Alberta Electric System Operator
Long Range Significant Transmission Outages for the period of 24 months starting 2026-10-10

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.

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Owner From To Duration Element Scheduled Activity Affected Intertie
SUNCOR 04-Jan-26 08:00 16-Oct-26 20:00 5,791 Hours
Continuous		 29EDD-34 260kV Bus 29PP-45 (29EDD-34), 29EDD-34 29-952-113 (29EDD-34), 29EDD-34 29PS-216 (29EDD-34) urgent repairs on 29PT-224 at 29EDD34 on 29PP-45 bus  
ALTALINK 14-Jul-26 08:00 22-Oct-26 17:00 1,905 Hours
Continuous		 287s 552 (287s Hazelwood) 287s552 must be open during 443L and 417L outage for the 214s AIS to work properly  
ALTALINK 15-Jul-26 14:01 22-Oct-26 09:00 1,962.98 Hours
Continuous		 417L (55s Olds - 281s Johnson), 55s T1 (55s Olds), 55s T2 (55s Olds), 55s 417 (55S Olds), 287s 552 (287s Hazelwood), 55s 2 (55s Olds) mobile install at 55s for P_C major upgrade, repair/replace s80, s83, s84. salvage s51.  
ALTALINK, TRANSALTA 02-Sep-26 07:00 21-Oct-26 15:00 1,184 Hours
Continuous		 320p GT3 (320p Keephills) maintenance  
EPCOR 28-Sep-26 07:00 31-Dec-26 17:00 2,267 Hours
Continuous		 816s T1 (816s Petrolia) emergency outage - tap changer gassing  
ALTALINK, Lethbridge 28-Sep-26 12:00 15-Oct-26 17:00 413 Hours
Continuous		 725L (674s Bowron - 725BL tap), 674s 725W (674s Bowron), 674s 1 (674s Bowron), 674s T1 (674s Bowron) OE outage on 725lw required to replace 674s1-disconnect switch, 674sPT4-CVT, 674sPTB2-3phase CVT's  
EPCOR 05-Oct-26 07:00 18-Oct-26 17:00 322 Hours
Continuous		 CV5 (EP 511s Victoria - 557s Castle Downs), EP 511s Victoria T5 (EP 511s Victoria), 557s CD2405 (557s Castle Downs), 557s CD2406 (557s Castle Downs), EP 511s V2401 (EP 511s Victoria), EP 511s V727 (EP 511s Victoria), EP 511s V728 (EP 511s Victoria), EP 511s VDS25 (EP 511s Victoria) manhole inspections and maintenance and 72kV breaker fail protection upgrade cutovers and commissioning  
ALTALINK 05-Oct-26 08:00 15-Oct-26 16:00 248 Hours
Continuous		 443L (55s Olds - 214s Innisfail), 214s 443 (214s Innisfail), 55s 443 (55S Olds) update line protections for 443L  
ALTALINK 05-Oct-26 08:00 28-Nov-26 19:00 1,295 Hours
Continuous		 62s T2 (62s Brazeau Plant), 62s 2 (62s Brazeau Plant) maintenance  
BCH, BPA 05-Oct-26 09:00 16-Oct-26 17:00 272 Hours
Continuous		 5L52 (BPA Custer - BCH Ingledow) 5L52 tower replacements AB-BC
ATCO 05-Oct-26 11:00 10-Oct-26 19:00 128 Hours
Continuous		 13L50L2 (2029s Heathfield - 2075s Newell) emergency repair OHSW at strs 986, 1132, 1303, 1305, 1332  
ATCO 05-Oct-26 12:00 16-Oct-26 12:00 96 Hours
Continuous		 786s SVC (786s High Level), 786s 703T (786s High Level), 786s 703 (786s High Level) ET 1136310 786S High Level SVC DFR upgrade
 
Syncrude 07-Oct-26 08:00 28-Oct-26 16:00 512 Hours
Continuous		 1335 (Syncrude Mildred Lake), 134 (Syncrude Mildred Lake), 135 (Syncrude Mildred Lake), Mildred T1 (Syncrude Mildred Lake), Mildred T2 (Syncrude Mildred Lake), 2235 (Syncrude Mildred Lake), 234 (Syncrude Mildred Lake), 235 (Syncrude Mildred Lake), 3235 (Syncrude Mildred Lake), 335 (Syncrude Mildred Lake), 334 (Syncrude Mildred Lake), Mildred T3 (Syncrude Mildred Lake), Mildred T16 (Syncrude Mildred Lake), 1635 (Syncrude Mildred Lake), 1634 (Syncrude Mildred Lake), 1434 (Syncrude Mildred Lake), 1435 (Syncrude Mildred Lake), Mildred T14 (Syncrude Mildred Lake), Mildred T19 (Syncrude Mildred Lake), 1935 (Syncrude Mildred Lake), 1934 (Syncrude Mildred Lake), 814 (Syncrude Mildred Lake), 815 (Syncrude Mildred Lake), 816 (Syncrude Mildred Lake), Mildred Lake 72kV Bus B (Sycrude Mildred Lake), ML1 (D05 - Syncrude Mildred Lake), 915 (Syncrude Mildred Lake), 1225 (Syncrude Mildred Lake), D05 76 (D05) SCL - Perform 72kV "B" Bus PM in Plant 31 at Mildred Lake.

  
ATCO 12-Oct-26 10:00 15-Oct-26 16:00 78 Hours
Continuous		 888s 906 (888s Dover) 21A/9L74 relay replacement. Cutover breaker and CT to new protection  
ALTALINK 12-Oct-26 11:00 12-Oct-26 13:30 2.5 Hours
Daily		 345s 745 (345s Hornbeck), 602s 745N (602s Cold Creek), 975s 745 (975s Dalehurst), 745A1L (975s Dalehurst - 745AL tap), 745AL (745A1L tap - 745L tap), 745L (345s Hornbeck - 745AL tap), 745L (602s Cold Creek - 745AL tap) 745L de-energized to open 745L482 switch.  
ATCO, ALTALINK 13-Oct-26 07:00 17-Oct-26 17:00 106 Hours
Continuous		 962L (87s Gaetz - 972s Tinchebray) 962L Interphase spacer work From Span 1 through 243 Using HEC with a Helicopter  
ATCO, ALTALINK 13-Oct-26 07:00 17-Oct-26 17:00 106 Hours
Continuous		 986L (87s Gaetz - 972s Tinchebray) 986L Interphase spacer work From Span 1 through 243 using HEC with a Helicopter  
ATCO, ALTALINK 13-Oct-26 07:00 17-Oct-26 17:00 106 Hours
Continuous		 9L62 (87s Gaetz - 972s Tinchebray) AltaLink Request: Interphase spacer work From Span 1 through 243 using HEC with a Helicopter.
ATCO needs to enable the following RAS logics
RAS 134 Logic 1b, RAS 134 Logic 2, RAS 211, RAS 215 , 973S RAS 134 , 615S RAS 134, 1045S RAS 134		  
ATCO, ALTALINK 13-Oct-26 07:00 17-Oct-26 17:00 106 Hours
Continuous		 9L86 (87s Gaetz - 972s Tinchebray) AltaLink Request: Interphase spacer work From Span 1 through 243 using HEC with a Helicopter.
ATCO needs to enable the following RAS logics
RAS 134 Logic 1b, RAS 134 Logic 2, RAS 211, RAS 215 , 973S RAS 134 , 615S RAS 134, 1045S RAS 134		  
BCH, BPA 13-Oct-26 09:00 16-Oct-26 17:00 80 Hours
Continuous		 5L52 (BPA Custer - BCH Ingledow) glass replacement AB-BC
ATCO 13-Oct-26 10:00 16-Oct-26 16:00 102 Hours
Continuous		 951s SVC (951s Thickwood) Annual maintenance/inspection, config changes.919A B Phase requires adjustment.  
ALTALINK 13-Oct-26 12:30 15-Oct-26 17:00 52.5 Hours
Continuous		 89s 952 (89s Ellerslie), 89s 652 (89s Ellerslie), 89s 1352 (89s Ellerslie), 89s 252 (89s Ellerslie), 89s 1789 (89s Ellerslie), 89s T1 (89s Ellerslie), 89s Ellerslie 240kV Bus 1 89s1352 Low gas top up

Switch repairs/hot spots on;
-89s26
-89s25 (Will not open to 90deg)
-89s17
-89s9
-89s1		  
ALTALINK 14-Oct-26 07:30 15-Oct-26 17:00 33.5 Hours
Continuous		 74s 77 (74s Janet), 74s T2 (74s Janet) 74sT2 LO_SLOWGAS_PRD_MT Issue  
ATCO, AIRLIQUIDE 14-Oct-26 12:15 15-Oct-26 16:00 28 Hours
Continuous		 ALC03L (402s Scotford Expansion One - 408s Air Liquide Scotford) Insulator cleaning and deficiency repair on ALC03L. Avian mitigation bird perch deterrents  
ALTALINK 15-Oct-26 08:00 15-Oct-26 18:00 10 Hours
Continuous		 158s 763N (158s Vauxhall), 28s 47 (28s West Brooks), 28s 31 (28s West Brooks), 447s 763A (447s Enchant), 447s 16 (447s Enchant), 763AL (447s Enchant - 763A1L tap), 763L (158s Vauxhall - 763AL tap), 763L (28s West Brooks - 763AL tap) 447s27 Replace line VT. (Like for like replacement)  
ALTALINK, TRANSALTA, Lethbridge 15-Oct-26 13:00 15-Oct-26 18:00 3.83 Hours
Continuous		 15s 725 (15s Fort Macleod), 725BL (240s McBride Lake - 725L tap), 725L (15s Fort MacLeod - 725BL tap), 725L (674s Bowron - 725BL tap) Advice to City of Lethbridge to close their Open Point.  
Lethbridge, ALTALINK 15-Oct-26 14:00 15-Oct-26 17:00 3 Hours
Continuous		 674s 1 (674s Bowron), 725L (674s Bowron - 725BL tap) 725L line Outage required on 725LW to close Open Point “A” at structure #1 to 674s1 at 674s substation  
ATCO 16-Oct-26 10:00 19-Oct-26 16:00 78 Hours
Continuous		 888s 905 (888s Dover) 21A/9L74 relay replacement. Cutover breaker and CT to new protection  
ALTALINK 18-Oct-26 07:00 18-Oct-26 17:00 10 Hours
Continuous		 121s 831N (121s Brooks), 339s 831 (339s Duchess), 831AL (227s Cutting Lake - 831L tap), 831L (121s Brooks - 831AL tap), 831L (339s Duchess - 831AL tap) Install bird flight diverters in ahead spans of 831L Str 4, 5, 89-97, 105-108, 112-116, 153, 145, 150 and 155.  
ALTALINK 19-Oct-26 07:00 20-Oct-26 08:00 25 Hours
Continuous		 15s 180N (15s Fort Macleod), 180L (15s Fort Macleod - 180AL tap) Customer at 604s maintenance to 604s1 disconnect and CVT.  
EPCOR 19-Oct-26 07:00 23-Oct-26 17:00 96.02 Hours
Continuous		 T2 (EP Riverview) Riverview - TX2 emergency conservator repair  
EPCOR 19-Oct-26 07:00 11-Dec-26 17:00 1,283 Hours
Continuous		 814s T2 (814s Bellamy), BR722 (Rossdale), 814s B2402 (814s Bellamy), 814s B2406 (814s Bellamy), T1 (Rossdale), R721 (Rossdale), RR723 (Rossdale) Bellamy: TX2 Emergency Bushing Replacement and Rossdale TX1 Installation  
ALTALINK 19-Oct-26 07:30 23-Oct-26 17:00 105.5 Hours
Continuous		 AML 511s 1152 (AML 511s Crossings), AML 511s T30 (AML 511s Crossings) Annual standard maintenance  
ALTALINK 19-Oct-26 09:00 23-Oct-26 17:30 104.5 Hours
Continuous		 288s 152 (288s Wolf Creek), 288s 352 (288s Wolf Creek), 1083L (63s Red Deer - 288s Wolf Creek) 1083L Line maintenance, 288s1083 switch repair  
BCH, BPA 19-Oct-26 09:00 30-Oct-26 17:00 272 Hours
Continuous		 5L51 (BPA Custer - BCH Ingledow) tower replacement AB-BC
ALTALINK 19-Oct-26 10:00 19-Oct-26 17:30 5.5 Hours
Continuous		 102s 552 (102s Langdon) URGENT: 102s552 Low gas on associated CT.  
ALTALINK 19-Oct-26 11:00 23-Oct-26 11:00 96 Hours
Continuous		 163s 1552 (163s Amoco Empress) 1552 Breaker failure and control protection upgrade  
ALTALINK, ICPCL 19-Oct-26 11:00 23-Oct-26 17:30 102.5 Hours
Continuous		 225AL (313s Raymond Reservoir - 225L tap), 225L (225s Magrath - 225AL tap), 225L (67s Stirling - 225AL tap) Line maintenance
 
ALTALINK 19-Oct-26 14:00 20-Oct-26 16:00 26 Hours
Daily		 62s 2 (62s Brazeau Plant) Breaker maintenance on 62s2  
ALTALINK 20-Oct-26 07:00 20-Oct-26 17:00 10 Hours
Continuous		 61s 202X (61s Lodgepole), 62s 202 (62s Brazeau Plant), 202L (61s Lodgepole - 62s Brazeau Plant) Install temporary grounds and lift line for high load move crossing between 202L Str 143 &144.  
Syncrude 20-Oct-26 08:00 21-Oct-26 16:00 32 Hours
Continuous		 T11 (Aurora), 14 (Aurora), 24 (Aurora), 34 (Aurora), 213 (Aurora), 223 (Aurora) Replace seal in relay on T11 in G01 Substation  
SUNCOR 20-Oct-26 08:00 25-Oct-26 20:00 156 Hours
Continuous		 29EDD-2 29PT-3 (29EDD-2 Tar Island), 29PL6-22 (29EDD-1 Millennium - 29EDD-2 Tar Island) 29EDD2; 29PP-2; 39PT-401 & 30PP-52 SYSTEM;PM 5y - 450504726; 29PT-3 Bushing Replacement; 29EDD2;39PT-401 & 30PP-52 SYSTEM;PM 5y
  
ATCO, GREENGATEP 20-Oct-26 09:00 03-Nov-26 17:30 345.5 Hours
Continuous		 801s 902 (801s Anderson), 801s 903 (801s Anderson), 9L59 (801s Anderson - 9LA59 tap), 9L59 (972s Tinchebray - 9LA59 tap) Replacement of failed 9L59D1 at 801s Anderson  
BCH 21-Oct-26 08:00 23-Oct-26 16:00 56 Hours
Continuous		 T3 (BCH Natal) inspection/doble AB-BC
ALTALINK 22-Oct-26 08:00 29-Oct-26 09:00 169 Hours
Continuous		 214s 443 (214s Innisfail), 55s 443 (55S Olds), 55s T2 (55s Olds), 443L (55s Olds - 214s Innisfail) Remove mobile.  
ALTALINK 22-Oct-26 13:00 31-Dec-27 17:00 10,445 Hours
Continuous		 359s T2 (359s Esso West Pembina) Replace T2 HV bushings. Replace T2 H0 & X0 bushings. T2 maintenance, oil leak repair, LTC filter install. T2 metering replacement.  
Syncrude 23-Oct-26 08:00 06-Nov-26 16:00 345 Hours
Continuous		 11A (Aurora), 21A (Aurora), 31A (Aurora), 89-210 (Aurora), 89-51 (Aurora), T1 (Aurora), 211A (Aurora), 221A (Aurora), 260kV Bus 1 (Aurora), 72 kV Bus 1 (Aurora) 6yr PM  
ALTALINK 23-Oct-26 09:00 23-Oct-26 13:00 4 Hours
Continuous		 163s 1752 (163s Amoco Empress) 11/1552 breaker fail trip testing  
ALTALINK, BCH 24-Oct-26 05:00 24-Oct-26 08:00 3 Hours
Continuous		 1L274 (BCH Natal - BCH Line Creek tap), 1L274 (BCH Elkford tap - BCH Line Creek tap) test energize new equipment AB-BC
ALTALINK, EPCOR 24-Oct-26 07:00 25-Oct-26 17:00 34 Hours
Continuous		 1044L (EP 805s Jasper - 816s Petrolia), 816s P2405 (816s Petrolia), 816s P2406 (816s Petrolia) Petrolia/1044L: CT Wiring Changes  
ALTALINK 25-Oct-26 07:00 25-Oct-26 17:00 10 Hours
Continuous		 121s 831N (121s Brooks), 227s 831AW (227s Cutting Lake), 339s 831 (339s Duchess), 831AL (227s Cutting Lake - 831L tap), 831L (121s Brooks - 831AL tap), 831L (339s Duchess - 831AL tap) Install bird flight diverters in ahead spans of 831L Str 4, 5, 89-97, 105-108, 112-116, 153, 145, 150 and 155.  
ALTALINK 26-Oct-26 07:00 28-Oct-26 17:00 58 Hours
Continuous		 17s 5 (17s Benalto), 17s 4 (17s Benalto), 42s 906N (42s Sarcee), 906L (17s Benalto - 42s Sarcee) Install bird flight diverters in ahead spans of 906L Str 283 - 293, as part of 2026 Bird Marker Program.  
ALTALINK, EPCOR 26-Oct-26 07:00 30-Oct-26 17:00 106 Hours
Continuous		 909L (89s Ellerslie - 665s Dome), 665s D2401 (665s Dome), 665s D2404 (665s Dome), 72DS26 (665s Dome - Strathcona) 909LE/Dome: Dome CVT LCR and 909LE Metering Upgrade  
EPCOR 26-Oct-26 07:00 30-Oct-26 17:00 106 Hours
Continuous		 EP 803s T2 (EP 803s Lambton), EP 803s L2402 (EP 803s Lambton), EP 803s L2405 (EP 803s Lambton) Lambton: TX2 Zone, DFR Cutovers and Commissioning  
EPCOR 26-Oct-26 07:00 18-Dec-26 17:00 1,283 Hours
Continuous		 805s T3 (805s Jasper), EP 805s J2404 (EP 805s Jasper), EP 805s J2405 (EP 805s Jasper) Jasper: J2404/JAB3/JDS9 Replacement LCR  
ALTALINK 26-Oct-26 08:00 28-Oct-26 18:00 58 Hours
Continuous		 924L (102s Langdon - 356s Milo) 924L192 Urgent repair Interphase spacer replacement. 924L Wire inspection span 33-34, 76-77, 86-87.
Proximity R/B's on 927L		  
ENMAX, ALTALINK 26-Oct-26 08:00 04-Nov-26 16:00 225 Hours
Continuous		 24.83L (74s Janet - SS-24), 74s 24.83X (74s Janet) Enmax Steel pole installation  
ATCO 26-Oct-26 08:00 13-Nov-26 17:00 442 Hours
Continuous		 806s 701T (806s Oldman River) Telecommunications Upgrade, new UPS upgrades.  
ATCO 26-Oct-26 09:00 26-Oct-26 17:30 32 Hours
Continuous		 757s 704 (757s Battle River) BREAKER SF6 LTB145D1/B TESTING - 704 @ 757S
PRC-005 - TRIP COIL TESTING - BREAKER 704 @ 757S
  
ALTALINK, EPCOR 26-Oct-26 09:00 30-Oct-26 17:30 104.5 Hours
Continuous		 89s 1052 (89s Ellerslie), 89s 1152 (89s Ellerslie), 909L (89s Ellerslie - 665s Dome) 909LE/Dome: Dome CVT LCR and 909LE Metering Upgrade  
ATCO 26-Oct-26 10:00 29-Oct-26 16:00 78 Hours
Continuous		 9L74 (888s Dover - 960s Birchwood Creek), 888s 905 (888s Dover), 888s 906 (888s Dover), 960s 901 (960s Birchwood Creek), 960s 902 (960s Birchwood Creek) 21A/9L74 relay three terminal line testing  
ALTALINK 26-Oct-26 11:00 04-Nov-26 11:00 217 Hours
Continuous		 163s 1252 (163s Amoco Empress) 1252 Breaker failure & control protection upgrade  
ALTALINK 26-Oct-26 12:00 30-Oct-26 13:00 97 Hours
Continuous		 602s T1 (602s Cold Creek) Replace 25kv MOD switch 602s10  
ALTALINK 27-Oct-26 07:00 27-Oct-26 17:00 10 Hours
Continuous		 AML 511s 5252 (AML 511s Crossings) PRC Relay Maintenance on 5252 Siemens 6MD  
ALTALINK 27-Oct-26 08:30 30-Oct-26 16:30 80 Hours
Continuous		 836L (61s Lodgepole - 283s Violet Grove), 61s 836N (61s Lodgepole) CT Replacement of CTs associated with 61s836N Breaker (CTL8)  
ALTALINK 28-Oct-26 07:00 28-Oct-26 15:00 8 Hours
Continuous		 AML 511s 5352 (AML 511s Crossings) PRC Relay Maintenance on 5352 Siemens 6MD  
EPCOR 28-Oct-26 07:00 28-Oct-26 17:00 10 Hours
Continuous		 557s CD2401 (557s Castle Downs) Castledowns: CD2401 NAIT Student Substation Tour  
SUNCOR 28-Oct-26 09:00 03-Nov-26 19:00 155 Hours
Continuous		 29EDD-34 260kV Bus 29PP-45 (29EDD-34) 29EDD34 29PP45 A,C phase rebuild bus and supports that were removed as part of the 29PT-224 outage.

  
ALTALINK 28-Oct-26 10:00 28-Oct-26 14:00 4 Hours
Continuous		 250p 1 (250p Bighorn Plant) maintenance  
ALTALINK 29-Oct-26 07:00 29-Oct-26 17:00 10 Hours
Continuous		 AML 511s 5052 (AML 511s Crossings) PRC Mnt 0511DC ACF1 (s5052) 6MD66 CI  
ENMAX, ALTALINK 29-Oct-26 08:00 29-Oct-26 16:00 8 Hours
Continuous		 23.80L (74s Janet - SS-23), 23.4TR (SS-23) SW84 @ 23 SUB north phase braid hot spot - 90 deg C  
ALTALINK 29-Oct-26 08:00 29-Oct-26 17:00 9 Hours
Continuous		 28s 44 (28s West Brooks), 28s R1 (28s West Brooks) 28s R1 Install continuous loops for LA's grounding  
ALTALINK 29-Oct-26 08:00 31-Oct-26 18:00 58 Hours
Continuous		 927L (102s Langdon - 356s Milo) 927L - (Urgent repair) Replace 2 Interphase spacers in span 188  
ALTALINK 29-Oct-26 10:00 29-Oct-26 14:00 4 Hours
Continuous		 250p 2 (250p Bighorn Plant) maintenance  
ALTALINK 01-Nov-26 07:00 01-Nov-26 17:00 10 Hours
Continuous		 121s 831N (121s Brooks), 227s 831AW (227s Cutting Lake), 339s 831 (339s Duchess), 831AL (227s Cutting Lake - 831L tap), 831L (121s Brooks - 831AL tap), 831L (339s Duchess - 831AL tap) Install bird flight diverters in ahead spans of 831L Str 4, 5, 89-97, 105-108, 112-116, 153, 145, 150 and 155.  
ENMAX, ALTALINK 01-Nov-26 08:30 14-Nov-26 16:00 293.5 Hours
Continuous		 37.2TR (SS-37), 37.82L (74s Janet - SS-37) HV SW Replacement. 37SW85, 37SW86, 37SW89. HV SW Maintenance MD-37.2TR  
ALTALINK, ENMAX 01-Nov-26 08:30 14-Nov-26 16:00 322 Hours
Continuous		 74s 37.82W (74s Janet), 37.82L (74s Janet - SS-37) ENMAX Work - HV SW Replacement. 37SW85, 37SW86, 37SW89  
ALTALINK, EPCOR 02-Nov-26 07:00 13-Nov-26 17:00 274 Hours
Continuous		 909L (310p Sundance - 665s Dome), 665s D2403 (665s Dome) Dome: 909LW/D2403, Metering Upgrade Cutovers and Commissioning  
ENMAX, ALTALINK 02-Nov-26 08:00 02-Nov-26 17:30 9.5 Hours
Daily		 1080L (SS-25 - SS-65) Oil sampling required on cables  
BCH, BPA 02-Nov-26 08:00 06-Nov-26 18:30 106.5 Hours
Continuous		 5L51 (BPA Custer - BCH Ingledow) tower replacement AB-BC
ALTALINK 02-Nov-26 11:00 04-Nov-26 15:00 52 Hours
Continuous		 163s T1 (163s Amoco Empress) Breaker Fail upgrade project: 11/1252 & 11/1552 breaker fail trip testing. Trip testing of 163s501, 163sXA, 163sXB, Replace T1 Tap Changer controller, And Change CT ratio and protection setting update.  
ALTALINK 03-Nov-26 07:00 03-Nov-26 17:00 10 Hours
Continuous		 510s 2552 (510s Sunnybrook) PRC Relay Mnt 0510DC ACF1 (s2552) 6MD66 CI  
ENMAX, ALTALINK 03-Nov-26 07:00 03-Nov-26 17:30 10.5 Hours
Daily		 1109L (SS-25 - SS-65) 1109L 1 day for oil sample, grounding clean up, and transferring Y(B) phase to the spare cable connection and transferring the monitoring to this phase.  
ATCO 03-Nov-26 09:00 03-Nov-26 14:00 5 Hours
Continuous		 888s 902 (888s Dover) New 21B/9L74 relay has 50BF/906 function internally. Must trip adjacent breakers to 906.  
ALTALINK 03-Nov-26 09:00 07-Nov-26 17:00 104 Hours
Continuous		 71s T2 (71s Lamoureux), 71s 240kV East Bus (71s Lamoureux), 71s 1752 (71s Lamoureux), 71s 1452 (71s Lamoureux), 71s 1352 (71s Lamoureux), 71s 32 (71s Lamoureux) multiple switch repair/replacement and maintenance 71s36, 71s37, 71s46, 71s47  
ATCO, ALTALINK 03-Nov-26 10:00 10-Nov-26 17:00 175 Hours
Continuous		 7L230 (743s Sarah Lake - 888AL tap), 743s 7L230D1 (743s Sarah Lake) Replace 7L230D1 disconnect switch  
ALTALINK 04-Nov-26 07:00 04-Nov-26 17:00 10 Hours
Continuous		 510s 1952 (510s Sunnybrook) PRC Relay Mnt 0510DC ACF1 (s1952) 6MD66 CI  
BCH 04-Nov-26 08:00 17-Nov-26 12:00 316 Hours
Continuous		 5L98 (BCH Nicola - BCH Vaseux Lake) replacement of equipment AB-BC
ATCO 04-Nov-26 09:00 04-Nov-26 14:00 5 Hours
Continuous		 888s 909 (888s Dover) New 21B/9L74 relay has 50BF/906 function internally. Must trip adjacent breakers to 906. 21A/9L74 will still be protecting 9L74. 21B/9L74 will be blocked as to not affect other in service protection.  
ALTALINK 04-Nov-26 09:30 04-Nov-26 12:30 3 Hours
Continuous		 163s 1552 (163s Amoco Empress) 11/1252 Breaker Fail trip testing  
ATCO 04-Nov-26 10:00 09-Nov-26 19:00 129 Hours
Continuous		 9L20 (755s Cordel - 766s Nevis) Installing spacer dampers on Line with heli supported methods.  
ALTALINK 04-Nov-26 12:30 04-Nov-26 16:00 3.5 Hours
Continuous		 163s 1352 (163s Amoco Empress) 11/1252 breaker fail trip testing  
ALTALINK 05-Nov-26 03:30 05-Nov-26 06:30 3 Hours
Continuous		 62s 1 (62s Brazeau Plant) maintenence  
ALTALINK 05-Nov-26 07:00 05-Nov-26 17:00 10 Hours
Continuous		 510s 2052 (510s Sunnybrook) PRC Relay Mnt 0510DC ACF2 (s2052) 6MD66 CI  
ALTALINK 05-Nov-26 07:00 05-Nov-26 18:00 11 Hours
Continuous		 61s 202X (61s Lodgepole), 62s 202 (62s Brazeau Plant), 202L (61s Lodgepole - 62s Brazeau Plant) 202L Urgent Repair - Replace crossarms and insulators structure 37 / Replace entire structure 75  
ATCO 05-Nov-26 09:00 05-Nov-26 14:00 5 Hours
Continuous		 888s 912 (888s Dover) New 21B/9L74 relay has 50BF/906 function internally. Must trip adjacent breakers to 906. 21A/9L74 will still be protecting 9L74. 21B/9L74 will be blocked as to not affect other in service protection.  
ENMAX, ALTALINK 06-Nov-26 08:00 06-Nov-26 18:30 10.5 Hours
Continuous		 1109L (SS-25 - SS-65) 1109L taken out of service for -1 day and connection return to existing cable connection for Y(B) phase  
ENMAX, ALTALINK 08-Nov-26 06:00 08-Nov-26 12:00 6 Hours
Continuous		 771L (SS-47 - SS-162), 162B138-RB82 (SS-162), 47.1TR (SS-47), 47B138-771/1 (SS-47), 47B138-771 (SS-47), 47.2TR (SS-47), 162B138-RB81 (SS-162) Summer Substation Washing 162SUB, 138kV, 162MD138-771  
EPCOR 09-Nov-26 07:00 11-Dec-26 17:00 778 Hours
Continuous		 PM2405 (Poundmaker) Poundmaker: P2405 Breaker Replacement  
ATCO 09-Nov-26 08:00 09-Nov-26 20:00 12 Hours
Continuous		 7L03 (749s Flyingshot Lake - 7L09 tap) Changing burnt pole 16A and rotten structure 19  
ALTALINK 09-Nov-26 12:00 10-Nov-26 16:00 28 Hours
Continuous		 359s T2 (359s Esso West Pembina) T2 meter replacement.  
SUNCOR 10-Nov-26 10:00 15-Nov-26 18:00 128 Hours
Continuous		 29PL9-12 (29EDD-34 - 29EDD-65) Firebag: Cleaning up contamination from Pad 112 blow out 300772223  
EPCOR 12-Nov-26 07:00 14-Nov-26 17:00 58 Hours
Continuous		 557s T1 (557s Castle Downs) Castledowns: TX1 Tap Changer Maintenance  
EPCOR 16-Nov-26 07:00 20-Nov-26 17:00 106 Hours
Continuous		 EP 803s T1 (EP 803s Lambton), EP 803s L2401 (EP 803s Lambton), EP 803s L2402 (EP 803s Lambton) Lambton: TX1 Zone, DFR Cutovers and Commissioning  
ENMAX, ALTALINK 16-Nov-26 08:00 16-Nov-26 12:00 4 Hours
Continuous		 21.80L (42s Sarcee - SS-21), 21B138-21.80 (SS-21) Breaker Trip Circuit Test - 21B138-21.80  
ALTALINK, EPCOR 16-Nov-26 08:30 27-Nov-26 18:00 273.5 Hours
Continuous		 908L (89s Ellerslie - 816s Petrolia) Petrolia: 908LE Surge Arrestor and CVT LCR  
ALTALINK 16-Nov-26 09:00 17-Nov-26 17:00 32 Hours
Continuous		 71s 452 (71s Lamoureux), 71s 352 (71s Lamoureux), 71s 787X (71s Lamoureux), 787L (71s Lamoureux - 787AL tap) 71s787X switch adjustment, transmission line maintenance  
ALTALINK, EPCOR 16-Nov-26 09:30 27-Nov-26 17:00 271.5 Hours
Continuous		 908L (89s Ellerslie - 816s Petrolia), 816s P2401 (816s Petrolia), 816s P2406 (816s Petrolia) Petrolia: 908LE Surge Arrestor and CVT LCR  
ATCO 16-Nov-26 10:00 19-Nov-26 14:00 76 Hours
Continuous		 827s SVC (827s Cranberry Lake) ET 1136489 827S Cranberry Lake SVC DFR Upgrade
SVC AIR COOLED MAINTENANCE @ CRANBERRY SVC 827S		  
SUNCOR 16-Nov-26 10:00 20-Nov-26 18:00 104 Hours
Continuous		 29PL9-13 (29EDD-34 - 29EDD-65) Firebag: Replace components - 29PL9-13 Contamination clean up from Pad 112 blowout 300772224  
ATCO, ALTALINK 16-Nov-26 11:00 18-Nov-26 13:00 50 Hours
Continuous		 962L (87s Gaetz - 972s Tinchebray) Replace motor on 9L62D1  
ALTALINK 16-Nov-26 11:30 20-Nov-26 17:00 101.5 Hours
Continuous		 71s 1452 (71s Lamoureux), 71s 1352 (71s Lamoureux), 71s 997E (71s Lamoureux) Switch replacement 71s997E, switch repair 71s46.
 
ENMAX, ALTALINK 16-Nov-26 12:00 16-Nov-26 16:00 4 Hours
Continuous		 693L (42s Sarcee - SS-10), 10B138-693 (SS-10) Breaker Trip Circuit Test - 10B138-693  
ATCO 16-Nov-26 12:00 18-Nov-26 11:59 47.98 Hours
Continuous		 972s 905 (972s Tinchebray) Replace motor on 9L62D1.  
ATCO 16-Nov-26 12:00 19-Nov-26 12:00 72 Hours
Continuous		 740s 705 (740s H.R. Milner), 7L80 (740s H.R. Milner - 857s Kakwa Ridge) PRC-005 - MICROPROCESSOR RELAY TESTING
TCM Program. RTXP Test Switch Mitigation and Replacement
Both RAS-A and RAS-B 7L80 will also need be OOS for the RTXP work on 21A and 21B 7L80		  
ALTALINK 16-Nov-26 13:00 19-Nov-26 17:00 76 Hours
Continuous		 251s 1452 (251s Whitla) 251s1452 Gauge replacement, HPL open close indicator replacement. PRC5 maint.  
ENMAX, ALTALINK 17-Nov-26 08:00 17-Nov-26 16:00 8 Hours
Continuous		 693L (42s Sarcee - SS-10) Breaker Trip Circuit Test - 10B138-693.  
ENMAX, ALTALINK 17-Nov-26 12:00 17-Nov-26 16:00 4 Hours
Continuous		 23.80L (74s Janet - SS-23), 23B138-23.80 (SS-23) Breaker Trip Circuit Test - 23B138-23.80  
EPCOR 18-Nov-26 07:00 24-Nov-26 17:00 370 Hours
Continuous		 987s GT3 (987s Clover Bar), 987s CGB3 (987s Clover Bar) BUS Diff Upgrade Cutovers  
ATCO, GREENGATEP 18-Nov-26 12:00 20-Nov-26 12:00 48 Hours
Continuous		 9L16 (755s Cordel - 972s Tinchebray), 972s 908 (972s Tinchebray), 972s 909 (972s Tinchebray) Replace motor on 9L16D2.  
ALTALINK 19-Nov-26 08:00 19-Nov-26 13:00 5 Hours
Continuous		 264s 452 (264s Elkwater), 64s 452 (64s East Crossfield), 752L (64s East Crossfield - 752AL tap) Breaker outage required for downstream CT secondary connection and testing.  
ENMAX, ALTALINK 19-Nov-26 08:00 24-Nov-26 16:00 225 Hours
Continuous		 24.83L (74s Janet - SS-24) Steel pole installation  
Syncrude 20-Nov-26 08:00 02-Dec-26 16:00 296 Hours
Continuous		 D05 511 (D05), D05 511B (D05), D05 512 (D05), D05 512A (D05), D05 514 (D05), 223A (Aurora), 223 (Aurora), 222B (Aurora), 222 (Aurora), 89-225 (Aurora), AL-2 (Aurora - D05 Syncrude), 223B (Aurora), 222A (Aurora) G01 Substation - Zone 4 (AL-2) PM.  
ALTALINK, EPCOR 23-Nov-26 07:00 27-Nov-26 17:00 106 Hours
Continuous		 1058L (657s Summerside - EP 803s Lambton), EP 803s L2403 (EP 803s Lambton), EP 803s L2404 (EP 803s Lambton) 1058L: Lambton, DFR Cutovers and Commissioning  
EPCOR 23-Nov-26 07:00 01-Dec-26 17:00 202 Hours
Continuous		 1191L (987s Clover Bar - 1007s Arum Park), 987s C2410 (987s Clover Bar), 987s C2409 (987s Clover Bar) 1191L: Initial Line Energization  
ATCO 23-Nov-26 10:00 23-Nov-26 17:00 7 Hours
Continuous		 959s 904 (959s Lanfine) Cutover and Commission Bkr 904 status to RAS 204 A/B  
ATCO 23-Nov-26 10:00 24-Nov-26 15:00 29 Hours
Continuous		 813s 901 (813s Little Smoky) 813S Little Smoky - 901 S/C Open/Close Control Mapping Issue  
ATCO 23-Nov-26 13:00 30-Nov-26 13:00 168 Hours
Continuous		 930s SVC (930s Arcenciel) ET 1137010 930S Arcenciel SVC DFR Upgrade
ET 1137018 930S Arcenciel SVC Protection Upgrade
SVC AIR COOLED MAINTENANCE @ ARCENCIEL 930S		  
ALTALINK 24-Nov-26 08:00 24-Nov-26 12:00 4 Hours
Continuous		 33s 5 (33s Spray) testing  
ALTALINK 24-Nov-26 08:00 24-Nov-26 17:00 9 Hours
Daily		 63s 25 (63s Red Deer), 63s T2 (63s Red Deer) Investigate IDD alarms/test sensors and cables  
ALTALINK 24-Nov-26 08:00 25-Nov-26 11:30 27.5 Hours
Continuous		 650s 252 (650s Hansman Lake) adding a maintenance switch to 650s252  
ATCO 24-Nov-26 10:00 24-Nov-26 17:00 7 Hours
Continuous		 959s 919 (959s Lanfine) Cutover and Commission Bkr 919 status to RAS 204 A/B  
ALTALINK 24-Nov-26 13:00 24-Nov-26 17:00 4 Hours
Continuous		 33s 4 (33s Spray) testing
.		  
ATCO 25-Nov-26 10:00 25-Nov-26 17:00 7 Hours
Continuous		 959s 920 (959s Lanfine) Cutover and Commission Bkr 920 status to RAS 204 A/B  
ALTALINK 25-Nov-26 12:30 26-Nov-26 14:00 25.5 Hours
Continuous		 650s 352 (650s Hansman Lake) adding a maintenance switch to 650s352  
ALTALINK, Travers2SolarLP 26-Nov-26 13:00 26-Nov-26 17:00 4 Hours
Continuous		 356s 152 (356s Milo), 356s 252 (356s Milo), 1005AL (991s Little Bow - 1005L tap), 1005L (120s Picture Butte - 1005AL tap), 1005L (356s Milo - 1005AL tap) 356s1005 remove ferruginous Hawk Nest and relocate to a platform outside the yard.  
ALTALINK 30-Nov-26 07:00 03-Dec-26 16:00 81 Hours
Continuous		 71s 452 (71s Lamoureux), 71s 852 (71s Lamoureux), 71s 708N (71s Lamoureux), 71s 31 (71s Lamoureux), 71s T2 (71s Lamoureux), 71s 138kV East Bus (71s Lamoureux) 138kV switch repairs (71s8, 71s42, 71s708N). Installation of the two new diameters being added to 71s (240kV side)  
EPCOR, ALTALINK 30-Nov-26 07:00 04-Dec-26 17:00 106 Hours
Continuous		 EP 803s T3 (EP 803s Lambton), EP 803s L2403 (EP 803s Lambton), EP 803s L2405 (EP 803s Lambton), EP 803s L721 (EP 803s Lambton), 72LH8 (EP 803s Lambton - EP Hardisty), 72LS24 (EP 803s Lambton - Strathcona) Lambton: TX3 Zone, DFR Cutovers and Commissioning  
ALTALINK, BCH 30-Nov-26 09:00 04-Dec-26 17:00 104 Hours
Continuous		 1L274 (BCH Elkford tap - BCH Line Creek tap) replace structures AB-BC
ATCO 30-Nov-26 12:00 03-Dec-26 12:00 72 Hours
Continuous		 813s SVC (813s Little Smoky) 813S Little Smoky SVC DFR Upgrade  
EPCOR 04-Dec-26 07:00 04-Dec-26 17:00 10 Hours
Continuous		 557s T1 (557s Castle Downs), 557s CD2401 (557s Castle Downs), 557s CD2406 (557s Castle Downs) Castledowns: TX1 Zone, Wiring Changes and Op Checks  
Syncrude 05-Dec-26 08:00 09-Dec-26 16:00 104 Hours
Continuous		 D05 517 (D05), D05 519 (D05), D05 517B (D05), D05 519A (D05), D05 520 (D05), 213 (Aurora), 213A (Aurora), 211 (Aurora), 211B (Aurora), 89-215 (Aurora), AL-1 (Aurora - D05) Isolate AL-1 to allow Projects to complete 260kV Tie ins for Powerline Bypass  
ALTALINK, EPCOR 07-Dec-26 07:00 11-Dec-26 17:00 106 Hours
Continuous		 1059AL (52s East Industrial - 1059L tap), 1059L (EP 803s Lambton - 1059AL tap), EP 803s L2401 (EP 803s Lambton), EP 803s L2404 (EP 803s Lambton) 1059L: Lambton, DFR Cutovers and Commissioning  
ALTALINK 07-Dec-26 10:00 11-Dec-26 17:30 103.5 Hours
Continuous		 514L (396s Pincher Creek - 514BL tap) 514L
Structure 48 - Replace cross arm
Structure 99 - Replace structure
Structure 102 - Replace structure
Structure 158 - Replace Cross Arm 		 
ALTALINK 14-Dec-26 08:00 15-Dec-26 17:30 33.5 Hours
Continuous		 1325L (510s Sunnybrook - AML 511s Crossings) 1325L Add Bird Diverter str. protection. 1325L501- monopole catwalk install and 1325L542- Lattice  
ALTALINK, EPCOR 14-Dec-26 09:30 17-Dec-26 17:00 79.5 Hours
Continuous		 920L (37s North Calder - 557s Castle Downs), 557s CD2401 (557s Castle Downs), 557s CD2403 (557s Castle Downs) 920LW/Castledowns: Surge Arrestor LCR  
ALTALINK, EPCOR 14-Dec-26 09:30 17-Dec-26 17:00 79.5 Hours
Continuous		 920L (37s North Calder - 557s Castle Downs), 557s CD2401 (557s Castle Downs), 557s CD2404 (557s Castle Downs), 557s CDDS13 (557s Castle Downs) 920LW/Castledowns: surge arrestor LCR  
ALTALINK 16-Dec-26 10:00 16-Dec-26 14:00 4 Hours
Continuous		 250p 1 (250p Bighorn Plant) maintenance  
ALTALINK 17-Dec-26 08:00 17-Dec-26 17:30 9.5 Hours
Continuous		 936L (5s East Calgary - 102s Langdon) 936L str.67 - re-install damper on center phase  
ALTALINK 17-Dec-26 10:00 17-Dec-26 14:00 4 Hours
Continuous		 250p 2 (250p Bighorn Plant) maintenance  
ALTALINK 23-Dec-26 23:30 24-Dec-26 02:30 3 Hours
Continuous		 62s 1 (62s Brazeau Plant) maintenence  
ALTALINK 24-Dec-26 03:30 24-Dec-26 06:30 3 Hours
Continuous		 62s 2 (62s Brazeau Plant) maintenence  
EPCOR 04-Jan-27 07:00 12-Feb-27 17:00 946 Hours
Continuous		 EP 805s J2405 (EP 805s Jasper) Jasper: J2405 Replacement LCR  
ATCO 11-Jan-27 09:00 18-Jan-27 15:00 174 Hours
Continuous		 9L74 (888s Dover - 960s Birchwood Creek) 9L74 Outage required for line-to-ground clearance mitigation.
38 bucket piles to install while line is OOS, and 19 structures to replace.		  
ALTALINK 11-Jan-27 10:00 21-Jan-27 17:30 247.5 Hours
Continuous		 170L (632s Russell - 799s Coleman) 170L
Replace Structure 35
Replace Structure 36
Replace Structure 40
Replace Structure 41		  
ATCO 18-Jan-27 15:15 25-Jan-27 13:30 166.25 Hours
Continuous		 9L58 (848s Ruth Lake - 888s Dover) Line to ground clearance mitigation.
Structure replacements and deficiencies.		  
EPCOR 22-Jan-27 07:00 25-Jan-27 17:00 82 Hours
Continuous		 1055L (629s Argyll Transfer Station - 816s Petrolia), 240BA3 (629s Argyll Transfer Station - 814s Bellamy) 1055L/240BA3: ADS3 LCR Preparation Outage, jumpering out ADS2  
ALTALINK 25-Jan-27 10:00 04-Feb-27 17:30 247.5 Hours
Continuous		 799s 170E (799s Coleman), 170L (632s Russell - 799s Coleman) 170L
Replace Structures 57, 59, 60, 62, 63, 64, 65, 89, 90, 91, 92, 93, 94, 95, 96		  
ATCO 25-Jan-27 14:00 01-Feb-27 15:00 169 Hours
Continuous		 9L74 (888s Dover - 960s Birchwood Creek) 9L74 Outage required for line-to-ground clearance mitigation.
38 bucket piles to install while line is OOS, and 19 structures to replace.		  
ALTALINK, EPCOR 25-Jan-27 16:00 01-Feb-27 18:00 170 Hours
Continuous		 1056L (89s Ellerslie - 629s Argyll Transfer Station) 1056L/240BA2: ADS3 LCR (1055L and BA3 will be jumpered out and energized bypassing ADS2 for the duration of this outage)  
EPCOR, ALTALINK 25-Jan-27 17:00 01-Feb-27 17:00 168 Hours
Continuous		 240BA2 (629s Argyll Transfer Station - 814s Bellamy), 1056L (89s Ellerslie - 629s Argyll Transfer Station) 1056L/240BA2: ADS3 LCR (1055L and BA3 will be jumpered out and energized bypassing ADS2 for the duration of this outage)  
ALTALINK 27-Jan-27 08:00 28-Jan-27 18:00 34 Hours
Continuous		 847L (602s Cold Creek - 847AL tap), 602s 2082N (602s Cold Creek) Replace 847L Str.244 H-frame structure. 602s2082N to not export during the outage.  
EPCOR 01-Feb-27 17:00 05-Feb-27 17:00 96 Hours
Continuous		 1055L (629s Argyll Transfer Station - 816s Petrolia), 240BA3 (629s Argyll Transfer Station - 814s Bellamy) 1055L/240BA3: ADS3 LCR Removing ADS2 jumper, restoring configuration  
ATCO 02-Feb-27 08:00 04-Feb-27 12:00 52 Hours
Continuous		 9L01 (848s Ruth Lake - 951s Thickwood Hills) GOI required on 9L01 for pole replacements and deficiency repair  
ATCO, ALTALINK 04-Feb-27 12:30 08-Feb-27 13:30 97 Hours
Continuous		 9L47 (AML 852s Round Hill - 898s Heart Lake) Outage required on 9L47 for line-to-ground clearance mitigation
Structure replacements and installs.		  
ALTALINK 08-Feb-27 10:00 11-Feb-27 17:30 79.5 Hours
Continuous		 170L (632s Russell - 799s Coleman) 170L
Replace Structures 66, 67, 82, 83		  
EPCOR 16-Feb-27 07:00 30-Mar-27 17:00 1,017 Hours
Continuous		 EP 805s J2407 (EP 805s Jasper) Jasper: J2407 Replacement LCR  
ALTALINK 16-Feb-27 10:00 26-Feb-27 17:30 247.5 Hours
Continuous		 170L (632s Russell - 799s Coleman) 170L
Replace Structures 102 & 103		  
ATCO, ALTALINK 16-Feb-27 13:00 22-Feb-27 11:00 142 Hours
Continuous		 9L47 (AML 852s Round Hill - 898s Heart Lake) Outage required on 9L47 for line-to-ground clearance mitigation
Structure replacements and installs.		  
ALTALINK, EPCOR 19-Feb-27 07:00 05-Mar-27 17:00 346 Hours
Continuous		 1045L (EP 805s Jasper - 1045AL tap), EP 805s J2406 (EP 805s Jasper), EP 805s J2407 (EP 805s Jasper) 1045L/Jasper: J2407 Replacement LCR  
ALTALINK 19-Feb-27 07:00 05-Mar-27 18:00 347 Hours
Continuous		 1045AL (320p Keephills - 1045L tap), 1045L (310p Sundance - 1045AL tap) 1045L/Jasper: J2407 Replacement LCR  
EPCOR 22-Feb-27 07:00 05-Mar-27 17:00 274 Hours
Continuous		 814s T1 (814s Bellamy), BR721 (Rossdale), 814s B2401 (814s Bellamy), 814s B2407 (814s Bellamy) Bellamy: TX1 Temp Monitor Install  
ALTALINK 03-Mar-27 08:00 04-Mar-27 17:30 33.5 Hours
Continuous		 172L (254s Coaldale - 172EL tap) 172L str.953,1000,1002,1004 Bonding and grounding repairs, str.1004 arm change
 
ALTALINK 05-Mar-27 08:00 05-Mar-27 17:30 9.5 Hours
Continuous		 172L (83s Taber - 172EL tap) 172L str. 938 - Arm change  
EPCOR 08-Mar-27 07:00 19-Mar-27 17:00 273 Hours
Continuous		 814s B2402 (814s Bellamy), 814s B2406 (814s Bellamy), 814s T2 (814s Bellamy), BR722 (Rossdale) Bellamy: TX2 LTC Monitor Install  
ATCO 08-Mar-27 10:00 17-Mar-27 17:00 222 Hours
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		  
EPCOR 29-Mar-27 07:00 02-Apr-27 17:00 82 Hours
Continuous		 987s GT1 (987s Clover Bar), 987s SST2 (987s Clover Bar), 987s CS2 (987s Clover Bar), 987s CGB1 (987s Clover Bar), 987s CCP7214 (987s Clover Bar), 987s CC24 (987s Clover Bar), 987s CH724 (987s Clover Bar), 987s CK726 (987s Clover Bar), 987s 72kV Bus 4 (987s Clover Bar) Cloverbar: , SST2, BUS 4 Outage. CDS18 Disconnect Replacement  
EPCOR 05-Apr-27 07:00 07-May-27 17:00 778 Hours
Continuous		 52s T2 (52s East Industrial), 52s E2402 (52s East Industrial) East Industrial: TX2 Bushing Replacement  
SUNCOR 05-Apr-27 09:00 11-Apr-27 20:00 155 Hours
Continuous		 29PL9-12 (29EDD-34 - 29EDD-65) 29EDD34;29PL9-12 SYSTEM;PM 5y,10y
  
SUNCOR 06-Apr-27 09:00 16-Apr-27 20:00 251 Hours
Continuous		 29EDD-34 29PT-112 (29EDD-34), 29EDD-34 29-752-121 (29EDD-34), 29EDD-34 29PS-68 (29EDD-34), 29EDD-34 29PS-67 (29EDD-34), 29EDD-34 29PS-66 (29EDD-34), 29EDD-34 29PS-65 (29EDD-34), 29EDD-34 29PS-225 (29EDD-34), 29EDD-34 29PS-230 (29EDD-34), 29EDD-34 29-952-141 (29EDD-34), 29EDD-34 29-952-131 (29EDD-34), 29EDD-34 29-952-111 (29EDD-34) 29EDD34;29PT-112 & 29PP-24 SYSTEM;PM
This will Place 29EDD-34 on one 260 kV bus and drop 29PL7-1 		 
ATCO 12-Apr-27 10:00 19-Apr-27 17:00 175 Hours
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		  
SUNCOR 14-Apr-27 14:00 23-Apr-27 18:00 220 Hours
Continuous		 29EDD-65 29PT-0257 (29EDD-65), 29EDD-65 29-952-4812 (29EDD-65), 29EDD-65 29-952-4813 (29EDD-65), 29EDD-71 752-4624 (29EDD-71), 29EDD-71 752-4623 (29EDD-71), 29PL7-4 (29EDD-65 - 29EDD-71) Firebag: 29EDD65;29PT-257 & 29PL7-4 SYSTEM, 29EDD65 ;29PT-260 & 29PL7-4 SYSTEM, 29EDD71 29PT-241 & 29PL7-4  
ALTALINK 19-Apr-27 06:30 28-Apr-27 18:00 227.5 Hours
Continuous		 77s 652 (77s Sagitawah), 77s 752 (77s Sagitawah), 77s 40 (77s Sagitawah), 77s 57 (77s Sagitawah), 77s T2 (77s Sagitawah), 77s 29 (77s Sagitawah) Protection Upgrade 77sT2  
SUNCOR 20-Apr-27 09:00 23-Apr-27 20:00 83 Hours
Continuous		 29EDD-1 29EDD1s952 (29EDD-1 Millennium) 29EDD1s952 - faulty SF6 sensors BPC-26-014 - 300677553  
ATCO 03-May-27 09:00 17-May-27 17:30 344.5 Hours
Continuous		 2075s T11 (2075s Newell) Annual EATL outage at 2075s & 2029s.  
ATCO 03-May-27 09:00 17-May-27 17:30 344.5 Hours
Continuous		 2029s T11 (2029s Heathfield) Annual EATL outage at 2075s & 2029s.  
ATCO 03-May-27 09:00 17-May-27 17:30 344.5 Hours
Continuous		 13L50 (2029s Heathfield - 2075s Newell) Annual EATL outage at 2075s & 2029s.
**1218 IS NOT THE ISOALTION. ATCO SENT AESO OF REQUIRED ISOLATIONS BACK IN MAY 2024 TO UPDATE 2029S AND 2075S ISOLATIONS FOR 13L50 OUTAGES**		  
ATCO 03-May-27 10:00 06-May-27 17:00 79 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		  
SUNCOR 04-May-27 09:00 07-May-27 20:00 83 Hours
Continuous		 29EDD-1 29EDD1s852 (29EDD-1 Millennium) 29EDD1S852 Replace Densimeter  
SUNCOR 04-May-27 09:00 14-May-27 20:00 251 Hours
Continuous		 29EDD-34 29PS-214 (29EDD-34), 29EDD-34 29-952-113 (29EDD-34), 29EDD-34 29PS-215 (29EDD-34), 29EDD-34 29PS-213 (29EDD-34) 29EDD34;29PL9-13 SYSTEM;PM 5y,10y  
ATCO 10-May-27 10:00 11-May-27 17:00 31 Hours
Continuous		 7L03 (749s Flyingshot Lake - 7L09 tap) Cutover and commission RAS analogs and LTO to 790S Poplar Hill RAS Hub  
SUNCOR 11-May-27 09:00 14-May-27 20:00 83 Hours
Continuous		 29EDD-1 29EDD1s1052 (29EDD-1 Millennium) 29EDD1S1052 Densimeter Replacement - No visibility outage, no line outage - BPC-26-017 - 300347749  
ATCO 12-May-27 10:00 13-May-27 17:00 31 Hours
Continuous		 7L03 (731s Elmworth - 7L09 tap) Cutover and commission LTO to 790S Poplar Hill RAS Hub  
ATCO 14-May-27 10:00 15-May-27 17:00 31 Hours
Continuous		 7L69 (731s Elmworth - 815s Goodfare) Cutover and commission LTO to 790S Poplar Hill RAS Hub  
ATCO 16-May-27 10:00 17-May-27 17:00 31 Hours
Continuous		 7L07 (790s Poplar Hill - 815s Goodfare) Cutover and commission LTO to 790S Poplar Hill RAS Hub  
ATCO 28-May-27 10:00 31-May-27 18:00 80 Hours
Continuous		 959s 708 (959s Lanfine), 959s 707 (959s Lanfine), 7L238 (959s Lanfine - 601s Bufallo Bird) Cutover CT/PT ccts, Commission new RAS A-B/7L238, end-to-end testing with 601S Buffalo Bird  
SUNCOR 01-Jun-27 08:00 10-Jun-27 17:00 225 Hours
Continuous		 635EDD-1000 635-752-635PT-1000 (635EDD-1000), 635EDD-1000 635PT-1000 (635EDD-1000) FH - Maintenance on Transformer, associated breakers, other equipment in isolation boundary and protection system testing.  
SUNCOR 01-Jun-27 09:00 11-Jun-27 20:00 251 Hours
Continuous		 29EDD-94 407T (29EDD-94 Voyageur), 29EDD-94 29-952-9705 (29EDD-94 Voyageur), 29EDD-94 29PS-393 (29EDD-94 Voyageur), 29EDD-94 29PS-392 (29EDD-94 Voyageur), 29EDD-94 29-952-9704 (29EDD-94 Voyageur), 29EDD-94 29PS-400 (29EDD-94 Voyageur) 29EDD94;29PT-407 SYSTEM;PM 5y,10y  
ATCO 07-Jun-27 10:00 10-Jun-27 17:00 79 Hours
Continuous		 9L24 (946s Oakland - 959s Lanfine), 959s 906 (959s Lanfine), 959s 905 (959s Lanfine), 946s 902 (946s Oakland), 946s 903 (946s Oakland) Cutover Bkr/MOD status, Commission new LTO/RAS 204 A/B - Lanfine/Oakland  
ATCO 07-Jun-27 12:00 10-Jun-27 15:00 75 Hours
Continuous		 7L80 (733s Simonette - 857s Kakwa Ridge), 733s 701 (733s Simonette) BREAKER SF6 HPL COMPLETE TESTING - 701 @ 733S  
SUNCOR 11-Jun-27 08:00 20-Jun-27 17:00 225 Hours
Continuous		 635EDD-1000 635-752-635PT-1001 (635EDD-1000), 635EDD-1000 635PT-1001 (635EDD-1000) FH - Maintenance on Transformer, associated breakers, other equipment in isolation boundary and protection system testing.  
ATCO 11-Jun-27 10:00 12-Jun-27 17:00 31 Hours
Continuous		 959s 901T (959s Lanfine), 959s 904 (959s Lanfine), 959s 919 (959s Lanfine), 959s 701 (959s Lanfine), 959s 706 (959s Lanfine), 959s 722 (959s Lanfine), 959S 722C (959S Lanfine) Cutover MOD status, Commission inputs to RAS 204 A/B  
SUNCOR 15-Jun-27 09:00 25-Jun-27 20:00 251 Hours
Continuous		 29EDD-94 406T (29EDD-94 Voyageur), 29EDD-94 29-952-9702 (29EDD-94 Voyageur), 29EDD-94 29PS-388 (29EDD-94 Voyageur), 29EDD-94 29PS-389 (29EDD-94 Voyageur), 29EDD-94 29PS-399 (29EDD-94 Voyageur) 29EDD94;29PT-406 SYSTEM;PM 5y,10y  
ATCO 21-Jun-27 09:00 22-Jun-27 17:00 32 Hours
Continuous		 730s 703 (730s Rycroft), 7L73 (730s Rycroft - 829s Boucher Creek) BREAKER SF6 HGF COMPLETE TESTING - 703 @ 730s  
AESO, ATCO 29-Jun-27 13:00 30-Jun-27 17:00 28 Hours
Continuous		 9LA93 (973s Lanes Lake - 9L93 tap) Line to Ground Clearance Mitigation, Span 50-51. Repair deficiency on structure 57  
ATCO 19-Jul-27 10:00 22-Jul-27 15:00 77 Hours
Continuous		 813s 906 (813s Little Smoky) BREAKER SF6 HGF COMPLETE TESTING - 906 @ 813S
Breaker 906 Counter Inoperable - Correct Counter Arm at 813s Little Smoky		  
ATCO 16-Aug-27 10:00 17-Aug-27 16:00 30 Hours
Continuous		 815s 702 (815s Goodfare), 7L07 (790s Poplar Hill - 815s Goodfare) BREAKER SF6 LTB145D1/B COMPLETE TESTING - 702 @ 815S  
ATCO, ALTALINK 16-Aug-27 10:00 19-Aug-27 16:30 78.5 Hours
Continuous		 7L702 (137s Sedgewick - 757s Battle River) Interphase spacers and pole replacements  
ATCO, ALTALINK 16-Aug-27 10:00 19-Aug-27 16:30 78.5 Hours
Continuous		 702L (137s Sedgewick - 757s Battle River) Interphase spacers and pole replacements  
ALTALINK, ATCO, FMGW 17-Aug-27 08:00 18-Aug-27 17:00 33 Hours
Continuous		 964AL (1024s Granlea - 964L tap), 1024s PT-6001 (1024s Granlea), 1024s PT-6002 (1024s Granlea), 1024s 952-600001 (1024s Granlea), 1024s PS-6005 (1024s Granlea), 1024s PS-6006 (1024s Granlea), 1024s PS-6007 (1024s Granlea), 1024s PS-6008 (1024s Granlea), 1024s 489-600201 (1024s Granlea) maintenance activities (testing and inspection) of electrical equipment  
ALTALINK, BCH 23-Aug-27 07:00 03-Sep-27 17:00 274 Hours
Continuous		 1201L (520s Bennett - BCH Cranbrook), Path 1 (AIES Islanding) annual maintenance AB-BC
ALTALINK, BHE 23-Aug-27 07:00 03-Sep-27 17:00 274 Hours
Continuous		 MATL (120s Picture Butte - Montana) align with 1201L outage AB-MATL
ALTALINK, BCH 23-Aug-27 07:00 03-Sep-27 17:00 274 Hours
Continuous		 48s 887X (48s Pocaterra), 887L (48s Pocaterra - 978s BCH Britt Creek) opened because 1201L is out of service . AB-BC
ALTALINK, BCH 23-Aug-27 07:00 03-Sep-27 17:00 274 Hours
Continuous		 799s 786W (799s Coleman), 786L (799s Coleman - BCH Natal) opened because 1201L is out of service. AB-BC
ATCO, ALTALINK 23-Aug-27 10:00 27-Aug-27 16:30 78.5 Hours
Continuous		 7L702 (137s Sedgewick - 757s Battle River) Interphase spacers and pole replacements  
ATCO, ALTALINK 23-Aug-27 10:00 27-Aug-27 17:30 103.5 Hours
Continuous		 702L (137s Sedgewick - 757s Battle River) Interphase spacers and pole replacements  
ATCO 08-Nov-27 09:00 11-Nov-27 17:00 80 Hours
Continuous		 ALC02L (409s Shell Scotford - 879s Upgrader) Install new Deadend corner structure on ALC02L  
ATCO 08-Nov-27 09:00 11-Nov-27 17:00 80 Hours
Continuous		 ALC01L (408s Air Liquide Scotford - 409s Shell Scotford) Install new Deadend corner structure on ALC02L.  
ATCO 08-Feb-28 09:00 10-Feb-28 17:00 56 Hours
Continuous		 7L228 (845s Big Mountain - 7L20 tap) AESO project P2716 - Install 7L228 bypass to facilitate the installation of new line switches for the new 7LA228 T-tap line connection to the new 2103S Pakenham substation
Open 7L228, replace structures 551 and 551A, connect bypass.		  
ATCO 06-Mar-28 10:00 22-Mar-28 16:00 389 Hours
Continuous		 826s 903 (826s Marguerite Lake), 826s 907 (826s Marguerite Lake), 826s 901T (826s Marguerite Lake) Expand 240kV ring bus for new 9L42 line  
ATCO 13-Mar-28 10:00 16-Mar-28 17:00 79 Hours
Continuous		 9L939 (77s Sagitawah - 809s Louise Creek) Cut over 9L939 to temp bypass structures to allow for installation of new deadend corner towers. These are required to make the final connections to the new 2105S Jackson substation  
ATCO 14-Mar-28 09:00 16-Mar-28 17:00 56 Hours
Continuous		 7L228 (845s Big Mountain - 7L20 tap) AESO project P2716 - Disconnect bypass, connect new 7LA228D1 to 7LA228 Str #2, connect 7L228 to 7L228D2, connect 7L228 to 7L228D3. Renumber existing line switches 7L228D2 - D4, 7L228D3 - D5, 7L228D4 - D6
Commission DTT		  
ATCO 17-Mar-28 10:00 17-Apr-28 17:00 751 Hours
Continuous		 9L938 (77s Sagitawah - 809s Louise Creek) Install foundations (TBD assume concrete), assemble and erect new Q-towers 9L938/9L939-155A and 9L938/9L939-156A in existing ROW centreline. Daily outage until such a time as the new towers begin to encroach on 9L938.  
ATCO 20-Mar-28 09:00 23-Mar-28 17:00 80 Hours
Continuous		 2091s 704 (2091s Thornton) AESO project P2716 - cut over new SEL 2440 wiring at 2091S, relay programming, commission DTT and LTO  
ATCO 24-Mar-28 09:00 27-Mar-28 17:00 80 Hours
Continuous		 740s 704 (740s H.R. Milner), 7L20 (740s H.R. Milner - 810s Dome Cutbank) AESO project P2716 - cut over RAS #171 wiring at 740S, relay programming, commission LTO 7L20/7L228  
SUNCOR 04-Apr-28 08:00 07-Apr-28 19:00 83 Hours
Continuous		 29PL9-16 (29EDD-1 Millennium - 29EDD-94 Voyageur) 29EDD1;29PT418/29PL9-16 SYSTEM;PM 5y,10y
  
ATCO 18-Apr-28 10:00 25-Apr-28 17:00 175 Hours
Continuous		 9L938 (77s Sagitawah - 809s Louise Creek) Open 9L938 conductors, complete assembly and connect to the new Q-Towers 9L938/9L939-155A and 9L938/9L939-156A, string to 2105S Jackson deadend and terminate.
Relabel 9L938 segment from 809S Louise Creek to 2105S Jackson to 9L140.		  
ATCO 01-May-28 10:00 04-May-28 17:00 79 Hours
Continuous		 9L939 (77s Sagitawah - 809s Louise Creek) Disconnect 9L939 conductors from temp structure 9L939 -155A - 155E reconnect to existing structures 9L938/9L939-156 and 9L938/9L939-155, connect to the new Q-Towers 9L938/9L939-155A and 9L938/9L939-156A, string to 2105S Jackson deadend and terminate.
Relabel 9L939 segment from 809S Louise Creek to 2		  
SUNCOR 03-May-28 14:00 12-May-28 18:00 220 Hours
Continuous		 29EDD-65 29PT-0236 (29EDD-65), 29EDD-65 29-952-4823 (29EDD-65), 29EDD-65 29-952-4822 (29EDD-65), 29EDD-71 752-4634 (29EDD-71), 29EDD-71 752-4633 (29EDD-71), 29PL7-3 (29EDD-65 - 29EDD-71) Firebag: 29EDD65;29PT-236 & 29PL7-3 SYSTEM, 29EDD65;29PT-250&29PL7-3 SYSTEM, 29PT-246 SYSTEM;29EDD71  
ATCO 08-May-28 09:00 10-Jul-28 17:00 1,520 Hours
Continuous		 959s 240kV Bus 900BS2 (959s Lanfine) GOI on 9L141 until line terminated into 1162S Fair Acres and ready to energize  
ATCO 08-May-28 09:00 10-Jul-28 17:00 1,520 Hours
Continuous		 959s 240kV Bus 900BS2 (959s Lanfine) GOI on 902/903 until line terminated and 1162S Fair Acres ready to energize  
ATCO 09-May-28 10:00 13-May-28 17:00 103 Hours
Continuous		 9L02 (809s Louise Creek - 813s Little Smoky) Install concrete foundations for new structures 9L02/320A, 320H in preparation to cut into 9L02 and convert to a t-tap.  
ATCO 15-May-28 09:00 17-May-28 17:00 56 Hours
Continuous		 959s 240kV Bus 900BS1 (959s Lanfine) Connect new bus from new 902B to existing switch 901A to add new line 9L141,
Cutover and commission 900PT1 ccts to new 9L141 relays		  
ATCO 18-May-28 09:00 20-May-28 17:00 56 Hours
Continuous		 959s 240kV Bus 900BS2 (959s Lanfine) Connect new bus from new Bkr 903 to existing switch 903B to add new line 9L141,
Cutover and commission 900PT2 ccts to new 9L141 relays		  
ATCO 29-May-28 09:00 08-Jun-28 17:00 248 Hours
Continuous		 9L24 (946s Oakland - 959s Lanfine) Cutover and commission 905/906 CT's, 9L24PT ccts to new RAS 241 SEL 451A/B relays @ 959S Lanfine and update relay settings for RAS 241 and SCADA inputs @946S Oakland.  
ATCO 19-Jun-28 10:00 30-Jun-28 16:00 270 Hours
Continuous		 9L20 (755s Cordel - 766s Nevis)
Install concrete foundations at 9L20 Structure 69 for new T-Tap connection		  
ATCO 26-Jun-28 10:00 10-Jul-28 17:00 343 Hours
Continuous		 9L02 (809s Louise Creek - 813s Little Smoky) Cut into 9L02 and connect new t-tap structures for 9LA02.
9L02-21A and 21B relay upgrades at 809S Louise Creek and 813S Little Smoky. Implement RAS
Energize new line 9LA02 and 884S Magpie substation		  
ATCO 31-Jul-28 10:00 15-Aug-28 16:00 366 Hours
Continuous		 766s 901 (766s Nevis), 9L20 (755s Cordel - 766s Nevis), 755s 906 (755s Cordel), 755s 901 (755s Cordel)
Cutover new 9L20 line section, terminate 9LA20 at customer substation. Install new line protection relays		  
ATCO 01-Oct-28 08:00 21-Oct-28 16:00 488 Hours
Continuous		 972s 904 (972s Tinchebray) CETO project
Install 904 and 904CT

Commission 904 and 904CT

Expand GOI to 900BS1
Isolation Points: 904A, 901A and 900SST1X
Connect 907B to 900BS1
Shrink GOI to 907B		  
ATCO 22-Oct-28 08:00 20-Nov-28 16:00 705 Hours
Continuous		 972s 906 (972s Tinchebray) CETO project
Install 906 and 906CT

Commission 906 and 906CT

Expand GOI to 900BS2 OCT 22 2028 - NOV 20 2028
Isolation Points: 906A, 902B and 9L16D1@ CORDEL
Connect 909A to 900BS2
Commission Logic and breaker fail
Shrink GOI to 9L86D1
String 9L86 into 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: 2026-09-29   15:47:33


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.

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