 (1152) and 83s64 (395) from new 83s610 (152) breaker fail protection.  
EPCOR 17-Mar-25 07:00 21-Mar-25 17:00 4.42 Days
Continuous		 987s T2 (987s Clover Bar), 987s C2410 (987s Clover Bar), 987s C2406 (987s Clover Bar), 987s CC721 (987s Clover Bar) Cloverbar: TX2 VRR Cut Overs  
ALTALINK 17-Mar-25 07:00 28-Mar-25 18:00 11.46 Days
Continuous		 610L (83s Taber - 336s Fincastle) VATD - Rebuild 610L. Cut over from Old 610L to New 610L. Replace 610L protections and add breaker fail protection.  
ENMAX, ALTALINK 17-Mar-25 08:00 27-Mar-25 16:00 10.33 Days
Continuous		 50L (44s Bearspaw Plant - SS-21) HV SW Replacement 21SW87, 21SW88, 21SW89, 21MD138-21.2TR  
ENMAX, ALTALINK 17-Mar-25 08:00 27-Mar-25 16:00 10.33 Days
Continuous		 50L (44s Bearspaw Plant - SS-21), 21.1C (SS-21), 21.2TR (SS-21) HV SW Replacement 21SW87, 21SW88, 21SW89, 21MD138-21.2TR  
ATCO 18-Mar-25 08:00 19-Mar-25 17:00 1.38 Days
Continuous		 7L53 (706s Irish Creek - 7LA53 tap), 7LA53 (969s Lindbergh - 7L53 tap), 7L53 (700s Bonnyville - 7LA53 tap) Cold Lake Area Project to connect 1064s  
ATCO 18-Mar-25 08:00 25-Mar-25 17:00 7.38 Days
Continuous		 7L85 (801s Anderson - ATC 803s Bullpound) Crossarm Replacements, install interphase spacers, clearance mitigation  
ALTALINK 19-Mar-25 07:00 20-Mar-25 18:00 1.46 Days
Continuous		 83s T1 (83s Taber), 83s 65 (83s Taber), 83s 610 (83s Taber), 610L (83s Taber - 336s Fincastle), 83s 172W (83s Taber), 172L (83s Taber - 172EL tap), 83s 67 (83s Taber), 83s C2 (83s Taber) Bus outage to trip test 83s172w, 83s67, 83s65, 83s610  
ENMAX, ALTALINK 22-Mar-25 08:00 23-Mar-25 16:00 1.33 Days
Continuous		 771L (SS-47 - SS-162), 162B138-RB82 (SS-162), 47.1TR (SS-47), 47.2TR (SS-47), 162B138-RB81 (SS-162) HV SW Maint. 162SW85, 162SW84, MD-771L  
ATCO 24-Mar-25 08:00 27-Mar-25 17:00 3.38 Days
Continuous		 7L91 (715s Leming Lake - 826s Marguerite Lake) Cold Lake Area Energy Centre Project
Cutover CT/PT/P&C ccts for new Thermal RAS relays
Complete commissioning 49A/49B/7L91 relays
End-to-end testing to 1064S		  
ATCO 24-Mar-25 10:00 27-Mar-25 16:00 3.25 Days
Continuous		 7L89 (700s Bonnyville - 721s La Corey), 700s 703 (700s Bonnyville) PRC-005 RELAY TESTING, RTXP TEST SWITCH REPLACEMENTS, PRC-005 TRIP COIL TESTING  
ATCO 24-Mar-25 10:00 31-Mar-25 16:00 7.25 Days
Continuous		 7L32 (811s Clairmont Lake - 862s South Bezanson) Changing rotten X Arms and rotten poles from Test and Treat  
ENMAX, ALTALINK 24-Mar-25 11:30 25-Mar-25 17:00 29.5 Hours
Continuous		 693L (42s Sarcee - SS-10) 693L U/G cables seal flooded vaults from water ingress.  
ENMAX, ALTALINK 24-Mar-25 11:30 25-Mar-25 17:00 29.5 Hours
Continuous		 693L (42s Sarcee - SS-10) Altalink outage. 693L U/G cables seal flooded vaults from water ingress  
ALTALINK 26-Mar-25 11:00 27-Mar-25 17:30 30.5 Hours
Continuous		 916L (5s East Calgary - 42s Sarcee) 916L U/G cables seal flooded vaults from water ingress.  
ENMAX 29-Mar-25 09:00 06-May-25 14:00 38.21 Days
Continuous		 240kV West Bus (SS-25) Altalink outage. Scaffold and Begin to Terminate new Cables at C25s. AltaLink to work under Enmax permit – Grounding required. Submit SRF.  
ALTALINK 31-Mar-25 06:00 04-Apr-25 18:00 4.5 Days
Continuous		 879L (244s Bowmanton - 879AL tap), 879L (368s Burdett - 879L tap) Replace structures 719-723.  
ATCO 31-Mar-25 09:00 09-Apr-25 17:00 9.33 Days
Continuous		 7L701 (757s Battle River - 7LA701 tap), 757s 707 (757s Battle River) replace overhead shield wire with OPGW cable on 7L701 from structure 1 to 11  
ATCO 31-Mar-25 14:00 28-Apr-25 11:00 27.88 Days
Continuous		 732s 902T (732s Mitsue) Protection upgrade. Remove old protection, cut over to new protection and cut over equipment status, control and alarms to new station controller.  
SUNCOR 07-Apr-25 08:00 13-Apr-25 20:00 6.5 Days
Continuous		 29EDD-56 29PT-190 (29EDD-56) 29EDD-56;29PT-190 SYSTEM;PM 5y; 29EDD56;29PP-41H SYSTEM;PM 5Y/10Y  
ATCO 07-Apr-25 10:00 14-Apr-25 16:00 7.25 Days
Continuous		 7L32 (811s Clairmont Lake - 862s South Bezanson) Changing rotten X Arms and rotten poles from Test and Treat  
SUNCOR 14-Apr-25 08:00 20-Apr-25 20:00 6.5 Days
Continuous		 29EDD-56 29PT-191 (29EDD-56) 29EDD56;29PT-191 SYSTEM;PM 5Y/10Y;29EDD56;29PP-41C SYSTEM;PM 5y  
ENMAX 17-Apr-25 08:00 22-Apr-25 16:00 5.33 Days
Continuous		 2GSU-XF-001 (SS-25) Power Factor Test - 25PT240-Z44, 25BUS240-25MCT2, 25 Sub Zone 44 PT Oil Leaks (North and South PT)  
ENMAX 17-Apr-25 08:00 25-Apr-25 16:00 8.33 Days
Continuous		 65.1TR (SS-65) Tap Changer Inspection  
ATCO 21-Apr-25 08:00 24-Apr-25 17:00 3.38 Days
Continuous		 7L86 (822s Wolf Lake - 1200s Foster Creek) Cenovus is expanding their 1200S substation 26m to the south, toward structure 449.
We will be relocating the conductor north of structure 449 to the new A-Frame structure that Cenovus is installing inside their substation.		  
ATCO 22-Apr-25 10:00 28-Apr-25 16:00 6.25 Days
Continuous		 7L32 (811s Clairmont Lake - 862s South Bezanson) Changing rotten X Arms and rotten poles from Test and Treat  
ENMAX, ALTALINK 25-Apr-25 08:00 28-Apr-25 16:00 3.33 Days
Continuous		 20.82L (SS-20 - SS-21), 21.80L (42s Sarcee - SS-21), 21.1TR (SS-21), 50L (44s Bearspaw Plant - SS-21), 21.1C (SS-21), 21.2TR (SS-21) HV SW Replacement 21SW86. Full substation outage  
ALTALINK, ENMAX 25-Apr-25 08:00 28-Apr-25 16:00 3.33 Days
Continuous		 42s 22 (42s Sarcee), 21.80L (42s Sarcee - SS-21) HV SW Replacement 21SW86. Full substation outage  
ENMAX, ALTALINK 25-Apr-25 08:00 28-Apr-25 16:00 3.33 Days
Continuous		 50L (44s Bearspaw Plant - SS-21) HV SW Replacement 21SW86. Full substation outage  
ATCO 28-Apr-25 10:00 01-May-25 14:00 3.17 Days
Continuous		 7L66 (715s Leming Lake - 717s Ethel Lake) GOI needed for climbing inspection and deficiency repairs on 7L66  
ATCO, ALBIAN 02-May-25 08:00 13-May-25 08:00 11 Days
Continuous		 919s 906 (919s Hartley) CNRL Request to isolate 906  
SUNCOR 03-May-25 09:00 15-May-25 16:00 12.29 Days
Continuous		 29EDD-1 T2 (29EDD-1 Millennium) BP-29EDD-1 - TA - T2 OLTC Maintenance and Testing; 29EDD-1 T2 72LV Arrester replacement (CG)
300199837, 300203566		  
ATCO 05-May-25 09:00 06-May-25 15:00 30 Hours
Continuous		 755s 901 (755s Cordel) BREAKER 901 SF6 GL315 COMPLETE TESTING @ 755S Cordel  
ATCO 05-May-25 10:00 08-May-25 16:00 3.25 Days
Continuous		 7L89 (700s Bonnyville - 721s La Corey) GOI required for climbing inspection on 7L89 and for deficiency repair.  
ENMAX, ALTALINK 06-May-25 14:00 12-May-25 14:00 6 Days
Continuous		 1109L (SS-25 - SS-65) Scaffold and begin to Terminate new Cables on 1109L str 1.  
ENMAX, ALTALINK 06-May-25 14:00 12-May-25 14:00 6 Days
Continuous		 240kV West Bus (SS-25), 1109L (SS-25 - SS-65) Altalink outage. 25s Scaffold and begin to Terminate new Cables on 1109L. Expanding zone to include 1109L, Enmax grounds to stay on.  
ATCO 07-May-25 09:00 08-May-25 15:00 30 Hours
Continuous		 755s 902 (755s Cordel) BREAKER 902 SF6 GL315 COMPLETE TESTING @ 755S Cordel  
ATCO 12-May-25 10:00 15-May-25 16:00 3.25 Days
Continuous		 7L89 (700s Bonnyville - 721s La Corey) GOI required for climbing inspection on 7L89 and for deficiency repair.  
ENMAX, ALTALINK 12-May-25 14:00 31-May-25 14:00 19 Days
Continuous		 1109L (SS-25 - SS-65) Complete Termination of new Cables on 1109L str 1.  
ENMAX, ALTALINK 12-May-25 14:00 31-May-25 14:00 19 Days
Continuous		 1109L (SS-25 - SS-65) Altalink outage. Complete Termination of new Cables on 1109L str 1.  
ATCO 12-May-25 14:00 09-Jun-25 11:00 27.88 Days
Continuous		 732s 901T (732s Mitsue), 732s 701 (732s Mitsue), 732s 702 (732s Mitsue), 732s 902 (732s Mitsue), 732s 903 (732s Mitsue) Protection upgrade. Remove old protection, cut over to new protection and cut over equipment status, control and alarms to new station controller.  
SUNCOR 18-May-25 07:00 21-May-25 17:00 3.42 Days
Continuous		 635EDD-1000 144kV Bus 635PP-1000 (635EDD-1000), 635EDD-1000 635PT-1000 (635EDD-1000), 635EDD-1000 635PS-1002 (635EDD-1000), 635EDD-1000 635PS-1004 (635EDD-1000), 635EDD-1000 635PS-1010 (635EDD-1000), 635EDD-1000 635PS-1022 (635EDD-1000), 635EDD-1000 635PS-1026 (635EDD-1000), 635EDD-1000 635PS-1030 (635EDD-1000), 635EDD-1000 635PS-1016 (635EDD-1000), 635EDD-1000 635-752-635PT-1000 (635EDD-1000) 635PP-1000 bus maintenance  
ATCO 20-May-25 10:00 22-May-25 16:00 2.25 Days
Continuous		 7L89 (721s La Corey - 826s Marguerite Lake) GOI required for climbing inspection on 7L89 and for deficiency repair.  
SUNCOR 25-May-25 07:00 28-May-25 17:00 3.42 Days
Continuous		 635EDD-1000 144kV Bus 635PP-1001 (635EDD-1000), 635EDD-1000 635PT-1001 (635EDD-1000), 635EDD-1000 635-752-635PT-1001 (635EDD-1000), 635EDD-1000 635PS-1003 (635EDD-1000), 635EDD-1000 635PS-1009 (635EDD-1000), 635EDD-1000 635PS-1015 (635EDD-1000), 635EDD-1000 635PS-1021 (635EDD-1000), 635EDD-1000 635PS-1025 (635EDD-1000), 635EDD-1000 635PS-1029 (635EDD-1000), 635EDD-1000 635PS-1035 (635EDD-1000) 635PP-1001 bus maintenance  
ATCO 26-May-25 10:00 29-May-25 16:00 3.25 Days
Continuous		 7L91 (715s Leming Lake - 826s Marguerite Lake) GOI required for climbing inspection on 7L91 and for deficiency repair.  
ATCO 27-May-25 08:00 03-Jun-25 17:00 7.38 Days
Continuous		 7L224 (650s Hansman Lake - 774s Monitor) Install interphase spacers on 7L224  
ENMAX, ALTALINK 31-May-25 14:00 02-Jun-25 14:00 2 Days
Continuous		 1109L (SS-25 - SS-65) Cable testing, close cable open points on 1109L and salvage Temp O/H 1109L  
ENMAX, ALTALINK 31-May-25 14:00 02-Jun-25 14:00 2 Days
Continuous		 240kV West Bus (SS-25), 1109L (SS-25 - SS-65) Altalink outage. Cable testing, close cable open points on 1109L and salvage Temp O/H 1109L. Expanding zone to include 1109L C25s Bus. Enmax grounding required, and Enmax to close 1109L risers removed from bus to potthead.  
ATCO 02-Jun-25 12:00 06-Jun-25 16:00 4.17 Days
Continuous		 826s 901T (826s Marguerite Lake) transformer major maintenance  
SUNCOR 06-Jun-25 00:00 22-Jun-25 00:00 16 Days
Continuous		 29PL7-4 (29EDD-65 - 29EDD-71), 29EDD-65 29PS-0284 (29EDD-65 Edd65Sub), 29EDD-71 29PS-243 (29EDD-71 Edd71Sub), 29EDD-65 29PT-0257 (29EDD-65) FB-Maintenance and Testing - 29PT-260, 29PL7-4, 29PT-241, 29PT-257, 29PS-243 (450236799, 450233735, 31773784, 450237159)  
ATCO 09-Jun-25 09:00 23-Jun-25 17:30 14.35 Days
Continuous		 2029S BUILDING VALVE HALL, 2029s 1205 (2029s Heathfield), 2029s 1206 (2029s Heathfield) Annual EATL outage at 2075s & 2029s.

2029s & 2075s AC & DC O&M.

USE 2-70215 FOR 13L50 GOI
USE 2-70216 FOR 2029s GOI
USE 2-70217 FOR 2075s GOI		  
ATCO 09-Jun-25 09:00 23-Jun-25 17:30 14.35 Days
Continuous		 2075S BUILDING VALVE HALL, 2075s 916 (2075s Newell), 2075s 917 (2075s Newell) Annual EATL outage at 2075s & 2029s.

2029s & 2075s AC & DC O&M.

USE 2-70215 FOR 13L50 GOI
USE 2-70216 FOR 2029s GOI
USE 2-70217 FOR 2075s GOI		  
ATCO 09-Jun-25 09:00 23-Jun-25 17:30 14.35 Days
Continuous		 13L50 (DC LINK), 13L50 (2029s Heathfield - 2075s Newell) Annual EATL outage at 2075s & 2029s.

2029s & 2075s AC & DC O&M.

USE 2-70215 FOR 13L50 GOI
USE 2-70216 FOR 2029s GOI
USE 2-70217 FOR 2075s GOI		  
ATCO 09-Jun-25 12:00 13-Jun-25 16:00 4.17 Days
Continuous		 826s 902T (826s Marguerite Lake) transformer major maintenance  
ENMAX, ALTALINK 16-Jun-25 08:00 19-Jun-25 16:00 3.33 Days
Continuous		 28.80L (42s Sarcee - SS-28) HV SW Replacement. 28SW80  
ENMAX, ALTALINK 16-Jun-25 08:00 19-Jun-25 16:00 3.33 Days
Continuous		 28.80L (42s Sarcee - SS-28) HV SW Replacement 28SW80  
ATCO 23-Jun-25 14:00 07-Jul-25 11:00 13.88 Days
Continuous		 9L40 (732s Mitsue - 809s Louise Creek), 732s 901 (732s Mitsue), 732s 902 (732s Mitsue) Protection upgrade. Remove old protection, cut over to new protection and cut over equipment status, control and alarms to new station controller.  
ENMAX, ALTALINK 27-Jun-25 08:00 03-Jul-25 16:00 6.33 Days
Continuous		 37.2TR (SS-37), 37.82L (74s Janet - SS-37) HV SW Replacement. 37SW84, 37SW85, 37SW86  
ENMAX, ALTALINK 27-Jun-25 08:00 03-Jul-25 16:00 6.33 Days
Continuous		 50L (44s Bearspaw Plant - SS-21) HV SW Replacement. 37SW84, 37SW85, 37SW86  
SUNCOR 01-Jul-25 00:00 18-Jul-25 00:00 17 Days
Continuous		 29PL7-3 (29EDD-65 - 29EDD-71), 29EDD-65 29PT-0236 (29EDD-65) FB-Maintenance and Testing - 29PT-250, 29PL7-3, 29PT-246, 29PT-236 (450237140, 450237180, 450237158)  
ATCO 07-Jul-25 14:00 21-Jul-25 11:00 13.88 Days
Continuous		 9L913 (69s North Barrhead - 732s Mitsue), 732s 903 (732s Mitsue), 732s 904 (732s Mitsue) Protection upgrade. Remove old protection, cut over to new protection and cut over equipment status, control and alarms to new station controller.  
ATCO 08-Jul-25 08:00 11-Jul-25 17:00 3.38 Days
Continuous		 7L701 (757s Battle River - 7LA701 tap) Install interphase spacers  
ATCO, ALTALINK 12-Jul-25 08:00 15-Jul-25 17:00 3.38 Days
Continuous		 7L701D1 (7LA701 tap), 701L (223s Strome - 7LA701 tap) Install interphase spacers  
ATCO, ALTALINK 12-Jul-25 08:00 15-Jul-25 17:00 3.38 Days
Continuous		 701L (223s Strome - 7LA701 tap) Install interphase spacers  
ATCO 21-Jul-25 14:00 04-Aug-25 11:00 13.88 Days
Continuous		 9L56 (720s Wabasca - 732s Mitsue), 732s 906 (732s Mitsue), 732s 904 (732s Mitsue) Protection upgrade. Remove old protection, cut over to new protection and cut over equipment status, control and alarms to new station controller.  
ATCO 05-Aug-25 08:00 07-Aug-25 16:30 2.35 Days
Continuous		 7L702 (137s Sedgewick - 757s Battle River) Interphase spacers and pole replacements  
ALTALINK 05-Aug-25 08:00 07-Aug-25 16:30 2.35 Days
Continuous		 702L (137s Sedgewick - 757s Battle River) Interphase spacers and pole replacements  
ATCO 11-Aug-25 10:00 14-Aug-25 16:30 3.27 Days
Continuous		 7L702 (137s Sedgewick - 757s Battle River) Interphase spacers and pole replacements  
ALTALINK 11-Aug-25 10:00 14-Aug-25 16:30 3.27 Days
Continuous		 702L (137s Sedgewick - 757s Battle River) Interphase spacers and pole replacements  
ATCO 18-Aug-25 10:00 21-Aug-25 16:30 3.27 Days
Continuous		 7L702 (137s Sedgewick - 757s Battle River) Interphase spacers and pole replacements  
ALTALINK 18-Aug-25 10:00 21-Aug-25 16:30 3.27 Days
Continuous		 702L (137s Sedgewick - 757s Battle River) Interphase spacers and pole replacements  
ATCO, ALTALINK 29-Sep-25 08:30 03-Oct-25 17:30 4.38 Days
Continuous		 7L77 (395s North Holden - 709s Vegreville) Install interphase spacers  
ATCO, ALTALINK 29-Sep-25 09:00 03-Oct-25 17:00 4.33 Days
Continuous		 7L77 (395s North Holden - 709s Vegreville) Install interphase spacers  
ALTALINK 01-Oct-25 08:00 11-Nov-25 17:00 41.42 Days
Continuous		 102s SVC (102s Langdon), 102s T4 (102s Langdon) the controls change AB-BC
ATCO 14-Oct-25 08:00 21-Oct-25 17:00 7.38 Days
Continuous		 7L171 (802s Michichi Creek - 804s Wintering Hills) Install interphase spacers  
ATCO 03-Nov-25 12:00 09-Dec-25 17:00 36.21 Days
Continuous		 9L99 (801s Anderson - 807s Sheerness) Replace Breaker 901 @ 807S Sheerness, complete line 21A, 21B/9L99 protection upgrade and Commissioning  
ATCO 08-Dec-25 13:00 11-Dec-25 15:00 3.08 Days
Continuous		 7L89 (721s La Corey - 826s Marguerite Lake) Line to ground clearance mitigation spans 202-203; 209-210; 216-217-218; 217-218; 221-222-223-224; 255-256; 313-314-315  
ATCO 15-Dec-25 13:00 18-Dec-25 15:00 3.08 Days
Continuous		 7L89 (721s La Corey - 826s Marguerite Lake) Line to ground clearance mitigation spans 202-203; 209-210; 216-217-218; 217-218; 221-222-223-224; 255-256; 313-314-315  
ATCO, SUNCOR 23-Mar-26 08:00 29-Mar-26 20:00 6.5 Days
Continuous		 29PL9-2 (29EDD-1 Millennium - 848s Ruth Lake) BP (Corey) - 29EDD1;29CVT-1 SYSTEM;PM 5y,10y  
ATCO 13-Apr-26 10:00 18-Apr-26 17:00 5.29 Days
Continuous		 7L22 (790s Poplar Hill - 7L88 tap) Cut open 7L22, connect new line section to new 2061S Dobbs
7L22/21B relay upgrades at 790S Poplar Hill and 811S Clairmont Lake
On completion energize new 2061S Dobbs substation		  
ATCO 03-May-26 10:00 04-May-26 17:00 31 Hours
Continuous		 7L22 (811s Clairmont Lake - 7L88 tap) 7L22/21B relay upgrade at 811S Clairmont Lake
Upon completion new 2061S Dobbs substation ready to energize		  
ATCO 04-May-26 09:00 01-Jun-26 17:30 28.35 Days
Continuous		 13L50 (2029s Heathfield - 2075s Newell) Kinbrook Addition to 2075s  
ATCO 04-May-26 09:00 01-Jun-26 17:30 28.35 Days
Continuous		 2029s T11 (2029s Heathfield) Kinbrook Addition to 2075s Newell.  
ATCO 04-May-26 09:00 01-Jun-26 17:30 28.35 Days
Continuous		 2075s T11 (2075s Newell) Kinbrook Addition to 2075s Newell.  
ATCO 19-May-26 09:00 19-May-26 17:00 8 Hours
Continuous		 9L16 (755s Cordel - 972s Tinchebray), 755s 904 (755s Cordel), 755s 905 (755s Cordel), 972s 903 (972s Tinchebray) Disconnect 9L16 from existing A-frame deadend and 9L16D2 (to be renamed 9L86D1)
Restore bus leave renamed 9L86D1 open for future line connection.
  
ATCO 19-May-26 09:00 29-May-26 17:00 10.33 Days
Continuous		 9L16 (755s Cordel - 972s Tinchebray) Disconnect 9L16 from existing A-frame deadend and 9L16D2 (to be renamed 9L86D1)
Restore bus leave renamed 9L86D1 open for future line connection.
  
ATCO 08-Mar-27 10:00 17-Mar-27 17:00 9.25 Days
Continuous		 9L24 (946s Oakland - 959s Lanfine), 959s 906 (959s Lanfine), 959s 905 (959s Lanfine), 946s 902 (946s Oakland), 946s 903 (946s Oakland) Replace A/B protection relays at 959S Lanfine and 946S Oakland
Cut in and reroute 9L24
Connect new 9LA24 T-tap
Commission Telecom and Protection to new 1072S Rose Lynn substation		  

AB-BC, AB-SK & AB-MATL: refer to AESO web posting: http://itc.aeso.ca/itc/public/atc
Also,
AB-BC, AB-SK & AB-MATL: refer to ISO Rule 203.6: http://www.aeso.ca/rulesprocedures/18592.html

Prepared On: 2024-12-11   15:04:54


This document and the information contained herein are based upon information and data which by their nature contain a degree of uncertainty and are subject to change. In addition, this document may contain information and data from public sources and/or third parties, which have been assumed to be accurate and complete and have not been verified. Accordingly, the Independent System Operator, operating as the Alberta Electric System Operator (the "AESO") makes no warranty, representation or guarantee, express or implied, with respect to this document or the information contained herein, including, but not limited to, any warranty, representation or guarantee of accuracy, completeness, timeliness, reliability, availability, absence of computer virus, non- infringement, merchantability or suitability for any purpose. Under no circumstances will the AESO, its members, officers, employees, contractors or agents, or any of their respective affiliates, be liable for any errors or omissions in, or any losses, damages or claims whatsoever, whether in contract, tort or otherwise, arising from use of or reliance upon, this document or any information contained herein.

© 2009 Alberta Electric System Operator. All rights reserved