Alberta Electric System Operator

Long Term Critical Transmission Outages > 10 days (Revised 2012-02-02)

The following table contains the critical transmission maintenance 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 critical for this table if it affects:

- a 500 kV Line, Breaker, Bus or Transformation,

- a 240 kV Line, Breaker, Bus or Transformation,

- the interconnection of the AIES to an external transmission system, specifically the BC intertie or the

Saskatchewan intertie

- a significant component of the AIES, is an interconnecting element between transmission facility owners,

or connects a generating unit to the AIES

- requires curtailing generation to facilitate the outage.

Note: Where a transmission outage requires generation curtailments, the adjustments to generation will typically

happen in the hour before the scheduled transmission outage and in the hour after the element is returned to service.

Owner From To Duration Element Scheduled Activity Affected Intertie*

ENMAX 27-Oct-11 8:00 15-Feb-12 16:00 Continuous ENMAX 31.1 cap bank (FORCED) forced outage AB-BC

ATCO 16-Nov-11 1:00 29-Feb-12 17:00 Continuous 828s Sulphur Point 507C1 and 507C2 damage (one wafer blow up)

(forced outage)

ENMAX 13-Jan-12 17:01 15-Mar-12 16:00 Continuous 162B240-RB135 (162s Beddington) moved to replace failed breaker RB135

ATCO 19-Jan-12 17:00 04-Apr-12 17:00 Continuous 856s900BUS1 (no outage) install new 240 kV breakers and associated

equipment

AltaLink 03-Feb-12 8:00 27-Feb-12 16:00 Continuous 1045L (310p - E805s) Advice for Epcor EPCOR re-stringing portion of 1045L

EPCOR 03-Feb-12 8:00 28-Feb-12 16:00 Continuous 1045L (805s Jasper - 310p Sundance) Jasper re-string project

AltaLink 07-Feb-12 17:30 21-Feb-12 17:00 Continuous 928L (17s Benalto-42s Sarcee) line move AB-BC

ENMAX 10-Feb-12 19:30 12-Feb-12 19:30 C 917L (74s Janet - 5s East Calgary) install new structure

AltaLink 13-Feb-12 8:00 16-Feb-12 17:00 Continuous 17s8 GOI. Replace 240KV CT

AltaLink 13-Feb-12 8:00 17-Feb-12 17:00 Daily 913L(69s-A732s) Advice for ATCO Pole replacement and mitigation

maintenance.

ATCO 13-Feb-12 8:00 14-Feb-12 17:00 Continuous 888S DOVER 888S900BS1 CUTTING IN JUMPER "J1" @ 888S DOVER

900BS1

EPCOR 13-Feb-12 8:00 15-Feb-12 16:00 Continuous 1056 Line 814S Bellamy to 89S Ellerslie SF6 Gas Maintenance (High Moisture)

ATCO 13-Feb-12 8:30 17-Feb-12 17:30 Continuous 9L913 9L913 replace poles

ATCO 14-Feb-12 17:00 01-Mar-12 17:00 Continuous 888S DOVER 888SPORTION900BS1 install new equipment

AltaLink 15-Feb-12 9:00 15-Feb-12 17:00 71s1052 (C2) GOI maintain SF6 240 kV ABB - HPL capbank

AltaLink 16-Feb-12 9:00 16-Feb-12 17:00 54s45 (C1) GOI C/S & Cap Bank Maintenance

AltaLink 20-Feb-12 8:00 24-Feb-12 17:00 Daily 913L(69s-A732s) Advice for ATCO Pole replacement and mitigation

maintenance.

ATCO 20-Feb-12 8:30 24-Feb-12 17:30 Continuous 9L913 9L913 replace poles

AltaLink 21-Feb-12 8:00 24-Feb-12 17:00 Continuous 17s12 GOI. Replace 240KV CT

AltaLink 21-Feb-12 8:00 24-Feb-12 17:00 Continuous 368s35 GOI Replace CTs.

AltaLink 21-Feb-12 11:00 22-Feb-12 17:00 Continuous 370s56 GOI 240kV Breaker Maintenance

AltaLink 23-Feb-12 9:00 23-Feb-12 17:00 59s452 GOI 240kV Breaker Maintenance

AltaLink 27-Feb-12 8:00 02-Mar-12 17:00 Continuous 17s5 GOI. Replace 240KV CT

AltaLink 27-Feb-12 8:00 02-Mar-12 17:00 Continuous 901L (74s-64s-63s) GOI Construction AB-BC

AltaLink 27-Feb-12 8:00 02-Mar-12 17:00 1005L (356s-370s) GOI Construction

AltaLink 27-Feb-12 8:00 29-Feb-12 16:00 Continuous 72s990 (990L) Advice for ATCO Raise 9L990 for 7L104 construction - ATCO

ATCO 27-Feb-12 8:30 02-Mar-12 17:30 Continuous 9L913 9L913 replace poles

AltaLink 27-Feb-12 9:00 27-Feb-12 14:00 256s C1 GOI Remove Bird Nest

AltaLink 29-Feb-12 9:00 29-Feb-12 17:00 72s652 GOI 240 kV Breaker Maintenance

ATCO 02-Mar-12 7:00 02-Mar-12 19:00 9L57 9L57 INSTALLING TEMPORARY BYPASS

ATCO 02-Mar-12 19:00 30-Mar-12 8:00 Continuous 9L57 PART9L57 BUILDING IN/OUT TO NEW 939S LIVOCK

ATCO 05-Mar-12 7:30 09-Mar-12 16:00 Continuous 9L990 9L990 raising line for future substation

AltaLink 05-Mar-12 8:00 08-Mar-12 17:00 Continuous 1036L (356s-370s) GOI Construction

AltaLink 05-Mar-12 8:00 08-Mar-12 17:00 Continuous 17s7 GOI. Replace 240KV CT

AltaLink 05-Mar-12 8:00 09-Mar-12 17:00 Daily 913L(69s-A732s) Advice for ATCO pole replacement and mitigation maintenance

ATCO 05-Mar-12 8:00 12-Mar-12 17:00 Continuous 9L961 9L961 required for new construction at 825s

Whitefish

ATCO 05-Mar-12 8:30 09-Mar-12 17:30 Continuous 9L913 9L913 replace poles

ATCO 11-Mar-12 8:00 13-Mar-12 16:00 Continuous 977S SALT CREEK 9L85 connect to 977s Salt Creek

AltaLink 12-Mar-12 8:00 15-Mar-12 17:00 Continuous 908L(38s-E52s-89s)GOI. Construction. Thermal upgrade

ATCO 12-Mar-12 8:00 19-Mar-12 17:00 Continuous 825S WHITEFISH 825S904 REQUIRED FOR NEW CONSTRUCTION @

825S WHITEFISH

AltaLink 13-Mar-12 8:00 13-Mar-12 17:00 912L (63s-A766s) GOI YTG relay replacement

ATCO 14-Mar-12 6:30 18-Mar-12 18:00 Continuous 9L55 9L55 install new towers for future tap-off

AltaLink 15-Mar-12 8:00 15-Mar-12 17:00 63s (925L) GOI YTG Relay Replacement AB-BC

EPCOR 15-Mar-12 8:00 15-Apr-12 16:00 Continuous 1056 Line 814S Bellamy to 89S Cable maintenance

Ellerslie

AltaLink 16-Mar-12 8:00 19-Mar-12 17:00 Continuous 908L(89s-E816s) GOI Construction. Thermal upgrade

AltaLink 19-Mar-12 8:00 20-Mar-12 17:00 Continuous 903L(17s300) GOI Replace B and C phases of 17s300 Pts(899 AB-BC

and 901)

ATCO 19-Mar-12 8:00 04-Apr-12 17:00 Continuous 9L22 9L22 REQUIRED FOR NEW CONSTRUCTION @

825S WHITEFISH

ATCO 19-Mar-12 8:00 18-Jun-12 16:00 Continuous 801s Anderson 801s907 rebuild new bay for 9L33

AltaLink 20-Mar-12 8:00 23-Mar-12 17:00 Continuous 909L (89s-E665s) GOI Construction. Thermal upgrade

AltaLink 21-Mar-12 8:00 29-Mar-12 17:00 Continuous 913L (69s - 310p) GOI cut in new 338s station

AltaLink 24-Mar-12 8:00 28-Mar-12 17:00 Continuous 909L (320p-E665s) GOI Construction. Thermal upgrade

ATCO 30-Mar-12 8:00 30-Mar-12 16:00 9L57 9L57 closing jumper J1

EPCOR 15-Apr-12 8:00 15-May-12 16:00 Continuous 1056 Line 814S Bellamy to 89S Ellerslie Cable maintenance

AltaLink 16-Apr-12 11:00 19-Apr-12 17:00 Continuous 19sT10 GOI 19s T10 tapchanger overhaul

AltaLink 21-Apr-12 8:00 24-Apr-12 17:00 Continuous 42s 240 kV North(T1) & South(T2) and create an open point AB-BC

906L

AltaLink 01-May-12 8:00 14-May-12 17:00 Continuous 102s SVC GOI & 240kv west bus replace SVC TX

AltaLink 02-May-12 8:00 03-May-12 17:00 Continuous 163s1352 GOI 240kV Breaker Maintenance

AltaLink 14-May-12 8:00 22-May-12 17:00 Continuous 100L (498s-895s) GOI Line move to accommodate road widening

near 895s

AltaLink 14-May-12 8:00 14-May-12 17:00 917L (74s-5s) GOI Construction carry over

ATCO 19-May-12 9:00 20-May-12 16:00 Continuous 9L59 9L59 create a temp by-pass for the Tinchebray

ATCO 20-May-12 8:00 22-May-12 8:00 Continuous 9L950 9L950 Install Tap-off structor piles

ATCO 01-Jun-12 9:00 08-Jun-12 16:00 Continuous 9L950 9L950 REROUTE 9L950 TO ALLOW FOR

OAKLAND CROSS-OVER

ATCO 04-Jun-12 8:00 05-Jun-12 16:00 Continuous 801S ANDERSON 801S901T&701T INSTALL RIDER POLES NEAR 901T AND

701T, THIS WILL OPEN-END 7L85

ATCO 19-Jun-12 8:00 03-Aug-12 16:00 Continuous 801S ANDERSON REBUILD OLD 9L933 BAY FOR 9L97

801SBKRS905&906

ATCO 25-Jun-12 9:00 26-Jun-12 16:00 Continuous 9L59 9L59 CUT-IN NEW TINCHEBRAY

AltaLink 16-Jul-12 8:00 19-Jul-12 17:00 Continuous 172L (83s - 172L944A) Work between str 328 & 951. Structure and

cross arm

ATCO 06-Aug-12 8:00 02-Nov-12 16:00 Continuous 801S ANDERSON 801SBKR903 REBUILD NEW BAY FOR 9L933

ATCO 13-Nov-12 8:00 20-Nov-12 16:00 Continuous 801s Anderson 801s905 & 801s906 connect new 9L97 to bay

ATCO 21-Nov-12 8:00 22-Nov-12 16:00 Continuous 801s Anderson 801S901T&701T remove rider poles

ATCO 01-Apr-13 8:00 30-Jun-13 17:00 Continuous 840s McNeill HVDC control system upgrade AB-SK

[1] AB-BC & AB-SK: refer to AESO web posting: http://itc.aeso.ca/itc/public/atcQueryInit.do

Also,

[2] AB-BC: refer to OPP-304 at: http://www.aeso.ca/rulesprocedures/9073.html

[3] AB-SK: typical impact is ATC = 0

Prepared on: February-02-2012 16:47

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.